WO2016039166A1

WO2016039166A1 - Position sensor

Info

Publication number: WO2016039166A1
Application number: PCT/JP2015/074331
Authority: WO
Inventors: 良真吉岡; 柴田　直樹; 裕介清水
Original assignee: 日東電工株式会社
Priority date: 2014-09-12
Filing date: 2015-08-28
Publication date: 2016-03-17
Also published as: JP2016058014A; TW201614456A

Abstract

The invention provides a position sensor with which it is possible to achieve space savings. In the position sensor, second to fourth optical waveguides W2 to W4 having linear cores 2r communicating with a lattice-shaped core 2 are positioned on a reverse surface side of a first optical waveguide W1 having the lattice-shaped core 2. A light-emitting element 4 is connected to the first optical waveguide W1 and the second optical waveguide W2, and a light-receiving element 5 is connected to the third optical waveguide W3 and the fourth optical waveguide W4. Propagation of light between the lattice-shaped core 2 of the first optical waveguide W1 on the obverse surface side and the linear cores 2r of the second to fourth optical waveguides W2 to W4 on the reverse surface side is made possible by employing light reflection from a light-reflecting member 6.

Description

Position sensor

The present invention relates to a position sensor that optically detects a pressed position.

The present applicant has proposed a position sensor that optically detects the pressed position (see, for example, Patent Document 1). As shown in FIG. 8, this has a rectangular sheet-shaped optical waveguide W in which a sheet-shaped core pattern member is sandwiched between a rectangular sheet-shaped underclad layer 11 and an overclad layer 13. The core pattern member includes a lattice-shaped portion 12A formed by arranging a plurality of linear optical path cores 12 vertically and horizontally, and extends from the core 12 of the lattice-shaped portion 12A to the outer periphery of the lattice-shaped portion 12A. The outer peripheral part 12B arrange | positioned in the state along is provided. A light emitting element 14 is connected to one end face of the core 12 of the outer peripheral portion 12B of the core pattern member, and a light receiving element 15 is connected to the other end face of the core 12. In the position sensor, both the light emitting element 14 and the light receiving element 15 are provided at the same one end edge (lower end edge in FIG. 8) of the rectangular sheet-shaped optical waveguide W, and the light emitting element 14 is one end portion of the end edge. (The left end portion in FIG. 8), and the light receiving element 15 is disposed at the other end portion of the end edge (the right end portion in FIG. 8).

In the position sensor, the surface portion of the over clad layer 13 corresponding to the lattice-shaped portion 12A of the core pattern member (a rectangular portion indicated by a one-dot chain line in the center of FIG. 8) is an input region 13A of the position sensor. Further, a portion (a portion around the input region 13A) where the outer peripheral portion 12B of the core pattern member is sandwiched between the side edge portion of the under cladding layer 11 and the side edge portion of the over cladding layer 13 is the periphery of the optical waveguide W. It is a part (frame part) F.

In the position sensor, the light emitted from the light emitting element 14 passes through the core 12 from the outer peripheral portion 12B connected to the light emitting element 14 to the opposite outer peripheral portion 12B through the lattice portion 12A. The light receiving element 15 receives light. When the input area 13A corresponding to the grid portion 12A is pressed with a pen tip or the like, the core 12 of the pressed portion is deformed, and the light propagation amount of the core 12 is reduced. Therefore, in the core 12 of the pressing portion, the light receiving level at the light receiving element 15 is lowered, so that the pressing position can be detected.

Japanese Patent No. 5513656

Generally, it is said that this type of position sensor is easy to handle a flat sensor, which has become common technical knowledge. However, the position sensor requires a larger space than the input region 13A due to the presence of the peripheral portion F around the input region 13A. Further, when the input area 13A of the position sensor is widened or the detection accuracy of the pressed position in the input area 13A is improved, it is necessary to increase the number of cores 12, and accordingly, the width of the peripheral portion F is increased. Need to be wide. For this reason, the position sensor requires a larger space. In that respect, the position sensor has room for improvement.

