JP2012237833A - Light wave guide, and three dimensional optical touch panel having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light wave guide for detecting an XYZ coordinate despite its one layer configuration, and a three dimensional optical touch panel with a simple structure having the same.SOLUTION: A light wave guide 30 includes a 45° mirror arranged at a tip end 32a of a clad layer 32 and tilted to a principal plane of the light wave guide 30 by 45°±5°; an 8° mirror arranged between the 45° mirror and cores 31 and tilted to the principal plane of the light wave guide 30 by 8°±3°; and a plurality of cores 31 in which light incident points are aligned along a length direction of the 45° mirror.

Description

  The present invention relates to an optical waveguide used for an optical touch panel or the like.

  In this specification, directions of two adjacent sides of the screen of the optical touch panel are set as an X axis and a Y axis, and a vertical direction of the screen of the optical touch panel is set as a Z axis. Usually, the X axis, the Y axis, and the Z axis are orthogonal to each other.

  The conventional optical waveguide used on the light receiving side of the optical touch panel can detect the XY coordinates but cannot detect the Z coordinates.

  In an optical touch panel using a conventional optical waveguide, if an attempt is made to detect the Z coordinate, it is necessary to stack a plurality of optical waveguides (for example, Patent Document 1).

JP 2010-32378 A

  In an optical touch panel using a conventional optical waveguide, it is necessary to stack a plurality of optical waveguides in order to detect the Z coordinate. For this purpose, a plurality of optical waveguides are required, and there is a difficulty in laminating these optical waveguides with high accuracy.

  An object of the present invention is to realize an optical waveguide capable of detecting XYZ coordinates and a simple structure three-dimensional optical touch panel provided with the optical waveguide while being a single-layer optical waveguide.

  (1) The present invention is a planar optical waveguide provided with a core and a cladding layer in which the core is embedded. The optical waveguide according to the present invention includes a 45 ° mirror that is 45 ° ± 5 ° with the main surface of the optical waveguide, and a plurality of cores in which light incident points are aligned in the longitudinal direction of the 45 ° mirror. Is provided.

  (2) In the optical waveguide of the present invention, the vicinity of the light incident point of the core is a convex lens.

  (3) The present invention is a planar optical waveguide provided with a core and a cladding layer in which the core is embedded. The optical waveguide of the present invention is provided between the 45 ° mirror and the core of the cladding layer, and a 45 ° mirror that forms 45 ° ± 5 ° with the main surface of the optical waveguide, provided at the tip of the cladding layer. An 8 ° mirror that forms 8 ° ± 3 ° with the main surface of the optical waveguide, and a plurality of cores in which light incident points are aligned in the longitudinal direction of the 45 ° mirror.

  (4) In the optical waveguide of the present invention, the vicinity of the light incident point of the core is a convex lens.

  (5) The three-dimensional optical touch panel of the present invention includes a plurality of the optical waveguides according to (1) or (2) as light receiving side optical waveguides.

  (6) The three-dimensional optical touch panel of the present invention includes a plurality of the optical waveguides according to (3) or (4) as a light-receiving side optical waveguide.

  When the optical waveguide of the present invention is used on the light receiving side, the XYZ coordinates can be detected while being a single-layer optical waveguide. Moreover, since the three-dimensional optical touch panel of the present invention includes the optical waveguide of the present invention, the XYZ coordinates can be detected while the light receiving side optical waveguide has a simple structure of one layer.

(A) The top view of the optical waveguide of this invention, (b) The side view of the optical waveguide of this invention Plan view of the three-dimensional optical touch panel of the present invention (A) The top view of the optical waveguide of this invention, (b) The side view of the optical waveguide of this invention Plan view of the three-dimensional optical touch panel of the present invention (A) Change in signal intensity when the VCSEL light source is moved in the Y-axis direction, (b) Change in signal intensity when the multi-mode optical fiber light source is moved in the Y-axis direction (A) Change in signal intensity when the VCSEL light source is moved in the Y-axis direction, (b) Change in signal intensity when the VCSEL light source is moved in the Y-axis direction, and (c) Move the VCSEL light source in the Y-axis direction. Signal strength change (A) Signal intensity change when the multimode optical fiber light source is moved in the Y-axis direction, (b) Signal intensity change when the multimode optical fiber light source is moved in the Y-axis direction, (c) Y-axis direction Of signal intensity when moving multimode optical fiber light source

  The optical waveguide of the present invention includes a 45 ° mirror inclined at 45 ° ± 5 ° with respect to the main surface (YZ plane) at the light incident portion at the tip of the cladding layer, and has a plurality of light reflection points in the Z direction. And a plurality of cores corresponding to the respective light reflection points, and a plurality of optical sensor elements corresponding to the respective cores. The Z direction is the longitudinal direction of the 45 ° mirror.

