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    • 专利摘要:
    In accordance with an irradiation position of a pulse light, a selecting unit outputs a first transfer signal to first transfer electrodes (TX1) and outputs a second transfer signal to second transfer electrodes (TX2) so that signal charges into first and second signal charge collecting sections (9a and 9b) of a pixel from a plurality of pixels corresponding to the irradiation position, and outputs a third transfer signal to third transfer electrodes (TX3), so that unnecessary charges in a non-required charge discharge portion (11) of one pixel among the plurality of pixels except of the pixel can flow according to the irradiation position. An arithmetic unit reads out signals corresponding to respective magnitudes of signal charges included in the first and second signal charge collecting sections (9a and 9b) of the pixel selected by the selecting unit, and calculates a distance to an object based on a ratio between a magnitude of signal charges, collected in the first signal charge collecting sections (9a) and a quantity of signal charges collected in the second signal charge collecting sections (9b).
    公开号:CH711394B1
    申请号:CH01575/16
    申请日:2015-05-28
    公开日:2018-03-15
    发明作者:Mase C/O Hamamatsu Photonics K K Mitsuhito；Hiramitsu C/O Hamamatsu Photonics K K Jun；Shimada C/O Hamamatsu Photonics K K Akihiro
    申请人:Hamamatsu Photonics Kk；
    IPC主号:
    专利说明:

    Description TECHNICAL FIELD The present invention relates to a distance measuring apparatus.
    Background Art Known range finding apparatuses include a scanning unit for scanning an irradiation position on an object of pulse light emitted from a light source, a light receiving unit having a plurality of pixels arranged in a one-dimensional direction, and in the reflected light of the pulse light reflected from the object is incident, and an arithmetic unit for reading out signals from the plurality of pixels and calculating a distance to the object (see, for example, Patent Literature 1). The distance measuring apparatus described in Patent Literature 1 performs time-of-flight (TOF) -type ranging.
    List of Patent Literature Patent Literature 1: International Publication No. 2013/121267 Summary of the Invention
    Technical Problem In the distance measuring apparatus described in Patent Literature 1, a reset operation is performed every time charges accumulate and unnecessary charges are discharged from pixels. This can prevent charges (unnecessary charges) generated in accordance with the incidence of ambient light from being accumulated as signal charges, and prevents components of an ambient light from being reproduced from the pixels in the signal readout.
    In order to increase a range finding accuracy, moreover, sufficient signal quantity must be secured when the signals are read out from the pixels. In the distance measuring apparatus described in Patent Literature 1, as explained above, a reset operation is carried out each time charges are accumulated. It is therefore necessary to set a charge accumulation period in each pixel to a relatively long period to ensure a sufficient signal quantity. A sampling period performed by the sampling unit must also be set to a long period in accordance with the charge accumulation period. Therefore, in the distance measuring apparatus described in Patent Literature 1, when the object is moving, it may become difficult to accurately measure the distance.
    The object of the present invention is therefore to provide a distance measuring device which can measure a distance suitable and accurate. Solution to the Problem A distance measuring apparatus according to one aspect of the present invention includes a scanning unit for scanning an irradiation position on an object of pulse light emitted from a light source, a light receiving unit having a plurality of pixels arranged in a one-dimensional direction, and in which reflected light of the pulse light reflected from the object is incident, a selecting unit for selecting, among the plurality of pixels, a pixel from which a signal is to be read, in accordance with the irradiation position of the pulse light sampled by the scanning unit, and an arithmetic unit for reading out a signal from the pixel selected by the selecting unit and calculating a distance to the object. Each of the plurality of pixels includes a charge generating section for generating charges in accordance with an incident light, first and second signal charge collecting sections located away from the charge generating section, and for collecting the charges generated in the charge generating section as signal charges, a non-requirement a charge-discharge section disposed away from the charge-generating section and discharging charges generated in the charge-generating section as unnecessary charges; a first transfer electrode disposed between the first signal charge collecting section and the charge-generating section; and for allowing the charges generated in the charge generating section to flow into the first signal charge collecting section as the signal charges, in accordance with a first transfer signal, a second transfer electrode connected between the first and second transfer charges second signal charge collecting section and the charge generating section, and for allowing charges generated in the charge generating section to flow into the second signal charge collecting section as signal charges in accordance with a second transfer signal in phase from the first transfer signal and a third transfer electrode disposed between the non-required-discharging discharge section and the charge-generating section, and for allowing the charges generated in the charge-generating section to flow into the non-discharging-discharging section as unnecessary charges, in accordance with a third transfer signal that differs in one phase from the first and second transfer signals. In accordance with an irradiation position of the pulse light sampled by the scanning unit, the selecting unit outputs the first transfer signal to the first transfer electrode and outputs the second transfer signal to the second transfer electrode to allow the signal charges to be reflected in the first and second signal charge collection sections of the pixel corresponding to the irradiation position, among the plurality of pixels, and outputs the third transfer signal to the third transfer electrode to allow the unnecessary charges to flow into the non-required charge discharge portion of the pixel except for the pixel corresponding to the irradiation position , among the multitude of pixels. The arithmetic unit reads out signals corresponding to respective magnitudes of the signal charges accumulated in the first and second signal charge collecting sections of the pixel selected by the selecting unit, and calculates a distance to the object based on a relation between the magnitude of the first in the first Signal charge collection section collected charges and the size of the signal charges collected in the second signal collection section.
    In the one aspect of the present invention, the selecting unit outputs the first transfer signal to the first transfer electrode of the pixel in accordance with the irradiation position of the pulse light, so that the signal charges can flow into the first signal charge collection section of the pixel. The selecting unit outputs the second transfer signal different in phase from the first transfer signal to the second transfer electrode of the above-described pixel according to the irradiation position of the pulse light, so that the signal charges can flow in the second signal charge collection section of the pixel. In other words, the charges generated in the charge generating portion of the pixel selected by the selecting unit are distributed to the first signal charge collecting section and the second signal charge collecting section as the signal charges, and the signal charges are accumulated in the corresponding signal charge collecting sections. The selecting unit outputs the third transfer signal to the third transfer electrode of the pixel except for the above-described pixel corresponding to the irradiation position of the pulse light, so that the unnecessary charges can flow into the non-required-charge discharging portion of the pixel. In the pixel other than the pixel in which signal charges are accumulated, in other words, the charges generated in the charge generating portion of the pixel are discharged from the non-required-charge discharge portion as unnecessary charges. The arithmetic unit reads out the signals corresponding to the respective magnitudes of the signal charges collected in the first and second signal charge collecting sections of the pixel selected by the selecting unit, and calculates the distance to the object based on the ratio between the magnitude of the signal charges collected in the first one Signal charge collecting section, and the size of the signal charges collected in the second signal charge collecting section. In view of these aspects, in the pixel other than the pixel in which signal charges are accumulated, charges generated in the charge generating portion of the pixel are discharged as unnecessary charges. Therefore, a charge amount based on unnecessary charges becomes difficult to reproduce in the calculation of the distance to the object. A distance measurement can therefore be carried out suitably and accurately.
    In one embodiment, the selection unit in the selected pixel may output the first transfer signal to the first transfer electrode and output the second transfer signal to the second transfer electrode so that charges may flow into the first and second signal charge collection sections at a timing is different from a time when signal charges are caused to flow into the first and second signal charge collection sections, and at a time when the pulse light is not emitted from the light source, and the arithmetic unit may be spaced from the object calculating based on a ratio between a magnitude of signal charges collected in the first signal charge collection section obtained by subtracting a magnitude of signal charges collected in the first signal charge collection section at a time when the pulse light is not from the light source is emitted and a magnitude of signal charges accumulated in the second signal charge collection section obtained by subtracting a magnitude of charges collected in the second signal charge collection section at a time when the pulse light is not emitted from the light source.
