KR20110123004A - Optical waveguide and optical panel - Google Patents

Abstract

PURPOSE: An optical waveguide and an optical touch panel are provided to be used in the outdoor where sun light touches. CONSTITUTION: A pigment mixture, which consists of more than 2 kinds of pigments, is contained in clad(14). The pigment mixture strongly absorbs the light of a visible ray area compared to a near infrared area. Disturbance light in the visible ray area in the clad is strongly absorbed. The light intensity of the disturbance light, which penetrates into a core through the clad, in the visible ray area is drastically reduced and an optical touch panel is used in the outdoor.

Description

Optical waveguide and optical touch panel {OPTICAL WAVEGUIDE AND OPTICAL PANEL}

The present invention relates to an optical waveguide and an optical touch panel using the same.

In the optical touch panel, it is important to remove extraneous light in order to obtain good characteristics. In a general optical touch panel, the light emitting element and the light receiving element are arranged to face each other around the coordinate input area. In that case, as a countermeasure against disturbance light, sealing resin (shielding member) which absorbs visible light is formed on a light receiving element (for example, patent document 1).

However, in the optical touch panel of this structure, the light receiving element is arranged in the vicinity of the coordinate input region where the disturbance light directly enters. Therefore, it is difficult to remove disturbance light only by the light shielding member.

On the other hand, the optical touch panel which provided the optical waveguide between the light emitting element and the coordinate input area, and between the coordinate input area and the light receiving element is known. In this optical touch panel, the optical signal from the light emitting element is emitted to the coordinate input area after passing through the optical waveguide. Moreover, the optical signal which passed the coordinate input area | region reaches a light receiving element after passing an optical waveguide (for example, patent document 2). The optical touch panel of this structure does not need to arrange light receiving elements around the coordinate input area. Therefore, it is stronger to disturbance light noise than a general optical touch panel.

Japanese Laid-Open Patent Publication No. 11-86698 Japanese Unexamined Patent Publication No. 2008-203431

However, even in an optical touch panel using an optical waveguide, it cannot be said that the disturbance of disturbance light is still sufficient. It is still difficult to use optical touch panels in very high-light environments, for example outdoors.

MEANS TO SOLVE THE PROBLEM This inventor earnestly examined about development of the optical touch panel which can be used also outdoors. As a result, the present invention has been completed by paying attention to the optical characteristics of the light emitting element and the light receiving element and the mechanism of generating noise due to disturbance light. In addition, in this specification, a "near infrared region" means the wavelength region of 700 nm or more and less than 2500 nm. In addition, a "visible region" means the wavelength range of 400 nm or more and less than 700 nm. In addition, an "ultraviolet region" means a wavelength region of 1 nm or more and less than 400 nm.

1 shows a typical light emission wavelength of a light emitting element and a typical light receiving wavelength region of the light receiving element. As shown in FIG. 1, the light emitting element generally used for an optical touch panel emits light of a near-infrared region (for example, 850 nm). On the other hand, a light receiving element generally used in an optical touch panel receives not only light in the near infrared region but also light in the visible region. As a result, the light receiving element receives not only the light of the near infrared region emitted from the light emitting element but also the disturbance light of the visible region that has penetrated the core through the clad. For this reason, noise due to disturbance light is generated.

Therefore, the present inventors contained the pigment mixture which consists of 2 or more types of pigment | dyes in a clad. This dye mixture absorbs light in the visible region more strongly than in the near infrared region. For this reason, the disturbance light of the visible region which has penetrated the clad is strongly absorbed, but the signal light of the near infrared region is hardly absorbed. Thereby, the disturbance light of the visible region which penetrates a clad and penetrates a core can be reduced significantly. Then, it was found that the optical touch panel can be used outdoors.

The gist of the present invention is as follows.

