JP2016045771A - Position sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position sensor that saves space.SOLUTION: A position sensor includes a sheet-like optical waveguide W obtained by sandwiching a sheet-like core pattern member, which has a grid portion 2A comprising a plurality of linear cores 2 and a peripheral portion 2B extended from the cores 2 of the grid portion 2A and located along the outer periphery of the grid portion 2A, between an under-cladding layer 1 and an over-cladding layer 3. A surface portion of the over-cladding layer 3 corresponding to the grid portion 2A of the core pattern member is an input area 3A. At least a portion of a peripheral portion F of the optical waveguide W corresponding to the peripheral portion 2B of the core pattern member is folded back to the back side of the optical waveguide W.SELECTED DRAWING: Figure 2

Description

  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. 6, 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-shaped 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. The 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 the light receiving element 15 is connected to the other end face thereof. In the position sensor, both the light emitting element 14 and the light receiving element 15 are provided on the same one end edge (lower end edge in FIG. 6) of the rectangular sheet-shaped optical waveguide W1, and the light emitting element 14 is one end portion of the end edge. (The left end portion in FIG. 6), and the light receiving element 15 is disposed at the other end portion of the end edge (the right end portion in FIG. 6).

  In the position sensor, the surface portion of the over clad layer 13 corresponding to the lattice-like portion 12A of the core pattern member (a rectangular portion indicated by a one-dot chain line in the center of FIG. 6) is an input region 13A of the position sensor. Further, a portion (a portion around the input region 13A) sandwiching the outer peripheral portion 12B of the core pattern member 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 W1. It is a part (frame part) F1.

  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 detection level of light at the light receiving element 15 is lowered, so that the pressing position can be detected.

Japanese Patent No. 5513656

  In general, this type of position sensor is said to be 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 F1 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 F1. 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, the position sensor of the present invention is a breakthrough of conventional common sense, and is formed by extending a lattice-shaped portion composed of a plurality of linear cores and the core of the lattice-shaped portion. A sheet-like optical waveguide having a sheet-like core pattern member sandwiched between two sheet-like clad layers, and an outer circumferential portion arranged along the outer circumference of the lattice-like portion; A light emitting element connected to one end face of the core and a light receiving element connected to the other end face of the core in the outer peripheral portion, and the light emitted by the light emitting element passes through the core of the optical waveguide and receives the light receiving element. A position sensor that receives light by the element and uses the surface portion of the core pattern member corresponding to the lattice-shaped portion of the core pattern member as an input region, and specifies a pressing position in the input region based on the amount of light propagation of the core changed by the pressing. Ah Te, at least a part of the peripheral edge portion of the optical waveguide corresponding to the outer peripheral portion of the core pattern member, a configuration that is bent on the back side of the optical waveguide.

  In the position sensor of the present invention, the core is patterned into a lattice-like portion and an outer peripheral portion arranged along the outer periphery thereof, and the surface of the core sensor corresponds to the lattice-like portion of the core pattern member. The part is an input area. And at least one part of the peripheral part of the optical waveguide corresponding to the outer peripheral part of the said core pattern member is bend | folded to the back surface side of the optical waveguide. Therefore, the position sensor of the present invention is space-saving by the amount of the bent peripheral portion.

  In particular, when the tip of the bent portion is positioned on the back side of the optical waveguide corresponding to the input region, the thickness of the position sensor can be reduced.

  In addition, when the sheet-like optical waveguide is formed in a quadrangular shape, a light emitting element is disposed at two corners adjacent to the quadrangular shape, and a light receiving element is disposed at the remaining two corners, One light emitting element and one light receiving element are responsible for the longitudinal direction of the core of the lattice portion, and another light emitting element and another light receiving element are responsible for the lateral direction of the core of the lattice portion. Can be. That is, the vertical direction and the horizontal direction of the core of the lattice-like portion can be controlled separately, and the detection accuracy of the pressed position in the input area can be improved. Furthermore, the light propagation distance from the light emitting element to the lattice portion and the light propagation distance from the lattice portion to the light receiving element can be shortened, and the light propagation efficiency can be improved.