    According to the above-described embodiment, the selecting unit outputs the first transfer signal in the selected pixel, so that the charges can flow into the first signal charge collecting section at a timing different from the time when it is caused the signal charges flow into the first and second signal charge collection sections, and at a time when the pulse light is not emitted from the light source. In the selected pixel described above, the selecting unit outputs the second transfer signal so that charges can flow into the second signal charge collecting section at the time different from the timing at which the signal charges are made into the first and second Signal charge collection sections flow, and at the time when the pulse light is not emitted from the light source. In the charge generation portion of the pixel selected by the selection unit, the charges not generated by the emission of the pulse light corresponding to the pixel are in other words distributed to the first signal charge collection section and the second signal charge collection section, and collected in the respective sections. The arithmetic unit calculates the distance to the object based on the ratio between the magnitude of the signal charges collected in the first signal charge collecting section obtained by subtracting the magnitude of the charges collected in the first signal charge collecting section at the time to which the pulse light is not emitted from the light source and the magnitude of the signal charges collected in the second signal charge collection section obtained by subtracting the magnitude of the charges collected in the second signal charge collection section at the time the pulse light is not emitted from the light source. By subtracting the charges which are not generated by the emission of the pulse light corresponding to the selected pixel, the amount of charge based on an ambient light such as the background light can be difficult to be reflected in the calculation of the distance to the object. A distance measurement can therefore be carried out better and more accurately.
    Advantageous Effects of Invention According to the above-described one aspect of the present invention, there can be provided a distance measuring apparatus which can measure a distance properly and accurately.
    Short description of the drawings [0012]
    FIG. 1 is an explanatory diagram showing a configuration of a distance measuring apparatus according to an embodiment of the present invention. FIG.
    FIG. 2 is a diagram illustrating a cross-sectional configuration of a ranging image sensor. FIG.
    Fig. 3 is a configuration diagram of the ranging image sensor.
    FIG. 4 is a diagram illustrating a configuration of a cross section taken along one shown in FIG. 3
    Line IV-IV.
    FIG. 5 is a diagram illustrating a configuration of a cross section along a line V-V shown in FIG. 3.
    6 is a diagram illustrating a potential profile in the vicinity of a second main surface of a semiconductor substrate.
    FIG. 7 is a diagram illustrating a potential profile in the vicinity of the second main surface of the semiconductor substrate. FIG.
    Fig. 8 is a timing chart of various signals.
    Fig. 9 is a diagram showing a relationship between a timing chart of various signals and pixels to be selected.
    Fig. 10 is a diagram illustrating a relationship between a movement of a reflection element and a pixel.
    11 is a diagram illustrating a relationship between a timing chart of various signals and a pixel to be selected according to a modified example of the present embodiment.
    FIG. 12 is a diagram illustrating a relationship between a movement of a reflection element and a pixel according to the modified example of the present embodiment. FIG.
    DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of the present invention will be explained in detail with reference to the drawings. In the description, the same elements or elements having the same functionality are denoted by the same reference numerals without a redundant description.
    Fig. 1 is an explanatory diagram showing a configuration of a distance measuring apparatus according to the present embodiment.
    A distance measuring device 1 is a device for measuring a distance d to an object OJ. The distance measuring device 1 includes a ranging image sensor RS having a plurality of pixels, a light source LS, a reflection element MR, a display DSP and a control unit. The control unit includes a driver unit DRV, a control unit CONT and an arithmetic unit ART. The light source LS emits pulse light Lp in the direction of the reflection element MR. The light source LS includes, for example, a laser light irradiation device or an LED. The ranging image sensor RS is a TOF-type ranging image sensor. The distance-measuring image sensor RS is arranged on a printed circuit board or a board WB.
    The control unit (the drive unit DRV, the control unit CONT, and the arithmetic unit ART) include hardware having an arithmetic circuit such as a central processing unit (CPU), a memory such as a random access memory (RAM), and a memory Read-only memory (ROM), a circuit and a readout circuit with an A / D converter. The entirety or a part of the control unit may be formed by an integrated circuit, such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).
    The drive unit DRV supplies a drive signal SD to the light source LS in accordance with a control of the control unit CONT. Specifically, the drive unit DRV drives the light source LS to emit the pulse light Lp toward the reflection element MR per frame period. The drive unit DRV supplies a drive signal to an actuator of the reflection element MR in accordance with the control of the control unit CONT. That is, the drive unit DRV drives the actuator to change a light path of the pulse light Lp emitted from the light source LS toward the reflection element MR. The reflection element MR reflects the pulse light Lp emitted from the light source LS. The reflected pulse light Lp is irradiated to the object OJ. The actuator deflects an angle of the reflection element MR in accordance with the drive signal from the drive unit DRV. As a result, an irradiation position Pi on the object OJ of the pulse light Lp emitted from the light source LS is scanned. In the present embodiment, the drive unit DRV and the reflection element MR operate as a scanning unit for scanning the irradiation position on the object OJ of the pulse light Lp emitted from the light source LS. The reflection element MR is, for example, a microelectromechanical system (MEMS) mirror.
    The control unit CONT controls the drive unit DRV and outputs a first to third transfer signal STX1, STX2 and STX3 to the ranging image sensor RS. The control unit CONT displays an arithmetic result of the arithmetic unit ART on the display DSP. The control unit CONT includes a selection unit SEL. The selecting unit SEL selects a pixel from which a signal is to be read out of the plurality of pixels included in the ranging image sensor RS according to the irradiation position on the object OJ of the pulsed light Lp. The arithmetic unit ART reads charge quantities Qi and Q2 (total charge quantities Οτι and Or2) of signal charges from the pixel selected by the selection unit SEL. On the basis of the read charge quantities Οί and Q2 (total charge quantities Gn and Gt2), the arithmetic unit ART calculates the distance d for each pixel, and outputs the obtained arithmetic result to the control unit CONT. The calculation method of the distance d will be explained later with reference to FIG. The display DSP indicates the arithmetic result of the arithmetic unit ART output from the control unit CONT.
    In the distance measuring apparatus 1, by applying the drive signal SD to the light source LS, the pulse light Lp is emitted from the light source LS per frame period. The pulse light Lp emitted from the light source LS is scanned by the reflection element MR. The pulse light Lp incident on the object OJ is reflected by the object OJ. The pulse light Lp incident on the object OJ is therefore emitted from the object OJ as reflected light Lr. The reflected light Lr emitted from the object OJ is incident on a charge generation section of the ranging image sensor RS.
    The charge quantities QTi and QT2 (total charge quantities Οπ and QT2), which are collected in synchronism with the first and second transfer signals STX1 and STX2, are output for each pixel from the ranging image sensor RS. The output amounts of charge Qu and Qt2 (total charge quantities QTi and Qt2) are input to the arithmetic unit ART in synchronization with the drive signal SD. Based on the input charge quantities QTi and QT2 (total charge quantities QT1 and QTi), the arithmetic unit ART calculates the distance d for each pixel. The control unit CONT receives the arithmetic result of the arithmetic unit ART from the arithmetic unit ART. The control unit CONT transfers the inputted arithmetic result of the arithmetic unit ART to the display DSP. The display DSP displays the arithmetic result of the arithmetic unit ART.
    FIG. 2 is a diagram illustrating a cross-sectional configuration of the ranging image sensor. FIG.
