JP2000121388A - Optical encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoder in which a high-accuracy and very small interval positioning arrangement between a scale and a detecting head is not required, whose whole constitution is simple and which is miniaturized. SOLUTION: Beams of incident light Li (Li1 to Li3) from a light source 10 are changed into beams of parallel light by a lens 11 so as to be incident on the sinusoidal optical characteristic face 13a of a scale 13. Beams of reflected light Lr (Lr1 to Lr3) from the optical characteristic face 13a are received by a light receiving element 12. When sinusoidal photoelectric conversion outputs which are obtained by detecting a change in a quantity of received light which is repeated periodically by the movement of the scale 13 are counted, the movement distance of the scale 13 is detected. When phase difference signals at a 1/4 pitch are compared, the movement direction of the scale 13 is detected. The beams of very-small-spot incident light Li are incident on the optical characteristic face 13a. The beams of reflected light Lr can be detected at high resolution and with high accuracy. A sufficient interval can be set between a detecting head 15 and the optical characteristic face 13a. A damage accident due to their mutual contact is prevented. The movement due to the vibration in a direction at right angles to the movement direction of the scale 13 can be permitted. An optical encoder can be constituted in such a way that its complicated positioning adjustment is not required as a whole, that it is simple and that it is miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a light source and a scale to which test light from a light source is irradiated are relatively moved.
The present invention relates to an optical encoder that detects a change in a relative position between a light source and a scale based on reflected light of a scale of inspection light.

[0002]

2. Description of the Related Art A conventional optical encoder has a configuration as shown in FIG. 20 and is closely opposed to a scale 3 provided with an optical grating having a predetermined lattice constant and has the same lattice constant as the scale 3. An index scale 4 having an optical grating and an optical grating shifted from the optical grating by 光学 wavelength is provided, and detectors 5 and 5 ′ are respectively opposed to two kinds of optical grating positions of the index scale 4. Are located.

In this optical encoder, light from a light source 1 is irradiated on a scale 3 as collimated inspection light by a collimating lens 2 and the scale 3 is moved in the direction of an arrow 6. Inspection lights respectively passing through the optical gratings of the scale 4 shifted by １ ／ wavelength are detected by the detectors 5 and 5 ′, respectively. For this purpose, the detectors 5 and 5 'detect changes in the amount of received light corresponding to the movement of the scale 3 by the optical grating of the scale 3 and the index scale 4, and count the photoelectrically converted detection signals. Thus, the moving amount and moving direction of the scale 3 are detected.

[0004]

In the above-mentioned conventional optical encoder, it is necessary to use a scale 3 having a small lattice constant in order to increase the detection resolution. In this case, however, in order to maintain a high contrast. In this case, the scale 3 and the index scale 4 must be arranged to face each other at a minute interval, so that damage due to contact between them is liable to occur, and a large error occurs in the detection value even due to minute dust adhesion. Sometimes.

Further, in the conventional optical encoder, since the head section containing the light source 1 and the collimating lens 2 is disposed close to and opposed to the scale 3, when the scale 3 vibrates in the optical axis direction of the head section. Also, there is a problem that damage is easily caused by contact between the two.

[0006] The present invention has been made in view of the current state of operation of such an optical encoder as described above.
It is an object of the present invention to provide an optical encoder which does not require a highly precise positioning between a scale and a detection head at a minute interval, has a simple overall configuration, and is miniaturized.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, the inspection light from the light source repeatedly and periodically changes its light reflection characteristic periodically and continuously in the direction of relative movement. By irradiating a scale having an optical characteristic surface, the light source and the scale are relatively moved in the relative movement direction, and reflected light of the inspection light from the optical characteristic surface is
Received by the light receiving means, based on the amount of light received by the light receiving means,
An optical encoder for detecting a change in a relative position between the light source and the scale, wherein the same uneven surface shape is periodically and continuously repeated on the optical characteristic surface. It is.

[0008] Similarly, in order to achieve the above-mentioned object, the invention according to claim 2 is directed to an optical characteristic surface in which inspection light from a light source periodically and continuously changes its reflection characteristic periodically and continuously in the direction of relative movement. Irradiating the scale provided, the light source and the scale are relatively moved in the relative movement direction, the reflected light of the inspection light from the optical characteristic surface is received by light receiving means, the light receiving means An optical encoder that detects a change in the relative position between the light source and the scale based on the amount of received light, and the optical characteristic surface has two adjacent surfaces.
A unit array of V-grooves arranged opposite to each other at a predetermined inclination angle with respect to the horizontal base axis is periodically and repeatedly formed, and the reflected light from the reflecting surface is changed in the relative position. Light guide means for guiding the light to the light receiving means by changing the amount of incident light in accordance therewith is provided.

