TW201543274A - Position sensor - Google Patents

Abstract

Provided is a position sensor able to detect an input position normally (exactly as inputted) even if a surface is equipped with a protective film. This position sensor comprises: a sheet-shaped optical waveguide wherein a grid of cores are sandwiched between a sheet-shaped underclad layer and overclad layer; a light-emitting element connected to one end surface of linear cores that form the grid of cores; and a light-receiving element connected to the other end surface of the linear cores. A protective film (S) comprising a resin is positioned on the overclad layer, and the arithmetic average roughness Ra of the surface of the protective film in contact with the overclad layer is set to be greater than or equal to 10 [mu]m.

Description

Position sensor Field of invention

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

Background of the invention

A scheme of a position sensor that optically detects a pressing position (input position) has been proposed (see, for example, Patent Document 1). The plurality of core materials that are the optical path are disposed in the longitudinal and lateral directions, and the peripheral portion of each of the core materials covers the cladding layer to form a sheet shape, and the light from the light-emitting element is incident on one of the respective core materials. The end surface is further detected by the light-receiving element on the other end surface of each of the core materials. Further, when a part of the sheet-shaped position sensor surface is pressed with a finger or the like, the core material of the pressing portion (input position) can be flattened (the sectional area of the core material in the pressing direction is reduced), and the pressing is performed. In some of the core materials, the detection level of the light on the light-receiving element is lowered, so that the pressing position can be detected. When the above pressing is released, the above portion returns to the original flat state, and becomes a form for the next pressing.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. Hei 8-234895

Summary of invention

The inventors of the present invention have improved the durability of the sheet-like position sensor of Patent Document 1, and a sheet made of PET (polyethylene terephthalate) is used as a protective sheet without adhesion. The situation is downloaded to the surface of the position sensor. Then, characters or the like are input from the surface of the protective sheet by using a writing instrument such as a pen. However, there are cases where the input content cannot be detected accordingly.

Then, the inventors of the present invention discovered the cause, and found that when the input content cannot be detected correspondingly, the input trajectory (the pressing trajectory formed by the front end of the writing instrument) is not restored to the original flatness. The state is formed while still being in a state of being recessed into a groove. It was found that at this time, although the above protective sheet was not adhered to the surface of the position sensor, the recessed portion partially adhered to the surface of the position sensor. That is, as shown in the cross-sectional view of Fig. 5(a), the protective sheet S1 and the position sensor W1 are recessed together by the pressing of the writing instrument 10 at the time of the input, but the depression of the protective sheet S1 The portion of the position sensor W1 is also adhered to the surface of the position sensor W1. Further, as shown in the cross-sectional view of Fig. 5(b), since the protective sheet S1 itself has a certain degree of rigidity, the position sensor W1 is removed even if the pressing is released. The deformation is still constrained so that the above-mentioned depression cannot be restored to its original flat state. This recess keeps the surface of the position sensor W1 in a pressed state. Therefore, even if the front end of the writing instrument 10 is moved to another position, There is still a case where the depression of the movement trajectory (pressing trajectory) which does not need to be detected remains in the state (noise) which is to be detected, so that the input content is not detected correspondingly as described above. Further, in FIGS. 5(a) and 5(b), reference numeral 51 is a cladding layer, and reference numeral 52 is a core material.

The present invention has been made in view of such circumstances, and an object thereof is to provide a position sensor which can normally detect (corresponding to the input content) even if a protective sheet is provided on the surface. Enter the input location.

In order to achieve the above object, the position sensor of the present invention is a sheet-shaped position sensor including a sheet-shaped optical waveguide, a light-emitting element, and a light-receiving element, wherein the sheet-shaped optical waveguide has a plurality of lines formed in a lattice shape. a core material, a lower cladding layer for supporting the core materials, and an upper cladding layer covering the core material, the light emitting element being connected to one end surface of the core material, the light receiving element being connected to the above The other end face of the core material. In the following configuration, the protective sheet of the following (A) is placed on the surface of the upper cladding layer, and the light of the core material is pressed by any portion of the surface of the position sensor. The amount of change in the amount of the specific pressure is pressed.

(A) is a protective sheet in which the arithmetic mean roughness Ra of the contact surface with the upper cladding layer is set to 10 μm or more.

