JPH01320430A - Optical displacement detector - Google Patents

Abstract

PURPOSE:To detect the displacement of an object by dividing the displacement between displacement related to movement and displacement related to inclination by utilizing the regular reflected light from the surface of the object. CONSTITUTION:Photodetector elements 16 and 18 are arranged on both sides of a diffraction grating 12 and the regular reflected light R1 of laser light L1 from the surface of an object is made incident on the light receiving surface of the photodetector element 16 and the regular reflected light R2 of laser light L2 from the surface of the object is made incident on the light receiving surface of the photodetector element 18. The elements 16 and 18 respectively output position signals indicating the positions of the light spots of the regular reflected light R1 and R2 on the light receiving surfaces parallel to the laser light reference planes including optical axes 2. Moving quantity calculating device 20 finds the displacement of the incident positions of 1st and 2nd regular reflected light R1 and R2 based on the detecting signals from the elements 16 and 18 and separately detects the inclination of the surface of the object and movement of 1st and 2nd detecting light L1 and L2 in the advancing direction based on both incident position displacement. Thus the displacement of the object can be detected by dividing the displacement between the displacement related to the movement and displacement related to the inclination.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention focuses on detecting light on the surface of an object, and detects the object based on the displacement of the arrival position of the reflected light from the surface of the object. It relates to an optical displacement detection device that detects the displacement of an object, such as whether or not the object has moved in the traveling direction of the detection light, whether the object surface is tilted, or the amount of movement or inclination. This invention relates to technology that improves the accuracy of detecting the displacement of objects.

[Prior Art] The above-mentioned optical displacement detection device generally includes (a) a light source that emits detection light, and b) receives reflected light from which the detection light is reflected on the surface of an object, and detects the incident position of the reflected light. and (C) displacement detection means for determining the displacement of the incident position of the reflected light based on the detection signal from the element and detecting the displacement of the object based on the displacement of the incident position. be done.

An optical displacement meter shown in FIG. 4 is already known as one type of optical displacement detection device. This consists of (a) laser drive circuits 100, each of which works together to irradiate the surface of the object 0 with laser light serving as detection light; a semiconductor laser 102 and a light projecting lens 104; (b) a light receiving lens 106 that collects diffusely reflected light R obtained by diffusely reflecting laser light on the surface of an object;
) The diffusely reflected light R collected by the light receiving lens 106
It has a light-receiving surface that receives the diffused reflected light R on the light-receiving surface.
(d) calculates the amount of displacement of the incident position based on the detection signal from the photodetecting element 110, and detects the laser beam of the object O according to the amount of displacement of the incident position; The semiconductor laser 102.
Light projection lens 104. The light receiving lens 106 and the photodetecting element 110 are arranged in the frame 1 of the displacement meter in a certain relative positional relationship.
It is fixed at 14. That is, in this conventional example, the laser drive circuit 100 and the semiconductor laser 10
2 is a light source, and the movement amount calculating means 112 is a displacement detecting means.

This type of optical displacement meter (hereinafter referred to as a diffused reflection type displacement meter) uses a fixed reference distance D from the object O before measurement.
Of the laser light irradiated from the semiconductor laser 102 to the surface of the object, the diffusely reflected light R from the surface of the object is perpendicularly incident on the light receiving surface of the photodetector 110, and the The diffusely reflected light R is made to reach a predetermined reference incident position on the light receiving surface.

When the object 0 moves from the reference position P0 in the traveling direction of the laser beam, the incident position of the diffusely reflected light R is within the plane that includes both the optical axis of the laser beam and the traveling direction of the diffusely reflected light R. The object O is displaced from the incident position by an amount corresponding to the movement amount S. Therefore, if the amount of displacement of the incident position of the diffusely reflected light R from the reference incident position is known, it is possible to calculate the movement IS of the object 0 and, by extension, the current distance to the displacement meter from that value.

[Problem to be solved by the invention]

In the above-mentioned diffused reflection light type displacement meter, the light reaching the photodetection element is diffusely reflected light from the surface of the object, so the light detected by the photodetection element has a low intensity and a low S/N ratio, and the It is not possible to sufficiently improve the accuracy of measuring the amount of movement.

