JP2001050778A - Displacement measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a photo-receiving element array having substantially fine array pitches by line/space machining with margin to provide a photo-electric type encoder enhanced in a yield and reliability. SOLUTION: This device has a scale member and a sensor head for reading a scale grating thereof, the sensor head is provided with an LED, an index scale for transmitting output light of the LED to irradiate a scale member, and a photo-receiving element array 5 for detecting the light modulated by the scale grating to output a displacement signal, and the photo-receiving array 5 has a substrate 50, a first photo-receiving element group 51a formed by a first layer semiconductor thin film formed on the substrate 50, an insulation film 24 for covering the first photo-receiving element group 51a, and a second photo-receiving element group 51b formed by a second layer semiconductor thin film formed on the insulation film 24 to receive the transmitted light in a space of the first photo-receiving element group 51a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a displacement measuring device such as a photoelectric encoder.

[0002]

2. Description of the Related Art As a photoelectric encoder, a light-receiving element array in which light-receiving elements are arrayed at a predetermined pitch in relation to a scale grating is used, and this light-receiving element array also serves as a light-receiving-side index grating. Are known. For example, with respect to the scale grating pitch P, at least four light receiving element arrays at P / 4 pitch (one set)
If the array is formed, A, AB,
B and BB four-phase displacement signals can be obtained. The pitch P of the scale grating becomes small, and the light receiving element array becomes P / 4.
If it is difficult to form the light receiving element array, for example, the array pitch of the light receiving element array may be set to 3P / 4. This allows
Four-phase displacement signals of A, BB, B, and AB having phases shifted by 270 ° in the order of arrangement of the light receiving element arrays can be obtained.

[0003]

However, when the pitch of the scale grid is as small as the μm level, it is not easy to form a light receiving element array. In particular, when the light receiving element array is formed by processing a semiconductor film such as amorphous silicon deposited on a substrate, and when the line / space is close to the minimum processing size, an inter-phase short-circuit or the like occurs, resulting in a low yield. . Further, even if fine lines / spaces can be processed, even if dust or the like adheres to the spaces, it may cause a short circuit.

The present invention has been made in view of the above circumstances, and realizes a light receiving element array having a substantially fine arrangement pitch by processing a sufficient line / space to improve the yield and reliability. It is intended to provide the intended photoelectric encoder. It is another object of the present invention to provide a displacement measuring device in which a transmission device array is substantially arranged at a fine pitch in an encoder of a capacitance type, a magnetic type, or the like.

[0005]

According to the present invention, there is provided a scale member on which a scale grating having a predetermined pitch is formed along a measuring axis, and the scale member is arranged so as to be relatively movable in the measuring axis direction with respect to the scale member. A sensor head for reading scale gratings, wherein the sensor head irradiates light to the scale member, and a light receiving element array that detects light from the scale member and outputs a plurality of displacement signals having different phases. Wherein the light-receiving element array includes a substrate, a first light-receiving element group formed by a first layer semiconductor thin film formed on the substrate, and a first light-receiving element group. An insulating film to cover, and a second light receiving element group formed of a second semiconductor thin film formed on the insulating film and receiving light transmitted through the space of the first light receiving element group. It is characterized.

According to the present invention, the light receiving element array is composed of the first light receiving element group and the second light receiving element group arranged in the space using semiconductor thin films of different layers on the substrate. Therefore, since the light receiving element array has a half pitch as a whole with respect to each pitch of the first and second light receiving element groups, the line / space processing of the light receiving element array can be performed with a margin. . Thereby, the yield and reliability of the photoelectric encoder are improved.

Specifically, in the present invention, the substrate of the light receiving element array is a transparent substrate, and the first and second light receiving element groups are laminated on the surface of the transparent substrate opposite to the surface facing the scale member. It is formed. In this case, the first and second
In each of the light receiving element groups, a transparent conductive film serving as a common electrode is formed on the transparent substrate side, and each terminal electrode is formed on the opposite side.

In the present invention, for example, the first light receiving element group has at least a pair of light receiving elements for outputting an A-phase displacement signal and an AB-phase displacement signal that are mutually opposite in relation to the scale lattice, The second light receiving element group is composed of A phase and AB
The phase displacement signal may include at least a pair of light receiving elements that output a B-phase and a BB-phase displacement signal, each of which is shifted by 90 ° in phase.

