JPH11243258A - Optical encoder using surface-emitting semiconductor laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-emitting semiconductor laser which is capable of maintaining a stable output at all times, while avoiding the influence of returned light and also to provided an optical encoder which can be manufactured at low cost, with high resolution in a compact structure. SOLUTION: This optical encoder includes a scale 64 which is movable relative to a surface-emitting semiconductor laser 62 mounted on a substrate 76, and a light-receiving element 66 provided to the semiconductor laser, so that, when a part of the scale is illuminated with a laser beam emitted from the semiconductor laser, the element 66 receives a part of the light reflected by the scale. Also mounted on the semiconductor laser is a quarter-wavelength plate 68, which is in turn positioned so that the crystalline axis of the plate is shifted by 45 degrees with respect to the polarization plane of a laser beam 70a emitted towards the quarter-wavelength plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical encoder for detecting, for example, the amount of movement of a movable portion using a surface emitting semiconductor laser.

[0002]

2. Description of the Related Art Conventional surface emitting semiconductor lasers include, for example, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL.
9, As described on page 686 of SEPTEMBER 1990,
“Characteristics of To” described by YHLEE etc.
p-Surface-Emitting GaAs Quantum-Well Lasers "is known (hereinafter referred to as prior art 1).

As shown in FIG. 15, the laser of the prior art 1 has a semiconductor substrate 2 provided at a lower end thereof and an electrode provided at an upper end thereof and having an emission window 4a for emitting laser light. 4 is provided. Then, between the semiconductor substrate 2 and the electrode 4, an upper mirror 6 and a high resistance region 10 formed below the upper mirror 6 and having the active region 8 arranged at a position aligned with the emission window 4a. And a lower mirror 12 formed below the high resistance region 10.

According to such a configuration, a current injected into the electrode 4 flows from the upper mirror 6 to the semiconductor substrate 2 via the lower mirror 12 via the active region 8. At this time, the light emitted from the active region 8 is repeatedly reflected in the resonator constituted by the upper mirror 6 and the lower mirror 12. A part of the light excited by the laser oscillation passes through the upper mirror 6 and then exits from the exit window 4a.
From the laser light 14.

[0005] As a conventional optical encoder,
For example, an optical encoder disclosed in Japanese Patent Application No. 61-42677 is known (hereinafter, referred to as prior art 2).

As shown in FIG. 16, according to the optical encoder of the prior art 2, a laser beam emitted from a semiconductor laser 16 is converted into a parallel light beam by a collimator lens 18 and then moves via a beam splitter 20. Incident on the diffraction grating 22 a formed on the scale 22. At this time, the diffracted light diffracted from the diffraction grating 22a is
After being reflected by the first and second mirrors 24a and 24b and diffracted again, the light reaches the beam splitter 20 in a superimposed state, and is irradiated from the beam splitter 20 to the photodetector 26.

Since the photodetector 26 is configured to output an electric signal corresponding to the change in the intensity of the received light, the movement of the diffraction grating 22a is performed based on the electric signal output from the photodetector 26. The amount will be detected.

[0008]

However, the prior arts 1 and 2 have the following problems, respectively.

First, in prior art 1, IEEE PHOTONI
CS TECHNOLOGY LETTERS, VOL.16, NO.1, JANUARY1994
34, "Influence of External Optical Feedback o" described by Shijun Jiang et al.
n Threshhold and SpectralCharacteristics of Vertoc
al-Cavity Surface-Emitting Lasers "point out that when external reflected light returns to the surface-emitting semiconductor laser, the characteristics of the surface-emitting semiconductor laser change depending on the intensity of the returned light. That is, when an optical element (for example, a reflection scale) that gives strength to reflected light is disposed in the optical path of the emitted light, if the reflected light reflected from this optical element returns to the surface emitting semiconductor laser, the return light is harmful. There is a problem that the output of the surface-emitting semiconductor laser becomes unstable due to the occurrence of a serious interference.

Further, in the prior art 2, since many configurations (see FIG. 16) such as the semiconductor laser 16, the collimator lens 18, and the beam splitter 20 are required, not only the whole optical encoder becomes large, but also There is a problem that it takes time to assemble and adjust.

In the prior art 2, an optical encoder using a scale 22 having a diffraction grating 22a is shown. For example, a scale 22 having a high reflectance portion and a low reflectance portion alternately formed. An optical encoder that detects only the brightness of the image is also known as a known technique. In this known technique, the resolution of the optical encoder is reduced because the interval between the reflectance portions formed on the scale cannot be made too small, but the first and second techniques applied to the prior art 2 are reduced. Since the mirrors 24a and 24b are unnecessary, the size of the apparatus can be reduced. However, when an ordinary stripe-type semiconductor laser is used as the light source of this known technique, the collimator lens 18 is an essential member and cannot be omitted.

Accordingly, an object of the present invention is to provide a compact optical encoder having a high resolution, a low cost, and a simple configuration in order to solve such problems.

[0013]

In order to achieve the above object, an invention according to claim 1 is an optical encoder using a surface emitting semiconductor laser, wherein the optical encoder has a relative position with respect to the surface emitting semiconductor laser. And a light receiving element provided to receive reflected light or transmitted light from the scale when a part of the scale is irradiated by laser light emitted from the surface emitting semiconductor laser. The scale is provided with means for generating incoherent reflected light. The invention according to claim 2 is a scale moving relatively to the light source, a surface emitting semiconductor laser for irradiating a part of the scale, and a light receiving element for receiving reflected light or transmitted light from the scale. And a means for tilting the optical axis of light emitted from the surface emitting semiconductor laser. The invention according to claim 3 has a scale that moves relatively to the light source, a surface emitting semiconductor laser for irradiating a part of the scale, and a light receiving element for receiving light transmitted from the scale. In the encoder, light-shielding regions and light-transmitting regions are alternately arranged on the scale, and at least the light-shielding region is divided into a plurality of minute regions. There is a height difference (N; 0 or a positive integer) corresponding to the optical path length of {N + (1/4)} wavelength of the emitted light of the semiconductor laser.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of an optical encoder to which the present invention is applied will be described, and each embodiment of the present invention applied to this optical encoder will be described.

The optical encoder to which the embodiment of the present invention is applied is described in, for example, Japanese Patent Application No. 6-043656.
This will be described with reference to an optical encoder using a surface emitting semiconductor laser disclosed in the specification.

As shown in FIG. 1, the optical encoder includes a surface emitting semiconductor laser 32 provided in a recess 30 formed partially on a substrate 28, and a laser emitted from the surface emitting semiconductor laser 32. A light receiving element 36 mounted on the substrate 28 is provided so as to receive the reflected light reflected from the linear scale 34 irradiated by the light. The surface emitting semiconductor laser 32 is mounted on a slope 30a formed in the recess 30, and the linear scale 34 moves in the direction of arrow M in the figure.

According to this configuration, the surface emitting semiconductor laser 3
The laser light emitted from 2 is applied obliquely to the linear scale 34 moving in the direction of arrow M in the figure.
At this time, the laser light is reflected by the linear scale 34 and then received by the light receiving element 36. by the way,
Since the high-reflection areas 34a and the low-reflection areas 34b are alternately arranged on the linear scale 34, the amount of light received by the light receiving element 36 changes as the linear scale 34 moves. As a result, the output signal output from the light receiving element 36 varies. Accordingly, the linear scale 3 is obtained by electronically converting the strength of the output signal into a displacement amount of the scale or simply counting the strength of the signal.
4 can be detected.