[0009] Similarly, to achieve the above object, a third aspect of the present invention is characterized in that, in the second aspect of the present invention, the predetermined inclination angle is 45 °.

Similarly, in order to achieve the above object, the invention according to claim 4 is different from the invention according to claim 2 or 3 in that the light guide means guides the light immediately before the light receiving means. A mask body in which the amount of transmitted light changes corresponding to the position of the reflected light is provided.

[0011] Similarly, in order to achieve the above object, according to a fifth aspect of the present invention, in the fourth aspect of the present invention, the mask body is configured such that the light guide means guides the light corresponding to the relative movement. The width of the opening through which the reflected light is transmitted changes in the direction of movement of the reflected light.

[0012] Similarly, in order to achieve the above object, according to a sixth aspect of the present invention, in the fourth aspect of the present invention, the mask body is configured so that the light guiding means guides the light in accordance with the relative movement. The structure is such that the transmittance of the reflected light changes in the moving direction of the reflected light.

[0013] Similarly, in order to achieve the above object, the invention according to claim 7 is the invention according to any one of claims 1 to 3, wherein the light receiving means is a light receiving surface corresponding to the relative movement. A light receiving area divided into a plurality in the moving direction of the reflected light is provided.

According to another aspect of the present invention, in order to achieve the above-mentioned object, the light-receiving means may include a light-receiving surface corresponding to the relative movement. It is characterized by having a divided light receiving area at the center of the movement of the reflected light and at the periphery thereof.

Similarly, in order to achieve the above object, a ninth aspect of the present invention is the same as the fourth aspect of the invention, except that the distance between the mask body and the light receiving means is smaller than that of the fourth aspect.
A lens for converging the reflected light from the mask body on a light receiving surface of the light receiving means is provided.

Similarly, in order to achieve the above object, a tenth aspect of the present invention provides a method according to any one of the first to third aspects, wherein a plurality of inspection lights are created from the light source. A plurality of inspection light irradiating means for simultaneously irradiating the plurality of inspection lights to the optical characteristic surface of the scale is provided.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is an explanatory front view showing the configuration of the present embodiment, and FIG. 2 is an explanatory side view showing the configuration of the present embodiment.

In the present embodiment, as shown in FIGS. 1 and 2, the detection head 15 containing the light source 10, the lens 11, and the light receiving element 12
An optical characteristic surface 13a having a cross section of a period T1 and having a sine wave shape is formed on a surface of the scale 15 facing the detection head 15. As the light source 10, a semiconductor laser that generates inspection light for a minute spot where aberration is unlikely to be generated is used.
A lens having a function of collimating the inspection light from the light source 10 into parallel light is used as the lens 11, and a photodiode is used as the light receiving element 12.

The operation of this embodiment having such a configuration will be described. In the present embodiment, as shown in FIG.
The incident light Li from 0 is incident on the lens 11 and collimated into parallel light, and the optical characteristic surface 13a of the scale 13
And the reflected light Lr from the optical characteristic surface 13 a is received by the light receiving element 12. In this case, as shown in FIG. 1, when the scale 13 is moved in the direction of the arrow X with respect to the detection head 15, the inspection light from the light source 10
The incident position on the optical characteristic surface 13a continuously changes like the incident light Li1, Li2, Li3..., And the reflected light from the optical characteristic surface 13a is reflected light Lr1, Lr2, L
By changing the reflection angle as in r3.
3a.

For this reason, the sinusoidal optical characteristic surface 13a that is periodically repeated with the movement of the scale 13
The amount of light received by the light receiving element 12 from the reflected light Lr changes periodically and repeatedly. Therefore, in the present embodiment, the output signal photoelectrically converted by the light receiving element 12 is also output as a sine wave, and the movement distance of the scale 13 is detected by counting this output signal. The direction of movement of the scale 13 is detected by comparing the phase difference A and B phase signals.

As described above, according to the present embodiment, the inspection light from the light source 10 of the semiconductor laser is a minute spot, and this inspection light is collimated into parallel light by the lens 11 and is applied to the optical characteristic surface 13a. Incident as the incident light Li,
Since the reflected light Lr from the optical characteristic surface 13a is received by the light receiving element 12, it is possible to detect the reflected light Lr with high resolution and high accuracy.

Further, the detection head 15 and the optical characteristic surface 13a of the scale 13 can be arranged with a sufficient space therebetween, thereby preventing damages due to mutual contact and preventing the scale 13 from moving in a direction perpendicular to the moving direction of the scale 13. This makes it possible to allow movements such as vibrations to the outside, so that it is possible to provide a simple and compact configuration without any complicated positioning adjustment.