    The ranging image sensor RS is a front-mounted ranging image sensor and includes a semiconductor substrate 2. The semiconductor substrate 2 has first and second main surfaces 2a and 2b opposed to each other. The second main surface 2b is a light incident surface. The distance-measuring image sensor RS is fixed to the circuit board WB via an adhesion section FL, in a state in which the side of the first main surface 2a of the semiconductor substrate 2 faces the circuit board WB. The adhesion portion FL contains an insulating adhesive or filler. The reflected light Lr is incident on the distance-measuring image sensor RS from the second main surface 2b side of the semiconductor substrate 2.
    In the following, the distance-measuring image sensor RS will be explained in detail with reference to FIGS. 3 to 5. Fig. 3 is a configuration diagram of the ranging image sensor. FIG. 4 is a diagram showing a configuration of a cross section along a line IV-IV shown in FIG. 3. FIG. FIG. 5 is a diagram illustrating a configuration of a cross section along a line V-V shown in FIG. 3.
    As shown in FIG. 3, the ranging image sensor RS is a line sensor having an ar-ray structure in which a plurality of ranging sensors (five rangefinding sensors in the present embodiment) P in a one-dimensional direction A are arranged. One or two or more sensors of the plurality of range finding sensors P form a pixel (channel: ch) of the ranging image sensor RS. In the present embodiment, each of the ranging sensors P forms one pixel of the ranging image sensor RS. In the present embodiment, the ranging image sensor RS operates as a light receiving unit having a plurality of pixels arranged in a one-dimensional direction and in which the reflected light Lr of the pulse light reflected from the object OJ is incident.
    The ranging image sensor RS includes a light intercepting layer LI in front of the second main surface 2b, which is a light incident surface. A plurality of apertures Lia are formed in the light intercepting layer LI in a one-dimensional direction A. The plurality of apertures Lia are formed in portions corresponding to the plurality of range finding sensors P. The apertures Lia have a rectangular shape. In the present embodiment, the apertures Lia have an elongated shape. Light passes through the apertures Lia of the light intercepting layer LI and is incident on the semiconductor substrate 2. A light receiving section on the semiconductor substrate 2 is therefore defined by the aperture Lia. The light intercepting layer LI is made of a metal such as aluminum. In Fig. 3, moreover, the illustration of the light intercepting layer LI is omitted.
    The semiconductor substrate 2 includes a p-type first semiconductor portion 4 positioned on the side of the first semiconductor surface 2a, and a p "-type second semiconductor portion 5 having a lower impurity concentration than that of the first semiconductor portion 4 and is on the side the second major surface 2b positioned. The semiconductor substrate 2 may be obtained, for example, by growth on a p-type semiconductor substrate, a p_-type epitaxial layer having a lower impurity concentration than that of the p-type semiconductor substrate. An insulating layer 7 is formed on the second main surface 2b of the semiconductor substrate 2 (the second semiconductor portion 5). The plurality of range finding sensors P are arranged on the semiconductor substrate in the one-dimensional direction A. That is, the plurality of range finding sensors P are positioned on the semiconductor substrate 2 so as to be aligned along the one-dimensional direction A.
    As shown in Figs. 3 to 5, each of the range finding sensors P includes a photogate electrode PG, a pair of first signal charge collection sections 9a, a pair of second signal charge collection sections 9b, a pair of non-required ones Charge discharge sections 11 and a pair of first to third transfer electrodes TX1, TX2 and TX3. In Fig. 3, electric line elements 13 (refer to Figs. 4 and 5) disposed on the first and second signal charge collecting sections 9a and 9b and the non-required charge discharge sections 11 are omitted.
    The photogate electrode PG is arranged corresponding to the aperture Lia. A portion corresponding to the phototooth electrode PG (a portion located below the photogate electrode PG in FIGS. 4 and 5) in the semiconductor substrate 2 (the second semiconductor portion 5) functions as a charge generating portion (a photosensitive member). photosensitive portion) which generates charges in accordance with an incidence of the reflected light Lr of the pulse light Lp reflected from the object OJ. The photogate electrode PG also corresponds to the shape of the aperture Lia and has a rectangular shape in a plan view. In the present embodiment, the photogate electrode PG has an elongated shape, comparable to the aperture Lia. That is, the photogate electrode PG has a planar shape, with the first and second long side edges L1 and L2 being parallel to the one-dimensional direction A and facing each other, and the first and second short side edges S1 and S2 being orthogonal to the first one-dimensional direction A and are located opposite each other.
    The pair of first signal charge collecting sections 9a is disposed on the side of a first long side edge L1 of the photogate electrode PG along the first long side edge L1. The pair of first signal charge collection sections 9a is disposed away from the photogate electrode PG. The pair of second signal charge collecting sections 9b is disposed on the side of a second long side edge L2 of the photogate electrode PG along the second long side edge L2. The pair of second signal charge collecting sections 9b is disposed away from the photogate electrode PG. In each of the range finding sensors P, the first and second signal charge collecting sections 9a and 9b are disposed away from the charge generating section (the section located below the photogate electrode PG). The first signal charge collecting sections 9a and the second signal charge collecting sections 9b face each other with the photogate electrode PG therebetween in a direction in which the first and second long side edges L1 and L2 face each other (a direction orthogonal to the one-dimensional direction A).
    The first and second signal charge collecting sections 9a and 9b are n-type semiconductor sections formed on the second semiconductor section 5 and having a high impurity concentration. The first and second signal charge collecting sections 9a and 9b accumulate the charges generated in the charge generating section as signal charges, and accumulate the collected charges. The first and second signal charge collecting sections 9a and 9b have a rectangular shape in a plan view. The first and second signal charge collecting sections 9a and 9b have a square shape in a plan view in the present embodiment, and both have the same shape. The first and second signal charge collecting sections 9a and 9b are floating diffusion sections.
    The first transfer electrodes TX1 are disposed on the insulating layer 7 and between the photogate electrode PG and the first signal charge collecting sections 9a. The first transfer electrodes TX1 are disposed away from the first signal charge collection sections 9a and the photogate electrode PG. In accordance with the first transfer signal STX1, the first transfer electrodes TX1 allow the charges generated in the charge generation section to flow as signal charges to the first signal charge collection sections 9a.
    The second transfer electrodes TX2 are provided on the insulating layer 7 and between the photogate electrode PG and second signal charge collecting sections 9b. The second transfer electrodes TX2 are disposed away from the second signal charge collection sections 9b and the photogate electrode PG. According to the second transfer signal STX2, the second transfer electrodes TX2 allow the charges generated in the charge generation section to flow as signal charges to the second signal charge collection sections 9b.
    The first and second transfer electrodes TX1 and TX2 have a rectangular shape in a plan view. In the present embodiment, the first and second transfer electrodes TX1 and TX2 have an oblong shape having a long-side edge direction set in a direction in which the first and second short edge sides S1 and S2 of the photogate electrode PG face each other. The lengths in the long side edge direction of the first and second transfer electrodes TX1 and TX2 are set to the same length.
    On the side of the first long side edge lider photogate electrode PG, the non-required charge discharge section 11 is disposed away from the first signal charge collecting section 9a so as to be included in the direction by the pair of first signal charge collecting sections 9a in which the first and second short side edges S1 and S2 are opposite to each other (the one-dimensional direction A). On the side of the second long side edge L2 of the photogate electrode PG, the non-required charge discharge section 11 is disposed away from the second signal charge collecting sections 9b so as to be enclosed in the direction by the pair of second signal charge collecting sections 9b. in which the first and second short sides S1 and S2 are opposite to each other (the one-dimensional direction A). Each of the non-required charge discharge portions 11 is arranged at a distance from the photogate electrode PG. Each of the non-required charge discharge sections 11 is disposed away from the charge generation section (the portion located below the photogate electrode PG). The non-required charge discharge portions 11 are opposed to each other so that the photogate electrode PG is included in the direction in which the first and second long sides LI and L2 face each other.