The inventors of the present invention have made it possible to detect the input position normally (correspondingly according to the input content) on the sheet-like position sensor even if the protective sheet is provided on the surface, firstly, the above-mentioned conventional In the technique, the input portion (pressing portion) in the protective sheet is attached to the table of the position sensor The reasons for this are discussed. As a result, it was found that the reason was that the surface roughness of the contact surface of the protective sheet in contact with the surface of the position sensor was small (arithmetic average roughness Ra was less than 10 μm). That is, it is known that the contact sheet of the protective sheet has a large contact area with the position sensor, and the adhesion is formed by the initial adhesion (tack) of the surface of the position sensor.

Therefore, the inventors of the present invention have made it possible to make the surface of the upper cladding layer of the sheet-like optical waveguide constituting the position sensor of the present invention have initial adhesion (tack), and the above protective sheet The input portion (pressing portion) still does not adhere to the surface of the upper cladding layer, and thus the surface roughness of the contact surface of the above protective sheet is repeatedly studied. As a result, when the arithmetic mean roughness Ra of the contact surface of the protective sheet with the upper cladding layer is set to 10 μm or more, the input portion (pressing portion) in the protective sheet does not adhere to the upper coating. The surface of the layer. Further, when the protective sheet is pressed while being input, the protective sheet is recessed together with the sheet-shaped optical waveguide, and when the pressing is released, the protective sheet is quickly restored to the original flat state together with the sheet-shaped optical waveguide. It has been found that the present invention can be achieved by detecting the input position normally (correspondingly according to the input content).

In the position sensor of the present invention, since the protective sheet having the arithmetic mean roughness Ra of the contact surface with the upper cladding layer is set to 10 μm or more is placed on the surface of the upper cladding layer of the sheet-shaped optical waveguide, It is achieved that the input portion (pressing portion) in the protective sheet does not adhere to the surface of the upper cladding layer. As a result, when the protective sheet is pressed while being input, the protective sheet can be recessed together with the sheet-shaped optical waveguide, and when the pressing is released, It is possible to quickly return the protective sheet to the original flat state together with the sheet-like optical waveguide. Therefore, the position sensor of the present invention can normally detect the input position (correspondingly according to the input content). Further, the position sensor of the present invention can be provided with a sensor excellent in durability by providing the above protective sheet.

S, S1‧‧‧protective film

W1‧‧‧ position sensor

W‧‧‧Flake optical waveguide

1‧‧‧Under cladding

2, 52‧‧‧ core material

2a‧‧‧ wall

3‧‧‧Upper coating

4‧‧‧Lighting elements

5‧‧‧Light-receiving components

51‧‧‧Cladding

7‧‧‧Rigid board

10‧‧‧Notes

10a‧‧‧ nib

G‧‧‧ gap

‧‧‧Width

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

Fig. 2 is a cross-sectional view schematically showing a state of use of the position sensor, wherein (a) is in a pressed state and (b) is in a state in which pressing is released.

3(a) to 3(f) are enlarged plan views schematically showing a cross-sectional form of a lattice-shaped core material in the position sensor.

4(a) and 4(b) are enlarged plan views schematically showing a traveling path of light in an intersection portion of the lattice-shaped core material.

Fig. 5 is a cross-sectional view schematically showing a state of use of a conventional position sensor, in which (a) is in a pressed state and (b) is in a state in which pressing is released.

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 an embodiment of a position sensor of the present invention, and Fig. 1(b) is an enlarged cross-sectional view showing a central portion thereof. The position sensor of this embodiment includes a quadrangular sheet-shaped optical waveguide W in which the lattice-shaped core material 2 is sandwiched by the quadrangular sheet-like lower cladding layer 1 and the upper cladding layer 3, The light-emitting element 4 connected to one end surface of the linear core material 2 constituting the lattice-shaped core material 2, and the light-receiving element 5 connected to the other end surface of the linear core material 2 are connected. Further, in the present embodiment, the optical waveguide W, the light-emitting element 4, and the light-receiving element 5 are provided on the surface of the rigid plate 7 such as a resin plate or a metal plate. Further, a protective sheet S made of a resin or the like is placed on the surface of the upper cladding layer 3. In the protective sheet S, the arithmetic mean roughness Ra of the contact surface (back surface) with the upper cladding layer 3 is set to 10 μm or more, and in the present embodiment, the arithmetic mean roughness Ra of the opposite surface (surface) is Set to be the same as the back. In addition, in FIG. 1(b), for the sake of easy understanding, the surface of the upper cladding layer 3 and the rough surface of the back surface are exaggerated and shown.