[Second Embodiment] A second embodiment of the present invention will be described with reference to FIGS. 3 is an explanatory diagram showing the configuration of the present embodiment, FIG. 4 is an explanatory diagram of a light receiving operation of the present embodiment, FIG. 5 is an explanatory diagram of a change in the amount of received light of the present embodiment, and FIG. FIG. 5 is an explanatory diagram when the detection head is tilted.

In this embodiment, as shown in FIG. 3, instead of the optical characteristic surface 13a having a sinusoidal cross section of the first embodiment, two adjacent surfaces are provided on the optical characteristic surface 13b of the scale 13. But 45 with respect to the horizontal base axis. The unit arrangement of the V-grooves arranged to face each other at an inclination angle of is periodically and continuously formed repeatedly. In addition, the detection head 15A
Has a beam splitter 1 having a translucent reflecting surface 16a.
6 is newly accommodated. The beam splitter 16 is disposed between the lens 11A and the optical characteristic surface 13b.
Numeral 2 is disposed on the side of the beam splitter 16 with the light receiving surface parallel to the optical axis of the inspection light.

The configuration of the other parts of the present embodiment is the same as that of the first embodiment already described with reference to FIGS. 1 and 2, and therefore, will not be described repeatedly.

In the present embodiment, the incident light Li from the light source 10 is incident on the lens 11, is collimated into parallel light, and is incident on the beam splitter 16 as inspection light.
The inspection light transmitted through the translucent reflection surface 16a is
The inspection light that is incident on one surface of the optical characteristic surface 13b constituting the unit array of the V-grooves is reflected in the horizontal direction from the one surface and the adjacent inspection light that constitutes the unit arrangement of the V-grooves The light enters the other surface, is reflected by the other surface, and enters the beam splitter 16 as reflected light parallel to the incident inspection light. Of the reflected light incident on the beam splitter 16, the reflected light reflected in the horizontal direction on the translucent reflecting surface 16 a is incident on the light receiving element 12 at right angles to the light receiving surface, and the amount of light received corresponding to the movement of the scale 13. Is received by the light receiving element 12.

The light receiving operation in this case will be described.
In (a), the reflected light Lr from the optical characteristic surface 13b of the scale 13 with respect to the incident light Li slightly enters the light receiving surface of the light receiving element 12, and the light receiving element 12 receives the reflected light Lr with low light receiving intensity. When the scale 13 moves to the state shown in FIG. 3B, all of the reflected light Lr reaches the light receiving surface of the light receiving element 12, the light receiving intensity of the light receiving element 12 becomes maximum, and the scale 13 further moves. When the state shown in FIG.
The light receiving intensity of the light receiving element 12 slightly decreases.

FIG. 5 shows this light receiving operation of the light receiving element 12, and as shown in FIG. 4A, in the state of FIG. Li
Is incident on the small light receiving area 18a, and as shown in FIG. 4B, in the state of FIG. 4B, the incident light Li is incident on the entire light receiving surface 17 of the light receiving element 12 as the light receiving area 18b. As shown in FIG. 4C, in the state of FIG.
The incident light Li enters the light receiving region 18c having an intermediate area.

As described above, with the movement of the scale 13, the amount of light received by the light receiving element 12 of the reflected light Lr from the optical characteristic surface 13a on which the unit V groove that is periodically repeated is continuously formed is also periodically changed. An output signal which changes repeatedly and is photoelectrically converted by the light receiving element 12 is also output corresponding to the V-groove. Therefore, by counting this output signal,
The moving distance of the scale 13 is detected, and the moving direction of the scale 13 is detected by comparing the A-phase signal and the B-phase signal having a phase difference of 1/4 pitch.

In particular, in this embodiment, as shown in FIG. 6, even if the detection head 15A is tilted for some reason during measurement, the groove angle of the V-groove in the unit of the optical characteristic surface 13a of the scale 13 is 90 °.゜, the incident light Li
And the reflected light Lr are always parallel, and the translucent reflection surface 16
The reflected light Lr reflected at a is always incident on the light receiving surface of the light receiving element 12 at a right angle, the diffusion of the light is completely prevented, the inclination of the detection head 15A is compensated, and the movement amount of the scale with high accuracy is always obtained. Can be measured.

As described above, according to this embodiment, in addition to the effects obtained in the first embodiment already described,
By the beam splitter 16, the reflected light Lr from the optical characteristic surface 13a of the scale 13 is effectively converged in the direction of the light receiving element 12, the detection intensity range of the reflected light Lr by the light receiving element 12 is expanded, and the detection sensitivity is increased. Independently of the distance between the scale 13 and the detection head 15A, it is possible to detect the movement amount and the movement direction of the scale 13 with higher accuracy, and to compensate for the inclination of the detection head 15A at the time of measurement, and to always obtain high accuracy. Can be detected.

