JPH05302818A - Object shape detector - Google Patents

Abstract

PURPOSE:To enable ensuring quick responsibility and detecting the correct object position even in the case light points cover a plurality of output points, by separating a semiconductor position detector element into a plurality and making each separation region output the detection signals. CONSTITUTION:For a detection circuit 11, a plurality (n) of separation regions are provided in a semiconductor position detector element and output points T0 to Tn are provided for each separation region. For each output signal from the output points T0 to Tn, a current to voltage converter amplifiers A0 to An are provided and the outputs V0 to Vn from the amplifiers A0 to An are input to a judgment circuit 12 for judging rough incident position of light. Also, a switching circuit 13 to switch among outputs V0 to Vn to be sent with selection signal from the judgment circuit 12 is provided. And the output from the switching circuit 13 is sent to an arithmetic circuit 14, the light incidence position is calculated and the detailed position output D is output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical object shape detecting device for measuring the shape of an object in a non-contact manner.

[0002]

2. Description of the Related Art Generally, an optical object shape detecting device used in an inspection device such as a visual inspection device for a printed circuit board is designed to detect the position of a light spot formed by irradiating the inspection surface of a target object with light. Is used to detect the shape, and generally, a configuration in which the shape of the target object is measured by the triangulation method as shown in FIG. 1 is widely used. That is, the laser light L from the laser light source 1 is narrowed down by the lens 2, scanned by the galvanometer mirror 4 that vibrates by the drive of the motor 3, and is irradiated onto the target object 6 on the stage 5. Then, the reflected light from the target object 6 is reflected by the galvanometer mirror 4, and then is condensed by the imaging lens 7 to form an image on the incident position detection element 8 of the light. Then, the stage 5 is allowed to freely move in both of the two orthogonal horizontal X and Y directions so that the laser light L can be irradiated to any portion visible from the upper portion of the target object 6. ..

The object shape detecting device having the configuration shown in FIG. 1 is an example, and as a modification, another galvanometer mirror is used.
Individually installed so as to be orthogonal to each other so that the stage can be horizontally scanned at an arbitrary high speed, or only the stage can be moved without the galvano mirror. In some cases, the target object 6 is basically irradiated with the irradiation light L as shown in FIG. 2, and the reflected light is condensed by the imaging lens 7 to be moved. An image is formed on the incident position detection element 8, and position detection is performed based on the triangulation method utilizing the fact that the image formation point in this case changes according to the height of the target object 6.

In such a general object shape detecting device, a resistance layer is formed on the photoelectric layer as the light incident position detecting element 8, and a photocurrent generated at the light incident portion on the photoelectric layer is generated. By calculating the output current from each output electrode using the property that can be detected by each output electrode according to the resistance value of the resistance layer between each output electrode formed on the resistance layer and the light incident position. A so-called semiconductor position detecting element (PSD) that calculates the incident position of light is widely used.

FIG. 9 shows a cross-sectional structure of a semiconductor position detecting element PSD which has been widely used in the past. When light L is incident, photoelectrons are generated in the photoelectric layer P and pass through the resistance layer R to output electrode Ta. And Tb, and the output current I
a and Ib are detected. The Cb terminal is bias.

Therefore, the output currents Ia and Ib have a value obtained by dividing the photocurrent according to the resistance ratio of the resistance layer R between the light incident position and the output electrodes Ta and Tb, and the resistance of the resistance layer R is uniform. Then, the difference between the output currents (Ia-Ib) divided by the sum of the output currents (Ia + Ib) is the output electrode Ta.
And the distance X from the center position of Tb are used, the following equation 1 is used. Here, the total length is D.

[0007]

[Equation 1] Therefore, the light incident position X is obtained.

Therefore, the output currents Ia and Ib are input to the signal arithmetic circuit shown in FIG.
2 is temporarily amplified, and the operational amplifiers A1 and A2 and the divider DIV are used to calculate (Ia-Ib) / (Ia +) in the equation (1).
Ib) is calculated, and this value is converted into a digital value by the analog-digital converter A / D, whereby the light incident position Xd is obtained.