    The non-required-charge discharge portions 11 are n-type semiconductor portions formed on the second semiconductor portion 5 and having a high impurity concentration. The non-required charge discharge sections 11 discharge the charges generated in the charge generating section as unnecessary charges. The non-required charge discharge portions 11 have a rectangular shape in a plan view. In the present embodiment, the non-required charge discharge portions 11 have a square shape in a plan view. The non-required charge discharge sections 11 are connected, for example, to a fixed potential Vdd.
    Each of the third transfer electrodes TX3 is provided on the insulating layer 7 and between the photogate electrode PG and a corresponding one of the non-required-charge discharge sections 11. The third transfer electrodes. TX3 are disposed away from the non-required charge discharge portions 11 and the photogate electrode PG. In accordance with the third transfer signal STX3, the third transfer electrodes TX3 allow the charges generated in the charge generation section to flow as unnecessary charges to the non-required charge discharge sections 11. The third transfer electrodes TX3 have a rectangular shape in a plan view. In the present embodiment, the third transfer electrodes TX3 have an elongated shape with a long side edge direction set in the direction in which the first and second short sides S1 and S2 of the photogate electrode PG face each other. The lengths in the long side edge direction of the third transfer electrodes TX3 are set to the same lengths as the lengths in the long side edge direction of the first and second transfer electrodes TX1 and TX2.
    The insulating layer 7 is provided with contact holes to expose the surface of the second semiconductor portion 5. The electric conductors 13 are disposed in the contact holes to connect the first and second signal collection sections 9a and 9b and the non-required charge discharge sections 11 to the outside.
    For example, in the present embodiment, a "high impurity concentration" means an impurity concentration of about 1 × 10 17 cm -3 or more, and is indicated by a "+" added to a conductivity type. For example, a "low impurity concentration" means an impurity concentration of about 10 × 10 15 cm -3 or less, and is indicated by a "-" added to a conductivity type.
    An example of a thickness / impurity concentration of each semiconductor portion is as follows.
    First semiconductor section 4: Thickness 10 to 1000 pm / impurity concentration 1 x 10 12 to 10 19 cm -3 Second semiconductor section 5: Thickness 1 to 50 pm / impurity concentration 1 x 10 12 to 10 15 cm -3 First and second Signal charge collection sections 9a and 9b:
    Thickness 0.1 to 1 pm / impurity concentration 1 x 1018 to 1020 cm-3 Unnecessary charge discharge sections 11:
    Thickness 0.1 to 1 pm / impurity concentration 1 x 1018 to 1020 cm-3 A reference potential, such as a ground potential, is transmitted to the semiconductor substrate 2 (the first and second semiconductor portions 4 and 5) via a back gate a through-via electrode or the like. The semiconductor substrate is made of Si, the insulating layer is of SiO 2, and the photo gate electrode PG and the first to third transfer electrodes TX 1, TX 2, and TX 3 are made of polysilicon, but may be made of other materials.
    The phase of the first transfer signal STX1 applied to the first transfer electrodes TX1 and the phase of the second transfer signal STX2 applied to the second transfer electrodes TX2 are different in phase from each other. In the present embodiment, the phase of the first transfer signal STX1 and the phase of the second transfer signal STX2 are shifted by 180 degrees, for example. The phase of the third transfer signal STX3 applied to the third transfer electrodes TX3 is different from the phases of the first and second transfer signals STX1 and STX2. In the present embodiment, the phase of the third transfer signal STX3 is opposite to the phases of the first and second transfer signals STX1 and STX2. That is, the third transfer signal STX3 is small when the first or second transfer signal STX1 or STX2 is high, and the third transfer signal STX3 is high when the first or second transfer signal STX1 or STX2 is low.
    The light incident in each range finding sensor P is converted into charges in the semiconductor substrate 2 (the second semiconductor portion 5). A part of the converted charges moves, as the signal charges, in a direction of the first transfer electrodes TX1 or the second transfer electrodes TX2, i. in a direction parallel to the first and second short side edges S1 and S2 of the photogate electrode PG, in accordance with a potential gradient formed by a voltage applied to the photogate electrode PG and the first and second transfer electrodes TX1 and TX2 becomes.
    When a positive potential is supplied to the first or second transfer electrodes TX1 or TX2, a potential below the first or second transfer electrodes TX1 or TX2 with respect to electrodes becomes lower than a potential in a portion of the semiconductor substrate 2 (the second semiconductor portion 5 ) located below the photogate electrode PG. Negative charges (electrons) are therefore drawn toward the first or second transfer electrodes TX1 or TX2, and accumulated and accumulated in a potential trench formed by the first and second signal charge collection sections 9a and 9b. An n-type semiconductor contains a positively ionized donor and has a positive potential for attracting electrons. When a potential (for example, ground potential) lower than the positive potential described above is supplied to the first or second transfer electrodes TX1 or TX2, a potential barrier is generated by the first or second transfer electrodes TX1 or TX2. Therefore, the charges generated on the semiconductor substrate 2 are not drawn into the first and second signal charge collection sections 9a and 9b.
    A part of the charges generated by a light incident in each ranging sensor P moves as the unnecessary charges in the direction of the third transfer electrodes TX3, according to a potential gradient formed by a voltage applied to the photogate. Electrode PG and the third transfer electrode TX3 is applied.
    When a positive potential is supplied to the third transfer electrodes TX3, a potential below the third transfer electrodes TX3 becomes lower than the potential in the portion of the semiconductor substrate 2 (the second semiconductor portion 5) located below the photogate electrode PG. Negative charges (electrons) are therefore drawn toward the third transfer electrodes TX3 and collected in a potential trench formed by the non-erosion-charge discharge sections 11, and are then discharged. When a potential (for example, ground potential) that is lower than the positive potential described above is applied to the third transfer electrodes TX3, a potential barrier is generated by the third transfer electrodes TX3, and the charges generated on the semiconductor substrate 2 will not be transferred to the non-negative. Required charge discharge sections 11 pulled.
    Figs. 6 and 7 are diagrams each showing a potential profile in the vicinity of the second main surface of the semiconductor substrate. FIG. 6 is a diagram illustrating a collection operation (accumulation operation) of the signal charges. FIG. Fig. 7 is a diagram illustrating a discharge operation of unnecessary charges. FIGS. 6 (a), 6 (b) and 7 (a) show potential profiles in the vicinity of the second main surface 2b of the semiconductor substrate 2 along the line IV-IV shown in FIG. FIGS. 6 (c) and 7 (b) show potential profiles in the vicinity of the second main surface 2b of the semiconductor substrate 2 along the line V-V shown in FIG.
    6 and 7 show a potential φ ™ in a portion immediately below the first transfer electrodes TX1, a potential φτχ2 in a portion immediately below the second transfer electrode TX2, a potential φτχ3 in a portion immediately below the third transfer electrode TX3, a potential <pPG in a charge generation section immediately below the photogate electrode PG, a potential <pFDi in the first signal charge collection sections 9a, a potential <pFD2 in the second signal charge collection sections 9b and potential <pofdi, and <Pofd2 in the non-required one Charge Discharge Portions 11. In Figs. 6 and 7, a downward direction corresponds to a positive direction of the potentials.
