TW201546688A - Position sensor - Google Patents

Abstract

When inputting character information or other information with an input body such as a pen, this position sensor does not detect unwanted parts such as the little finger of the hand holding the input body or the base part of said finger, but does detect desired parts, such as the pen tip, with high sensitivity. This position sensor is provided with a sheet-form optical waveguide (W) which comprises a lattice-form core held between an undercladding layer and an overcladding layer, a light emitting element which is connected to one end surface of the core, and a light receiving element which is connected to the other end surface of the core. The modulus of elasticity of the core is set to be greater than the modulus of elasticity of the undercladding layer and the overcladding layer, and projections are provided in areas on the surface of the undercladding layer opposite of the surface supporting the core, corresponding to areas of the core between adjacent intersections in the lattice-form core.

Description

Position sensor Field of invention

The present invention relates to a position sensor for optically detecting a pressing position.

Background of the invention

Heretofore, a position sensor that optically detects a pressing position has been proposed (for example, refer to Patent Document 1). The position sensor is a plurality of cores arranged to be optical paths in the longitudinal and lateral directions, and the periphery of the core is covered by the covering body to form a sheet shape, and light from the light emitting element is incident on one of the cores. The end faces, and the other end faces of the respective cores, detect light transmitted through the respective cores by the light receiving elements. Moreover, when a part of the surface of the sheet-like position sensor is pressed with a finger or the like, the core of the pressing portion is crushed (the cross-sectional area of the core in the pressing direction becomes small), at the core of the pressing portion, due to The light detecting level of the light receiving element is lowered, so that the pressed position can be detected.

Prior technical literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 8-234895

Summary of invention

In general, when writing a character or the like on a paper with a writing instrument such as a pen, the little finger of the hand holding the writing instrument or the root portion thereof (hypothenar) or the like may also contact the surface of the paper.

Therefore, when the character or the like is input by a writing instrument such as a pen on the surface of the sheet-like position sensor of the above-mentioned Patent Document 1, it is not only the tip of the pen, but also the little finger of the hand holding the writing instrument or the palm root portion thereof, and the like. The above-mentioned sheet-shaped position sensor is also pressed, so that not only the input text or the like is detected, but also an unnecessary portion such as the little finger or the palm root portion thereof is detected.

Further, in the position sensor using the optical waveguide as described above, for example, the core is easily crushed, etc., to improve the detection sensitivity of the press, the detection sensitivity of the pen tip is improved, but the grip is improved. The detection sensitivity of the portion of the hand or the root portion of the hand such as a pen that does not need to be detected is also improved.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a position sensor which does not detect a small finger or a palm of a hand holding the input body when information such as a character is input by a pen or the like. Unnecessary parts such as the root part, and high sensitivity can be used to detect the desired part such as the nib.

In order to achieve the above object, the position sensor of the present invention is a sheet-shaped position sensor having a sheet-shaped optical waveguide. a core having a plurality of linear shapes formed in a lattice shape, a lower cladding layer supporting the cores, and an upper cladding layer covering the core; the light emitting element is connected to one end surface of the core; and the light receiving element is connected to the above The other end face of the core; and the protruding portion disposed between the intersection of the lower cladding layer opposite to the surface supporting the core, and the intersection and the intersection between the adjacent lattice core a portion corresponding to the core portion, wherein the sheet-like optical waveguide is bent with the protruding portion as a fulcrum, and an elastic modulus of the core is set to be higher than an elastic modulus of the lower cladding layer and the upper cladding layer The modulus of elasticity is also large, and in the pressed state of the surface of the sheet-like optical waveguide, the deformation ratio of the core cross section in the pressing direction is smaller than the deformation ratio of the cross section of the upper cladding layer and the lower cladding layer, The change in the amount of light propagation of the core caused by the pressing of the surface of the position sensor described above is used to specify the pressing point.

Further, in the present invention, the "deformation rate" refers to the amount of change in thickness of each of the core, the upper cladding layer, and the lower cladding layer in the pressing direction with respect to each thickness before pressing. ratio.

