JP5266636B2 - Optical sensor and distance detection device - Google Patents

Description

The present invention relates to a distance detection equipment using an optical sensor and the light sensor, is used to measure the distance to the object to be the measuring object.

  2. Description of the Related Art Conventionally, a distance detection device that measures a distance to an object using a CMOS photosensor array having a large number of photosensors is known. In this device, the distance from the light source is received by the photodiode in each optical sensor, and the time until the reflected light from the object corresponding to the projected light is received is measured, thereby measuring the distance to the object. To do.

More specifically, each photosensor includes two charge storage units per pixel, and one charge storage unit stores charges generated by the photodiode when the light source is projecting light. The other charge storage unit stores the charge generated by the photodiode when the light source is not projecting light. Then, by comparing the amount of charge stored in each charge storage unit using an arithmetic unit, it is possible to calculate the time until the reflected light from the object is received, that is, the distance to the object (for example, , See Patent Document 1).
International Publication No. 2004/012269 Pamphlet

  However, an optical sensor that does not have a distance measurement function and has only an image identification function requires one charge storage unit, whereas the optical sensor requires two charge storage units. There is a problem that the integration rate of the circuit deteriorates by the amount of the storage unit.

  Accordingly, in view of such a problem, an object of the present invention is to improve the integration rate of an optical sensor in an optical sensor used when measuring a distance to an object to be measured. .

The optical sensor according to claim 1, wherein the optical sensor is used to measure the distance to the object to be measured, and includes one of a pair of light detection units. A pair of first transfer elements that transfer charges to the charge storage unit, and a pair of second transfer elements that transfer charge from the pair of photodetection units to the other charge storage unit. In addition, the charge storage unit, the light detection unit, the reset element, the first transfer element, the second transfer element, and the output element that constitute the photosensor are arranged on the substrate, and each charge storage unit is arranged on the substrate. Are arranged symmetrically with respect to each photo detector.

  Here, in the optical sensor used when measuring the distance to the object to be measured, it is necessary to distribute the charge generated by the light detection unit to a plurality of charge storage units according to the light reception timing. For this reason, in the conventional optical sensor, one charge detection unit is provided with two charge storage units. However, the optical sensor of the present invention includes a first transfer element and a second transfer element. Therefore, it is only necessary to provide one charge storage unit for one photodetection unit.

Therefore, according to the optical sensor of the present invention, the optical sensor can be reduced in size as compared with an optical sensor having two charge storage units for one optical detection unit as in the conventional optical sensor. Therefore, the integration rate of the optical sensor can be improved.
In the photosensor of the present invention, the first transfer element includes a first transfer unit that transfers charges from one photodetection unit to one charge storage unit, and one charge storage unit from the other photodetection unit. A second transfer unit that transfers charge to the second transfer element, the second transfer element includes a third transfer unit that transfers charge from one photodetection unit to the other charge storage unit, and the other photodetection unit to the other A fourth transfer unit that transfers the charge to the charge storage unit; The second transfer unit and the third transfer unit are configured to transfer the charge to the first transfer unit while prohibiting the second transfer unit and the third transfer unit from transferring the charge in a state where the charge of each charge storage unit is reset by the reset element, and The operation of transferring the charge to the third transfer unit at different timings while prohibiting the transfer of the charge by the first transfer unit and the fourth transfer unit is performed at different timings, and then the charge of each charge storage unit is reset by the reset element. In the state, the operation of transferring the charge to the second transfer unit while prohibiting the transfer of the charge by the first transfer unit and the fourth transfer unit, and the transfer of the charge by the second transfer unit and the third transfer unit There is provided an operation control means for performing the operation of transferring the electric charge to the fourth transfer unit at different timings while being prohibited.

By the way, in the optical sensor according to claim 1, as described in claim 2, each charge storage unit may be disposed so as to surround the periphery of each photodetection unit. In addition, as described in claim 3, each of the charge storage units is divided into a plurality of parts on the substrate, and each of the divided charge storage units may be connected by wiring.
Further, the optical sensor according to any one of claims 1 to 3 may include a pair of discharge elements that discharge the electric charge accumulated in each light detection unit as described in claim 4. Good.
According to such an optical sensor, since the discharge element is provided, it is possible to prevent unnecessary charges from being accumulated in the light detection unit when the discharge element is operated. Therefore, it is possible to improve detection accuracy when detecting the distance using the optical sensor.

Furthermore, in the optical sensor according to any one of claims 1 to 4, as described in claim 5 , a charge storage unit, a light detection unit, a reset element, a first transfer element, The second transfer element and the output element may be arranged on the substrate, and each transfer element may be divided into a plurality of parts on the substrate.

According to such an optical sensor, since each transfer element is divided into a plurality of parts, the operating speed of each transfer element can be improved.
Further, in the optical sensor according to claim 5 , each of the divided transfer elements may be arranged so as to surround each of the light detection units as described in claim 6 .

  According to such an optical sensor, since each divided transfer element is arranged around the optical detection unit, as a result, the optical detection unit can be arranged at a position close to the center of the optical sensor. Therefore, when a plurality of photosensors are arranged side by side, the interval between the photodetecting units can be made as constant as possible.

Furthermore, in the optical sensor according to claim 5 or 6 , as described in claim 7 , on the substrate, the first transfer element or the second transfer element connected to one of the light detection units and the one The length of the wiring connecting the other light detection unit and the length of the wiring connecting the first transfer element or the second transfer element connected to the other light detection unit and the other light detection unit are set equal. May be.

According to such an optical sensor, since the lengths of the wirings connecting the respective light detection units and the transfer elements are made equal, the charge transfer characteristics can be made constant.
Moreover, in the optical sensor according to any one of claims 1 to 7 , as described in claim 8 , each charge accumulating unit is arranged in line symmetry with each photodetecting unit interposed therebetween on the substrate. May be.