Further, in the present invention, for example, the first light receiving element group includes a plurality of light receiving elements which output an A-phase displacement signal and a B-phase displacement signal which are 90 ° out of phase with each other in relation to the scale grating. The first light receiving element group is composed of a first group and a second group, and the second light receiving element group has an AB phase displacement signal obtained by inverting the A phase with a light receiving surface covering the range of the first group of the first light receiving element group. And a second light receiving element that outputs a BB-phase displacement signal obtained by inverting the B-phase and having a light-receiving surface covering the range of the second group of the first light-receiving element group. can do.

Still further, in the present invention, the first light receiving element group is connected in parallel to each other to output an A-phase displacement signal, and the second light receiving element group is connected in parallel to each other to output an A-phase displacement signal.
It outputs a B-phase displacement signal 90 ° out of phase with the phase displacement signal. In addition, a third semiconductor thin film formed via an insulating film on the second light receiving element group And a third light receiving element group that is connected in parallel to each other and outputs a displacement signal of an AB phase that is opposite to the A phase, and is formed on the third light receiving element group via an insulating film. The fourth
B are formed of a semiconductor thin film of
And a fourth light receiving element group that outputs a displacement signal of a BB phase which is the opposite phase to the phase.

The present invention is also directed to a scale member having signal transfer portions arranged at a predetermined pitch along a measurement axis, and the signal transfer portion disposed so as to be relatively movable in the measurement axis direction with respect to the scale member. In a displacement measuring device having a transmitting unit that transmits a signal to, and a sensor head having a receiving unit that receives a signal transmitted via a signal transmitting unit of the scale member, the transmitting unit of the sensor head includes: A substrate, a first transmitting device arranged and formed on the substrate, an insulating film covering the first transmitting device, and the first transmitting device arranged on the insulating film so that the first transmitting device is out of phase with the first transmitting device. And a second transmission device formed.

According to the present invention, transmission devices can be substantially arranged at a fine pitch in a capacitance type encoder or a magnetic type encoder, whereby high resolution characteristics can be obtained. Specifically, (a) in the case of a capacitive encoder that performs signal transfer by capacitive coupling between the transmission unit and the signal transfer unit and between the signal transfer unit and the reception unit, the first and second transmission devices are: It is a transmission electrode. (B) In the case of a magnetic encoder that performs signal transfer by magnetic coupling between the transmission unit and the signal transfer unit and between the signal transfer unit and the reception unit, the first and second transmission devices are transmission windings. .

According to another aspect of the present invention, there is provided a scale member on which a scale grating having a predetermined pitch is formed along a measuring axis, and a sensor which is arranged so as to be relatively movable in the direction of the measuring axis with respect to the scale member and reads the scale grating. And a light source that irradiates the scale member with light, and a light receiving element array that detects light from the scale member and outputs a plurality of displacement signals having different phases. In the measuring device, the light receiving element array includes a substrate, a first group of waveguides formed on the substrate and configured to receive light from the scale member and guide the light as an optical signal, and the first waveguide. A clad layer covering the group, and a second group of waveguides formed on the clad layer and receiving the transmitted light in the space of the first group of waveguides and guiding the same as an optical signal. And butterflies.

That is, the present invention is also effective when the light receiving elements constituting the light receiving element array are not active elements but are waveguides that only receive and guide light. Also in this case, the pitch of the light receiving element array is reduced as a whole by forming a structure in which the first waveguide group and the second waveguide group are stacked with a shift of ピ ッ チ pitch with the clad layer interposed therebetween. It becomes possible.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] FIGS. 1A and 1B are a plan view of a photoelectric encoder according to Embodiment 1 of the present invention, and FIG.
It is A 'sectional drawing. The photoelectric encoder is opposed to the scale member 1 with a predetermined gap.
A sensor head 2 for reading a scale grating, which is arranged so as to be relatively movable along a measurement axis x of the scale member 1.
It is composed of

The scale member 1 is formed by arranging scale gratings 11 at a predetermined pitch P on a substrate 10 made of glass or the like. Specifically, in the case of this embodiment, the scale member 1 is of a reflective type, and the scale grating 11 is configured by an array of reflective portions and non-reflective portions. The sensor head 2 is
An LED 3 as a light source, and an index scale 4 for modulating the output light of the LED 3 to irradiate the scale member 1
And a light receiving element array 5 that receives reflected light from the scale member 1 and outputs a displacement signal.

