JPH01100415A - Distance detector - Google Patents

Abstract

PURPOSE:To detect distances in a broad area at high distance resolution, by inputting lights from materials to be measured at a long distance and a short distance as light points into different light receiving area, and selecting the output of a photocurrent from the light receiving area, where the light is inputted most intensely. CONSTITUTION:In a plurality of light receiving areas 520-524 of a semiconductor position detector 5, into which lights are inputted from a materials to be measured, one of each pair of signal lead-out electrodes is aligned with others in neighboring positions. The intervals between the signal lead-out electrodes sequentially become large by equal time. Photocurrents for said each pair of the signal lead-out electrodes are sent to adding circuit U9-U13. When the incident light spot is deviated into the neighboring light receiving area, the decreased amount of the photocurrent is corrected. The outputs of adding circuit U10-U12 are imparted to sample holding circuits U18-U20 and further inputted into comparator circuits U24-U26. In which light receiving area the signal light reflected from the material to be measured hits most intensely is judged. Then, signals G1, G2 and G3 are outputted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a semiconductor device detector that receives light from an object to be measured as a light spot and detects the position of this light spot. The present invention relates to a distance detection device that detects the distance to an object based on the output from the device.

[Conventional technology]

Conventionally, active distance detection devices project light from a light source onto an object to be measured, and detect the distance to the object by receiving the reflected light with a semiconductor device detector installed at a certain distance from the light source. Are known.

FIG. 4 is an explanatory diagram of the optical system of such a distance detection device.

As shown in the figure, light from a light source 1 such as a light emitting diode (LED) is irradiated onto an object to be measured 3 via a condenser lens 2 . The reflected light from the object to be measured 3 is collected by a light receiving lens 4 and is incident on a light receiving section (not shown) of a semiconductor device detector 5 as a light spot.

Here, the base line length is B, the distance to the object to be measured 3 is L, the distance between the light receiving lens 4 and the semiconductor device detector 5 (imaging distance) is f, and the semiconductor device is detected from the optical axis of the light receiving lens 4. When the distance to the light spot position (focusing center position) SP on the device 5 (the amount of movement of the spot light) is represented by X, the following equation (1) holds true.

x - (f 11B) /L - (1
) Therefore, in FIG. 4, if the values of x, f, and B are known, the distance to the object to be measured 3 can be determined.

FIG. 5 is a detailed cross-sectional configuration diagram of the one-dimensional semiconductor device detector 5 shown in FIG. As shown, the high resistance intrinsic (i
A p-type paper layer 52 in which p-type impurities are uniformly diffused is formed on the surface side of the silicon substrate 51, and forms a light receiving portion as a p-n junction diode. Further, on the back side of the silicon substrate 51, an n+
A mold conductive layer 53 is formed, to which an electrode 54 is in ohmic contact. A pair of signal extraction electrodes 55a are provided at both ends of the p-type paper layer (light receiving section) 52 on the front side.

55b is arranged, and the currents I and I are taken from here.
B It is designed to be taken out.

Now, assume that light from the object to be measured 3 is incident as a light spot at a position SP on the p-type paper anti-layer 52, and that this position SP is a distance X away from the electrode 55a.

Further, the distance between the electrodes 55a and 55b is C, the resistance value of the p-type paper anti-layer 52 between them is R6, the resistance of the p-type paper anti-layer 52 between the position SP and the electrode 55a is R, and the If the photocurrent generated by the incidence of is summer, then the current 1
, I holds the following 2〇AB.

I -1φ(Rc-Rx)/Rc O 1-1-R/Ro-(2) B Ox Here, since the resistance value in the p-type paper anti-layer 52 is proportional to its length, the above equation (2) is The equation (3) below is obtained.

1 -1 ・(C-x)/C 1-I -xlC... (3) O Therefore, from the above formula (3), (IA-IB)/ (IA+IB) -1-2x/C... (4) Since power is obtained, the current is 1 regardless of the intensity of the incident light.
- The light incident position SP can be calculated from the value of IB.

FIG. 6 is a diagram showing the distance detection optical system when the distance measurement range is set from LN to Lp. The luminous flux of the light source 1 is condensed by a condensing lens 2, and the object to be measured 3 is irradiated. The reflected light from the object to be measured 3 is condensed by a light receiving lens 4 arranged at a distance of a base line length B from the condensing lens 2. The semiconductor device detector 5 is located at a condensing position at a distance f from the light receiving lens 4 (
light spot position).