(1) The optical waveguide of the present invention is an optical waveguide having a clad and a core embedded in the clad. The light transmittance in the visible region of the clad is lower than the light transmittance in the near infrared region. This means that: When the transmittance spectra of the near infrared region and the visible region are compared, the transmittance of any wavelength in the visible region is lower than that of any wavelength in the near infrared region.

(2) In the optical waveguide of the present invention, the clad contains a pigment mixture composed of two or more pigments. The light transmittance of the visible region of the dye mixture is lower than the light transmittance of the near infrared region.

(3) In the optical waveguide of the present invention, the clad further contains an ultraviolet curable resin. The light transmittance of the ultraviolet region of the dye mixture is higher than the light transmittance of the visible region. This means that: When comparing the transmission spectra of the visible region and the ultraviolet region, for any wavelength of the visible region, there is a wavelength having a higher transmittance than that in the ultraviolet region.

(4) In the optical waveguide of the present invention, the light transmittance of the clad is 80% or more at a wavelength of 850 nm, less than 15% at a wavelength of 400 nm or more and less than 700 nm, and is 10% or more at a wavelength of 365 nm. .

(5) In the optical waveguide of the present invention, the thickness of the clad is 10 µm to 1500 µm.

(6) In the optical waveguide of the present invention, a portion covering the light exit end of the core of the clad or the light incident end of the light of the core of the clad forms a lens structure.

(7) The optical touch panel of the present invention includes the optical waveguide described above.

By this invention, the optical touch panel which can be used also in the outdoors which is exposed to direct sunlight can be implemented.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the area | region of the light emission wavelength of a light emitting element and the light reception wavelength of a light receiving element.
(A) is a perspective view of the optical waveguide of this invention, (b) is sectional drawing of the optical waveguide of this invention, (c) is sectional drawing of the optical waveguide of this invention.
(A) is a top view of the optical touch panel of this invention, (b) is sectional drawing of the optical touch panel of this invention.
4 is a graph of transmission spectra of the second clad of Examples and Comparative Examples.
5 is a graph of measurement of disturbance light noise in Examples and Comparative Examples.

[Optical waveguide]

The optical waveguide of the present invention has a clad and a core embedded in the clad. The optical waveguide of the present invention may have other components (for example, a substrate) as long as it has a clad and a core.

There is no restriction | limiting in particular in the form of the optical waveguide of this invention, For example, the form shown to FIG. 2 (a)-(c) is mentioned. 2 (a) is a perspective view of the optical waveguide 10 of the embodiment of the present invention. FIG. 2 (b) is a cross-sectional view taken along the line segment A-B of the optical waveguide of FIG. 2 (a). FIG. 2C is a cross-sectional view taken along the line segment C-D of the optical waveguide of FIG. 2A.

As shown to Fig.2 (a)-(c), in the optical waveguide 10 of this invention, the 1st clad 11, the several core 12, and the 2nd clad 13 are laminated | stacked in this order, have. The first clad 11 and the second clad 13 are collectively referred to simply as the clad 14. Since the cores 12 are separated from each other, the core 12 is embedded in the clad 14.

In FIG.2 (a)-(c), the lens structure 13a is formed in the cross section of the 2nd clad 13. As shown in FIG. This is to suppress the light emitted from the core 12 from diffusing in the longitudinal direction. Moreover, in order to focus the light incident on the core 12 in the longitudinal direction. In order to raise the utilization efficiency of signal light, it is preferable that such a lens structure 13a is provided. However, the lens structure 13a does not need to be formed.

The material of the first clad 11 and the material of the second clad 13 may be the same or different. However, in order to reduce manufacturing cost, it is preferable that it is the same material.

The use of the optical waveguide 10 of the present invention is not limited. Although the optical waveguide 10 of this invention can be used for an optical touch panel, an optical sensor, etc., it is especially used suitably for an optical touch panel.

