JPS61258185A - End face detecting device - Google Patents

Abstract

PURPOSE:To detect exactly an end face even if a photodetector has a dead zone, by constituting the titled device so that the other is not in a dead zone area, when one of a pair of photodetectors is in the dead zone area with respect to an optical image. CONSTITUTION:In each photodetector 39, 40, photodetecting parts 45-48, 49-52 of four pieces each are formed. The elements 39, 40 are placed so that they do not coincide with each other unless the relative position relation against an optical image 53 is rotated centering around an intersection 54 of a split line to each other. Also, they are used in common for the first optical system for forming the optical image 53 on a photodetecting surface 43 of the element 39, and the second optical system for forming the optical image 53 on a photodetecting surface 44. Adders 60, 61, deciding circuits 64, 65, and AND circuits 66, 67 inhibit its output, when the first end face detecting signal generating circuit 63 cannot detect the end face, and also output a signal from the second end face detecting signal generating circuit 77. Also, adders 74, 75, deciding circuits 78, 79, and AND circuits 80, 81 inhibit its output together with an AND circuit 82, when the circuit 77 cannot detect the end face.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an optical image of an object to be detected at an end face, in which a light receiving surface is defined into four areas by two dividing lines substantially perpendicular to each other. An image is formed on the light-receiving surface of a light-receiving element in which a number of light-receiving parts are formed, and each output from each light-receiving part is added and subtracted to generate an edge detection signal. The present invention relates to an improvement of an end face detection device that detects an end face.

(Prior Art) Conventionally, as shown in FIG. 1, an end face detection device has been equipped with a method in which an object 3 to be detected for an end face is moved so as to cross a parallel beam optical path 2 of an optical system 1 for end face detection. A device in which an optical image is formed on the light-receiving surface 6 of the light-receiving element 5 is known (see Japanese Patent Laid-Open No. 173408/1983). As shown in FIG. 2, the light-receiving surface 6 of the light-receiving element 5 is defined into four areas by two dividing lines 7 and 8 that are substantially perpendicular to each other, and includes four light-receiving sections 9, 10, 11, 12 are formed. Each of the light receiving sections 9.10, 11.12 is connected to an edge detection signal generation circuit 13, and the edge detection signal generation circuit 13 converts each output from each of the light receiving sections 9.10, 11.12 into a subtractor. 14. Addition and subtraction operations are performed according to 15.16, and the third
It is supposed to generate end face detection signals as shown in Figures (A) and (B). In addition, in Figure 1, 17.18
is an illumination light source, 19.20 is a condensing lens, 21 is a half mirror, and 122 is an imaging lens.

(Problems to be Solved by the Invention) By the way, in this conventional end face detection device, as shown in FIG. There is a problem in that the output of the detection signal becomes small and the light receiving element 5 has a dead zone in which the end face cannot be detected.

For example, when the optical image 23 advances toward the light-receiving surface 6 in the direction of the arrow A Light is blocked. Therefore, the output of the light receiving section 9-12 is changed to P, Q,
When R, The outputs P and Q are input to a subtracter 14, and the subtracter 14 outputs the difference P-Q, and the outputs R and X are input to the subtracter 15, and the subtracter 15 outputs the difference R-X. is output, and the outputs P-Q, R-X
is input to the subtracter 16, and from the subtracter 16 (P-Q)
-(R-X) will be output, but if the outputs P and R are approximately equal and the outputs Q and
There is a problem in that the amplitude of the end face detection signal output from the end face detection signal becomes small, and it is virtually impossible to obtain the end face detection signal.

This is also the case when the optical image 23 advances to the light receiving surface 6 from the arrow Bt or CL -01 direction. It has a dead zone where end face detection cannot be performed depending on the approach angle.

Therefore, as shown in FIG.
The end face 3 of the object 3 for end face detection by the sensor 29 having 8
An end face detection device that detects a is known (
(Refer to Japanese Patent Publication No. 52-30866), this sensor 29
The one using the above has the advantage of not having a dead zone compared to the above-mentioned one, but has the following disadvantages compared to the above-mentioned one.