In recent years, in order to realize a wide detection range and high resolution, as shown in FIG. 11, between the output terminals T0 and Tn at both ends of the semiconductor position detecting element PSD, output terminals T1 and T2, , Tn-1 are provided, or a plurality of semiconductor position detecting elements PSD1, PSD2, ... Are arranged adjacent to each other as shown in FIG.
A configuration having the same effect as that of No. 1 has been proposed.

Therefore, in the case of the semiconductor position detecting element having the structure shown in FIG. 11, first, output terminals at both ends, for example, Ti and Ti + 1 are provided.
The switches Sai and Sbi + 1 corresponding to are selected by closing them, and the position between the two points is calculated by applying it to the above equation 1 to measure the light incident position. That is, the output current I of FIG.
The measurement is performed by connecting a and Ib to the conventional signal arithmetic circuit of FIG. By doing this, the PSD
If N is divided into N sections, if the resolution of one section of PSD is the same as that of the conventional PSD in FIG. 9, then N times accuracy can be expected.

[0011]

However, such a conventional object shape detecting device has the following problems. That is, when the optical power received by the PSD and the required bandwidth are the same, the larger the resistance, the smaller the thermal noise and the better the resolution of the PSD. Therefore, in order to make the resolution of one section of a PSD with N sections the same as that of a normal PSD without sections, it is necessary to make the resistance of one section the same as that of one PSD without sections. There is. That is, a PSD having N sections as a whole has N times the resistance value. On the other hand, the response speed of PSD is
It depends on the time constant determined by the capacity and resistance of the.
Therefore, when first determining the position of the light spot, the output terminal T
When selecting a or Tb and measuring it, P
Compared to SD, PSD having N sections has a very slow response characteristic. For example, in the case of inspecting a printed circuit board, if a 300 × 300 mm printed circuit board is inspected in steps of 30 μm, it is necessary to measure 1 × 10 ⁸ points, and even if a measurement speed of 1 M points / second is 100. Seconds are required, and improvement in high speed is required. As described above, the first problem of the conventional object shape detecting device is that P
The response was poor when high resolution was sought with SD as N divisions.

A second problem of the conventional object shape detecting apparatus is that if the number of sections is increased in order to improve the resolution, as shown in FIG. 13, between two adjacent light points, for example Ti and Ti + 1. Multiple output points, such as Ti-1,
A current is generated from Ti and Ti + 1, and a simple 2
The error was large only by measuring the current between the points. In such a case, it is conceivable to thin out the current at the intermediate point Ti and measure at both ends Ti-1 and Ti + 1. However, the above-mentioned first problem is that the speed is lowered and However, there was a problem that the resolution was also reduced.

A third problem is that the light reflected by the target object may be reflected by another object or another part of the target object and then condensed on the PSD. This was the point where erroneous measurements occurred. That is, as shown in FIG. 14, the incident light L strikes the target object 6 at the point A, and a part of the reflected light is diffused light and the incident position detection element 8 of the light is detected.
Is condensed by the condensing lens 7 to the PSD Pa point, and another part of the reflected light irradiates the B point of the target object 6, and the light from the B point is collected at the PSD Pb point. Light lens 7
May be condensed by. Then, in such a case, as shown in FIG. 15, light peaks are created at two points Pa and Pb on the PSD. Therefore, the output terminals T at both ends of the PSD
When a and Tb are selected and the light spot position is calculated as one PSD, the light barycentric position is Pc, and the true position may not always be indicated. Therefore, P of N division
Even with SD, there are cases where the detailed division is not correctly determined and the accurate position cannot be determined.
A measure for eliminating light at the point Pb, which is unnecessary light for SD, is required.