On the other hand, if the amount of movement of the object is detected using specularly reflected light from the surface of the object, the signal-to-noise ratio of the light detected by the photodetecting element is improved and measurement accuracy is improved. However, in this case, the arrival position of the specularly reflected light is greatly affected by the inclination of the object surface, so if the object surface is inclined when measuring the amount of movement, an error may be included in the detection accuracy. .

Therefore, the present invention provides an optical displacement detection device that can detect the displacement of an object by dividing it into a displacement related to movement and a displacement related to tilt, using specularly reflected light from the surface of the object. This was done as a challenge.

[Means to solve the problem]

The gist of the present invention is to provide an optical displacement detecting device including the light source, a photodetecting element, and a displacement detecting means with first and second detection lights that propagate the detection light at a constant angle to each other within a reference plane. At the same time, a light splitter is provided that divides the first and second detection lights into two, and irradiates both detection lights obliquely and intensively onto the object surface at approximately the same angle. The device is composed of first and second photodetecting elements each receiving the reflected first and second specularly reflected lights and detecting the incident position of each specularly reflected light. The displacement of the incident position of the first and second specularly reflected lights is determined based on the detection signal from the photodetecting element, and the displacement of the object is detected based on the displacement of both of the incident positions.

In addition, when it is necessary to detect the inclinations within two reference planes that are perpendicular to each other, the light splitter is used to add the detection light to the first and second detection light and use the light splitter as the first reference plane. It is also divided into third and fourth detection lights that travel at a certain angle to each other within a second reference plane orthogonal to the first reference plane, and the third and fourth detection lights are each approximately equal to the surface of the object. At the same time, the third and fourth detection lights receive the third and fourth specularly reflected lights that are specularly reflected on the object surface, and the incident position of each specularly reflected light is determined. The displacement detecting means includes third and fourth photodetecting elements for detecting the displacement detecting means.
The incident position displacements of the third and fourth specularly reflected lights are also determined based on the detection signal from the fourth photodetecting element, and the incident position displacements of the first and second specularly reflected lights are determined within the first reference plane. It is preferable to include an inclination detection means for detecting the inclination of the object surface within the second reference plane based on the displacement of the incident position of the third and fourth specularly reflected lights. .

[Function] In the optical displacement detection device according to the present invention, the first and second detection lights are obliquely irradiated onto the first and second irradiation positions on the surface of the object, respectively, at substantially equal incident angles, and both of the detection lights are The first and second specularly reflected lights on the surface of the object enter the first and second photodetecting elements, respectively.

Therefore, the object and the detection device approach each other without the detection device and the surface of the object being tilted relative to each other, that is, while the angles of incidence of the first and second detection lights on the surface of the object are kept completely equal to each other. - In the simple moving state of separation, the first and second specularly reflected lights move by equal distances in opposite directions, and as a result, the incident position of the first specularly reflected light on the first photodetecting element (first The incident position) and the incident position (second incident position) of the second specularly reflected light onto the second photodetecting element are also displaced by equal distances in opposite directions. The amount of displacement of each incident position at this time corresponds to the amount of movement of the object.

On the other hand, a simple tilt state in which the angle of the object surface within the reference plane including the optical axes of the first and second detection lights changes by a small angle without the object moving; A state in which the object surface rotates by a small angle within the reference plane with the reference position, which is the center of the first and second irradiation positions, as the center of rotation (for purposes of explanation, the object surface rotates only within the reference plane, and in a plane perpendicular to it, (It shall not rotate.)
In this case, as a result of the first and second specularly reflected lights rotating at equal angles in the same direction around the first and second irradiation positions, respectively, the first and second incident positions are both displaced by approximately equal distances in the same direction. I will do it.