Here, the closest distance (limit on the short distance side) and the farthest distance (limit on the long distance side) within the range measurement range are respectively LN and L, and the distance to the object to be measured 3 is L. In addition, the distance from the optical axis of the light receiving lens 4 to one end of the light receiving part of the semiconductor device detector 5 is defined as Xp, and the distance to the other end is defined as X.
N, the distance from the light spot position SP where the reflected light from the object to be measured 3 is focused by the light receiving lens 4 to the optical axis of the light receiving lens 4 is X, and the distance from the light spot position SP to the semiconductor device detector 5 is
Let xl be the distance to one end of the light receiving section of the semiconductor device detector 5, and C be the length of the light receiving section (the distance between the pair of electrodes) of the semiconductor device detector 5, then the following relational expressions hold true.

f·B (5) P Lp x −〇+XF■f11B/LN (6) Therefore, the following equation (7) is obtained from the above equations (5) and (6).

In addition, in Fig. 6, Xt 4)(-Xp -f-B (1/L-1/LF)
...The relational expression (8) can also be obtained.

Next, the position resolution of the semiconductor device detector 5 is determined by ΔX1 distance L
Let the distance resolution at N and ΔL be ΔL and Δ
Let Lp be LN, and let the relationship be LP /L, N-m
−(9), the following relational expression is obtained.

... (11) ΔX+xF=lllfΦB/(m・LN−ΔLF)...
- (12) From equations (11) and (12), the distance resolutions ΔLN and ΔLp are shown in equations (13) and (14), respectively.

ΔLN−Δx or LN/(Δx IL N 10f ψB
)...(13) ΔL -m ・'ΔX-L2 P N /(m・ΔX・LN+f-B) ...(14) Taking the ratio of equations (13) and (14), we get the following: (1
5) Equation is obtained.

ΔL /ΔL-ms(ΔX8LN+fφB)N/(mfistΔxfistLN+f11B)...(15) In formula (15), when the condition of m"ΔX life LN (f・B holds true, this can be converted into the following (16) ) can be approximated by the equation.

ΔL /ΔL +m2 −(16)N From the equation (16), it can be seen that the distance resolution ΔL on the long distance side deteriorates significantly when m shown in the above-mentioned equation (9) is large.

[Problems to be Solved by the Invention] In other words, the larger the measurable range from the closest distance to the farthest distance, the lower the resolution when the distance becomes that much longer. For this reason, for example, a position detection device that is expected to have high resolution at a short distance, such as position detection in the processing section of a laser processing machine, can be used for high resolution at a long distance, such as position detection in the movement of an automatic guided vehicle. When applied to devices that require high resolution, there is a drawback that the desired resolution cannot be obtained.

Therefore, the present invention provides a ratio of far and near critical distances (L).

An object of the present invention is to provide a distance detection device with a wide range of distance measurement, which can obtain high distance resolution on the long distance side even when the distance (L N -m ) is increased.

[Means for solving problems]

In the distance detection device according to the first invention of the present application, light from an object to be measured is incident as a light spot on a light receiving part formed on the surface side of a high-resistance semiconductor substrate containing one conductivity type impurity. A distance detection device that sometimes includes a semiconductor device detector from which a photocurrent is extracted from signal extraction electrodes arranged at both ends of the light receiving section, and detects the distance to the object to be measured from the photocurrent output of the semiconductor device detector. It is characterized by being configured as follows. That is, the light receiving section described above includes a plurality of light receiving areas each having a pair of signal extraction electrodes arranged at both ends, and the plurality of light receiving areas are arranged in a row such that one and the other of each pair of signal extraction electrodes are adjacent to each other. The intervals between the signal extraction electrodes of the plurality of light receiving areas are successively equal to each other. The distance detection device of the present invention includes a discriminating means for determining which light-receiving area is most strongly irradiated with light based on the photocurrent output from each pair of signal extraction electrodes in the plurality of light-receiving areas; selecting means for selecting the photocurrent output of the light-receiving area that is most strongly illuminated and the photocurrent output of the adjacent light-receiving area based on the discrimination result of the discrimination means; A correction means corrects the photocurrent output of the light-receiving area that is most strongly illuminated by the photocurrent output of an adjacent light-receiving area; and calculation means for determining the position of the point and calculating the distance to the object to be measured.

