WO2016043048A1

WO2016043048A1 - Position sensor

Info

Publication number: WO2016043048A1
Application number: PCT/JP2015/074904
Authority: WO
Inventors: 良真吉岡; 裕介清水; 柴田　直樹
Original assignee: 日東電工株式会社
Priority date: 2014-09-16
Filing date: 2015-09-02
Publication date: 2016-03-24
Also published as: JP2016062159A; TW201614457A

Abstract

Provided is a position sensor with which the difference between the spectral intensities, in the vertical and horizontal directions, of light propagating through a lattice core can be easily reduced. This position sensor is provided with: a substantially rectangular sheet-like optical waveguide (W) having a sheet-like core pattern member provided with a lattice section (2A) comprising a plurality of linear cores (2), and an outer peripheral section (2B) which extends from each of the cores (2) of the lattice section (2A), and which is disposed along the outer periphery of the lattice section (2A); two light-emission elements (4); and two light-reception elements (5). One end surface and another end surface of the core (2) of the outer peripheral section (2B) from which the vertical-direction cores (2) of the lattice section (2A) extend, and one end surface and another end surface of the core (2) of the outer peripheral section (2B) from which the horizontal-direction cores (2) of the lattice section (2A) extend are positioned at one side of the rectangular shape of the optical waveguide (W). The one end surfaces of the two cores (2) of the outer peripheral section (2B) respectively have one of the light-emission elements (4) connected thereto. The other end surfaces of the two cores (2) of the outer peripheral section (2B) respectively have one of the light-reception elements (5) connected thereto.

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. 4, this has a rectangular sheet-shaped optical waveguide W <b> 1 in which a sheet-shaped core pattern member is sandwiched between a rectangular sheet-like under cladding layer 11 and an over cladding 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. 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 through the lattice portion 12A and the outer peripheral portion 12B on the opposite side. It is designed to receive light. A surface portion of the over clad layer 13 corresponding to the lattice portion 12A (a rectangular portion indicated by a one-dot chain line in the center of FIG. 4) is an input region 13A of the position sensor.

When inputting, the input area 13A is pressed with, for example, an input pen tip. Thereby, 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, in this type of position sensor, a light emitting element and a light receiving element are mounted on an electric circuit board. From the viewpoint of reducing the manufacturing cost by making the electric circuit board as compact as possible, the light emitting element and the light receiving element are combined. It is common technical knowledge to place them close together. In fact, in the position sensor shown in FIG. 4, both the light emitting element 14 and the light receiving element 15 are provided on one side (the lower end side in FIG. 4) of the rectangular sheet-shaped optical waveguide W <b> 1. Are placed close together.

In general, in this type of position sensor, it is common technical knowledge to reduce the number of light emitting elements and light receiving elements as much as possible from the viewpoint of manufacturing cost. In fact, one position sensor is used in each of the position sensors shown in FIG.

And in order to detect a press position appropriately, in the lattice-like part 12A of the core pattern member, the spectral intensity of the propagating light is made substantially equal between the vertical core 12 and the horizontal core 12, It is necessary to make the difference small. Therefore, the arrangement and the like of the core 12 of the outer peripheral portion 12B are designed so as to be so. However, the spectral intensity of the light may differ greatly between the vertical direction and the horizontal direction due to variations in the quality of the forming material such as the core 12 and variations in dimensions during the manufacturing process. If the difference in spectral intensity of the light exceeds the allowable range, the pressed position may not be detected properly. In that case, the vertical and horizontal spectral intensities are adjusted by redesigning the arrangement of the core 12 in the outer peripheral portion 12B of the core pattern member, and the difference is made within an allowable range.

However, the redesign and the like require a cost. In addition, as described above, from the viewpoint of manufacturing cost, the arrangement of the light emitting element 14 and the light receiving element 15 is limited, and therefore there is a limit to the device for arranging the core 12 of the outer peripheral portion 12B. Therefore, it takes time to adjust the vertical and horizontal spectral intensity. In these respects, the position sensor has room for improvement.

The present invention has been made in view of such circumstances, and provides a position sensor capable of easily reducing the difference between the vertical direction and the horizontal direction of the spectral intensity of light propagating through the lattice-shaped core. Is the purpose.