    When the potentials φτχι, φτχ> and φυα in the portions immediately below the adjacent first to third transfer electrodes TX1 to TX3 are defined as reference potentials without a bias voltage, the potential <pPG in the portion (charge generation portion) is immediately below Photogate electrode PG set higher than the reference potentials. When light is incident, it means that the potential <ppg in the portion immediately below the photogate electrode PG is set slightly higher than a substrate potential due to a potential supplied to the photogate electrode PG (for example, an intermediate potential between one higher potential and lower potential supplied to the first transfer electrodes TX1). The potential <pPG in the charge generation section is higher than the potentials φτχι, φτχ2, and φτχ3. The potential profile has a shape that is recessed downward in the drawings in the charge generating section.
    The collection operation (accumulation operation of the signal charges will be explained with reference to FIG. 6.
    When the phase of the first transfer signal STX1 applied to the first transfer electrodes TX1 is 0 degrees, a positive potential is supplied to the first transfer electrodes TX1. An inverse phase potential, i. a potential having a phase of 180 degrees (for example, ground potential) is supplied to the second transfer electrodes TX2. An intermediate potential between the potential supplied to the first transfer electrodes TX1 and the potential supplied to the second transfer electrodes TX2 is supplied to the photogate electrode PG. In this case, the potential φΤΧι in the semiconductor immediately below the first transfer electrodes TX1 as shown in Fig. 6 (a) becomes lower than the potential <ppg in the charge generating portion, and a negative charge e generated in the charge generation portion. therefore flows into the potential trench of the first signal charge collecting sections 9a.
    The potential φτχ2 in the semiconductor region immediately below the second transfer electrodes TX2 does not become lower and the charge does not flow into the potential trench of the second signal charge collecting sections 9b. The signal charges are therefore accumulated and accumulated in the potential trench of the first signal charge collection section 9a. Since the first and second signal charge collecting sections 9a and 9b are doped with n-type impurities, the potentials are recessed in the positive direction.
    When the phase of the second transfer signal STX2 applied to the second transfer electrodes TX2 is 0 degrees, a positive potential is supplied to the second transfer electrodes TX2, and an inverse phase potential, i. A potential having a phase of 180 degrees (for example, ground potential) is supplied to the first transfer electrodes TX1. An intermediate potential between the potential supplied to the first transfer electrodes TX1 and the potential supplied to the second transfer electrodes TX2 is given to the photogate electrode PG. The potential φτχ2 in the semiconductor immediately below the second transfer electrodes TX2 in this case, as shown in Fig. 6 (b), becomes lower than the potential <pPG in the charge generation section, and a negative charge e generated in the charge generation section. therefore, flows into the potential trench of the second signal charge collecting sections 9b.
    The potential φτχι of the semiconductor region immediately below the first transfer electrodes TX1 therefore does not decrease, and the charge does not flow into the potential trench of the first signal charge collection sections 9a. The signal charges are therefore accumulated and accumulated in the potential trench of the second signal charge collecting sections 9b.
    While the first and second transfer signals STX1 and STX2 whose phases are shifted from each other by 180 degrees are applied to the first and second transfer electrodes TX1 and TX2, the ground potential is supplied to the third transfer electrodes TX3. As shown in Fig. 6 (c), therefore, the potential <prx3 of the semiconductor immediately below the third transfer electrodes TX3 does not become lower, and the charge does not flow into the potential trenches of the non-required charge discharge portions 11.
    In this way, the signal charges in the potential trenches of the first and second signal charge collecting sections 9a and 9b are accumulated and accumulated. The signal charges accumulated in the potential trenches of the first and second signal charge collection sections 9a and 9b are read out to the outside.
    The discharging operation of unnecessary charges will be explained with reference to FIG. 7.
    The ground potential is supplied to the first and second transfer electrodes TX1 and TX2. As shown in Fig. 7 (a), therefore, the potentials φΤχι and φΤχ2 in the semiconductor regions immediately below the first and second transfer electrodes TX1 and TX2 do not become lower, and the charge does not flow into the potential trenches of the first and second signal charge collection sections 9a and 9b 9b. A positive potential is supplied to the third transfer electrodes TX3. In this case, the potential φΤχ3 in the semiconductor region immediately below the third transfer electrodes TX3, as shown in Fig. 7 (b), becomes lower than the potential (pPG in the charge generating portion and a negative charge e generated in the charge generating portion. Therefore, it flows into the potential trenches of the non-discharging-charge discharging sections 11. In this way, the unnecessary charges are accumulated in the potential trenches of the non-required-discharging discharge sections 11. The potentials included in the potential ditches of the non-required discharging sections 11 are shown in FIG. Charge discharge sections 11 accumulated unnecessary charges are discharged to the outside.
    A method of calculating the distance d will now be explained with reference to FIG. 8. Fig. 8 is a timing chart of various signals. Fig. 3 shows various signals in a period in which the signal charges are accumulated and accumulated (accumulation period). The frame period includes a period in which the signal charges are read out (read-out period) in addition to the accumulation period.
    8 shows the driving signal SD of the light source, an intensity signal SP of the reflected light Lr which can be obtained when the reflected light Lr is incident on the ranging image sensor RS, the first transfer signal STX1 applied to the first transfer electrodes TX1, and the second transfer signal STX2 applied to the second transfer electrodes TX2. The drive signal Sd, the intensity signal SP, the first transfer signal STX1, and the second transfer signal STX2 are each pulse signals having a pulse width Tp.
    In the accumulation period, upon application of the drive signal SD to the light source LS, in synchronization with the application of the drive signal SD, the first and second transfer signals STX1 and STX2 are applied to the first and second transfer electrodes TX1 and TX2 with phases opposite to each other , In the present embodiment, in an accumulation period, the drive signal SD is applied twice at the light source LS, and the first and second transfer signals STX1 and STX2 are applied to the first and second transfer electrodes TX1 and TX2 each time the drive signal Sd is applied. By applying the first and second transfer signals STX1 and STX2 to the first and second transfer electrodes TX1 and TX2, charge transfer is performed, and the signal charges are accumulated in the first and second signal charge collection sections 9a and 9b. That is, the drive signal SD and the first and second transfer signals STX1 and STX2 are sequentially applied in a time series, and the accumulation operation (accumulation operation) of the signal charges is also successively performed in time series. In the readout period, the signal charges accumulated in the first and second signal charge collection sections 9a and 9b are then read out.
    The output control of the first and second transfer signals STX1 and STX2 is executed by the control unit CONT. In synchronization with the emission of the pulse light Lp, the control unit CONT outputs the first transfer signal STX1 to the first transfer electrodes TX1 so that the charges generated in the charge generation section can flow as signal charges to the first signal charge collection sections 9a, and outputs the second transfer signal STX2 to the first transfer signal TX1 second transfer electrodes TX2, so that the charges generated in the charge generating section can flow as the signal charges into the second signal charge collecting sections 9b.
    The charge quantity Qi corresponding to an overlap period of the intensity signal SP and the first transfer signal STX1 output in synchronism with the drive signal Sd at a phase difference O is accumulated in the first signal charge collection sections 9a. The charge quantity Q2 corresponding to an overlap period of the intensity signal SP and the second transfer signal STX2 output in synchronism with the drive signal SD at a phase difference of 180 is accumulated in the second signal charge collection sections 9b.