The first and second incident position displacement amounts at this time are the true incident position displacement amounts corresponding to the angular changes on the object surface, that is, the first and second incident position displacement amounts with the reference position on the object surface as the irradiation position.
and the incident position displacement that should be obtained when the target surface is rotated by a small angle around the reference position while keeping the reference position constant while being irradiated with detection light parallel to the second detection light. It doesn't exactly match the quantity. This is because one of the first and second irradiation positions approaches the corresponding photodetector element while the other moves away from the corresponding photodetector element due to the inclination of the object surface. When the incident surfaces of the first and second photodetecting elements are arranged parallel to the plane that directly faces the detection device, the first and second photodetecting elements may be
The angle formed by the - side of the specularly reflected light and the incident surface of the corresponding photodetecting element is larger after the tilt occurs than before the inclination occurs, whereas the angle formed by the other side of the first and second specularly reflected light This is because the angle formed by the incident surface of the photodetector and the corresponding incident surface of the photodetecting element becomes small. However, when the amount of change in inclination is small, both the first and second incident position displacement amounts can be considered to be equal to the true person's injection position displacement amount.

Therefore, if the object moves from the measurement start position to the measurement end position and the slope of the object surface is different at the start and end of the measurement, it is considered that the movement and the slope overlap. and either one of the first and second incident position displacement amounts (N by which the first and second incident positions are respectively displaced from the start of measurement to the end of measurement) corresponds to the amount of movement of the target object. Incident position displacement (
Hereinafter, this will be referred to as the amount of displacement related to movement. ) and the displacement amount of the incident position corresponding to the amount of change in inclination of the object surface (hereinafter referred to as the displacement amount related to inclination), whereas the other is the amount of displacement related to movement and the displacement amount related to inclination. The difference is the amount.

Hereinafter, the present invention will be described in detail, which is suitable for detecting the presence or absence of movement of a target object, the amount of movement, and the presence or absence of tilting of the surface of the target object, based on these displacement amounts.

First, when it is desired to measure the presence or absence and amount of movement of an object, more precisely, the presence or absence and amount of change in the distance between the reference position of the object and the displacement meter, the displacement detection means is movement detection means for calculating the average value of the displacement amount of the second incident position and detecting the presence or absence of movement based on the presence or absence of a change in the average value; and movement amount calculation means for calculating the movement amount from the amount of change in the average value. shall be included. By taking the average of both displacement amounts, the displacement amount related to the inclination of the first incident position and the displacement amount related to the inclination of the second incident position cancel each other out, so that only the displacement amount related to movement can be extracted. be.

Also, whether or not the angle of the object surface has changed, that is,
When it is desired to detect whether or not a tilt has occurred on the surface of the object, the displacement detection means calculates the difference between the displacement amount of the first and second incident positions, and if the value is 0, no tilt has occurred. and, if it is not 0, determines that a tilt has occurred. If we take the difference between the displacement of the first and second incident positions, the displacement due to the movement of the first incident position and the displacement due to the movement of the second incident position cancel each other out, which corresponds to the change in the inclination angle. Only the amount of displacement of the incident position (the amount of displacement related to the tilt) can be extracted.

〔Effect of the invention〕

As described above, according to the present invention, the movement and inclination of the object can be determined based on the amount of displacement of the incident positions of the first and second specularly reflected lights from the object surface onto the first and second photodetecting elements. Since the displacement of the target object can be detected separately, it is possible to improve the accuracy of detecting the displacement of the target object.

For example, in the above-mentioned embodiment in which the displacement detection means includes the movement amount calculation means, although the movement amount of the object is measured using specularly reflected light from the object surface, the angle of the object surface is The amount of movement of the object can be accurately measured almost independently of changes, and even if the surface of the object is tilted during measurement, the accuracy of measuring the amount of movement can be maintained at a good level.

The explanation so far has been based on the assumption that the amount of angular change on the object surface is small and that the amount of displacement of the first and second incident positions caused by the tilting of the object surface can be considered to be equal to the amount of displacement related to the tilt. However, even if the amount of angular change is larger than that, by irradiating the object surface with one detection light, the amount of displacement of the specularly reflected light on the object surface can be reduced. Compared to the case where the amount of movement of the target object is measured based on the above-described method, an effect can be obtained in that detection errors caused by angular fluctuations on the surface of the target object can be suppressed to a small value.