  According to such an optical sensor, since the distance from the light detection unit to each charge storage unit can be made equal, the characteristics when transferring charges from the light detection unit to each charge storage unit can be made constant. it can.

Furthermore, in the optical sensor according to any one of claims 1 to 8 , as described in claim 9 , on the substrate, each first transfer element and each second transfer element are each light detection unit. They may be arranged symmetrically with respect to each other.

According to such an optical sensor, the operating characteristics of each first transfer element and each second transfer element can be made constant.
Further, in the optical sensor according to any one of claims 1 to 9 , as described in claim 10 , on the substrate, each reset element and each output element are pointed with each photodetection unit interposed therebetween. You may arrange | position symmetrically.

According to such an optical sensor, the operation characteristics of each reset element and each output element can be made constant.
Next, in order to achieve the above object, as set forth in claim 11, a pair of charge accumulation units that accumulate charges, a pair of photodetection units that generate charges according to incident light, and each charge A pair of reset elements for resetting the charge accumulated in the accumulation unit to a predetermined constant charge, a first transfer unit for transferring charge from one photodetection unit to one charge accumulation unit, and the other photodetection Transfer unit including a second transfer unit that transfers charge from one unit to one charge storage unit, a third transfer unit that transfers charge from one photodetection unit to the other charge storage unit, and the other light A second transfer element including a fourth transfer unit that transfers charge from the detection unit to the other charge storage unit; a pair of output elements that output a current corresponding to the charge stored in each charge storage unit; and a reset element In the state where the charge of each charge storage unit is reset by An operation of transferring the charge to the first transfer unit while prohibiting the second transfer unit and the third transfer unit from transferring the charge, and a prohibition of the transfer of the charge by the first transfer unit and the fourth transfer unit The operation of transferring the charge to the third transfer unit is performed at different timings, and then the first transfer unit and the fourth transfer unit transfer the charge in a state where the charge of each charge storage unit is reset by the reset element. The operation of transferring the charge to the second transfer unit while inhibiting the transfer and the operation of transferring the charge to the fourth transfer unit while inhibiting the transfer of the charge by the second transfer unit and the third transfer unit are performed at different timings It is good also as an optical sensor provided with the operation control means to make .
Moreover, the optical sensor array of Claim 12 is provided with the optical sensor in any one of Claims 1-11 as a pair of optical sensor.

Therefore, according to such an optical sensor array, since the optical sensor according to any one of claims 1 to 11 is provided, the number of charge storage units can be reduced. Therefore, the integration rate of the photosensors constituting the photosensor array can be improved.

Furthermore, in the optical sensor array according to claim 12 , as described in claim 13 , each optical sensor may constitute a pair of optical sensors together with other optical sensors adjacent in the vertical direction. .

  According to such an optical sensor array, the optical sensors adjacent in the horizontal direction can simultaneously output detection results, so that each optical sensor constitutes a pair of optical sensors together with other optical sensors adjacent in the horizontal direction. Compared to the case, the movement of the object in the horizontal direction can be easily captured. Therefore, if this optical sensor array is mounted on a vehicle, it is possible to easily detect a pedestrian's jump-out or the like.

The distance detection device according to claim 14 configured to achieve the above object includes a light source, a light emission control means, a light sensor according to claim 1, and an element control means. A first reset unit that operates the pair of reset elements, and a first transfer element and a second transfer element corresponding to the other light detection unit in synchronization with the irradiation of the projection light by the light source after the first reset unit is operated. Without operating the first transfer element corresponding to one of the light detection units, and immediately after the operation of the first transfer element, the first transfer element and the second transfer element corresponding to the other light detection unit are operated. A first transfer unit that operates the second transfer element corresponding to one of the light detection units without operating, and a first output unit that operates each output element after the first transfer unit operates.

  Therefore, according to such a distance detection apparatus, since the optical sensor according to claim 1 is provided, the optical sensor can be reduced in size. In addition, since the element control means controls each transfer element, the charge by the light detection unit can be accumulated in the charge accumulation unit, so that the distance to the object to be measured can be detected well.

Incidentally, element controller Te distance detecting apparatus odor of claim 14, after actuation of the first output means, a second reset means for actuating the pair of reset element, after actuation of the first reset means, by the light source In synchronization with the irradiation of the projection light, the first transfer element corresponding to the other light detection unit is operated without operating the first transfer element and the second transfer element corresponding to one light detection unit, and this first Second transfer means for operating the second transfer element corresponding to the other photodetection unit without operating the first transfer element and the second transfer element corresponding to one photodetection unit immediately after the operation of the one transfer element And a second output means for activating each output element after the second transfer means is activated, and the distance to the object to be measured may be detected using all the optical sensors.

According to such a distance detection device, since the distance to the object to be measured is detected using all the optical sensors, the distance detection accuracy can be improved.
Furthermore, in the distance detection device according to claim 14, calculation means for calculating a distance to the object to be measured based on outputs from the pair of output elements is provided outside the distance detection device. However, as described in the fifteenth aspect , the distance detection device may include a calculation unit.

According to such a distance detection device, the distance to the object to be measured can be calculated by the distance detection device.
Further, in the distance detection device according to claim 14 or claim 15 , as described in claim 16 , the optical sensor includes a pair of discharge elements for discharging the charges accumulated in the respective light detection units. The control means may include discharge control means for operating each discharge element when the transfer means is not operated.

  According to such a distance detection device, it is possible to discharge the electric charge accumulated in the light detection unit that is unnecessary when the transfer means is not operated, so that the detection accuracy by the distance detection device can be improved.

Furthermore, in the distance detection device according to any one of claims 14 to 16 , the element control means, as described in claim 17 , sets the transfer means a predetermined number of times before the operation of the output means. You may make it implement repeatedly.