The inventors have continued research on the light propagation of the core in which information such as characters is input to a position sensor surface having a sheet-like optical waveguide formed into a lattice shape by a plurality of linear core configurations by using an input body such as a pen When the part holding the input body is not detected. In the course of his research, the inventor thought of: instead of pressing the core (the cross-sectional area becomes smaller) with the pressure of the pen tip or the hand holding the pen as in the past, the reverse is to prevent the core from being subjected to the above pressure. Flattened (the cross-sectional area is almost unchanged). Therefore, the elastic modulus of the core is set to be larger than the elastic modulus of the lower cladding layer and the elastic modulus of the upper cladding layer. This In any case, the part of the nib and the part of the hand are deformed by the upper cladding layer and the lower cladding layer being crushed in the pressing direction, and the core is the section where the cross-sectional area is hardly changed along the nib or the part of the hand. Bend by entering the lower cladding layer. Moreover, the bending state of the core is a sharp bend in the portion of the pen tip, and a gentle curve in the portion of the hand. As a result, it can be seen that at the core of the nib portion, light from the core leaks (scatters) due to the sharp bending of the core, and at the core of the part of the hand, since the bending of the core is gentle, no such light leakage occurs ( scattering). That is, at the core of the nib portion, the light detection level (light receiving amount) of the light receiving element is lowered, and at the core of the hand portion, the detection level is not lowered. The inventors have found out that from the lowering of the light detection level, the position of the nib can be detected, and the part of the hand whose detection level is not lowered is not detected as in the unpressed state.

Then, in order to increase the sensitivity of the above-described pen tip detection, the inventors made it easier for light to leak from the core of the pen tip portion (easily scattered), and the configuration of the position sensor was repeatedly studied. As a result, it was found that a portion corresponding to the core portion between the intersection portion and the intersection portion of the lattice-shaped core adjacent to the surface of the lower cladding layer opposite to the surface supporting the core is provided. Highlights. When the protruding portion is provided in this manner, the protruding portion is in a state of supporting the sheet-like optical waveguide from below, and a cavity portion is formed between the adjacent protruding portion and the protruding portion. Therefore, when the tip portion between the adjacent protruding portion and the protruding portion of the sheet-shaped optical waveguide is pressed by the pen tip, the protruding portion is used as a fulcrum and is bent toward the cavity portion. Thereby, even if the pressing of the pen tip is only a little bit (even if the pressing is shallow), the bending of the sheet-shaped optical waveguide of the pressing portion is more urgent, and the light is easier. The ground leaks from the core of the curved portion (easily scattered). That is, the inventors have found that if the above-mentioned protruding portion is provided, the sensitivity of the press detection of the pen tip can be improved, and the present invention is completed.

The position sensor of the present invention has a core modulus which is set to be larger than the elastic modulus of the lower cladding layer and the elastic modulus of the upper cladding layer. Therefore, when the surface of the cladding layer is pressed over the sheet-shaped optical waveguide, the deformation ratio of the core cross section in the pressing direction becomes smaller than the deformation ratio of the cross section of the upper cladding layer and the lower cladding layer, and the pressing direction is small. There is almost no change in the cross-sectional area of the core. Further, when information such as characters is input on the surface of the position sensor by a pen or the like, the bending state of the core is sharply bent along the front end input portion such as the pen tip at the pressing portion of the front end input portion such as the pen tip. Leakage (scattering) from the light of the core occurs, and in the pressing portion of the portion of the hand holding the input body, the bending state of the core is a gentle state along the hand, which can cause leakage (scattering) of the above light. will not happen. Therefore, it is possible to reduce the light detection level of the light receiving element at the core pressed by the front end input unit such as the pen tip, and the detection level of the core pressed by the hand holding the input body does not decrease. Further, from the decrease in the light detection level, the position of the front end input portion such as the pen tip can be detected, and the portion of the hand whose detection level is not lowered is not detected because it is the same as the unpressed state. To.

Further, a portion corresponding to a core portion between the intersection portion and the intersection portion adjacent to the lattice-like core in a surface of the lower cladding layer opposite to the surface supporting the core is provided. The protruding portion, so when the front end of the sheet-like optical waveguide is pressed by a front end input portion such as a pen tip The portion between the protruding portion and the protruding portion is such that the pressing portion is only a little bit (even if the pressing is shallow), and the protruding portion is used as a fulcrum, so that the bending condition is more urgent, and the light can be made easier. The core of this part leaks out (more easily scattered). Therefore, the sensitivity of the press detection of the front end input portion such as the pen tip can be improved.