Furthermore, in the above-mentioned embodiment in which the displacement detection means includes the inclination detection means, it is possible to detect the inclination of the object surface with one detection device, which reduces measurement costs and facilitates measurement work. You can get the following effect.

Further, in this aspect, when detecting the inclination of the surface of the object, there is an effect that even if the object moves, the detection of the inclination is not hindered.

In the description of the embodiment in which the displacement detection means includes the movement amount calculation means, it is assumed that the object surface rotates only within the reference plane and does not rotate within the plane perpendicular to the reference plane. As a result of rotating in
When the first and second incident positions are displaced in a direction intersecting the reference plane, the length by which each incident position is displaced in a direction parallel to the reference plane may be treated as the amount of incident position displacement. In this way, the first and second incident position displacement amounts become displacement amounts related to the inclination of the object surface within the reference plane.

Further, according to the aspect including the third and fourth photodetecting elements, it is possible to detect not only the tilt in one reference plane but also the tilt in another reference plane perpendicular to the reference plane. can.

〔Example〕

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

FIG. 1 shows an optical displacement meter which is an embodiment of the present invention. In the figure, reference numeral 10 denotes a laser generator that irradiates the diffraction grating 12 with a laser beam having a wavelength λ. The diffraction grating 12 is one-dimensional with many slits lined up in a straight line at a constant grating pitch P. This diffraction grating 12 generates diffracted light of the laser beam, and among these diffracted lights, the ±1st-order diffracted lights are The laser beams, , L, respectively, are designed to reach the flat surface of the object 0 to be measured.

Since the output angle φ of the ±1st-order diffracted light is expressed as 5 in-' (λ/P), the grating pitch P of the diffraction grating 12 and the wavelength λ of the laser beam are selected so that the output angle φ is a predetermined angle. has been done. Note that 14 is a trap that prevents the 0th order diffracted light from the diffraction grating 12 from reaching the surface of the object. That is, in this embodiment, the laser generator 1
0 is a light source that emits a laser beam serving as detection light, the diffraction grating 12 is a light splitter, and lasers L, L2 are the first and second detection lights, respectively.

The optical displacement meter has a virtual measurement reference plane whose respective angles with the traveling direction of the laser beams, L, are a constant angle α, and the optical displacement meter, prior to measurement, The object surface is positioned approximately parallel to its measurement reference plane. That is, prior to measurement, the optical displacement meter is positioned so that the lasers L, , L are both incident on the surface of the object at approximately the incident angle α.

Photodetecting elements 16 and 18 are arranged on both sides of the diffraction grating 12, and the laser beam L10 specularly reflected light R on the object surface
, are arranged on the light-receiving surface of the photodetector 16, and specularly reflected light R2 of the laser beam L2 on the object surface is made incident on the light-receiving surface of the photodetector 18. The light receiving surfaces of both photodetecting elements 16 and 18 are parallel to the measurement reference plane and equidistant from the measurement reference plane.

Each of the photodetecting elements 16, 18 has a light receiving surface for each specularly reflected light R, .
When R, is incident, the specularly reflected light R+.

A position signal representing the position of the Rz light spot on the light receiving surface in a direction parallel to the laser beam reference plane including the optical axes of both the laser beam + and Lz is output. The magnitude of the position signal is determined to increase as the light spot position moves toward the diffraction grating 12. In other words, in this example, even if the object surface is tilted within the laser beam reference plane and also tilted within a plane perpendicular to that plane,
The difference between the two position signals obtained before and after the tilt occurs is almost the same as the difference between the position signals that should be obtained if the object surface is tilted only within the laser beam reference plane. This is how it is done.

When the object O is located at position P and the object surface there coincides with the measurement reference plane, the first light spot of the specularly reflected light R3 on the photodetecting element 16 is located at the point A0. , the second light spot of the specularly reflected light R2 on the photodetecting element 18 is point B.
Located at 0. From this state, the object O approaches the displacement meter in 1 s and reaches position P1, and if the object surface there also coincides with the measurement reference plane, the first light point will be at point A.
The second light spot is displaced to point A, which is away from point B0 to the left in the figure, and point B, which is away from point B0 to the right.