According to such a configuration, a high resolution capability can be exhibited with a small number of parts and a simple configuration, so that a low-cost and small-sized optical encoder can be realized.

As another example of an optical encoder applied to the present invention, refer to another optical encoder using a surface emitting semiconductor laser disclosed in Japanese Patent Application No. 6-043656. explain. In the description of this example, the same components as those of the above-described configuration example are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 2, the optical encoder includes a substrate 40 disposed on a tilting table 38 at a predetermined angle and a surface emitting semiconductor laser mounted on a mounting surface 40a of the substrate 40. 32, and a light receiving element 36 mounted on the mounting surface 40a of the substrate 40 so as to receive the reflected light reflected from the linear scale 34 irradiated by the laser light emitted from the surface emitting semiconductor laser 32. ing.

The operation of such a configuration is the same as that of the above-described configuration example, and a description thereof will be omitted.

According to such a configuration, it is possible to obtain an effect that a step of forming a concave portion (see reference numeral 30 in FIG. 1) in the substrate 40 can be omitted. Note that other effects are the same as those of the above-described configuration example, and a description thereof will not be repeated.

The optical encoder shown in FIGS. 1 and 2 supports the surface emitting semiconductor laser 32 because the laser light emitted from the surface emitting semiconductor laser 32 needs to be obliquely incident on the scale 34. Substrates 28, 4
It is necessary to arrange a concave portion having a slope at a predetermined angle, an inclined pedestal having a predetermined angle, and the like on the zero. For this reason, not only the manufacturing process and the number of components increase, but also the process of assembling components on the inclined portion becomes more complicated than the process of assembling components on a horizontal plane. As a result, not only does the manufacturing and assembly cost increase, but it also hinders miniaturization of the device.

Further, since the surface emitting semiconductor laser 32 is arranged obliquely with respect to the scale 34, if the distance between the light emitting portion of the surface emitting semiconductor laser 32 and the scale 34 is shortened, the surface emitting semiconductor laser 32 Alternatively, there arises a problem that the corners of the substrates 28 and 40 supporting the surface emitting semiconductor laser 32 come into contact with the scale 34.

Normally, the output light of the surface emitting semiconductor laser 32 has a spread angle of about several degrees. Therefore, when the distance between the surface emitting semiconductor laser 32 and the scale 34 is increased, the output light is formed on the scale 34. The beam spot diameter increases. For this reason, it is necessary to set the pitch of the scale 34 large, and as a result, the resolution is reduced.

That is, when the beam spot diameter on the scale 34 is larger than the arrangement period of the high reflection area 34a and the low reflection area 34b in the scale 34, the plurality of high reflection areas 34a and the low reflection areas 34b are irradiated simultaneously. Will be. Therefore, the amount of light received by the light receiving element 36 is
Since the average value of the reflected light of each of the reflection areas 34a and 34b is close to the average value, the intensity of the amount of the reflected light generated from the moving scale 34 is hard to appear. Therefore, in order to realize a high-resolution optical encoder, the high-reflection area 34a and the low-reflection area 34b
It is necessary to reduce the arrangement period of the laser beam by a predetermined amount, to shorten the distance between the surface emitting semiconductor laser 32 and the scale 34, and to reduce the beam spot diameter on the scale 34 correspondingly.

However, no consideration is given to this point, and the distance between the light emitting portion of the surface emitting semiconductor laser 32 and the scale 34 is set relatively large. For this reason, the resolution of the optical encoder is limited.

In order to solve such a problem, it is desirable to arrange the surface emitting semiconductor laser 32 in parallel with the scale 34.

However, when the surface emitting semiconductor laser 32 is disposed in parallel to the scale 34, the reflected light reflected from the high reflection area or the light shielding area of the scale 34 returns to the surface emitting semiconductor laser 32 itself, as follows. Problems arise.

That is, the amount of reflected light changes with the movement of the scale 34, or a slight change in the distance between the scale 34 and the surface emitting semiconductor laser 32 causes
Because the interference state between the reflected light and the laser light changes,
A new problem arises in that the output of the surface emitting semiconductor laser 32 becomes unstable.

A description will now be given, with reference to FIG. 3, of a surface emitting semiconductor laser according to the first embodiment of the present invention, which has been improved to solve such a problem.

As shown in FIG. 3, the surface emitting semiconductor laser of the present embodiment has a semiconductor substrate 42 provided at the lower end thereof.
And an electrode 44 provided at the upper end thereof and having an emission window 44a for emitting laser light. An upper mirror 46 and a lower portion of the upper mirror 46 are formed between the semiconductor substrate 42 and the electrode 44.
A high resistance region 50 in which the active region 48 is arranged at a position aligned with the emission window 44a, and a lower mirror 52 formed below the high resistance region 50 are provided.

Further, in the surface emitting semiconductor laser of this embodiment, a quarter-wave plate 54 is bonded on the emission window 44a of the electrode 44.
6, a space as shown by a pair of arrows S is formed.

According to such a configuration, the current injected into the electrode 44 flows from the upper mirror 46 to the semiconductor substrate 42 via the active region 48 and the lower mirror 52.
At this time, the light emitted from the active region 48 is repeatedly reflected in the resonator constituted by the upper mirror 46 and the lower mirror 52. Then, a part of the light excited by such laser oscillation passes through the upper mirror 46 and is extracted as the laser light 56 from the emission window 44a.

The laser beam 56 (hereinafter, referred to as “outgoing light 56”) extracted from the outgoing window 44 a is linearly polarized light in the space indicated by the pair of arrows S, but transmits through the 波長 wavelength plate 54. After being converted into circularly polarized light,
The light is applied to an external optical element (not shown). Note that 1 /
The four-wavelength plate 54 is arranged so that its optical axis (generally, the crystal axis) forms an angle of 45 ° with the polarization direction of the light emitted from the surface emitting semiconductor laser.

The return light reflected from the optical element is circularly polarized light, but is converted into linearly polarized light by transmitting through the quarter-wave plate 54 again. The return light 56 'at this time is
Since the light is converted into linearly polarized light having a 90 ° polarization plane different from the polarization direction of the emitted light 56, no harmful interference occurs in the surface emitting semiconductor laser.

That is, according to the present embodiment, since the return light 56 'is configured so as not to adversely affect the surface emitting semiconductor laser, a surface emitting semiconductor laser having a high degree of freedom in the arrangement of the optical system can be used. The effect that it can be realized is obtained.

Further, the outgoing light 56 passes through the quarter-wave plate 54 from the space indicated by the pair of arrows S, and a part of the light is transmitted from the interface between the space and the quarter-wave plate 54. After being reflected, the light is returned again to the resonator (ie, the resonator constituted by the upper mirror 46 and the lower mirror 52).

The width of the space desirably has a dimension corresponding to the optical path length of {N + (1/2)} wavelength (N; 0 or a positive integer) of the emitted light 56. The round trip optical path length is equal to an integral multiple of the wavelength.

At this time, the phase of the reflected light reflected from the interface between the space and the quarter-wave plate 54 is the phase of the light in the resonator (ie, the resonator formed by the upper mirror 46 and the lower mirror 52). Becomes equal to

As a result, the laser oscillation efficiency can be further promoted.

