JP3908973B2 - Position detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a position detection device that detects a light incident position using a photodetector that outputs a current signal from any one of a plurality of output terminals according to a light incident position on a light receiving surface. Is.
[0002]
[Prior art]
As a position detection device that detects a light incident position on a light receiving surface, a device that detects a radiation incident position using a scintillator is known. As a position detection device for detecting the incident position of this radiation, a configuration in which a plurality of photodetectors are combined with a large number of scintillators or a single scintillator having a large area (prior art 1), and a large number of arrays. A scintillator is combined with a single position detection type photodetector to perform discrimination for each scintillator (prior art 2).
[0003]
In such a position detection device, the incident position is detected as follows. Radiation such as gamma rays and beta rays incident on the scintillator is converted into light, and this light enters a nearby photodetector. Here, the output value of the detection signal of the photodetector located far from the radiation incident position is very small as compared with the output value of the detection signal of the photodetector near the position where the radiation is incident. Then, these outputs of the photodetector are calculated by the position calculation circuit in the next stage, and the incident position of the radiation can be known. A scintillation camera is a typical example of this. A photon emitted by a scintillation phenomenon generated by gamma rays in a thin flat scintillator is dispersed by a scintillator and a medium that diffuses light, and is coupled to many of them. The two-dimensional position information where the gamma rays are incident is obtained from these outputs after reaching the photodetector. In such a photodetector, the light generated in the scintillator diffuses and spreads, so that the position resolution is deteriorated, and particularly, in the peripheral portion of the photodetector. This problem is solved as follows.
[0004]
The position detection device of the prior art 1 obtains an energy signal by adding the output signals of the respective photodetectors, and gives a signal generated from the energy signal as a threshold value to the threshold amplifier. The threshold amplifier amplifies a component larger than the threshold from the output signal of each photodetector and performs an operation. Thus, a method has been devised to prevent resolution degradation due to the spread of light by calculating using only signals in the vicinity of the scintillator emitted by the incidence of radiation (for example, US Pat. No. 3732419, US Pat. No. .4475042).
[0005]
The position detection device of Prior Art 2 uses a resistor between each output terminal of the photodetector in order to reduce the number of current signals output from the photodetector and reduce the scale of the subsequent signal processing circuit. A resistor chain circuit to be connected is provided, and the radiation incident position is detected by calculating the center of gravity of the signals output from both end points of the resistor chain circuit. In this position detection device, an amplifier is provided between the output terminal corresponding to the vicinity of the light receiving surface of the photodetector and the resistor chain circuit, thereby outputting from the output terminal corresponding to the vicinity of the light receiving surface of the photodetector. The amplified signal is amplified to improve both position resolution and energy signal uniformity.
[0006]
Japanese Patent Publication No. 5-45919 discloses that the current signals output from the output terminals corresponding to the vicinity of the light receiving surface of the photodetector and the vicinity of the center of the light detector are independently extracted and processed. A position detection device (prior art 3) that switches and outputs a result is disclosed.
[0007]
[Problems to be solved by the invention]
However, each of the above prior arts has the following problems. That is, in the position detection device according to the prior art 1, in order to ensure a sufficient position resolution, a large number of small photodetectors must be arranged, and a circuit for processing a current signal output from the photodetectors is required. The scale must be large. Therefore, this position detection device has a complicated and large-scale configuration and is expensive. Although the position detection device according to the prior art 2 has a simple circuit configuration, the degree of improvement in position resolution near the periphery of the light receiving surface of the photodetector is not sufficient, and the uniformity of the energy signal is somewhat. Although improved, it is not enough. The position detection device according to the prior art 3 improves the position resolution near the periphery of the light receiving surface.
[0008]
However, the position detecting device according to the prior art 3 takes out the current signals output from the output terminals corresponding to the vicinity of the light receiving surface of the light detector and the vicinity of the center of the light detector independently of each other and processes the signals. When the current signal output from the sensor changes, an error in position classification occurs near the periphery of the light receiving surface, and the position resolution near the periphery of the light receiving surface may deteriorate. In addition, this degraded position resolution can be improved by correcting the position correction table, but it is necessary to prepare separate position correction tables near the periphery and near the center. The work is complicated. Furthermore, since the current signal output from the output terminal corresponding to the vicinity of the periphery of the light receiving surface of the photodetector is independently extracted and processed, unless the light is dispersed using the optical system and incident on the light receiving surface, The position resolution near the periphery of the light receiving surface cannot be improved.
[0009]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a position detection apparatus having a simple configuration and excellent in both position resolution and energy signal uniformity.
[0010]
[Means for Solving the Problems]
The position detection device according to the first invention is: (1) M output terminals P according to a one-dimensional position on the light receiving surface that receives light. ₁ ~ P _M (Where M is an integer of 4 or more), and M output terminals P according to the light incident position on the light receiving surface. ₁ ~ P _M A photodetector that outputs a current signal from any one of the output terminals, and (2) M output terminals P ₁ ~ P _M Output terminal P _m And output terminal P _{m + 1} Resistor R provided between _m (Where m is an integer of 2 or more and (M-2) or less), (3) M output terminals P having a first input terminal, a second input terminal and an output terminal. ₁ ~ P _M Output terminal P ₁ The first input terminal is connected to the output terminal P ₂ A first input unit that outputs a voltage value from the output terminal based on the value of the current signal input to each of the first input terminal and the second input terminal; and (4) M output terminals P having a first input terminal, a second input terminal and an output terminal ₁ ~ P _M Output terminal P _M The first input terminal is connected to the output terminal P _M-1 A second input terminal connected to the second input unit, and a second arithmetic unit for outputting a voltage value from the output terminal based on the value of the current signal input to each of the first input terminal and the second input terminal; (5) A position calculation unit that obtains a light incident position on the light receiving surface based on voltage values output from the output terminals of the first calculation unit and the second calculation unit, respectively.