The present invention has been made in view of such circumstances, and an object thereof is to provide a position sensor capable of saving space.

In order to achieve the above object, a position sensor according to the present invention includes a sheet-like optical waveguide including a plurality of linear cores formed in a lattice shape and two clad layers sandwiching the lattice-like core. A light-emitting element that supplies light into the lattice-like core of the optical waveguide, a light-receiving element that receives the supplied light through the core, a back surface side of the optical waveguide, A linear core for connecting elements connected to the lattice-shaped core, and a sheet-shaped end surface of the optical waveguide, which reflects light and reflects the light on the front surface side of the lattice-shaped core and the back surface side. A position sensor including a light reflecting member that enables light propagation between the linear core, and the light emitting element or the light receiving element is connected to the linear core on the back surface side, The surface area of the position sensor corresponding to the grid-shaped core is used as the input area. Pressing position in the input area, a configuration that identifies the light propagation quantity of the core that has changed by the pressing.

That is, the position sensor of the present invention breaks the conventional common sense, and at least a part of the peripheral portion (frame portion) of the conventional position sensor is separated from the input region, and the input region It is in the state moved to the back side. Then, the light propagation between the core of the input region (lattice core) in the separated state and the core on the back surface side is possible by light reflection on the light reflecting member provided on the end surface of the input region. It is said.

The position sensor of the present invention is provided with a linear core for element connection that communicates with the lattice-shaped core on the front surface side on the back side of the optical waveguide having the lattice-shaped core, and the light emission is provided on the core. The element or the light receiving element is connected. A light reflecting member is provided on the sheet-like end face of the optical waveguide to reflect light and allow light propagation between the lattice-like core on the front surface side and the linear core on the back surface side. It has been. That is, the position sensor of the present invention is in a state in which at least a part of the peripheral portion (frame portion) of the conventional position sensor is separated from the input area and moved to the back side of the input area. The light reflecting member enables light propagation between the lattice core on the front surface side and the linear core on the back surface side. Therefore, the position sensor of the present invention is space-saving compared with the conventional position sensor by the amount of the linear core for connecting the element provided on the back side of the optical waveguide. .

In particular, the light reflecting member is made of either metal or resin, and reflects the light coming from one of the front surface side of the lattice-like core and the back surface side of the linear core, thereby allowing the light to be reflected. Either the first inclined surface passing along the thickness direction of the end face of the waveguide, or the lattice-like core on the front side and the linear core on the back side by further reflecting light along the thickness direction of the end face In the case where the second inclined surface leading to the core on the other surface side is provided, the structure of the light reflecting member can be simplified, so that the width of the light reflecting member can be reduced. As a result, the position sensor of the present invention can be further reduced in space.

Furthermore, when the first and second inclined surfaces are light reflecting surfaces that convert the optical path by 90 °, the width of the light reflecting member can be further reduced. The sensor can further save space.

One embodiment of the position sensor of the present invention is shown typically, (a) is the top view, and (b) is the expanded sectional view of the side edge portion. The 1st optical waveguide which constitutes the above-mentioned position sensor is shown typically, (a) is the top view, and (b) is the expanded sectional view of the central part. FIG. 6 is a plan view schematically showing second to fourth optical waveguides constituting the position sensor. It is an expanded sectional view showing typically the side edge part of other embodiments of the position sensor of the present invention. It is a top view which shows typically the optical waveguide base | substrate produced in the other manufacturing method of the position sensor of this invention. (A) to (f) are enlarged plan views schematically showing a crossing form of lattice-like cores in the position sensor. (A), (b) is an enlarged plan view which shows typically the course of the light in the cross | intersection part of the said grid | lattice-like core. It is a top view which shows the conventional position sensor typically.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 (a) is a plan view showing an embodiment of the position sensor of the present invention, and FIG. 1 (b) is an enlarged view of a side edge portion thereof. The position sensor of this embodiment includes a first optical waveguide W1 having a substantially rectangular sheet shape having a lattice-shaped core 2 and a core 2q extending from one end of the core 2, and the first optical waveguide W1. Second to fourth optical waveguides W2 having linear cores 2r that are provided on the back surface side of the side edge portions at three locations (on the left and right sides and the lower side in FIG. 1A) and that communicate with the lattice-shaped cores 2. To W4 (invisible in the first optical waveguide W1 in FIG. 1A). Further, the light emitting element 4 is connected to the first optical waveguide W1 and the second optical waveguide W2 (the back side of the right edge portion in FIG. 1A), and the third optical waveguide W3 (the lower side in FIG. 1A). The light receiving element 5 is connected to the rear surface side of the side edge portion] and the fourth optical waveguide W4 (the rear surface side of the left edge portion in FIG. 1A) (see FIGS. 1B and 3). Then, light is reflected to the outside of the side edge portion of the first optical waveguide W1 provided with the second to fourth optical waveguides W2 to W4, and the lattice-like core of the first optical waveguide W1 on the surface side is reflected. A light reflecting member 6 is provided that enables light propagation between 2 and the linear cores 2r of the second to fourth optical waveguides W2 to W4 on the back side.