As described above, according to the present embodiment, since the return light 56 'is configured not to adversely affect the surface emitting semiconductor laser, the surface emitting semiconductor laser having a high degree of freedom in the arrangement of the optical system is provided. Can be realized,
Laser oscillation efficiency can be further promoted.
Furthermore, according to the present embodiment, by joining the quarter-wave plate 54 on the electrode 44, it is possible to avoid the influence of non-uniformity at the joining portion and the refraction and scattering of light due to the inclusion of bubbles and the like. A new effect that can be obtained. The influence of refraction or scattering of light due to non-uniformity or mixing of air bubbles or the like at the joining portion may be caused by, for example, as shown in FIG. 5 described later, the joining layer 60 (for example, adhesive or the like) ) Means that there is an optical impairment due to the non-uniformity of the bonding layer or the inclusion of bubbles.

Therefore, by using the surface emitting semiconductor laser of the present embodiment having such effects, a compact optical encoder having a high resolution, a low cost, and a simple configuration can be realized.

Next, a surface emitting semiconductor laser according to a second embodiment of the present invention will be described with reference to FIGS. In the description of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

4 and 5 is a portion surrounded by a dotted line in the resonator 58 (ie, the upper mirror 46 and the lower mirror 52).
4, a dashed line A in FIG. 4 indicates a short axis of the emission window 44a, an arrow P indicates a polarization direction of the emission light 56,
Arrow C in FIG. 4 indicates the crystal axis direction of the １ ／ wavelength plate 54.

As shown in FIGS. 4 and 5, the 波長 wavelength plate 54 applied to the surface emitting semiconductor laser of this embodiment is used.
Are mounted on the bonding layer 60 provided in the emission window 44a of the electrode 44. Note that this bonding layer 60 is
It is desirable to have a thickness corresponding to an optical path length of {N + (1/2)} wavelength (N; 0 or a positive integer) of 6. Also,
The 波長 wavelength plate 54 is arranged such that its optical axis forms an angle of 45 ° with the plane of polarization of the emitted light.

In general, when the shape of the resonator 58 of the surface emitting semiconductor laser is anisotropic and the laser light is polarized in the direction of the short axis A of the resonator cross section, the emitted light 5
6 (see FIG. 3), the polarization direction P and the direction of the short axis A are parallel to each other. Therefore, the emission window 44a is made to have substantially the same shape as the resonator 58, and the quarter-wave plate 54 is arranged so that the crystal axis C is shifted by 45 ° with respect to the direction of the short axis A. As with the embodiment, the return light 56 'does not cause harmful interference in the surface emitting semiconductor laser.

The outgoing light 56 extracted from the outgoing window 44a passes through the quarter-wave plate 54 from the bonding layer 60 and is emitted to the outside.
After reflection from the interface of the ４ wavelength plate 54, the resonator 58
Is returned to.

By the way, the thickness of the bonding layer 60 is
In the case of having a size corresponding to an optical path length of {N + (1/2)} wavelength (N; 0 or a positive integer) of 6, the reciprocating optical path length is equal to an integral multiple of the wavelength.

At this time, the bonding layer 60 and the 波長 wavelength plate 54
The phase of the reflected light reflected from the interface with is equal to the phase of the light in the resonator 58.

As a result, the laser oscillation efficiency can be further promoted.

As described above, according to the present embodiment, in addition to the effects of the above-described first embodiment, the crystal axis of the quarter-wave plate 54 is further determined based on the shape of the emission window 44a during laser assembly. Since the direction C can be determined, a new effect that the assembly can be easily performed is obtained, and the phase of the light reflected from the interface between the bonding layer 60 and the 波長 wavelength plate 54 and the phase of the resonator 58 Since the light phase becomes equal, the laser oscillation efficiency can be further promoted. Therefore, by using the surface emitting semiconductor laser of the present embodiment having such effects, a compact optical encoder having a high resolution, a low cost, and a simple configuration can be realized.

In this embodiment, even if the crystal axis direction C of the quarter-wave plate 54 is set to a direction perpendicular to the direction shown in the plan view of FIG. To play.

Next, an optical encoder using a surface emitting semiconductor laser according to a third embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 6, the optical encoder according to the present embodiment has a scale (for example, a linear scale) 64 that moves relatively to the surface emitting semiconductor laser 62.
When a part of the scale 64 is irradiated with the laser light emitted from the surface emitting semiconductor laser 62, the scale 6
And a light receiving element 66 provided on the surface emitting semiconductor laser 62 so as to receive a part of the reflected light reflected from the light emitting element 4. The surface emitting semiconductor laser 62 is mounted on a substrate 76.

On the surface emitting semiconductor laser 62, 1
A 波長 wavelength plate 68 is mounted.
8 indicates that the crystal axis is 1/4 of that of the surface emitting semiconductor laser 62.
The laser light emitted to the wavelength plate 68 (hereinafter, the emitted light 70
a) is positioned so as to be shifted by 45 ° with respect to the polarization plane.

The light-receiving element 66 provided on the surface-emitting semiconductor laser 62 is positioned in a region where the light reflected from the scale 64 moving in the direction of arrow M in the figure can be received.

According to such a configuration, the linearly polarized outgoing light 70a emitted from the surface emitting semiconductor laser 32 becomes 1
The light is converted into a circularly-polarized light 70b by the あ る wavelength plate 68.

After the propagation light 70b reaches the scale 64 while spreading, it is reflected from the scale 64 to become reflected light as shown in FIG. The reflected light is indicated by reference numerals 72a, 72b, and 72c in FIG.

Some of the reflected light 72b, 72c
Does not return to the original optical path due to the spread of light, so only a part of the reflected light 72c reaches the light receiving element 66.

Since the scale 64 has the high reflection areas 64a and the low reflection areas 64b arranged alternately, the amount of light received by the light receiving element 66 changes as the scale 64 moves. As a result, the output signal output from the light receiving element 66 varies. Therefore, it is possible to detect the amount of movement of the scale 64 by counting the number of occurrences of the strength of the output signal.

On the other hand, the other reflected light 72 a returns to the surface-emitting semiconductor laser 62 after passing through the 波長 wavelength plate 68 again.

The other reflected light 72a is circularly polarized light, but is converted into return light 74 having linearly polarized light by transmitting through the quarter-wave plate 68 again. This return light 74
Is 90 ° different from the polarization plane of the outgoing light 70a, so that no harmful interference occurs in the surface emitting semiconductor laser 62.

As described above, according to the present embodiment, since the reflected light of the light radiated from the surface emitting semiconductor laser 62 to the scale 64 is directly received by the light receiving element 66, an optical device such as a collimator lens can be used. Parts are not required, and as a result, a low-cost and small-sized optical encoder with a small number of parts can be realized. Further, according to the present embodiment, the return light 74 is
The configuration in which no interference occurs in the inside makes it possible to arrange the scale 64 and the surface emitting semiconductor laser 62 face-to-face, thereby simplifying the assembling process of the device and increasing the degree of freedom in assembling. .

This embodiment can be modified as follows.

1. In the present embodiment, the light receiving element 66 is arranged on the same side of the scale 64 as the surface emitting semiconductor laser 62. However, for example, the scale 64 is configured as a transmission scale, and the light receiving element 66 is surface emitting with respect to the scale 64. It may be configured to be arranged on the opposite side of the semiconductor laser 62.

2. The light receiving element 66 may be formed on the surface emitting semiconductor laser 62 by a semiconductor process. In addition, as long as it can receive reflected light, it may be arranged on the substrate 76.

3. In the present embodiment, a linear scale is used as the scale 64, but a rotary scale may be used.

Next, an optical encoder using a surface emitting semiconductor laser according to a fourth embodiment of the present invention will be described with reference to FIG. In the description of this embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 7, the surface emitting semiconductor laser applied to the optical encoder of this embodiment is a dual emission type surface emitting semiconductor laser 62 ′
Are arranged on the substrate 76 side with respect to the surface emitting semiconductor laser 62 '. Further, between the surface emitting semiconductor laser 62 'and the light receiving element 66, the transmission axis thereof is 90 degrees with respect to the polarization plane of the laser light emitted from the surface emitting semiconductor laser 62'.
A polarization filter 78 shifted by ° is interposed.