The light-receiving performance of a light-receiving element is proportional to its light-receiving area, so
In making the comparison, each of the light receiving elements 24 to 24 of the sensor 29
It is assumed that the light receiving area Y of 28 is equal to the light receiving area 2 of the light receiving parts 9 to 12 of the light receiving element 5.

At that time, the diameter of the light receiving element 5 is Φ (see FIG. 5).

If the diameter of each of the light receiving elements 24 to 28 of the sensor 29 is φ, the total area S of the light receiving element 5 is S=πΦ2/4, and the area 2 of each of the light receiving parts 9 to 12 is Z=πΦsu16°. Element 24
The area Y of −28 is Y=πφ2/4.

In the case of the sensor 29, the outer edge of each light receiving element 24 to 28 is
As shown in the figure, the accuracy of end face detection will deteriorate unless it is geometrically arranged so as to be in contact with each tangent line.Assuming that it is arranged in this way, it is possible to The center-to-center distance Q between the arranged light receiving elements to the center 02 is calculated as follows: Q1=/7φ. Therefore, from the center 01 to the center line m
The interval 2 between 1 and the tangent line ■8 to the intersection O1 is n=(”'
It becomes zφ+φ12.

Therefore, the maximum spacing 2Q of the light receiving elements arranged on both sides of the central light receiving element 24 is 2M=znφ+φ.

Since φ: Φ12, approximately 2 m = 1.96 Φ, and the detection width I of the end face detection object 3 is, at least in the case of the light receiving element 5, as shown in FIG. It is approximately twice as large. In addition, the minimum detection length @ (see Fig. 5) of the end face detection target object 3 is m in the case of the light receiving element 5.
=o, 5Φ, which is the resolution, but in the case of sensor 29, ts=Q =0.96Φ.

As shown in FIG. 6, in the case of the sensor 29, the overall size is approximately four times larger in both the vertical and horizontal directions, and the accuracy of detecting the end face of the object 3 to be detected is lower than this.

(Objective of the Invention) Therefore, one object of the present invention is to provide an end face detection device that can accurately detect an end face using a four-segment light receiving element even if it has a dead zone.

(Means for Solving the Problems) The configuration of the present invention is such that the light-receiving surface is defined into four areas by two dividing lines that are substantially perpendicular to each other, thereby forming four light-receiving parts, and a pair of light-receiving elements arranged such that their relative positions with respect to the optical image of the object to be detected do not match unless they are rotated about the intersection of the dividing lines; and light-receiving of one of the pair of light-receiving elements. a first optical system having an optical axis passing through the intersection of the dividing lines of the elements, and forming an optical image of the object to be detected at the end face on the light receiving surface of the light receiving element;

a second optical system having an optical axis passing through the intersection of dividing lines of one of the pair of light receiving elements, and forming an optical image of the end face detection target on the light receiving surface of the other light receiving element; a first end face detection signal generation circuit which receives outputs from each light receiving part of the one light receiving element and generates an end face detection signal by performing addition/subtraction operations on each output; and each light receiving part of the other light receiving element. a second end face detection signal generation circuit which receives the outputs from the input terminals and generates an end face detection signal by adding and subtracting each output; Determine which of the generation circuit and the second end face detection signal generation circuit is in a detection signal generation incapable state, and based on the determination result, the first end face detection signal generation circuit and the second end face detection signal generation circuit. A discrimination circuit is provided for outputting an end face detection signal from the end face detection signal which is in a state where the end face detection signal can be generated.

(Function) According to this, when one of the pair of light receiving elements is in the dead zone area with respect to the optical image, the other one is not in the dead zone area, so when a four-segment type light receiving element is used. Even in the case where the end face is detected accurately.

(Example) Examples of the end face detection device according to the present invention will be described below with reference to the drawings.