Further, light emitted from the light-emitting element 4 is formed to pass through the core member 2 and is received by the light-receiving element 5. Further, the surface portion of the upper cladding layer 3 corresponding to the lattice-shaped core material 2 is made an input region. In addition, in FIG. 1(a), the core material 2 is shown by a broken line, and the thickness of the core material 2 is shown by the thickness of a broken line. Further, in Fig. 1(a), the number of core materials 2 is omitted and shown. Further, the arrow of Fig. 1(a) indicates the traveling direction of light.

As described above, the main feature of the present invention is that in the position sensor including the sheet-like optical waveguide W, the surface portion of the sheet-like optical waveguide W corresponding to the portion of the lattice-shaped core member 2 (in the present embodiment) The protective sheet S is placed on the surface portion of the upper cladding layer 3, and the arithmetic mean roughness Ra of the contact surface of the protective sheet S and the upper cladding layer 3 is set to 10 μm or more. By providing such a protective sheet S, not only the durability of the position sensor can be improved, but also the input portion (pressing portion) in the protective sheet S can be prevented from adhering to the surface of the upper cladding layer 3, The position sensor can be made to detect the input position normally (according to the input content).

In other words, as shown in the cross-sectional view of Fig. 2 (a), when a character or the like is input from the surface of the protective sheet S by a writing instrument such as a pen, the writing pressure formed by the pen tip 10a or the like is transmitted to the upper surface through the protective sheet S. The cladding layer 3 is pressed against the sheet-shaped optical waveguide W. At this time, the protective sheet S is recessed together with the sheet-like optical waveguide W. As a result, the core material 2 is deformed at the pressing portion formed by the pen tip 10a or the like, and the propagation of light inside the core material 2 is hindered, and the detection level of light on the light receiving element 5 is lowered. Thus the pressed position can be detected. Further, the input of the above characters or the like may be performed on the paper placed on the surface of the protective sheet S.

Thereafter, as shown in the cross-sectional view of Fig. 2(b), when the above-described pressing is released, since the input portion (pressing portion) in the protective sheet S does not adhere to the surface of the upper cladding layer 3 as described above, Therefore, there is no deformation constraint formed by the protective sheet S, and the protective sheet S and the sheet-shaped optical waveguide W are quickly restored to the original flat state. In general, the protective sheet S has a restoring force, but even if it does not have a restoring force, the restoring force of the sheet-like optical waveguide W can be utilized to quickly return to the original flat state as described above. Thereby, the position sensor described above can quickly prepare for the next input (pressing).

When the protective sheet S is described in more detail, as described above, the protective sheet S is formed so as to have an arithmetic mean roughness Ra of a contact surface (back surface) with the upper cladding layer 3 of 10 μm or more. sheet. In particular, when the arithmetic mean roughness Ra is too large, the fear of damaging the surface of the upper cladding layer 3 tends to be high, and therefore, it is preferable to The arithmetic mean roughness Ra is set to 40 μm or less. The setting of the arithmetic mean roughness Ra may be performed by a polishing process, or a sheet having an arithmetic mean roughness Ra set in advance may be used as the protective sheet S.

The thickness of the protective sheet S is preferably set in the range of 15 to 200 μm from the viewpoint of accurately detecting the input. This is because when the thickness is too thin, the arithmetic mean roughness Ra tends to be set, and when the thickness is too thick, the sensitivity of the detection input (pressing) tends to decrease.

Examples of the material for forming the protective sheet S include PET (polyethylene terephthalate), PI (polyimide), and PEN (polyethylene naphthalate). A resin such as a polyester (polyethylene naphthalate), or a rubber such as a silicone rubber or an acrylic rubber, or a metal such as stainless steel or aluminum, or paper.

On the other hand, in the present embodiment, the sheet-like optical waveguide W is formed by embedding a core material 2 having a lattice shape on the surface portion of the sheet-shaped lower cladding layer 1 and the lower cladding layer 1 The top surface of the surface and the core material 2 are formed on the same plane, and a sheet-like upper cladding layer 3 is formed in a state of covering the surface of the lower cladding layer 1 and the top surface of the core material 2. In the sheet-like optical waveguide W of such a configuration, since the upper cladding layer 3 can be formed to have a uniform thickness, the pressing position in the input region can be easily detected. The thickness of each layer can be set, for example, in the range of 10 to 500 μm for the lower cladding layer 1 , 5 to 100 μm for the core material 2, and 1 to 200 μm for the upper cladding layer 3 .