The present invention has been made in view of the above-mentioned conventional problems. In an object shape detecting device using a position detecting element having a large number of outputs, the object shape detecting device has a high-speed response and a light spot It is an object of the present invention to provide an object shape detecting device capable of correctly detecting the position of an object even when covering a plurality of output points and capable of accurately detecting the position even when there are multiple reflections.

[0015]

SUMMARY OF THE INVENTION According to the present invention, light generated from a light source is focused and applied to an object, reflected light from the surface of a target object is imaged and received, and an electric signal is received according to the position of the received light. In the object shape detection device for outputting, a semiconductor position detection element is divided into a plurality of parts, and a detection part for outputting a detection signal from each division and a plurality of outputs from the plurality of divisions of the detection part are simultaneously input. Then, a determination unit that determines an output point indicating an approximate position of the target object, a switching unit that selects and switches the approximate position of the target object determined by the determination unit and a plurality of output point signals adjacent thereto. And a calculation unit for calculating a detailed position from the signal of the output point selected by the switching unit.

Further, the object shape detecting apparatus of the present invention uses, instead of the above-mentioned detecting section, a plurality of semiconductor position detecting elements arranged one-dimensionally adjacent to each other. It is possible to simultaneously input a plurality of outputs of the above to the determination unit.

[0017]

In the object shape detecting apparatus of the present invention, the semiconductor position detecting element is divided into a plurality of parts, and the detecting part arranged to output from each divided section, or the detecting part in which a plurality of semiconductor position detecting elements are one-dimensionally arranged, Depending on the light receiving position of the reflected light from the surface of the object, the semiconductor position detecting element outputs a plurality of outputs from a plurality of divided sections of the corresponding position, or a plurality of semiconductor position detecting elements of the corresponding position, and outputs the determination section simultaneously. input.

The determination section determines an output point indicating an approximate position of the target object with respect to a plurality of inputs from the plurality of divided sections or a plurality of inputs from the plurality of semiconductor position detecting elements, and the switching section determines the output point. , Selecting and switching between the approximate position of the target object determined by this determination unit and the signals of a plurality of output points adjacent thereto, and based on the signals of the output points selected by this switching unit, the calculation unit details the target object. Calculate the position.

Thus, first, the approximate position of the target object is specified, and the position adjacent to the approximate position is referred to by referring to the output of the divided section of the semiconductor position detecting device or the output of the plurality of semiconductor position detecting devices. Determine the detailed position of the object.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 3 is a circuit diagram of an embodiment of the present invention, which is a semiconductor constituting the light incident position detecting element 8 in the arrangement shown in FIGS. 1 and 2 which is a general hardware configuration as an object shape detecting device. 1 shows the configuration of a circuit that performs signal processing on the output of a position detection element (PSD).

As shown in FIG. 3, a detection circuit 11 corresponding to the light incident position detection element 8 in FIGS. 1 and 2.
As one PSD, a plurality of n divided sections are provided, and output points T0 to Tn are provided in each divided section. Current-voltage conversion amplifiers A0 to An for output signals of these output points T0 to Tn are used. Are provided, and the outputs V0 to Vn from these amplifiers A0 to An are input to the determination circuit 12 which determines the approximate position of the incident position of light. Further, a switching circuit 13 is provided for switching which of the outputs V0 to Vn is to be output according to the selection signal from the judging circuit 12, and further, based on the output from this switching circuit 13, the detailed position of the incident position of the light is determined. An arithmetic circuit 14 for calculating is provided, and the arithmetic circuit 1
The detailed position output D0 of the incident position of the light is output from 4.

In the object position detecting device having the above structure, the output currents Ii, Ii, etc. are output from the output terminals Ti, Ti + 1, Ti-1 and the like in the vicinity thereof according to the position of the reflected light L entering the detection circuit 11.
Ii-1 and Ii + 1 are output, which are converted into voltages by the corresponding portions of the current-voltage conversion amplifiers A0 to An and amplified, and are output as output voltages Vi, Vi-1, Vi + 1, etc. 12 and the switching circuit 13.