Third Embodiment A third embodiment of the present invention will be described with reference to FIG. FIG. 7 is an explanatory diagram showing the configuration of the present embodiment.

This embodiment is different from the above-described second embodiment in that two adjacent surfaces have an inclination angle smaller than 45 ° with respect to the horizontal base axis on the optical characteristic surface 13c of the scale 13. The unit arrangement of the V-grooves arranged to face each other is repeatedly formed periodically and continuously. Therefore, in the present embodiment, the groove angle of the unit V groove is larger than 90 °.

The configuration of the other parts of the present embodiment is the same as that of the second embodiment already described, and therefore will not be described repeatedly.

In this embodiment, the incident light Li from the light source 10 is incident on the lens 11 and collimated into parallel light, and is incident on the beam splitter 16 as inspection light.
The inspection light transmitted through the translucent reflection surface 16a is
The inspection light that is incident on one surface of the unit array of the V-grooves of the optical characteristic surface 13c is reflected from the one surface, and the other adjacent surface that constitutes the unit array of the V-grooves And reflected by the other surface, and is incident on the beam splitter 16 as reflected light substantially parallel to the incident inspection light. Of the reflected light incident on the beam splitter 16, the reflected light reflected on the translucent reflecting surface 16a is emitted toward the light receiving element 12, and the reflected light reaching the light receiving surface is received according to the movement of the scale 13. The light is received by the element 12.

As described above, as the scale 13 moves, the amount of light received by the light receiving element 12 of the reflected light Lr from the optical characteristic surface 13c in which the unit V grooves that are periodically repeated are continuously formed is also periodically changed. An output signal which changes repeatedly and is photoelectrically converted by the light receiving element 12 is also output corresponding to the V-groove. Therefore, by counting this output signal,
The moving distance of the scale 13 is detected, and the moving direction of the scale 13 is detected by comparing the A-phase signal and the B-phase signal having a phase difference of 1/4 pitch.

According to the present embodiment, in addition to the effects obtained in the first embodiment already described, the beam splitter 16 allows the reflected light Lr from the optical characteristic surface 13c of the scale 13 to be transmitted to the light receiving element 12 Converges effectively to
The detection intensity range of the reflected light Lr by the light receiving element 12 is expanded to increase the detection sensitivity, and the scale 13 and the detection head 15 are increased.
The movement amount and movement direction of the scale 13 can be detected with higher accuracy without depending on the distance between B.

[Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 8, this embodiment is different from the second embodiment already described with reference to FIG. 3 in that a filter 20 and a light receiving lens are newly provided in place of the detection head 15A. A detection head 15B additionally containing 21 is used, and a light receiving lens 21 is disposed immediately before the light receiving element 12,
Between the beam splitter 16 and the light receiving lens 21, the reflected light L
A filter 20 having a different amount of transmitted light depending on the incident position of r is provided.

As shown in FIG. 9, the pass width of the reflected light Lr of the filter 20 changes with respect to the change direction X of the incident position of the reflected light Lr from the translucent reflecting surface 16a of the beam splitter 16. The filter 20A in which the opening 22 is formed can be used. Further, as shown in FIG. 10, the translucent reflection surface 16 of the beam splitter 16 is provided.
With respect to the change direction X of the incident position of the reflected light Lr from a,
By changing the thickness, the filter 20B in which the transmittance of the reflected light Lr is changed can be used.

The configuration of the other parts of the present embodiment is the same as that of the second embodiment already described, and therefore, will not be described repeatedly.

In this embodiment, as the filter 20,
The case where the filter 20A having the opening 22 shown in FIG. 9 is used will be described. The reflected light Lr from the translucent reflecting surface 16a of the beam splitter 16 is located at a position on the filter 20A corresponding to the moving position of the scale 13. Incident. For this reason, the amount of reflected light Lr corresponding to the degree of opening of the opening 22 at that position is converged by the light receiving lens 21 in the optical axis direction of the light receiving element 12 and is incident on the light receiving element 12 and received.

As described above, the amount of light Lr reflected by the light receiving element 12 from the optical characteristic surface 13b on which the unit V-groove periodically repeated with the movement of the scale 13 is continuously formed by the filter 20A. The output signal, which is periodically and repeatedly changed in proportion to the opening width of the opening portion 22 of FIG.

In this case, since the change in the amount of light within one cycle corresponds to the incident position of the reflected light Lr of the filter 20A, the moving distance of the scale 13 is detected by counting the output signal of the light receiving element 12. Further, the position of the reflected light Lr is detected with high accuracy based on the intensity of the output signal of the light receiving element 12, and the moving direction of the scale 13 is immediately detected by increasing or decreasing the output signal of the light receiving element 12.