Further, in addition to the first invention, the light receiving section has one auxiliary light receiving area on the outside of both ends thereof in addition to the above light receiving area, and each of the auxiliary light receiving areas has a Each has a signal extraction electrode. Then, the correction means corrects the photocurrent output of the light receiving area that is most strongly illuminated, based on the photocurrent output of the light receiving area or the auxiliary light receiving area.

[Effect]

According to the configurations of the first and second inventions of the present application, the light from the object to be measured on the far side and the light from the object to be measured on the near side are incident on different light receiving areas as light spots. Therefore, each photocurrent is output from the signal extraction electrode of each light receiving area. Then, regarding the photocurrent output from each light-receiving area, it is determined which area is most strongly irradiated with light.

Therefore, the most appropriate light-receiving area is selected according to the distance to the object to be measured, and the photocurrent output is further corrected by the adjacent light-receiving area or auxiliary light-receiving area, and the distance is detected based on these.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the description of the drawings, the same elements are given the same reference numerals, and redundant description will be omitted.

FIG. 1 is a block diagram of a distance detection device according to an embodiment, and this device includes a semiconductor device detector and a signal processing circuit that processes its output signal.

As shown in the figure, in this embodiment, the first feature is that the light receiving section of the semiconductor device detector is divided into a plurality of areas (light receiving areas), and the second feature is that the photocurrent output from each light receiving area is selected. As a third feature, the photocurrent output from the selected light-receiving area that is most strongly illuminated is corrected by the photocurrent output from the adjacent light-receiving area or the auxiliary light-receiving area, and based on this, It is designed to perform predetermined arithmetic processing. Therefore, first, the configuration and operation of the semiconductor device detector will be explained in detail.

FIG. 2 is a perspective view of the semiconductor device detector, and FIG.
) is a plan view thereof, and (b) is a longitudinal sectional view. What makes this different from conventional ones is that the light receiving section formed on the front side of the semiconductor substrate is composed of multiple light receiving areas and two auxiliary light receiving areas. . n light receiving areas 52 (n is an integer of 2 or more)
□~52 and two auxiliary light receiving areas 52, 52n
+1n.

are formed by uniformly diffusing P-type impurities on the surface side of the high-resistance silicon substrate 51, and the lengths of the light-receiving areas 52□ to 52n in the longitudinal direction gradually increase. At both ends of each light receiving area 52□-52n, a pair of signal extraction electrodes 55a1-55 whose width is sufficiently narrow is provided.
5an.

55b1 to 55bn are arranged, and P between a pair of extraction electrodes is
Pattern anti-layer (light-receiving area) length 01-c.

The following relationship holds true: C2/C1-C5/C2-... -C/C-D (constant) n n-1... (17). Note that each signal extraction electrode 55a
~55a, 55bl~55bn width Wl
It is assumed that n is sufficiently narrow to be considered as W(C1.On the other hand, two auxiliary light receiving areas 52 and 52
Onil small electrodes 55 a and 55 b o, one for each signal, are also arranged at the outer ends of the electrodes, and the widths of these electrodes are also sufficiently narrow as described above.

Divide the distance measurement range into n parts, and select L and L2 from the far side.
.

■ If L, L,...L, when the semiconductor device detector 3 4 n 5 satisfies the above equation (17), the following (1
8) The relationship of equation holds true.

L /L2-wL2/L3-L3/L4-...-L/
LD (constant) n-1n (18) The characteristic feature of the present invention is that the light receiving areas 52□ to 5
An auxiliary light receiving area 52o is located outside of 2n.

52 is provided, and in this point nil is different from Japanese Patent Application No. 174225/1989, which was previously filed by the present applicant. The reason for doing this will be explained below.

Ideally, the size of the spot light focused on the light receiving portion of the semiconductor device detector by the light receiving lens 4 is infinitesimal, but in reality it is a certain finite size. Therefore,
When the spot light approaches the end of the light receiving area 52 or 52n of the semiconductor device detector shown in FIGS. 2 and 3, the signal light that deviates from the light receiving area 52□ or 52n is not photoelectrically converted; Only the signal light irradiated onto the area will be photoelectrically converted. As a result, the signal photocurrent obtained from the signal extraction electrode 55b1 or 55an becomes smaller, and the amount of change in the output value of the calculated output after performing the predetermined analog division becomes smaller with respect to the amount of change in distance. In other words, when the spot light reaches the end of the light receiving area 521 or 52n, the distance resolution deteriorates.