In order to achieve the above object, the position sensor of the present invention has a lattice-shaped portion composed of a plurality of linear cores, and extends along the outer periphery of the lattice-shaped portion extending from the core of the lattice-shaped portion. A substantially rectangular sheet-shaped optical waveguide sandwiched between two sheet-shaped clad layers with a sheet-shaped core pattern member having an outer peripheral portion disposed, and a light emitting element and a light receiving element connected to the core of the optical waveguide A position sensor including an element, wherein one end surface and the other end surface of a core in an outer peripheral portion where a longitudinal core of the lattice portion is extended, and a lateral core of the lattice portion is extended. One end face and the other end face of the core in the outer peripheral portion are positioned on one side of the rectangular shape of the substantially rectangular sheet-shaped optical waveguide, and one light emitting element is connected to each of the two end faces of the core in the outer peripheral portion. The outer circumference One light receiving element is connected to each of the two other end surfaces of the core, and light emitted from the light emitting element is received by the light receiving element through the core of the optical waveguide, and the core pattern member The surface portion of the position sensor corresponding to the lattice portion is used as an input region, and the pressing position in the input region is specified by the light propagation amount of the core changed by the pressing.

In other words, the position sensor of the present invention breaks down the conventional common sense, and even if the manufacturing cost is sacrificed, priority is given to the detection of the pressed position, and two light emitting elements and two light receiving elements are used. Yes. And, one light emitting element is connected to one end face of the core of the outer peripheral part where the longitudinal core of the lattice-like part is extended, and one light receiving element is connected to the other end face of the core, The remaining one light-emitting element is connected to one end face of the core in the outer peripheral part where the horizontal core of the grid-like part is extended, and the remaining one light-receiving element is connected to the other end face of the core. ing. Thereby, in the lattice-like portion of the core pattern member, the spectral intensity of light can be individually adjusted in the vertical direction and the horizontal direction, the difference between the two is reduced, and the detectability of the pressed position is improved. This eliminates the need for redesign or the like when the difference in spectral intensity of the light is large, and the cost can be reduced accordingly. As a result, the sacrificed manufacturing cost can be recovered.

In the position sensor of the present invention, two light emitting elements and two light receiving elements are used, respectively, and one light emitting element is provided on one end face of the core in the outer peripheral portion where the longitudinal core of the lattice-like portion is extended. One light-receiving element is connected to the other end face of the core, and the remaining one light-emitting element is attached to one end face of the core in the outer peripheral part where the horizontal core of the lattice-like part is extended. The remaining one light receiving element is connected to the other end face of the core. Therefore, the spectral intensity of the light propagating through the core of the lattice portion can be individually adjusted in the vertical direction and the horizontal direction of the lattice portion. As a result, even if a difference in the spectral intensity of light occurs between the vertical direction and the horizontal direction, the difference can be easily reduced, and the pressed position can be detected appropriately. Further, one end surface and the other end surface of the outer peripheral portion where the longitudinal core of the lattice-like portion is extended, and one end surface of the outer peripheral portion core where the lateral core of the lattice-like portion is extended, and Since the other end face is positioned on one side of the rectangular shape of the substantially rectangular sheet-shaped optical waveguide, the two light-emitting elements and the light-receiving elements are connected to the core from the two light-emitting elements and the light-receiving elements. It is arranged on one side of the rectangular shape of the optical waveguide. Therefore, these elements are arranged at positions close to each other. For this reason, even if the number of elements is increased, the electric circuit board on which the elements are mounted can be made compact, and the manufacturing cost can be suppressed. In addition, when widening the input area or improving the detection accuracy of the pressed position in the input area, it is necessary to increase the number of cores, but because two light emitting elements and two light receiving elements are used, The increase in the number of cores can be easily accommodated without weakening the spectral intensity of light propagating through the core.

(A) is a top view which shows typically one Embodiment of the position sensor of this invention, (b) is an expanded sectional view of the center part. (A) to (f) are enlarged plan views schematically showing the crossing form of the cores of the lattice-like portion 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 core of the said lattice-shaped part. 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 the cross section of the central portion thereof. The position sensor of this embodiment includes a substantially rectangular sheet-shaped optical waveguide W and two light-

emitting elements

4 and 2 arranged on one side of the optical waveguide W (the lower side in FIG. 1A). Light receiving elements 5. In this position sensor, the number of the

elements

4 and 5 is a major feature of the present invention.