The judgment circuit 12 judges the approximate position of the incident position of the light, determines the output point indicating the center position of the incident light, and outputs the judgment result D1 to the switching circuit 13.

In the switching circuit 13, the output point D1 indicating the center position from the determination circuit 12 and several output points adjacent to it, for example, voltage inputs Vi-2, Vi-1, Vi from five points.
, Vi + 1, Vi + 2, etc. are selected and output as U-2, U-
It is output as 1, U0, U1, and U2 and input to the arithmetic circuit 14.

In the arithmetic circuit 14, these inputs U-2, U
The detailed position D0 is calculated based on an arithmetic expression to be described later with respect to -1, U0, U1 and U2 and output.

An example of the method of determining the approximate center position in the determining circuit 12 is as follows: Input voltage signals V0 to V
The signal showing the maximum value of n is detected and set as the output point D1. Further, in the switching circuit 13, if the decision circuit 12 selects the signal Vi as the center position D1, this signal Vi and its adjacent signals Vi-2, Vi-1, Vi + 1, Vi +.
5 points of 2 or signal Vi and adjacent to it Vi-1,
Three points of Vi + 1 or other number of signals can be selected, but here, five points are selected.

Then, with respect to the signals U-2, U-1, U0, U1 and U2 at the five points selected by the switching circuit 13, the arithmetic circuit 14 calculates the detailed position based on the following equation. As the calculation method, there are a method of obtaining the position of the center of gravity by weighted average, a method of approximating a function and obtaining the center position of the approximated function, and the method of weighted average is used here.

Therefore, the incident position D of the light on the detection circuit 11 is

[Equation 2] Is.

Here, d is the interval between the output points, and D1
Is the position of the output point which is the center point, and is obtained by the determination circuit 12.

Then, in the arithmetic circuit 14, the second equation of the equation 2 is used.
The term D0 is calculated by the following equation (3).

[0032]

[Equation 3] Here, if the spread of the light spots can be measured sufficiently even at three adjacent points,

[Equation 4] It is also possible to obtain D0.

FIG. 4 shows a detailed circuit configuration of the judgment circuit 12 described above. Now, one semiconductor position detection element PS
If D is divided into 7 and has 8 output terminals,
Eight inputs V0 to V7 are applied to the decision circuit 12 and the switching circuit 13.

Therefore, the decision circuit 12 outputs these signals V0.
To V7, the comparators 15a, 15b,
15c are provided, respectively (V0, V1, V2, V3);
(V4, V5, V6, V7), (V0, V1, V4, V
5); (V2, V3, V6, V7), (V0, V2, V
4, V6); (V1, V3, V5, V7) are divided into input groups and connected to the negative and positive terminals of the comparators 15a, 15b, 15c respectively, and the respective outputs are D
The configuration is 12, D11, and D10. The diode 16
Is for obtaining the maximum value in each input group. With this configuration, the maximum voltage is searched from the input signals V0 to V7, and the searched point is set to 2
It is 2 ^{2 for} D12, 2 ^{1 for} D11 and 2 ^{0 for} D10 according to the base number.
Will be shown.

Therefore, in order to obtain D12, V7 to V4
The maximum value of V3 and the maximum value of V3 to V0.
, And the maximum value becomes the output T7 to T4 or T3 to T0
Decide what to do. Similarly, D11 determines the maximum value of V7, V6, V3, V2 where 2 ¹ is true and the maximum value of V5, V4, V1, V0 which is false in order to determine 2 ^1.
Compare by b. And D10 in order to determine the 2 ^0, and odd outputs of V7, V5, V3, V1, V6, V4
, V2, V0, whichever has the maximum value, the comparator 15c compares the maximum value of the odd output with the maximum value of the even output.

By the above, the maximum value is output terminals T7 to T0.
It is possible to determine which of D12, D11,
D10 is combined and output as a D1 signal, and is also supplied to the switching circuit 13 to be used as a switching signal.