[0011]
The position detection device according to the first invention detects a one-dimensional position where light is incident on the light receiving surface of the photodetector. M output terminals P according to the one-dimensional position on the light receiving surface of the photodetector. ₁ ~ P _M And M output terminals P according to the light incident position on the light receiving surface. ₁ ~ P _M A current signal is output from any one of the output terminals. In addition, M output terminals P ₁ ~ P _M Output terminal P _m And output terminal P _{m + 1} Resistor R between _m Is provided. However, M is an integer greater than or equal to 4, and m is each integer greater than or equal to 2 and less than (M-2). That is, (M−2) output terminals P ₂ ~ P _M-1 Is (M-3) resistors R ₂ ~ R _M-2 Connected to a resistor chain circuit. Output terminal P at one end ₁ Is connected to the first input terminal of the first arithmetic unit and the output terminal P next to it is ₂ Is connected to the second input terminal of the first arithmetic unit, and the voltage value is output from the output terminal of the first arithmetic unit based on the value of the current signal input to each of the first input terminal and the second input terminal. Is done. The output terminal P at the other end _M Is connected to the first input terminal of the second arithmetic unit and the output terminal P next to it _M-1 Is connected to the second input terminal of the second arithmetic unit, and the voltage value is output from the output terminal of the second arithmetic unit based on the value of the current signal input to each of the first input terminal and the second input terminal. Is done. Then, the position calculation unit determines the light incident position on the light receiving surface based on the voltage values output from the output terminals of the first calculation unit and the second calculation unit. Thus, in this position detection device, the current signals output from the output terminals corresponding to the vicinity of the periphery and the center of the light receiving surface of the photodetector are not independently extracted and processed, Both are collected and processed.
[0012]
The position detection device according to the second invention is: (1) M × N output terminals P according to the two-dimensional position on the light receiving surface that receives light. _1,1 ~ P _{M, N} Are arranged (where M and N are integers of 4 or more), and M × N output terminals P according to the light incident position on the light receiving surface. _1,1 ~ P _{M, N} A photodetector that outputs a current signal from any one of the output terminals, and (2) M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{m, n} And output terminal P _{m, n + 1} Resistor R provided between _{m, n} (Where m is an integer from 1 to M, n is an integer from 2 to (N-2)), and (3) M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{m, 2} And output terminal P _{m + 1,2} Resistor R provided between _{m, a} (Where m is an integer from 2 to (M-2)), (4) M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{m, N-1} And output terminal P _{m + 1, N-1} Resistor R provided between _{m, b} (Where m is an integer of 2 or more and (M-2) or less), (5) M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{m, 1} And output terminal P _{m + 1,1} Resistor R provided between _{m, c} (Where m is an integer from 2 to (M-2)), (6) M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{m, N} And output terminal P _{m + 1, N} Resistor R provided between _{m, d} (Where m is an integer not less than 2 and not more than (M-2)), (7) has a first input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal; × N output terminals P _1,1 ~ P _{M, N} Output terminal P _1,1 The first input terminal is connected to the output terminal P _1,2 The second input terminal is connected to the output terminal P _2,1 The third input terminal is connected to the output terminal P _2,2 A first input unit that outputs a voltage value from the output terminal based on the value of the current signal input to each of the first to fourth input terminals, and (8) the first It has an input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal, and M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{1, N} The first input terminal is connected to the output terminal P _{1, N-1} The second input terminal is connected to the output terminal P _{2, N} The third input terminal is connected to the output terminal P _{2, N-1} A second input unit that outputs a voltage value from the output terminal based on the value of the current signal input to each of the first to fourth input terminals, and (9) the first It has an input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal, and M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{M, 1} The first input terminal is connected to the output terminal P _{M, 2} The second input terminal is connected to the output terminal P _M-1,1 The third input terminal is connected to the output terminal P _M-1,2 A third input unit that outputs a voltage value from the output terminal based on the value of the current signal input to each of the first to fourth input terminals, and (10) the first It has an input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal, and M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _{M, N} The first input terminal is connected to the output terminal P _{M, N-1} The second input terminal is connected to the output terminal P _{M-1, N} The third input terminal is connected to the output terminal P _{M-1, N-1} A fourth input terminal, and a fourth arithmetic unit that outputs a voltage value from the output terminal based on the value of the current signal input to each of the first to fourth input terminals, and (11) the first A position calculation unit for obtaining a light incident position on the light receiving surface based on voltage values output from output terminals of the calculation unit, the second calculation unit, the third calculation unit, and the fourth calculation unit, respectively. And
[0013]
The position detection device according to the second invention detects a two-dimensional position where light is incident on the light receiving surface of the photodetector. Even in this position detection device, the current signals output from the output terminals corresponding to the vicinity of the periphery and the center of the light receiving surface of the photodetector are not extracted and processed independently of each other, but are combined. Processed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.
[0015]
(First embodiment)
First, a first embodiment of a position detection device according to the present invention will be described. FIG. 1 is a configuration diagram of a position detection device 1 according to the first embodiment. The position detection device 1 shown in this figure detects a one-dimensional position where light is incident on the light receiving surface of the photodetector 110. In addition to the photodetector 110, the position detection device 1 includes a resistance chain circuit 120, a first calculation. Unit 130, second calculation unit 140, and position calculation unit 170.
[0016]
The photodetector 110 has M output terminals P corresponding to a one-dimensional position on the light receiving surface that receives light (including radiation). ₁ ~ P _M Are provided in order. However, M is an integer of 4 or more. M output terminals P ₁ ~ P _M Output terminal P ₁ Corresponds to one end of the light receiving surface, and the output terminal P _M Corresponds to the other end of the light receiving surface. The photodetector 110 includes M output terminals P in accordance with the light incident position on the light receiving surface. ₁ ~ P _M A current signal is output from one or more of the output terminals.
[0017]
The resistor chain circuit 120 includes (M-3) resistors R ₂ ~ R _M-2 including. These (M-3) resistors R ₂ ~ R _M-2 Are cascaded, of which resistor R _m Is the output terminal P of the photodetector 110 _m And output terminal P _{m + 1} Between. However, m is each integer below 2 (M-2).
[0018]
The first arithmetic unit 130 includes an amplifier 131, an amplifier 132, and an adder 135. The input terminal of the amplifier 131 is the output terminal P of the photodetector 110. ₁ And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 132 is the output terminal P of the photodetector 110. ₂ And a voltage value corresponding to the current value input to the input terminal is output. The adder 135 receives the voltage values output from the amplifier 131 and the amplifier 132, adds the voltage values, and outputs a voltage value X1 representing the addition result from the output terminal.
[0019]
The second arithmetic unit 140 includes an amplifier 141, an amplifier 142, and an adder 145. The input terminal of the amplifier 141 is the output terminal P of the photodetector 110. _M And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 142 is the output terminal P of the photodetector 110. _M-1 And a voltage value corresponding to the current value input to the input terminal is output. The adder 145 receives the voltage values output from the amplifier 141 and the amplifier 142, adds the voltage values, and outputs a voltage value X2 representing the addition result from the output terminal.