According to such a configuration, of the laser light emitted from the surface emitting semiconductor laser 62 ′, the linearly polarized upward emission light 80 a emitted in the scale 64 direction is
After being converted into a propagating light 82 having circular polarization by the 波長 wavelength plate 68, the light reaches the scale 64.

At this time, the reflected light 84 reflected from the scale 64 is transmitted through the quarter-wave plate 68 again, so that it has a linearly polarized light having a 90 ° polarization plane different from the polarization plane of the upper outgoing light 80a. After being converted into the return light 86, the light passes through the polarizing filter 78 from the surface emitting semiconductor laser 62 ′ and reaches the light receiving element 66.

On the other hand, of the laser light emitted from the surface emitting semiconductor laser 62 ′, the downward emission light 80 b emitted toward the light receiving element 66 has a polarization plane shifted by 90 ° with respect to the transmission axis of the polarization filter 78. Because it is linearly polarized light,
It cannot pass through the polarizing filter 78.

As described above, according to the present embodiment, the following effects can be obtained in addition to the effects of the third embodiment.
That is, in the present embodiment, when the light is guided to the light receiving element 66, the effect of the spread of the upper emission light 80a is not required, so that the scale 64 and the dual emission type surface emitting semiconductor laser 6 are used.
The distance between 2 ′ and １ ／ wavelength plate 68 and scale 64
Can be as close as possible without contact.
As a result, the beam diameter for irradiating the scale 64 can be reduced, and high resolution can be achieved.

Further, according to the present embodiment, the light receiving element 6
6, only the reflected light 84 reflected from the scale 64 is taken in, so that high detection sensitivity can be maintained.

In this embodiment, for example, a polarizing prism may be used instead of the polarizing filter 78.

Next, an optical encoder using a surface emitting semiconductor laser according to a fifth embodiment of the present invention will be described with reference to FIG. In the description of this embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 8, the optical encoder according to the present embodiment has a scale 64 that moves relatively to a surface-emitting semiconductor laser 62 and a scale that is driven by laser light emitted from the surface-emitting semiconductor laser 62. A light receiving element 66 provided on the surface emitting semiconductor laser 62 is provided so as to receive a part of the reflected light reflected from the scale 64 when a part of the scale 64 is irradiated. Means for generating a strong reflected light is provided.

Scale 64 applied to the present embodiment
Is frosted glass with aluminum deposited on its surface
The means for generating incoherent reflected light include the high scattering region 64a and the low scattering region 64b obtained by partially blackening aluminum.

According to such a configuration, when laser light is irradiated from the surface emitting semiconductor laser 62 onto the scale 64, incoherent reflected light, that is, scattered reflected light from the high scattering region 64 a and the low scattering region 64 b of the scale 64. Light is generated.

At this time, since a part of the scattered reflected light is received by the light receiving element 66, a change in the intensity of the scattered reflected light caused by the movement of the scale 64 is detected.

As described above, according to the present embodiment, the following effects can be obtained.

That is, since the laser light applied to the scale 64 is scattered and reflected by the high scattering area 64a and the low scattering area 64b, coherent reflected light returning to the surface emitting semiconductor laser 62 is not generated. As a result, a stable output can be obtained without causing harmful interference to the surface emitting semiconductor laser.
2 can be arranged in parallel with each other, the assembling process of the device can be simplified, and the degree of freedom in assembling can be increased.

Further, according to the present embodiment, the scale 6
The distance between the surface emitting semiconductor laser 4 and the surface emitting semiconductor laser 62 can be reduced to the utmost limit as long as the light receiving element 66 and the scale 64 do not contact each other. As a result, the beam diameter for irradiating the scale 64 can be reduced, and high resolution can be achieved.

The present embodiment can be modified as follows.

1. In the present embodiment, the light receiving element 66 is arranged on the same side of the scale 64 as the surface emitting semiconductor laser 62. However, for example, the scale 64 is configured as a transmission scale, and the light receiving element 66 is surface emitting with respect to the scale 64. It may be configured to be arranged on the opposite side of the semiconductor laser 62. In this case, a metal film may be partially formed on the transmission scale, for example, on frosted glass, and the light-shielding portions and the transmission portions may be alternately arranged.

2. The light receiving element 66 may be formed on the surface emitting semiconductor laser 62 by a semiconductor process. In addition, as long as the position can receive the scattered reflected light, it may be arranged on the substrate 76.

3. In the present embodiment, a linear scale is used as the scale 64, but a rotary scale may be used.

Next, an optical encoder using a surface emitting semiconductor laser according to a sixth embodiment of the present invention will be described with reference to FIG. In the description of this embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 9, a scale 64 applied to the optical encoder according to the present embodiment has
a and the light-transmitting portions 64b are formed alternately. The light-shielding portions 64a and the light-transmitting portions 64b are formed by, for example, partially frosting the glass surface and depositing a metal thin film on these printed vitrified portions. Is formed. In this case, it is preferable to apply an anti-reflection coating on the surface of the light transmitting portion 64b.

The light receiving element 66 applied to the present embodiment is a
And on the opposite side.

According to such a configuration, the laser light emitted from the surface emitting semiconductor laser 62 is applied to the scale 64, but the laser light applied to the light shielding portion 64a is scattered and reflected.

That is, by being scattered and reflected, coherent reflected light which returns to the surface emitting semiconductor laser 62 and causes harmful interference is not generated.

On the other hand, the laser beam applied to the light transmitting portion 64b is transmitted through the scale 64 without being scattered, and then received by the light receiving element 66.

As a result, based on the electric signal corresponding to the change in the amount of received light output from the light receiving element 66, the scale 6
4 is detected.

As described above, according to the present embodiment, the following effects can be obtained in addition to the effects of the fifth embodiment.
That is, since light that does not scatter is irradiated on the light receiving element 66,
A new effect of increasing the amount of received light and improving the S / N ratio is obtained.

Next, an optical encoder using a surface emitting semiconductor laser according to a seventh embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 10, the optical encoder of this embodiment includes a prism 88 formed directly on a surface emitting semiconductor laser 62 by a semiconductor manufacturing process. According to such a configuration, the emission light 90a emitted from the surface emitting semiconductor laser 62 in the direction of the prism 88.
After being deflected through the prism 88, the light becomes the propagation light 90b and is obliquely applied to the scale 64.

At this time, the reflected light 90c reflected from the scale 64 is received by the light receiving element 66, and the intensity of the light is detected. As a result, the movement amount of the scale 64 is detected.

According to the present embodiment, the following effects can be obtained. That is, by irradiating the propagation light 90b obliquely to the scale 64, the scale 6
The reflected light 90c reflected from the surface emitting semiconductor laser 62 is
Returning to is avoided. As a result, the scale 64 and the surface-emitting semiconductor laser 62 can be arranged in parallel to each other, so that the assembling process of the device can be simplified and the degree of freedom in assembling can be increased.

Furthermore, according to the present embodiment, since the prism 88 directly formed by the semiconductor manufacturing process is disposed on the surface emitting semiconductor laser 62, no external optical components are required, and the assembly process can be simplified. The effect that can be obtained.

This embodiment can be modified as follows.