The index scale 4 is formed by arranging, for example, index gratings 41 having the same pitch as the scale grating 11 on a transparent substrate such as glass. The light receiving element array 5 includes a light receiving element 51 formed of a semiconductor thin film such as amorphous silicon on a transparent substrate 51 such as glass.
Are arranged at a predetermined pitch in relation to the scale grating 11.

FIGS. 2A and 2B are a plan view showing a specific configuration of the light receiving element array 5 and a sectional view taken along line BB '. As shown in the figure, the light receiving element array 5 is composed of a first light receiving element group 51a and a second light receiving element group 51b which are stacked in two layers on a transparent substrate 50. The first light receiving element group 51a is an amorphous silicon photodiode 22 arranged and formed on a transparent conductive film 21 such as ITO formed as a common electrode on the transparent substrate 50. Each photodiode 22 is specifically a laminated film of a p-layer, an i-layer, and an n-layer from the substrate 50 side, and a terminal electrode 23 is formed on the surface thereof. The terminal electrode 23 is a Ni electrode.

The manufacturing process of the first light receiving element group 51a is as follows. First, a transparent conductive film 21 is formed on a substrate 50, and a p-layer, an i-layer, and an n-layer amorphous silicon film are sequentially deposited thereon, and a Ni film is further deposited on the surface thereof. Next, a Ni film is patterned through a lithography process. Then, each photodiode is separated by etching the amorphous silicon using the formed Ni electrode as a mask.

The first light receiving element group 51 thus formed
a is covered with an insulating film 24 such as a silicon oxide film. Preferably, the surface of the insulating film 24 is flattened. Then, a transparent conductive film 25 serving as a common electrode is formed on the insulating film 24 again,
The photodiode 26 of amorphous silicon constituting the second light receiving element group 51b is formed thereon. Terminal electrodes 27 are also formed on the surfaces of these photodiodes 26. The structure and manufacturing method of the second light receiving element group 51b are the same as those of the first light receiving element group 51a. The surface of the second light receiving element group 51b is covered with an insulating film 28 for passivation.

In this embodiment, the light receiving element array 5 receives light from the substrate 50 side. That is, the reflected light from the scale member 1 passes through the substrate 50 and is input to the first light receiving element group 51a. Second light receiving element group 51b
, The light transmitted through the substrate 50 and transmitted through the space of the first light receiving element group 51b is input.

In this embodiment, the light receiving element array 5
The first and second light receiving element groups 51a and 51b are arranged at a predetermined pitch so as to output four-phase displacement signals. Specifically, in the case of this embodiment, the first light receiving element group 51a is 3P / 2 with respect to the pitch P of the scale grating.
The second light receiving element group 51b is arranged at a pitch of
3P / 2 pitch shifted from the light receiving element group 51a of FIG.
They are arranged at a pitch. Assuming that the four-phase displacement signals whose phases are shifted by 90 ° are A, B, AB, and BB phases, the terminal electrodes of the first light receiving element group 51 a alternately have the A-phase signal line 31 a and the AB-phase signal line. Connected to line 31c. The terminal electrodes of the second light receiving element group 51b are alternately connected to the BB phase signal line 31b.
And the B-phase signal line 31d. As described above, from the light receiving element array 5, 3P / 4 pitch (= 270 °)
The displacement signals of the A, BB, B, and AB phases that are deviated from each other are obtained.

As described above, according to this embodiment, the light receiving element array 5 is composed of the first light receiving element group 51a and the second light receiving element group 51b formed of a different layer. Therefore, the first and second light receiving element groups 51a, 5a are arranged with respect to the arrangement pitch of the light receiving element array 5.
1b is doubled and the scale grid pitch P
Can be machined with a margin even if is small. Thereby, the yield and reliability of the light receiving element array are improved.