  The optical waveguide of the present invention includes a 45 ° mirror inclined at 45 ° ± 5 ° with respect to the main surface (YZ plane) at the light incident portion at the tip of the cladding layer, and has a plurality of light reflection points in the Z direction. The clad layer between the light reflection point and the core is provided with an 8 ° mirror inclined at 8 ° ± 3 ° with respect to the main surface (YZ plane), and a plurality of cores corresponding to each light reflection point. And a plurality of optical sensor elements corresponding to each core.

  When the optical waveguide of the present invention is used on the light receiving side, it can detect the Z coordinate while having one layer in the Z direction.

  FIG. 1 is a first example of an optical waveguide 10 according to the present invention. 1A is a plan view of the optical waveguide 10 of the present invention, and FIG. 1B is a side view of the optical waveguide 10 of the present invention.

  The optical waveguide 10 of the present invention includes a core 11 and a clad layer 12 composed of an under clad layer and an over clad layer. The core 11 is embedded in the cladding layer 12. The exit end of the core 11 is optically coupled to the optical sensor 13.

  The light incident portion 12a at the tip of the clad layer 12 forms a 45 ° mirror that is inclined by 45 ° with respect to the main surface (YZ plane). The light 14 is incident on the light incident portion 12a parallel to the X axis, reflected by the 45 ° mirror of the light incident portion 12a, travels in the cladding layer 12 in the Y-axis direction, and enters the tip 11a of the core 11. . The tip 11a (light incident point) of the core 11 is aligned in the longitudinal direction of the 45 ° mirror.

  The tip 11a of the core 11 forms a fan-shaped plane convex lens. This planar convex lens has a function of converging the incident light 14 to the center of the core 11 on the YZ plane. This function increases the efficiency of guiding the incident light 14 to the core 11.

  The x marks (1) to (6) in FIG. The light 14 that has reached the reflection point (1) passes through the corresponding core 11 and enters the element 13a of (1) of the optical sensor 13.

  Similarly, the light 14 having reached the reflection point (2) is incident on the element 13a of (2) of the optical sensor 13. The light 14 that has reached the reflection point (3) is incident on the element 13a of (3) of the optical sensor 13. The light 14 that has reached the reflection point (4) is incident on the element 13a of (4) of the optical sensor 13. The light 14 that has reached the reflection point (5) is incident on the element 13a of (5) of the optical sensor 13. The light 14 that has reached the reflection point (6) is incident on the element 13a of (6) of the optical sensor 13.

  The reflection points (1) to (6) have the same XY coordinates and different Z coordinates. Therefore, according to the configuration of FIG. 1, the Z coordinate is detected in six stages at the same point in the XY coordinates. If necessary, the number of detection steps of the Z coordinate can be increased or decreased by changing the number of cores 11 and the number of elements 13a of the optical sensor 13.

  FIG. 2 shows a three-dimensional optical touch panel 20 provided with the optical waveguide 10 of the present invention. The three-dimensional optical touch panel 20 of the present invention includes three optical waveguides 10 of the present invention in series in the X-axis direction and three in series in the Y-axis direction. The optical waveguide 10 is used on the light receiving side of the three-dimensional optical touch panel 20.

  In the three-dimensional optical touch panel 20, 3 (Y-axis direction) × 6 (Z-axis direction) = 18 light beams in the X-axis direction are emitted from the light emitting side optical waveguide 21 on the right side, and the three light beams on the left side are emitted. The light enters the waveguide 10. Further, 3 (X-axis direction) × 6 (Z-axis direction) = 18 light beams in the Y-axis direction are emitted from the upper light-emitting side optical waveguide 22 and are incident on the lower three optical waveguides 10. .

  In the three-dimensional optical touch panel 20 shown in FIG. 2, the X coordinate is detected in three stages, the Y coordinate is detected in three stages, and the Z coordinate is detected in six stages. The three-dimensional optical touch panel 20 of the present invention can detect the Z coordinate in six stages while the light receiving side optical waveguide is a single layer.

  By increasing or decreasing the number of optical waveguides 10 coupled in series in the X-axis direction, the number of detection steps of the X coordinate can be increased or decreased. By increasing or decreasing the number of optical waveguides 10 coupled in series in the Y-axis direction, the number of detection steps of the Y coordinate can be increased or decreased.

