TW201610790A - Position sensor - Google Patents

Abstract

This invention provides a position sensor that makes it possible to save space and improve the sensitivity with which pressure positions are detected. Said position sensor contains a sheet-shaped optical waveguide, and said optical waveguide comprises a sheet-shaped core-pattern member sandwiched between a lower cladding layer and an upper cladding layer. The core-pattern member has a grid section and periphery sections. The grid section comprises a plurality of linear cores, and the periphery sections extend from the cores in the grid section and are laid out along the perimeter of the grid section. The section of the surface of the upper cladding layer corresponding to the grid section of the core-pattern member serves as an input region, and at least parts of edge sections of the optical waveguide, which correspond to the periphery sections of the core-pattern member, are folded over to the back of the optical waveguide. The indices of refraction of the upper cladding layer, the lower cladding layer, and the core are set such that the core has the highest index of refraction, followed by the lower cladding layer and then the upper cladding layer.

Description

Position sensor Field of invention

The present invention is directed to a position sensor that optically senses a push position.

Background of the invention

The applicant has proposed a position sensor that optically detects the pressing position so far (for example, refer to Patent Document 1). As shown in Fig. 8(a), this object has a quadrangular sheet-like optical waveguide W1 in which a sheet-like core pattern member is held by a quadrangular sheet-like lower cladding layer 11 and an upper cladding layer 13. The core pattern member has a lattice-like portion 12A in which the cores 12 for a plurality of linear light paths are arranged vertically and horizontally, and a periphery extending from the core 12 of the lattice-like portion 12A and along the outer periphery of the lattice-shaped portion 12A. The peripheral portion 12B of the state down configuration. Further, the elastic modulus of the core 12 is set to be larger than the elastic modulus of the under cladding layer 11 and the elastic modulus of the upper cladding layer 13. Further, one end surface of the core 12 of the outer peripheral portion 12B of the core pattern member is connected to the light-emitting element 14, and the other end surface of the core 12 is connected to the light-receiving element 15. The light emitted from the light-emitting element 14 is received by the light-receiving element 15 from the outer peripheral portion 12B of the light-emitting element 14 through the lattice-like portion 12A and the opposite-side outer peripheral portion 12B. Again, with the above core The lattice portion 12A of the core pattern member corresponds to the surface portion of the upper cladding layer 13 (the rectangular portion indicated by a dotted line in the center of Fig. 8(a)) as the input region 13A of the position sensor.

Further, as shown in FIG. 8(b), in the state where the position sensor is placed on the plane table 30 such as a table, for example, the pen tip 10 for input is pressed against the grid. The shaped portion 12A corresponds to the above-described input area 13A. Thereby, the cladding layer 13 and the under cladding layer 11 are deformed and collapsed in the cross section in the pressing direction, and the core 12 having a large elastic modulus hardly collapses (maintaining the cross-sectional area). Along the above pen tip 10, it is bent to sink toward the lower cladding layer 11. Further, the light propagating in the core 12 leaks toward the lower cladding layer 11 located outside the curved core 12 (refer to the arrow of the dotted line at the point of Fig. 8(b)). Therefore, in the core 12 of the pressing portion, the degree of light received by the light receiving element 15 is lowered, and the pressing position can be detected from the decrease in the degree of light receiving.

In general, in the optical waveguide, the refractive index of the core of the optical path is set such that the refractive index of the lower cladding layer and the upper cladding layer is higher, and the light propagating in the core is less likely to leak to the lower cladding layer and the upper cladding layer. . Moreover, the difficulty of leaking light from the core is equal to that of the lower cladding layer or the upper cladding layer, and the light transmission property of the optical waveguide is uniform, and the refractive index of the lower cladding layer and the upper cladding layer are made. It is technical common knowledge that the refractive index is the same.

Advanced technical literature Patent literature

[Patent Document 1] Japanese Patent No. 5513656

Summary of invention

In the above position sensor, the detection sensitivity for increasing the pressing position can be obtained.

Further, the position sensor has a peripheral portion (frame portion) of the optical waveguide W1 that is held by the side edge portion of the lower cladding layer 11 and the side edge portion of the upper cladding layer 13 of the outer peripheral portion 12B of the core pattern member. F1. That is, the position sensor requires a wider space than the input region 13A due to the presence of the peripheral portion F1 formed around the input region 13A. Further, when the input area 13A of the position sensor is widened or the detection accuracy of the pressing position of the input area 13A is increased, the number of the cores 12 must be increased, and therefore, the peripheral portion is also provided. It is necessary to widen the width of F1. Therefore, the above position sensor becomes a person who needs a wider space. There will be room for improvement at this point.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a position sensor capable of improving detection sensitivity and space saving of a pressing position.