The same applies to the case where the filter 20B shown in FIG. 10 is used as the filter 20, and the transmittance of the reflected light Lr changes according to the incident position of the reflected light Lr on the filter 20B indicated by the arrow X. Therefore, the intensity of the output signal of the light receiving element 12 changes linearly in the direction of the arrow X, and the intensity of the output signal of the light receiving element 12 detects the position of the reflected light Lr with high accuracy. The movement direction of the scale 13 is immediately detected by the increase or decrease of the distance.

As described above, according to the present embodiment, in addition to the effects obtained in the second embodiment already described,
By detecting the increase or decrease of the output signal of the light receiving element 12, the moving direction of the scale 13 can be determined, and a circuit for comparing the A-phase signal and the B-phase signal of the phase difference of 1/4 pitch of the light receiving element 12 is provided. This is unnecessary, and the entire configuration can be simplified and downsized.

[Fifth Embodiment] A fifth embodiment of the present invention will be described with reference to FIGS.

This embodiment is different from any of the first to third embodiments described above in that the area of the light receiving surface as the light receiving element 12 is divided into two and the output of each area is divided. A light receiving element 12A capable of performing a signal difference calculation is used.

The configuration of the other parts of the present embodiment is the same as any of the first to third embodiments described above, and will not be described again.

In this embodiment, the scale 13 is provided for each of the light receiving areas 23A and 23B of the light receiving element 12A.
The amount of reflected light Lr from is detected, and the difference between the detected values is calculated. When the reflected light Lr moves from the light receiving area 23B side to the light receiving area 23A side, the difference calculated value of the detection values is as shown in FIG.
2, the zero cross point in the figure indicates that the reflected light Lr is located at the center of the light receiving surface of the light receiving element 12A.

As described above, according to the present embodiment, in addition to the effects obtained in any one of claims 1 to 3,
For each of the light receiving areas 23A and 23B of the light receiving element 12A, the amount of the reflected light Lr from the scale 13 is detected and the difference calculation is performed, so that the position of the reflected light Lr on the light receiving surface of the light receiving element 12A can be determined with high accuracy. It becomes possible to detect with.

[Sixth Embodiment] A sixth embodiment of the present invention will be described with reference to FIG. FIG. 13 is an explanatory diagram showing the configuration of the light receiving element of the present embodiment.

This embodiment is different from any of the first to third embodiments described above in that the light receiving surface is divided into a central part and a peripheral part as the light receiving element 12. Thus, a light receiving element 12B capable of executing a difference calculation of the output signal of each area is used. The configuration of the other portions of the present embodiment is the same as any of the first to third embodiments described above, and therefore, will not be described repeatedly.

In this embodiment, the scale 13 is provided for each of the light receiving areas 24A and 24B of the light receiving element 12B.
The amount of reflected light Lr from is detected, the difference between the detected values is calculated, and the position of the reflected light Lr on the light receiving surface of the light receiving element 12B is determined based on the obtained calculated value.

As described above, according to this embodiment, in addition to the effects obtained in any one of claims 1 to 3,
For each of the light receiving areas 24A and 24B of the light receiving element 12B, the amount of the reflected light Lr from the scale 13 is detected and the difference calculation is performed, so that the position of the reflected light Lr on the light receiving surface of the light receiving element 12B can be determined with high accuracy. It becomes possible to detect with.

[Seventh Embodiment] A seventh embodiment of the present invention will be described with reference to FIG. FIG. 14 is an explanatory diagram showing a configuration of a main part of the present embodiment.

This embodiment uses the light receiving elements 12C and 12D with respect to any one of the first to third embodiments described above.
The reflected light Lr incident on the central portion of the light receiving surface is received, and the light receiving element 12D receives the reflected light Lr incident on the peripheral portion of the light receiving surface.
Is configured to be received. That is, in the present embodiment, as shown in FIG.
12D is disposed, and the reflected light Lr from the scale 13 is
The light enters the beam splitter 37 and is reflected by the translucent reflection surface 37.
a through the filter 20B.
The light incident on 2C and reflected on the translucent reflection surface 37a is incident on the light receiving element 12D via the filter 20D.

The filter 20B has a light-transmitting region 2 at the center.
5A are formed, and a light shielding area 25B is formed around the light shielding area 5A.
B is formed, and a light-transmitting region 26A is formed around it.

The structure of the other parts of the present embodiment is the same as any of the first to third embodiments described above, and will not be described again.

In this embodiment, the light receiving elements 12C, 12C
D, the reflected light L from the scale 13
The light amount of r is detected, the difference between the detected values is calculated, and the position of the reflected light Lr on the light receiving surface is obtained based on the calculated value.