[Clad]

The clad 14 used in the present invention contains a dye mixture composed of two or more kinds of dyes. The dye mixture strongly absorbs light in the visible region as compared with light in the near infrared region. Therefore, the disturbance light of the visible region which permeates the core 12 can be reduced. When this clad 14 is used for an optical touch panel having an optical waveguide, the influence of disturbance light can be very small. As a result, the optical touch panel can be used outdoors.

As the clad 14, there may be a constitution in which one kind of dye is contained in which the light transmittance in the visible region is lower than the light transmittance in the near infrared region. As an example of such a pigment | dye, black pigment | dyes, such as C. I. Solvent Black 27, 28, 2G, and the anthraquinone type pigment | dye of Unexamined-Japanese-Patent No. 9-3311 are mentioned.

However, as the clad 14 containing only one kind of such dye, it is difficult to realize a spectrum with high transmittance in the ultraviolet region shown in Fig. 4 (Example) described later. In the case where the ultraviolet ray is not in the spectrum having a high transmittance, it is difficult to contain the ultraviolet curable resin in the cladding 14 and the core 12, and thus the practicality is insufficient.

When the cladding 14 used in the present invention is used, it is not necessary to add a light shielding member anew, so that the optical touch panel can be miniaturized and thinned.

The clad 14 used in the present invention strongly absorbs light in the visible region, but hardly absorbs light in the near infrared region. Therefore, when light in the near infrared region emitted from the light emitting element propagates in the core 12, the light in the near infrared region is hardly attenuated by the influence of the clad 14 around the core 12.

For the same reason, light in the near-infrared region propagated in the core 12 shown in FIGS. 2A to 2C is emitted through the lens structure 13a formed in the clad 14 to the outside. In this case, the light in the near infrared region is hardly attenuated by the lens structure 13a. In addition, when light in the near infrared region enters the core 12 through the lens structure 13a formed in the clad 14, the light in the near infrared region is almost attenuated by the lens structure 13a. none.

It is preferable that a pigment mixture absorbs light of the wavelength range of 500 nm or more and less than 650 nm more strongly than the light of the wavelength range of 800 nm or more and less than 1000 nm. Moreover, it is further more preferable that a pigment mixture absorbs light of the wavelength range of 400 nm or more and less than 700 nm more strongly than the light of the wavelength range of 750 nm or more and less than 1500 nm.

It is preferable that the cladding 14 used in the present invention further contains an ultraviolet curable resin. Since ultraviolet curable resin is excellent in patterning property, the cladding with high patterning precision is obtained by containing an ultraviolet curable resin. In addition, the ultraviolet curable resin has a short curing time and generally has better release property than the thermosetting resin, so the productivity is good.

It is preferable that the pigment | dye mixture contained in the cladding 14 used for this invention has weak absorption of the light of an ultraviolet region compared with the light of a visible region. Then, even if it contains a pigment mixture, since the light of an ultraviolet region does not weaken, hardening of the ultraviolet curable resin contained in a clad is not prevented.

The dye mixture is not particularly limited as long as it absorbs light in the visible region more strongly than light in the near infrared region. As a pigment mixture, "FS-Black 1927" by Arimoto Chemical Industries, Ltd. is mentioned, for example.

It is preferable that content of the pigment mixture in the cladding 14 used for this invention is 0.01 weight%-5 weight%. When content of a pigment mixture is less than 0.01 weight%, there exists a possibility that the disturbance light of the visible region which permeate | transmits the clad 14 and may invade the core 12 may not be reduced enough. If the content of the dye mixture exceeds 5% by weight, for example, when light propagating in the core 12 is emitted to the outside through the lens structure 13a formed in the clad 14, the transmission of light is inhibited. There is concern.

The ultraviolet curable resin is not particularly limited as long as the ultraviolet curable resin can be cured. As ultraviolet curing resin, "EP4080E" by ADEKA company is mentioned, for example.