FIG. 7 shows the optical system 30 of the edge detection device according to the present invention. In FIG. 7, 31.32 is an illumination light source, 33.34 is a condensing lens, 35 is an imaging lens, and 36 is Half mirror 137 indicates a beam splitter,
The beam splitter 37 has a function of distributing and forming an optical image of the end face detection target 38 onto a pair of light receiving elements 39 and 40. The illumination light source 32 and half mirror 36 are provided to slightly illuminate the surface of the target object 38 for end face detection to make it easier to see the overlapping state with the black reticle line using a finder (not shown). This is not necessarily necessary in an end face detection device that does not detect wA using a finder. As shown in FIGS. 8 and 9, the light-receiving surfaces 43,44 of the pair of light-receiving elements 39,40 are defined into four regions by two dividing lines 41,42 that are substantially perpendicular to each other, Each light receiving element 39.40 has four light receiving sections 45-48,49-
52 is formed. This pair of light receiving elements 39.40
are arranged so that the relative positional relationship of the end face detection object 38 with respect to the optical image 53 will not match unless rotated about the intersection 54 of the dividing line. The optical system 30 is
Here, a first optical system having an optical axis 23 passing through the intersection 54 of the dividing line of the light receiving element 39 forms an optical image 53 of the end face detection target 38 on the light receiving surface 43 of the light receiving element 39.

The end face detection object 38 has an optical axis Q passing through the intersection 54 of the dividing line of the light receiving element 40.
It is also used in common with a second optical system that forms an optical image 53.

As shown in FIGS. 8 and 9, the light receiving section 45 includes a subtracter 55
and a subtracter 57, and its output is designated as A.

The light receiving unit 46 is connected to a subtracter 55 and a subtracter 58,
Let the output be B. The light receiving section 47 is connected to a subtracter 56 and a subtracter 57, and its output is C. Smoke section 48
is connected to the subtractor 56 and the subtractor 58, and its output is designated as D. The subtracter 55 outputs an output A-B, and the subtracter 5
6 has a function of outputting an output CD, a subtracter 57 outputs an output A-C, and a subtracter 58 has a function of outputting an output B-D. The output A-8 of the subtracter 55 is sent to the subtracter 59 and the adder 60.
It has been entered. The output CD of the subtracter 56 is input to a subtracter 59 and an adder 60, and the outputs A-C and BD of the subtracters 57 and 58 are input to an adder 61. The subtracter 59 calculates the difference (A-8)- between the output A-B and the output C-D.
It has a function of outputting (CD) to the determination circuit 62 and a pointer control circuit to be described later, and its output is denoted by α. The determination circuit 62 includes a first end face signal generation circuit 63 which receives the outputs of the light receiving sections 45 to 48 of the light receiving element 39 together with a subtracter 59, adds and subtracts the respective outputs, and generates an end face detection signal.
It roughly consists of The adder 60 has an output A-B and an output C-D.
The adder 61 has a function of outputting the sum (A-8) + (C-D) of the output A-C and the output B-D to the determination circuit 64, and the adder 61 outputs the sum (A-C) + of the output A-C and the output B-D. (B-D) judgment circuit 65
It has a function to output towards. Note that the determination circuit 62
．． The functions of 64 and 65 will be described later.The output of the 0 judgment circuit 64 and 65 is input to an AND circuit 66, and the output of the AND circuit 66 is input to an AND circuit 67 and an inverter circuit 68, and is also input to a pointer control circuit. This output is denoted by γ. Adder 60, adder 61, determination circuit 64
．． 65, AND circuits 66 and 67 have a function of inhibiting the output of the first end face detection signal generation circuit 63 when the end face cannot be detected, and cooperate with the inverter circuit 68 to generate a second end face detection signal, which will be described later. It has the function of outputting an edge detection signal from the circuit.

The light receiving section 49 is connected to a subtracter 70 and a subtracter 72, and its output is designated as A. The light receiving section 50 has a subtracter 69 and a subtracter 7.
2, and its output is designated as B. The light receiving section 51 is connected to a subtracter 70 and a subtracter 71, and the output thereof is designated as C. The light receiving section 52 is connected to a subtracter 69 and a subtracter 71, and the output thereof is designated as D. The subtracter 72 has a function of outputting an output A-B, the subtracter 71 outputs an output C-O, the subtracter 70 outputs an output A-C, and the subtracter 69 has a function of outputting an output B-D. . The output A-B of the subtracter 72 is input to a subtracter 73 and an adder 74. Output C- of subtractor 71
D is input to the subtracter 73 and the adder 74, and the subtracter 7
The outputs A-C and B-El of 0.69 are input to an adder 75. The subtracter 73 has an output A-B and an output C-D.
The 0 judgment circuit 76 has a function of outputting the difference (A-B) - (C-D) from It generally constitutes a second end face signal generation circuit 77 which receives the outputs of the light receiving sections 49 to 52 of the light receiving element 40, adds and subtracts the outputs, and generates an end face detection signal. The adder 74 has a function of outputting the sum (A-B)+(c-o) of the output A-B and the output CD to the determination circuit 78.
5 is the sum of output A-C and output B-D (A-C) + (B
-D) to the determination circuit 79. The outputs of the determination circuits 78 and 79 are input to an AND circuit 80, and the output of the AND circuit 80 is input to an AND circuit 81 together with the output of the inverter circuit 68. The output of the AND circuit 81 is combined with the output of the 1 judgment circuit 76 and the AND circuit 8
2, and outputs an output δ toward the pointer control circuit. Adder 74.75, determination circuit 78.79. The AND circuits 80 and 81 have a function of inhibiting the output of the second end face detection signal generating circuit 77 together with the AND circuit 82 when the end face cannot be detected.