As described above, according to this embodiment, in addition to the effects obtained in any one of claims 1 to 3,
The light receiving elements 12C and 12D detect the amount of reflected light Lr from the scale 13 at the center of the light receiving surface of the light receiving element 12C and the amount of light around the light receiving element 12D, and the difference calculation is performed. Lr light receiving element 12C, 1
It is possible to detect the position on the light receiving surface of 2D with high accuracy.

[Eighth Embodiment] An eighth embodiment of the present invention will be described with reference to FIGS. 15 is an explanatory diagram of the light irradiation operation of the present embodiment, FIG. 16 is an explanatory diagram of the formation of the elliptical beam of the present embodiment, FIG. 17 is an explanatory diagram of the rectangular beam formation of the present embodiment, and FIG. FIG. 19 is an explanatory diagram of the formation of a plurality of rectangular beams according to the embodiment, and FIG. 19 is an explanatory diagram illustrating a configuration of a mask body for detecting a plurality of beams according to the embodiment.

As shown in FIG. 15, the first method of this embodiment is different from the conventional method in that the inspection light spot Ls1 is different from the conventional method.
Is a micro-focus light, and provides a method of compensating for a detection error of a movement amount of the scale 13 caused by a dirty portion 35 caused by, for example, minute dust adhering on the scale 13.

According to the first method of the present embodiment, as shown in FIG. 16, an elliptic inspection light is formed by a cylindrical lens 30 as compared with any of the first to seventh embodiments. Ls2 is formed, and this oblong inspection light Ls2 is
As shown in FIG. 5, the light is incident on the scale 13. In this case, instead of using the cylindrical lens 30, the light from the light source 10 is transmitted through the opening 3 as shown in FIG.
The inspection light Lsa having a rectangular shape may be formed by passing through the slit 31 in which 2 is formed.

According to the first method, the inspection light extending at right angles to the moving direction of the scale 13 is incident on the optical characteristic surface of the scale 13, so that the adverse effect of the dirt portion 35 due to minute dust is compensated for. The movement amount and direction of the scale 13 can be detected with high accuracy.

In the second system of the present embodiment, the light source 1 is provided in order to make the scale 13 more resistant to contamination.
The light from 0 passes through a slit 31A in which a plurality of rectangular openings 32a to 32f are formed as shown in FIG. 18, and is applied to the optical characteristic surface of the scale 13 as shown in FIG. A plurality of rectangular inspection lights Ls3a to Ls3e formed in parallel with each other at intervals are made to enter simultaneously.

Then, a plurality of rectangular inspections Ls3a to
Light Lr reflected from the optical characteristic surface of the scale 13 of Ls3e
Is received by the light receiving element through the filter 20D in which the wedge-shaped openings 36a to 36f are formed as shown in FIG. 19, or the filter 20B already described in FIG. 13, the scale 13 compensates for the adverse effects of the contaminated portion 35.
It is possible to detect the movement amount and direction of the object with high accuracy.

As described above, according to the present embodiment, even when the dirty portion 35 which adversely affects the optical characteristics is attached to the scale 13, the oblong shape or the rectangular shape long in the direction perpendicular to the moving direction of the scale 13 is provided. It is possible to detect the movement amount and direction of the scale 13 with high accuracy by compensating for the adverse effect of the contaminated portion 35 by simultaneously inputting a plurality of inspection light beams into the optical characteristic surface of the scale 13 at the same time. become.

The present invention is not limited to the above embodiment. For example, various detectors such as a light position detecting sensor (PSD) and a line sensor can be used as the light receiving means. As an optical characteristic surface, as a continuous surface, a corner cube cut at one corner of a cube, incident light in any direction is reflected in the opposite direction to the incident direction, not only the angle of the scale movement direction but also It is also possible to detect the angle in the direction perpendicular to the direction in which the scale moves, and it is also possible to use a scale that utilizes backside reflection with a refractive index distribution as the scale.

[0070]

According to the first aspect of the present invention, the same uneven surface shape of the inspection light from the light source is periodically changed so that the reflection characteristic of the light periodically and continuously changes in the relative movement direction. Light receiving means for irradiating a scale having an optical characteristic surface formed continuously and repeatedly, moving the light source and the scale relatively in a relative movement direction, and receiving reflected light of the inspection light from the optical characteristic surface Since the change in the relative position between the light source and the scale is detected based on the amount of received light, the detection head accommodating the light source and the light receiving means and the scale are arranged with sufficient spacing so as not to contact each other. In addition, it is possible to avoid damage due to contact and to allow movement of the scale in a direction perpendicular to the relative movement direction of the scale, and it is possible to achieve a simple and compact configuration without complicated positioning adjustment.