The switching circuit 13 can be configured as shown in FIG. The switching circuit 13 of FIG. 5 has inputs V0 to V7.
Is a circuit for determining three signals U-1, U0, U1 by switching eight of the above, and outputs D12, D11, D from the decision circuit 12.
The input signal D12, D1 is composed of a decoder 17 which receives 10 and an analog switch circuit 18.
1, D10 are decoded by the decoder 17 and output U-
It is used as a selection signal of a switch circuit 18 which selects one signal for each of U1, U0, and outputs U-1, U0.
, U1 are to be taken out. At present, with the progress of integration, an analog switch circuit for selecting one signal from eight analog signals is provided by one IC, and the circuit shown in FIG. 5 can be easily realized. ..

Therefore, assuming that the output T4 is selected, "4" becomes true by the decoder 17, and U-1, U
The analog switch circuit 18 is closed so as to select V3, V4, and V5 for 0 and U1. That is, the central value V4
And V3 and V5 adjacent to this are selected.

The outputs U-1, U0 selected in this way
, U1 signals are input to the arithmetic circuit 14, where detailed position calculation is executed. FIG. 6 shows a circuit configuration for realizing the above-described equation (4). Two arithmetic units 19 and 20 and a divider 21 that divides the inputs of these arithmetic units 19 and 20 are shown.
And an A / D converter 22.

In the arithmetic circuit 14, the arithmetic unit 19
(U ₁ −U ₋₁ ) is calculated by the arithmetic unit 20 and (U ₁ + U ₀ + U ₋₁ ) is calculated by the arithmetic unit 20. As a result, the divider 21 calculates (U ₁ −U ₋₁ ) / (U ₁ + U ₀ + U _-1 ) is calculated and digitally converted by the A / D converter 22 to output the signal D 0. In this case, D0 is a positive or negative number, so if necessary, the value of D1 is -1.
However, D1 and D0 can be combined to show a digital value in a binary number.

As another specific configuration of the arithmetic circuit 14, the circuit configuration shown in FIG. 7 may be used. This Figure 7
Is an example of a circuit that executes the equation (3) with the above-mentioned five signals, and the signals of U-2, U-1, U0, U1, and U2 are A / D.
The converters A / D1 to A / D5 are respectively A / D converted, and the subtracters 23 and 24 and the adders 25 to 28 for adding / subtracting the obtained digital signal to correspond to the equation 3 are provided. A doubling circuit 2 for doubling the output of the subtractor 23
9, an adder 30 of the output of the subtractor 24 and the output of the doubling circuit 29, and a digital division for executing the division of the output of the adder 30 that is the numerator output and the output of the adder 28 that is the denominator output It is composed of a container 31.

Therefore, the subtracter 23 (U ₂ −
U ₋₂ ) is obtained, the subtractor 24 obtains (U ₁ −U ₋₁ ), the doubling circuit 29 obtains 2 (U ₂ −U ₋₂ ), and the adder 30 finally obtains , (2U ₂ + U ₁ −U ₋₁ −2U ₋₂ ) constituting the molecule is obtained. The adders 25 to 28 form a denominator (U _-2 + U _-1 + U).
₀ + U ₁ + U ₂ ) is obtained. Therefore, in the divider 31, (2U ₂ + U ₁ -U _-1 -2U _-2 ) / (U _-2 + U _-1 +)
U ₀ + U ₁ + U ₂ ) is executed and the output D 0 is obtained. Even in this circuit example, if negative if necessary,
We will calculate the borrow of D1.

By assembling the circuit with the digital circuit in this way, it is possible to perform accurate calculations faster than with the analog circuit. In particular, in the case of an analog divider, it is difficult to obtain a good performance in terms of accuracy and speed, so the merit of digital calculation is great.
In addition, the adder / subtractor used in the circuit of FIG. 7 can be configured in one chip by using a programmable device or a gate array, and the A / D converter is also integrated into an IC and can be obtained at low cost. For this reason, an inexpensive circuit with high accuracy and high speed can be assembled as a whole.