[0020]
The position calculation unit 170 calculates the light incident position on the light receiving surface of the photodetector 110 based on the voltage value X1 output from the first calculation unit 130 and the voltage value X2 output from the second calculation unit 140. It is what you want. The position calculation unit 170 includes an adder 171, an A / D converter 172a, an A / D converter 172b, a position calculator 173, a wave height discriminator 174, and a control signal generator 175.
[0021]
The adder 171 receives the voltage value X1 output from the first calculation unit 130 and the voltage value X2 output from the second calculation unit 140, and corresponds to the sum of the voltage value X1 and the voltage value X2. Outputs the voltage value. One A / D converter 172 a receives the voltage value (analog value) output from the adder 171, converts it to a digital value, and outputs this digital value as an energy signal Z. The other A / D converter 172b receives the voltage value (analog value) X1 output from the first calculation unit 130, converts it into a digital value, and outputs it. The position calculator 173 receives the digital value output from each of the A / D converter 172a and the A / D converter 172b, and obtains the ratio (X1 / (X1 + X2)) of these two digital values. This ratio is output as a position signal X. This position signal X represents the light incident position on the light receiving surface of the photodetector 110.
[0022]
The pulse height discriminator 174 receives the voltage value output from the adder 171, compares the voltage value with a predetermined threshold value, and the energy of light incident on the light receiving surface of the photodetector 110 is a predetermined value. It is determined by energy discrimination whether it should be detected. The control signal generator 175 receives the result of determination by the wave height discriminator 174, and only when it is determined that the light has a wavelength to be detected, the A / D converter 172a and the A / D converter 172b. A control signal T for instructing each A / D conversion operation is output.
[0023]
Next, the configuration of the photodetector 110 that is preferably used in the position detection apparatus 1 according to the first embodiment will be described. FIG. 2 is a cross-sectional view illustrating the configuration and operation of the photodetector 110 of the position detection device 1 according to the first embodiment. The photodetector 110 shown in this figure includes 2M scintillators 111. ₁ ~ 111 _2M And a photomultiplier tube 112. 2M scintillators 111 ₁ ~ 111 _2M Each is made of, for example, NaI (Tl) or BGO crystal, and is one-dimensionally arranged on the photoelectric conversion surface (not shown) of the photomultiplier tube 112. In the photomultiplier tube 112, M anode electrodes 113 are provided. ₁ ~ 113 _M Are one-dimensionally arranged. M anode electrodes 113 ₁ ~ 113 _M Arrangement direction and 2M scintillators 111 ₁ ~ 111 _2M Are parallel to each other. Each anode electrode 113 _m Is the output terminal P _m Connected with.
[0024]
As shown by the broken line arrow in this figure, for example, the scintillator 111 _Five When radiation is incident on the scintillator 111, _Five More scintillation pulse light is generated. The scintillation pulse light enters the photoelectric conversion surface of the photomultiplier tube 112, and photoelectrons are generated from the photoelectric conversion surface. Then, the photoelectrons are multiplied by a dynode (not shown), and a number of secondary electrons generated by the multiplication are M anode electrodes 113. ₁ ~ 113 _M Either of the above is reached. At this time, the M anode electrodes 113 ₁ ~ 113 _M The distribution of the number of secondary electrons arriving at is determined by the scintillator 111 where the radiation is incident. _Five Can be approximated by a Gaussian distribution centered on a position corresponding to the position of. Therefore, M anode electrodes 113 ₁ ~ 113 _M Of these, the anode electrode 113 _Three Output terminal P connected to _Three More current is output and the adjacent output terminals P ₂ And output terminal P _Four In some cases, more current is output.
[0025]
As described above, when light is incident on the light receiving surface of the photodetector 110, M output terminals P are selected according to the light incident position. ₁ ~ P _M A current signal is output from any one of the output terminals. Output terminal P at one end ₁ The output current signal is input to the amplifier 131 of the first arithmetic unit 130. Output terminal P at the other end _M The output current signal is input to the amplifier 141 of the second arithmetic unit 140. Other (M-2) output terminals P ₂ ~ P _M-1 The current signal output from each is input to the amplifier 132 of the first arithmetic unit 130 or the amplifier 142 of the second arithmetic unit 140 via the resistance chain circuit 120. The current value input to each of the amplifier 132 and the amplifier 142 is (M−2) output terminals P. ₂ ~ P _M-1 This corresponds to the distribution of the current value output from each.
[0026]
In the first arithmetic unit 130, a voltage value corresponding to the current value input to the amplifier 131 is output from the amplifier 131, and a voltage value corresponding to the current value input to the amplifier 132 is output from the amplifier 132. The voltage values output from the respective amplifiers 132 are added by the adder 135, and the voltage value X <b> 1 as the addition result is output from the adder 135. In the second arithmetic unit 140, a voltage value corresponding to the current value input to the amplifier 141 is output from the amplifier 141, and a voltage value corresponding to the current value input to the amplifier 142 is output from the amplifier 142. The voltage values output from each of the amplifiers 142 are added by the adder 145, and the voltage value X2 as the addition result is output from the adder 145.
[0027]
The voltage value X1 output from the adder 135 of the first calculation unit 130 and the voltage value X2 output from the adder 145 of the second calculation unit 140 are input to the position calculation unit 170, respectively. In the position calculator 170, the input voltage value X1 and voltage value X2 are added by the adder 171. Based on this addition result, when the wave height discriminator 174 determines that the light incident on the light detector 110 has a predetermined energy, the control signal T output from the control signal generator 175 is indicated. Based on this, the A / D conversion operations of the A / D converter 172a and the A / D converter 172b are executed.
[0028]
The voltage value (added value of X1 and X2) output from the adder 171 is converted into a digital value by the A / D converter 172a, and this digital value is output as the energy signal Z. The voltage value X1 is converted into a digital value by the A / D converter 172b. The digital value output from the A / D converter 172b and the digital value output from the A / D converter 172a are input to the position calculator 173, and the position calculator 173 outputs the two digital values. A value ratio (X1 / (X1 + X2)) is obtained, and this ratio is output as the position signal X. This position signal X represents the light incident position on the light receiving surface of the photodetector 110.
[0029]
In the position detection device 1 according to the first embodiment described above, (M−3) resistors R included in the resistor chain circuit 120. ₂ ~ R _M-2 The respective resistance values, the multiplication factors of the amplifier 131 and the amplifier 132 included in the first calculation unit 130, and the multiplication factors of the amplifier 141 and the amplifier 142 included in the second calculation unit 140 are appropriately set. . As a result, the position detection device 1 has a simple configuration and is excellent in both position resolution and energy signal uniformity.