The optical waveguide W is extended on the surface of the substantially quadrilateral sheet-like under cladding layer 1 from a lattice portion 2A composed of a plurality of linear optical path cores 2 and the core 2 of the lattice portion 2A. A sheet-like core pattern member provided with an outer peripheral portion 2B arranged along the outer periphery of the lattice-like portion 2A is formed, and the surface of the under-cladding layer 1 is covered with the core pattern member. The over clad layer 3 is formed. Then, one end face and the other end face of the core 2 of the outer peripheral portion 2B where the longitudinal core 2 of the lattice-like portion 2A extends, and an outer peripheral portion where the horizontal core 2 of the lattice-like portion 2A extends. One end surface and the other end surface of the core 2 of 2B are positioned on one side of the substantially rectangular sheet-shaped optical waveguide W [lower side in FIG. 1A]. In FIG. 1A, the core 2 is indicated by a chain line, the thickness of the chain line indicates the thickness of the core 2, and the number of the cores 2 in the lattice-like portion 2A is omitted. Moreover, the arrow of Fig.1 (a) has shown the direction where light travels.

Then, one light emitting element 4 is connected to one end surface of the core 2 of the outer peripheral portion 2B where the longitudinal core 2 of the lattice-shaped portion 2A of the core pattern member is extended, and the other end surface of the core 2 is connected to the other end surface of the core 2 One light-receiving element 5 is connected, and the remaining one light-emitting element 4 is connected to one end surface of the core 2 of the outer peripheral part 2B in which the horizontal core 2 of the lattice-like part 2A extends. The remaining one light receiving element 5 is connected to the other end surface of the core 2. In such a position sensor, the light emitted from the light emitting element 4 passes through the core 2 through the outer peripheral part 2B on the opposite side from the outer peripheral part 2B connected to the light emitting element 4 through the lattice part 2A. The light receiving element 5 receives light. The surface portion of the over clad layer 3 corresponding to the lattice-like portion 2A of the core pattern member [rectangular portion indicated by a one-dot chain line in the center of FIG. 1A] is an input region 3A.

As described above, the position sensor uses two light emitting elements 4 and two light receiving elements 5, respectively. As described above, the vertical direction and the horizontal direction of the lattice-shaped portion 2A (two directions ( The light emitting element 4 and the light receiving element 5 are connected to each other (XY direction). Therefore, the light in these two directions can be individually controlled. As a result, even if a difference in the spectral intensity of light occurs between the vertical direction and the horizontal direction, the difference can be easily reduced, and the pressed position can be detected appropriately. The difference in spectral intensity is preferably 1 dB or less.

Furthermore, although the light emitting element 4 and the light receiving element 5 are used two by two, and the number of the light emitting elements 4 and the light receiving elements 5 is larger than that of the conventional position sensor (see FIG. 4), the

elements

4 and 5 are substantially rectangular sheet-shaped light guides They are arranged on one side of the rectangular shape of the waveguide W and are close to each other. Therefore, even if the number of the

elements

4 and 5 increases, the electric circuit board (not shown) on which the

elements

4 and 5 are mounted can be made compact, and the manufacturing cost can be suppressed.

In addition, when the input area 3A of the position sensor is widened or the detection accuracy of the pressed position in the input area 3A is improved, it is necessary to increase the number of cores 2. In the position sensor, the light emitting element 4 and two light receiving elements 5 are used, respectively, and the increase in the number of cores 2 can be easily accommodated without weakening the spectral intensity of light propagating through the cores 2. That is, the position sensor can easily cope with the enlargement of the input area 3A and the improvement of the detection accuracy of the pressed position.

Then, the input of characters or the like to the position sensor is performed by writing the characters or the like in the input area 3A directly or via a resin film or paper with an input body such as a pen. 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. Therefore, in the core 2 of the pressing portion, the light receiving level at the light receiving element 5 is lowered, so that the pressing position (XY coordinate) can be detected.

In the optical waveguide W, the elastic modulus of the core 2 is preferably set to be 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 optical waveguide W is recessed by the pressing, and therefore corresponds to the recessed portion. Light leakage (scattering) occurs from the bent portion of the core 2, and in the core 2, the light receiving level at the light receiving element 5 decreases, so that the pressed position can be detected.

Examples of the material for forming the under cladding layer 1, the core 2 and the over cladding layer 3 include a photosensitive resin, a thermosetting resin, and the like, and the optical waveguide W can be manufactured by a manufacturing method corresponding to the forming material. . The refractive index of the core 2 is 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 core 2, 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.