According to the second aspect of the present invention, the unit array of the V-grooves in which the inspection light from the light source is arranged so that two adjacent surfaces face each other at a predetermined inclination angle with respect to the horizontal base axis,
The light source and the scale are illuminated on a scale having an optical characteristic surface which is periodically and repeatedly formed, and whose light reflection characteristic periodically and continuously changes repeatedly in a relative movement direction. The reflected light from the optical characteristic surface of the inspection light is moved relative to the light source, and the light guide unit changes the incident light amount according to the change in the relative position and receives the light. Since the change in the relative position between the light source and the scale is detected, in addition to the effects obtained by the first aspect, the light receiving means is disposed close to the optical axis of the light source at right angles, and the overall configuration is made compact. Since the light guide means makes the reflected light incident on the light receiving surface of the light receiving means in a state where the light is less diffused, it is possible to detect the reflected light intensity with high accuracy.

According to the third aspect of the present invention, the inspection light from the light source is arranged such that the incident surface and the reflection surface are at 4 degrees with respect to the horizontal base axis.
5. The unit array of V-grooves that are arranged adjacent to each other at an inclination angle of the above is periodically and continuously formed repeatedly, and the optical reflection characteristic periodically and continuously repeatedly changes in the relative movement direction. Irradiated on a scale having a characteristic surface, the light source and the scale are relatively moved in the relative movement direction, and the reflected light of the inspection light from the optical characteristic surface is changed by the light guide means according to the change in the relative position. A change in the relative position between the light source and the scale is detected based on the amount of light received by the light receiving means that receives the light by changing the amount of incident light. Even if the detection head that houses the light receiving means is tilted, the reflected light is always incident on the light receiving surface of the light receiving means at a right angle, enabling more accurate detection of the reflected light intensity without any light diffusion. Become.

According to the fourth aspect of the present invention, in addition to the effects obtained by the second or third aspect of the present invention, the light guide means guides the reflected light by the mask disposed immediately before the light receiving means. Since the transmitted light amount of the reflected light changes according to the position of the light, the reflected light can be accurately positioned in one direction on the light receiving surface of the light receiving means of the reflected light, and the reflected light intensity can be accurately detected with high accuracy.

According to the fifth aspect of the present invention, the width of the opening through which the reflected light is transmitted is changed in the moving direction of the reflected light guided by the light guiding means in accordance with the relative movement. The effect obtained by the invention described in claim 4 is realized.

According to the sixth aspect of the present invention, a mask body having a structure in which the transmittance of the reflected light changes in the moving direction of the reflected light guided by the light guiding means in response to the relative movement. The effects obtained by the invention described in Item 4 are realized.

According to the seventh aspect of the present invention, in addition to the effect obtained by the first aspect of the present invention, the reflected light on the light receiving surface corresponding to the relative movement is provided to the light receiving means. In the moving direction of, there are provided a plurality of divided light receiving areas, so that the difference between the detection signals of the respective light receiving areas is calculated.
The light receiving position can be detected with high accuracy.

According to the eighth aspect of the present invention, in addition to the effects obtained by the first aspect of the present invention, the reflected light on the light receiving surface corresponding to the relative movement is provided to the light receiving means. The light receiving area is divided into the central part of the movement and the peripheral part, so it is possible to detect the light receiving position with high accuracy by calculating the difference between the detection signal of the central part and the detection signal of the peripheral part. Become.

According to the ninth aspect of the present invention, in addition to the effects obtained by any one of the fourth to sixth aspects, a lens provided between the mask body and the light receiving means allows the lens body to receive light from the mask body. Since the reflected light is converged on the light receiving surface of the light receiving means, efficient and highly accurate detection of the reflected light intensity becomes possible.

According to the tenth aspect, the first aspect is provided.
In addition to the effects obtained by the invention according to any one of claims 3 to 7, a plurality of inspection lights are generated from a light source by a plurality of inspection light irradiation units, and the plurality of inspection lights are simultaneously applied to the optical characteristic surface of the scale. Since the irradiation is performed, the contamination of the scale due to dust or the like is compensated, and the reflected light intensity can always be detected with high accuracy.

[Brief description of the drawings]

FIG. 1 is an explanatory front view showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is an explanatory side view showing the configuration of the embodiment.

FIG. 3 is an explanatory diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is an explanatory diagram of a light receiving operation of the embodiment.

FIG. 5 is an explanatory diagram of a change in received light amount according to the embodiment.

FIG. 6 is an explanatory diagram when the detection head according to the embodiment is tilted.

FIG. 7 is an explanatory diagram illustrating a configuration of a third exemplary embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a configuration of a fourth embodiment of the present invention.