It is a top view showing typically one embodiment of a position sensor of the present invention. (A) is a top view which shows typically the preparation process of the said position sensor, (b) is an expanded sectional view of the center part, (c) is an expanded sectional view of the side edge part is there. It is an expanded sectional view of the side edge part which shows other embodiments of the position sensor of the present invention typically. (A)-(f) is an enlarged plan view which shows typically the cross | intersection form of the core of the lattice-like part in the said 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 is a plan view showing an embodiment of the position sensor of the present invention. The position sensor of this embodiment has three peripheral portions F of the substantially rectangular sheet-shaped optical waveguide W shown in a plan view in FIG. 2A (left and right sides and lower side in FIG. 2A). The optical waveguide W is bent on the back side. Thereby, space saving of the position sensor is achieved. In FIG. 2A, the three portions indicated by the two-dot chain line of the peripheral portion F are portions that are hidden behind the optical waveguide W by the bending and are not visible in plan view.

  That is, the position sensor according to this embodiment includes a substantially rectangular sheet-shaped optical waveguide W and two light emitting elements disposed at two adjacent corners of the optical waveguide W, as shown in FIG. An element 4 and two light receiving elements 5 disposed at the remaining two corners of the optical waveguide W are provided. A rectangular portion at the center of the surface of the optical waveguide W [a quadrangular portion indicated by a one-dot chain line in FIG. 2A] is an input region 3A, and FIG. 2B (enlarged sectional view of the central portion of the position sensor). As shown in FIG. 3, an electric circuit board E is provided on the back surface portion of the optical waveguide W corresponding to the input region 3A. Of the four peripheral portions (frame portions) F of the optical waveguide W around the input region 3A, the peripheral portions F at the three locations (the left and right sides and the lower side in FIG. 2A) are shown in FIG. 2 (c) (enlarged sectional view of the side edge portion of the position sensor), it is bent. The bent front end of the peripheral portion F is brought into contact with an electric circuit forming surface of the electric circuit board E (a surface opposite to the optical waveguide W: a lower surface in FIG. 2C), and the light emitting element 4 and the light receiving element 5 are mounted on the electric circuit forming surface of the electric circuit board E. In this embodiment, the peripheral portion F at one portion that is not bent (the upper side in FIGS. 1 and 2A) is formed narrow in advance so that it does not need to be bent.

  More specifically, the optical waveguide W includes a lattice-shaped portion 2A composed of a plurality of linear optical path cores 2 on the surface of the substantially quadrilateral sheet-like underclad layer 1, and the core 2 of the lattice-shaped portion 2A. A sheet-like core pattern member is formed which includes an outer peripheral portion 2B extending from the outer periphery of the lattice-shaped portion 2A and covering the core pattern member. An over clad layer 3 is formed on the surface of the layer 1. And the surface part of the over clad layer 3 corresponding to the lattice-like part 2A of the core pattern member is the input region 3A. Further, a portion where the outer peripheral portion 2B of the core pattern member is sandwiched between the side edge portion of the under cladding layer 1 and the side edge portion of the over cladding layer 3 is a peripheral portion (frame portion) F of the optical waveguide W. Yes. In FIG. 1 and FIG. 2A, the core 2 is indicated by a chain line, and the thickness of the chain line indicates the thickness of the core 2. In FIG. 1 and FIG. 2A, the number of cores 2 is omitted. The arrows in FIGS. 1 and 2 (a) indicate the light traveling direction.

  Further, in this embodiment, one light emitting element 4 is connected to one end face of the core 2 of the outer peripheral portion 2B in which the longitudinal core 2 of the lattice-like portion 2A of the core pattern member is extended. One light receiving element 5 is connected to the other end face, and another light emitting element 4 is connected to one end face of the core 2 of the outer peripheral part 2B in which the horizontal core 2 of the lattice-like part 2A extends. Then, another light receiving element 5 is connected to the other end face thereof. 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. It is designed to receive light.

  In this way, by connecting the light emitting element 4 and the light receiving element 5 in the vertical direction and the horizontal direction (XY direction) of the grid-like portion 2A, the two directions can be controlled separately, and the input region The detection accuracy of the pressed position in 3A can be improved. Furthermore, as described above, since the light emitting element 4 or the light receiving element 5 is disposed at each corner of the substantially rectangular sheet-shaped optical waveguide W, the light from the light emitting element 4 to the lattice-shaped portion 2A. The propagation distance and the light propagation distance from the lattice-like portion 2A to the light receiving element 5 can be shortened, and the light propagation efficiency can be improved.