In order to improve this drawback, in FIG. 2, the semiconductor device detector of the present invention has auxiliary light receiving areas 5 at both outermost ends.
2 and 52 are formed at On+1. This auxiliary light receiving area 52.52
l The emitted signal light is photoelectrically converted and sent to the signal extraction electrode 55b.
and 5.5 taken from ao. Then, the photocurrent obtained from the signal extraction electrode 55b or 55ao is transferred to the signal extraction electrode 55b1 by an adding circuit described later.
Alternatively, after being added to the photocurrent obtained from 55an, calculations are performed by an analog divider. As a result, the distance resolution in this part (long range/short range side) will be significantly improved.

In the amplifier circuit connected to the semiconductor device detector 5, the light incident on the semiconductor device detector 5 includes disturbance light (for example, sunlight, etc.) in addition to the signal light.

In this case, it is common to use an AC coupling method using a current-voltage conversion resistor and a capacitor (see "Semiconductor Device Detector Catalog JP, 14, published by Hamamatsu Photonics Co., Ltd."). Due to the difference in temperature characteristics between the interelectrode resistance R of the detector 5 and the current-voltage conversion resistance,
An error occurs in the signal calculation output shown in equation (4) above. Therefore, each electrode 55ao to 55an on the high resistance silicon substrate 51 of the semiconductor device detector 5 shown in FIG.

A current-voltage conversion resistor (
By forming a resistor (not shown) and matching the temperature characteristics of the resistors, it is possible to eliminate errors in the signal calculation output.

FIG. 1 is a block diagram of a semiconductor device detector 5 applied to the present invention and a signal processing circuit dedicated thereto. In this embodiment, the light receiving portion of the semiconductor device detector 5 is separated by separation layers 58o to 58o.
583, and the relationship in equation (17) above is set to the following values.

C/C-C3/C2-2 (19) Accordingly, the distance measurement range is divided into the following numerical values according to the above-mentioned equation (18).

L/L-L2/L3-2 (20) On the semiconductor device detector 5, signal extraction electrodes 55a to 55a3 of each light receiving area 52□ to 52.

Current-voltage conversion resistor ■ in contact with 55b ~ 55b3 " is formed, and the auxiliary light receiving area 52o.

A resistor r for current-voltage conversion is formed in contact with the signal extraction electrodes 55a and 55bo of 52.

Photocurrent obtained by incident light■1゜IBl・
IAl, IB2, 1A2, 'B3, lA3 and ■3 are converted to voltage by this current-voltage conversion resistor r, AC coupled by capacitor C, and only the AC component is sent to amplifier U-U8, where it is added after amplification. ■ Transferred to arithmetic circuit U-U13.

Addition circuit U9 calculates the sum of alternating current components Bl in photocurrents I and I obtained when light enters auxiliary light receiving area 52 and light receiving area 52 of semiconductor device detector 5. By this addition, the decrease in photocurrent ■8□ when the incident light spot deviates from the light receiving area 521 toward the auxiliary light receiving area 52° is corrected. Similarly, the adder circuit U13 includes the auxiliary light receiving area 52 and the light receiving area 5.
The sum of the alternating current components of the photocurrents 1 and I obtained from 23 is calculated. This addition A3 corrects the decrease in the photocurrent ■A3 when the incident light spot deviates from the light receiving area 523 to the auxiliary light receiving area 524 side. On the other hand, adder circuits U10'U, U
is the light receiving area 52. 522.523 The intersection of photocurrents I ~ I , I ~ I BI B3
AI A3 Calculates the sum of three components. Furthermore, the outputs of the amplifier U3 and the adder circuit U are given to the adder circuit U14, and similarly the outputs of the amplifiers U, U, U and the output of the adder circuit 5B UUU are given to the adder circuit UU lOo 12' 11 15'
1B'U1□ respectively.