[0030]
(Second Embodiment)
Next, a second embodiment of the position detection apparatus according to the present invention will be described. FIG. 3 is a schematic configuration diagram of the position detection device 2 according to the second embodiment. The position detecting device 2 shown in this figure detects a two-dimensional position where light is incident on the light receiving surface of the photodetector 210. In addition to the photodetector 210, the position detecting device 2 includes a resistor chain circuit 220, a first calculation. Unit 230, second calculation unit 240, third calculation unit 250, fourth calculation unit 260, and position calculation unit 270.
[0031]
The photodetector 210 has M × N output terminals P corresponding to a two-dimensional position on the light receiving surface that receives light (including radiation). _1,1 ~ P _{M, N} Is provided. However, M and N are integers of 4 or more. M × N output terminals P _1,1 ~ P _{M, N} Output terminal P _1,1 , Output terminal P _{1, N} , Output terminal P _{M, 1} And output terminal P _{M, N} Each corresponds to each corner of the light receiving surface. The photodetector 210 includes M × N output terminals P according to the light incident position on the light receiving surface. _1,1 ~ P _{M, N} A current signal is output from one or more of the output terminals. In the following description, M = N = 8.
[0032]
FIG. 4 is a configuration diagram of the photodetector 210 of the position detection device 2 according to the second embodiment. This photodetector 210 is a two-dimensional position detection type photomultiplier tube 212 in which 8 × 16 scintillators 211 are two-dimensionally arranged on the photoelectric conversion surface. The photodetector 210 has 8 × 8 output terminals P. _1,1 ~ P _8,8 Corresponding to each, an anode electrode (not shown) is provided.
[0033]
FIG. 5 is a configuration diagram of the resistance chain circuit 220 of the position detection device 2 according to the second embodiment. This figure shows 8 × 8 output terminals P of the photodetector 210. _1,1 ~ P _8,8 A resistor (resistor symbol in the figure) provided between these output terminals is shown together with each position (square mark in the figure). Resistor chain circuit 220 includes a cascaded resistor R _1,1 ~ R _1,7 Cascaded resistor R _2,1 ~ R _2,7 Cascaded resistor R _3,1 ~ R _3,7 Cascaded resistor R _4,2 ~ R _4,6 Cascaded resistor R _5,2 ~ R _5,6 Cascaded resistor R _6,1 ~ R _6,7 Cascaded resistor R _7,1 ~ R _7,7 Cascaded resistor R _8,1 ~ R _8,7 Cascaded resistor R _1.a ~ R _{7, a} Cascaded resistor R _{1, b} ~ R _{7, b} Cascaded resistor R _{1, c} ~ R _{7, c} , And cascaded resistors R _{1, d} ~ R _{7, d} have.
[0034]
Resistor R _{m, n} (Where m is an integer from 1 to 8 and n is an integer from 2 to 6) _{m, n} And output terminal P _{m, n + 1} Between. Resistor R _{m, a} (M is an integer from 2 to 6) is the output terminal P _{m, 2} And output terminal P _{m + 1,2} Between. Resistor R _{m, b} (M is an integer from 2 to 6) is the output terminal P _{m, 7} And output terminal P _{m + 1,7} Between. Resistor R _{m, c} (M is an integer from 2 to 6) is the output terminal P _{m, 1} And output terminal P _{m + 1,1} Between. Resistor R _{m, d} (M is an integer from 2 to 6) is the output terminal P _{m, 8} And output terminal P _{m + 1,8} Between. Also,
Resistor R _2,1 Is the resistor R _{1, a} And resistor R _{2, a} Connection point and output terminal P _2,2 Between. Resistor R _2,7 Is the resistor R _{1, b} And resistor R _{2, b} Connection point and output terminal P _2,7 Between. Resistor R _3,1 Is the resistor R _{2, a} And resistor R _{3, a} Connection point and output terminal P _3,2 Between. Resistor R _3,7 Is the resistor R _{2, b} And resistor R _{3, b} Connection point and output terminal P _3,7 Between. Resistor R _6,1 Is the resistor R _{5, a} And resistor R _{6, a} Connection point and output terminal P _6,2 Between. Resistor R _6,7 Is the resistor R _{5, b} And resistor R _{6, b} Connection point and output terminal P _6,7 Between. Resistor R _7,1 Is the resistor R _{6, a} And resistor R _{7, a} Connection point and output terminal P _7,2 Between. Resistor R _7,7 Is the resistor R _{6, b} And resistor R _{7, b} Connection point and output terminal P _7,7 Between.
[0035]
FIG. 6 is a configuration diagram of the first calculation unit 230, the second calculation unit 240, the third calculation unit 250, the fourth calculation unit 260, and the position calculation unit 270 of the position detection device 2 according to the second embodiment.
[0036]
As shown in FIGS. 5 and 6, the output terminal P of the photodetector 210. _1,1 Are directly connected to the input terminal of the amplifier 231 of the first arithmetic unit 230. Output terminal P of photodetector 210 _1,2 Is the resistor R _1,1 To the input terminal of the amplifier 232 of the first arithmetic unit 230. Output terminal P of photodetector 210 _2,1 Is the resistor R _{1, c} Is connected to the input terminal of the amplifier 233 of the first arithmetic unit 230. Output terminal P of photodetector 210 _2,2 Is the resistor R _2,1 And resistor R _{1, a} Is connected to the input terminal of the amplifier 234 of the first arithmetic unit 230.
[0037]
Output terminal P of photodetector 210 _1,8 Is directly connected to the input terminal of the amplifier 241 of the second arithmetic unit 240. Output terminal P of photodetector 210 _1,7 Is the resistor R _1,7 Is connected to the input terminal of the amplifier 242 of the second arithmetic unit 240. Output terminal P of photodetector 210 _2,8 Is the resistor R _{1, d} Is connected to the input terminal of the amplifier 243 of the second arithmetic unit 240. Output terminal P of photodetector 210 _2,7 Is the resistor R _2,7 And resistor R _{1, b} Is connected to the input terminal of the amplifier 244 of the second arithmetic unit 240.
[0038]
Output terminal P of photodetector 210 _8,1 Is directly connected to the input terminal of the amplifier 251 of the third arithmetic unit 250. Output terminal P of photodetector 210 _8,2 Is the resistor R _8,1 To the input terminal of the amplifier 252 of the third arithmetic unit 250. Output terminal P of photodetector 210 _7,1 Is the resistor R _{7, c} To the input terminal of the amplifier 253 of the third arithmetic unit 250. Output terminal P of photodetector 210 _7,2 Is the resistor R _7,1 And resistor R _{7, a} To the input terminal of the amplifier 254 of the third arithmetic unit 250.