1. In the present embodiment, the light receiving element 66 is arranged on the same side of the scale 64 as the surface emitting semiconductor laser 62. However, for example, the scale 64 is configured as a transmission scale, and the light receiving element 66 is surface emitting with respect to the scale 64. It may be configured to be arranged on the opposite side of the semiconductor laser 62.

2. The light receiving element 66 may be formed on the surface emitting semiconductor laser 62 by a semiconductor process. In addition, as long as it can receive reflected light, it may be arranged on the substrate 76.

3. In the present embodiment, a linear scale is used as the scale 64, but a rotary scale may be used.

4. In the present embodiment, the prism 88 formed directly on the surface emitting semiconductor laser 62 by the semiconductor manufacturing process is used, but an optical component manufactured separately may be attached.

Next, an optical encoder using a surface emitting semiconductor laser according to an eighth embodiment of the present invention will be described with reference to FIG. In the description of this embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 11, the scale 64 applied to the present embodiment has a plurality of first inclined surface regions 64a.
And a plurality of second inclined surface regions 64b are formed alternately. These first and second inclined surface regions 64a, 64b
By applying the photolithographic technique and the anisotropic etching technique to the scale 64 made of a silicon substrate, it can be manufactured with low cost and high accuracy.

According to such a configuration, of the laser light emitted from the surface emitting semiconductor laser 62 in the direction of the scale 64, the laser light applied to the first inclined surface region 64a is reflected from the inclined surface region 64a. After that, the light receiving element 6
6 is received.

On the other hand, if it is assumed that the laser light is applied to the second inclined surface region 64b by the movement of the scale 64 (not shown), the reflected light from the second inclined surface region 64b Since the light is reflected in different directions, it does not reach the light receiving element 66.

As a result, only the reflected light reflected from the first inclined surface area 64a is received by the light receiving element 66 with the movement of the scale 64, and the amount of movement of the scale 64 is determined based on the intensity of the received light. Will be detected.

As described above, according to the present embodiment, the following effects can be obtained. That is, since there is no return light in the direction of the surface emitting semiconductor laser 62, the scale 64 and the surface emitting semiconductor laser 62 can be arranged in parallel with each other. As a result, the assembling process of the device can be simplified and the degree of freedom of assembling can be increased.

Further, according to the present embodiment, the scale 64 having the first inclined surface region 64a manufactured using the silicon substrate as a material and using the photolithographic technique and the anisotropic etching technique is used. Since the manufacturing process can be simplified, there is obtained an effect that a low-cost and high-precision optical encoder can be realized.

This embodiment can be modified as follows.

1. In the present embodiment, the light receiving element 66 is arranged on the same side of the scale 64 as the surface emitting semiconductor laser 62. However, for example, the scale 64 is configured as a transmission scale, and the light receiving element 66 is surface emitting with respect to the scale 64. It may be configured to be arranged on the opposite side of the semiconductor laser 62. In this case, the light receiving element 66 is arranged at a position that receives only light that is refracted and transmitted from the first inclined region 64a and does not receive light that is transmitted through other regions.

[0116] 2. The light receiving element 66 may be formed on the surface emitting semiconductor laser 62 by a semiconductor process. In addition, as long as it can receive reflected light, it may be arranged on the substrate 76.

3. In the present embodiment, a linear scale is used as the scale 64, but a rotary scale may be used.

Next, an optical encoder using a surface emitting semiconductor laser according to a ninth embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 12, a scale 64 applied to the present embodiment is formed of a material such as glass, and such a scale 64 is formed by metal deposition on a V-groove-shaped inclined surface region. A light-shielding portion 64a formed by applying a film or the like and a light-transmitting portion 64b having an antireflection film applied to a surface other than the light-shielding portion 64a are provided alternately.

In the present embodiment, the light receiving element 6
Numeral 6 is disposed on the opposite side of the scale 64 from the surface emitting semiconductor laser 62.

According to such a configuration, of the laser light emitted from the surface emitting semiconductor laser 62, the light transmitting portion 64
The laser light applied to the portion b is transmitted through the transmitting portion 64b.
, And is received by the light receiving element 66. On the other hand, the movement of the scale 64 causes the light shielding portion 64 to move.
The laser light applied to the portion a of FIG.
Is reflected in the directions of arrows R1 and R2 in FIG.
Does not reach.

As a result, only the laser beam transmitted through the light transmitting portion 64b is transmitted by the light receiving element 6 with the movement of the scale 64.
6, the amount of movement of the scale 64 is detected based on the intensity of the amount of received light.

As described above, according to the present embodiment, the following effects can be obtained in addition to the effects of the eighth embodiment.
That is, since only the laser beam that has passed straight through the scale 64 and is detected is detected, for example, as shown in the eighth embodiment, the light receiving element 66 is configured to receive the reflected light reflected from the scale 64. A new effect is achieved in that the step of adjusting the position with high accuracy, the adjustment, and the like become unnecessary.

Next, an optical encoder using a surface emitting semiconductor laser according to a tenth embodiment of the present invention will be described with reference to FIG. In the description of this embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 13A, the scale 64 applied to the present embodiment is formed of a material such as glass, and such a scale 64 is provided with a metal deposition film or the like. Light-shielding portions 64a and light-transmitting portions 64b that transmit laser light are formed alternately.

As shown in FIG. 13B, the light shielding portion 64a
Of the micro regions 92a, 9 having relatively different heights.
2b, and these minute regions 92a, 92b
(The height difference indicated by arrow D in the figure) is １ ／ of the wavelength.
Stipulated. Similarly, minute regions 94a and 94b having relatively different heights are provided on the surface of the light transmitting portion 64b, and the height difference between these minute regions 94a and 94b (the height difference indicated by an arrow D in the drawing). ) Is defined as １ ／ of the wavelength.

In the present embodiment, the light receiving element 6
Numeral 6 is disposed on the opposite side of the scale 64 from the surface emitting semiconductor laser 62.

According to such a configuration, the laser beam 96 emitted from the surface emitting semiconductor laser 62 is
(Ie, the amount of light received by the light receiving element 66)
Since it changes with the movement of the scale 64, the light receiving element 6
The amount of movement of the scale 64 can be detected by detecting the amount of received light of No. 6.

More specifically, as shown in FIG.
The laser beam 9 applied to the light transmitting portion 64b of the scale 64
6 indicates that a part of the light is transmitted through the minute regions 94a, 94a,
94b.

The reflected light 98a, 98b generated at this time
Are 互 い に each other due to the optical path difference corresponding to the height difference D.
It has a periodic phase difference. As a result, the reflected lights 98a, 98
b will cancel each other out.

Similarly, the reflected light reflected from the light shielding portion 64a also cancels out each other.

As described above, since the reflected lights cancel each other, no harmful interference occurs in the surface emitting semiconductor laser 62.

As described above, according to the present embodiment, the following effects can be obtained. That is, since no reflected light is generated in the direction of the surface emitting semiconductor laser 62, the scale 64 and the surface emitting semiconductor laser 62 can be arranged in parallel with each other. As a result, the assembling process of the device can be simplified and the degree of freedom of assembling can be increased. Furthermore, scale 64
And the surface emitting semiconductor laser 62 can be brought close to each other, so that the beam diameter for irradiating the scale 64 can be reduced,
Higher resolution can be achieved.

Next, an optical encoder using a surface emitting semiconductor laser according to an eleventh embodiment of the present invention will be described with reference to FIG. In the description of this embodiment, the same components as those of the third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 14, the scale 64 applied to the present embodiment is formed of a material such as glass, and the scale 64 has a plurality of periodically provided diffraction grating regions. 64a and other translucent regions 64b
Are provided alternately.