In particular, when the thickness of the protruding portion is set to be in the range of 10 to 200 μm, more light can be leaked (scattered) from the core of the portion pressed by the tip input portion such as the pen tip. Bending, the press detection sensitivity of the front end input portion such as the pen tip can be more appropriately improved.

1‧‧‧Under cladding

2‧‧‧ core

2a‧‧‧ wall

3‧‧‧Upper coating

4‧‧‧Lighting elements

5‧‧‧Light-receiving components

7‧‧‧Rigid board

10‧‧‧ Input body

10a‧‧‧ front-end input section

20‧‧‧ hands

d‧‧‧Width of gap G

G‧‧‧ gap

H‧‧‧The Cavity Department

T‧‧‧President

W‧‧‧Flake optical waveguide

Fig. 1 is a view schematically showing a first embodiment of a position sensor according to the present invention, wherein (a) is a plan view and (b) is an enlarged cross-sectional view of a central portion thereof.

Fig. 2 is an enlarged plan view schematically showing the core and the protruding portion of the above position sensor.

Fig. 3 is a cross-sectional view schematically showing a state of use of the position sensor, wherein (a) is a pressed state and (b) is a state in which pressing is released.

Fig. 4 is an enlarged plan view schematically showing a core and a protruding portion in a second embodiment of the position sensor of the present invention.

5(a) to 5(f) are enlarged plan views schematically showing the intersection of the lattice-like cores in the position sensor.

6(a) and 6(b) are enlarged plan views schematically showing light traveling paths in the intersection of the lattice-like cores.

Form for implementing the invention

Next, an embodiment of the present invention will be described in detail based on the drawings.

Fig. 1(a) is a plan view showing a first embodiment of a position sensor according to the present invention, and Fig. 1(b) is an enlarged cross-sectional view showing a central portion thereof. The position sensor of this embodiment is provided with a quadrangular sheet-shaped optical waveguide W, and the lattice-shaped core 2 is sandwiched by a rectangular plate-shaped lower cladding layer 1 and an upper cladding layer 3; A light-emitting element 4 to which one end of the linear core 2 of the core 2 is connected, and a light-receiving element 5 connected to the other end surface of the linear core 2 described above. Further, light emitted by the light-emitting element 4 passes through the core 2 and is received by the light-receiving element 5. In addition, in FIG. 1(a), the core 2 is indicated by a chain line, and the thickness of the chain line indicates the thickness of the core 2. In addition, in FIG. 1(a), the number of cores 2 is omitted. Also, the arrow of Fig. 1(a) indicates the direction in which the light advances.

Then, in the sheet-like optical waveguide W, the elastic modulus of the core 2 is set to be larger than the elastic modulus of the lower cladding layer 1 and the elastic modulus of the upper cladding layer 3. This is the first feature of the present invention. According to this feature, when the surface of the sheet-like optical waveguide W is pressed, the deformation ratio of the cross section of the core 2 in the pressing direction is smaller than the deformation ratio of the cross section of the upper cladding layer 3 and the lower cladding layer 1.

Further, in this embodiment, the surface of the lower cladding layer 1 opposite to the surface supporting the core 2 (the upper surface in Fig. 1(b)) is opposite to the surface (in Fig. 1(b) below). A portion corresponding to the center between the adjacent parallel core-shaped cores 2 and the cores 2 is provided with a linear protruding portion T in parallel with the linear core 2 described above. That is, the plurality of linear protruding portions T are formed in a lattice shape as shown in an enlarged plan view in Fig. 2, and the lattices are offset from each other without overlapping with the lattice of the core 2 in a plan view. another In addition, in Fig. 2, only the core 2 and the protruding portion T are shown, and in order to distinguish the core 2 from the protruding portion T, the core 2 is indicated by a solid line, and the protruding portion T is indicated by a broken line. The above-described protruding portion T is in a state in which the sheet-like optical waveguide W corresponding to the core 2 portion between the intersection portion and the intersection portion adjacent to the lattice-like core 2 (refer to FIG. 1(b) The rear portion of the 〕 is provided with a protruding portion T. In this state, it is a second feature of the present invention. According to this feature, a cavity portion H is formed between the adjacent protruding portion T and the protruding portion T (see FIG. 1(b)), and between the adjacent protruding portion T and the protruding portion T The portion of the sheet-like optical waveguide W is bent toward the cavity portion H by the protrusion portion T as a fulcrum by pressing (see FIG. 3(a)). Further, in this embodiment, as shown in FIG. 1(b), the sheet-shaped optical waveguide W is supported on the surface of the rigid plate 7 such as a resin plate or a metal plate via the protruding portion T.