In order to achieve the above object, the position sensor of the present invention is configured to have a sheet-like optical waveguide, the sheet core pattern member is held by the lower cladding layer and the upper cladding layer, and the sheet core core pattern member has a plurality of linear shapes. a lattice-shaped portion formed by the core, and an outer peripheral portion disposed in a state extending from the core of the lattice-shaped portion and along the outer periphery of the lattice-shaped portion; the light-emitting element is connected to one end surface of the core of the outer peripheral portion; And subject to The optical element is connected to the other end surface of the core of the outer peripheral portion; and at least a part of the peripheral portion of the optical waveguide corresponding to the outer peripheral portion of the core pattern member is such that the lower cladding layer is inside and the upper cladding layer is In the outer state, the back side of the optical waveguide is bent, and the position sensor has the following configuration (A) and (B), and the light emitted by the light-emitting element passes through the core of the optical waveguide. Receiving light by the light receiving element, and using the surface portion of the upper cladding layer corresponding to the lattice portion of the core pattern member as an input region, and specifying the input region by the amount of light propagation of the core that changes due to the pressing Pushing position.

(A) is a configuration in which the elastic modulus of the core is set to be larger than the elastic modulus of the under cladding layer and the elastic modulus of the over cladding layer, and the pressing direction is in a state of being pressed by the surface of the upper cladding layer. The deformation rate of the core section is smaller than the deformation ratio of the sections of the upper cladding layer and the lower cladding layer, and the core of the pressing portion is bent to sink toward the lower cladding layer.

(B) is a configuration in which a difference between a refractive index of the core and a refractive index of the upper cladding layer is set to be larger than a difference between a refractive index of the core and a refractive index of the under cladding layer, and in the pressing portion, The light propagating in the core is likely to leak to the under cladding layer, and the change in the amount of light propagation of the core caused by the pressing is increased, and in the above-mentioned bent portion, the light propagating in the core is less likely to leak to the upper portion. layers.

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

The inventors focused on improving the detection sensitivity of the pressing position. The leakage of light from the core of the push part is actively studied. That is, as described in the prior art, in the optical waveguide in which 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, the core of the pressing portion hardly collapses (maintaining the sectional area) State), bent into a downward cladding, and light propagating in the core leaks toward the lower cladding outside the curved core. Therefore, in the above research, the inventors thought that it is easy to leak light from the core of the pressing portion, and the change in the amount of light propagation at the core of the pressing is increased, whereby the detection sensitivity of the pressing position can be improved. Therefore, the difference between the refractive index of the core and the refractive indices of the lower cladding layer and the upper cladding layer (the refractive index of the lower cladding layer is the same as the refractive index of the upper cladding layer) becomes small.

However, in order to save space, when the under cladding layer is inside and the upper cladding layer is outside, when the back side of at least a part of the optical waveguide of the peripheral portion of the optical waveguide is bent, the secondary light is It becomes easy to leak from the core of the bent portion (curved surface portion) toward the outer cladding layer. Therefore, the amount of light propagation from the core is reduced, and it becomes difficult to receive light by the light receiving element.

On the contrary, when the difference in refractive index is made large, when the light is not easily leaked from the core of the bent portion, the secondary light is less likely to leak from the core of the pressing portion, and the detection sensitivity of the pressing position is lowered.

Therefore, the present inventors focused on the fact that the light in the core leaks toward the lower cladding layer outside the core bent by the pressing portion, and the cladding portion leaks toward the outer side in the bent portion, and is actively studied. Moreover, the technical knowledge of the prior art is broken, and the following method is found, and the present invention is completed: the difference between the refractive index of the core and the refractive index of the upper cladding layer is set to be larger than the difference between the refractive index of the core and the refractive index of the lower cladding layer. In this way, we can study the push part, the core The light among them easily leaks toward the lower cladding layer, and the change in the amount of light propagation at the core of the push increases, and in the bent portion, the light in the core is less likely to leak toward the upper cladding. In other words, due to the difference in refractive index, the detection sensitivity of the pressing position can be improved, and at least a part of the peripheral portion of the optical waveguide can be bent toward the back side of the optical waveguide, and space can be saved.