At this time, the amount of movement S of the object surface is equal to the height of triangle IJK in the figure, and the length of the base IJ of triangle IJK is the distance between point A0 and point A (hereinafter expressed as (Ao AI :l) .The same applies to other distances.) Tomo (Ba
B+ ) is also equal, so the movement amount S can be expressed as (Ao AI ) / (2t anφ) or (B
OB+ )/(2tanφ).

The object surface is generally not exactly parallel to the reference measurement plane. Therefore, as shown in FIG. 1, at position P0, the surface of the object is rotated by a small angle Δ in the counterclockwise direction in the figure, centering on the intersection between it and the bisector LD of the laser beams LI and Lz.
θ. Assume that it is in a rotated state, and has been rotated clockwise by a small angle Δθ1 at position P1.

In this case, first, at position P0, specularly reflected light RI,
As a result of Rz rotating in the same direction and at equal angles about the first and second irradiation positions on the surface of the object, respectively, the first light spot is a point A that is separated from point A0 to the left in the figure. ', while the second light spot is also at point B. The first irradiation position is shifted in the direction in which the position signal of the photodetecting element 16 increases, while the second irradiation position is displaced from the photodetecting element 1 to a point 80'' which is the same distance to the left as above.
The position signal of No. 6 is shifted in the decreasing direction, and the specularly reflected light R
The angle formed by I and the light receiving surface of the photodetecting element 16 (diffraction grating 1
The angle on the side of 2) is Δθ when the object surface is aligned with the measurement reference plane and directly faces the displacement meter.

While the angle formed by the specularly reflected light R2 and the incident surface of the photodetecting element 18 (the angle on the side of the diffraction grating 12) is larger in the rotated tilted state than in the tilted state, Since (AoAo °] and C
It does not exactly match BoBe tl. However, the tilt angle Δθ. Since (A
OAO') and (B, B, - are equal to each other, and both can be regarded as the amount of light spot displacement corresponding to the amount of change in the inclination of the object surface.

Therefore, point A. ' and point B. The positions of ' are expressed by the following equations (1) and (2), respectively.

AO'=A, 10C (Δθ.)...(1) B,'
=B, -C(Δθ.) (2) However, C(Δθ.)
θ. ), the object surface is at an angle Δθ at position P0.

represents the amount of light spot displacement corresponding to the rotation.

The position P1 can be considered in the same way as the position P0, and the positions of the point Al l and the points B and + are calculated by the following equation (3
) and (4).

A,'=A,-D (Δθ,)...(3)
B,'=B,+D (Δθ,) ・・・(4)
However, D(Δθ1) represents the amount of light spot displacement corresponding to rotation of the object surface by an angle Δθ at position P1.

A movement amount calculating device 2° is connected to the photodetecting elements 16 and 18. This movement amount calculating device 2o calculates the position P0 from the position signal of each photodetecting element 16.18 at the position P1.
The displacement amounts of the first and second light spots are respectively calculated by subtracting the position signals in , ① the average value of both displacement amounts is calculated, and ② the movement 1 s is calculated according to the average value.

The average value does not include the displacement amounts C (Δθ.) and D (Δθ1) that occur in response to changes in the inclination of the object surface, and the average value is the true light spot displacement amount corresponding only to movement -1 s, that is, (All AI 3 or (B.

It becomes BI3. In this way, in this embodiment, the true amount of light spot displacement can be obtained regardless of whether or not the surface of the object is tilted. That is, in this embodiment, the movement amount calculation device 20 is a displacement detection means that calculates the movement amount S of the object.

Note that the above description is for the case where the object O approaches the displacement meter, but the same applies to the case where the object O moves away from the displacement meter.

As is clear from the above explanation, in this example,
The amount of movement S of the object O is the regular reflection light R+, R on the object surface
z, the position detection accuracy of the first and second light spots of the specularly reflected lights R, , R2 of the photodetecting elements 16, 18 is improved, and the measurement accuracy of the movement 1 s of the object 0 is improved. The effect of improving this can be obtained.