Although the above circuit is composed of a digital device, it may be composed of a one-chip microcomputer, DSP, or microprocessor if the calculation time is allowed.

Further, in the above embodiment, the decision circuit is
The method of selecting the point that outputs the maximum value signal has been described, but as a method of obtaining other maximum values, which of the two adjacent points is larger is compared with the comparator, and the larger one is selected with the analog switch, then It is also possible to select the larger one of the selected and reduced signals by half in the same manner, and finally obtain one output point.

Further, instead of simply obtaining the maximum value,
It is also possible to find the position having the peak showing the maximum value and the position having the second peak, and find out which is the true position from the previously found positions. In this case, since the measurement is performed continuously, the change in position between the previous time and this time should be less than a certain value, and the position of the first peak obtained last time, the position of the second peak, and the true position selected from them. Then, the true position of this time can be determined from the position of the first peak and the position of the second peak of this time. FIG. 8 shows a case where a decision circuit for performing such a decision, a signal switching circuit as in the above-described embodiment, and an arithmetic circuit for calculating a detailed position are incorporated in a one-chip microcomputer equipped with an A / D converter. 2 shows a circuit configuration of a detection circuit 11 composed of a PSD having n divisions, and a current-voltage conversion amplifier Ai for converting and amplifying the output current Ti of each division.
And a determination circuit that determines an output point indicating an approximate position D1 of the target object with respect to the output voltage signal Vi of each current-voltage conversion amplifier Ai, and an approximate position D1 of the target object determined by this determination circuit and It is composed of a switching circuit for selecting and switching the signals of a plurality of adjacent output points, and a microcomputer 32 in which an arithmetic circuit for calculating the detailed position D0 from the signals of the output points selected by the switching circuit is incorporated as a software program. can do.

As still another embodiment of the present invention, as a method of calculating a detailed position by an arithmetic circuit, instead of performing the center of gravity calculation, an approximate function such as a quadratic function or a Gaussian distribution curve is approximated to obtain an approximate expression. It is possible to adopt a method of obtaining the center of the as a detailed position. The approximation in this case can be calculated by the well-known least squares method.

In any of the above embodiments,
One P is used as a light incident position detection element that constitutes the detection unit.
The SD is provided with a plurality of sections, and the light incident position is determined from the output current signals at both ends of each divided section. However, the present invention is not limited to this, and a plurality of light incident position detection elements may be provided as shown in FIG. Of the PSDs adjacently arranged one-dimensionally, a determination circuit at an approximate position with respect to the output current signals at both ends of each PSD, a switching circuit for performing switching selection of the input signal based on the determination result of the determination circuit, The object shape detection device of the present invention can also be configured by connecting an arithmetic circuit for calculating the position.

[0049]

As described above, according to the present invention, the semiconductor position detecting element is divided into a plurality of parts, and the detecting portion or the plurality of semiconductor position detecting elements which are output from the respective divided sections are provided.
Multiple output from the multiple divisions of the corresponding position of the semiconductor position detection element or from the plurality of semiconductor position detection elements of the corresponding position according to the light receiving position of the reflected light from the surface of the object Is output to the determination unit at the same time, and the determination unit outputs an output indicating the approximate position of the target object with respect to the plurality of inputs from the plurality of divided sections or the plurality of inputs from the plurality of semiconductor position detecting elements. A point is determined, and the switching unit selects and switches the approximate position of the target object determined by this determination unit and signals at a plurality of output points adjacent thereto, and based on the signal at the output point selected by this switching unit. , The calculation unit is designed to calculate the detailed position of the target object, so first specify the approximate position of the target object, and then determine the position adjacent to the approximate position. Te with reference to the outputs of the plurality of output or a plurality of semiconductor position detecting elements of the split segment of the semiconductor position detecting element, it is possible to determine the detailed position of the target object, the following effects.