Formation of the core material 2, the lower cladding layer 1 and the upper cladding layer 3 The material may, for example, be a photosensitive resin or a thermosetting resin, and a sheet-shaped optical waveguide W may be produced according to a method for forming a material. Further, the refractive index of the core material 2 is set to be larger than the refractive indices of the lower cladding layer 1 and the upper cladding layer 3. The adjustment of the refractive index can be performed, for example, by selecting or adjusting the composition ratio of each type of forming material. Further, a rubber sheet may be used as the lower cladding layer 1, and the core material 2 may be formed in a lattice shape on the rubber sheet.

Further, the elastic modulus of the core material 2 is preferably set to be larger than the elastic modulus of the lower cladding layer 1 and the upper cladding layer 3. The reason for this is that when the setting of the elastic modulus is reversed, the periphery of the core material 2 is hardened, and a sheet having an area larger than the area of the nib 10a or the like of the portion of the input region of the upper cladding layer 3 is pressed. When the portion of the optical waveguide W is recessed, there is a tendency that it is difficult to accurately detect the pressing position. Therefore, as the elastic modulus, for example, the elastic modulus of the core material 2 is set to be in the range of 1 to 10 GPa, and the elastic modulus of the upper cladding layer 3 is set to be in the range of 0.1 GPa or more and less than 10 GPa. The elastic modulus of the lower cladding layer 1 is set in the range of 0.1 to 1 GPa. At this time, even if the elastic modulus of the core material 2 is large, the core material 2 is hardly crushed under a general pressing force (the sectional area of the core material 2 hardly changes), but since it can be pressed by pressing The core material 2 is recessed to sink into the lower cladding layer 1 (refer to FIG. 2(a)), so light leakage (scattering) occurs from the bent portion of the core material 2 corresponding to the depressed portion, and the core is In the material 2, the detection position of the light receiving element 5 (see FIG. 1(a)) is lowered, and the pressing position can be detected.

Furthermore, in the above embodiment, the protection sheet S is calculated. The average roughness Ra is set to be the same whether it is the contact surface (back surface) or the opposite surface (surface) of the upper cladding layer 3, but the contact surface (back surface) with the upper cladding layer 3 is provided. The arithmetic mean roughness Ra is set to 10 μm or more, and the arithmetic mean roughness Ra of the opposite surface (surface) is independent of the arithmetic mean roughness Ra of the back surface, and may be any value.

Further, in the above-described embodiment, the intersecting portions of the lattice-shaped core member 2 are generally formed in a state in which they are continuous in all four directions of intersection as shown in an enlarged plan view in FIG. 3(a). But it can also be other forms. For example, as shown in FIG. 3(b), only one direction of the intersection is broken by the gap G, and it may be a discontinuous form. The gap G is formed by forming a material of the cladding layer 1 or the upper cladding layer 3 below. The width d of the gap G is set to exceed 0 (zero) (as long as the gap G is formed), and is usually 20 μm or less. Similarly, as shown in FIGS. 3(c) and 3(d), the two directions may be crossed (Fig. 3(c) is the two directions facing each other, and Fig. 3(d) is the adjacent two. The directions are formed in a discontinuous form. Alternatively, as shown in FIG. 3(e), the three intersecting directions may be formed in a discontinuous form. Alternatively, as shown in FIG. 3(f), all of the four intersecting directions may be formed in a discontinuous form. In addition, a lattice shape in which two or more types of intersection portions of the intersection portions shown in FIGS. 3(a) to (f) are provided may be employed. That is, in the present invention, the "lattice shape" formed by the plurality of linear core materials 2 means that a part or all of the intersection portions are formed as described above.