    A phase difference Td between the intensity signal SP and a signal output in synchronism with the drive signal Sd at a phase difference of 0 corresponds to a time of flight of the light. The phase difference Td indicates the distance d from the ranging image sensor RS to the object OJ. The distance d is calculated by the arithmetic unit ART according to the following equation (1) using a ratio between a total charge quantity Qn of the charge quantities Qi accumulated in subsequent time series and a total charge quantity Qj2 of charge quantities Q2. In addition, c draws a speed of light.
    Distance d = (c / 2) x (Tp x Gt2 / (QTi + Or2)) That is, the arithmetic unit ART satisfies the respective charge quantities Οί and Q2 in the first and second Read charge accumulation collecting sections 9a and 9b accumulated signal charges, and calculates the distance d to the object OJ based on the read-out charge quantities Qi and Q2. The arithmetic unit ART here calculates the distance d to the object OJ based on the total charges Qn and QT2 of the signal charges successively accumulated in time series in the first signal charge collection sections 9a and the second signal charge collection sections 9b.
    Hereinafter, a selecting operation of pixels (channels: ch) formed by the respective ranging sensors P will be explained with reference to FIGS. 9 and 10. FIG. Fig. 9 is a diagram showing a relationship between a timing chart of various signals and a pixel to be selected. Fig. 10 is a diagram illustrating a relationship between a movement of a reflection element and a pixel.
    Signals applied in pixels (channels I to 5ch) formed by the respective ranging sensors P of the ranging image sensor RS, i. E. the first to third signals STX1, STX2 and STX3 are shown together with the drive signal Sd in Fig. 9 (a). The range finding sensors P (channels I to 5ch) to which the reflected light Lr is incident as a result of scanning an irradiation position on the object OJ of the pulse light Lp are indicated in Fig. 9 (b) as portions indicated by bold surrounded by printed lines. In the present embodiment, as shown in FIG. 10, scanning of the irradiation position on the object OJ of the pulse light Lp is repeated such that the reflected light Lr sequentially enters the channels Ich to 5ch in that order, and then the reflected light Lr into the channels 5ch until I invade sequentially in that order.
    In the present embodiment, as shown in Fig. 10 (a), scanning of the irradiation position on the object OJ of the pulsed light Lp is repeated such that the reflected light Lr is sequentially incident on the channels I to 5ch in this order, and then the reflected light Lr into the channels 5ch until I sequentially invade in that order. Fig. 10 (a) schematically shows the movement of the reflection element MR as a line diagram. Fig. 10 (b) shows the range finding sensors P (channels I to 5ch) in which the reflected light Lr is incident, in time series, as dashed lines
    Sections. Fig. 10 (b) shows range finding sensors P (channels I to 5ch) from which the total charge quantities Q-π and Qt2 are read, in c time series as portions surrounded by bold lines.
    The pixels (channels I to 5ch) into which the reflected light Lr is incident vary according to the irradiation position on the object OJ of the pulse light Lp. For example, as shown in Fig. 9 (b), when the reflected light Lr is incident on the distance measuring sensor P forming the pixel corresponding to the channel Ich, the selecting unit SEL outputs the first to third transfer signals STX1, STX2 and STX3 to the distance measuring sensor P is such that the above-described collection operation (accumulation operation) of the signal charges is carried out in the range finding sensor P which forms the pixel corresponding to the channel Ich. For example, when the reflected light Lr is incident on the distance measuring sensor P forming the pixel corresponding to the channel 5ch, the selecting unit SEL outputs the first to third transfer signals STX1, STX2 and STX3 to the distance measuring sensor P such that the above-described collection operation (accumulation operation ) of the signal charges in the ranging sensor P which forms the pixel corresponding to the channel 5ch. That is, the selecting unit SEL of the plurality of pixels (channels I to 5ch) selects the pixel from which the signals are to be read out according to the irradiation position on the object OJ of the pulse light Lp.
    The arithmetic unit ART reads out signals from the pixel selected by the selecting unit SEL and calculates the distance to the object OJ for each pixel. In the present embodiment, the arithmetic unit ART performs collective readout of the signal charges generated by reciprocation of the scanning, that is, reciprocation. the signal charges generated by the reflected light Lr being incident twice on the ranging sensors P, forming the pixels corresponding to the respective channels I to 5ch twice, and generated by the occurrence of the reflected light Lr twice. The arithmetic unit ART therefore reads out two total charge quantities Qu and QT2 in a readout period.
    The selecting unit SEL outputs the first to third transfer signals STX1, STX2 and STX3 to the distance measuring sensor P so as to perform the above-described discharging operation of the unnecessary charges in the distance measuring sensor P constituting the pixels (channels I to 5ch) into which the reflected light Lr does not fall. That is, in the range finding sensor P in which the reflected light Lr is not incident, the generated charges are discharged so that the charges do not accumulate.
    In this way, the selecting unit SEL (the control unit CONT) in the present embodiment outputs the first transfer signal STX1 to the first transfer electrodes TX1 of the distance measuring sensor P, which outputs the pixels (channels I to 5ch) corresponding to the irradiation position of the pulse light Lp is formed so that the signal charges can flow into the first signal charge collection sections 9a of the distance measurement sensor P. The selection unit SEL outputs the second transfer signal STX2 to the second transfer electrodes TX2 of the above-described range finding sensor P in accordance with the irradiation position of the pulse light Lp, so that the signal charges can flow into the second signal charge collection portions 9b of the range finding sensor P. That is, the charges which are generated in the charge generation section (the portion located below the photogate electrode PG) of the range finding sensor P selected by the selection unit SEL are applied to the first signal charge collection sections 9a and the second signal charge collection sections 9b as the signal charges are distributed, and the signal charges are accumulated in the respective sections 9a and 9b.
    The selection unit SEL (the control unit CONT) outputs the third transfer signal STX3 to the third transfer electrodes TX3 of the range finding sensor P except for the above-described range finding sensor P corresponding to an irradiation position of the pulse light Lp, so that unnecessary charges are not required Charge discharge sections 11 of the distance measurement sensor P can flow. That is, in the ranging sensor P other than the ranging sensor P in which the signal charges are collected, the charges generated in the charge generation section (the portion located below the photogate electrode PG) of the range finding sensor P are from the non-required charges -Discharge section 11 are discharged as unnecessary charges. The arithmetic unit ART reads out signals corresponding to the respective magnitudes of the signal charges collected in the first and second signal charge collecting sections 9a and 9b of the range finding sensor P selected by the selecting unit SEL, and calculates the distance to the object OJ based on the relationship between the Size of the number of signal charges accumulated in the first signal charge collection sections 9a and the number of signal charges accumulated in the second signal charge collection sections 9b.
    In the distance measuring sensor P except for the distance measuring sensor P in which the signal charges are collected, the charges generated in the charge generating portion (the portion located below the photogate electrode PG) of the distance measuring sensor P become against this background discharged as unnecessary charges. Therefore, a charge amount based on unnecessary charges can be reproduced with difficulty in calculating the distance to the object OJ. The distance measuring device 1 can therefore measure the distance properly and accurately. According to the distance measuring apparatus 1, a distance measurement image having a suppressed motion distortion can be obtained even if the object OJ is a movable body.
    Hereinafter, a modified example of the present embodiment will be described with reference to FIGS. 11 and 12. 11 is a diagram illustrating a relationship between a timing chart of various signals and a pixel to be selected according to this modified example. Fig. 12 is a diagram showing a relationship between a movement of a reflection element and a pixel according to this modified example.