It is preferable that content of the ultraviolet curable resin in the cladding 14 used for this invention is 80.0 weight%-99.9 weight%. When content of ultraviolet curable resin is less than 80.0 weight%, there exists a possibility that patterning property may deteriorate. When content of ultraviolet curable resin exceeds 99.9 weight%, there exists a possibility that the light absorption of a visible region may become small.

It is preferable that the light transmittance of the cladding 14 used for this invention is 80% or more in wavelength 850 nm, It is more preferable that it is 85% or more, It is further more preferable that it is 90% or more. Moreover, it is preferable that it is less than 15%, and, as for the light transmittance of the cladding 14 used for this invention over the whole wavelength range of 400 nm or more and less than 700 nm, it is more preferable that it is less than 14.5%. In addition, the light transmittance of the cladding 14 used in the present invention is preferably 10% or more, more preferably 13% or more, and even more preferably 15% or more at a wavelength of 365 nm.

The light transmittance of the cladding 14 used in the present invention is 80% or more at a wavelength of 850 nm. Thereby, when the light of the near infrared region emitted from the light emitting element propagates in the core 12, it is possible to prevent the light of the near infrared region from being attenuated by the influence of the clad 14 around the core 12. . In addition, when the light propagated in the core 12 is emitted to the outside through the lens structure 13a formed in the clad 14, the light in the near infrared region can be prevented from being attenuated by the clad 14. have.

The light transmittance of the cladding 14 used in the present invention is less than 15% over the entire wavelength range of 400 nm or more and less than 700 nm. For this reason, the disturbance light of the visible region which permeates the core 12 can be reduced. Thereby, for example, even in roughness of 100,000 lux (direct sunlight level), it is possible to prevent the influence of disturbance light.

The transmittance of the cladding 14 used in the present invention is 10% or more at a wavelength of 365 nm. For this reason, the ultraviolet curable resin in the clad 14 can be cured practically without a problem.

It is preferable that the thickness of the cladding 14 used for this invention is 10 micrometers-1500 micrometers. If the thickness of the clad 14 is less than 10 µm, there is a fear that the disturbance light in the visible region may not be sufficiently absorbed. When the thickness of the clad 14 exceeds 1500 µm, a large amount of energy may be required to cure the ultraviolet curable resin in the clad 14.

The clad 14 used in the present invention can be produced by a method such as a dry etching method using a plasma, a transfer method, an exposure and development method, a photobleaching method, or the like.

The cladding 14 used in the present invention may have a single layer structure or a multilayer laminated structure. When the cladding 14 has a laminated structure, at least one layer thereof (for example, the second cladding 13) should just contain the dye mixture.

[core]

The core 12 used in the present invention is formed of a material having a high transmittance at a wavelength of light propagating and a refractive index higher than that of the clad 14. As for the material which forms the core 12, the ultraviolet curable resin excellent in patterning property is preferable. As ultraviolet curing resin, acrylic type ultraviolet curing resin, epoxy type ultraviolet curing resin, siloxane type ultraviolet curing resin, norbornene type ultraviolet curing resin, polyimide type ultraviolet curing resin, etc. are preferable.

There is no restriction | limiting in particular in the planar shape of the core 12 used for this invention, A linear form, a curved form, etc. are mentioned. Since the planar shape of the core 12 can guide light propagating efficiently to a coordinate input area | region, the L-shape shown in FIG.2 (a) is preferable.

There is no restriction | limiting in particular in the cross-sectional shape of the core 12 used for this invention. It is preferable that the cross-sectional shape of the core 12 is rectangular or trapezoid which is excellent in patterning property shown to FIG. 2 (b). As for the length (core 12 width) of the base of the core 12, 100 micrometers-500 micrometers are preferable. As for the height of the core 12, 10 micrometers-100 micrometers are preferable.

The core 12 used for this invention can be manufactured by methods, such as the dry etching method using plasma, the transfer method, the exposure and image development method, and the photobleaching method.