In particular, when at least one of the intersecting directions is discontinuous as shown in FIGS. 3(b) to (f), the light crossover loss can be reduced. That is, as shown in FIG. 4(a), all of the four intersecting directions are continuous intersections. When the attention is in one direction of the intersection [upward direction in FIG. 4(a)], a part of the light incident on the intersection portion reaches the core material 2 which is orthogonal to the core material 2 from which the light advances. The wall surface 2a has a large reflection angle on the wall surface, and thus penetrates the core material 2 (see the arrow of the two-dot chain line of Fig. 4(a)). The penetration of light like this also occurs in the direction opposite to the above (the downward direction in Fig. 4(a)). On the other hand, as shown in FIG. 4( b ), when one of the intersecting directions (the upper direction in FIG. 4( b )) is discontinuous due to the gap G, the gap G and the core material 2 are formed. The interface, and the portion of the light penetrating the core material 2 in FIG. 4(a) has a smaller angle of reflection on the interface, so that there is no penetration, and it is reflected at the interface, and is in the core. The material 2 continues to advance (refer to the arrow of the two-point chain line of Fig. 4(b)). From this, it can be seen that, as described earlier, when at least one of the intersecting directions is made discontinuous, it is possible to reduce the cross loss of light. As a result, the detection sensitivity of the pressing position of the pen tip 10a or the like can be improved.

Further, in the above-described embodiment, the rigid plate 7 is provided to support the sheet-shaped optical waveguide W or the like, 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 rigid flat table such as a table.

Further, in the above embodiment, an elastic layer such as a rubber layer may be provided on the back surface of the lower cladding layer 1. At this time, even if the restoring force of the lower cladding layer 1, the core material 2, and the upper cladding layer 3 is deteriorated, or the lower cladding layer 1 or the like is a layer made of a material having a poor restoring force, The elastic force of the elastic layer can be used to assist the above-described poor restoring force, and the original state can be restored after the pressing of the pen tip 10a or the like is released.

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

Example

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

Component a: 75 parts by weight of an epoxy resin (manufactured by Mitsubishi Chemical Corporation, YL7410).

Component b: 25 parts by weight of an epoxy resin (JER1007, manufactured by Mitsubishi Chemical Corporation).

Component c: 2 parts by weight of a photoacid generator (manufactured by SAN-APRO Co., Ltd., CPI101A).

The materials for forming the lower cladding layer and the upper cladding layer are prepared by mixing these components a to c.

[Forming material of core material]

Component d: 75 parts by weight of an epoxy resin (manufactured by DAICEL Co., Ltd., EHPE 3150).

Component e: Epoxy resin (manufactured by Tohto Kasei Co., Ltd., KI-3000-4) 25 parts by weight.

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

[Production of sheet-shaped optical waveguide]

On the surface of the glass substrate, the upper cladding layer was formed by a spin coating method using the material for forming the upper cladding layer. The upper cladding layer has a thickness of 25 μm. The modulus of elasticity is 3 MPa and the refractive index is 1.503. Further, a viscoelasticity measuring device (RSA3, manufactured by TA Instruments Japan Inc.) was used for the measurement of the elastic modulus.

Next, a core material is formed by photolithography using the material for forming the core material on the surface of the upper cladding layer. The core material had a thickness of 100 μm, and the core material of the lattice-like portion had a width of 100 μm, a pitch of 600 μm, a modulus of elasticity of 2 GPa, and a refractive index of 1.523.

Next, a lower cladding layer is formed by spin coating on the surface of the upper cladding layer by the material for forming the lower cladding layer so as to cover the core material. The thickness of the lower cladding layer (thickness from the surface of the upper cladding layer) was 500 μm, the modulus of elasticity was 3 MPa, and the refractive index was 1.503.

Then, an article having a double-sided tape (thickness: 25 μm) was adhered to one surface of a PET substrate (thickness: 1 mm). Next, the other adhesive surface of the double-sided tape is adhered to the surface of the lower cladding layer, and the upper cladding layer is peeled off from the glass substrate in this state.

[Example 1]

[Production of position sensor]

After that, a sheet made of PET (Z-Mate Film, manufactured by Sakae Co., Ltd., thickness: 50 μm, and arithmetic mean roughness Ra of the surface and the back surface of 35.1 μm) was used as a protective sheet as it is. The surface of the upper cladding layer. In addition, the arithmetic mean roughness Ra was measured by a laser microscope (OPTELICS H300, manufactured by LASERTEC Co., Ltd.).

Next, a light-emitting element (XH85-S0603-2s, manufactured by Optowell Co., Ltd.) was attached to one end surface of the core material, and the other end surface of the core material was attached. A light-receiving element (manufactured by Hamamatsu Photonics Co., Ltd., s10226) was attached to fabricate the position sensor of Example 1.