Each of the diffraction grating regions 64a is constituted by a blazed grating that strongly generates only the + 1st-order diffracted light 102. In addition, a non-reflective film is applied to the light transmitting region 64b.

The light receiving element 66 has a diffraction grating region 64.
a to receive the + 1st-order diffracted light 102 generated from
It is mounted on a surface emitting semiconductor laser 62.

According to such a configuration, of the laser light 100 emitted from the surface-emitting semiconductor laser 62, the laser light 100 applied to the diffraction grating region 64a of the scale 64 is emitted from the diffraction grating region 64a. After being diffracted as + 1st-order diffracted light 102, it is received by the light receiving element 66. At this time, no return light is reflected from the scale 64 toward the surface emitting semiconductor laser 62.

When the scale 64 moves and the laser beam 100 falls outside the diffraction grating region 64a and irradiates the light transmitting region 64b, the laser beam 10
Since 0 transmits through the scale 64, no + 1st-order diffracted light 102 is generated from the scale 64. As a result, the light is not irradiated on the light receiving element 66.

As described above, only the + 1st-order diffracted light 102 generated from the diffraction grating region 64a is received by the light receiving element 66 with the movement of the scale 64, and the amount of movement of the scale 64 is determined based on the intensity of the received light. Will be detected.

As described above, according to the present embodiment, the following effects can be obtained. That is, since return light in the direction of the surface emitting semiconductor laser 62 does not occur, the surface emitting semiconductor laser 6
No harmful interference will occur in 2. As a result, the scale 64 and the surface-emitting semiconductor laser 62 can be arranged in parallel to each other, so that the assembling process of the device can be simplified and the degree of freedom in assembling can be increased. Further, since the scale 64 and the surface-emitting semiconductor laser 62 can be brought close to each other, the diameter of the beam irradiated on the scale 64 can be reduced, and high resolution can be achieved.

A technical idea having the following configuration is derived from each of the above specific embodiments.

(1) A surface-emitting semiconductor laser having a front surface and a back surface, wherein the surface-emitting semiconductor laser has an emission window for emitting laser light, which is disposed on at least one of the front surface and the back surface, and a crystal axis thereof. And a quarter-wave plate disposed on the emission window so that the light is shifted by 45 ° with respect to the polarization plane of the emitted light emitted from the surface-emitting semiconductor laser. Semiconductor laser.

(Structure) The present invention corresponds to the first embodiment (see FIG. 3). The emission window is the same as that of the fourth embodiment.
4a corresponds to this. The 波長 wavelength plate is a birefringent optical element that produces a phase difference of 90 ° between two orthogonal polarization planes, and corresponds to 54 in the embodiment.

(Operation) The outgoing light 56 emitted from the outgoing window 44a is linearly polarized light. The outgoing light 56 is converted into circularly polarized light by passing through the quarter-wave plate 54, and is extracted outside. When the return light 56 'follows the reverse path of the output light 56, the circularly polarized return light 56' is converted by the quarter-wave plate 54 into a linearly polarized return light 56 having a 90 ° polarization plane different from that of the original output light 56. , No harmful interference that would make the output of the surface emitting semiconductor laser unstable would occur.

(Effect) Since return light from an external optical element or the like does not adversely affect the surface emitting semiconductor laser, a surface emitting semiconductor laser in which an optical system can be freely arranged without considering the influence is obtained. be able to.

(2) A vertical resonator (58) having a non-isotropic planar shape, an emission window (44a) having a planar shape substantially the same as the vertical resonator, and a １ ／ wavelength plate (5
The crystal axis of 4) is shifted by 4 with respect to the short axis (A) direction of the exit window.
The surface-emitting semiconductor laser according to (1), wherein the semiconductor laser is arranged at a position shifted by 5 °.

(Structure) The present invention corresponds to the second embodiment (see FIGS. 4 and 5). The above-described resonator corresponds to the embodiment 58, but also includes a case where the planar shape is an ellipse or an ellipse.

(Operation) In general, when the cavity of a surface emitting semiconductor laser is anisotropic, the plane of polarization of the emitted light is parallel to the minor axis direction of the cavity. Therefore, the same operation as (1) can be obtained by making the exit window substantially the same shape as the resonator and disposing the crystal axis of the １ ／ wavelength plate by 45 ° with respect to the short axis direction of the exit window. .

(Effect) Since the crystal axis direction of the １ ／ wavelength plate can be determined by the shape of the exit window at the time of assembling, a new effect that the assembling becomes easy is obtained.

(3) The 波長 wavelength plate (54) is a bonding layer (60) having a thickness corresponding to the optical path length of {N + (１ ／)} wavelength (N is 0 or a positive integer) of the emitted light. The surface-emitting semiconductor laser according to (1), wherein the surface-emitting semiconductor laser is joined to the emission window via a through hole.

(Structure) The present invention corresponds to the second embodiment (see FIGS. 4 and 5). The bonding layer corresponds to 60 in the embodiment.

(Function) The light emitted from the emission window 44a passes through the bonding layer 60 and the quarter-wave plate 54 and is extracted to the outside. The light is reflected at the interface and returns to the resonator 58. At this time, since the thickness of the bonding layer 60 is equivalent to the optical path length of {N + (1/2)} wavelength (N; 0 or a positive integer) of the emitted light, the reciprocating optical path length is equal to the wavelength. It becomes equal to an integer multiple. Therefore, the bonding layer 60
The phase of the reflected light at the interface between the
8 is equal to the phase of the light.

(Effect) Since the phase of the reflected light at the interface between the bonding layer 60 and the quarter-wave plate 54 is equal to the phase of the light in the resonator 58, the light in the resonator 58 is strengthened and the laser oscillation is reduced. This has the effect of further accelerating.

(4) Quarter-wave plate (54) bonded on the electrode and thickness corresponding to the optical path length of {N + (1/2)} wavelength (N; 0 or a positive integer) of emitted light The surface emitting semiconductor laser according to (1), further comprising a space (S) between the １ ／ wavelength plate and the emission window.

(Structure) The present invention corresponds to the first embodiment (see FIG. 3). The space corresponds to the portion indicated by the arrow S.

(Effect) Outgoing light 56 emitted from the outgoing window 44a
Is transmitted through the space S and the 波長 wavelength plate 54 and is extracted to the outside, but a part of the light is reflected at the interface between the space S and the 波長 wavelength plate 54 and is reflected by the resonator (ie, the upper mirror 46 and the lower mirror). 5
2). At this time, the space S
Is a thickness corresponding to the optical path length of {N + (1/2)} wavelength (N; 0 or a positive integer) of the outgoing light, so that the reciprocating optical path length is equal to an integral multiple of the wavelength. Therefore, the phase of the reflected light at the interface between the space S and the quarter-wave plate 54 becomes equal to the phase of the light in the resonator.

(Effect) The same effect as the above (3) can be obtained, and since the quarter-wave plate (54) is bonded on the electrode, the light due to the non-uniformity of the bonding layer and the mixing of bubbles and the like can be obtained. A new effect of not being affected by refraction, scattering, and the like is obtained. In addition, the influence of refraction or scattering of light due to non-uniformity or mixing of air bubbles or the like in the bonding portion is, for example, as shown in FIG. 5, the bonding layer 60 (for example, an adhesive or the like) on the exit window. Means that there is an optical obstacle due to the non-uniformity of the bonding layer and the inclusion of air bubbles.