[Embodiment 2] When the scale grating pitch P is large, the arrangement pitch of the light receiving element arrays 5 can be set to, for example, P / 4. FIG. 3 shows a layout of the light receiving element array 5 of such an embodiment corresponding to FIG. The cross-sectional structure is the same as in the first embodiment. In this case, as shown in FIG. 3, the first light receiving element group 51a and the second light receiving element group 51b are arranged at a P / 2 pitch while being shifted from each other by a P / 4 pitch. Thereby, the first and second light receiving element groups 51a, 51
From the light receiving element array 5 including 1b, displacement signals of four phases A, B, AB, and BB are obtained in the order of arrangement.

Also in this embodiment, since the light receiving element array 5 has a two-layer structure, the actual element processing pitch is twice as large as the finally obtained element arrangement pitch. Array yield and reliability are improved. In the above-described embodiments, the first light receiving element group 51a and the second light receiving element group 51b have been described as examples in which the line / space is not 1/1 and the space is slightly larger. Line / space = 1/1 may be set. In this case, the light receiving elements are arranged without gaps in the entire light receiving element array.

Third Embodiment FIG. 4 shows a sectional structure of a light receiving element array 5 of a photoelectric encoder according to a third embodiment. In this embodiment, a first light receiving element group 51b and a second light receiving element group 51b are formed on a substrate 50 in the same manner as in the first embodiment, and a third light receiving element group 51c is formed thereon. The fourth light receiving element group 51d is stacked. The separation between the light receiving element groups 51a, 51b, 51c, and 51d by the insulating film 41 is the same as in the previous embodiment.

In this embodiment, the first light receiving element groups 51a are arranged at a pitch P and are connected in parallel with each other. The second to fourth light receiving element groups 51b to 51d sequentially have P /
They are formed so as to be shifted by four and are connected to each other in parallel. Thereby, the first to fourth light receiving element groups 51a
Outputs of .about.51d are displacement signals of the A, B, AB, and BB phases, respectively. As a result, a large space between adjacent elements can be ensured in the processing of each light receiving element group, and a P / 4 pitch element array can be obtained as the entire light receiving element array, and a photoelectric encoder having a fine scale grid Can be made with good yield.

[Fourth Embodiment] FIG. 5 shows a sectional structure of a light receiving element array 5 of a photoelectric encoder according to a fourth embodiment. In this embodiment, the first light receiving element group 51a formed on the substrate 50 is a first group 51aa including a plurality of photodiodes 22a arranged at a pitch P.
And a plurality of photodiodes 22b arranged at the same pitch P, and is divided into a first group 51aa and a second group 51ab shifted by 90 ° in phase.
The plurality of photodiodes 22a of the first group 51aa
Are connected in parallel with each other for the A phase, and the second group 51
The plurality of photodiodes 22b of ab are connected in parallel for the B phase.

The second light receiving element group 51b laminated on the first light receiving element group 51a via an insulating film is composed of two photodiodes 26a and 26b. The photodiodes 26a and 26b are formed so as to have light receiving surfaces that cover the entire first and second groups 51a1 and 51a2, respectively.

The first light receiving element group 51a functions as a grating if the terminal electrodes of the photodiodes 22a and 22b do not transmit light. Accordingly, one photodiode 26a of the second light receiving element group 51b is connected to the first photodiode 26a.
The light transmitted through the space of the photodiode 22a of the first group 51aa of the light receiving element group 51a of FIG.
A B-phase displacement signal is output. The other photodiode 26b of the second light receiving element group 51b is connected to the first light receiving element group 51b.
The light receiving device transmits the light transmitted through the space of the photodiode 22b of the second group 51ab of FIG. According to this embodiment, the same effects as those of the previous embodiments can be obtained.

The photoelectric encoder according to the present invention is not limited to the above embodiment. For example, in each of the above embodiments,
A transparent substrate is used for the light receiving element array, and light receiving elements are laminated and formed on the surface opposite to the side facing the scale member,
Although the light transmitted through the transparent substrate is received, the side on which the light receiving elements are stacked may be used as the light incident surface. At this time, when a metal is used for the terminal electrode of each light receiving element, it is necessary to turn the terminal electrode and the transparent common electrode upside down from the above embodiment. Further, the substrate need not be a transparent substrate. In the above embodiment, the case where a four-phase displacement signal is obtained has been described. However, the present invention can be similarly applied to a photoelectric encoder that obtains a three-phase displacement signal that is shifted by 120 °.