In addition, in this embodiment, when measuring the movement amount S, the displacement meter is positioned so that the object O is located at a measurement reference position a certain distance D0 from the displacement meter, and is directly facing the displacement meter. This is no longer essential and is easy to measure. However, if the displacement meter is positioned so that the object is at the measurement reference position before measurement, then from the distance D0 between the displacement meter and the measurement reference position and the movement amount S calculated by the movement control device 20, It becomes possible to calculate the current distance between the displacement meter and the target object 0. In this case, it is not essential that the displacement meter be directly opposed to the surface of the object during the positioning.

In addition, in this embodiment, since it is only necessary to extract the displacement amount of the first and second light spots, the first and second light spots are located on the light receiving surface of the photodetecting element 16.18, respectively, of the diffraction grating 12. It is not necessary to determine the relative positions of both photodetecting elements 16.18 and the diffraction grating 12 so that the magnitudes of the position signals of the photodetecting elements 16.18 are equal to each other when they are located equidistant from the center. Those photodetecting elements 16,1
8 etc. is easy to install.

However, by arranging both photodetecting elements 16 and 18 with high precision at predetermined and equal distances from the center of the diffraction grating 12, the magnitude of the position signal can be adjusted according to the distance between the displacement meter and the target object. By setting it to a predetermined size and then calculating the average value of the position signal of the first light point and the position signal of the second light point, the current distance between the displacement meter and the object O can be calculated. Furthermore, it is not necessary to position the displacement meter at a predetermined distance from the measurement reference plane at the start of measurement.

Furthermore, in this embodiment, a diffraction grating 12 is used to divide the laser beam from the laser generator 10 so that the emission angle φ and intensity are equal to each other.
This has the effect of simplifying the structure of the light splitter and reducing the cost of the device.

In addition, in the embodiment described in detail above, the photodetector element 16
．． 18 light-receiving surfaces are parallel to the measurement reference plane,
Both light-receiving surfaces can be arranged at an angle such that specularly reflected light R, , R, which would be obtained if the object surface was parallel to the measurement reference plane, is incident perpendicularly. In this way, when a tilt occurs on the surface of the object, the amount of displacement of the light spot becomes equal with high accuracy for the first light spot and the second light spot, resulting in the effect of improving measurement accuracy. Note that this aspect is particularly meaningful when the amount of change in inclination of the surface of the object is relatively large.

FIG. 2 shows an embodiment in which the present invention is applied to a parallel movement device that moves an object while preventing the surface of the object from tilting with high precision.

In the figure, 30 is a moving mechanism that moves the object O in a direction perpendicular to its surface, and 32 is a movement control device that controls the operating state of the moving mechanism 30. Also, 34.36
are an X-direction angle correction mechanism and an X-direction angle correction mechanism for correcting the inclination angle in the X direction and the X direction of the object surface, respectively, and these are provided so as to be movable integrally with the moving mechanism 30.

Note that the X direction and the X direction are parallel to the object surface,
and the directions are orthogonal to each other. Each angle correction mechanism 34.
36 are the X-direction and X-direction angle correction control devices 4, respectively;
0.42, each control device 40.42 being controlled by each angle correction mechanism 34.42 in response to a correction signal supplied to it.
36 is activated. Moving mechanism 30 and angle correction mechanism 3
4.36 all use a piezoelectric element as a driving source.

A laser generator 10 is provided on the surface of the object as in the previous embodiment.
is irradiated with a laser beam emitted by A diffraction grating 44 as a light splitter is provided between the laser generator lO and the surface of the object, but this is different from the diffraction grating 12 of the previous embodiment, as shown in FIGS. 3(a) and (b). As shown in the example shown in FIG. This diffraction grating 44
As a result, the laser beam emitted by the laser generator 10 is divided into laser beams ,L, in addition to laser beams, ,L. At this time, the irradiation position of the laser beams, L, on the object surface is in the X direction, and the laser beam L3. The irradiation positions of L4 on the object surface are arranged in the X direction. The specularly reflected light R3°R2 of the laser beams L3, . L
The specularly reflected lights R3 and R4 on the object surface are incident on the photodetecting elements 46 and 48, respectively. The light receiving surfaces of the photodetecting elements 46 and 48 are located on the same plane as the photodetecting elements 16 and 18.