(5) An optical encoder using the surface emitting semiconductor laser according to the above (1), wherein the scale moves relatively to the surface emitting semiconductor laser, and the scale is emitted from the surface emitting semiconductor laser. When irradiating a part of the scale with the laser light, a light receiving element provided in the surface emitting semiconductor laser so as to receive reflected light or transmitted light generated from the scale. Optical encoder.

(Structure) The present invention corresponds to the third embodiment (see FIG. 6). The surface emitting semiconductor laser is the surface emitting semiconductor laser of (1), and
Is applicable. The light receiving element is a photoelectric conversion element such as a photodiode, and corresponds to 66 in the embodiment. The scale is one in which a high reflectance area and a low reflectance area are periodically arranged on the surface of a glass plate or the like, and corresponds to 64 of the embodiment, but includes a rotary encoder scale or the like used when detecting rotational movement. . In addition, instead of areas with high and low reflectivity, light-shielding parts and light-transmitting parts are periodically arranged, and light-receiving elements are arranged on the opposite side of the scale from the surface-emitting semiconductor laser to detect transmitted light on the scale. It is good also as composition which performs.

(Function) The linearly polarized light emitted from the surface emitting semiconductor laser 62 is converted into circularly polarized light by the 板 wavelength plate 68 and is irradiated on the scale 64. The expanded part of the reflected light from the scale 64 is received by the light receiving element 66. Also, the reflected light returning from the scale 64 to the surface emitting semiconductor laser 62 is separated from the original emitted light by 90 ° by the 波長 wavelength plate 68.
Since the linearly polarized light has different polarization planes, harmful interference that makes the output of the surface emitting semiconductor laser 62 unstable does not occur.

(Effect) The scale 64 and the surface-emitting semiconductor laser 62 can be arranged in parallel because the return light does not cause interference to the surface-emitting semiconductor laser 62. This has an effect that the assembly of the device can be omitted.

(6) The surface emitting semiconductor laser of the above (1) is a dual emission type surface emitting semiconductor laser (62 '),
The light receiving element is a light receiving element (66) for receiving the reflected light from the scale (64), and the light receiving element is arranged on a side opposite to the scale with respect to the surface emitting semiconductor laser, A polarizing filter (78) arranged between the surface emitting semiconductor laser and the light receiving element and having its transmission axis shifted by 90 ° with respect to the polarization plane of the emitted light (80a, 80b) from the surface emitting semiconductor laser; (5) The optical encoder according to (5). (Structure) The present invention corresponds to the fourth embodiment (see FIG. 7). The surface emitting semiconductor laser is the semiconductor laser according to the above (1), and has a light emitting window on both sides.
2 'corresponds. The polarizing filter is, for example, an optical element such as a polymer polarizing film that transmits linearly polarized light having a specific polarization plane, and corresponds to the embodiment 78, but also includes a polarizing prism and the like.

(Function) Dual emission type surface emitting semiconductor laser 6
Reference numeral 2 'denotes light emitted from the light emission windows on both surfaces, and reflected light 8 from the scale 64 incident from one light emission window.
4, 86 are transmitted to the other. The polarizing filter 78 outputs the lower emission light 80b of the dual emission type surface emitting semiconductor laser 62 '.
And the return light 86 from the scale 64 is transmitted. Therefore, the light receiving element 66 receives only the reflected light from the scale 64.

(Effect) In addition to the effect of the above (5), the distance between the scale 64 and the dual emission type surface emitting semiconductor laser 62 'is reduced to the limit (as long as the quarter wavelength plate 68 does not contact the scale 64). Scale 6
4 can be reduced in beam diameter, and high resolution can be achieved.

(7) An optical encoder using a surface-emitting semiconductor laser, wherein the scale moves relative to the surface-emitting semiconductor laser and the scale is moved by laser light emitted from the surface-emitting semiconductor laser. A light receiving element provided to receive reflected light or transmitted light generated from the scale when a part of the scale is irradiated, and the scale is provided with means for generating incoherent reflected light. An optical encoder characterized in that:

(Structure) The present invention corresponds to the fifth embodiment (see FIG. 8). The scale is provided with a high scattering region 64a and a low scattering region 64b that generate incoherent reflected light by partially blackening frosted glass on which aluminum is deposited on the surface, for example. However, a reflecting portion and a light transmitting portion may be provided instead of the high scattering region and the low scattering region. In addition, a light blocking portion and a light transmitting portion may be provided instead of the high scattering region and the low scattering region, and the light receiving element may be configured to detect the transmitted light. Note that "producing incoherent reflected light" means that reflected light is generated as scattered reflected light.

(Operation) The laser light emitted from the surface emitting semiconductor laser 62 is irradiated on the scale 64. Part of the light scattered by the scale 64 is received by the light receiving element 66. At this time, the movement of the scale 64 is detected based on the intensity of the scattered light caused by the movement of the scale 64.

(Effect) In this configuration, since coherent reflected light from the scale 64 to the surface emitting semiconductor laser 62 does not occur, harmful interference due to return light to the surface emitting semiconductor laser does not occur. Further, since the distance between the scale 64 and the surface emitting semiconductor laser 62 can be reduced, the beam diameter for irradiating the scale 64 can be reduced, and high resolution can be achieved.

(8) The scale is a scale (64) in which light-shielding portions (64a) and light-transmitting portions (64b) are periodically arranged, and the light-receiving element receives light transmitted from the scale. 66) The optical encoder according to (7), wherein the light-shielding portion of the scale is provided with a unit having a property of generating incoherent reflected light.

(Structure) The present invention corresponds to the sixth embodiment (see FIG. 9). The light shielding portion is 64 in the embodiment.
The light transmitting portion corresponds to 64b of the embodiment.

(Operation) The laser beam emitted from the surface emitting semiconductor laser 62 is applied to the scale 64. When the laser light is applied to the light shielding portion 64a, the light is scattered and does not reach the light receiving element 66. In addition, coherent reflected light that returns to the surface emitting semiconductor laser 62 and causes harmful interference does not occur. On the other hand, the laser light applied to the light transmitting portion 64b is transmitted through the scale 64 and then received by the light receiving element 66. Thus, the amount of movement of the scale 64 is detected based on the change in the amount of light received by the light receiving element 66.

(Effect) In addition to the effect of the above (7), since directly transmitted light not scattered by the light receiving element 66 is received, the amount of received light increases, and as a result, the S / N ratio is improved. Get new.

(9) A scale (64) that moves relatively to a light source, a surface-emitting semiconductor laser (62) for irradiating a part of the scale, and light reflected or transmitted from the scale is received. An optical encoder comprising: a light receiving element (66) for performing the above operation; and a means (88) for inclining an optical axis of light emitted from the surface emitting semiconductor laser.

(Structure) The present invention corresponds to the seventh embodiment (see FIG. 10). The means for tilting the optical axis of the emitted light corresponds to the prism 88 in the embodiment, but also includes a diffraction grating and the like.

(Function) The emitted light 90a from the surface emitting semiconductor laser 62 is obliquely incident on the scale 64 by means for tilting the optical axis, that is, the prism 88, and the reflected light is received by the light receiving element 66.

(Effect) In this configuration, since reflected light from the scale 64 does not return to the surface emitting semiconductor laser 62, no harmful interference occurs even if the scale 64 and the surface emitting semiconductor laser 62 are arranged in parallel. In addition, since the distance between the scale and the surface emitting semiconductor laser can be reduced, the beam diameter for irradiating the scale can be reduced, and high resolution can be achieved.