[0039]
Output terminal P of photodetector 210 _8,8 Is directly connected to the input terminal of the amplifier 261 of the fourth arithmetic unit 260. Output terminal P of photodetector 210 _8,7 Is the resistor R _8,7 Is connected to the input terminal of the amplifier 262 of the fourth arithmetic unit 260. Output terminal P of photodetector 210 _7,8 Is the resistor R _{7, d} Is connected to the input terminal of the amplifier 263 of the fourth arithmetic unit 260. Output terminal P of photodetector 210 _7,7 Is the resistor R _7,7 And resistor R _{7, b} Is connected to the input terminal of the amplifier 264 of the fourth arithmetic unit 260.
[0040]
As illustrated in FIG. 6, the first arithmetic unit 230 includes an amplifier 231, an amplifier 232, an amplifier 233, an amplifier 234, and an adder 235. The input terminal of the amplifier 231 is the output terminal P of the photodetector 210. _1,1 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 232 is the output terminal P of the photodetector 210. _1,2 Resistor R _1,1 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 233 is the output terminal P of the photodetector 210. _2,1 Resistor R _{1, c} And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 234 is the output terminal P of the photodetector 210. _2,2 Resistor R _2,1 And resistor R _{1, a} And a voltage value corresponding to the current value input to the input terminal is output. The adder 235 receives the voltage values output from the four amplifiers 231 to 234, adds the voltage values, and outputs a voltage value A representing the addition result from the output terminal.
[0041]
The second arithmetic unit 240 includes an amplifier 241, an amplifier 242, an amplifier 243, an amplifier 244, and an adder 245. The input terminal of the amplifier 241 is the output terminal P of the photodetector 210. _1,8 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 242 is the output terminal P of the photodetector 210. _1,7 Resistor R _1,7 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 243 is the output terminal P of the photodetector 210. _2,8 Resistor R _{1, d} And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 244 is the output terminal P of the photodetector 210. _2,7 Resistor R _2,7 And resistor R _{1, b} And a voltage value corresponding to the current value input to the input terminal is output. The adder 245 receives the voltage values output from the four amplifiers 241 to 244, adds the voltage values, and outputs a voltage value B representing the addition result from the output terminal.
[0042]
The third arithmetic unit 250 includes an amplifier 251, an amplifier 252, an amplifier 253, an amplifier 254, and an adder 255. The input terminal of the amplifier 251 is the output terminal P of the photodetector 210. _8,1 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 252 is the output terminal P of the photodetector 210. _8,2 Resistor R _8,1 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 253 is the output terminal P of the photodetector 210. _7,1 Resistor R _{7, c} And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 254 is the output terminal P of the photodetector 210. _7,2 Resistor R _7,1 And resistor R _{7, a} And a voltage value corresponding to the current value input to the input terminal is output. The adder 255 receives the voltage values output from the four amplifiers 251 to 254, adds the voltage values, and outputs a voltage value C representing the addition result from the output terminal.
[0043]
The fourth arithmetic unit 260 includes an amplifier 261, an amplifier 262, an amplifier 263, an amplifier 264, and an adder 265. The input terminal of the amplifier 261 is the output terminal P of the photodetector 210. _8,8 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 262 is the output terminal P of the photodetector 210. _8,7 Resistor R _8,7 And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 263 is the output terminal P of the photodetector 210. _7,8 Resistor R _{7, d} And a voltage value corresponding to the current value input to the input terminal is output. The input terminal of the amplifier 264 is the output terminal P of the photodetector 210. _7,7 Resistor R _7,7 And resistor R _{7, b} And a voltage value corresponding to the current value input to the input terminal is output. The adder 265 receives the voltage values output from the four amplifiers 261 to 264, adds these voltage values, and outputs a voltage value D representing the addition result from the output terminal.
[0044]
The position calculation unit 270 includes a voltage value A output from the first calculation unit 230, a voltage value B output from the second calculation unit 240, a voltage value C output from the third calculation unit 250, and a fourth value. Based on the voltage value D output from the calculation unit 260, the light incident position on the light receiving surface of the photodetector 210 is obtained. The position calculator 170 includes adders 271a to 271c, A / D converters 272a to 272c, position calculators 273b and 273c, a wave height discriminator 274, and a control signal generator 275.
[0045]
The adder 271a includes a voltage value A output from the first calculation unit 230, a voltage value B output from the second calculation unit 240, a voltage value C output from the third calculation unit 250, and a fourth calculation. The voltage value D output from the unit 260 is input, and a voltage value corresponding to the sum of these four voltage values A to D is output. The A / D converter 272a receives the voltage value (analog value) output from the adder 271a, converts it into a digital value, and outputs this digital value as the energy signal Z.
[0046]
The adder 271b receives the voltage value A output from the first calculation unit 230 and the voltage value B output from the second calculation unit 240, and a voltage corresponding to the sum of these two voltage values A and B. Output the value. The A / D converter 272b receives the voltage value (analog value) output from the adder 271b, converts it into a digital value, and outputs it. The position calculator 273b receives the digital values output from the A / D converter 272a and the A / D converter 272b, and obtains the ratio of these two digital values ((A + B) / (A + B + C + D)). This ratio is output as a position signal X. This position signal X represents the X coordinate value of the light incident position on the light receiving surface of the photodetector 210.
[0047]
The adder 271c receives the voltage value A output from the first calculation unit 230 and the voltage value C output from the third calculation unit 250, and a voltage corresponding to the sum of these two voltage values A and C. Output the value. The A / D converter 272c receives the voltage value (analog value) output from the adder 271c, converts it into a digital value, and outputs it. The position calculator 273c receives the digital value output from each of the A / D converter 272a and the A / D converter 272c, and obtains the ratio ((A + C) / (A + B + C + D)) of these two digital values. This ratio is output as the position signal Y. This position signal Y represents the Y coordinate value of the light incident position on the light receiving surface of the photodetector 210.
[0048]
The pulse height discriminator 274 receives the voltage value output from the adder 271a, compares the voltage value with a predetermined threshold value, and the energy of light incident on the light receiving surface of the photodetector 210 is a predetermined value. It is determined by energy discrimination whether it should be detected. The control signal generator 275 receives the result of the determination by the wave height discriminator 274 and only determines that the A / D converter 272a to 272c has an A / D signal when it is determined that the light has a wavelength to be detected. A control signal T for instructing the conversion operation is output.