    In Fig. 11 (a), similar to Fig. 9 (a), the first to third transfer signals STX1, STX2 and STX3 applied in pixels (channels I to 5ch) are determined by the respective ranging sensors P are formed, shown together with the driver signal SD. In Fig. 11 (b), similar to Fig. 9 (b), the range finding sensors P (channels Ich to 5ch) into which the reflected light Lr is incident due to the scanning of the pulse light Lp are shown as portions indicated by bold lines are surrounded. Also in this modified example, as shown in Fig. 12, scanning of the irradiation position on the object OJ of the pulse light Lp is repeated such that the reflected light Lr sequentially enters the channels I to 5ch in this order, and then the reflected light Lr into the channels 5ch until I sequentially invade in this order.
    Also in this modified example, as shown in Fig. 12 (a), scanning of the irradiation position on the object OJ of the pulse light LP is repeated such that the reflected light Lr is sequentially input to the channels I to 5ch in this order, and then the reflected light Lr into the channels 5ch until I sequentially invade in that order. Similar to Fig. 10 (a), Fig. 12 (a) schematically shows the movement of the reflection element MR as a line diagram. Fig. 12 (b) shows the range finding sensors P (channels I to 5ch) in which the reflected light Lr is incident, in time series as broken portions. Fig. 12 (b) shows range finding sensors P (channels I to 5ch) from which charge quantities at times when the reflected light Lr is not incident are read out in time series as portions surrounded by bold lines.
    For example, as shown in Fig. 11 (b), when the reflected light LR is incident on the distance measurement sensor P forming the pixel corresponding to the channel Ich, the selecting unit SEL outputs the first to third transfer signals STX1, STX2 and STX3 to the range finding sensor P such that the above-described collection operation (accumulation operation) of the signal charges is carried out in the range finding sensor P forming the pixel corresponding to the channel Ich.
    Before the collection operation of the signal charges, at a time when the reflected light Lr does not enter the distance measuring sensor P forming the pixel corresponding to the channel Ich, the selecting unit SEL indicates the first to third transfer signals STX1, STX2 and STX3 the range finding sensor P such that the collection operation (accumulation operation) of the charges is carried out. The timing at which the reflected light Lr does not enter the distance measuring sensor P forming the pixel corresponding to the channel Ich corresponds to a timing at which the pulse light Lp is not emitted to the irradiation position at which the reflected light Lr enters the range finding sensor P incident. The charges which are collected at a time when the reflected light Lr is not incident are charges generated by a backlight or an ambient light, such as a part of the reflected light Lr incident to the range finding sensors P which form the pixels corresponding to other channels 2ch through 5ch, and are noise components for the signal charges.
    The selector SEL similarly outputs the first to third transfer signals STX1, STX2 and STX3 to respective ranging sensors P of the channels 2ch to 5ch other than the channel I to carry out the collection operation of the signal charges, and the collection operation of the charges before the Collection operation of the signal charges is performed. The charges accumulated by the collecting operation before the collecting operation of the signal charges are collected in the first signal charge collecting sections 9a and the second signal charge collecting sections 9b similarly to the signal charges. The timings at which the reflected light Lr is incident on the range finding sensors P forming the pixels corresponding to the respective channels Ich to 5ch are times other than a timing at which the signal charges into the first signal charge collecting sections 9a and 9b can flow.
    The arithmetic unit ART reads out signals from the pixel selected by the selection unit SEL and calculates the distance to the object OJ for each pixel. In this modified example, the arithmetic unit ART reads, for each of the range finding sensors P which form the pixels corresponding to the respective channels I to 5ch, charge quantities 0- and Q2 based on the collection operation of signal charges and charge quantities on the collection operation of charges carried out prior to the collection operation of signal charges. The arithmetic unit ART calculates the distance to the object OJ based on a ratio between a charge quantity (Qiqi) obtained by subtracting a charge quantity q · which is collected in the first signal charge collection sections 9a by the collection operation of the charges the collection operation of the signal charges is carried out, the charge quantity Q-ι based on the collection operation of the signal charges, and a charge quantity (Q2-q2) obtained by subtracting a charge quantity q2 in the second signal charge collection sections 9b through the signal charge Collecting operation of the charges performed before the collection operation of the signal charges, of the charge quantity Q2 based on the collection operation of the signal charges.
    Also in this modified example, the selecting unit SEL outputs the first to third transfer signals STX1, STX2 and STX3 so as to carry out the above-described discharge operation of unnecessary charges in distance measuring sensors P, except for the distance measuring sensor P having the above-described Collecting operation of charges before the collecting operation of signal charges, from distance measuring sensors P forming pixels (channels I to 5ch) into which the reflected light Lr is not incident to the distance measuring sensors P. In the range finding sensors P into which the reflected light Lr does not and that do not perform the collection operation of the charges before the collection operation of the signal charges, the generated charges are discharged so that the charges do not accumulate.
    In this modified example, the selection unit SEL (the control unit CONT) in the selected distance measurement sensor P outputs the first transfer signal STX1 to the first transfer electrodes TX1 of the distance measurement sensor P so that the charges can flow into the first signal charge collection sections 9a the influence of the signal charges on the first and second signal charge collecting sections 9a and 9b at a time when the pulse light Lp is not emitted from the light source Ls. In the selected range finding sensor P described above, the selecting unit SEL outputs the second transfer signal STX2 to the second transfer electrodes TX2 of the distance measuring sensor P so that the charges can flow into the second signal charge collecting sections 9b, before the influence of the signal charges on the first and the first second signal charge collecting sections 9a and 9b at a time when the pulse light is not emitted from the light source Ls. That is, in the charge generating portion (the portion located below the photogate electrode PG) of the range finding sensor P selected by the selecting unit SEL, the charges not generated by the emission of the pulse light Lp corresponding to the distance measuring sensor P, are distributed into the first signal charge collection sections 9a and the second signal charge collection sections 9b and collected in the respective sections 9a and 9b.
    The arithmetic unit ART calculates a distance to the object OJ based on a relationship between a quantity (Qiq) of signal charges collected in the first signal charge collection sections 9a obtained by subtracting a quantity q of charges accumulated in the first signal charge collecting sections 9a at a time when the pulse light Lp is not emitted from the light source Ls, and a magnitude (Q2-q2) of signal charges applied to the second signal charge Collection portions 9b obtained by subtracting a quantity q2 from charges collected in the second signal charge collection portions 9b at a time when the pulse light Lp is not emitted from the light source Ls. In other words, by subtracting charges which are not generated by the emission of the pulse light Lp corresponding to the selected range finding sensor P, a charge amount based on the above-described ambient light is difficult to reproduce in the calculation of the distance to the object OJ. In this modified example, therefore, the distance measurement can be performed better and more accurately.
    The embodiment of the present invention and the modified example of the embodiment have been explained above. However, the present invention is not necessarily limited to the embodiment described above, and various changes can be made without departing from the scope of the present invention.
    In the above-described embodiment and the modified example, each ranging sensor P includes, for example, a pair of first signal charge collection sections 9a, second signal charge collection sections 9b, non-required charge discharge sections 11, first transfer electrodes TX1, second transfer electrodes TX2 and third transfer electrodes TX3. The number of first signal charge collection sections 9a, second signal charge collection sections 9b, non-required charge discharge sections 11, and first to third transfer electrodes TX1, TX2, and TX3 included in each range finding sensor P is not limited thereto. The number of first signal charge collection sections 9a, second signal charge collection sections 9b, non-required charge discharge sections 11 and first to third transfer electrodes TX1, TX2 and TX3 included in each range finding sensor P may be one, three or more , The number of range finding sensors P included in the ranging image sensor RS is not limited to five and only required to be in the plurality. In the present embodiment and this modified example, the number of pixels (ranging sensors P) selected by the selecting unit SEL is one. However, the number may be two or more.