The output of the adder circuit U1G"" U12 is given to the sample-and-hold circuits U18 to U2o, and the signal level of the light reflected from the object to be measured 3 when the light source 1 is pulse-lit is held. The sampling signal at this time is indicated by symbol φ2 in FIG. The outputs of sample-and-hold circuits U18 to U20 are filter circuits U2□ to U23.
averaged by And filter circuit U2□~U
The output of 23 is given to comparison circuits U24 to U2B, which determine which light receiving area among the light receiving areas 52 to 523 of the semiconductor device detector 5 the signal light reflected from the object under test 3 most strongly hits. is determined, and the results are output from the AND gates as gate signals Gl, G2, and G3.

Here, for example, when the optical signal is incident on the light receiving area 521, the gate signal G1 is "H" (high level).
Therefore, the gate signals G2 and G3 become low level (L'C low level). These gate signals Gl, G2, and G3 turn on the signal line from the light receiving area where the signal light is most strongly incident in the gate circuit 22, and the output thereof is sent to the subtracting circuit 23 and the adding circuit 24. That is, the on/off state of the signal line in the gate circuit is controlled in an active high state (on state B when the gate signal becomes "H") as described below.

The adder circuit U14 calculates the sum I8 of the photocurrent Al obtained from the signal extraction electrode 55a1 of the light receiving area 52 for position detection and the photocurrent obtained from the light receiving area 52° for position detection.
2" is added to IA2. As a result, when the gate signal G1 is 'H# and the center of the spot light is near the separation layer 58., the spot light that has left the light receiving area 521 is added to the adjacent At is photoelectrically converted in the light receiving area 522, and the decrease in the signal photocurrent I can be corrected by IBZ+IA2.

The center position of the spot light is from the separation layer 581 to the light receiving area 5
When moving slightly in the direction of 22, the gate signal G1 changes to “
L", and the gate signal G2 becomes "H". At this time, the signal light that is out of the light receiving area 522 (the photocurrent obtained from the signal extraction electrode 55b2 decreases by 8 degrees) is transferred to the adjacent light receiving area 52. The sum of the signal photocurrents photoelectrically converted in □ corresponds to IB□+I At, and therefore the addition circuit U15
By executing the addition (IB1+1A1)+lB2, it is possible to correct the decrease in 'B2.

For the same reason, the addition circuits U and U1□ can correct the decrease in the signal values of I and IB3, respectively.

Here, if adder circuits U9 and U13 and adder circuit U1
If 4 to U17 are not provided, the decrease in signal current will not be corrected at the switching position of each divided ranging range, so the amount of change in the calculated output value of analog divider 26 with respect to the amount of change in distance will be This results in a decrease in distance resolution. Therefore, as is clear from the above explanation, even if the auxiliary light receiving areas 52 and 524 are not provided in this embodiment, if the adder circuits U14 to U17 are provided and the photocurrent is corrected thereby, the separation layer 58.

It can be seen that when the spot light comes near 58 degrees, the distance resolution can be sufficiently improved.

Addition circuit-U and U13 and addition circuits U14 to U17
After the signal current is corrected and the gate circuit 22 performs ON/OFF control of the signal line, the subtraction circuit 23 and the addition circuit 24 perform subtraction and addition of the signal, and the calculation output is extracted from the signal component. The signal is applied to the circuit 25, where only the signal component superimposed on the disturbance light component is extracted.

Here, the voltage level immediately before pulse lighting of the light source is recorded by sampling signal φ1, and the voltage level at the time of pulse lighting is recorded by sampling signal φ2.

By taking the difference between these two recorded values, signal components are extracted. The output of the signal component extraction circuit 25 is given to an analog divider 26, where arithmetic operations are performed and output in the form of an analog voltage. As a result, gate signal G1. Based on the output states of G2 and G3, it is possible to determine where the object to be measured exists in the distance measurement range divided into three parts, and the accurate distance to the object to be measured 3 can be obtained from the analog voltage output.

This analog calculation for distance detection can be specifically performed using the above-mentioned equations (3) and (4).

In other words, if we eliminate the distance X from equations (1) and (4) above, we obtain the following relationship: (IA-IB)/(IA+IB) -1-2fΦB/ (CΦL) (21), Current calculation value (IA-1B)/(
r + IB) is he? It can be seen that fJI is inversely proportional to the distance ML to the constant object, so the distance can be determined indirectly.