A correction signal output device 50 is connected to these photodetecting elements 16.1B and 46.48. This device 50 calculates the displacement amounts of the first to fourth light spots, which are the displacement amounts of the positions of the first to fourth light spots, from the position signals of the respective photodetecting elements 16.18, 46.48.

When the amount of light spot displacement is the same between the first light spot and the second light spot, a tilt in the X direction (laser light, tilt in the laser reference plane including the optical axes of both L2) occurs. If not, it is determined that a tilt in the X direction has occurred, and a correction signal is output. The correction signal output device 50 also determines the inclination in the X direction (within a laser reference plane including the optical axes of both laser beams L3 and L4) when the light spot displacement amounts match between the third and fourth light spots. The X-direction angle correction control device 42
However, if they do not match, it is determined that a tilt in the X direction has occurred, and a correction signal is output. That is, in this embodiment, a part of the correction signal output device 50 detects the presence or absence of a tilt in the X direction from the first and second light spot displacement amounts, and a part that detects the occurrence of tilt in the X direction from the third and fourth light spot displacement amounts. The portion that detects whether or not a tilt occurs constitutes a tilt detecting means.

As is clear from the above explanation, in this example,
The effect is that the inclination of the surface of the object 0 during movement is detected with high precision, and the inclination of the surface of the object 0 is prevented with high precision. Furthermore, the laser beams of the laser beams emitted by the laser generator 10, , L, , L3. Since the division into L, is performed by one diffraction grating 44, the cost of the light splitter device can be reduced.

In addition to the above two embodiments, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an optical displacement meter which is an embodiment of the present invention. FIG. 2 is a system diagram of an embodiment different from the above embodiment, and FIGS. 3(a) and 3(b) are front views schematically showing an example of a diffraction grating used in that embodiment. be. FIG. 4 is a system diagram of a conventional optical displacement meter. 10: Laser generator 12.44: Diffraction grating 16.1B, 46.48: Photodetection element 20: Movement amount calculation device 50: Correction signal output device Applicant: Toyota Industries Corporation, Figure 1

Claims (2)

[Claims] (1) A device that intensively irradiates the surface of an object with detection light emitted by a light source and detects the displacement of the object based on the displacement of the arrival position of the reflected light from the surface of the object, wherein the detection Light that divides light into first and second detection lights that travel at a constant angle to each other within a reference plane, and irradiates both detection lights obliquely and intensively onto the surface of the object, respectively, at approximately the same angle. a splitter, a first detecting light receiving the first and second specularly reflected lights, the first and second detection lights being specularly reflected on the object surface, and detecting the incident position of each specularly reflected light;
and a second photodetecting element. Based on the detection signals from these pixel elements, the displacements of the incident positions of both the specularly reflected lights are determined, and based on the displacements of the incident positions, the inclination of the surface of the object and the first and second photodetecting elements are determined. An optical displacement detection device including displacement detection means for separately detecting movement of the second detection light in the traveling direction. (2) The light splitter adds the detection light to the first and second detection lights and forms a certain angle with each other within a second reference plane orthogonal to the one reference plane serving as the first reference plane. It is also divided into third and fourth detection beams traveling by the third and fourth detection lights.
and a fourth detection light is irradiated obliquely and intensively onto the surface of the object at approximately the same angle, and the third and fourth detection lights are specularly reflected on the surface of the object. The displacement detecting means includes third and fourth photodetecting elements each receiving the fourth specularly reflected light and detecting the incident position of each specularly reflected light, and further, the displacement detecting means detects the detection from the third and fourth photodetecting elements. Based on the signal, the incident position displacements of the third and fourth specularly reflected lights are also determined, and based on the incident position displacements of the first and second specularly reflected lights, the surface of the object in the first reference plane is determined. 2. The method according to claim 1, further comprising a tilt detecting means for detecting the tilt and also detecting the tilt of the object surface within the second reference plane based on the displacement of the incident position of the third and fourth specularly reflected lights. Optical displacement detection device.