It is preferable that it is 0.01 or more, and, as for the maximum refractive index difference between the core 12 and the clad 14 in the wavelength of the light propagating in the core 12 used for this invention, it is more preferable that it is 0.02-0.3. The wavelength of the light propagating in the core 12 is the same as the wavelength of the light emitted from the light emitting element, and is, for example, 850 nm.

The refractive index of the resin forming the core 12 and the clad 14 used in the present invention can be increased or decreased depending on the type and content of the organic group introduced into the resin. For example, when the cyclic aromatic group (phenyl group or the like) is introduced into the resin molecule, the refractive index of the resin increases. In addition, when the content in the resin molecule of the cyclic aromatic group is increased, the refractive index of the resin increases. On the contrary, for example, when a linear or cyclic aliphatic group (methyl group, norbornene group, etc.) is introduced into the resin molecule, the refractive index of the resin becomes small. Moreover, when content in the resin molecule of a linear or cyclic aliphatic group is increased, the refractive index of resin will become small.

[Optical touch panel]

The optical touch panel of the present invention includes the optical waveguide of the present invention. Therefore, the optical touch panel of the present invention can be miniaturized and thinned, and can be used outdoors.

3A shows an example of a preferred embodiment of the optical touch panel 20 of the present invention. The optical touch panel 20 of the present invention includes a coordinate input region 21, a light emitting element 22 for emitting light in the near infrared region, and a light receiving element 23 for receiving light in the near infrared region and the visible region. It is provided. Further, a first optical waveguide 24 formed between the coordinate input region 21 and the light emitting element 22 is provided. Moreover, the 2nd optical waveguide 25 formed between the coordinate input area 21 and the light receiving element 23 is provided. The cross section of the side of the coordinate input region 21 of the first optical waveguide 24 faces the cross section of the side of the coordinate input region 21 of the second optical waveguide 25 with the coordinate input region 21 interposed therebetween. The optical waveguide of the present invention is used for at least the second optical waveguide 25 connected to the light receiving element 23.

In the optical touch panel 20, light propagating is guided to the light receiving element 23 by the optical waveguide 25. Thereby, the number of necessary light receiving elements 23 is significantly reduced compared with the optical touch panel which does not use an optical waveguide. In addition, since the degree of freedom of the arrangement of the light receiving element 23 is also high, the influence of the disturbance light is less than that of the optical touch panel which does not use the optical waveguide.

Moreover, in the optical touch panel 20 of this invention, the pigment mixture which strongly absorbs the light of a visible region was contained in the clad 25a of the 2nd optical waveguide 25 connected to the light receiving element 23 at least. . In this way, it is possible to prevent the disturbance light in the visible region from propagating in the core 25b and reaching the light receiving element 23. As a result, the optical touch panel 20 which can be used also in the outdoors with high illuminance was realizable.

There is no restriction | limiting in particular in the use of the optical touch panel 20 of this invention. The optical touch panel 20 of the present invention is, for example, a public input device such as an automatic ticket vending machine or a bank ATM, a portable device such as a mobile phone or a game machine, an office device such as a copy machine, a car navigation system, a POS system, or an industrial machine. Widely used in operation panels and the like.

[Coordinate input area]

In this specification, the "coordinate input area 21" means the area | region which inputs coordinates with a human finger, a pen tip, etc. in the optical touch panel 20. FIG. In the optical touch panel 20 of the present invention, the light receiving element 23 functions as a sensor. Therefore, the overlay film (layers, such as a film and glass) as a sensor, such as an ITO film | membrane, is not necessary in the coordinate input area 21.

FIG.3 (b) is typical sectional drawing of an example of preferable embodiment of the optical touch panel 20 of this invention. The light 26 emitted from the light emitting element 22 passes through the core 24b embedded in the clad 24a of the first optical waveguide 24, and passes through the air in the coordinate input region 21. Thereafter, the light 26 passes through the core 25b embedded in the clad 25a of the second optical waveguide 25 and reaches the light receiving element 23.