FIG. 9 is an explanatory diagram illustrating a configuration example of a filter according to the embodiment;

FIG. 10 is an explanatory diagram illustrating a configuration example of a filter according to the embodiment;

FIG. 11 is an explanatory diagram illustrating a configuration of a light receiving element according to a fifth embodiment of the present invention.

FIG. 12 is a characteristic diagram showing intensity characteristics of a received light signal of the embodiment.

FIG. 13 is an explanatory diagram illustrating a configuration of a light receiving element according to a sixth embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a configuration of a main part of a seventh embodiment of the present invention.

FIG. 15 is an explanatory diagram of a light irradiation operation according to the eighth embodiment of the present invention.

FIG. 16 is an explanatory diagram of long elliptical beam formation according to the first embodiment.

FIG. 17 is an explanatory diagram of rectangular beam formation of the embodiment.

FIG. 18 is an explanatory diagram of forming a plurality of rectangular beams according to the embodiment.

FIG. 19 is an explanatory diagram showing a configuration of a mask body for multiple beam detection according to the embodiment.

FIG. 20 is an explanatory diagram showing a configuration of a conventional optical encoder.

[Explanation of symbols]

 Reference Signs List 10 light source 11 lens 12 light receiving element 12A light receiving element 12B light receiving element 13 scale 13a optical characteristic surface 13b optical characteristic surface 13c optical characteristic surface 15 detection head 15A detection head 15B detection head 16 beam splitter 20 filter 20A filter 20B filter 20C filter 20D filter

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA07 AA20 BB15 DD02 DD03 FF15 GG01 HH13 HH18 JJ07 KK01 MM02 MM16 MM26 QQ21 QQ51 UU05 UU06 UU07 2F103 BA17 BA37 BA43 CA03 DA01 EA05 EA15 EB15 EB21

Claims (10)

[Claims] An inspection light from a light source is irradiated on a scale having an optical characteristic surface whose light reflection characteristic periodically and continuously changes in the direction of relative movement, and the light source and the scale are connected to the scale. Moved relatively in the relative movement direction, the reflected light of the inspection light from the optical characteristic surface is received by the light receiving means, based on the amount of light received by the light receiving means, the relative position of the light source and the scale An optical encoder for detecting a change, wherein the same irregular surface shape is periodically and continuously repeated on the optical characteristic surface. 2. A scale having an optical characteristic surface whose light reflection characteristic periodically and continuously changes repeatedly in a relative movement direction with inspection light from a light source, wherein the light source and the scale are configured to Moved relatively in the relative movement direction, the reflected light of the inspection light from the optical characteristic surface is received by the light receiving means, based on the amount of light received by the light receiving means, the relative position of the light source and the scale An optical encoder that detects a change, wherein the optical characteristic surface has a unit array of V-grooves in which two adjacent surfaces are arranged to face each other at a predetermined inclination angle with respect to a horizontal base axis. Light guide means for changing the amount of incident light according to the change in the relative position and guiding the reflected light from the reflection surface to the light receiving means is provided. Optical encoder. 3. An optical encoder according to claim 2, wherein said predetermined inclination angle is 45 °. 4. The optical encoder according to claim 2, wherein the amount of transmitted light changes corresponding to the position of the reflected light guided by the light guiding means immediately before the light receiving means. An optical encoder, wherein a mask body is arranged. 5. The optical encoder according to claim 4, wherein the mask body has an opening for transmitting the reflected light in a moving direction of the reflected light guided by the light guiding means in response to the relative movement. An optical encoder characterized in that it has a structure in which the width of the lens changes. 6. The optical encoder according to claim 4, wherein the mask body changes the transmittance of the reflected light in a moving direction of the reflected light guided by the light guiding means in response to the relative movement. An optical encoder characterized in that the optical encoder has a structure to perform. 7. The optical encoder according to claim 1, wherein the light receiving unit is configured to move the reflected light on a light receiving surface corresponding to the relative movement in a moving direction of the reflected light.
An optical encoder having a plurality of divided light receiving regions. 8. The optical encoder according to claim 1, wherein said light receiving means comprises a central portion of a movement of said reflected light on a light receiving surface corresponding to said relative movement and a peripheral portion thereof. An optical encoder having a light receiving region divided into a plurality of light receiving regions. 9. The optical encoder according to claim 4, wherein said light receiving surface of said light receiving means receives said reflected light from said mask body between said mask body and said light receiving means. An optical encoder, comprising: a lens that converges on a lens. 10. The optical encoder according to claim 1, wherein a plurality of inspection light beams are generated from the light source, and the plurality of inspection light beams are simultaneously transmitted to the optical characteristic of the scale. An optical encoder comprising a plurality of inspection light irradiation means for irradiating a surface.