When the optical image 53 advances toward the light receiving element 39, 40 from the direction of arrow A in the posture shown in FIG. The waveform becomes as shown in FIG. 10, and the light receiving element 4
The waveforms of the outputs A-D of the respective light receiving sections 49 to 52 of 0 are as shown in FIG.

First, in the light receiving element 39, the end #53a of the optical image 53 approaches the light receiving section 45.47, and the outputs A and C of the light receiving section 45.47 begin to decrease (time t1).
The manner in which C decreases is approximately the same when the light receiving sections 45 and 47 are symmetrically shielded from light, but when the attitude of the optical image 53 with respect to the light receiving element 39 is somewhat tilted, this output A decreases.
, C will begin to decrease first. Next, when the edge 53a touches the intersection 54, the light receiving portion 45.4
7's outputs A and C become zero (time tz). After that, the edge 53a approaches the light receiving section 46.48, so the outputs B and D of the light receiving section 46.48 begin to decrease.
When the light receiving sections 46 and 48 are completely covered by the optical image 53, their outputs B and D become zero (time ti). The manner in which the outputs B and D of the light receiving sections 46 and 48 are decreased also depends on the light receiving section 46.
．． 48 are symmetrically shielded from light, so they are almost the same.

On the other hand, in the light receiving element 40, the edge 53a of the optical image 53 first touches the light receiving section 51, and the output C of the light receiving section 51 begins to decrease (time ◯). After a while, the light receiving sections 49 and 52 begin to be blocked by the optical image 43.

Therefore, after the output C of the light receiving section 51 starts to decrease and before the output C becomes zero, the outputs A and D of the light receiving section 49.52
begins to decrease. When the edge 53a of the optical image 53 reaches the intersection 54, the output C of the light receiving section 51 becomes zero (at time tz
). At this time, approximately half of the light receiving sections 49 and 52 are shielded from light, so the outputs A and D thereof become approximately half of the initial values. Thereafter, the light receiving section 50 begins to be shielded from light and its output B begins to decrease, and before the output B reaches zero, the light receiving section 4
9.52 is completely blocked and its output A.

D becomes zero (time ta). Note that since the light receiving sections 49 and 52 are symmetrically shielded from light, their outputs A and D
The method of decrease is also roughly the same.

The outputs of the subtractors 55-58 are as shown in FIG. 11, and the outputs of the subtracters 69-72 are as shown in FIG. 15. That is, the light receiving element 39 outputs A,
Since C decreases almost equally and outputs B and D decrease almost equally, the outputs of subtractors 57 and 58 become approximately zero, and subtractor 5
5.56 outputs A-8 and CD have substantially the same waveforms with constant amplitude. Therefore, this output A-B, C-
The output (A-8) of the subtracter 59 which subtracts and outputs the
The waveform of CD) becomes approximately zero as shown in FIG.

Also, an adder 6 that adds and outputs outputs A-C and B-D.
The waveform of the output (A-C)+(B-D) of 1 also becomes approximately zero. On the contrary.