[Embodiment 5] FIGS. 6 and 7 show an embodiment in which the present invention is applied to a capacitance type encoder. Having a scale member 1 and a sensor head 2 opposed thereto is the same as the photoelectric encoder. Transfer electrodes 102 are arranged and formed on the scale member 1 at a predetermined pitch. On the sensor head 2, a transmission electrode 101 and a reception electrode 103 that are capacitively coupled to the transfer electrode 102 are arranged. A plurality of transmission electrodes 101 are arranged at a predetermined pitch in relation to the arrangement of the transfer electrodes 102 of the scale member 1.

As shown in the sectional view of FIG. 7, the arrangement of the transmission electrodes 101 includes a first transmission electrode 101a arranged on a substrate 100 and a second transmission electrode 101a arranged on the first transmission electrode 101a with an interlayer insulating film 104 interposed therebetween. And the transmission electrode 101b. The second transmission electrode 101b is arranged in the space of the arrangement of the first transmission electrode 101a, and for example, as shown in FIG. 7, A, B, C,
A group of four-phase transmitting electrodes having different Ds is formed. Also in the case of this embodiment, the plurality of transmitting electrodes are arranged in two layers.
Taking the transmission electrode arrangement pitch of each layer as P, the transmission electrode pitch P / 2 can be realized as a whole. Therefore, an electrode arrangement with a fine pitch can be obtained.

[Embodiment 6] FIGS. 8 and 9 show an embodiment in which the present invention is applied to a magnetic (inductive) encoder. Having a scale member 1 and a sensor head 2 opposed thereto is the same as the photoelectric encoder. The transfer windings 202 are arranged and formed on the scale member 1 at a predetermined pitch. On the sensor head 2, a transfer winding 102
A transmission winding 201 and a reception winding 203 that are magnetically coupled to each other (inductive coupling) are arranged. A plurality of transmission windings 201 are arranged at a predetermined pitch in relation to the arrangement of the transfer windings 202 of the scale member 1.

As shown in the sectional view of FIG. 9, the arrangement of the transmission windings 201 is such that a first transmission winding 201a arranged on a substrate 200 and an intervening insulating film 204 are arranged thereon. And a second transmission winding 201b. The second transmission winding 201b is arranged in the space of the arrangement of the first transmission winding 201a, and for example, A, B, C,
A group of four-phase transmission windings having different Ds is formed. Also in this embodiment, a plurality of transmission windings are arranged in two layers.
Taking the transmission winding arrangement pitch of each layer as P, the transmission winding pitch P / 2 can be realized as a whole. Therefore, a winding arrangement having a fine pitch can be obtained.

[Embodiment 7] FIG. 10 shows Embodiment 1 of the present invention.
2 shows a configuration of another light receiving element array 5a corresponding to the light receiving element array 5 in FIG. Here, as light receiving elements, simple optical waveguides 302a and 302 having no active region are used.
2b is used. FIGS. 11A and 11B are sectional views taken along the lines AA 'and BB' of FIG. The waveguides 302a,
Reference numeral 302b denotes a planar waveguide (core layer) formed by depositing and etching a thin film.

That is, the first waveguides 302a are arranged at a predetermined pitch on the substrate 201 so as to be surrounded by the cladding layer 303, and the second waveguides 302b are further formed on the first waveguides 302a.
Are arranged with a ピ ッ チ pitch shift from the arrangement of the waveguides 302a. A cladding layer 304 is also formed above the second waveguide 302b. Each waveguide 302a, 302
b is arranged in parallel with the substrate 301 in a stripe shape in a direction orthogonal to the measurement axis of the scale. Light from the scale is coupled from the surface orthogonal to the end face, not the waveguide end face.

Specifically, in this embodiment, the waveguide 30
Light is coupled to the waveguides 302a and 302b from the surface of the cladding layer 304 on the side where the 2a and 302b are formed.
Therefore, as shown in FIG.
The light entering the cladding layer 304 from the scale is efficiently guided onto the surface of the upper cladding layer 304a, 302b.
02a and 302b as optical couplers.
A grating 305 is formed. The grating 305 can be formed using exposure of interference fringes and etching of a cladding layer. When the grating 305 is formed in this manner, the substrate 30 can be formed in the cross section shown in FIG.
Assuming that light from the scale enters in a direction substantially perpendicular to 1, the light is diffracted into the cladding layer 304 at an angle θ represented by dsin θ = mλ (d: grating pitch, λ: light source wavelength, m: integer). Then, the waveguides 302a,
302b.