As shown to FIG. 3 (b), it is preferable that the coordinate input area 21 further includes the transparent panel 27 below. This is for protecting the liquid crystal display device or plasma display device formed below the coordinate input area 21. There is no restriction | limiting in particular in the transparent panel 27, A glass plate, an acryl plate, etc. are used. As for the thickness of the transparent panel 27, 10 micrometers-5 mm are preferable.

[Light emitting element, light receiving element]

The light emitting element 22 used in the present invention is an element that emits light in the near infrared region. As the light emitting element 22, a light emitting diode or a semiconductor laser is preferable, and VCSEL (vertical resonance plane light emitting laser) is more preferable. Since VCSEL can resonate light in the direction perpendicular to the substrate surface and emit light in the direction perpendicular to the surface, the VCSEL is excellent in light transmission. The wavelength of the light emitted from the light emitting element 22 is preferably in the near infrared region.

The light receiving element 23 used in the present invention is an element that receives light in the visible region and the near infrared region and converts an optical signal into an electrical signal. As the light receiving element 23, a phototransistor and a photodiode are preferable, and a CMOS image sensor and a CCD image sensor are more preferable.

Example

[Preparation of Forming Material of Clad 14]

(Component A) 100 parts by weight of an epoxy resin (EP4080E manufactured by ADEKA Corporation) capable of ultraviolet curing, containing an alicyclic skeleton

(Component B) 2 parts by weight of a photoacid generator (manufactured by San Apro Co., CPI-200K)

(Component C) 0.1 part by weight of a pigment mixture (Arimoto Chemical Industries, Ltd., FS-Black 1927) consisting of four pigments

The above components were mixed to prepare materials for forming the first clad 11 and the second clad 13.

[Preparation of Forming Material of Core 12]

(Component D) 40 parts by weight of an epoxy resin (Osaka EG, Ogso EG) capable of ultraviolet curing, containing a fluorene skeleton

(Component E) 30 parts by weight of an ultraviolet curable epoxy resin (manufactured by Nagase Chemtex, EX-1040) containing a fluorene skeleton

(Component F) 30 parts by weight of 1,3,3-tris (4- (2- (3-oxetanyl)) butoxyphenyl) butane

1 part by weight of component B

(Component G) 41 parts by weight of ethyl lactate

The said component was mixed and the formation material of the core 12 was prepared.

[Production of Optical Waveguide 10]

[Formation of First Clad 11]

The formation material of the clad was apply | coated to the surface of a polyethylene naphthalate (PEN) film (150 mm x 150 mm x 0.188 mm) with an applicator. Then, the ultraviolet irradiation exposure of 1,000 mJ / cm <2> was performed to the whole surface. Subsequently, heat processing was performed for 80 minutes and 5 minutes, and the 1st clad 11 was formed. It was 20 micrometers when the film thickness of the 1st clad 11 was measured with the contact thickness meter. In addition, the refractive index in the wavelength of 830 nm of the 1st clad 11 was 1.510.

[Formation of Core 12]

The formation material of the core 12 was apply | coated to the surface of the 1st clad 11 by the applicator. Next, 100 degreeC and the drying process for 5 minutes were performed. Next, a synthetic quartz photomask was printed on which a predetermined pattern was printed. Using an i-line band pass filter, 2500 mJ / cm <2> of ultraviolet irradiation exposure (peak wavelength 365nm) was performed by the proximity exposure method (gap 100 micrometer). Thereafter, heat treatment was performed at 100 ° C for 10 minutes.

Next, the unexposed part was melt | dissolved and removed by image development using the aqueous solution of (gamma) -butyrolactone. Thereafter, heat treatment was performed at 120 ° C. for 5 minutes to form the core 12.

When the cross-sectional dimension of the core 12 was measured with the microscope, it was 20 micrometers in width, and 50 micrometers in height. Moreover, the refractive index in wavelength 830 nm of the core 12 was 1.592.