In FIG. 1A, the

cores

2 and 2q are indicated by chain lines, and the thickness of the chain line indicates the thickness of the

cores

2 and 2q. Furthermore, the number of the lattice-like cores 2 is omitted, and the interval between the cores 2 is widened. The arrow indicates the direction in which the light travels. In FIG. 1B, reference numeral E denotes an electric circuit board on which the light emitting element 4 or the light receiving element 5 is mounted, and the light emitting elements connected to the second to fourth optical waveguides W2 to W4. 4 or the light receiving element 5 is provided on the back side of the first optical waveguide W1.

In this way, the second to fourth optical waveguides W2 to W4 having the lattice-shaped core 2 and the linear core 2r for light propagation are positioned on the back surface side of the first optical waveguide W1 having the lattice-shaped core 2. Then, light propagation between the lattice-shaped core 2 of the first optical waveguide W1 on the front surface side and the linear core 2r of the second to fourth optical waveguides W2 to W4 on the back surface side is performed on the light reflecting member. It is a great feature of the present invention that the light reflection at 6 is made possible. Due to this feature, space saving of the position sensor is achieved.

More specifically, the first optical waveguide W1 on the front surface side is shown in a plan view in FIG. 2A and in an enlarged cross-sectional view in FIG. Are extended from a plurality of linear optical path cores 2 formed in a lattice shape and one end of the lattice-shaped core 2 (the upper end of the longitudinal core 2 in FIG. 2A). And the extended core 2q disposed along the end face of the lattice portion (the upper end face in FIG. 2A) is formed, and the under clad layer is covered with the

cores

2 and 2q. The over clad layer 3 is formed on the surface of 1. A surface portion of the over clad layer 3 corresponding to the lattice-like core 2 is an input region 3A. Further, the light emitting element 4 is connected to the tip of the extended core 2q.

On the other hand, the second to fourth optical waveguides W2 to W4 on the back side are formed with a plurality of linear optical path cores 2r as shown in a plan view in FIG. Similar to the optical waveguide W1 (see FIGS. 2A and 2B), it is sandwiched between the under cladding layer 1 and the over cladding layer 3. The light emitting element 4 or the light receiving element 5 is connected to one end of the core 2r, and the other end 2d of the core 2r is connected to the end 2c of the lattice-like core 2 on the surface side [FIG. It is positioned at a position corresponding to (see a)] (overlapping in plan view). In FIG. 3, for ease of understanding, the electric circuit board E [see FIG. 1B] on which the light emitting element 4 or the light receiving element 5 is mounted is not shown.

In this embodiment, the light reflecting member 6 is made of metal, and as shown in FIGS. 1A and 1B, the light reflecting member 6 is a rod-like body along the longitudinal direction of the end face of the first optical waveguide W1. Yes. A concave groove 6a is formed on the surface of the light reflecting member 6 facing the end surface of the first optical waveguide W1 along the longitudinal direction of the light reflecting member 6, and the side wall of the concave groove 6a [FIG. 1 (b), the upper wall and the lower wall] are formed on light reflecting surfaces (first and second inclined surfaces) 6b and 6c inclined by 45 °.