Adder 6 that adds output A-B and output CD and outputs the result
The output (A-8) + (C-D) of ° is the output A-B,
It becomes a negative waveform with approximately twice the amplitude of CD. The determination circuit 64.65 determines whether the output of the adder 60.61 exceeds the reference amplitude value by 1, and becomes H if it exceeds the reference amplitude value Ki. The output of the determination circuit 64 is connected to an adder 6.
Since the output of 0 exceeds the reference amplitude value, it becomes H as shown in FIG. 13, but the output N of the judgment circuit 65 indicates that the output of the adder 61 does not exceed the reference amplitude value So L
bawl.

The output F of the determination circuit 62 becomes H when the amplitude of the output of the subtracter 59 is less than or equal to the reference amplitude value. Here, since the output of the subtracter 59 is near zero, the output maintains H. The AND circuit 66 determines that the output of the determination circuit 64 is H.
Since the output of the 1 determination circuit 65 is already output, the output becomes L. Therefore, the output of the AND circuit 67 becomes L, and the end face detection signal is not output from the end face detection signal generation circuit 63, and output is prohibited. Note that the magnitude of the reference amplitude value and the reference amplitude value can be adjusted.

The waveforms of the outputs of the subtracters 69-72 are as shown in FIG. That is, the output of the subtracter 69 is the output B
Since the output A decreases first before the output A begins to decrease, the waveform has a positive amplitude on the time t3 side as shown in FIG. Since the output C becomes zero when the value decreases, it becomes a positive waveform that is symmetrical with respect to time t2, and the output of the subtracter 71 becomes a negative waveform that is symmetrical to the waveform of the output of the subtracter 70. .

Since the output A of the subtractor 72 decreases to approximately half of its initial value before the output B begins to decrease, the output of the subtracter 72 is at time t3.
The waveform has a negative amplitude on the side, and is symmetrical to the output of the subtracter 69. Therefore, the output (A-C) + (B-D) output from the adder 74 becomes a positive waveform exceeding the reference amplitude value □ as shown in FIG.
The output (A-B) + (C-D) output from the first
As shown in Fig. 6, the reference amplitude value becomes a negative waveform exceeding 1, and the output (A-B)-(C-
D) is a pseudo sine wave whose reference amplitude value has a part exceeding 2 as shown in FIG. The output F of the determination circuit 76 accordingly changes from H to L, becomes H near time t2, becomes L again, and then becomes H. The AND circuit 80 is the judgment circuit 78.79
becomes H when is H, and since the output ■ is input to the AND circuit 81 via the inverter circuit 68, it outputs H near time t2. Therefore, the second end face detection signal generation circuit 77 detects the end face. A signal ε will be output.

This end face detection signal ε is input to the pointer control circuit.

When the optical image 53 advances toward the light receiving element 39, 40 from the arrow A1 direction in the posture shown in FIG. is as shown in FIG. 18, and the light receiving element 4
The waveforms of the outputs A-D of each of the light receiving sections 49 to 52 of 0 are as shown in FIG.

First, in the light receiving element 40, the edge 53a of the optical image 53 approaches the light receiving section 49.51, and the outputs A and C of the light receiving section 49.51 begin to decrease (time t□). This output A, C
The manner in which the output A decreases is approximately the same when the light receiving sections 49 and 51 are symmetrically shielded from light, but when the attitude of the optical image 53 with respect to the light receiving element 40 is somewhat inclined, the output A,
One of C will start decreasing first. Next, when the edge 53a touches the intersection 54, the light receiving portion 49.51
The outputs A and C become zero (time t2). After that, the edge 53a approaches the light receiving section 50.52, so the outputs B and D of the light receiving section 50.52 begin to decrease, and when the light receiving section 50.52 is completely covered by the optical image 53, the Outputs B and D become zero (time t). The manner in which the outputs B and D of the light receiving portions 50 and 52 decrease is also determined by the light receiving portions 50 and 52.
52 are symmetrically shielded from light, so they are almost the same.

On the other hand, in the light receiving element 39, the edge 53a of the optical image 53 first hits the light receiving section 45, and the output A of the light receiving section 45 begins to decrease (time t). After a while, the light receiving sections 46 and 47 begin to be blocked by the optical image 53.