When the substrate 301 is transparent, light from the scale may enter the waveguides 302a and 302b from the substrate 301 side. Each waveguide 302a, 30
An optical fiber 3 is connected to one end of
07 are connected. Using the bundle of the optical fibers 307 as an optical transmission line 308, optical signals obtained from the respective waveguides 302a and 302b are transferred to a measuring device (not shown). The waveguides 302a and 302b have a two-layer structure, and the scale pitch is P as a whole.
Books are arranged as one set. Thereby, A, B
Four-phase optical signals B, B, and AB are obtained.

Also in this embodiment, by forming the waveguide group forming the light receiving element array into a two-layer structure, it is possible to obtain a fine light receiving element arrangement of ピ ッ チ the actual processing pitch. The waveguide group is effective if it has at least two layers. However, as in the embodiment shown in FIG.

[0041]

As described above, according to the present invention, by forming the light receiving element array from a plurality of light receiving element groups, the light receiving element array having a substantially fine arrangement pitch can be formed on a line / line having a sufficient margin. This can be realized by processing the space to improve the yield and reliability of the photoelectric encoder. Further, according to the present invention, in a capacitive or magnetic encoder, a transmission device array of a transmission unit of a sensor head facing a scale member has a two-layer structure, so that the transmission unit array is finely pitched and a high-resolution encoder is provided. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a photoelectric encoder according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a configuration of a light receiving element array in the embodiment.

FIG. 3 is a diagram showing a configuration of a light receiving element array of a photoelectric encoder according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a light receiving element array of a photoelectric encoder according to Embodiment 3 of the present invention.

FIG. 5 is a diagram showing a configuration of a light receiving element array of a photoelectric encoder according to Embodiment 4 of the present invention.

FIG. 6 is a diagram showing a configuration of a capacitive encoder according to Embodiment 5 of the present invention.

FIG. 7 is a cross-sectional view of a transmission electrode array portion of the capacitance type encoder.

FIG. 8 is a diagram showing a configuration of a magnetic encoder according to Embodiment 6 of the present invention.

FIG. 9 is a sectional view of a transmission winding array portion of the magnetic encoder.

FIG. 10 is a diagram showing a configuration of a light receiving element array of a photoelectric encoder according to Embodiment 7 of the present invention.

FIG. 11 is a diagram showing a cross-sectional structure of the light receiving element array according to the embodiment.

[Explanation of symbols]

1 scale member, 2 sensor head, 3 LED, 4
... Index scale, 5 ... Light receiving element array, 50 ...
Substrate, 51: light receiving element, 51a: first light receiving element group, 5
1b: second light receiving element group, 21, 25: transparent conductive film, 2
2, 26 ... photodiode, 23, 27 ... terminal electrode,
24, 28 ... insulating film, 101 (101a, 101b) ...
Transmission electrode, 102: transfer electrode, 103: reception electrode, 20
1 (201a, 201b): transmission winding, 202: transfer winding, 203: reception winding, 5a: light receiving element array, 302
a, 302b: waveguide, 203, 204: clad layer,
305 ... Grating, 306 ... Connector, 307 ...
Optical fiber.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2F065 AA02 AA07 FF02 FF16 GG07 HH02 HH12 JJ01 JJ05 JJ07 JJ18 JJ25 KK01 LL01 MM03 PP22 QQ03 2F077 AA00 AA25 NN05 NN24 NN28 PP06 RR03 TT07 FB03 TT032 EA19 EB06 EB12 EB16 EB21 EB32 EB37 EC07 FA01

Claims (10)