Although not shown in the figure, among the output values of the signal component extraction circuit 25, the signal level of IA+IB is monitored, and the driving circuit (on the light source 1 side)
(not shown) by controlling the analog divider 26
The calculation accuracy can be improved.

Next, the above embodiment will be explained in more detail using specific numerical values.

First, the optical conditions of the distance measuring device of the embodiment are set as follows.

f-60 (mm) B-200 [m ■] LN3 Go 750 C City] LF3- LN2-1500 (m+5) LF2-LN
l-3000C order] LF1=6000 (am) LF1/LN1-2 C1= f-B (1/L 1/Lpt) -
2 (mIl]l Δx-CI1500-4 Cμm) The resolution of the semiconductor device detector 5 changes depending on the magnitude of the signal photocurrent based on the incident light, but generally when the sum of the signal photocurrents (IA+IB) is 300 (nA), At times, the resolution ΔX
is approximately 11,500 times the electrode spacing. Therefore, Δx −
Calculate as C1/500.

When the above numerical values are substituted into the above-mentioned equation (14), the distance resolution ΔL of the farthest distance becomes as follows.

ΔLF-12 (related) ... (19) On the other hand, when a conventional semiconductor device detector is used with the same optical system, the distance resolution at the farthest distance is found as follows in the same way. .

f-B-12000 LN-w750 [m11] LF-6000C report] LP/LN-8 C-f -B (1/L -1/LF) -14 (m
m]ΔLF-83[m+*] = (
20) Therefore, comparing equations (19) and (20), we get
In this embodiment, the distance resolution on the long distance side is improved by about 7 times even when the same optical system is used, compared to when a conventional semiconductor device detector is used.

This effect can be further improved by increasing the number of divisions (number of light receiving areas) of the light receiving section of the semiconductor device detector.

The present invention is not limited to the above embodiments, and various modifications are possible.

For example, the semiconductor device detector applied to the distance detection device of the present invention is not limited to that shown in FIG. Furthermore, the semiconductor substrate is not limited to silicon, but if it is made of gallium arsenide (GaAs), for example, it can be used even under higher temperature conditions.

〔Effect of the invention〕

As described above in detail, according to the invention of the present application, the light from the object to be measured on the far side and the light from the object to be measured on the near side are respectively incident on different light receiving areas as light spots,
Therefore, each photocurrent is output from the signal extraction electrode of each light receiving area. Then, the photocurrent d from the light-receiving area that is most strongly illuminated is selected and subjected to analog calculation, so the ratio of the far and near field distances (L /L -
m) Even if N is increased, a distance detection device with a wide distance measurement range that can obtain high distance resolution on the long distance side can be obtained.

In particular, in the first invention, since the decrease in photocurrent from the light-receiving area that is most strongly illuminated is corrected by the photocurrent from the adjacent light-receiving area, when light hits near the boundary of the light-receiving area, A distance detector is obtained that can improve the resolution of .

Furthermore, in the second invention, an auxiliary light receiving area is provided outside the light receiving areas at both ends, and this photocurrent can compensate for the decrease in the photocurrent in the light receiving areas at both ends, so On either side, the effect is that the resolution can be further improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts of a distance detection device according to an embodiment of the present invention, FIG. 2 is a perspective view of a semiconductor device detector applied to an embodiment of the present invention, and FIG. 3 is shown in FIG. A plan view and a vertical sectional view of a semiconductor device detector, FIG. 4 is an explanatory diagram of the optical system of a distance detection device, FIG. 5 is a sectional view of a semiconductor device detector applied to a conventional device, and FIG. 6 is a distance measuring device. Range from LN to LP
It is an explanatory view of an optical system for distance detection when it is set to . DESCRIPTION OF SYMBOLS 1... Light source, 2... Condenser lens, 3... Measured object, 4... Light receiving lens, 5... Semiconductor device detector, 2
2... Gate circuit, 23... Subtraction circuit, 24...
Addition circuit, 25... Signal component extraction circuit, 26... Analog divider, 51... Silicon substrate, 52... Light receiving section (P-type paper layer), 52o... Auxiliary light receiving area, 5
2□~52n... Light receiving area, 52... Auxiliary light receiving area, 53... N type conductive layer, 55a, 55ao
~55a, 55b, 55bo~55bn...Signal number circle electrode, U1~U8...Amplifier, U9~U1□...
Addition circuit, U18~U2o...Sample and hold circuit, U2□~U23...Filter circuit, U24~
U26... Comparison circuit (comparator). Patent applicant Hamamatsu Photonics Co., Ltd. Representative Patent Attorney
Figure 5 Cross-sectional structure of Yoshiki Hase semiconductor device detector