  According to such a distance detection device, the difference between the charges accumulated in the charge accumulation units can be increased by repeatedly operating the transfer means. For this reason, the output difference of the output by each output element can also be enlarged. Therefore, it is possible to easily detect the difference between the charges accumulated in the respective charge accumulation units, so that the detection accuracy can be improved.

  Therefore, since the distance detection device includes the optical sensor according to the first aspect, the optical sensor can be reduced in size. Further, by controlling each transfer element in the distance detection method, it is possible to accumulate charges by the light detection unit in the charge accumulation unit, so that the distance to the object to be measured can be detected well.

Embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a distance detection apparatus 1 according to the present invention.
[Embodiment]
The distance detection device 1 includes a clock oscillator 10, a light source 15, an optical sensor array 20, and a processing device 25.

  The clock oscillator 10 includes a known crystal oscillator, an FPGA (field programmable gate array), and the like, and the FAGA has a predetermined capacity with respect to the light source 15 and the optical sensor array 20 according to the number of counts by the crystal oscillator. Send a control signal. In FIG. 1, the clock oscillator 10 is illustrated to transmit a control signal to the optical sensor array 20 via the light source 15, but the clock oscillator 10 directly transmits to the optical sensor array 20. You may be comprised so that a control signal may be transmitted.

  The light source 15 includes a light emitting unit 16 that irradiates the object 5 to be measured with light such as infrared light. Further, the light source 15 irradiates light from the light emitting unit 16 intermittently according to a control signal from the clock oscillator 10.

  The optical sensor array 20 is disposed adjacent to the light emitting unit 16, receives reflected light (projected light) emitted from the light emitting unit 16 to the object 5 to be measured, and receives light from the light emitting unit 16. An output corresponding to the time difference from when the light is irradiated until the reflected light is received is sent to the processing device 25. Note that switching control of each element (transistor) constituting the optical sensor array 20 is performed by a control signal received from the clock oscillator 10. Details (configuration and operation) of the optical sensor array 20 will be described later.

  The processing device 25 is configured as a well-known microcomputer including a CPU, a ROM, a RAM, and the like, and calculates the distance to the object to be measured 5 according to the output from the optical sensor array 20.

  Next, the optical sensor array 20 will be described with reference to FIGS. FIG. 2 is a block diagram schematically showing the photosensor array 20, and FIG. 3 is a circuit diagram showing a pair of photosensors constituting the photosensor array 20.

  As shown in FIG. 2, the optical sensor array 20 includes optical sensors 40 and 60 arranged in a matrix on a substrate (silicon wafer). Here, the photosensors 40 and 60 are arranged by 2n in the vertical direction and m in the horizontal direction (n and m are natural numbers), and the photosensors 40 in the (2n-1) th row (odd line) are adjacent to each other. A pair of photosensors 80 are configured together with the photosensor 60 in the second n-th row (even line).

  Although the details will be described later, in this pair of photosensors 80, the odd-numbered photosensor 40 and the even-numbered photosensor 60 are set to share the charge accumulating unit A46 and the charge accumulating unit B66. Yes.

  As shown in FIGS. 2 and 3, each of the optical sensors 40 and 60 constituting the pair of optical sensors 80 includes photodetectors 41 and 61, reset elements 42 and 62, and transfer elements 43, 44, and 63, respectively. 64, discharge elements 45 and 65, charge storage units 46 and 66, amplification elements 47 and 67, and output elements 48 and 68.

  Here, as shown in FIG. 3, the photodetectors 41 and 61 are configured as photodiodes that generate and store charges (electrons in the present embodiment) corresponding to incident light (reflected light). The reset elements 42 and 62, transfer elements 43, 44, 63, and 64, discharge elements 45 and 65, amplification elements 47 and 67, and output elements 48 and 68 are configured as MOS transistors.

  The photodetector 41 (61) has an anode grounded (connected to GND) and a cathode connected to the transfer elements 43, 44 (63, 64) and the discharge element 45 (65).

  In the reset element 42 (62), one of the source and drain terminals is connected to the power supply (VDD), and the other terminal is the charge storage unit 46 (66), the transfer element 1A43 (transfer element 1B63), It is connected to the transfer element 2B64 (transfer element 1B44) and the amplifying element 47 (67) of another photosensor. When the reset element 42 (62) is turned on, the charge storage unit 46 (66) is reset (charged).

  The charge storage unit 46 (66) has one terminal grounded and the other terminal connected to the reset element 42 (62), the transfer elements 43 and 64 (63, 44), and the like.

  In the transfer element 1A43 (transfer element 1B63), one of the source and drain terminals is connected to the photodetector 41 (61) and the like, and the other terminal is connected to the charge storage unit 46 (66) and the like. ing. When the transfer element 1A43 (transfer element 1B63) is turned on, the charge accumulated in the photodetector 41 (61) moves to the charge accumulation unit 46 (66).

  The transfer element 2A44 (transfer element 2B64) has one of the source and drain terminals connected to the photodetector 41 (61) and the like, and the other terminal connected to the charge storage section 66 (46) and the like. ing. When the transfer element 2A44 (transfer element 2B64) is turned on, the charge accumulated in the photodetector 41 (61) moves to the charge accumulation unit 66 (46).

  The discharge element 45 (65) has one terminal of the source or drain connected to the power source and the other terminal connected to the photodetector 41 (61) or the like. When the discharge element 45 (65) is turned on, the charge accumulated in the photodetector 41 (61) is discharged. That is, the discharge element 45 (65) is used to prevent unnecessary charges from accumulating in the photodetector 41 (61).