[Claims] 1. A scale member on which a scale grating having a predetermined pitch is formed along a measurement axis, and a sensor head which is arranged so as to be relatively movable in the measurement axis direction with respect to the scale member and reads the scale grating. Having a light source for irradiating the scale member with light,
A displacement measuring device comprising: a light-receiving element array that detects light from the scale member and outputs a plurality of displacement signals having different phases; wherein the light-receiving element array includes: a substrate; and a first light-receiving element formed on the substrate. A first light receiving element group formed by a layer semiconductor thin film; an insulating film covering the first light receiving element group; and a first light receiving element formed by a second layer semiconductor thin film formed on the insulating film. A second light receiving element group for receiving the transmitted light in the space of the element group. 2. The method according to claim 1, wherein the substrate is a transparent substrate, and the first and second light receiving element groups are laminated on a surface of the transparent substrate opposite to a surface facing the scale member. The displacement measuring device according to claim 1, wherein 3. The first and second light receiving element groups, wherein a transparent conductive film serving as a common electrode is formed on the transparent substrate side, and each terminal electrode is formed on the opposite side. Item 3. The displacement measuring device according to Item 2. 4. The first light-receiving element group includes at least a pair of light-receiving elements that output an A-phase displacement signal and an AB-phase displacement signal that are opposite to each other in relation to the scale grating. 2. The light-receiving element group of claim 2, wherein at least one pair of light-receiving elements that output B-phase and BB-phase displacement signals that are 90 ° out of phase with the A-phase and AB-phase displacement signals, respectively. The displacement measuring device as described. 5. The first light receiving element group includes a plurality of light receiving elements that output an A-phase displacement signal and a B-phase displacement signal that are 90 ° out of phase with respect to the scale grating. A first group and a second group, wherein the second light receiving element group is a first group of the first light receiving element group.
A first light receiving element for outputting an AB phase displacement signal having an A phase inverted with a light receiving surface covering the range of the group, and a B light receiving surface covering the range of the second group of the first light receiving element group. The displacement measuring apparatus according to claim 1, further comprising a second light receiving element that outputs a BB phase displacement signal whose phase is inverted. 6. The first light receiving element group is connected in parallel to each other to output an A-phase displacement signal, and the second light receiving element group is connected in parallel to each other to output an A-phase displacement signal. Means to output a B-phase displacement signal having a phase shift of 90 °, and is formed of a third semiconductor thin film formed on the second light receiving element group via an insulating film, and is parallel to each other. A third light receiving element group that is connected and outputs a displacement signal of an AB phase opposite to the A phase, and a fourth semiconductor thin film formed on the third light receiving element group via an insulating film 2. A displacement measuring apparatus according to claim 1, further comprising: a fourth group of light receiving elements which are connected in parallel with each other and output a displacement signal of a BB phase which is a phase opposite to the B phase. 7. A scale member having signal transfer portions arranged at a predetermined pitch along a measurement axis, and a scale member disposed so as to be relatively movable in a measurement axis direction with respect to the scale member and to the signal transfer portion. In a displacement measuring device having a transmitting unit that transmits a signal, and a sensor head having a receiving unit that receives a signal transmitted via a signal transmitting unit of the scale member, the transmitting unit of the sensor head includes: a substrate; A first transmitting device arranged and formed on the substrate, an insulating film covering the first transmitting device, and a first transmitting device arranged and formed on the insulating film so as to be out of phase with the first transmitting device; A displacement measuring device, comprising: a second transmitting device. 8. A signal transfer is performed by capacitive coupling between the transmission unit and the signal transfer unit and between the signal transfer unit and the reception unit, and the first and second transmission devices are transmission electrodes. The displacement measuring device according to claim 7, wherein: 9. A signal transfer is performed by magnetic coupling between the transmission unit and the signal transfer unit and between the signal transfer unit and the reception unit, and the first and second transmission devices are transmission windings. 8. The displacement measuring device according to claim 7, wherein: 10. A scale member on which a scale grating having a predetermined pitch is formed along a measurement axis, and a sensor head which is disposed so as to be relatively movable in the measurement axis direction with respect to the scale member and reads the scale grating. Wherein the sensor head includes a light source that irradiates the scale member with light, and a light receiving element array that detects light from the scale member and outputs a plurality of displacement signals having different phases. The light receiving element array includes a substrate, a first group of waveguides formed on the substrate to receive light from the scale member and guide the light as an optical signal, and covers the first group of waveguides. A cladding layer; and a second group of waveguides formed on the cladding layer and configured to receive the transmitted light in the space of the first group of waveguides and guide them as optical signals. Position measurement device.