Claims (1)

[Claims] 1. When light from an object to be measured is incident as a light spot on a light receiving part formed on the surface side of a high-resistance semiconductor substrate containing one conductivity type impurity, the light receiving part is A semiconductor device detector is provided from which a photocurrent is extracted from signal extraction electrodes arranged at both ends, and the distance to the object to be measured is detected by determining the incident position of the light spot from the photocurrent output of the semiconductor device detector. In the distance detection device, the light-receiving section includes a plurality of light-receiving areas each having a pair of signal extraction electrodes arranged at both ends, and one of the plurality of light-receiving areas is such that one and the other of each pair of signal extraction electrodes are adjacent to each other. The signal extraction electrodes of the plurality of light-receiving areas are arranged in a line so that the signal extraction electrodes of the plurality of light-receiving areas are sequentially arranged at equal intervals, and the photocurrent output from each pair of signal-extraction electrodes of the plurality of light-receiving areas is determining means for determining which light-receiving area is most strongly illuminated by light; a selection means for selecting a current output based on the discrimination result of the discrimination means; and a selection means for selecting the photocurrent output of the light-receiving area that is most strongly illuminated by the light-receiving area selected by the selection means; and a calculation means for determining the position of a light spot in the light receiving section from the photocurrent output selected by the selection means and corrected by the correction means and calculating the distance to the object to be measured. A distance detection device comprising: 2. The distance detection device according to claim 1, wherein the light receiving section is divided into the plurality of light receiving areas via a separation layer formed on the semiconductor substrate. 3. The distance detection device according to claim 1 or 2, wherein the signal extraction electrode is grounded via a current/voltage conversion resistor. 4. The distance detecting device according to any one of claims 1 to 3, wherein the discrimination means includes a comparison circuit that compares the levels of photocurrent outputs of the plurality of light receiving areas. 5. When light from an object to be measured is incident as a light spot on a light receiving part formed on the surface side of a high-resistance semiconductor substrate containing one conductivity type impurity, A distance detecting device comprising a semiconductor device detector from which a photocurrent is extracted from a signal extraction electrode, and detecting the distance to the object to be measured by determining the incident position of the light spot from the photocurrent output of the semiconductor device detector, The light receiving section includes a plurality of light receiving areas each having a pair of signal extraction electrodes arranged at both ends, and the plurality of light receiving areas are arranged in a line such that one and the other of each pair of signal extraction electrodes are adjacent to each other. and the intervals between the signal extraction electrodes of the plurality of light receiving areas are sequentially equal to each other, and further, the light receiving section includes at least two auxiliary light receiving areas each having at least one signal extraction electrode,
The auxiliary light-receiving areas are provided outside both ends of the light-receiving areas in the arrangement direction, and are determined based on the photocurrent output from each pair of signal extraction electrodes of the plurality of light-receiving areas. a determining means for determining whether light is shining on the photocurrent output of the plurality of light-receiving areas; a selection means that selects based on the discrimination result of the discrimination means; and a photocurrent output of the light receiving area that is most strongly illuminated by the light selected by the selection means with the photocurrent output of the adjacent light receiving area or the auxiliary light receiving area. a compensating means for correcting; and a calculating means for determining the position of a light spot in the light receiving section from the photocurrent output selected by the selecting means and corrected by the correcting means, and calculating a distance to the object to be measured. A distance detection device characterized by: 6. The distance detection device according to claim 5, wherein the light receiving section is divided into the plurality of light receiving areas and an auxiliary light receiving area via a separation layer formed on the semiconductor substrate. . 7. The distance detecting device according to claim 5 or 6, wherein the signal extraction electrode is grounded via a current/voltage conversion resistor. 8. The distance detecting device according to any one of claims 5 to 7, wherein the discrimination means includes a comparison circuit that compares the levels of photocurrent outputs of the plurality of light receiving areas.