  The electric circuit board E is provided on the back surface (surface opposite to the core formation surface) of the under cladding layer 1 of the optical waveguide W corresponding to the input region 3A. As described above, the tip of the peripheral portion F of the bent optical waveguide W is formed on the electric circuit forming surface of the electric circuit board E [the under cladding layer as shown in FIG. The light emitting element 4 and the light receiving element 5 are mounted on the electric circuit forming surface of the electric circuit board E. The surface opposite to the surface 1 is the lower surface in FIG. Here, the thickness of the electric circuit board E is set within a range of 1 to 10 mm, for example, and the bending radius (inner diameter) R of the bent portion is set within a range of 0.5 to 5 mm, for example. . If the bending radius R is too small, the light propagation efficiency at the bent portion tends to be reduced. If it is too large, the protruding width (frame width) T of the bent portion protruding around the input region 3A is large. Therefore, the effect of space saving of the position sensor tends to be reduced.

  Input of characters or the like to the position sensor is performed by writing 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 detection level of light at the light receiving element 5 is lowered, so that the pressing position (XY coordinate) can be detected.

  In the manufacturing method of the position sensor, first, the optical waveguide W and the electric circuit board E are individually manufactured. Next, the back surface portion of the under cladding layer 1 of the optical waveguide W corresponding to the input region 3A is brought into contact with the surface of the electrical circuit board E opposite to the electrical circuit formation surface. Next, the light emitting element 4 and the light receiving element 5 are connected to the end face of the core 2 of the optical waveguide W. The peripheral portion F of the optical waveguide W is bent at a right angle with respect to the core 2 of the peripheral portion F, and the tip of the bent peripheral portion F is brought into contact with the electric circuit forming surface of the electric circuit board E. The light emitting element 4 and the light receiving element 5 are mounted on the electric circuit forming surface. In this way, the position sensor can be obtained.

  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 thickness of each layer is set, for example, such that the under cladding layer 1 is in the range of 10 to 500 μm, the core 2 is in the range of 5 to 100 μm, and the over cladding layer 3 is in the range of 1 to 200 μm. 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.

  The elastic modulus of the core 2 is preferably 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 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 the detection level of light at the light receiving element 5 [see FIG. 2A] decreases in the core 2, so that the pressed position is detected. be able to.

  Further, from the viewpoint of preventing light from leaking from the core 2, the refractive index of the core 2 is set larger than the refractive indexes of the under cladding layer 1 and the over cladding layer 3. In particular, in the bent portion, light may leak from the core 2 to the outside of the bend (on the over clad layer 3 side) due to the bend. Therefore, by setting the refractive index of the over clad layer 3 to be smaller, It is preferable to make the difference in refractive index from 2 larger to make it difficult for light to leak. The elastic modulus and refractive index can be adjusted by, for example, selecting the type of each forming material and adjusting the composition ratio.

  FIG. 3 is an enlarged sectional view showing a side edge portion of another embodiment of the position sensor of the present invention. In this embodiment, in the above-described embodiment shown in FIGS. 1 and 2A to 2C, the bent portion of the peripheral portion F of the optical waveguide W is bent 90 ° to the back side of the optical waveguide W. It has become a thing. Correspondingly, the electric circuit board E is also bent by 90 °. Other parts are the same as those in the above-described embodiment shown in FIGS. 1 and 2A to 2C, and the same reference numerals are given to the same parts.

  In this embodiment as well, as in the above-described embodiment shown in FIGS. 1 and 2A to 2C, space saving in a plan view of the position sensor can be achieved. Further, the position sensor of this embodiment can be installed at a corner of a desk or the like along the inside of the portion bent by 90 °.

  In each of the above embodiments, three of the four peripheral portions F of the optical waveguide W are bent. However, other portions may be used. For example, all four portions may be bent or two portions may be bent. It is good or you may bend only one place.

  In each of the above embodiments, two light emitting elements 4 and two light receiving elements 5 are used. However, other light emitting elements 4 and light receiving elements 5 may be used. For example, one light emitting element 4 or three or more light receiving elements 5 may be used. In the above embodiment, the light emitting element 4 or the light receiving element 5 is disposed at each corner of the substantially rectangular sheet-shaped optical waveguide W. However, for example, all of the light emitting element 4 and the light receiving element 5 are provided. Alternatively, they may be disposed at the same end edge of the substantially rectangular sheet-shaped optical waveguide W.

  Furthermore, in each of the above-described embodiments, each crossing portion of the core 2 of the lattice-like portion is usually formed in a state in which all four intersecting directions are continuous as shown in the enlarged plan view in FIG. Others are acceptable. For example, as shown in FIG. 4B, 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. 4C and 4D, two intersecting directions [FIG. 4C is two opposing directions, and FIG. 4D is two adjacent directions] are discontinuous. As shown in FIG. 4 (e), the three intersecting directions may be discontinuous, or as shown in FIG. 4 (f), all the four intersecting directions may be discontinuous. It may be discontinuous. Furthermore, it is good also as a grid | lattice shape provided with the 2 or more types of cross | intersection part of the said cross | intersection part shown to Fig.4 (a)-(f). 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. 4B to 4F, when at least one intersecting direction is discontinuous, the light crossing loss can be reduced. That is, as shown in FIG. 5 (a), in an intersection where all four intersecting directions are continuous, if one of the intersecting directions [upward in FIG. 5 (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 is transmitted through the core 2 because the reflection angle at the wall surface is large [two points in FIG. (See chain line arrow). Such transmission of light also occurs in the direction opposite to the above (downward in FIG. 5A). On the other hand, as shown in FIG. 5B, when the intersecting one direction [upward in FIG. 5B] is discontinuous by the gap G, the interface between the gap G and the core 2 is A part of the light formed and transmitted through the core 2 in FIG. 5 (a) is reflected at the interface without passing through the core 2 because the reflection angle at the interface is small, and continues to travel through the core 2 [FIG. (Refer to the arrow of the two-dot chain line in 5 (b)). 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-cladding layer was formed on the surface of the under-cladding layer by spin coating using the over-cladding 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]
Prepare an electric circuit board having the same dimensions as the input region, with an electric circuit formed on one side, and on the surface opposite to the electric circuit forming surface, the back surface of the under cladding layer of the optical waveguide corresponding to the input region The parts were brought into contact. Next, a light emitting element (Optowell, XH85-S0603-2s) is connected to one end face of the outer peripheral core, and a light receiving element (Hamamatsu Photonics, s10226) is connected to the other end face of the outer peripheral core. Connected. Then, the peripheral portions of the three portions of the optical waveguide were bent and brought into contact with the electric circuit forming surface of the electric circuit board, and the light emitting element and the light receiving element were mounted on the electric circuit forming surface. In the bending, the protruding width of the bent portion protruding around the input region was 10 mm at two positions on both sides, and 5 mm at one position between them, and the bending radius was 2 mm. In this case, the widths of the peripheral portions of the three bent portions were 47.5 mm and 35.5 mm at two locations on both sides, and 60.0 mm at one location therebetween.

[Comparative Example]
In the above embodiment, a comparative example is one in which the peripheral portion of the optical waveguide is not bent.

  Comparing the above example and the comparative example, it can be seen that the above example is space-saving by the amount of bending of the peripheral portion.

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

W Optical waveguide F Peripheral part 1 Under clad layer 2 Core 2A Grid-like part 2B Peripheral part 3 Over clad layer 3A Input region

Claims (3)

  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 sheet-like optical waveguide sandwiched between two sheet-like clad layers, a light-emitting element connected to one end face of the core in the outer peripheral part, and a light-receiving element connected to the other end face of the core in the outer peripheral part The light emitted by the light emitting element is received by the light receiving element through the core of the optical waveguide, and the surface portion of the core pattern member corresponding to the lattice portion of the core pattern member is used as an input region. A position sensor that specifies a pressing position in the input region by a light propagation amount of a core changed by the pressing, and at least a part of a peripheral portion of the optical waveguide corresponding to an outer peripheral portion of the core pattern member is A position sensor, characterized in that bent on the back side of the waveguide.   The position sensor according to claim 1, wherein a tip of the bent portion is positioned on a back surface side of the optical waveguide corresponding to the input region.   3. The sheet-like optical waveguide is formed in a quadrangular shape, light emitting elements are arranged at two adjacent corners of the quadrangular shape, and light receiving elements are arranged at the remaining two corners. Position sensor.

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