In the position sensor of the present invention, the core pattern is formed as a lattice-like portion and a peripheral portion disposed along the outer circumference, and a surface portion of the cladding corresponding to the lattice-shaped portion of the core pattern member is input. region. Further, in a state where the under cladding layer is inside and the over cladding layer is outside, at least a part of the peripheral portion of the optical waveguide corresponding to the outer peripheral portion of the core pattern member is bent toward the back side of the optical waveguide. Further, the elastic modulus of the core is set to be larger than the elastic modulus of the under cladding layer and the elastic modulus of the upper cladding layer. Moreover, the difference between the refractive index of the core and the refractive index of the upper cladding layer is set to be larger than the difference between the refractive index of the core and the refractive index of the lower cladding layer. Thereby, in the pressing portion, the light propagating in the core easily leaks toward the lower cladding layer, the change in the amount of light propagation at the core of the pressing increases, and in the above-mentioned bent portion, the light propagated in the core It is not easy to leak up the cladding. Therefore, the position sensor of the present invention can improve the detection sensitivity of the pressing position, and can save space in the portion of the peripheral portion of the above-mentioned bending.

In particular, when the front end 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 made thin.

1‧‧‧Under cladding

2‧‧‧ core

2A‧‧‧ latticed part

2B‧‧‧Outer part

3‧‧‧Upper cladding

3A‧‧‧Input area

4‧‧‧Lighting elements

5‧‧‧Light-receiving components

11‧‧‧Under the cladding

12‧‧‧ core

12A‧‧‧ latticed part

12B‧‧‧External part

13‧‧‧Upper cladding

13A‧‧‧Input area

14‧‧‧Lighting elements

15‧‧‧Light-receiving components

d‧‧‧The width of the gap

E‧‧‧Electronic circuit board

F, F1‧‧‧ Peripheral part

G‧‧‧ gap

R‧‧‧Flex radius

T‧‧‧ protruding width (frame width)

W, W1‧‧‧ optical waveguide

Fig. 1 is a plan view schematically showing an embodiment of a position sensor of the present invention.

Fig. 2 (a) is a plan view schematically showing a manufacturing process of the position sensor, (b) is an enlarged cross-sectional view of the central portion, and (c) is an enlarged cross-sectional view of the side edge portion.

Fig. 3 is an enlarged cross-sectional view schematically showing a state of the position sensor pressed by a pen tip.

Fig. 4 is an enlarged cross-sectional view showing a side edge portion schematically showing another embodiment of the position sensor of the present invention.

Fig. 5 is an enlarged cross-sectional view of an essential part schematically showing a modification of an optical waveguide constituting the position sensor.

[Fig. 6] (a) to (f) are enlarged plan views schematically showing the intersection form of the core of the lattice portion of the position sensor.

[Fig. 7] (a) and (b) are enlarged plan views schematically showing the path of light in the intersection portion of the core of the lattice-like portion.

8] (a) is a plan view schematically showing a conventional position sensor, and (b) is an enlarged cross-sectional view schematically showing a state of a conventional position sensor pressed by a pen tip.

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

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plan view showing an embodiment of a position sensor of the present invention. The position sensor of this embodiment is three places of the slightly square-shaped sheet-shaped optical waveguide W shown in the plan view of Fig. 2(a) (the left and right sides and the lower side in Fig. 2(a) Side] The peripheral portion F is bent toward the back side of the optical waveguide W. Thereby, the space saving of the above position sensor is sought. In Fig. 2(a), the three portions of the peripheral portion F indicated by the two-dot chain line are hidden in the back side of the optical waveguide W by the above-described bending, and are not visible in plan view.

That is, as shown in Fig. 2(a), the position sensor of this embodiment has a light-waveguide W having a substantially square shape and two light-emitting elements 4 disposed at two adjacent corners of the optical waveguide W. And two light receiving elements 5 disposed at the remaining two corners of the optical waveguide W. The rectangular portion at the center of the surface of the optical waveguide W (the quadrangular portion indicated by a dotted line in Fig. 2(a)) becomes the input region 3A, as shown in Fig. 2(b) (enlarged sectional view of the central portion of the position sensor) The electronic circuit board E is provided on the back surface portion of the optical waveguide W corresponding to the input region 3A. Further, as shown in Fig. 2(c) (enlarged sectional view of the side edge portion of the position sensor), among the four peripheral portions (frame portion) F of the optical waveguide W around the input region 3A, the above three places The peripheral portion F of the left and right sides and the lower side of Fig. 2(a) is bent. The end portion of the peripheral portion F of the bent portion is in contact with the electronic circuit forming surface of the electronic circuit board E (the surface of the optical waveguide W and the opposite side: the lower surface in FIG. 2(c)), and the light-emitting element 4 and The light receiving element 5 is mounted on the electronic circuit forming surface of the electronic circuit board E. On the other hand, in the embodiment, the peripheral portion F of the unfolded one (the upper side in Fig. 1 and Fig. 2(a)) is narrowly formed into a predetermined width without being bent.