[0049]
Next, the operation of the position detection device 2 according to the second embodiment will be described. When light is incident on the light receiving surface of the photodetector 210, 8 × 8 output terminals P corresponding to the light incident position. _1,1 ~ P _8,8 A current signal is output from any one of the output terminals.
[0050]
Output terminal P in the upper left corner _1,1 The output current signal is input to the amplifier 231 of the first arithmetic unit 230. Output terminal P in the upper right corner _1,8 The output current signal is input to the amplifier 241 of the second arithmetic unit 240. Output terminal P in the lower left corner _8,1 The output current signal is input to the amplifier 251 of the third arithmetic unit 250. Output terminal P in the lower right corner _8,8 The output current signal is input to the amplifier 261 of the fourth calculation unit 260.
[0051]
Six output terminals P on the top side _1,2 ~ P _1,7 The current signal output from each is connected to a cascaded resistor R _1,1 ~ R _1,7 Then, the signal is input to the amplifier 232 of the first arithmetic unit 230 or the amplifier 242 of the second arithmetic unit 240. The current value input to each of the amplifier 232 and the amplifier 242 has six output terminals P. _1,2 ~ P _1,7 This corresponds to the distribution of the current value output from each.
[0052]
Six output terminals P at the bottom side _8,2 ~ P _8,7 The current signal output from each is connected to a cascaded resistor R _8,1 ~ R _8,7 Then, the signal is input to the amplifier 252 of the third arithmetic unit 250 or the amplifier 262 of the fourth arithmetic unit 260. The current value input to each of the amplifier 252 and the amplifier 262 has six output terminals P. _8,2 ~ P _8,7 This corresponds to the distribution of the current value output from each.
[0053]
Six output terminals P on the leftmost side _2,1 ~ P _7,1 The current signal output from each is connected to a cascaded resistor R _{1, c} ~ R _{7, c} Then, the signal is input to the amplifier 233 of the first arithmetic unit 230 or the amplifier 253 of the third arithmetic unit 250. The current value input to each of the amplifier 233 and the amplifier 253 is six output terminals P. _2,1 ~ P _7,1 This corresponds to the distribution of the current value output from each.
[0054]
Six output terminals P on the rightmost side _2,8 ~ P _7,8 The current signal output from each is connected to a cascaded resistor R _{1, d} ~ R _{7, d} Then, the signal is input to the amplifier 243 of the second calculation unit 240 or the amplifier 263 of the fourth calculation unit 260. The current value input to each of the amplifier 243 and the amplifier 263 has six output terminals P. _2,8 ~ P _7,8 This corresponds to the distribution of the current value output from each.
[0055]
Other 6 × 6 output terminals P _{m, n} (M = 2 to 7, n = 2 to 7) The current signals output from the respective resistors R are included in the resistor chain circuit 220. _{m, n} (M = 2-7, n = 2-7), resistor R _{m, a} (M = 1-7) and resistor R _{m, b} Through a resistor network consisting of (m = 1-7), the amplifier 234 of the first arithmetic unit 230, the amplifier 244 of the second arithmetic unit 240, the amplifier 254 of the third arithmetic unit 250 or the amplifier 264 of the fourth arithmetic unit 260. Enter. The current value input to each of the amplifier 234, the amplifier 244, the amplifier 254, and the amplifier 264 is 6 × 6 output terminals P. _{m, n} (M = 2 to 7, n = 2 to 7) This corresponds to the distribution of the current values output from each.
[0056]
Then, in the first arithmetic unit 230, a voltage value corresponding to the current value input to the amplifier 231 is output from the amplifier 231, and a voltage value corresponding to the current value input to the amplifier 232 is output from the amplifier 232, to the amplifier 233. A voltage value corresponding to the input current value is output from the amplifier 233, and a voltage value corresponding to the current value input to the amplifier 234 is output from the amplifier 234. The voltage values output from each of these four amplifiers 231 to 234 are added by the adder 235, and the voltage value A as a result of the addition is output from the adder 235.
[0057]
In the second arithmetic unit 240, a voltage value corresponding to the current value input to the amplifier 241 is output from the amplifier 241, and a voltage value corresponding to the current value input to the amplifier 242 is output from the amplifier 242 and input to the amplifier 243. A voltage value corresponding to the current value is output from the amplifier 243, and a voltage value corresponding to the current value input to the amplifier 244 is output from the amplifier 244. The voltage values output from each of these four amplifiers 241 to 244 are added by the adder 245, and the voltage value B as the addition result is output from the adder 245.
[0058]
In the third arithmetic unit 250, a voltage value corresponding to the current value input to the amplifier 251 is output from the amplifier 251, and a voltage value corresponding to the current value input to the amplifier 252 is output from the amplifier 252 and input to the amplifier 253. A voltage value corresponding to the current value is output from the amplifier 253, and a voltage value corresponding to the current value input to the amplifier 254 is output from the amplifier 254. The voltage values output from the four amplifiers 251 to 254 are added by the adder 255, and the voltage value C as a result of the addition is output from the adder 255.
[0059]
In the fourth arithmetic unit 260, a voltage value corresponding to the current value input to the amplifier 261 is output from the amplifier 261, and a voltage value corresponding to the current value input to the amplifier 262 is output from the amplifier 262 and input to the amplifier 263. A voltage value corresponding to the current value is output from the amplifier 263, and a voltage value corresponding to the current value input to the amplifier 264 is output from the amplifier 264. The voltage values output from the four amplifiers 261 to 264 are added by the adder 265, and the voltage value D as a result of the addition is output from the adder 265.
[0060]
The voltage value A output from the adder 235 of the first calculation unit 230, the voltage value B output from the adder 245 of the second calculation unit 240, and the voltage value C output from the adder 255 of the third calculation unit 250 The voltage value D output from the adder 265 of the fourth calculation unit 260 is input to the position calculation unit 270. Then, the sum of the input voltage values A to D is obtained by the adder 271a of the position calculation unit 270. Based on this addition result, when the wave height discriminator 274 determines that the light incident on the photodetector 210 is of a predetermined energy, the control signal T output from the control signal generator 275 is indicated. Based on this, the A / D conversion operations of the A / D converters 272a to 272c are executed.
[0061]
The voltage value (A + B + C + D) output from the adder 271a is converted into a digital value by the A / D converter 272a, and this digital value is output as the energy signal Z.