The propagation of light through such a position sensor is as follows, for example, as shown in FIG. That is, light from the light emitting element 4 connected to the first optical waveguide W1 on the surface side first passes through the extended core 2q in the first optical waveguide W1 and passes through the lattice-shaped vertical core 2 from above. Propagating downward and exiting from the lower end 2c of the core 2 as shown in FIG. Next, the emitted light is reflected by the upper light reflecting surface 6b of the light reflecting member 6 to change the optical path by 90 °, propagates along the thickness direction of the end surface of the first optical waveguide W1, and the light reflected. The light is reflected again by the lower light reflecting surface 6c of the member 6 to change the optical path by 90 °, and enters the end 2d of the core 2r of the third optical waveguide W3 on the back surface side. The incident light propagates through the core 2r of the third optical waveguide W3 and is received by the light receiving element 5.

On the other hand, the light from the light emitting element 4 connected to the second optical waveguide W2 on the back side first propagates through the core 2r of the second optical waveguide W2, as shown in FIG. It is emitted from 2d. Next, the emitted light is reflected by the light reflecting surface 6c on the lower side of the light reflecting member 6 as shown in FIG. 1B (however, the light travels in the opposite direction to the illustrated arrow). The optical path is converted by 90 °, propagated along the thickness direction of the end surface of the first optical waveguide W1, reflected again by the light reflecting surface 6b on the upper side of the light reflecting member 6 and converted by 90 °, and the surface side The first optical waveguide W1 is incident on the right end portion 2c (see FIG. 2A) of the lattice-like lateral core 2 in the lattice direction. Next, the incident light propagates from the right to the left in the lattice-like horizontal core 2 in the first optical waveguide W1 and is emitted from the left end 2c of the core 2. Then, the emitted light is reflected by the light reflecting member 6 in the same manner as described above (see FIG. 1B) and is incident on the end 2d of the core 2r of the fourth optical waveguide W4 on the back surface side. Then, it propagates through the core 2r of the fourth optical waveguide W4 and is received by the light receiving element 5.

In this way, light propagates to the core 2 in the above-mentioned lattice-like vertical direction and horizontal direction (XY direction). Input of characters and the like to the position sensor is performed on the input region (surface portion of the over clad layer 3 corresponding to the lattice-like core 2) 3A directly or via a resin film or paper. This is done by writing characters etc. in the input field. At this time, the input area 3A is pressed with a pen tip or the like, the core 2 of the pressed portion is deformed, and the light propagation amount of the core 2 is reduced. For this reason, the light receiving level at the light receiving element 5 connected to the core 2 of the pressed portion is lowered, so that the pressed position (XY coordinate) can be detected.

Further, in this embodiment, the light emitting element 4 and the light receiving element 5 are indirectly connected to the lattice-shaped core 2 in the two vertical directions and the horizontal direction (XY direction), respectively. Therefore, the two directions can be controlled separately, and the detection accuracy of the pressed position in the input area 3A can be improved.

Furthermore, in the first optical waveguide W1, it is preferable that the elastic modulus of the lattice-like core 2 is set larger than the elastic modulus of the under cladding layer 1 and the over cladding layer 3. The reason is that if the elastic modulus is set in the opposite direction, the periphery of the core 2 becomes hard, so that the optical waveguide having an area considerably larger than the area of the pen tip or the like that presses the input region 3A portion of the over clad layer 3 This is because the W portion is recessed and it is difficult to accurately detect the pressed position. Therefore, as each elastic modulus, for example, the elastic modulus of the core 2 is set within a range of 1 GPa or more and 10 GPa or less, and the elastic modulus of the over clad layer 3 is set within a range of 0.1 GPa or more and less than 10 GPa, The elastic modulus of the under cladding layer 1 is preferably set within a range of 0.1 MPa to 1 GPa. In this case, since the elastic modulus of the core 2 is large, the core 2 is not crushed by a small pressing force (the cross-sectional area of the core 2 is not reduced), but the first optical waveguide W1 is recessed by the pressing, so that the recessed portion Since light leakage (scattering) occurs from the bent portion of the corresponding core 2 and the light receiving level at the light receiving element 5 connected to the core 2 decreases, the pressed position can be detected. The elastic modulus of the core 2r and the like of the second to fourth optical waveguides W2 to W4 may be set to be the same as that of the first optical waveguide W1, or may be set to another elastic modulus. .