  The amplifying element 47 (67) amplifies the output from the optical sensor 40 (60) in accordance with the potential of the charge storage unit 46 (66) in order to facilitate detection of the potential of the charge storage unit 46 (66). It is an element. One terminal of the amplifying element 47 (67) and the source or drain is connected to the power source, and the other terminal is connected to the output terminal 49 (of the optical sensor 40 (60) via the output element 48 (68). 69).

  The gate of the amplifying element 47 (67) is connected to an ungrounded terminal of the charge accumulating unit 46 (66), and the amplifying element 47 (67) is connected between the source and drain of the charge accumulating unit 46 (66). It is comprised so that the electric current according to the electric potential of may flow. However, when the output element 48 (68) is in the OFF state, no current flows between the source and drain of the amplifying element 47 (67).

  The gates of the reset elements 42 and 62, the transfer elements 43, 44, 63, and 64, the discharge elements 45 and 65, and the amplification elements 47 and 67 are connected to the clock oscillator 10 and transmitted from the clock oscillator 10. Each element is switching-controlled by the control signal.

Here, a specific layout when the pair of optical sensors 80 is arranged on the substrate will be described with reference to FIG.
As shown in FIG. 4, each of the optical sensors 40 and 60 constituting the pair of optical sensors 80 is configured by combining an N + diffusion region, a P + diffusion region, polysilicon, a metal wiring layer, a contact hole, and the like. ing. More specifically, the optical sensors 40 and 60 are arranged around the photodetectors 41 and 61, respectively.

  And the transfer elements 43 and 44 (63, 64) are arrange | positioned around the photodetector 41 (61). Here, each of the transfer elements 43 and 44 (63 and 64) is divided into four, and one terminal of the source or the drain is set so as to be in contact with the photodetector 41 (61). The other terminals of the transfer elements 43 and 44 (63 and 64) are connected by the metal wiring layer 50 (70), respectively.

  And the connection part (area | region displayed with the circle of the broken line in FIG. 4) with the metal wiring layer 50 (70) in the transfer elements 43 and 44 (63, 64) is comprised as a well-known floating diffusion, This floating diffusion corresponds to the above-described charge storage unit 66 (46).

  That is, the charge storage unit 46 (66) is divided into a region where the odd-numbered photosensors 40 are arranged and a region where the even-numbered photosensors 60 are arranged. Further, the patterns (arrangement of N + and P + diffusion regions, polysilicon, and metal wiring layers) constituting the charge storage units 46 and 66 and the transfer elements 43, 44, 63 and 64 include the charge storage unit 46 and the charge storage unit. 66, the metal wiring layer portions (broken line 90) located between 66 are arranged symmetrically about the axis of symmetry.

  Next, the reset element 42 (62), the discharge element 45 (65), the amplification element 47 (67), and the output element 48 (68) constitute the charge storage units 66 and 46 and the transfer elements 43, 44, 63, and 64. It is arranged outside the region where the pattern to be formed is formed. In other words, the reset element 42, the discharge element 45, the amplification element 47, and the output element 48 in the odd-numbered photosensor 40 are arranged in a region farther from the even-line photosensor 60, and the reset in the even-line photosensor 60 is performed. The element 62, the discharge element 65, the amplifying element 67, and the output element 68 are arranged in a region farther from the odd-numbered photosensors 40.

  Further, the reset element 42, the discharge element 45, the amplification element 47, and the output element 48 in the odd-numbered line optical sensor 40 and the reset element 62, the discharge element 65, the amplification element 67, and the output element 68 in the even-numbered line optical sensor 60 are shown. , A point on the basis of the center point O of the pair of optical sensors 80 (a point having an equal distance from each of the photodetectors 41 and 61 and an equal distance from each of the transfer elements 43 and 44 (63, 64)). A pattern is formed symmetrically.

  The photosensor array 20 (an assembly of a pair of photosensors 80) configured as described above operates according to a control signal from the clock oscillator 10. Here, the FAGA of the clock oscillator 10 transmits a control signal for driving the light source 15 and various elements according to the count number by the crystal oscillator.

  Specifically, the FAGA of the clock oscillator 10 transmits control signals in the order and control timing as shown in FIGS. FIG. 5 is a time chart showing the transmission order of control signals transmitted by the FAGA of the clock oscillator 10. FIG. 6 is a timing chart showing the control timing of the odd-numbered photosensors 40, and FIG. 7 is a timing chart showing the control timing of the even-numbered photosensors 60.

  As shown in FIG. 5A, the FAGA of the clock oscillator 10 first transmits a control signal for operating the odd-numbered optical sensor 40 (S110), and then controls the optical sensor 60 for the even-numbered line. A signal is transmitted (S120).

  In the operation of each of the optical sensors 40 and 60, the light source 15 and various elements are repeatedly operated at a predetermined cycle, and finally, an output corresponding to the charges accumulated in the charge accumulation units 46 and 66 is generated.

  In the operation of the odd-numbered line optical sensor 40, as shown in FIG. 5B, first, control signals for operating the reset element A42, the reset element B62, and the discharge element A45 are set for a predetermined time. Transmit (S210). Note that the predetermined time here may be a time that can reset the potentials of the charge storage units 46 and 66 (set to a preset potential). In addition, each element operates only while receiving a control signal (that is, each transistor is turned on only when receiving a control signal (a state where the source and drain are energized)).

  Subsequently, the FPGA of the clock oscillator 10 transmits a light emission control signal for causing the light source 15 to emit light to the light source 15 immediately after the reset element A42, the reset element B62, and the discharge element A45 are stopped, and the transfer element 1A43. A control signal for operating is transmitted (S220). Here, the light emission control signal for causing the light source 15 to emit light and the control signal for operating the transfer element 1A43 are set so that the transmission timings of the signals coincide (synchronize).