More specifically, the optical waveguide W is formed on the surface of the cladding layer 1 in a slightly quadrangular sheet shape to form a sheet-like core pattern member, and the sheet-like core pattern member has a core 2 for a plurality of linear light paths. The latticed portion 2A is formed and extends from the core 2 of the lattice portion 2A. The outer peripheral portion 2B disposed along the outer circumference of the lattice-like portion 2A is further formed with the upper cladding layer 3 on the surface of the lower cladding layer 1 in a state in which the core pattern member is covered. Further, the surface portion of the cladding layer 3 corresponding to the lattice-like portion 2A of the core pattern member becomes the input region 3A. In addition, the portion of the outer peripheral portion 2B of the core pattern member that is held by the side edge portion of the under clad layer 1 and the side edge portion of the over clad layer 3 serves as a peripheral portion (frame portion) F of the optical waveguide W. In Fig. 1 and Fig. 2(a), the core 2 is shown by a broken line, and the thickness of the broken line shows the thickness of the core 2. Further, in Figs. 1 and 2(a), the number of cores 2 is roughly shown. Further, the arrows in Fig. 1 and Fig. 2(a) indicate the direction in which the light travels.

Further, in the optical waveguide W, the elastic modulus of the core 2 is set to be larger than the elastic modulus of the under clad layer 1 and the elastic modulus of the over clad layer 3. Preferably, the elastic modulus of each core, for example, the elastic modulus of the core 2 is set to be in the range of 1 GPa or more and 10 GPa or less, and the elastic modulus of the upper clad layer 3 is set to be in the range of 0.1 GPa or more and not more than 10 GPa, and the elastic modulus of the under clad layer 1 is set at 0.1 MPa or more and 1 GPa or less.

According to the magnitude relationship of the elastic modulus, when inputting, the input region 3A directly or through a resin film or paper, for example, when writing a character or the like with a pen for input, as described in the prior art, but as shown in the figure As shown in the cross-sectional view of Fig. 3, in the cross section in the direction in which the nib 10 is pushed, the elastic modulus is small, and the cladding layer 3 and the lower cladding layer 1 are deformed and collapsed, and the core 2 having a large elastic modulus hardly collapses (maintains). The state of the cross-sectional area), along the pen tip 10, is curved to sink toward the lower cladding layer 1. Further, the light propagating in the core 2 leaks toward the under cladding layer 1 located outside the curved core 2 (see the dotted line arrow of FIG. 3). Therefore, in the core 2 of the pressing portion, the degree of light received by the light receiving element 5 is lowered, and the pressing position can be detected by reducing the degree of light receiving.

Here, in this embodiment, the refractive index is set to be larger in the order of the cladding layer 3, the lower cladding layer 1, and the core 2. That is, the difference between the refractive index of the core 2 and the refractive index of the upper cladding layer 3 is set to be larger than the difference between the refractive index of the core 2 and the refractive index of the under cladding layer 1. For example, the refractive index of the core 2 is set in the range of 1.002 to 1.700, the refractive index of the upper cladding layer 3 is set in the range of 1.000 to 1.698, and the refractive index of the lower cladding layer 1 is set in the range of 1.001 to 1.699. . Further, the difference between the refractive index of the core 2 and the refractive index of the upper cladding layer 3 is preferably in the range of 0.005 or more and 0.6 or less.

Due to the difference in refractive index, the light propagating in the core 2 is likely to leak toward the under cladding layer 1 in the pressing portion, and the degree of light received by the light receiving element 5 is further lowered. Therefore, the reduction ratio becomes clearer. , the detection sensitivity of the pressing position can be improved.