Examples of the material for forming the under cladding layer 1, the

cores

2, 2q, and 2r and the over cladding layer 3 include photosensitive resins and thermosetting resins. The fourth optical waveguides W1 to W4 can be manufactured. Further, the refractive indexes of the

cores

2, 2 q and 2 r are set to be larger than the refractive indexes of the under cladding layer 1 and the over cladding layer 3. The refractive index and the elastic modulus can be adjusted by, for example, selecting the type of each forming material and adjusting the composition ratio. The thickness of each layer is set, for example, in the range of 10 to 500 μm for the under cladding layer 1, in the range of 5 to 100 μm for the

cores

2, 2 q and 2 r, and in the range of 1 to 200 μm for the over cladding layer 3. . Note that a rubber sheet may be used as the undercladding layer 1 and the cores 2 may be formed in a lattice shape on the rubber sheet.

FIG. 4 is an enlarged sectional view showing a side surface portion of another embodiment of the position sensor of the present invention. In this embodiment, in the above-described embodiment shown in FIGS. 1A and 1B, the light reflecting member 7 is a resinous optical waveguide (fifth optical waveguide). The light reflecting member (fifth optical waveguide) 7 has a plurality of cores 7a at positions corresponding to the end 2c of the lattice-like core 2 on the front surface side and the end 2d of the linear core 2r on the back surface side. It is formed along the thickness direction of the end face of the first optical waveguide W1, and the core 7a is sandwiched between the under cladding layer 7d and the over cladding layer 7e. Then, both end surfaces of the core 7a are formed as inclined surfaces inclined by 45 ° with respect to the axial direction of the core 7a, and the inclined surfaces reflect light and reflect light by converting the light path by 90 °, 7c. Here, the outside of the inclined surface is air, and the refractive index is smaller than that of the inner core 7a. Therefore, the inclined surface becomes the

light reflecting surfaces

7b and 7c as described above. The other parts are the same as those in the embodiment shown in FIGS. 1A and 1B, and the same reference numerals are given to the same parts.

In this embodiment, since the light reflecting member 7 is an optical waveguide, the width of the light reflecting member 7 can be reduced, so that the position sensor can be further saved in space.

In each of the above embodiments, the first to fourth optical waveguides W1 to W4 are individually manufactured, and the second to fourth optical waveguides W2 to W4 are provided on the back surface side of the first optical waveguide W1. Other methods may be used. For example, as shown in a plan view in FIG. 5, the second to fourth optical waveguides W2 to W4 are directly connected to the first optical waveguide W1 and spread on the plane in advance. An optical waveguide substrate W0 is manufactured, the portion corresponding to the second to fourth optical waveguides W2 to W4 is cut from the optical waveguide substrate W0, and the remaining portion is used as the first optical waveguide W1. The cut second to fourth optical waveguides W2 to W4 may be provided on the back side of the waveguide W1.

In each of the above embodiments, the linear cores (second to fourth) are arranged on the back surface side of three of the four side edge portions of the region (input region 3A) of the lattice-like core 2 on the front side. (Linear cores of the optical waveguides W2 to W4) 2r are provided, but may be other, for example, may be provided on the back side of all four side edge portions, may be two locations, or may be only one location. Good.