(10) A scale (64) that moves relatively to a light source, a surface-emitting semiconductor laser (62) for irradiating a part of the scale, and a light reflected or transmitted from the scale. Light receiving element for receiving light (66)
Wherein the scale has a plurality of periodic inclined surface areas (64a, 64b).

(Structure) The present invention corresponds to the eighth embodiment (see FIG. 11). In the embodiment, the inclined surface regions correspond to 64a and 64b.

(Operation) The laser light emitted from the surface emitting semiconductor laser 62 is applied to the first inclined surface area 64 of the scale 64.
When the light is irradiated on the light receiving element a, the light reflected from the first inclined surface area 64a is received by the light receiving element 66. When the scale moves and a portion other than the first inclined surface region 64a (for example, the second inclined surface region 64b) is irradiated,
The reflected light does not reach the light receiving element 66. Therefore, the movement amount of the scale is detected based on the intensity of the light reception amount of the light receiving element 66 which changes with the movement of the scale.

(Effect) Since the reflected light from the scale 64 does not return to the surface emitting semiconductor laser 62, harmful interference does not occur. In addition, since the distance between the scale and the surface emitting semiconductor laser can be reduced, the beam diameter for irradiating the scale can be reduced, and high resolution can be achieved.

(11) The scale is a scale in which a light shielding part (64a) and a light transmitting part (64b) are periodically arranged.
The optical encoder according to (10), wherein the light receiving element is a light receiving element (66) for receiving the transmitted light from the scale, and an inclined surface area of the scale is disposed in the light shielding portion.

(Structure) The present invention corresponds to the ninth embodiment (see FIG. 12). The light shielding portion and the light transmitting portion correspond to 64a and 64b in the embodiment.

(Operation) When the light emitted from the surface emitting semiconductor laser is applied to the light shielding portion, the light is reflected in a direction different from that of the surface emitting semiconductor laser and the light receiving element. When the emitted light irradiates the light transmitting portion, it passes through the scale and is received by the light receiving element.

(Effect) In addition to the effect of the above (10), since the transmitted light is detected by the light receiving element, the position of the reflected light does not need to coincide with the position of the light receiving element, and no adjustment is required. The effect is obtained.

(12) A scale (64) that moves relatively to a light source, a surface-emitting semiconductor laser (62) for irradiating a part of the scale, and a device for receiving transmitted light from the scale In the encoder having the light receiving element (66), the scale includes a light shielding area (64).
a) and the light-transmitting region (64b) are alternately arranged;
Further, at least the light-shielding region includes a plurality of minute regions (9
2a, 92b, 94a, and 94b), and a height (N; equivalent to the optical path length of {N + (1/4)} wavelength of the emitted light of the surface emitting semiconductor laser is provided between each minute region.
An optical encoder having a height difference (D) of 0 or a positive integer.

(Structure) The present invention corresponds to the tenth embodiment (see FIG. 13). In the embodiment, the minute regions correspond to 92a, 92b, 94a, and 94b, respectively.

(Operation) The reflected lights 98a and 98b generated on the surface of the scale 64 have a phase difference of 周期 cycle caused by an optical path difference due to the step D, and therefore cancel each other.

(Effect) Since the reflected lights cancel each other, harmful interference to the surface emitting semiconductor laser 62 due to the return light does not occur. In addition, since the distance between the scale and the surface emitting semiconductor laser can be reduced, the beam diameter for irradiating the scale can be reduced, and high resolution can be achieved.

(13) A scale (64) that moves relatively to a light source, a surface-emitting semiconductor laser (62) for irradiating a part of this scale, and a first-order or higher-order laser beam from the scale. An optical encoder having a light receiving element (66) for receiving diffracted light, wherein the scale has a plurality of periodic diffraction grating regions (64a).

(Structure) The present invention corresponds to the eleventh embodiment (see FIG. 14). The diffraction grating region corresponds to 64a of the embodiment. In this diffraction grating region, it is desirable to use a blazed grating having a diffraction characteristic that does not generate zero-order diffracted light.

(Operation) The diffracted light 102 generated from the diffraction grating region 64a is received by the light receiving element 66. When the scale moves and a portion other than the diffraction grating region 64a is irradiated, no diffracted light is generated. Therefore, the amount of movement of the stage is detected based on the intensity of the amount of light received by the light receiving element 66 caused by the movement of the scale.

(Effect) Since the reflected light from the scale 64 does not return to the surface emitting semiconductor laser 62, harmful interference does not occur. In addition, since the distance between the scale and the surface emitting semiconductor laser can be reduced, the beam diameter for irradiating the scale can be reduced, and high resolution can be achieved.

[0194]

According to the present invention, a compact optical encoder having a high resolution, a low cost, and a simple configuration can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of an optical encoder according to the principle of the present invention.

FIG. 2 is a diagram schematically showing a configuration of an optical encoder according to another principle of the present invention.

FIG. 3 is a diagram schematically showing a configuration of a surface emitting semiconductor laser according to the first embodiment of the present invention.

FIG. 4 is a top view showing a configuration of a surface emitting semiconductor laser according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a configuration of a surface emitting semiconductor laser according to a second embodiment of the present invention.

FIG. 6 is a diagram schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to a third embodiment of the present invention.

FIG. 7 is a diagram schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to a fourth embodiment of the present invention.

FIG. 8 is a diagram schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to a fifth embodiment of the present invention.

FIG. 9 is a diagram schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to a sixth embodiment of the present invention.

FIG. 10 is a diagram schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to a seventh embodiment of the present invention.

FIG. 11 is a diagram schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to an eighth embodiment of the present invention.

FIG. 12 is a view schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to a ninth embodiment of the present invention.

FIG. 13A is a diagram schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to a tenth embodiment of the present invention, and FIG. 13B is applied to the present embodiment. The figure which expands and shows a part of scale made.

FIG. 14 is a view schematically showing a configuration of an optical encoder using a surface emitting semiconductor laser according to an eleventh embodiment of the present invention.

FIG. 15 is a diagram schematically showing a configuration of a conventional surface emitting semiconductor laser.

FIG. 16 is a diagram schematically showing a configuration of a conventional optical encoder.

[Description of Reference Numerals] 62 surface emitting semiconductor laser 64 scale 66 light receiving element 68 波長 wavelength plate 70a laser light 76 substrate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kenji Murakami 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Masataka Ito 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Sakae Hashimoto 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (3)

[Claims] 1. An optical encoder using a surface-emitting semiconductor laser, wherein the scale moves relatively to the surface-emitting semiconductor laser, and the scale is moved by a laser beam emitted from the surface-emitting semiconductor laser. A light-receiving element provided to receive reflected light or transmitted light from the scale when partially irradiating the scale, wherein the scale is provided with a unit for generating incoherent reflected light. An optical encoder, comprising: 2. A scale which moves relatively to a light source, a surface emitting semiconductor laser for irradiating a part of the scale, and a light receiving element for receiving reflected light or transmitted light from the scale. An optical encoder comprising: means for tilting an optical axis of light emitted from the surface emitting semiconductor laser. 3. An encoder having a scale that moves relative to a light source, a surface emitting semiconductor laser for irradiating a part of the scale, and a light receiving element for receiving light transmitted from the scale. In the scale, light-shielding regions and light-transmitting regions are alternately arranged, and at least the light-shielding region is divided into a plurality of minute regions, and the surface-emitting semiconductor laser is provided between the minute regions. An optical encoder characterized in that there is a height difference (N; 0 or a positive integer) corresponding to the optical path length of {N + (1/4)} wavelength of the outgoing light.