In the above position sensor, the surface portion of the upper cladding layer 3 corresponding to the lattice-like core 2 is an input region, and input of characters or the like to the position sensor is directly or separated in the input region. A resin film, paper, or the like is formed by writing a character or the like on an input body such as a pen.

3(a) and 3(b), when the character or the like is input to the input body 10 such as a pen held by the hand 20 in the input region, the front end input portion 10a such as the pen tip is used. The pressing portion (see Fig. 3(a)) and the small finger of the hand 20 or the palm portion (small fish) of the hand 20 (see Fig. 3(b)) are elastic in the cross section in the pressing direction. The upper cladding layer 3 having a small rate is flattened and deformed, and the core 2 having a large modulus of elasticity has almost no change in cross-sectional shape (almost not flattened), and a portion along the front end input portion 10a or the hand 20 The lower cladding layer 1 having a small elastic modulus is sunk and bent.

Further, in the pressing portion of the front end input portion 10a, as shown in Fig. 3(a), since the front end input portion 10a is sharp, the bending state of the core 2 is violent, and light leaks (scatters) from the core 2 [ Refer to the arrow of the two-point chain line in Figure 3(a). Further, as described above, since the protruding portion T is provided on the back surface of the sheet-like optical waveguide W, the cavity portion H is formed between the adjacent protruding portion T and the protruding portion T. Therefore, in the pressing portion of the front end input portion 10a, when the portion between the adjacent protruding portion T and the protruding portion T of the sheet-shaped optical waveguide W is pressed by the front end input portion 10a such as a pen tip, The protruding portion T is bent as the fulcrum toward the hollow portion H. Thereby, even if the pressing of the front end input portion 10a such as the pen tip is only a little bit (even if the pressing is shallow), the bending of the sheet-shaped optical waveguide W of the pressing portion is more urgent, and the light is more easily removed from the core of the curved portion. Leakage (easy to scatter).

Therefore, in the core 2 pressed by the front end input unit 10a such as the pen tip, the light detection level of the light receiving element 5 (see FIG. 1) is greatly lowered. That is, the position (coordinate) of the front end input portion 10a such as the nib can be detected from the decrease in the light detection level. Further, as described above, even if the pressing of the front end input portion 10a such as the pen tip is only a little (even if the pressing is shallow), since the light detection level is greatly lowered, the detection sensitivity of the pressing (input) position (coordinate) is still Very good.

On the other hand, in the pressing portion of the hand 20 holding the input body 10, as shown in FIG. 3(b), the gap between the hand 20 and the adjacent protruding portion T and the protruding portion T is compared. It is much larger and more rounded than the front end input portion 10a (the radius of curvature is very large), so the bending of the core 2 is relatively gentle, and the above-mentioned light leakage (scattering) does not occur (light can be in the core 2) Do not leak out to the ground) (Refer to the arrow of the two-point chain line in Figure 3(b)].

Therefore, in the core 2 pressed by the hand 20 holding the input body 10, the light detecting level of the light receiving element 5 (see FIG. 1(a)) does not decrease. That is, the pressed portion of the hand 20 described above is not detected because the light detection level is the same as the unpressed state.

As described above, in the above-described position sensor, since the elastic modulus of the core 2 is set to be larger than the elastic modulus of the lower cladding layer 1 and the elastic modulus of the upper cladding layer 3 in the sheet-like optical waveguide W, When the input body 10 such as a pen held by the pen 10 inputs characters or the like in the input area of the sheet-like optical waveguide W, only the position of the front end input portion 10a such as the pen tip can be detected, and the portion of the hand 20 is not detected. Measured. Further, since the protruding portion T is provided on the back surface portion of the above-mentioned sheet-like optical waveguide W corresponding to the core portion 2 between the intersection portion and the intersection portion adjacent to the lattice-like core 2, the front end input such as the above-mentioned nib The detection sensitivity of the position of the portion 10a becomes high.

Here, the core 2, the lower cladding layer 1, the upper cladding layer 3, and the protruding portion T will be described in more detail.