Further, according to the difference in refractive index, light that has propagated through the core 2 in the bent portion (curved surface portion) of the optical waveguide W is less likely to leak toward the outer cladding layer 3 on the outer side. Therefore, the light from the light-emitting element 4 can be surely propagated toward the lattice-like portion 2A of the core pattern member, and the light propagating through the lattice-like portion 2A can surely reach the light-receiving element 5. Thereby, the pressing position can be appropriately and accurately detected.

Further, in this embodiment, one end surface of the core 2 of the outer peripheral portion 2B of the longitudinal core 2 in which the core pattern member lattice portion 2A is extended is connected to a light-emitting element 4, and at the other end face of the core 2 Connected to a light-receiving element 5, and further extended with the above-mentioned lattice-like portion One end face of the core 2 of the outer peripheral portion 2B of the lateral core 2 of 2A is connected to the other light-emitting element 4, and the other light-receiving element 5 is connected to the other end face of the core 2. The light emitted from the light-emitting element 4 is received by the light-receiving element 5 from the outer peripheral portion 2B of the light-emitting element 4 through the lattice-like portion 2A and the outer peripheral portion 2B on the opposite side.

As described above, the light-emitting element 4 and the light-receiving element 5 are respectively connected to the two directions (XY directions) in the longitudinal direction and the lateral direction of the lattice-like portion 2A, whereby the two directions are respectively controlled, and the pressing position of the input region 3A can be raised (XY coordinates). The detection accuracy. Further, as described above, since the light-emitting element 4 or the light-receiving element 5 is disposed at each corner portion of the slightly quadrangular sheet-shaped optical waveguide W, the light propagation distance from the light-emitting element 4 to the lattice-like portion 2A can be made. The light propagation distance from the lattice-like portion 2A to the light-receiving element 5 is shortened, so that the light propagation efficiency can be improved.

Further, as described above (see FIG. 2(c)), the electronic circuit board E is provided in a portion of the back surface (surface opposite to the core forming surface) of the cladding layer 1 below the optical waveguide W corresponding to the input region 3A. The front end portion of the peripheral portion F of the bent optical waveguide W is in contact with the electronic circuit forming surface of the electronic circuit board E (the surface opposite to the under cladding layer 1: the lower surface in FIG. 2(c)) The light-emitting element 4 and the light-receiving element 5 are mounted on an electronic circuit forming surface of the electronic circuit board E. Here, the thickness of the electronic circuit board E is set, for example, in the range of 1 to 10 mm, and the bending radius (inner diameter) R of the bent portion is set, for example, in the range of 0.5 to 5 mm. When the bending radius R is too small, the light propagation efficiency at the bent portion tends to decrease, and when it is too large, the above-mentioned bent portion protruding toward the input region 3A is protruded. The width (frame width) T becomes larger, and the space-saving effect of the position sensor tends to decrease.

The position sensor is manufactured by first fabricating the optical waveguide W and the electronic circuit substrate E individually. Next, on the surface on the opposite side of the electronic circuit forming surface of the electronic circuit board E, the back surface portion of the cladding layer 1 under the optical waveguide W corresponding to the input region 3A is brought into contact with each other. Next, the light-emitting element 4 and the light-receiving element 5 are connected to the end faces of the core 2 of the optical waveguide W. And the peripheral portion F of the optical waveguide W is bent perpendicularly to the core 2 of the peripheral portion F, and the front end portion of the bent peripheral portion F is formed to face the electronic circuit of the electronic circuit board E The light-emitting element 4 and the light-receiving element 5 are connected to the electronic circuit forming surface. In this way, the above position sensor can be obtained.

As a material for forming the under cladding layer 1, the core 2, and the over cladding layer 3, a photosensitive resin, a thermosetting resin, or the like can be exemplified, and the optical waveguide W can be produced by the method of forming the forming material. The adjustment of the above elastic modulus and refractive index can be performed, for example, by adjusting the selection or composition ratio of the type of each forming material. Further, the thickness of each layer is, for example, that the under cladding layer 1 is set in the range of 10 to 500 μm, the core 2 is in the range of 5 to 100 μm, and the upper cladding layer 3 is in the range of 1 to 200 μm. Further, as the under cladding layer 1, a rubber sheet can be used, and the core 2 is formed in a lattice shape on the rubber sheet.