Therefore, after the output A of the light receiving section 45 starts to decrease and before the output A becomes zero, the outputs B and C of the light receiving section 46 and 47 will decrease.
begins to decrease. When the edge 53a of the optical image 53 approaches the intersection 54, the output A of the light receiving section 45 becomes zero (at time tz
). At this time, approximately half of the light receiving sections 46 and 47 are shielded from light, so the outputs B and C thereof become approximately half of the initial values. After that, the light receiving section 48 begins to be shielded from light and its output begins to decrease, and before the output reaches zero, the light receiving section 4
6.47 is completely shielded from light, and its outputs B and C become zero (time ti). Note that since the light receiving sections 46 and 47 are symmetrically shielded from light, the manner in which their outputs B and C are reduced is also approximately the same.

The outputs of the subtractors 55-58 are as shown in FIG. 19, and the outputs of the subtractors 69-72 are as shown in FIG. 23. That is, in the light receiving element 40, the output A,
Since C decreases almost equally and the outputs B and D decrease almost equally, the outputs A-C and B-D of the subtractor 69.70 become approximately zero, and the output A- of the subtractor 71.72 becomes approximately zero. 8, C-D are approximately the same negative waveforms with constant amplitude. Therefore, the waveform of the output (A-8)-(C-D) of the subtracter 73, which subtracts and outputs the outputs A-B and CD, becomes approximately zero as shown in FIG. . Also, the output (A-C) + (B-D) of the adder 75 that adds and outputs the outputs A-C and B-D.
The waveform of is also approximately zero. On the other hand, the output of the adder 74 (A-8
)+(C-D) will output a negative waveform having approximately twice the amplitude of the outputs A-B and C-D. Judgment circuit 7
8.79 determines whether the output of the adder 74.75 exceeds the reference amplitude value by 1, and becomes H when the reference amplitude exceeds the value. The output H of the determination circuit 78 is sent to the adder 74.
Since the output of the adder 75 exceeds the reference amplitude value, it becomes H as shown in FIG. bawl.

The output of the determination circuit 76 becomes H when the amplitude of the output of the subtracter 73 is less than or equal to the reference amplitude value. Here, since the output of the subtracter 73 is near zero, its output F maintains H. The AND circuit 80 determines that the output of the determination circuit 78 is H.
Since the output of the 1 determination circuit 79 is L, the output becomes L. Therefore, the output of the AND circuit 81 becomes L, and the output of the AND circuit 82 becomes L.

The edge detection signal will not be output from the edge detection signal generation circuit 77, and output will be prohibited.

The waveforms of the outputs of the subtracters 55 to 58 are as shown in FIG. That is, the output of the subtracter 55 is the output B
Since the output A becomes zero when the
As shown in Fig. 9, the waveform has a negative amplitude at time t, and the output of the subtracter 56 starts to decrease when the output C decreases by about half, so the output C starts decreasing at time t0. The output of the subtracter 57 has a negative amplitude that is substantially the same as the output of the subtracter 55. Subtractor 5
The output of the subtracter 56 has a negative waveform that is substantially the same as the output of the subtracter 56 because the output starts to decrease when the output B starts to decrease by about half. Therefore, the output (A-C) + (B-D) output from the adder 61 becomes a negative waveform exceeding the reference amplitude value as shown in FIG.
As shown in FIG. )−(c
-o) becomes a pseudo sine wave having a portion exceeding 2 in the reference amplitude value as shown in FIG. The outputs M and N of the determination circuits 64 and 65 accordingly become H as shown in FIG. 21, and the output F of the determination circuit 62 accordingly changes from H to L.
Then, it becomes H near time t2, becomes L again, and then becomes H. The AND circuit 66 is connected to the determination circuit 64.
When 65 is H, it becomes H, and the output 1 of the AND circuit 66 is inverted and inputted via the inverter circuit 68.
The output of AND circuit 8 is prohibited, and AND circuit 6
Since the output H of the AND circuit 66 is input to 7, the AND circuit 67 outputs H near time t2, and the first edge detection signal generation circuit 63 outputs the edge detection signal ε.

The four-division shape of the light-receiving elements 39 and 40 is not limited to a quadruple shape, but also a square shape divided into small squares as shown in Fig. 26, and a square shape as shown in Fig. 27. The light-receiving elements 39 and 40 may be divided into four isosceles triangles, or any other shape having an arbitrary outer shape may be divided into four equal parts.