The elastic modulus of the above core 2 is preferably in the range of 1 GPa to 10 GPa, and more preferably in the range of 2 GPa to 5 GPa. When the elastic modulus of the core 2 is too low, the cross-sectional area of the core 2 may not be maintained due to the pressure of the front end input portion 10a (the core 2 is crushed) due to the shape of the front end input portion 10a such as the nib. The position of the front end input portion 10a is appropriately detected. On the other hand, when the modulus of elasticity of the core 2 is too high, the bending of the core 2 due to the pressure of the front end input portion 10a may not be sharply curved along the front end input portion 10a, but may become a gentle curve. . Therefore, light does not occur Since the light detection level of the light receiving element 5 does not decrease from the leakage (scattering) of the core 2, there is a possibility that the position of the front end input portion 10a cannot be appropriately detected. Further, the size of the core 2 is set to, for example, a thickness of 10 to 100 μm, a width of 5 to 500 μm, and a pitch of 50 to 1500 μm.

The elastic modulus of the lower cladding layer 1 is preferably in the range of 0.1 MPa to 1 GPa, more preferably in the range of 1 MPa to 100 MPa. When the elastic modulus of the lower cladding layer 1 is too low, the lower cladding layer 1 may be too soft, and after being pressed by the front end input portion 10a such as a pen tip, the original state may not be returned to the original state, and the input may not be continuously performed. On the other hand, when the modulus of elasticity of the lower cladding layer 1 is too high, even if the pressure of the front end input portion 10a or the hand 20 is applied, the lower cladding layer 1 is not crushed and deformed, and the core 2 may be crushed. There is a possibility that the position of the front end input portion 10a cannot be properly detected. Further, the thickness of the lower cladding layer 1 is set, for example, in the range of 1 to 200 μm.

The elastic modulus of the upper cladding layer 3 is preferably in the range of 0.1 MPa or more and less than 10 GPa, more preferably in the range of 1 MPa or more and less than 5 GPa. When the elastic modulus of the upper cladding layer 3 is too low, it may be too soft. In some cases, the shape of the front end input portion 10a such as the nib may cause the upper cladding layer 3 to be damaged due to the pressure of the front end input portion 10a, and the core may not be protected. 2. On the other hand, when the modulus of elasticity of the upper cladding layer 3 is too high, even if the pressure of the front end input portion 10a or the hand 20 is applied, the upper cladding layer 3 is not crushed and deformed, and the core 2 may be pressed. In the case of flatness, there is a possibility that the position of the front end input portion 10a cannot be properly detected. Further, the thickness of the upper cladding layer 3 is set to be, for example, in the range of 20 to 2000 μm.

The forming material of the core 2, the lower cladding layer 1 and the upper cladding layer 3 For example, a photosensitive resin, a thermosetting resin, etc. can be mentioned, and the sheet-shaped optical waveguide W can be manufactured by the manufacturing method of this formation material. Further, the refractive index of the core 2 is set to be larger than the refractive indices of the lower cladding layer 1 and the upper cladding layer 3. Further, the adjustment of the elastic modulus and the refractive index can be adjusted, for example, by adjusting the type selection or the composition ratio of each of the forming materials. Further, a rubber sheet may be used as the lower cladding layer 1, and the core 2 may be formed in a lattice shape on the rubber sheet.

Although the above-mentioned protruding portion T is formed as long as the thickness is greater than 0 (zero), the detection sensitivity can be improved as described above, but from the viewpoint of more appropriately improving the detection sensitivity, the protrusion is set. The thickness of the portion T is preferably set to 10 μm or more, and more preferably 30 μm or more. Further, since the protruding portion T is too thick and the detection sensitivity is not so high, the thickness is preferably set to 200 μm or less, and more preferably 150 μm or less.

The width of the protruding portion T may be increased as described above as long as it is greater than 0 (zero) and is less than or equal to the length of the core portion between the adjacent intersection portion of the lattice core 2 and the intersection portion. Detection sensitivity. The width of the protruding portion T may vary depending on the width of the gap between the adjacent parallel linear core 2 and the core 2, but it is preferably set to, for example, 5 to 500 μm, and more preferably 30 to 300 μm. The range is better. The formation pitch of the protruding portion T is set to be the same as the formation pitch of the core 2.