Fig. 4 is a cross-sectional view showing an enlarged side portion of another embodiment of the position sensor of the present invention. In the above-described embodiment shown in Figs. 1 and 2 (a) to (c), the bent portion of the peripheral portion F of the optical waveguide W is bent by 90° toward the back side of the optical waveguide W. Corresponding to this, electronic The circuit board E is also used to bend 90 degrees. The other portions are the same as those of the above-described embodiment shown in Figs. 1 and 2 (a) to (c), and the same portions are denoted by the same reference numerals.

Also in this embodiment, similarly to the above-described embodiment shown in Figs. 1 and 2(a) to (c), the detection sensitivity of the pressing position can be improved, and the position sensor can be saved in a plan view. Spatialization. Further, the position sensor of this embodiment can be disposed inside the portion along the above-mentioned bent portion by 90° and at the corner of the table or the like.

Further, in each of the above embodiments, the cross-sectional structure of the optical waveguide W is as shown in Fig. 2(b), but other states may be employed. For example, as shown in the cross-sectional view of Fig. 5, FIG. 2(b) may be used. The structure is the upper and lower opposite. That is, the optical waveguide W is embedded in the surface portion of the sheet-like lower cladding layer 1, and the core 2 is buried. The surface of the under cladding layer 1 and the top surface of the core 2 are formed in the same plane, and the surface of the under cladding layer 1 is coated. In the state of the top surface of the core 2, a sheet-like upper cladding layer 3 is formed.

Further, in each of the above embodiments, three of the four peripheral portions F of the optical waveguide W are bent, and other states may be used. For example, all of the four portions may be bent, or two portions may be bent. You can only bend 1 place.

Further, in each of the above-described embodiments, the two light-emitting elements 4 and the light-receiving element 5 are used, but other states may be used. For example, one may be used, or three or more may be used. Further, in the above-described embodiment, the light-emitting element 4 or the light-receiving element 5 is disposed at each corner of the substantially square-shaped sheet-shaped optical waveguide W. However, in other states, for example, all of the light-emitting element 4 and the light-receiving element 5 may be disposed. The same one end edge of the quadrilateral sheet-shaped optical waveguide W.

Further, in each of the above-described embodiments, the respective intersecting portions of the core 2 of the lattice-like portion are formed in a state in which all of the four directions of the intersection are normally continuous as shown in the enlarged plan view of Fig. 6(a), but other states may be used. For example, as shown in FIG. 6(b), only the direction of the intersection 1 may be divided by the gap G to be discontinuous. The gap G described above is formed by forming a material of the lower cladding layer 1 or the upper cladding layer 3. The width d of the gap G exceeds 0 (zero) (as long as the gap G can be formed), and is usually set to 20 μm or less. Similarly, as shown in Figs. 6(c) and (d), the direction of the intersection 2 (Fig. 6(c) is the direction of 2, and Fig. 6(d) is 2 directions) may be Continuously, as shown in Fig. 6(e), the direction of the intersection 3 may be discontinuous, as shown in Fig. 6(f), and all of the four directions of the intersection may be discontinuous. Further, it may be a lattice shape including two or more types of intersection portions among the intersection portions shown in FIGS. 6( a ) to 6 ( f ). 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 intersection portions are formed as described above.

In the middle, as shown in Figs. 6(b) to (f), when at least one direction of the intersection is made discontinuous, the cross-loss loss of light can be reduced. That is, as shown in Fig. 7(a), all of the intersections in the direction of the intersection 4 are continuous intersections, and when focusing on the direction of the intersection 1 (upward in Fig. 7(a)), the light incident toward the intersection portion A part will reach the wall 2a of the core 2 orthogonal to the core 2 to which the light comes, and the incident angle on the wall will be smaller than the critical angle, so that it will pass through the core 2 (refer to Fig. 7(a) Two dotted arrows]. The light transmission is also generated in the direction opposite to the above (the lower side in Fig. 7(a)). On the other hand, as shown in FIG. 7(b), when the first direction of the intersection (the upper side in FIG. 7(b)) is discontinuous by the gap G, the boundary between the gap G and the core 2 is formed. In Fig. 7(a), part of the light transmitted through the core 2 is such that the incident angle at the interface is larger than the critical angle. Therefore, the interface is not transmitted through the interface, and is reflected at the interface, and proceeds to the core 2 (refer to the figure). 7(b) bis dotted arrow]. From this point of view, as described earlier, when at least one direction of the intersection is made discontinuous, the cross-loss loss of light can be reduced. As a result, the detection sensitivity of the pressing position of the pen tip or the like can be improved.