Further, in each of the above embodiments, the

light reflecting members

6 and 7 are made of metal rods and resin optical waveguides. However, the

light reflecting members

6 and 7 reflect light, and the lattice-like cores 2 on the front side and the lines on the back side are reflected. Any other material may be used as long as it allows light to propagate between the core 2r. In each of the above embodiments, the

light reflecting members

6 and 7 make two reflections for converting the optical path by 90 °. However, the optical path conversion angle and the number of reflections may be other as long as the light propagation is possible. .

In each of the above embodiments, each of the intersecting portions of the lattice-like core 2 is normally formed in a state in which all four intersecting directions are continuous, as shown in an enlarged plan view in FIG. There are others. For example, as shown in FIG. 6B, only one intersecting direction may be divided by the gap G and discontinuous. The gap G is formed of a material for forming the under cladding layer 1 or the over cladding layer 3. The width d of the gap G exceeds 0 (zero), and is usually set to 20 μm or less. Similarly, as shown in FIGS. 6C and 6D, two intersecting directions (two directions facing each other in FIG. 6C and two adjacent directions in FIG. 6D) are discontinuous. As shown in FIG. 6 (e), the three intersecting directions may be discontinuous, or as shown in FIG. 6 (f), all the four intersecting directions may be discontinuous. It may be discontinuous. Furthermore, a lattice shape including two or more kinds of intersections among the intersections shown in FIGS. That is, in the present invention, the “lattice shape” formed by the plurality of linear cores 2 means that a part or all of the intersections are formed as described above.

In particular, as shown in FIGS. 6B to 6F, if at least one crossing direction is discontinuous, the light crossing loss can be reduced. That is, as shown in FIG. 7 (a), in an intersection where all four intersecting directions are continuous, if one of the intersecting directions (upward in FIG. 7 (a)) is noted, the light incident on the intersection Part of the light reaches the wall surface 2a of the core 2 orthogonal to the core 2 through which the light has traveled, and the incident angle at the wall surface is smaller than the critical angle, and thus passes through the core 2 [FIG. )) Such transmission of light also occurs in the direction opposite to the above (downward in FIG. 7A). On the other hand, as shown in FIG. 7B, when one intersecting direction (the upward direction in FIG. 7B) is discontinuous by the gap G, the interface between the gap G and the core 2 is Part of the light formed and transmitted through the core 2 in FIG. 7A is reflected at the interface without transmitting through the interface because the incident angle at the interface is larger than the critical angle. Continue to advance the core 2 (see the two-dot chain arrow in FIG. 7B). From this, as described above, if at least one intersecting direction is discontinuous, the light crossing loss can be reduced. As a result, it is possible to increase the detection sensitivity of the pressed position by the pen tip or the like.

Next, examples will be described together with comparative examples. However, the present invention is not limited to the examples.

[Formation material of under clad layer and over clad layer]
Component a: 60 parts by weight of an epoxy resin (Mitsubishi Chemical Corporation YL7410).
Component b: 40 parts by weight of epoxy resin (manufactured by Daicel, EHPE3150).
Component c: 4 parts by weight of a photoacid generator (manufactured by Sun Apro, CPI101A).
By mixing these components a to c, materials for forming the under cladding layer and the over cladding layer were prepared.

[Core forming material]
Component d: 90 parts by weight of an epoxy resin (manufactured by Daicel Corporation, EHPE3150).
Component e: 10 parts by weight of an epoxy resin (manufactured by Mitsubishi Chemical Corporation, Epicoat 1002).
Component f: 1 part by weight of a photoacid generator (manufactured by ADEKA, SP170).
Component g: 50 parts by weight of ethyl lactate (manufactured by Wako Pure Chemical Industries, Ltd., solvent).
A core forming material was prepared by mixing these components d to g.

[Production of first to fourth optical waveguides]
First, an under clad layer was formed by spin coating using the under clad layer forming material. The thickness of this under cladding layer was 25 μm. The elastic modulus was 240 MPa and the refractive index was 1.496. The elastic modulus was measured using a viscoelasticity measuring device (TA instruments Japan Inc., RSA3).