  FIG. 3 shows a second example of the optical waveguide 30 of the present invention. 3A is a plan view of the optical waveguide 30 of the present invention, and FIG. 3B is a side view of the optical waveguide 30 of the present invention.

  The optical waveguide 30 of the present invention includes a core 31 and a clad layer 32 composed of an under clad layer and an over clad layer. The core 31 is embedded in the cladding layer 32. The exit end of the core 31 is optically coupled to the optical sensor 33.

  The light incident part 32a at the tip of the clad layer 32 forms a 45 ° mirror whose surface is inclined by 45 ° with respect to the main surface. A clad layer 32b (a portion not including the core 31) between the light incident portion 32a and the core 31 forms an 8 ° mirror whose surface is inclined by 8 ° with respect to the main surface.

  The light 34 enters the light incident portion 32a parallel to the X axis, is reflected by the 45 ° mirror of the light incident portion 32a, travels in the direction of the Y axis in the cladding layer 32, and is an 8 ° mirror of the cladding layer 32b. And is incident on the tip 31 a of the core 31.

  The tip 31a of the core 31 forms a fan-shaped plane convex lens. This planar convex lens has a function of converging the incident light 34 to the center of the core 31 on the YZ plane. This function increases the efficiency of guiding the incident light 34 to the core 31.

  The x marks (1) to (6) in FIG. The light 34 that has reached the reflection point (1) is reflected once again by the reflection point below it, passes through the corresponding core 31, and enters the element 33a of (1) of the optical sensor 33.

  Similarly, the light 34 that has reached the reflection point (2) enters the element 33a of (2) of the optical sensor 33. The light 34 that has reached the reflection point (3) is incident on the element 33a of (3) of the optical sensor 33. The light 34 that has reached the reflection point (4) is incident on the element 33a of (4) of the optical sensor 33. The light 34 that has reached the reflection point (5) is incident on the element 33a of (5) of the optical sensor 33. The light 34 that has reached the reflection point (6) is incident on the element 33a of (6) of the optical sensor 33.

  The reflection points (1) to (6) have the same XY coordinates and different Z coordinates. Therefore, according to the configuration of FIG. 3, the Z coordinate is detected in six stages at the same point in the XY coordinates. By changing the number of cores 31 and the number of elements 33a of the optical sensor 33 as necessary, the number of Z coordinate detection steps can be increased or decreased.

  The optical waveguide 30 in FIG. 3 is obtained by adding an 8 ° mirror to the optical waveguide 10 in FIG. 1. Since the optical waveguide 30 of FIG. 3 has an 8 ° mirror added, the incidence efficiency of the light 34 is higher than that of the optical waveguide 10 of FIG. The optical waveguide 10 of FIG. 1 has only a 45 ° mirror (no 8 ° mirror is provided). In the optical waveguide 10, a part of the incident light 14 tends to be diffused in the cladding layer 12 and not incident on the core 11 after being reflected by a 45 ° mirror. When an 8 ° mirror is added to the optical waveguide 10 of FIG. 1 and the optical waveguide 30 of FIG. 3 is used, the light 34 diffused in the cladding layer 32 can be reflected by the 8 ° mirror and incident on the core 31. As a result, the light incident efficiency of the optical waveguide 30 is higher than that of the optical waveguide 10.

  FIG. 4 shows a three-dimensional optical touch panel 40 provided with the optical waveguide 30 of the present invention. In the three-dimensional optical touch panel 40 of the present invention, three optical waveguides 30 of the present invention are provided in series in the X-axis direction, and three optical waveguides 30 of the present invention are provided in series in the Y-axis direction. The optical waveguide 30 is used on the light receiving side of the three-dimensional optical touch panel 40.

  In the three-dimensional optical touch panel 40, 3 (Y-axis direction) × 6 (Z-axis direction) = 18 light beams in the X-axis direction are emitted from the light emitting side optical waveguide 41 on the right side, and the three light beams on the left side are emitted. The light enters the waveguide 30. Further, 3 (X-axis direction) × 6 (Z-axis direction) = 18 light beams in the Y-axis direction are emitted from the upper light-emitting side optical waveguide 42 and are incident on the lower three optical waveguides 30. .

  In the three-dimensional optical touch panel 40 shown in FIG. 4, the X coordinate is detected in three stages, the Y coordinate is detected in three stages, and the Z coordinate is detected in six stages. The three-dimensional optical touch panel 40 of the present invention can detect the Z coordinate in six stages while the light receiving side optical waveguide is a single layer.