Furthermore, in the above-described embodiment, each of the intersecting portions of the core 2 of the lattice-shaped portion 2A is normally formed in a state in which all of the four intersecting directions are continuous, as shown in an enlarged plan view in FIG. Others are acceptable. For example, as shown in FIG. 2B, 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. 2 (c) and 2 (d), two intersecting directions (two opposing directions in FIG. 2 (c) and two adjacent directions in FIG. 2 (d)) are discontinuous. As shown in FIG. 2 (e), the three intersecting directions may be discontinuous, or as shown in FIG. 2 (f), all the four intersecting directions may be discontinuous. It may be discontinuous. Furthermore, a lattice shape having two or more types of intersections among the above-described 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. 2B to 2F, if at least one intersecting direction is discontinuous, the light crossing loss can be reduced. That is, as shown in FIG. 3 (a), in an intersection where all four intersecting directions are continuous, if one of the intersecting directions (upward in FIG. 3 (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, so that the light passes through the core 2 [FIG. )) Such transmission of light also occurs in the direction opposite to the above (downward in FIG. 3A). On the other hand, as shown in FIG. 3 (b), when one intersecting direction (upward in FIG. 3 (b)) is discontinuous by the gap G, the interface between the gap G and the core 2 is Part of the light that is formed and passes through the core 2 in FIG. 3 (a) is reflected at the interface without passing through the interface because the incident angle at the interface is larger than the critical angle. Continue to advance through the core 2 (see the two-dot chain arrow in FIG. 3B). 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 optical waveguide]
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 sheet-like core pattern member having a lattice-shaped portion composed of a plurality of linear cores and an outer peripheral portion is formed on the surface of the under-cladding layer by the photolithography method using the core forming material. did. The size of the grid portion (input area) was 210 mm long × 297 mm wide. The width of the core was 100 μm, the thickness was 50 μm, and the width of the gap between adjacent parallel linear cores in the lattice portion was 500 μm. 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, a sheet-like optical waveguide was produced.

[Production of position sensor]
Two light emitting elements (manufactured by Optowell, XH85-S0603-2s) and two light receiving elements (manufactured by Hamamatsu Photonics, s10226) were prepared. And one light emitting element is connected to one end face of the core of the outer peripheral part where the longitudinal core of the lattice-like part of the core pattern member is extended, and one light receiving element is connected to the other end face of the core. And connecting the remaining one light-emitting element to one end face of the core of the outer peripheral portion where the lateral core of the lattice-like portion is extended, and connecting the remaining one light-emitting element to the other end face of the core A light receiving element was connected [see FIG. 1 (a)].

[Comparative Example]
In the above embodiment, one light emitting element and one light receiving element are provided, and one light emitting element is connected to one end face of both cores of the outer peripheral part in which the vertical direction and the horizontal direction of the lattice-shaped part are extended, One light receiving element was connected to the other end faces of the cores (see FIG. 4).

The above example and the comparative example were compared with respect to the spectral intensity of light received by the light receiving element. As a result, the difference between the vertical direction and the horizontal direction of the spectral intensity of the light of the lattice-shaped portion of the core pattern member is 1 dB in the example and 5 dB in the comparative example, and the example is smaller than the comparative example. It was.

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 to reduce the difference between the vertical direction and the horizontal direction of the spectral intensity of propagating light in the lattice-like core of the optical waveguide constituting the position sensor.

W Optical waveguide 2 Core 2A Grid-like part 2B Outer peripheral part 4 Light emitting element 5 Light receiving element

Claims

A sheet-like core pattern member comprising a lattice-shaped portion composed of a plurality of linear cores and an outer peripheral portion that extends from the core of the lattice-shaped portion and is arranged along the outer periphery of the lattice-shaped portion A substantially rectangular sheet-like optical waveguide sandwiched between two sheet-like clad layers;
A position sensor comprising a light emitting element and a light receiving element connected to the core of the outer peripheral part,
One end surface and the other end surface of the core in the outer peripheral portion where the longitudinal core of the lattice portion extends, and one end surface and the other end surface of the core in the outer peripheral portion where the lateral core of the lattice portion extends. Is positioned on one side of the substantially rectangular sheet-shaped optical waveguide,
One light emitting element is connected to each of the two end faces of the core of the outer peripheral portion,
One light receiving element is connected to each of the two other end faces of the outer peripheral core,
The light emitted from the light emitting element is received by the light receiving element through the core of the optical waveguide, and the surface portion of the position sensor corresponding to the lattice portion of the core pattern member is used as an input region. A position sensor characterized in that the pressing position in the is specified by the amount of light propagation of the core changed by the pressing.