That is, since the approximate position is judged from the output of each output point at the same time, an erroneous light spot formed by multiple reflections is deleted, and an erroneous measurement is made by the arithmetic unit for simply calculating the PSD as a single PSD. Can be prevented.

When obtaining the approximate position, 1
If the barycentric position is obtained from the signals at the output points at both ends in terms of two PSDs, the resistance of the PSD will increase by the number of divisions, and the delay due to the time constant with the capacitance will significantly increase the measurement time. According to this, each section has one PSD
As the resistance increases, the time constant does not increase and high speed can be secured.

In addition, the number of PSD categories increases,
If the light spots of the optical system have spread over multiple adjacent sections, simply calculate the position from the two adjacent output points, or use the output points corresponding to both ends of the light point without using the intermediate points. Then, the case where the correct position cannot be measured, the resolution is reduced, the speed is reduced, etc. According to the present invention, the centroid calculation or the function approximation is always performed based on the outputs of three or more places. Highly accurate position detection is possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a hardware configuration of an optical system of a general object position detecting device.

FIG. 2 is an optical diagram illustrating an object position detection principle based on a triangulation method of a general object position detection device.

FIG. 3 is a circuit block diagram of an embodiment of the present invention.

FIG. 4 is a circuit block diagram showing a detailed internal configuration of a determination circuit in the above embodiment.

FIG. 5 is a circuit block diagram showing a detailed internal configuration of a switching circuit in the above embodiment.

FIG. 6 is a circuit block diagram showing a detailed internal configuration example of an arithmetic circuit in the above embodiment.

FIG. 7 is a circuit block diagram showing another example of the internal configuration of the arithmetic circuit in the above embodiment.

FIG. 8 is a circuit block diagram of another embodiment of the present invention.

FIG. 9 is an explanatory diagram of a conventional semiconductor position detecting element.

FIG. 10 is a circuit block diagram of a conventional position calculation circuit.

FIG. 11 is an explanatory diagram of a light incident position detection element having a configuration in which a plurality of divided sections are provided in one general PSD.

FIG. 12 is an explanatory diagram of a light incident position detection element configured by a plurality of general PSDs.

FIG. 13 is an explanatory diagram showing a case in which a light spot spreads to three or more output points that cause erroneous detection in the conventional example.

FIG. 14 is an explanatory diagram showing an example of double reflection that causes erroneous detection in the conventional example.

FIG. 15 is an explanatory diagram showing an output state on the PSD in the case of the above-mentioned reprinter.

[Explanation of symbols]

 1 Laser Light Source 2 Lens 3 Motor 4 Galvano Mirror 5 Stage 6 Target Object 7 Imaging Lens 8 Light Incident Position Detection Element 11 Detection Circuit 12 Judgment Circuit 13 Switching Circuit 14 Arithmetic Circuit A0-An Current-Voltage Conversion Amplifier L Laser Light

Claims (2)

[Claims] 1. An object shape detecting device for focusing light emitted from a light source to irradiate an object, forming an image of reflected light from the surface of a target object, receiving the image, and outputting an electric signal according to the received position. , A semiconductor position detecting element is divided into a plurality of, and a detection unit that outputs a detection signal from each division, and a plurality of outputs from the plurality of divisions of the detection unit are input at the same time to obtain the approximate position of the target object. A determination unit that determines the output point, a switching unit that selects and switches the approximate position of the target object determined by the determination unit and signals of a plurality of output points adjacent thereto, and the output point selected by the switching unit. Object shape detecting device comprising a calculation unit for calculating a detailed position from the signal of. 2. The object shape detecting apparatus according to claim 1, wherein a plurality of semiconductor position detecting elements adjacent to each other in a one-dimensional arrangement are used instead of the detecting unit, and the plurality of semiconductor positions of the detecting unit are used. An object shape detection device, wherein a plurality of outputs from a detection element are input to the determination unit at the same time.