Examples of the material for forming the protruding portion T include epoxy resin, PET (polyethylene terephthalate), PI (polyimide), and PEN (polyethylene 2,6 naphthalate). The resin is a rubber such as a silicone rubber or an acrylate rubber, or a metal such as stainless steel or aluminum, or paper. And by The above-described protruding portion T is formed in accordance with the method of forming the forming material. For example, the above-described protruding portion T can be formed by photolithography using a photosensitive resin for core formation as a forming material. Further, the elastic modulus of the protruding portion T is an elastic modulus which is crushed by pressing at the time of input, and the thickness is not 0 (zero), but it is elastic to some extent or more. The rate is good.

4 is an enlarged plan view (corresponding to the view of FIG. 2) showing the core 2 and the protruding portion T in the second embodiment of the position sensor of the present invention. The position sensor of this embodiment is in a state in which the protruding portion T is not formed in a lattice shape as in the first embodiment shown in FIG. 2, but is provided only in the sheet-shaped optical waveguide W (see FIG. 1(b). The portion corresponding to the core 2 portion between the intersection portion and the intersection portion adjacent to the lattice-like core 2 is regularly formed in a dot shape. The other portions are the same as in the first embodiment shown in Figs. 1(a) and 1(b), and the same portions are denoted by the same reference numerals. Further, the position sensor of this embodiment has the same action and effect as those of the first embodiment.

Further, in each of the above embodiments, one (one) protruding portion T is provided at the center between the adjacent intersecting portion and the intersecting portion of the lattice-like core 2, but the position and the strip of the protruding portion T are provided. The number (number) can also be other quantities. For example, the protruding portion T may be provided at a position deviating from the center between the adjacent intersection portion and the intersection portion of the lattice-like core 2, or a plurality of (multiple) protruding portions T may be provided, or the spacing may be formed. The protrusion T is set to be random.

Further, in each of the above embodiments, the rigid plate 7 is provided to support the sheet-shaped optical waveguide W, but the rigid plate 7 may not be provided. at this time, The sheet-shaped optical waveguide W of the position sensor can be input while being placed on a hard flat table such as a table via the protruding portion T.

Further, in each of the above-described embodiments, each of the intersecting portions of the lattice-shaped core 2 is generally formed in a state in which all four intersecting directions are continuous as shown in an enlarged plan view of FIG. 5(a), but may be in a continuous state. For other states. For example, as shown in FIG. 5(b), only one of the intersecting directions is separated by the gap G, and is in a discontinuous state. The gap G is formed by the following material for forming the cladding layer 1 or the upper cladding layer 3. The width d of the gap G is larger than 0 (zero) (as long as the gap G can be formed), and is usually set to 20 μm or less. As in the above case, as shown in Figs. 5(c) and (d), the two directions intersecting (Fig. 5(c) are two directions in the opposite direction, and Fig. 5(d) is two adjacent ones. The direction is a discontinuous state, and as shown in FIG. 5(e), the three intersecting directions are discontinuous, or as shown in FIG. 5(f), the four intersecting directions are all not Continuous state. In addition, a lattice shape having two or more intersecting portions among the intersecting portions as shown in FIGS. 5(a) to 5(f) may be provided. In other words, in the present invention, the "lattice shape" formed by the plurality of linear cores 2 means that a part of all the intersecting portions are formed as described above.

However, as shown in FIGS. 5(b) to 5(f), if at least one of the intersecting directions is discontinuous, the cross-loss of light can be reduced. That is, as shown in FIG. 6(a), in the intersection of all the four intersecting directions, pay attention to one direction of the intersection (the upward direction in FIG. 6(a)), and enter the A part of the light of the intersection reaches the wall surface 2a of the core 2 which is orthogonal to the core 2 from which the light can proceed. Since the angle of reflection on the wall 2a is large, light passes through the core 2 (refer to FIG. 6). (a) The arrow of the two-point chain line]. Such light This also occurs in the direction opposite to the above-mentioned opposite side (the downward direction in Fig. 6(a)). On the other hand, as shown in FIG. 6(b), when one of the intersecting directions (the upward direction in FIG. 6(b)) is discontinuous due to the gap G, the gap G and the core 2 are formed. In the interface of FIG. 6(a), a part of the light passing through the core 2 is not transmitted through the reflection angle at the interface, and is reflected at the interface, and continues to advance in the core 2 (refer to Figure 6 (b) of the two points of the chain line arrow]. Therefore, as described earlier, when at least one direction of the intersection is made discontinuous, the cross loss of light can be reduced. As a result, the detection sensitivity of the pressing position of the front end input portion 10a such as the pen tip can be further improved.

Further, in each of the above embodiments, the input body 10 may be pressed against the surface of the position sensor as described above, and may be not only a writing instrument that can be written on paper by ink or the like, but may not be written in ink or the like. A simple rod-shaped body for paper. When the pressing (the input of the front end input unit 10a or the input of writing is completed) is released, the lower cladding layer 1, the core 2, and the upper cladding layer 3 return to their original states due to their respective restoring forces. [Refer to Figure 1 (b)].

Next, an embodiment will be described together with a comparative example. However, the invention is not limited to the embodiments.

Example

[Forming material of lower cladding layer and upper cladding layer]

Component a: 60 parts by weight of an epoxy resin (manufactured by Mitsubishi Chemical Corporation, YL7410).

Component b: Epoxy resin (made by DAICEL, EHPE3150) 40 weight Share.

Component c: 4 parts by weight of a photoacid generator (manufactured by San-Apro Co., Ltd., CPI101A).

The material for forming the lower cladding layer and the upper cladding layer is prepared by mixing the components a to c.

[core forming material]

Component d: 90 parts by weight of an epoxy resin (EHPE 3150, manufactured by DAICEL Co., Ltd.).

Component e: 10 parts by weight of an epoxy resin (Epikote 1002, manufactured by Mitsubishi Chemical Corporation).

Component f: 1 part by weight of a photoacid generator (SP170, manufactured by ADEKA CORPORATION).

Component g: 50 parts by weight of ethyl lactate (manufactured by Wako Pure Chemical Industries, Ltd., solvent).

The core forming material is prepared by mixing the components d to g.

[Production of sheet optical waveguide]

First, a lower cladding layer is formed by a spin coating method using the above-described material for forming the lower cladding layer. The lower cladding layer had a thickness of 25 μm, an elastic modulus of 240 MPa, and a refractive index of 1.496. Further, the elastic modulus was measured using a viscoelasticity measuring device (RSA3, manufactured by TA Instruments Japan Inc.).

Then, on the surface of the lower cladding layer, a lattice-shaped core is formed by photolithography using the above-described core forming material. The core has a width of 100μm and a thickness of 50μm, adjacent to the parallel core and core The gap between the gaps was 500 μm, the modulus of elasticity was 1.58 GPa, and the refractive index was 1.516.

Next, the upper cladding layer is formed by spin coating using the material for forming the upper cladding layer on the surface of the lower cladding layer as described above. The thickness of the upper cladding layer (thickness from the core surface) was 40 μm, the modulus of elasticity was 240 MPa, and the refractive index was 1.496.

[Formation of the protruding part]

On the surface of the lower cladding layer opposite to the core forming surface, a lattice-like protruding portion is formed by photolithography using the same forming material as the core (see FIG. 1(b)). The linear projecting portion constituting the lattice-like projecting portion is formed in a portion corresponding to the center between the adjacent parallel linear core and the core, and is formed in parallel with the linear core. The protruding portion has a width of 100 μm and a thickness of 75 μm, and the width of the gap between the adjacent parallel linear protruding portions and the protruding portions is 500 μm.

[Production of position sensor]

The sheet-shaped optical waveguide is supported on one surface of a PET substrate (thickness: 1 mm) via the protruding portion. Then, a light-emitting element (XH85-S0603-2s, manufactured by Optowell Co., Ltd.) was connected to one end surface of the core, and a light-receiving element (manufactured by Hamamatsu Photonics Co., Ltd., s10226) was connected to the other end surface of the core to prepare an example. Position sensor.

[Comparative Example]

[Forming material of the upper cladding layer]

Component h: 40 parts by weight of epoxy resin (Epogosey PT, manufactured by Yokkaichi Synthetic Co., Ltd.).

Component i: 60 parts by weight of an epoxy resin (manufactured by DAICEL, 2021P).

Component j: 4 parts by weight of a photoacid generator (SP170, manufactured by ADEKA CORPORATION).

The material for forming the upper cladding layer is prepared by mixing the components h to j.

[core forming material]

Component k: 30 parts by weight of epoxy resin (Epogosey PT, manufactured by Yokkaichi Synthetic Co., Ltd.).

Component 1: 70 parts by weight of an epoxy resin (EXA-4816, manufactured by DIC Corporation).

Component m: 4 parts by weight of a photoacid generator (SP170, manufactured by ADEKA CORPORATION).

The core forming material is prepared by mixing the components k~m.

[Forming material of lower cladding layer]

Component n: Epoxy resin (manufactured by Yokkaichi Synthetic Co., Ltd., Epogosey PT) 40 parts by weight.

Component o: 60 parts by weight of an epoxy resin (manufactured by DAICEL, 2021P).

Component p: 4 parts by weight of a photoacid generator (SP170, manufactured by ADEKA CORPORATION).

The material for forming the lower cladding layer is prepared by mixing the components n to p.

[Production of sheet optical waveguide]

As in the above embodiment, a sheet-shaped optical waveguide of the same size was produced. However, the elastic modulus is 1 GPa for the upper cladding layer and 25 MPa for the core cladding layer. Then it is 1GPa. Further, the refractive index was 1.504 for the upper cladding layer, 1.532 for the core, and 1.504 for the lower cladding layer.

[Production of position sensor]

On one side of the PET substrate (thickness: 1 mm) as in the above-described embodiment, the one surface and the lower cladding layer were placed in contact with each other to support the sheet-shaped optical waveguide. Then, as in the above-described embodiment, the light-emitting element and the light-receiving element were connected, and a position sensor of a comparative example was produced.

[Evaluation of position sensor]

The paper was placed on the surface of the coating layer on each of the above position sensors, and a ballpoint pen having a diameter of 0.7 mm was hand-held to write characters on paper. As a result, the position sensor of the embodiment detects only the text written on the paper. In contrast, the position sensor of the comparative example detects not only the text written on the paper but also the portion of the hand holding the ballpoint pen.

Further, on the surface of the above-mentioned paper placed on the position sensor of the above-described embodiment, a load such as 0.25 N was applied to the tip of the ballpoint pen. As a result, the attenuation rate of the light detected by the above-mentioned light receiving element is as large as 80%.

From this result, it can be seen that the position sensor of the embodiment can detect only the text written on the paper without detecting unnecessary information. Moreover, it can be seen that even if the pressing of the pen tip is only a little bit, since the light attenuation rate is large, the sensitivity of the pen tip detection is still high.

Further, even if the protruding portion is regularly formed in a dot shape as shown in Fig. 4, the same tendency as in the above embodiment can be obtained.

In the above embodiments, the specific form of the present invention is shown. However, the above embodiments are merely illustrative and are not intended to limit the invention. Various modifications apparent to those skilled in the art are also within the scope of the invention.

Industrial use possibility

The position sensor of the present invention can be utilized in the case where, when a character or the like is input by holding an input body such as a pen, only the position or the movement trajectory of the front end input portion such as the desired nib can be detected with high sensitivity. It does not detect the position of unwanted hands, etc.

1‧‧‧Under cladding

2‧‧‧ core

3‧‧‧Upper coating

4‧‧‧Lighting elements

5‧‧‧Light-receiving components

7‧‧‧Rigid board

H‧‧‧The Cavity Department

T‧‧‧President

W‧‧‧Flake optical waveguide

Claims (2)

A position sensor is a sheet-shaped position sensor, comprising: a sheet-shaped optical waveguide having a plurality of linear cores formed in a lattice shape, a lower cladding layer supporting the cores, and Covering the upper cladding layer of the core; the light-emitting element is connected to one end surface of the core; the light-receiving element is connected to the other end surface of the core; and the protruding portion is disposed on the lower cladding layer and supports the core The sheet-shaped optical waveguide is bent with the protruding portion as a fulcrum, and the portion corresponding to the core portion between the intersection portion and the intersection portion of the lattice-shaped core is curved inside the surface on the opposite side, and The elastic modulus of the core is set to be larger than the elastic modulus of the lower cladding layer and the elastic modulus of the upper cladding layer, and the deformation ratio of the core cross section of the pressing direction in the pressed state of the sheet-shaped optical waveguide surface The deformation rate of the cross section of the upper cladding layer and the lower cladding layer is smaller than that of the upper cladding layer and the lower cladding layer, and the specific pressing portion is changed by the change in the amount of light propagation of the core due to the pressing of the surface of the position sensor. . The position sensor of claim 1, wherein the thickness of the protruding portion is set within a range of 10 to 200 μm.