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

[Examples]

[Example 1]

[Forming material of the upper cladding layer]

Component a: 50 parts by weight of an epoxy resin (manufactured by Mitsubishi Chemical Corporation, YL7410).

Component b: 50 parts by weight of an epoxy resin (manufactured by DAICEL Co., Ltd., EHPE 3150).

Component c: 1 part by weight of a photoacid generator (manufactured by San-Apro Co., Ltd., CPI101A).

The material for forming the over cladding layer is prepared by mixing these components a to c.

[Core forming material]

Component d: 100 parts by weight of an epoxy resin (manufactured by DAICEL Co., Ltd., EHPE 3150).

Component e: 1 part by weight of a photoacid generator (SP170, manufactured by Adeka Co., Ltd.).

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

The core forming material is prepared by mixing these components d to f.

[Forming material of the lower cladding layer]

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

Component h: 40 parts by weight of an epoxy resin (manufactured by DAICEL Co., Ltd., EHPE 3150).

Component i: 1 part by weight of a photoacid generator (manufactured by San-Apro Co., Ltd., CPI101A).

The material for forming the under cladding layer is prepared by mixing these components g to i.

[Production of optical waveguide]

First, a lower cladding layer is formed by a spin coating method using the above-described under cladding layer forming material. The thickness of the lower cladding layer was 50 μm. The modulus of elasticity is 0.25 GPa and the refractive index is 1.496. For the measurement of the elastic modulus, a viscoelasticity measuring device (RSA3, manufactured by TA Instruments Japan Inc.) was used.

Next, on the surface of the under cladding layer, a sheet-like core pattern member having a lattice-shaped portion and a peripheral portion formed of a plurality of linear cores is formed by photolithography using the core forming material. The size of the lattice-shaped portion (input region) is 210 mm in length × 297 mm in width. Further, the core has a width of 100 μm and a thickness of 50 μm, and a gap width between the parallel linear cores adjacent to the lattice portion and the core is 500 μm. The modulus of elasticity is 1.5 GPa and the refractive index is 1.506.

Next, on the surface of the under cladding layer, the core cladding member is covered by the spin coating method using the above-mentioned over cladding layer forming material. The thickness of the upper cladding layer (thickness from the surface of the core) was 25 μm. The modulus of elasticity is 0.25 GPa and the refractive index is 1.486. In this way, a sheet-shaped optical waveguide is produced.

[Production of position sensor]

Preparing an electronic circuit substrate having an electronic circuit formed on one side and having the same size as the input region, and an electronic circuit with the electronic circuit substrate The surface on the opposite side of the surface is formed such that the back surface portion of the cladding below the optical waveguide corresponding to the input region abuts. Next, a light-emitting element (XH85-S0603-2s, manufactured by Optowell Co., Ltd.) was connected to one end surface of the core of the outer peripheral portion, and a light-receiving element was connected to the other end surface of the core of the outer peripheral portion (manufactured by Hamamatsu Photonics Co., Ltd., s10226) ). Further, the peripheral portion of the optical waveguide is bent to abut against the electronic circuit forming surface of the electronic circuit board, and the light-emitting element and the light-receiving element are mounted on the electronic circuit forming surface. The above-mentioned bending is that the protruding width of the bent portion protruding toward the periphery of the input region is 10 mm at two sides on both sides, and is 5 mm at one position therebetween, and the bending radius is 2 mm. At this time, the width of the three peripheral portions of the above-mentioned bending is 47.5 mm and 35.5 mm at two sides, and the middle portion thereof is 60.0 mm.

[Examples 2 to 4 and Comparative Examples 1 to 4]

In the first embodiment, the elastic modulus and the refractive index were changed by changing the kind or composition ratio of each of the forming materials of the optical waveguide, as shown in the following Table 1, and these were the examples 2 to 4 and the comparative examples 1 to 4.

[Detection sensitivity (attenuation rate) of the pressing position]

On the surface of the input region of each of the above position sensors, the tip of the ball pen (0.7 mm in diameter) was pressed with a load of 0.25 N. Further, when the light receiving level (light receiving intensity) of the light receiving element is not applied, the load is measured, and the application is performed, and the attenuation rate is calculated according to the following formula (1). The results are shown in Table 1 below. It is shown that the greater the above attenuation rate, the higher the detection sensitivity of the pressing position.