[0062]
The voltage value A and the voltage value B input to the position calculation unit 270 are added by the adder 271b, and the voltage value (A + B) that is the added value is converted into a digital value by the A / D converter 272b. The digital value output from the A / D converter 272b and the digital value output from the A / D converter 272a are input to the position calculator 273b, and the position calculator 273b outputs the two digital values. A value ratio ((A + B) / (A + B + C + D)) is obtained, and this ratio is output as the position signal X. This position signal X represents the X coordinate value of the light incident position on the light receiving surface of the photodetector 210.
[0063]
The voltage value A and the voltage value C input to the position calculation unit 270 are added by the adder 271c, and the voltage value (A + C) that is the added value is converted into a digital value by the A / D converter 272c. The digital value output from the A / D converter 272c and the digital value output from the A / D converter 272a are input to the position calculator 273c, and the position calculator 273c outputs the two digital values. A value ratio ((A + C) / (A + B + C + D)) is obtained, and this ratio is output as the position signal Y. This position signal Y represents the Y coordinate value of the light incident position on the light receiving surface of the photodetector 210.
[0064]
In the position detection device 2 according to the second embodiment described above, the resistance value of each resistor included in the resistance chain circuit 220, the multiplication factor of each of the amplifiers 231 to 234 included in the first calculation unit 230, and the second calculation Multiplication factors of the amplifiers 241 to 244 included in the unit 240, multiplication factors of the amplifiers 251 to 254 included in the third calculation unit 250, and multiplication factors of the amplifiers 261 to 264 included in the fourth calculation unit 260, respectively. Is set appropriately. As a result, the position detection device 2 has a simple configuration and is excellent in both position resolution and energy signal uniformity.
[0065]
Next, an example of the position detection device 2 according to the second embodiment will be described in comparison with a comparative example. The position detection apparatus of the example has the same configuration as that according to the second embodiment described above. The position detection device of Comparative Example 1 has the configuration described as the prior art 2 in the above-mentioned section of the prior art, and a resistance chain circuit and an amplifier between the photodetector and the position calculation unit are shown in FIG. It is what The position detection device of Comparative Example 2 has the configuration described as the prior art 3 in the above-described prior art section, and is output from the output terminals corresponding to the vicinity of the light receiving surface and the vicinity of the center of the photodetector. Current signals are taken out independently from each other and processed, and the result of the signal processing is switched and output.
[0066]
FIG. 7 is a configuration diagram of a resistance chain circuit of the position detection device of the first comparative example. As shown in this figure, in the resistance chain circuit of the position detection device of Comparative Example 1, the output terminal P of the photodetector is used. _{m, n} And P _{m, n + 1} (M = 1 to 3, 6 to 8, n = 1 to 7) are provided with resistors, and the output terminal P of the photodetector _{m, n} And P _{m, n + 1} (M = 4, 5, n = 2 to 6) are provided with resistors, and the output terminal P of the photodetector _{m, n} And P _{m + 1, n} (M = 1 to 7, n = 1, 8). Also, the output terminal P of the photodetector _1,1 Is connected to the input terminal of the amplifier 340 via a resistor, and a voltage value A corresponding to the current value input to the amplifier 340 is output from the amplifier 340. Photodetector output terminal P _1,8 Is connected to the input terminal of the amplifier 350 through a resistor, and a voltage value B corresponding to the current value input to the amplifier 350 is output from the amplifier 350. Photodetector output terminal P _8,1 Is connected to the input terminal of the amplifier 360 via a resistor, and a voltage value C corresponding to the current value input to the amplifier 360 is output from the amplifier 360. Photodetector output terminal P _8,8 Is connected to the input terminal of the amplifier 370 via a resistor, and a voltage value D corresponding to the current value input to the amplifier 370 is output from the amplifier 370. The voltage value A output from the amplifier 340, the voltage value B output from the amplifier 350, the voltage value C output from the amplifier 360, and the voltage value D output from the amplifier 370 are shown in FIG. The position calculation unit 270 is configured to input the same position calculation unit 270, and the same processing is performed.
[0067]
Next, the results of an experiment performed using this position detection device will be described. FIG. 8 is a diagram illustrating the distribution of the position signals X and Y output from the position detection device of the embodiment. FIG. 9 is a diagram illustrating the distribution of the position signals X and Y output from the position detection device of the first comparative example. FIG. 10 is a diagram illustrating the distribution of the position signals X and Y output from the position detection device according to the second comparative example. Each figure (b) plots the point which the value of the position signal (X, Y) output from the position calculating part shows when the light detector detects light of a predetermined energy on a two-dimensional plane. The two-dimensional distribution of detection frequencies is shown in shades (the darker the frequency, the greater the frequency). Each figure (a) shows a one-dimensional distribution obtained by adding a two-dimensional distribution of radiation detection frequencies in the Y-axis direction.
[0068]
As shown in FIG. 9, in the position detection device of Comparative Example 1, the position resolution was low because the light detection sensitivity was low near the periphery of the light receiving surface of the photodetector. As shown in FIG. 10, even in the position detection device of Comparative Example 2, since the light is not dispersed and incident on the light receiving surface, the position resolution is low in the vicinity of the light receiving surface of the photodetector. On the other hand, as shown in FIG. 8, in the position detection device of the example, the position resolution was high near the periphery of the light receiving surface of the photodetector.
[0069]
As described above, the position detection device according to the present embodiment does not extract the current signals output from the output terminals corresponding to the vicinity of the light receiving surface of the light detector and the vicinity of the center of the light detector independently of each other and perform signal processing. Since both are processed together, even when the current signal output from the photodetector changes, the positional separation error that occurs near the periphery of the light receiving surface is small, and the position resolution near the periphery of the light receiving surface is degraded. Can be suppressed. Further, since the same position correction table for improving the position resolution can be used in the vicinity of the periphery and the vicinity of the center, it is easy to create and correct the position correction table. Furthermore, the current signals output from the output terminals corresponding to the vicinity of the periphery of the light receiving surface of the photodetector are processed together without taking out the signal processing independently, so the light is dispersed using an optical system. Thus, the position resolution near the periphery of the light receiving surface can be improved without being incident on the light receiving surface.
[0070]
【The invention's effect】
As described above in detail, in the position detection device according to the present invention, the current signals output from the output terminals corresponding to the vicinity of the periphery and the center of the light receiving surface of the photodetector are extracted independently from each other. Instead of being processed, both are processed together. Therefore, this position detection device has a simple configuration and is excellent in both position resolution and energy signal uniformity.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a position detection apparatus 1 according to a first embodiment.
FIG. 2 is a cross-sectional view illustrating the configuration and operation of a photodetector 110 of the position detection device 1 according to the first embodiment.
FIG. 3 is a schematic configuration diagram of a position detection device 2 according to a second embodiment.
FIG. 4 is a configuration diagram of a photodetector 210 of a position detection device 2 according to a second embodiment.
FIG. 5 is a configuration diagram of a resistance chain circuit 220 of the position detection device 2 according to the second embodiment.
6 is a configuration diagram of a first calculation unit 230, a second calculation unit 240, a third calculation unit 250, a fourth calculation unit 260, and a position calculation unit 270 of the position detection apparatus 2 according to the second embodiment. FIG.
7 is a configuration diagram of a resistance chain circuit of the position detection device of Comparative Example 1. FIG.
FIG. 8 is a diagram illustrating a distribution of position signals X and Y output from the position detection apparatus according to the embodiment.
9 is a diagram showing the distribution of position signals X and Y output from the position detection device of Comparative Example 1. FIG.
10 is a diagram showing the distribution of position signals X and Y output from the position detection device of Comparative Example 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,2 ... Position detection apparatus, 110 ... Photo detector, 120 ... Resistance chain circuit, 130 ... 1st calculating part, 140 ... 2nd calculating part, 170 ... Position calculating part, 210 ... Photo detector, 220 ... Resistance chain Circuit, 230 ... 1st operation part, 240 ... 2nd operation part, 250 ... 3rd operation part, 260 ... 4th operation part, 270 ... Position operation part.

Claims (2)

M output terminals P _{1 to} P _M are provided according to a one-dimensional position on the light receiving surface for receiving light (where M is an integer of 4 or more), and according to the light incident position on the light receiving surface. A photodetector for outputting a current signal from any one of the _M output terminals P _{1 to} P _M ;
Of the _M output terminals P _{1 to} P _M , a resistor R _m provided between the output terminal P _m and the output terminal P _{m + 1} (where m is 2 or more and (M−2) or less). Each integer.),
A first input terminal, a second input terminal, and an output terminal are provided. A first input terminal is connected to the output terminal P ₁ among the _M output terminals P _{1 to} P _M , and a second input terminal is connected to the output terminal P ₂ . A first arithmetic unit connected to the input terminal and outputting a voltage value from the output terminal based on the value of the current signal input to each of the first input terminal and the second input terminal;
A first input terminal, a second input terminal, and an output terminal are provided. The first input terminal is connected to the output terminal P _M among the _M output terminals P _{1 to} P _M , and the output terminal P _M-1 is connected to the first input terminal. A second operation unit connected to the second input terminal and outputting a voltage value from the output terminal based on the value of the current signal input to each of the first input terminal and the second input terminal;
A position calculation unit for obtaining a light incident position on the light receiving surface based on voltage values output from output terminals of the first calculation unit and the second calculation unit;
A position detection device comprising: M × N output terminals P _{1,1 to} P _{M, N} are arranged according to a two-dimensional position on the light receiving surface that receives light (where M and N are integers of 4 or more), and the light receiving surface. A photodetector that outputs a current signal from any one of the M × N output terminals P _{1,1 to} P _{M, N} according to the light incident position on the top;
Of the M × N output terminals P _{1,1 to} P _{M, N} , resistors R _{m, n} provided between the output terminal P _{m, n} and the output terminal P _{m, n + 1} ( Where m is an integer from 1 to M. n is an integer from 2 to (N-2).
Of the M × N output terminals P _{1,1 to} P _{M, N} , resistors R _{m, a} provided between the output terminal P _{m, 2} and the output terminal P _{m + 1,2} ( M is an integer of 2 or more and (M-2) or less.)
Of the M × N output terminals P _{1,1 to} P _{M, N} , a resistor R _m provided between the output terminal P _{m, N-1} and the output terminal P _{m + 1, N−1. , b} (where m is an integer of 2 or more and (M-2) or less),
Of the M × N output terminals P _{1,1 to} P _{M, N} , resistors R _{m, c} provided between the output terminal P _{m, 1} and the output terminal P _{m + 1,1} ( M is an integer of 2 or more and (M-2) or less.)
Among the M × N output terminals P _{1,1 to} P _{M, N} , resistors R _{m, d} provided between the output terminal P _{m, N} and the output terminal P _{m + 1, N} ( M is an integer of 2 or more and (M-2) or less.)
The first input terminal, a second input terminal, a third input terminal, a fourth having an input terminal and an output terminal, wherein the M × N output terminals P _{1, 1} to P M, the output terminal P ₁ of the _{N , 1} is connected to the first input terminal, the output terminal P _1,2 is connected to the second input terminal, the output terminal P _2,1 is connected to the third input terminal, and the output terminal P _2,2 is connected to the fourth input terminal. A first arithmetic unit connected to the input terminal and outputting a voltage value from the output terminal based on the value of the current signal input to each of the first to fourth input terminals;
The first input terminal, a second input terminal, a third input terminal, a fourth having an input terminal and an output terminal, wherein the M × N output terminals P _{1, 1} to P M, the output terminal P ₁ of the _{N , N} is connected to the first input terminal, output terminal P _{1, N-1} is connected to the second input terminal, output terminal P _{2, N} is connected to the third input terminal, and output terminal P _{2, N- A} second input unit connected to the first input terminal, and a voltage value output from the output terminal based on the value of the current signal input to each of the first to fourth input terminals;
A first input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal, and an output terminal P _M among the M × N output terminals P _{1,1 to} P _{M, N , 1} is connected to the first input terminal, the output terminal P _{M, 2} is connected to the second input terminal, the output terminal P _M-1,1 is connected to the third input terminal, and the output terminal P _M-1, A fourth input terminal is connected to ₂ , and a third calculation unit that outputs a voltage value from the output terminal based on the value of the current signal input to each of the first to fourth input terminals;
A first input terminal, a second input terminal, a third input terminal, a fourth input terminal, and an output terminal, and an output terminal P _M among the M × N output terminals P _{1,1 to} P _{M, N , N} is connected to the first input terminal, output terminal P _{M, N-1} is connected to the second input terminal, output terminal P _{M-1, N} is connected to the third input terminal, and output terminal P _M- 4, a fourth input terminal is connected to _N-1 , and a fourth arithmetic unit that outputs a voltage value from the output terminal based on the value of the current signal input to each of the first to fourth input terminals;
A position calculation unit that obtains a light incident position on the light receiving surface based on voltage values output from output terminals of the first calculation unit, the second calculation unit, the third calculation unit, and the fourth calculation unit, respectively. When,
A position detection device comprising:

Images