  Further, the transmission time of the control signal in this step (S220) is set to ¼ of the period when the light source 15 and the like are repeatedly operated. When the transfer element 1A43 operates in this way, the charge generated by the photodetector A41 moves to the charge storage unit A46.

  Next, immediately after the operation of the transfer element 1A43 is stopped, a control signal for operating the transfer element 2A44 is transmitted (S230). The transmission time of the control signal in this step (S230) is set to the same time as the transmission time of the control signal in S220 (a time that is 1/4 of the cycle when the light source 15 and the like are operated repeatedly). When the transfer element 2A44 operates in this way, the charge generated by the photodetector A41 moves to the charge storage unit B66.

  Subsequently, immediately after the operation of the transfer element 2A44 is stopped, a control signal for operating the discharge element A45 is transmitted (S240). Here, the transmission time of the control signal in this step (S240) is set to a time that is ½ of the cycle when the light source 15 or the like is operated repeatedly. In this way, charges are not accumulated in the photodetector A41 while the discharge element A45 is operating.

  Next, steps S220 to S240 are repeated a predetermined number of times in the FPGA. Then, control signals for operating the output element A48 and the output element B68 are sequentially transmitted (S260, S270). According to these steps (S260, S270), the charges accumulated in the charge accumulation units 46, 66 (charge accumulation units 46, 66) are output from the output units 49, 69 (see FIG. 3) of the photosensors 40, 60, respectively. Current value corresponding to the potential 66) is output to the processing device 25. In this way, the odd line photosensors 40 are activated.

  Next, the operation (S120) of the photosensor 60 for even lines will be described. The even line photosensor 60 is operated as shown in FIG. However, since this process is mostly the same as the operation of the photosensor 40 of the odd-numbered lines shown in FIG. 5B, only different parts will be described.

  In the operation of the even-numbered photosensor 60, the FPGA of the clock oscillator 10 first transmits a control signal for operating the discharge element B65 instead of the control signal for operating the discharge element A45 in S210 (S310). Subsequently, a control signal for operating the transfer element 2A63 is transmitted instead of the control signal for operating the transfer element 1A43 in S220 (S320).

  Next, instead of the control signal for operating the transfer element 2A44 in S230, a control signal for operating the transfer element 2B64 is transmitted (S330). Subsequently, a control signal for operating the discharge element B65 is transmitted instead of the control signal for operating the discharge element A45 in S240 (S340).

  Next, steps S320 to S340 are repeated a predetermined number of times in the FPGA. Then, similarly to S260 and S270, control signals for operating the output element A48 and the output element B68 are sequentially transmitted (S360 and S370). In this way, the photosensor array 20 operates.

  Here, in the distance detection device 1, light (projection light) emitted from the light source 15 is reflected by the object to be measured 5 and received by the photodetectors 41 and 61 of the photosensor array 20. Therefore, the reflected light received by each of the photodetectors 41 and 61 is detected with a delay of a predetermined time Φ from the projection light, as shown in FIGS.

  Then, since the transfer element 1A43 (transfer element 1B63) operates in synchronization with the projection light, the charge corresponding to the reflected light received when the light source 15 emits the projection light moves to the charge storage unit A46. To do.

  In other words, the longer the distance from the light source 15 to the photosensor array 20 via the object to be measured 5, the smaller the amount of charge that moves to the charge storage unit A 46. In the present embodiment, the potential of the charge storage unit A46 decreases according to the length of time that the reflected light is received when the light source 15 emits projection light.

  Further, since the transfer element 2A44 (transfer element 2B64) operates immediately after the operation of the transfer element 1A43 (transfer element 1B63), the charge storage unit B66 received light after a delay after the light source 15 stopped emitting projection light. The charge corresponding to the reflected light moves.

  In other words, the longer the distance from the light source 15 to the photosensor array 20 via the object to be measured 5 is, the more charges move to the charge storage unit B66. In the present embodiment, the potential of the charge storage unit B66 decreases according to the length of time that the reflected light is received after the light source 15 stops emitting projection light.

  Therefore, if the potential of the charge storage unit A46 is compared with the potential of the charge storage unit B66, the distance from the distance detection device 1 to the object to be measured 5 (more precisely, the object 5 to be measured from the light source 15). And the sum of the distance from the object to be measured 5 to the optical sensor array 20). Here, with respect to mathematical formulas used for actual distance detection, detailed mathematical formulas are disclosed in, for example, the above-mentioned Patent Document 1 (Special Table 2006-516324), and in this embodiment, for example, such mathematical formulas are used. Thus, the actual distance can be detected.

  In the above embodiment, the pair of optical sensors 80 corresponds to the optical sensor referred to in the present invention, and the amplification elements 47 and 67 and the output elements 48 and 68 correspond to the output elements referred to in the present invention. The clock oscillator 10 corresponds to the light emission control means and the element control means referred to in the present invention, and the calculation means corresponds to the processing device 25 referred to in the present invention.

  Further, the step of S210 in the time chart showing the transmission order of the control signals transmitted by the FAGA of the clock oscillator 10 corresponds to the first reset means / step in the present invention, and the steps of S220 and S230 are the first in the present invention. This corresponds to one transfer means / process. In addition, S260 and S270 correspond to the first output means / step in the present invention, and S310 corresponds to the second reset means in the present invention.

  In addition, the steps S320 and S330 correspond to the second transfer means in the present invention, the processes in S360 and S370 correspond to the second output means in the present invention, and the processes in S240 and S340 correspond to the discharge in the present invention. It corresponds to the control means.

[Effects of the embodiment]
In the distance detection device 1 described in detail above, each of the optical sensors 40 and 60 configuring the optical sensor array 20 transfers a pair of charges from the pair of photodetectors 41 and 61 to one charge storage unit A46. Transfer elements 43 and 63 and a pair of transfer elements 44 and 64 that transfer charges from the pair of photodetectors 41 and 61 to the other charge storage unit B66 are provided.