Next, a plurality of linear cores were patterned on the surface of the under cladding layer by the photolithography method using the core forming material according to each optical waveguide. The core had a width of 100 μm and a thickness of 50 μm. The size of the grid-shaped core region (input region) of the first optical waveguide is 210 mm long × 297 mm wide, and the width of the gap between adjacent parallel linear cores in the region is 500 μm. It was. The elastic modulus was 1.58 GPa and the refractive index was 1.516.

Next, an over clad layer was formed on the surface of the under clad layer by spin coating using the over clad layer forming material so as to cover the core pattern member. The thickness of this over clad layer (thickness from the surface of the core) was 40 μm. The elastic modulus was 240 MPa and the refractive index was 1.496. In this way, sheet-like first to fourth optical waveguides [see FIGS. 2A, 2B and 3] were produced.

(Production of light reflecting member)
One side surface of a stainless steel rod having a rectangular cross section was cut and polished to form a groove on the side surface. The side wall of the groove was formed on an inclined surface inclined 45 ° [see FIG. 1 (b)]. The height of the light reflecting member was 6 mm, and the width was 10 mm provided on the third optical waveguide side and 5 mm provided on the second and fourth optical waveguide sides.

[Production of position sensor]
Light emitting elements (Optowell, XH85-S0603-2s) are connected to the first optical waveguide and the second optical waveguide, respectively, and light receiving elements (Hamamatsu Photonics) are connected to the third optical waveguide and the fourth optical waveguide, respectively. S10226) manufactured by the company was connected. Then, the second to fourth optical waveguides are provided on the back surface side of the three side edge portions of the first optical waveguide [see FIG. 1B], and the light reflecting member is provided on the end surfaces of the three locations. Provided.

[Comparative Example]
In the above embodiment, a comparative example is as if the second to fourth optical waveguides were directly connected to the first optical waveguide and spread on a plane (see FIG. 5).

As a result, the outer width of the three side edge portions of the first optical waveguide where the second to fourth optical waveguides are provided is the width of the light reflecting member in the embodiment, Was 5 mm, and one portion in between was 10 mm. On the other hand, in the comparative example, the width is the width of the second to fourth optical waveguides, and the two places on both sides are 47.5 mm and 35.5 mm, and one place between them is 60.0 mm. From this, it can be seen that the above embodiment is space-saving.

In the above embodiments, specific forms in the present invention have been described. However, the above embodiments are merely examples and are not construed as limiting. Various modifications apparent to those skilled in the art are contemplated to be within the scope of this invention.

The position sensor of the present invention can be used for space saving.

W1 1st optical waveguide W2 2nd optical waveguide W3 3rd optical waveguide W4 4th

optical waveguide

2, 2r Core 4 Light emitting element 5 Light receiving element 6 Light reflecting member

Claims

A sheet-like optical waveguide comprising a plurality of linear cores formed in a lattice shape and two clad layers sandwiching the lattice-shaped core;
A light emitting element for supplying light into the lattice-like core of the optical waveguide;
A light receiving element that receives the supplied light through the core;
A linear core for connecting elements, which is provided on the back side of the optical waveguide and communicates with the lattice-like core on the front side;
A light reflecting member provided on the sheet-like end face of the optical waveguide, which reflects light and allows light propagation between the lattice-like core on the front surface side and the linear core on the back surface side; A position sensor comprising:
The light emitting element or the light receiving element is connected to the linear core on the back side,
A position sensor characterized in that a surface portion of the position sensor corresponding to the lattice-shaped core is used as an input region, and a pressing position in the input region is specified by a light propagation amount of the core changed by the pressing.
The light reflecting member is made of either metal or resin, and reflects light arriving from any one of the lattice-like core on the front surface side and the linear core on the back surface side so as to reflect the light on the optical waveguide. The first inclined surface that passes along the thickness direction of the end surface and the other surface of the lattice core on the surface side and the linear core on the back surface side by further reflecting light along the thickness direction of the end surface The position sensor according to claim 1, further comprising a second inclined surface leading to the side core.
The position sensor according to claim 2, wherein the first and second inclined surfaces are light reflecting surfaces for converting an optical path by 90 °.