  By increasing or decreasing the number of optical waveguides 30 connected in series in the X-axis direction, the number of detection steps of the X coordinate can be increased or decreased. By increasing / decreasing the number of optical waveguides 30 coupled in series in the Y-axis direction, the number of Y coordinate detection steps can be increased / decreased.

[Material composition]
(Under clad layer material)
Component A: 100 parts by weight of an epoxy resin containing an alicyclic skeleton (EHPE3150 manufactured by Daicel Chemical Industries),
Component B: 2 parts by weight of a photoacid generator (CPI-200K manufactured by San Apro) was dissolved in cyclohexane to obtain a material for the underclad layer.

(Core layer material)
Component B: 1 part by weight of a photoacid generator (CPI-200K manufactured by San Apro),
Component C: 40 parts by weight of an epoxy resin containing a fluorene skeleton (Ogsol EG manufactured by Osaka Gas Chemical Company),
Component D: 30 parts by weight of an epoxy resin containing a fluorene skeleton (EX-1040 manufactured by Nagase ChemteX Corporation),
Component E: 30 parts by weight of 1,3,3-tris (4- (2- (3-oxetanyl)) butoxyphenyl) butane was dissolved in ethyl lactate to prepare a material for the core layer.

(Over clad layer material)
Component B: 2 parts by weight of a photoacid generator (CPI-200K manufactured by San Apro),
Component F: 50 parts by weight of an epoxy resin containing an alicyclic skeleton (EP4080E manufactured by Adeka),
Component G: 10 parts by weight of oxetane resin (OXT-221 manufactured by Toa Gosei Co., Ltd.)
Component H: 20 parts by weight of an epoxy resin (EP4085S manufactured by Adeka Company),
Component I: 20 parts by weight of a silicone resin (X-22-163 manufactured by Shin-Etsu Silicone Co., Ltd.) was mixed to prepare a material for the over clad layer.

[Optical waveguide fabrication]
(Undercladding layer fabrication)
On the surface of the substrate (float glass, 300 mm × 300 mm × 1.1 mm), the material of the under cladding layer was applied by a spin coater. Subsequently, a drying treatment at 100 ° C. for 5 minutes was performed.

Next, the entire surface was irradiated with ultraviolet rays of 2,000 mJ / cm ² . Subsequently, heat treatment was performed at 100 ° C. for 5 minutes. As described above, an undercladding layer was formed.

  The film thickness of the under cladding layer was 10 μm. The refractive index of the under cladding layer at a wavelength of 830 nm was 1.509.

(Core layer production)
The material of the core layer was applied to the surface of the under cladding layer by a spin coater. Subsequently, a drying treatment at 100 ° C. for 5 minutes was performed.

Next, a photomask was placed, and proximity exposure with ultraviolet rays was performed to transfer the pattern to the material of the core layer. The photomask is a synthetic quartz-based chromium mask and has a plurality of lens patterns. The proximity exposure gap was 50 μm. Ultraviolet rays passed through an i-line bandpass filter and had an intensity of 1,600 mJ / cm ² . Subsequently, heat treatment was performed at 100 ° C. for 10 minutes.

  Next, development was performed using a γ-butyllactone aqueous solution, and unexposed portions were dissolved and removed. Subsequently, heat treatment was performed at 120 ° C. for 5 minutes. The core layer was formed as described above.

  The width of the core layer (excluding the lens part and the joining part) was 15 μm. The height of the core layer was 50 μm. The refractive index of the core layer at a wavelength of 830 nm was 1.592.

(Over clad layer production)
An over clad layer material was applied so as to cover the entire surface of the core layer and the under clad layer, and a resin layer having a wet thickness of 60 μm was formed. Subsequently, heat treatment was performed at 80 ° C. for 5 minutes to remove bubbles in the resin layer around the core.

  Next, a concave mold (made of metal) having a negative type of mirror was filled with an overcladding layer material, and the resin layer was pressed and adhered to the surface of the overcladding layer material.

Next, an ultraviolet ray of 2,000 mJ / cm ² was irradiated from the substrate side. Subsequently, heat treatment was performed at 80 ° C. for 5 minutes.

  The concave mold was peeled off to obtain an overcladding layer having two types of mirrors with different angles. The thickness of the over clad layer was 300 μm. The over clad layer had a refractive index of 1.497 at a wavelength of 830 nm. As described above, a two-dimensional assembly of many optical waveguides was produced.