[Number 1]

[Bending loss]

Using the respective forming materials of the above Examples 1 to 4 and Comparative Examples 1 to 4, a linear optical waveguide was produced in the same manner as described above. Further, the center portion in the longitudinal direction of the linear optical waveguide is wound around the rod body having a radius of 2 mm, and in this state, light emitted from the light-emitting element is incident from one end of the optical waveguide. The light emitted from the other end is received by the light receiving element. The loss value (α) is calculated from the luminous intensity (A) of the light-emitting element and the received light intensity (B) of the light-receiving element according to the following formula (2). In the state in which the linear optical waveguide is linear, the received light intensity (C) is measured in the same manner as described above, and the loss value (β) is calculated according to the following formula (3). Then, the bending loss (D) is calculated according to the following formula (4). The results are shown in Table 1 below.

[Number 2] α = -10 log ₁₀ (B/A). . . (2)

[Number _{3] β = -10log 10 (C} / A). . . (3)

[Number 4] D = α - β . . . (4)

From the results of the above Table 1, it can be seen that the difference between the refractive index of the core and the refractive index of the upper cladding layer is set to be larger than the difference between the refractive index of the core and the refractive index of the lower cladding layer in Examples 1 to 4. The detection sensitivity of the pressing position becomes higher, and the bending loss becomes smaller. On the other hand, in Comparative Examples 1 to 4 which were not set to the difference in refractive index as described above, it was found that the detection sensitivity of the pressing position became low, or the bending loss became large or became The situation of both of them.

Further, in the above-described first to fourth embodiments, the optical waveguide has been shown in the cross-sectional view of Fig. 2(b). However, even if the optical waveguide is as shown in the cross-sectional view of Fig. 5, the display and the above embodiment can be obtained. 1~4 results of the same tendency.

In the above embodiments, the specific embodiments of the present invention have been shown, but the above embodiments are merely illustrative and not limiting. It will be apparent to those skilled in the art that various modifications are possible within the scope of the invention.

Industrial availability

The position sensor of the present invention can be utilized to improve the detection sensitivity and the space saving situation of the pressing position.

1‧‧‧Under cladding

2‧‧‧ core

2A‧‧‧ latticed part

2B‧‧‧Outer part

3‧‧‧Upper cladding

3A‧‧‧Input area

4‧‧‧Lighting elements

5‧‧‧Light-receiving components

E‧‧‧Electronic circuit board

F‧‧‧ Peripheral part

R‧‧‧Flex radius

T‧‧‧ protruding width (frame width)

W‧‧‧ optical waveguide

Claims (2)

A position sensor having a sheet-shaped optical waveguide for holding a sheet core member and a lower cladding layer, wherein the sheet core pattern member has a lattice shape composed of a plurality of linear cores a portion, and an outer peripheral portion extending from a core of the lattice portion and disposed along a periphery of the lattice portion; a light emitting element connected to one end surface of the core of the outer peripheral portion; and a light receiving element connected The other end surface of the core of the outer peripheral portion; further, at least a portion of the peripheral portion of the optical waveguide corresponding to the outer peripheral portion of the core pattern member in the position sensor is such that the lower cladding layer is inside and the above The state in which the upper cladding layer is outside is bent toward the back side of the optical waveguide, and the position sensor has the following configuration (A) and (B), and the light emitted by the light-emitting element passes through the light. The core of the waveguide receives light by the light-receiving element, and the surface portion of the upper cladding layer corresponding to the lattice-shaped portion of the core pattern member is regarded as an input region, and The core of the amount of a particular variation of the propagation of light input region of the pressing position. (A) is a configuration in which the elastic modulus of the above core is set to be higher than the above The elastic modulus of the lower cladding layer is greater than the elastic modulus of the upper cladding layer, and the deformation ratio of the core section of the pressing direction is higher than that of the upper cladding layer and the lower cladding layer under the pressing state of the surface of the upper cladding layer. The deformation rate is smaller, and the core of the above-mentioned pressing portion is bent to sink toward the above lower cladding. (B) is a configuration in which a difference between a refractive index of the core and a refractive index of the upper cladding layer is set to be larger than a difference between a refractive index of the core and a refractive index of the under cladding layer, and in the pressing portion, The light propagating in the core is likely to leak to the under cladding layer, and the change in the amount of light propagation of the core caused by the pressing is increased, and in the above-mentioned bent portion, the light propagating in the core is less likely to leak to the upper portion. layers. The position sensor of claim 1, wherein the front end of the bent portion is positioned on the back side of the optical waveguide corresponding to the input region.