[Formation of Second Clad 13]

The formation material of the 2nd clad 13 was apply | coated to the surface of the 1st clad 11 and the core 12 with the applicator. Next, the quartz mold having a negative shape of the lens structure was pressed and subjected to ultraviolet irradiation exposure (peak wavelength 365 nm) of 5000 mJ / cm 2 on the entire surface. Subsequently, heat processing was performed at 80 degreeC for 5 minutes. Thereafter, the mold was released to form a second clad 13 having the lens structure 13a shown in Figs. 2A to 2C. The film thickness of the second clad 13 was 1,000 µm.

The transmission spectrum of the 2nd clad 13 of the optical waveguide 10 of an Example is shown in FIG. 4 (Example). The light transmittance of the second clad 13 of the optical waveguide 10 of the example was 95% at a wavelength of 850 nm, less than 15% in the whole region of wavelengths 400 nm to 700 nm, and was 14% at a wavelength of 365 nm. . The refractive index in the wavelength of 830 nm of the 2nd clad 13 was 1.510. The transmission spectrum of the 2nd clad 13 substantially corresponded with the transmission spectrum of the pigment mixture (AFS, Black Industries, FS-Black 1927). With only one type of dye, it is difficult to obtain a peak near 380 nm of the spectrum of the example of FIG. 4. That is, with only one type of dye, it is difficult to lower the transmittance of the visible region and to increase the transmittance of the ultraviolet region. Therefore, in the Example, the pigment mixture which mixed 2 or more types of pigments was used.

The optical waveguide 10 after manufacture was cut | disconnected in the shape of a touch panel using a blade shape, and the cross section was cut | disconnected by the dicing apparatus.

[Manufacture of Optical Touch Panel 20]

The optical touch panel 20 was manufactured by combining the two optical waveguides 10 prepared in Example as shown in FIG. At the end of the first optical waveguide 24, a light emitting element 22 (VCSELL, manufactured by Optwell) that emits light having a wavelength of 850 nm was connected. The light receiving element 23 (TAOS Corporation make, CMOS linear sensor array) was connected to the terminal of the second optical waveguide 25. The output end of the optical waveguide 24 and the incidence end of the optical waveguide 25 are disposed to face each other with the coordinate input region 21 interposed therebetween, thereby manufacturing the optical touch panel 20 (3 inches diagonal) shown in FIG. It was.

[Comparative example]

[Preparation of Forming Material of Clad]

The material for forming the clad of the comparative example is the same as the material for forming the clad 14 of the example, except that the dye mixture does not contain a dye mixture. in short,

(Component A) 100 parts by weight of an epoxy resin (ADE40, EP4080E) capable of ultraviolet curing, containing an alicyclic skeleton

(Component B) 2 parts by weight of a photoacid generator (manufactured by San Apro Co., CPI-200K)

The above was mixed and the formation material of the 1st clad and the 2nd clad of the comparative example was prepared.

[Preparation of formation material of core]

The formation material of the core of a comparative example is the same as the formation material of the core 12 of an Example.

[Production of optical waveguide]

Except for the exposure conditions of the second clad, the optical waveguide of the comparative example was manufactured similarly to the Example. Since the pigment | dye mixture was not contained in the 2nd clad of the comparative example, the exposure amount of ultraviolet irradiation was reduced to 2,000 mJ / cm <2>. In addition, since the first clad has a thin film thickness, the effect of not containing the dye mixture is small. Therefore, exposure conditions were made similar to the Example.

The transmission spectrum of the 2nd clad of the comparative example is shown in FIG. 4 (comparative example). The light transmittance of the second clad of the comparative example was 92% at a wavelength of 850 nm, was 75% or more and less than 92% in the entire range of wavelengths 400 nm to 700 nm, and was 52% at a wavelength of 365 nm. Therefore, the second clad of the comparative example has high transparency not only in the near infrared region but also in the visible region.