  Next, the two-dimensional aggregate of optical waveguides was cut into individual optical waveguides using a blade shape. Subsequently, the end face optically coupled to the light receiving element (CMOS sensor) was finished and cut by dicing.

  Next, a light receiving element (CMOS sensor) was optically coupled to the end face of the optical waveguide.

[Evaluation]
In the optical waveguide 30 shown in FIG. 3, light from a light source (VCSEL and multimode optical fiber) is reflected by a 45 ° mirror and an 8 ° mirror as designed and guided to the core 31, and is received by an optical sensor 33 (CMOS sensor). Confirmed that it was detected. It was also confirmed that the light receiving location of the CMOS sensor changed in conjunction with the position of the light source.

  FIG. 5 shows changes in the signal intensity of the optical sensor 33 when the light source is moved in the Y direction. FIG. 5A shows a case where the light source is a VCSEL, and FIG. 5B shows a case where the light source is a multimode optical fiber. There is almost no difference in the state of change in signal intensity between when the light source is a VCSEL and when it is a multimode optical fiber.

  FIG. 6 shows changes in the signal intensity of the optical sensor 33 when the light source is a VCSEL and the light source is moved in the Y direction. 6 (a) shows the incident light reflecting point when (6) in FIG. 3, FIG. 6 (b) shows the incident light reflecting point at (3), and FIG. 6 (c) shows the incident light. This is when the reflection point is (1) in FIG. That is, the Z coordinate is different in FIGS.

  Even if the Z coordinate of the light source is different, the change in the signal intensity of the optical sensor 33 is as expected. As the reflection point of incident light changes from (6) → (3) → (1), the signal intensity decreases as shown in FIGS. 6 (a) → (b) → (c). This is because the length of the core 31 increases as the reflection point of incident light changes from (6) → (3) → (1). This variation can be eliminated by adjusting the amplification degree of each element 33a of the optical sensor 33.

  FIG. 7 shows the same measurement as in FIG. 6 except that the light source is replaced with a multimode optical fiber. Although the decrease in the signal intensity that occurs according to FIGS. 7 (a) → (b) → (c) is less than that of FIG. 6, there is no difference from FIG.

[Measuring method]
[Refractive index]
The refractive indexes of the under-cladding layer, the core, and the over-cladding layer were measured using a prism coupler (SPA-4000 manufactured by SAIRON TECNOLOGY).

[Section observation]
The cross sections of the under clad layer, the core, and the over clad layer were measured using a microscope (VHX-200 manufactured by Keyence Corporation).

  The optical waveguide of the present invention is preferably used for a three-dimensional optical touch panel. The three-dimensional optical touch panel of the present invention is preferably used for a public touch panel used by a large number of unspecified people.

DESCRIPTION OF SYMBOLS 11 Core 11a Core tip 12 Clad layer 12a Light incident part 13 Optical sensor 13a Element 14 Light 20 Three-dimensional optical touch panel 21 Light emitting side optical waveguide 22 Light emitting side optical waveguide 30 Optical waveguide 31 Core 31a Core tip 32 Cladding layer 32a Light incident part 32b Cladding layer 33 Optical sensor 33a Optical sensor element 34 Light 40 Three-dimensional optical touch panel 41 Light emitting side optical waveguide 42 Light emitting side optical waveguide

Claims (6)

A planar optical waveguide comprising a core and a cladding layer embedded in the core,
A 45 ° mirror provided at the tip of the cladding layer and forming 45 ° ± 5 ° with the main surface of the optical waveguide;
An optical waveguide comprising a plurality of the cores in which light incident points are aligned in the longitudinal direction of the 45 ° mirror.   The optical waveguide according to claim 1, wherein the vicinity of the light incident point includes the core of a convex lens. A planar optical waveguide comprising a core and a cladding layer embedded in the core,
A 45 ° mirror provided at the tip of the cladding layer and forming 45 ° ± 5 ° with the main surface of the optical waveguide;
An 8 ° mirror, which is provided between the 45 ° mirror and the core of the cladding layer and forms 8 ° ± 3 ° with the main surface of the optical waveguide;
An optical waveguide comprising a plurality of the cores in which light incident points are aligned in the longitudinal direction of the 45 ° mirror.   The optical waveguide according to claim 3, wherein the vicinity of the light incident point includes the core of a convex lens.   A three-dimensional optical touch panel comprising the plurality of optical waveguides according to claim 1 as light receiving side optical waveguides.   A three-dimensional optical touch panel comprising the plurality of optical waveguides according to claim 3 as light receiving side optical waveguides.

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