    In the present embodiment and this modified example, the light path of the pulse light Lp emitted from the light source LS is changed by using the reflection element MR, and the irradiation position on the object OJ of the pulse light Lp is scanned. However, the configuration is not limited to this. The irradiation position on the object OJ of the pulse light Lp can be scanned by moving the light source LS without using the reflection element MR.
    In this modified example, the selecting unit SEL (the control unit CONT) outputs the first and second transfer signals STX1 and STX2 so that the charges can flow into the first and second signal charge collecting sections 9a and 9b, before the influence of the Signal charges in the first and second signal charge collecting sections 9a and 9b, at a time when the pulse light Lp is not emitted from the light source. The configuration
    权利要求:
    Claims (2)
    [1]
    but is not limited to this. The selecting unit SEL (the control unit CONT) can output the first and second transfer signals STX1 and STX2 so that the charges can flow into the first and second signal charge collecting sections 9a and 9b, according to the influence of the signal charges on the first and second signal charges And a timing at which the pulse light Lp is not emitted from the light source LS. In the present embodiment, in each ranging sensor P, the amounts of charge collected by two collection operations (accumulation operations) are continuously read out in time series. However, the configuration is not limited to this. In each ranging sensor P, the charge quantity can be continuously selected in time series collected by three or more collection operations (accumulation operations). In this way, the size of the accumulated charges is also increased in accordance with the increase in the number of collection operations, so that a sufficient signal size is ensured. The sufficient signal size is of course ensured by the charge size, which is collected in two collection operations. The range finding image sensor RS is not limited to a line sensor in which the plurality of range finding sensors P are arranged one-dimensionally. The range finding image sensor RS may be a line sensor in which the plurality of range finding sensors P are two-dimensionally arranged. In this case, a two-dimensional image can be easily obtained. The ranging image sensor RS is not limited to a front-mounted ranging image sensor. The ranging image sensor RS may be a back-illuminated ranging image sensor. A charge generating section that generates the charges in accordance with a light incident may include a photodiode (for example, an embedded photodiode). The p-type and n-type conductivity types in the distance-measuring image sensor RS according to the present embodiment can be mutually replaced so that the one given in the above description is inverted. Industrial Applicability The present invention can be used in a distance measuring apparatus for measuring a distance to an object. List of Reference Numerals [0099] FIG. 1: Distance measuring device, 9a: first signal charge collecting section, 9b: second signal charge collecting section, 11: non-required charge discharge section, A: one-dimensional direction, ART: arithmetic unit, CONT: control unit, DRV: drive unit , Lp: pulsed light, Lr: reflected light, LS: light source, MR: reflective element, OJ: object, P: distance sensor, PG: photogate electrode, Pi: irradiation position, RS: range image sensor, SEL: selector, STX1: first transfer signal , STX2: second transfer signal, STX3: third transfer signal, TX1: first transfer electrode, TX2: second transfer electrode, TX3: third transfer electrode. claims
    A distance measuring apparatus comprising: a light source (LS) for emitting light in the direction of an object (OJ); a scanning unit including a driving unit (DRV) for driving the light source (LS), the scanning unit scanning an irradiation position on the object by means of pulse light emitted from the light source; a light receiving unit (RS) having a plurality of pixels arranged in a one-dimensional direction and incident upon the reflected light of the pulse light reflected from the object (OJ); a selection unit (SEL) for selecting, among the plurality of pixels, a pixel from which a signal is to be read, in accordance with the irradiation position of the pulse light sampled by the scanning unit; and an arithmetic unit (ART) for reading a signal from the pixel selected by the selecting unit (SEL) and calculating a distance (d) to the object (OJ), wherein each of the plurality of pixels includes: a charge generating portion for generating charges in accordance with an incident light; first and second signal charge collecting sections (9a, 9b) disposed away from the charge generating section and for collecting the charges generated in the charge generating section as signal charges; a non-required charge discharge section (11) located away from the charge generation section and for discharging the charges generated in the charge generation section as unnecessary charges; a first transfer electrode (TX1) disposed between the first signal charge collecting section (9a) and the charge generating section, and for allowing the charges generated in the charge generating section to flow into the first signal charge collecting section (9a) as the signal charges, in accordance with a first transfer signal; a second transfer electrode (TX2) disposed between the second signal charge collecting section (9b) and the charge generating section, and for allowing the charges generated in the charge generating section to flow into the second signal charge collecting section (9b) as the signal charges, Correspondence with a second transfer signal that differs in one phase from the first transfer signal; and a third transfer electrode (TX3) disposed between the non-required charge discharge section (11) and the charge generation section, and for allowing the charges generated in the charge generation section to be transferred to the non-required charge discharge section (11). as the unnecessary charges can flow in accordance with a third transfer signal different in phase from the first and second transfer signals, wherein, in accordance with an irradiation position of the pulse light sampled by the scanning unit, the selection unit (SEL) receives the first transfer signal outputs to the first transfer electrode (TX1) and outputs the second transfer signal to the second transfer electrode (TX2) to allow the signal charges to flow into the first and second signal charge collection sections (9a, 9b) of the selected pixel according to the irradiation position; among the multitude of pixels n, and outputs the third transfer signal to the third transfer electrode (TX3) to allow the unnecessary charges to flow into the non-required charge discharge portion (11) of the pixels except for the pixel corresponding to the irradiation position; among the plurality of pixels, and wherein the arithmetic unit (ART) reads out signals corresponding to respective magnitudes of the signal charges accumulated in the first and second signal charge collecting sections (9a, 9b) of the pixel selected by the selecting unit (SEL), and a distance (d) to the object (OJ) based on a relation between the size of the signal charges collected in the first signal charge collecting section (9a) and the magnitude of the signal charges collected in the second signal charge collecting section (9b). , calculated.
    [2]
    A distance measuring apparatus according to claim 1, wherein said selecting unit (SEL) is adapted to output, with respect to the selected pixel, the first transfer signal to the first transfer electrode (TX1) and to output the second transfer signal to the second transfer electrode (TX2) allow charges to flow into the first and second signal charge collecting sections (9a, 9b) at a timing different from a timing at which the signal charges can flow into the first and second signal charge collecting sections (9a, 9b), and which is a timing at which the pulse light is not emitted from the light source, and wherein the arithmetic unit calculates a distance to the object based on a ratio between a magnitude of signal charges collected in the first signal charge collecting section (9a) is obtained by subtracting a quantity of collected in the first signal charge collecting section (9a) Charges at the time when the pulse light is not emitted from the light source (LS), signal charges accumulated in the first signal charge collection section (9a), and a magnitude of signal charges collected in the second signal charge collection section (9b) which is obtained by subtracting a magnitude of charges accumulated in the second signal charge collecting section (9b) at the time when the pulse light is not emitted from the light source (LS) from signal charges accumulated in the second signal charge collecting section (9b) ,
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    同族专利:
    公开号 | 公开日
    JP6386798B2|2018-09-05|
    KR20170015941A|2017-02-10|
    US20170115392A1|2017-04-27|
    KR102291769B1|2021-08-23|
    CN106461781A|2017-02-22|
    US11054522B2|2021-07-06|
    WO2015190308A1|2015-12-17|
    CN106461781B|2020-04-14|
    JP2015232452A|2015-12-24|
    DE112015002711T5|2017-02-23|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    JP2014118623A|JP6386798B2|2014-06-09|2014-06-09|Ranging device|
    PCT/JP2015/065458|WO2015190308A1|2014-06-09|2015-05-28|Distance measuring device|
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