  Further, the clock oscillator 10 first operates the pair of reset elements 42 and 62, and corresponds to one photodetector A 41 in synchronization with the irradiation of the projection light from the light source 15 after the reset elements 42 and 62 are operated. The transfer element 43 is activated. Then, immediately after the operation of the transfer element 43, the transfer element 44 corresponding to one of the photodetectors A41 is operated, and after the operation of the transfer element 44, the output elements 48 and 68 are operated.

  Furthermore, the clock oscillator 10 operates the pair of reset elements 42 and 62 again after operating the output elements 48 and 68, and synchronizes with the irradiation of the projection light from the light source 15 after the reset elements 42 and 62 operate. The transfer element 63 corresponding to the other photodetector B61 is operated. Then, immediately after the operation of the transfer element 63, the transfer element 64 corresponding to the other photodetector B61 is operated, and after the transfer element 64 is operated, the output elements 48 and 68 are operated.

  That is, according to such a distance detection device 1, the clock oscillator 10 controls the transfer elements 43 and 43 so that the charge accumulation units 46 and 66 are charged by the photodetector A 41 according to the light reception timing of the reflected light. Therefore, the distance to the object to be measured can be detected well.

Moreover, according to such a distance detection apparatus 1, since the distance to a to-be-measured object is detected using all the optical sensors 40 and 60, distance detection accuracy can be improved.
In addition, according to such a distance detection device 1, as compared with a photosensor having two charge storage units for one photodetector, like the photosensors 40 and 60 of the conventional configuration, Since the sensors 40 and 60 can be reduced in size, the integration rate of the optical sensors 40 and 60 can be improved.

  In the optical sensors 40 and 60, the charge storage units 46 and 66, the photodetectors 41 and 61, the reset elements 42 and 62, the transfer elements 43, 44, 63, and 64 that constitute the optical sensors 40 and 60, and the output element. 48 and 68 are arranged on the substrate, and the transfer elements 43, 44, 63 and 64 and the charge storage units 46 and 66 are divided into a plurality of parts on the substrate.

  Therefore, according to such optical sensors 40 and 60, since each transfer element 43, 44, 63, and 64 is divided | segmented into plurality, the operating speed of each transfer element can be improved. In addition, since the charge storage units 46 and 66 are also divided into a plurality of parts, the charge storage units 46 and 66 can store a large amount of charge for the area of the charge storage units 46 and 66 on the substrate. Therefore, charge accumulation characteristics can be improved.

In the optical sensors 40 and 60, the transfer elements 43, 44, 63, and 64 divided into a plurality are disposed so as to surround the respective photodetectors 41 and 61.
Therefore, according to such photosensors 40, 60, the transfer elements 43, 44, 63, 64 divided around the photodetectors 41, 61 are arranged. The photodetectors 41 and 61 can be arranged at positions close to the center. Therefore, when a plurality of optical sensors 40, 60 are arranged side by side, the interval between the photodetectors 41, 61 can be made as constant as possible.

  Furthermore, in the optical sensors 40 and 60, the length of the metal wiring layer 50 that connects the transfer element 43 connected to one photodetector A41 or the transfer element 44 and one photodetector A41 on the substrate, The lengths of the transfer element 63 or transfer element 64 connected to the other photodetector B61 and the metal wiring layer 70 connecting the other photodetector B61 are set equal.

  Therefore, according to such optical sensors 40 and 60, the lengths of the metal wiring layers 50 and 70 connecting the photodetectors 41 and 61 and the transfer elements 43, 44, 63, and 64 are made equal. The charge transfer characteristic can be made constant.

  In the optical sensors 40 and 60, the charge storage units 46 and 66 are arranged on the substrate in line symmetry with the photodetectors 41 and 61 in between, and the transfer elements 43 and 63 and the respective sensors. The transfer elements 44 and 64 are arranged symmetrically with respect to the photodetectors 41 and 61.

  Therefore, according to such photosensors 40 and 60, the distance from the photodetectors 41 and 61 to the charge storage units 46 and 66, and from the photodetectors 41 and 61 to the transfer elements 43, 44, 63, and 64, respectively. Can be made equal to each other, so that characteristics at the time of transferring charges from the photodetectors 41 and 61 to the charge storage units 46 and 66 and the transfer elements 43, 44, 63, and 64 can be made constant. .

  In the optical sensors 40 and 60, the reset elements 42 and 62 and the output elements 48 and 68 may be arranged point-symmetrically on the substrate with the photodetectors 41 and 61 interposed therebetween.

  Therefore, according to the photosensors 40 and 60, the distances from the photodetectors 41 and 61 to the reset elements 42 and 62 and the output elements 48 and 68 can be made equal. 62 and the output elements 48 and 68 can be made constant in operating characteristics.

Furthermore, each optical sensor 40 (60) constituting the optical sensor array 20 constitutes a pair of optical sensors 80 together with another optical sensor 60 (40) adjacent in the vertical direction.
Therefore, according to such an optical sensor array 20, since the optical sensor 40 (60) adjacent in the horizontal direction can output the detection result at the same time, each optical sensor 40 (60) is adjacent to the horizontal direction. Compared to the case where the pair of optical sensors 80 is configured together with the optical sensor 40 (60), it is possible to make it easier to capture the movement of the object in the horizontal direction. Therefore, if this optical sensor array 20 is mounted on a vehicle, it is possible to easily detect a pedestrian's jump-out or the like.

Further, the processing device 25 calculates the distance to the object to be measured based on the outputs from the pair of output elements 48 and 68.
Therefore, according to such a distance detection device, the distance to the object to be measured can be calculated by the distance detection device.

  The optical sensors 40 and 60 include a pair of discharge elements 45 and 65 for discharging charges accumulated in the photodetectors 41 and 61. The clock oscillator 10 operates the transfer elements 43, 44, 63, and 64. When not, the discharge elements 45 and 65 are operated.

  Therefore, according to such a distance detection device 1, it is possible to discharge the electric charges accumulated in the photodetectors 41 and 61 that are not required when the transfer means is not operated, so that the detection accuracy of the distance detection device 1 can be improved. Can be improved.

Further, in the distance detection device 1, the clock oscillator 10 repeatedly operates the transfer elements 43, 44, 63, and 64 a predetermined number of times before the output elements 48 and 68 are operated.
Therefore, according to the distance detection device 1 as described above, the difference between charges accumulated in the charge accumulation units 46 and 66 can be increased by repeatedly operating the transfer elements 43, 44, 63 and 64. For this reason, the output difference of the output by each output element 48 and 68 can also be enlarged. Therefore, it is possible to easily detect the difference between the charges accumulated in the charge accumulation units 46 and 66, and the detection accuracy can be improved.

[Other Embodiments]
Embodiments of the present invention are not limited to the above-described embodiments, and can take various forms as long as they belong to the technical scope of the present invention.

  For example, photodiodes are employed as the photodetectors 41 and 61. However, for example, a phototransistor or the like can be used as an alternative if it is an element having a function of generating charges according to incident light.

  In the above embodiment, both the optical sensors 40 and 60 constituting the pair of optical sensors 80 are operated to detect the distance to the non-distance measuring object. You may make it detect the distance to a to-be-measured object using only one optical sensor 40,60. That is, only one of the operation of the odd-numbered line photosensor 40 shown in FIG. 5B and the operation of the even-numbered photosensor 60 shown in FIG. 6C may be performed.

  In the above embodiment, the clock oscillator 10 (FPGA) is configured to generate control signals for driving the light source 15 and the optical sensor array 20, but for example, the clock oscillator 10 includes only an oscillator such as a crystal oscillator. The signal from the clock oscillator 10 is input to the processing device 25 (see the broken line in FIG. 1), and the processing device 25 supplies the light source 15 and the optical sensor array 20 according to the count number by the clock oscillator 10. On the other hand, a predetermined control signal may be transmitted.

  Specifically, the time chart shown in FIG. 5 may be a flowchart showing processing executed by the CPU of the processing device 25. In this case, in FIG. 5 (b) and FIG. 5 (c), after the processes of S240 and S340, a process for determining whether or not the number of executions of S220 to S240 has reached a predetermined number of times set in advance ( S250, S350) may be newly provided, and the processes from S220 onward may be repeated until the number of times of execution of these processes reaches a predetermined number set in advance. Even if it does in this way, the effect similar to the said embodiment is acquired.

It is a block diagram which shows schematic structure of a distance detection apparatus. It is a block diagram which shows an optical sensor array typically. It is a circuit diagram which shows a pair of optical sensor which comprises an optical sensor array. It is explanatory drawing which shows the specific layout at the time of arrange | positioning a pair of optical sensor on a board | substrate. It is a time chart which shows the transmission order of the control signal which FAGA of a clock oscillator transmits. It is a timing chart which shows the control timing of the optical sensor of an odd line. It is a timing chart which shows the control timing of the photosensor of an even line.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Distance detection apparatus, 5 ... Object to be measured, 10 ... Clock oscillator, 15 ... Light source, 16 ... Light emission part, 20 ... Optical sensor array, 25 ... Processing apparatus, 40, 60 ... Optical sensor, 41 ... Light Detector A, 42 ... Reset element A, 43 ... Transfer element 1A, 44 ... Transfer element 2A, 45 ... Discharge element A, 46 ... Charge storage unit A, 47 ... Amplification element A, 48 ... Output element A, 50, 70 ... metal wiring layer, 61 ... photodetector B, 62 ... reset element B, 63 ... transfer element 1B, 64 ... transfer element 2B, 65 ... discharge element B, 66 ... charge storage part B, 67 ... amplification element B, 68 ... Output element B, 80 ... A pair of optical sensors.

Claims (17)

A pair of charge storage sections that store charge;
A pair of photodetectors that generate charges in response to incident light;
A pair of reset elements for resetting the charge accumulated in each of the charge accumulation units to a predetermined constant charge;
First transfer unit for transferring the charge to one of the charge storage portion from one of the light detecting unit, and the other of the second transfer unit for transferring charges to the charge storage portion of the one from the optical detection unit, a first transfer device comprising When,
A second transfer unit that includes a third transfer unit that transfers charges from the one photodetection unit to the other charge storage unit; and a fourth transfer unit that transfers charges from the other photodetection unit to the other charge storage unit. A transfer element;
A pair of output elements for outputting a current corresponding to the charge accumulated in each of the charge accumulation units after the charge is transferred by the first transfer element and the second transfer element ;
An operation of transferring charges to the first transfer unit while prohibiting the second transfer unit and the third transfer unit from transferring charges in a state where the charges of the charge storage units are reset by the reset element. And the operation of transferring the charge to the third transfer unit at different timings while prohibiting the first transfer unit and the fourth transfer unit from transferring the charge. An operation of transferring the charge to the second transfer unit while prohibiting the first transfer unit and the fourth transfer unit from transferring the charge in a state where the charge of the storage unit is reset, and the second transfer unit And an operation control means for performing the operation of transferring the charge to the fourth transfer unit at different timings while prohibiting the third transfer unit from transferring the charge ,
With
The charge storage unit, the light detection unit, the reset element, the first transfer element, the second transfer element, and the output element that constitute the photosensor are arranged on the substrate,
On the substrate, each of the charge storage units is arranged symmetrically with respect to each of the photodetecting units. The optical sensor according to claim 1, wherein each of the charge storage units is arranged so as to surround the periphery of each of the light detection units. The optical sensor according to claim 2, wherein each of the charge storage units is divided into a plurality of parts on the substrate, and each of the divided charge storage units is connected by wiring. The optical sensor according to any one of claims 1 to 3, further comprising a pair of discharge elements that discharge the electric charges accumulated in the respective light detection units. 5. The optical sensor according to claim 1, wherein each of the transfer elements is divided into a plurality of parts on the substrate. The optical sensor according to claim 5, wherein each of the transfer elements divided into a plurality is arranged so as to surround each of the light detection units. On the substrate, the length of the wiring connecting the first transfer element or the second transfer element connected to one photodetection unit and the one photodetection unit, and the first transfer element connected to the other photodetection unit The length of the wiring which connects 1 transfer element or 2nd transfer element, and this other photon detection part is set equally. The optical sensor of Claim 5 or Claim 6 characterized by the above-mentioned. 8. The optical sensor according to claim 1, wherein the charge storage units are arranged symmetrically with respect to the light detection unit on the substrate. The said 1st transfer element and each said 2nd transfer element are arrange | positioned line-symmetrically on both sides of each said photon detection part on the said board | substrate. The optical sensor described in 1. The light according to any one of claims 1 to 9, wherein the reset elements and the output elements are arranged point-symmetrically on the substrate with the light detection units interposed therebetween. Sensor. A pair of charge storage sections that store charge;
A pair of photodetectors that generate charges in response to incident light;
A pair of reset elements for resetting the charge accumulated in each of the charge accumulation units to a predetermined constant charge;
First transfer unit for transferring the charge to one of the charge storage portion from one of the light detecting unit, and the other of the second transfer unit for transferring charges to the charge storage portion of the one from the optical detection unit, a first transfer device comprising When,
A second transfer unit that includes a third transfer unit that transfers charges from the one photodetection unit to the other charge storage unit; and a fourth transfer unit that transfers charges from the other photodetection unit to the other charge storage unit. A transfer element;
A pair of output elements for outputting a current corresponding to the charge accumulated in each of the charge accumulation units after the charge is transferred by the first transfer element and the second transfer element ;
An operation of transferring charges to the first transfer unit while prohibiting the second transfer unit and the third transfer unit from transferring charges in a state where the charges of the charge storage units are reset by the reset element. And the operation of transferring the charge to the third transfer unit at different timings while prohibiting the first transfer unit and the fourth transfer unit from transferring the charge. An operation of transferring the charge to the second transfer unit while prohibiting the first transfer unit and the fourth transfer unit from transferring the charge in a state where the charge of the storage unit is reset, and the second transfer unit And an operation control means for performing the operation of transferring the charge to the fourth transfer unit at different timings while prohibiting the third transfer unit from transferring the charge ,
An optical sensor comprising: An optical sensor array in which optical sensors are arranged in a matrix in horizontal and vertical directions,
Each photosensor constituting the photosensor array constitutes a pair of photosensors together with other photosensors adjacent to each photosensor array,
An optical sensor array comprising the optical sensor according to claim 1 as each of the pair of optical sensors. The photosensor array according to claim 12, wherein each photosensor constituting the photosensor array constitutes a pair of photosensors together with another photosensor adjacent in the vertical direction. A light source that emits projection light to an object to be measured;
Light emission control means for irradiating the light source with projection light for a predetermined time set in advance;
An optical sensor that performs output according to the time until the projected light is received by receiving the reflected light reflected by the object to be measured;
Element control means for controlling the operation of each element constituting the optical sensor;
A distance detection device comprising:
The optical sensor is
A pair of charge storage sections that store charge;
A pair of photodetectors for generating electric charges according to the reflected light;
A pair of reset elements for resetting the charge accumulated in each of the charge accumulation units to a predetermined constant charge;
A pair of first transfer elements that transfer charges from each of the light detection units to one of the charge storage units;
A pair of second transfer elements that transfer charges from each of the light detection units to the other charge storage unit;
A pair of output elements that output a current corresponding to the charge accumulated in each of the charge accumulation units;
With
The element control means is at least
First reset means for activating the pair of reset elements;
After the operation of the first reset means, in synchronization with the irradiation of the projection light by the light source, the first transfer element and the second transfer element corresponding to the other light detection unit are not operated, The corresponding first transfer element is actuated, and immediately after the first transfer element is actuated, the one photodetecting section is operated without actuating the first transfer element and the second transfer element corresponding to the other photodetecting section. First transfer means for actuating a second transfer element corresponding to
First output means for actuating each output element after actuation of the first transfer means;
Second reset means for operating the pair of reset elements after the first output means is activated;
After the operation of the first reset means, the other light detection unit is operated without operating the first transfer element and the second transfer element corresponding to the one light detection unit in synchronization with the irradiation of the projection light from the light source. The first transfer element corresponding to the first photo detector is actuated, and immediately after the first transfer element is actuated, the first photo detector and the second transfer device corresponding to the one photo detector are not operated, and the other photo detector is detected. Second transfer means for actuating a second transfer element corresponding to the section;
Second output means for actuating each output element after actuation of the second transfer means;
A distance detection device comprising: The distance detecting apparatus according to claim 1 4, characterized in that it comprises a calculating means for calculating a distance to the object distance measuring object on the basis of output from the pair of output elements. The photosensor includes a pair of discharge elements that discharge the electric charge accumulated in each of the light detection units,
The element control means includes
16. The distance detecting device according to claim 14, further comprising discharge control means for operating each of the discharge elements when the transfer means is not operated. The element control means includes
The distance detecting device according to any one of claims 14 to 16 , wherein the transfer unit is repeatedly performed a predetermined number of times before the output unit is operated.