Further, this end face detection device can be applied to a projection device 83, a tool microscope 84, a belt conveyor type conveyance device 85, and other arbitrary devices as shown in FIGS. 28 to 30.

Next, the pointer control circuit will be explained with reference to FIGS. 31 to 35.

In this FIG. 31, 86 is a pointer control circuit.

This pointer control circuit 86 includes a meter 87 and a red indicator light 8.
9, green indicator light 88, relay 90.91.93,
It has an OR circuit 92. The reason why the red indicator light 89 and the green indicator light 88 are provided outside the pointer 87a is as follows.

The pointer control circuit 86 detects the end face 38a of the end face detection target object 38.
The pointer 87a is configured to display "O" when the optical image 53 is detected.
〜52 is covered (see Figure 32), r
QJ, and when the edge 53a of the optical image 53 is between ■ and ■, there is a slight deflection as shown in FIG. 33 (c), and when it is between ■ and As shown in (d), as the edge 53a of the optical image 53 moves from ■ to ■, it swings toward the vicinity of "0" as shown in FIG. Intersection 54
The deflection of the pointer when passing through becomes rQJ. Then, as the edge 53a of the optical image 53 moves toward the position ■, the pointer 87a swings slightly to the opposite side as shown in FIG. As the pointer 87a moves toward the position (2), the deflection increases as shown in (f) in Fig. 35, and as it passes through the point (2) and moves toward the position (2), the deflection of the pointer 87a increases as shown in (f) in Fig. 5. ), it gradually decreases, and when it passes through the position of ■, it becomes "0".

Therefore, when the end face is detected and when the end face is slightly approaching the light-receiving element, the pointer 87a ends up pointing near “0”, making it difficult to confirm when the end face is being detected, so the red display A light 89 and a green indicator light 88 are provided.

Relay 90 is composed of fixed contacts 94,95 and movable contacts 96, relay 91 is composed of fixed contacts 97,98 and movable contacts 99, and relay 93 is composed of fixed contacts 94,95 and movable contacts 96.
0.101 and a movable contact 102. The fixed contact 94 is connected to the subtracter 55, and the movable contact 96 is closed when the output γ of the AND circuit 66 is H. The fixed contact 97 is connected to the subtracter 72, and the movable contact 99 is closed when the output δ of the AND circuit 81 is H. The fixed contact 100 is connected to an OR circuit 92, and the OR circuit 92 is connected to an AND circuit 66.81.
The movable contact 102 is connected to the AND circuit 67.
When the output E of 82 is 11, it is closed.

The fixed contacts 100 and 101 are connected via a resistor 103, the red indicator light 89 is connected to the fixed contact 101 and the resistor 103, and the green indicator light 88 is connected to the OR circuit 92 via an inverter circuit 104. .

Next, the operation of this pointer control circuit will be explained.

Here, a case will be described in which the light receiving elements 39 and 40 are in a relative relationship as shown in FIG. 8 with respect to the optical image 53.

When the edge 53a of the optical image 53 is in front of the position shown by ■ in FIG. As shown in FIG. 15, it is zero (before time t□). then.

The output γ of the AND circuit 66 and the output δ of the AND circuit 81 are both L, so the OR circuit 92 is output, and the output of the inverter circuit 104 is H, so the red indicator light 89 lights up. are doing. The optical image 53 is shown as ■ in FIG.
Similarly, when the light receiving surface 44 is completely covered, the red indicator light 89 is lit (
time t, onwards). The output γ of the AND circuit 66 is the optical image 53
remains zero even if it covers the light-receiving surface 43, but the output δ of the AND circuit 8I becomes 11 when the outputs M and N of the judgment circuit 78 and 79 are H (from ■ to ■ in Fig. 32). ). Furthermore, when the output δ of the AND circuit 81 becomes H, the relay 91
The movable contact 99 is closed and the pointer 87a begins to swing. The deflection of this pointer 87a is approximately at its maximum at the position marked with ■ in FIG. 32. At the same time, when the output δ of the AND circuit 81 becomes H, the green indicator light 88 is weakly activated via the resistor 103 (between ■ and ■ and between ■ and ■ in FIG. 32). Then, near time t2, the movable contact 102 of the relay 93 is closed by the output ε, and the green indicator light 88 is turned on. From then on, the lights will turn on and off repeatedly in the reverse order, so a detailed explanation will be omitted.