[Embodiment 2]

A PET sheet (EMBLET AT: thickness: 38 μm) was prepared, and one surface thereof was polished with an 800-gauge sandpaper to set the arithmetic mean roughness Ra to 12.4 μm. Then, the polished sheet is used as a protective sheet, and the polished surface is placed in contact with the surface of the upper cladding layer. The other portions are made the same as in the above-described first embodiment.

[Example 3]

A sheet made of PET (manufactured by Mitsubishi Chemical HD Co., Ltd., DIAFOIL S100: thickness: 50 μm) was prepared, and one surface thereof was polished with a sandpaper of No. 800, and the arithmetic mean roughness Ra was set to 10.5 μm. Then, the polished sheet is used as a protective sheet, and the polished surface is placed in contact with the surface of the upper cladding layer. The other portions are made the same as in the above-described first embodiment.

[Comparative Example 1]

In the position sensor of the above-described second embodiment, the sheet is not polished, and is placed as a protective sheet on the surface of the upper cladding layer. The arithmetic mean roughness Ra of the surface and the back surface of the sheet (protective sheet) was 5.9 μm. The other portions are made the same as in the above-described second embodiment.

[Comparative Example 2]

In the position sensor of the above-described third embodiment, the sheet is not polished, and is placed on the surface of the upper cladding layer as a protective sheet as it is. The arithmetic mean roughness Ra of the surface and the back surface of the sheet (protective sheet) was 3.1 μm. Other than this The portion is made the same as in the above-described embodiment 3.

[With or without adhesion]

After pressing the surface of the protective sheet with a ballpoint pen having a front end diameter of 0.5 mm, the pressing trace was visually observed. Then, when there is no interference fringe on the surface of the pressing trace, it is judged that there is no adhesion, and when there is interference fringe, it is judged that there is adhesion. The results are shown in Table 1 below.

[With or without noise]

On the surfaces of the protective sheets of the position sensors of the above-described Examples 1 to 3 and Comparative Examples 1 and 2, paper having a thickness of 90 μm was placed, and a character was written on the surface of the paper by a ballpoint pen having a front end diameter of 0.5 mm. Then, when the writing of the character ends (the pressing formed by the pen tip is released), the received spectrum is observed to confirm whether there is noise. The results are shown in Table 1 below.

As can be seen from the results of the above-mentioned Table 1, in the position sensors of the first to third embodiments, since the arithmetic mean roughness Ra of the contact surface of the protective sheet with the upper cladding layer is 10 μm or more, the pressing in the protective sheet is performed. There was no adhesion on the part, so there was no noise. On the other hand, in the position sensors of Comparative Examples 1 and 2, since the arithmetic mean roughness Ra is less than 10 μm, adhesion occurs in the pressed portion of the protective sheet, and noise is generated.

In addition, the sheet was replaced with a sheet made of PI, a sheet made of a silicone rubber, and a sheet made of stainless steel, and the results similar to those described above were obtained.

In the above-described embodiments, the specific embodiments of the present invention are shown, but the above-described embodiments are merely illustrative and not intended to be construed as limiting. Various modifications that are obvious to those of ordinary skill in the art to which the invention pertains are intended to be included within the scope of the invention.

Industrial availability

The position sensor of the present invention can be applied to input a character or the like with a writing instrument such as a pen, so that the input position can be normally detected (corresponding to the input content).

1‧‧‧Under cladding

2‧‧‧ core material

3‧‧‧Upper coating

4‧‧‧Lighting elements

5‧‧‧Light-receiving components

7‧‧‧Rigid board

S‧‧‧protection film

W‧‧‧Flake optical waveguide

Claims (1)

A sheet-shaped position sensor is a sheet-shaped position sensor having a sheet-like optical waveguide, a light-emitting element, and a light-receiving element, and the sheet-shaped optical waveguide has a plurality of linear core materials formed in a lattice shape, and is used for a lower cladding layer supporting the core material and an upper cladding layer covering the core material, wherein the light-emitting element is connected to one end surface of the core material, and the light-receiving element is connected to the other end surface of the core material, the sheet The position sensor of the shape is characterized in that a protective sheet of the following (A) is placed on the surface of the upper cladding layer and is pressed by any portion of the surface of the position sensor. The change in the amount of light propagation of the material is specific to the pressing portion, wherein (A) is a protective sheet in which the arithmetic mean roughness Ra of the contact surface with the upper cladding layer is set to 10 μm or more.