[Production of an optical touch panel]

Two optical waveguides prepared in Comparative Example were combined as in FIG. 3 to prepare an optical touch panel of Comparative Example. The light emitting element and the light receiving element are the same as in the embodiment.

[Evaluation of disturbance light noise]

With respect to the optical touch panels of Examples and Comparative Examples, when light of 5,000 mW was emitted from the light emitting element in the dark room, all of the light receiving elements received light of 4.0 mW.

The optical touch panel of the Example and the comparative example was arrange | positioned in various measurement environments, and the intensity | strength of the disturbance light which the light receiving element received was measured. The measurement results are shown in Table 1 and FIG. 5.

Disturbance Light Noise Intensity (Saturation = 4.0 Hz) Measurement environment illuminance (lux) darkroom
One Fluorescent lamp
1,000 Indoor window
5,000 Outdoor shady
26,000 Direct sunlight
100,000 Example (iii) 0 0.1 0.2 0.3 0.4 Comparative example 0 0.5 2.7 3.7 3.7

In the optical touch panel 20 of the Example which contained the pigment mixture in the clad, in 100,000 lux illuminance (brightness of direct sunlight), the light receiving intensity was 0.4 kW, which was included in the usable noise intensity. On the other hand, in the optical touch panel of the comparative example which does not contain a pigment mixture in a clad, in the illuminance (brightness of outdoor shading) whose illuminance is 26,000 lux, the light reception intensity was already 3.7 kPa and it was not able to be used.

[How to measure]

[Refractive index]

The refractive index was measured using the prism coupler (SPA-4000 by SAIRON TECHNOLOGY).

[Core width, core height]

Core width | variety and core height cut | disconnected the optical waveguide using Dicer (DAD522 by DISCO), and measured and measured the cut surface using the microscope (VHX-200 by a Keyence company).

[Transmission spectrum]

The transmission spectrum was measured about the clad of 1,000 micrometers in thickness which formed on the glass substrate using the spectrophotometer (U-4100 by Hitachi Ltd. make). In addition, as a reference, the transmission spectrum of the glass substrate in which the clad was not formed was measured.

10: optical waveguide
11: first clad
12: core
12a: Exodus
13: the second clad
13a: lens structure
14: clad
20: optical touch panel
21: coordinate input area
22: light emitting element
23: light receiving element
24: optical waveguide
24a: clad
24b: core
25: optical waveguide
25a: clad
25b: core
26: light
27: transparent panel

Claims (8)

An optical waveguide having a clad and a core embedded in the clad,
An optical waveguide in which the light transmittance in the visible region of the clad is lower than the light transmittance in the near infrared region. The method of claim 1,
The said clad contains a pigment mixture consisting of two or more pigments,
An optical waveguide in which the light transmittance in the visible region of the dye mixture is lower than the light transmittance in the near infrared region. The method according to claim 1 or 2,
The clad further contains an ultraviolet curable resin,
An optical waveguide in which the light transmittance of the ultraviolet region of the dye mixture is higher than the light transmittance of the visible region. The method according to claim 1 or 2,
The light transmittance of the clad,
It is 80% or more in wavelength 850 nm,
It is less than 15% in the wavelength range 400 nm or more and less than 700 nm,
The optical waveguide which is 10% or more in wavelength 365nm. The method of claim 3, wherein
The light transmittance of the clad,
It is 80% or more in wavelength 850 nm,
It is less than 15% in the wavelength range 400 nm or more and less than 700 nm,
The optical waveguide which is 10% or more in wavelength 365nm. The method according to claim 1 or 2,
An optical waveguide, wherein the cladding has a thickness of 10 µm to 1500 µm. The method according to claim 1 or 2,
An optical waveguide in which the portion of the clad covering the light emitting end or the light incident end of the core forms a lens structure. The optical touch panel provided with the optical waveguide of Claim 1 or 2.

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