I will use a table to summarize.

···············table·········
・・・・・・Position ■ ■ ■ ■ ■ ■ ■ Red Lights on Lights off Lights off Lights off Lights on Lights off Lights off Lights out Light hit Strong light Lights out Lights out Time...tl... t2
・・・・・・t、・・・・・・Pointer position (c)(d)
(E) (F) (G) Standard value K□ or less...K1
Above...K1 or above...K□ or below...within 2, outside 2, outside 8, inside 2, outside 2, inside l According to this, when detecting the end face, the 33rd Since the green indicator light 88 hits strongly at the position indicated by ■ in the figure, it is possible to easily confirm the end face detection by distinguishing it from the case where the end face is slightly overlapping the light receiving element.

(Effects of the Invention) As explained above, the present invention provides that when one of a pair of light receiving elements is in a dead zone region with respect to an optical image, the other light receiving element is not sensitive to an optical image. Since the light receiving element is configured so as not to be in a dead zone, even if the light receiving element has a dead zone, it is possible to accurately detect the end face. Further, even if the object to be detected has a small length and width, it can be detected, and the detection accuracy is higher than that of an object having five light-receiving elements.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an optical system of a conventional edge detection device, and FIG. 2 is a configuration diagram of its edge detection signal generation circuit. Figures 3(a) and 3(b) are waveform diagrams of the edge detection signal, Figures 4 to 6 are explanatory diagrams for explaining the problems of the conventional edge detection device, and Figure 7 is the invention of the present invention. FIGS. 8 and 9 are configuration diagrams of the edge detection signal generation circuit, and FIGS. 10 to 25 are explanatory waveform diagrams of the edge detection signal of the edge detection signal generation circuit. FIGS. 26 and 27 are diagrams showing other examples of light receiving elements used in the end face detection device, and FIGS. 28 to 30 are diagrams for explaining application examples of the end face detection device according to the present invention. 31 is a diagram of the pointer control circuit according to the present invention, and FIG. 32-
FIG. 35 is an explanatory diagram of the pointer control circuit. 30... Optical system 38... End face detection target object 38
a... End surface 39.40... Light receiving elements 45 to 52
... Light receiving part 2 Q, ... Optical axis 53 ... Optical image
53a... Edges 55-59... Subtractor 62.64.65... Judgment circuit 63... First end face detection signal generation circuit 69-73... Subtractor 76.78.79...・Judgment circuit 77...Second end face detection signal generation circuit )-(C-D) Figure 22 Figure 23 Figure 24 Figure 25 t+ tz t3St 'ET2 13 Figure 26 Figure 27 48.52 Figure 29 Procedural amendment (method) August 21, 1985

Claims (1)

[Claims] (1) The light-receiving surface is defined into four areas by two dividing lines that are substantially orthogonal to each other, forming four light-receiving parts, and the relative positional relationship with respect to the optical image of the end face detection target is as follows. A pair of light-receiving elements arranged so that they do not align unless rotated around the intersection of the dividing lines, and an optical axis passing through the intersection of the dividing lines of one of the pair of light-receiving elements. , a first optical system that forms an optical image of the object to be detected at the end face on the light-receiving surface of the light-receiving element, and an optical axis passing through the intersection of the dividing line of the other of the pair of light-receiving elements. , a second optical system that forms an optical image of the object to be detected at the end face on the light receiving surface of the other light receiving element; and outputs from each light receiving section of the one light receiving element are inputted, and each output is added and subtracted. a first end face detection signal generation circuit that generates an end face detection signal using the input signal; and a second end face detection circuit that receives the outputs from each light receiving section of the other light receiving element and generates an end face detection signal by adding and subtracting each output. a signal generating circuit; and determining whether either the first end face detection signal generating circuit or the second end face detecting signal generating circuit is in a detection signal generation incapable state based on the output of each light receiving section of the pair of light receiving elements. a discrimination circuit that outputs an edge detection signal from one of the first edge detection signal generation circuit and the second edge detection signal generation circuit that is in a state capable of generating an edge detection signal based on the discrimination result; An end face detection device characterized by: