TW201928432A - Optical waveguide - Google Patents

Abstract

An optical waveguide includes cladding and a core embedded in the cladding. The core comprises: a first incidence surface that is arranged at the end face upstream in the light transmission direction and allows light with a first wavelength to enter the core; a second incidence surface that is arranged at the end face upstream in the transmission direction separate from the first incidence surface by a gap in a direction intersecting with the transmission direction and allows light with a second wavelength shorter than the first wavelength to enter the core; a third incidence surface that is arranged at the end face upstream in the transmission direction separate from the first incidence surface and the second incidence surface by a gap in a direction intersecting with the transmission direction and allows light with a third wavelength shorter than the second wavelength to enter the core; a joint that is arranged downstream of the first incidence surface, the second incidence surface, and the third incidence surface in the transmission direction and where the light with the first wavelength, the light with the second wavelength, and the light with the third wavelength join together; and an emission surface that is arranged downstream from the joint in the transmission direction and wherefrom the light with the first wavelength, the light with the second wavelength, and the light with the third wavelength are emitted. A first area S1 of the first incidence surface, a second area S2 of the second incidence surface, a third area S3 of the third incidence surface are substantially identical. A first attenuation ratio R1 for the light with the first wavelength which is incident on the first incidence surface and emitted from the emission surface is greater than a second attenuation ratio R2 for the light with the second wavelength which is incident on the second incidence surface and emitted from the emission surface. The second attenuation ratio R2 is greater than a third attenuation ratio R3 for the light with the third wavelength which is incident on the third incidence surface and emitted from the emission surface.

Description

Optical waveguide

FIELD OF THE INVENTION The present invention relates to an optical waveguide.

BACKGROUND OF THE INVENTION Conventionally, an optical waveguide is known in which a plurality of optical paths are converged into one at a junction. In this optical waveguide, for each of a plurality of incident surfaces, each of a plurality of kinds of light having different wavelengths is incident, and they are made to converge at a confluence part, and then they are arranged on the downstream side of the confluence part. Shot from the exit surface.

For example, a multi-mode optical waveguide having different core materials having different widths has been proposed (see, for example, Patent Document 1). In the multimode optical waveguide of Patent Document 1, the propagation constants of the plurality of optical paths are different by making the widths of the plurality of branched core materials different, and a large amount of light is propagated to the branched core material having a large propagation constant. .
Prior art literature patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2007-225920

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, when a light having a relatively short wavelength and a light having a relatively long wavelength among a plurality of lights having different wavelengths are incident on two incident surfaces having the same structure, the wavelength is longer than the wavelength. The proportion of light with a shorter wavelength in the light path is larger. Therefore, among the light emitted from the emission surface, the intensity of the light having a shorter wavelength is more greatly reduced than that of the light having a longer wavelength. As a result, there is a problem that the intensity of the two lights after the confluence becomes uneven.

On the other hand, although Patent Document 1 differentiates the widths of the divergent core materials and selectively discriminates light, as long as the patent document 1 changes the width for each of the plural divergent core materials and shortens the wavelength Light is incident on the incident surface of the branched core material with a wide width, and light with a longer wavelength is incident on the incident surface of the branched core material with a narrow width. It is possible to solve the above-mentioned problems by suppressing the decrease in the intensity of light having a shorter wavelength.

However, if a plurality of lights are incident on the incident surfaces having different widths, it is easy to form a position shift. Specifically, each of the plurality of light emitting devices and each of the plurality of incident surfaces must be aligned in accordance with the width of the plurality of incident surfaces. When the alignment with the higher accuracy cannot be performed, When it is in the position, there is a problem that the optical connection between the two cannot be performed accurately.

The present invention provides a light beam of a first wavelength, a light of a second wavelength, and a light of a third wavelength that can be easily and accurately incident on each of the three incident surfaces, and furthermore, three kinds of light can be incident. An optical waveguide that merges and exits with a uniform intensity.
Means to solve the problem

The present invention (1) includes an optical waveguide including a covering material and a core material buried in the covering material, the core material having:
The first incident surface is disposed on an upstream end surface in a light transmission direction, and allows light of a first wavelength to be incident on the core material;
The second incident surface is disposed on the upstream end surface of the transmission direction at a distance from the first incident surface in a direction crossing the transmission direction, and supplies light of a second wavelength shorter than the first wavelength. Incident on the aforementioned core material;
The third incidence surface is disposed on the upstream end surface of the transmission direction at a distance from the first incidence surface and the second incidence surface in a direction crossing the transmission direction, and is shorter than the second wavelength. Light of a third wavelength is incident on the core material;
The confluence part is disposed downstream of the first incident surface, the second incident surface, and the third incident surface on the downstream side in the transmission direction, and supplies the light of the first wavelength, the light of the second wavelength, and the third Wavelengths of light converge; and an exit surface disposed on the downstream side in the transmission direction of the confluence unit and emitting the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength,
The first area S1 of the first incident surface, the second area S2 of the second incident surface, and the third area S3 of the third incident surface are substantially the same,
The first attenuation ratio R1 of the light of the first wavelength that is incident on the first incident surface and is emitted from the exit surface is greater than the light of the second wavelength that is incident on the second incident surface and is emitted from the exit surface. The second attenuation ratio R2 is larger, and the second attenuation ratio R2 is larger than the third attenuation ratio R3 of the light of the third wavelength incident on the third incident surface and emitted from the exit surface.

In this optical waveguide, each of the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength is incident on the first incident surface, the second incident surface, and the third incident surface. The confluence part merges three kinds of light, and the three kinds of light are emitted from the exit surface.

In addition, since the first area S1 of the first incidence surface, the second area S2 of the second incidence surface, and the third area S3 of the third incidence surface are substantially the same, the light emitting device and the three incidence surfaces can be easily formed. Alignment, and can optically connect the two easily and accurately.

In addition, the first attenuation ratio R1 of the light of the first wavelength is larger than the second attenuation ratio R2 of the light of the second wavelength shorter than the first wavelength, and the second attenuation ratio R2 is larger than the first attenuation ratio R2. Since the third attenuation ratio R3 of the light of the third wavelength having a shorter wavelength of 2 is larger, the intensity of the three kinds of light emitted from the emission surface can be made uniform.

As a result, in this optical waveguide, three kinds of light can be incident with ease and accuracy, and they can be merged to emit combined light having excellent optical characteristics.

The invention (2) includes the optical waveguide according to (1), wherein the light of the first wavelength includes red light, the light of the second wavelength includes green light, and the light of the third wavelength includes blue light.

In this optical waveguide, since the light of the first wavelength includes red light, the light of the second wavelength includes green light, and the light of the third wavelength includes blue light, it is possible to emit red light and green light with uniform intensity from the emission surface. , And red light. Therefore, it is possible to emit confluent light having a desired hue.

The present invention (3) includes the optical waveguide according to (1) or (2), wherein the confluence part includes a first confluence part for the light of the first wavelength, the light of the second wavelength, and the third wavelength. Any two types of light confluence among the light; and a second confluence part disposed on the downstream side of the transmission direction of the first confluence part, and the light for the remaining part and the light confluence that has converged at the first confluence part. .

In this optical waveguide, two kinds of light are merged in the first confluence portion, and the remaining light and the light that has converged in the first confluence portion are merged in the second confluence portion. Therefore, the number of confluences can be increased to obtain light. Uniformity.

The present invention (4) includes the optical waveguide according to (1) or (2), wherein the merging section includes a full merging section, and the full merging section is provided with the light of the first wavelength, the light of the second wavelength, and the light Three types of light of the third wavelength combine.

In this optical waveguide, since three kinds of light are combined at the full confluence part, it is useful when it is desired to reduce the loss at the confluence part.

The present invention (5) includes the optical waveguide according to any one of (1) to (4), wherein a first optical path length L1 from the first incident surface to the exit surface is relative to the second incident surface The second optical path length L2 up to the exit surface is longer, and the second optical path length L2 is longer than the third optical path length L3 from the third incident surface to the exit surface.

In this optical waveguide, since the first optical path length L1 is longer than the second optical path length L2, it is possible to reliably reduce the first attenuation ratio R1 of the light of the first wavelength to a length shorter than that of the first wavelength. The second attenuation ratio R2 of the light of the second wavelength is set to be large.

In addition, since the second optical path length L2 is longer than the third optical path length L3, the second attenuation ratio R2 can be reliably compared with the third attenuation ratio R3 of the third wavelength light shorter than the second wavelength. Set larger.

As a result, a simple configuration in which the first optical path length L1, the second optical path length L2, and the third optical path length L3 are shortened in this order can be used to reliably form the three kinds of light emitted from the emission surface to have a uniform intensity.
The present invention (6) includes the optical waveguide according to any one of (1) to (5), in which the first leakage ratio LR1 when the light of the first wavelength is transmitted from the first incident surface to the exit surface is relatively The second leakage ratio LR2 when the light at the second wavelength is transmitted from the second incidence surface to the exit surface is large, and the second leakage ratio LR2 is from the third incidence surface with respect to the light of the third wavelength. The third leakage ratio LR3 when transmitting to the exit surface is large.

In this optical waveguide, since the first leakage ratio LR1 is larger than the second leakage ratio LR2, the first attenuation ratio R1 of the light of the first wavelength can be reliably compared with the first attenuation ratio R1 that is shorter than the first wavelength. The second attenuation ratio R2 of the two-wavelength light is set to be large.

In addition, since the second leakage ratio LR2 is larger than the third leakage ratio LR3, the second attenuation ratio R2 can be reliably compared with the third attenuation ratio R3 of the light of the third wavelength shorter than the second wavelength. Set larger.

As a result, the first leakage ratio LR1, the second leakage ratio LR2, and the third leakage ratio LR3 can be made smaller in this order, so that the intensities of the three types of light emitted from the emission surface can be uniformly formed.

The present invention (7) includes the optical waveguide according to any one of (1) to (6), wherein the core material includes a first core material portion which is arranged upstream of a transmission direction of the confluence portion, and transmits the incident light to Light of the first wavelength at the first incident surface;
The second core material portion is disposed upstream of the confluence portion in the transmission direction and transmits light of the second wavelength incident on the second incidence surface; and the third core material portion is disposed upstream of the confluence portion in the transmission direction. Side and transmits the light of the third wavelength incident on the third incident surface,
Each of the first core material portion and the second core material portion has a shape in which an opening cross-sectional area becomes smaller as it goes toward the downstream side in the transport direction.
The third core material portion has a shape in which the opening cross-sectional area becomes smaller as it goes toward the downstream side in the conveying direction, or the opening cross-sectional area is the same shape,
In the first core material portion, the first opening cross-sectional area OS1 in the end edge on the downstream side of the conveying direction facing the confluence portion is larger than the conveyance direction of the first core material portion facing the confluence portion in the second core material portion. The second cross-sectional area OS2 of the downstream end edge is small,
The second opening cross-sectional area OS2 is smaller than the third opening cross-sectional area OS3 in the end edge on the downstream side of the transport direction facing the merging portion in the third core material portion.

In this optical waveguide, since the first opening cross-sectional area OS1 is smaller than the second opening cross-sectional area OS2, the first leakage ratio LR1 can be set larger than the second leakage ratio LR2.

In addition, since the second opening cross-sectional area OS2 is smaller than the third opening cross-sectional area OS3, the second leakage ratio LR2 can be set larger than the third leakage ratio LR3.

As a result, the first leakage cross-sectional area OS1, the second opening cross-sectional area OS2, and the third opening cross-sectional area OS3 can be reduced in this order to make the first leakage ratio LR1, the second leakage ratio LR2, and the like. The third leakage ratio LR3 becomes smaller in this order.

The invention (8) includes the optical waveguide according to any one of (1) to (6), wherein the first incident surface and the second incident surface are both arranged to project light onto the first incident surface. When the direction of the surface and the second incident surface is staggered from the exit surface, the third incident surface is arranged so that when the light is projected in a direction incident on the third incident surface, the same position as the exit surface or The aforementioned exit surface is staggered,
The first optical path from the first incident surface to the exit surface in the core material has a first curved portion,
The second optical path from the second incident surface to the exit surface in the core material has a second curved portion,
The third optical path from the third incident surface to the exit surface in the core material has a straight portion or a third curved portion,
The first curved portion is curved relatively to the second curved portion.
The second bent portion is bent larger than the third bent portion.

In this optical waveguide, since the first bent portion is bent relatively with respect to the second bent portion, the first leakage ratio LR1 can be set larger than the second leakage ratio LR2.

In addition, since the second bending portion is bent relatively to the third bending portion, the second leakage ratio LR2 can be set to be larger than the third leakage ratio LR3.

As a result, a simple configuration in which the first curved portion and the second curved portion are increased in this order, or a simple configuration in which the first curved portion, the second curved portion, and the third curved portion are increased in this order can be used. To reduce the first leakage ratio LR1, the second leakage ratio LR2, and the third leakage ratio LR3 in this order.

The present invention (9) includes the optical waveguide according to any one of (1) to (8), wherein the core material contains a first light absorber and a second light absorber,
So that the first attenuation ratio R1 becomes larger than the second attenuation ratio R2, and the second attenuation ratio R2 becomes larger than the third attenuation ratio R3,
The first light absorber is a light absorber that locally absorbs light of the first wavelength, and the second light absorber is a light absorber that locally absorbs light of the second wavelength.

The core material contains a first light absorbing agent and a second light absorbing agent so that the first attenuation ratio R1 becomes larger than the second attenuation ratio R2, and the second attenuation ratio R2 becomes larger than the third attenuation ratio R3. Get bigger. Therefore, the intensities of the three kinds of light emitted from the emission surface can be made uniform.

The present invention (10) includes the optical waveguide according to any one of (1) to (9), wherein the first wavelength of light is made incident on the first incident surface, and the light having the same wavelength as the first wavelength of light is incident. When light of the second wavelength of the same intensity is incident on the second incident surface, and light of the third wavelength having the same intensity as the light of the second wavelength is incident on the third incident surface,
The ratio (I1 / I2) of the first intensity I1 of the light of the first wavelength to the second intensity I2 of the light of the second wavelength emitted from the exit surface is 0.6 or more and 1.4 or less, and the first intensity I1 The ratio (I1 / I3) of the third intensity I3 to the light of the third wavelength is 0.6 or more and 1.4 or less.

In this optical waveguide, the ratio (I1 / I2) of the first intensity I1 of the light of the first wavelength to the second intensity I2 of the light of the second wavelength is 0.6 or more and 1.4 or less, and the first intensity I1 and the third Since the ratio (I1 / I3) of the third intensity I3 of the light of the wavelength is 0.6 or more and 1.4 or less, three kinds of light can be emitted with uniform intensity.
Invention effect

The optical waveguide of the present invention can simply and accurately feed three kinds of light, and make them converge to emit combined light with excellent optical characteristics.

Embodiment for Implementing the Invention <First Embodiment>
A first embodiment of the optical waveguide of the present invention will be described with reference to FIGS. 1 to 3C. In addition, in FIGS. 1 and 3A, 3B, and 3C, in order to clearly show the arrangement of the core material 2 (to be described later), the upper cladding material 4 (to be described later) is omitted.

This optical waveguide 10 is a light coupling element that allows three (three) types of light having different wavelengths to be incident and made to converge, and then one light that has been converged is emitted.

As shown in FIGS. 1 and 2A and 2B, the optical waveguide 10 has a substantially rectangular shape in a planar viewing angle, and has a light transmission direction (left-right direction of the paper surface in FIG. 1) (hereinafter, sometimes referred to simply as a transmission direction) An approximately sheet shape (or approximately a plate shape) extending upward.
Specifically, the optical waveguide 10 includes an upstream end surface 5 and a downstream end surface 6 facing each other in the transmission direction, and a width direction (hereinafter, simply referred to as a width direction) orthogonal to the transmission direction and the thickness direction facing each other. And connect one end surface 7 in the width direction and one end surface 8 in the width direction at both ends in the width direction of the upstream end surface 5 and the downstream end surface 6.

The upstream-side end surface 5 is a side surface extending in the width direction.

The downstream-side end surface 6 is a side surface in the width direction. The downstream-side end surface 6 is parallel to the upstream-side end surface 5.

One end surface 7 in the width direction and the other end surface 8 in the width direction are side surfaces facing each other in the width direction. One end surface 7 in the width direction and the other end surface 8 in the width direction are parallel to each other along the transport direction.

Furthermore, the optical waveguide 10 further has a flat upper surface 55 and a lower surface 56.

This optical waveguide 10 is a band-type optical waveguide, and includes a covering material 1 and a core material 2 embedded in the covering material 1.

The covering material 1 has the same shape as the optical waveguide 10 when projected in the thickness direction. The covering material 1 has a substantially sheet shape that is substantially rectangular in a plan view. Specifically, the covering material 1 includes a lower covering material 3 and an upper covering material 4 arranged on the lower covering material 3.

The lower cladding material 3 is a lower layer in the cladding material 1 and forms a lower surface 56 of the optical waveguide 10.

The upper cladding material 4 is an upper layer in the cladding material 1 and forms an upper surface 55 of the optical waveguide 10. The lower surface of the upper cladding material 4 is in contact with the upper surface and side surfaces of the core material 2 described later.

Examples of the material of the covering material 1 include transparent resins such as epoxy resin. The thickness of the cladding material 1 is the same as the thickness of the optical waveguide 10, and is the total thickness of the lower cladding material 3 and the upper cladding material 4. The thickness of the covering material 1 is, for example, 10 μm or more, preferably 50 μm or more, and, for example, 1000 μm or less, and preferably 200 μm or less.

The core material 2 is buried in the covering material 1. Specifically, the core material 2 is arranged on the upper surface of the lower covering material 3 and is covered with the upper covering material 4.

The core material 2 is integrally provided with three optical paths (the first optical path 21 described later (refer to the highlighted display portion of FIG. 3A), the second optical path 22 (refer to the highlighted display portion of FIG. 3B), and the third optical path 23 (refer to FIG. 3). 3C emphasizes the display part)), a merging section 16 for merging the three optical paths, and a merging path 25 arranged on the downstream side in the transmission direction.

The thickness T (length in the vertical direction) of the core material 2 is the same in any portion. The thickness T of the core material 2 is, for example, 5 μm or more, preferably 10 μm or more, and also, for example, 500 μm or less, and preferably 100 μm or less.

As shown in FIGS. 3A to 3C, the three optical paths are optical paths that transmit three types of light having different wavelengths, that is, the first optical path 21, the second optical path 22, and the third optical path 23. The first optical path 21 transmits the first light, the second optical path 22 transmits the second light, and the third optical path 23 transmits the third light.

The first light is light having a relatively long first wavelength and includes light having a wavelength of, for example, 580 nm or more, preferably 600 nm or more, and 700 nm or less, and specifically includes red light. The second light is light of a second wavelength shorter than the first wavelength, and includes light having a wavelength of, for example, less than 580 nm, preferably 550 nm or less, and, for example, 485 nm or more, preferably 500 nm or more, specifically, Words contain green light. The third light is light of a third wavelength shorter than the second wavelength, and includes light having a wavelength of, for example, less than 485 nm, preferably 470 nm or less, and, for example, 400 nm or more, and preferably 420 nm or more. Words contain blue light.

The end face in the transmission direction upstream of the first optical path 21 is the first incident surface 11 and is exposed from the taper surface 9. Specifically, the first incident surface 11 and the tapered surface 9 are flush with each other. The first incident surface 11 is an incident surface on which the first light is incident on the first optical path 21.

As shown in FIG. 2A, the first incident surface 11 has a substantially rectangular shape when viewed from the upstream side in the transmission direction (hereinafter referred to as a front viewing angle). The first area S1 of the first incident surface 11 is a value obtained by multiplying the width W1 of the core material 2 along the tapered surface 9 by the thickness T.

As shown in FIG. 3A, the first optical path 21 includes a first core portion 26 including a first incident surface 11. The first core material portion 26 is an end portion located on the upstream side in the transmission direction in the first optical path 21. The first core portion 26 is an optical path in the first optical path 21 for transmitting only the first light incident on the first incident surface 11. The first core material portion 26 has a substantially linear shape extending from the first incidence surface 11 toward the downstream side in the transmission direction. It should be noted that the transmission direction is based on the transmission direction of light in the full-combination path 30 described later. In detail, the first core portion 26 extends obliquely toward the width direction and extends toward one side of the width direction. Specifically, the first core portion 26 is inclined with respect to the conveyance direction so as to gradually approach the width direction as it advances toward the downstream side of the conveyance direction. One side end face 7. Further, a merging section 16 described later is disposed at the downstream end of the first core material section 26 in the transmission direction, and a first optical path 21 is provided with a merging path 25 described later on the downstream side in the transmission direction of the merging section 16. (Described later).

As shown in FIG. 3B, the end face in the transmission direction upstream side of the second optical path 22 is the second incident surface 12 and is exposed from the upstream end face 5. The second incident surface 12 is flush with the upstream end surface 5. The second incidence surface 12 is disposed with a gap therebetween on one side in the width direction of the first incidence surface 11. The second incident surface 12 is an incident surface on which the second light is incident on the second optical path 22.

As shown in FIG. 2A, the second incident surface 12 and the first incident surface 11 have the same shape. Therefore, the second area S2 of the second incident surface 12 is the same as the first area S1, specifically, a value obtained by multiplying the width W2 of the core material 2 along the upstream end surface 5 by the thickness T. In detail, since the thickness T of the core material 2 is the same in the first optical path 21 and the second optical path 22, the width W2 of the second incident surface 12 and the width W1 of the first incident surface 11 are the same.

As shown in FIG. 3B, the second optical path 22 includes a second core portion 27 including a second incident surface 12. The second core portion 27 is an end portion located on the upstream side in the transmission direction in the second optical path 22. The second core portion 27 is an optical path in the second optical path 22 for transmitting only the second light incident on the second incident surface 12. The second core portion 27 has a substantially linear shape extending straight from the second incidence surface 12 toward the downstream side in the transmission direction. In addition, a merging section 16 described later is disposed at the downstream end of the second core member section 27 in the transmission direction, and the second optical path 22 is disposed downstream of the merging section 16 in the transmission direction in common with the first optical path 21的 合流 路 25 (to be described later).

As shown in FIG. 3C, the end face on the upstream side in the transmission direction of the third optical path 23 is the third incident surface 13 and is exposed from the end face 5 on the upstream side. Specifically, the third incident surface 13 is flush with the upstream end surface 5. The third incidence surface 13 is arranged with a gap on one side in the width direction of the second incidence surface 12. That is, the third incident surface 13 is spaced apart from the first incident surface 11 and the second incident surface 12 on one side in the width direction. The third incident surface 13 is an incident surface on which the third light is incident on the third optical path 23.

As shown in FIG. 2A, the third incident surface 13 and the second incident surface 12 have the same shape. Therefore, the third area S3 of the third incident surface 13 is the same as the second area S2, specifically, the value of the width W3 of the core material 2 along the upstream end surface 5 times the thickness T. In detail, since the thickness T of the core material 2 is the same in the second optical path 22 and the third optical path 23, the width W3 of the third incident surface 13 and the width W2 of the second incident surface 12 are the same. That is, the first area S1 of the first incident surface 11, S2 of the second incident surface 12, and S3 of the third incident surface 13 are the same.

As shown in FIG. 3C, the third optical path 23 includes a third core material portion 28, and the third core material portion 28 includes a third incident surface 13. The third core portion 28 is an end portion located on the upstream side in the transmission direction in the third optical path 23. The third core portion 28 is an optical path in the third optical path 23 for transmitting only the third light incident on the third incident surface 13. The third core material portion 28 has a substantially linear shape extending straight from the third incidence surface 13 toward the downstream side in the transmission direction. Further, a merging section 16 described later is arranged at the downstream end of the third core member section 28 in the transmission direction, and the third optical path 23 is arranged downstream from the first optical path 21 in the transmission direction of the merging section 16. A merging path 25 (second merging portion 18) that is common to the second optical path 22.

As shown in FIGS. 1 and 3A to 3C, the merging unit 16 is provided with a first merging portion 17 and a second merging portion 18 independently.

The first confluence portion 17 is a portion where the first optical path 21 and the second optical path 22 are unified for the first time, and is the downstream end portion of the first core material portion 26 in the transmission direction and the downstream portion of the second core material portion 27 in the transmission direction. Part of the side end collection. In other words, the first merging portion 17 is disposed on the downstream end portion in the transport direction of the first core material portion 26 and the second core material portion 27. That is, the first merging portion 17 is disposed on the downstream side in the transmission direction of the first incident surface 11 and the second incident surface 12. In the first confluence part 17, the first light and the second light are merged.

The second merging portion 18 is arranged at intervals on the downstream side in the conveying direction of the first merging portion 17. Specifically, the second merging portion 18 is disposed on the downstream side in the transmission direction of the first merging portion 17 via the intermediate merging path 29 on the downstream side in the transmission direction where the first optical path 21 and the second optical path 22 have merged. The second merging portion 18 is a section where the first optical path 21, the second optical path 22, and the third optical path 23 are unified for the first time, and is the downstream end portion and the third core in the transmission direction of the intermediate merging path 29 (described later). The portion where the downstream end portions of the material portion 28 meet in the transport direction. In other words, the second merging portion 18 is disposed at the downstream-side end portion in the transport direction of the intermediate merging path 29 and the third core material portion 28. That is, the second merging portion 18 is disposed on the downstream side in the transmission direction of the first incident surface 11, the second incident surface 12, and the third incident surface 13. In the second confluence part 18, the first light, the second light, and the third light are merged for the first time.

The merging path 25 includes an intermediate merging path 29 and a full merging path 30.

The intermediate merging path 29 is disposed between the first merging portion 17 and the second merging portion 18, and optically connects (connects) them. The intermediate junction path 29 is an optical path common to the central portion in the transmission direction of the first optical path 21 and the central portion in the transmission direction of the second optical path 22. The intermediate merging path 29 is disposed on an extension line of the first core material portion 26 and has the same shape as the first core material portion 26. On the other hand, the intermediate merging path 29 has an angle with respect to the second core material portion 27, and the angle Y formed by the intermediate merging path 29 and the second core material portion 27 is, for example, 170 degrees or more, preferably 175 degrees or more, and more It is preferably 177 degrees or more, and is, for example, less than 180 degrees.

The full merging path 30 is disposed downstream of the second merging portion 18 in the transmission direction, and is optically connected (connected) to the second merging portion 18. The all-combining path 30 is an optical path common to the downstream end portion of the first optical path 21 in the transmission direction, the downstream end portion of the second optical path 22 in the transmission direction, and the downstream end portion of the third optical path 23 in the transmission direction. The all-combined flow path 30 is disposed on an extension line of the third core material portion 28 and has the same shape as the third core material portion 28. On the other hand, the full merge path 30 has an angle with respect to the intermediate merge path 29, and the angle Z formed by the full merge path 30 and the intermediate merge path 29 is, for example, 170 degrees or more, preferably 175 degrees or more, and more preferably 177 degrees The above is, for example, less than 180 degrees.

As shown in FIGS. 1 and 2B, the end face on the downstream side in the transmission direction of the all-combination channel 30 is the exit surface 14. The exit surface 14 is disposed on the downstream side in the transport direction of the second merging portion 18 (the merging portion 16). The exit surface 14 is exposed from the downstream end surface 6. Specifically, the exit surface 14 is flush with the downstream end surface 6. The exit surface 14 is a light from which the total merging light (to be described later) which has been merged at the second merging portion 18 (the merging portion 16) is emitted.

Therefore, the core material 2 includes the first incidence surface 11, the second incidence surface 12, the third incidence surface 13, and the emission surface 14, and further includes the first confluence portion 17 and the second confluence portion 18. Therefore, the light incident on the first incident surface 11, the second incident surface 12, and the third incident surface 13 is emitted from the emission surface 14 after the first and second confluence portions 17 and 18 (the confluence portion 16) converge. .

Any one of the first incident surface 11, the second incident surface 12, and the third incident surface 13 of the core material 2 is an upstream end surface 5 disposed in the optical waveguide 10. On the other hand, the emission surface 14 of the core material 2 is It is arranged on the downstream side end surface 6 in the optical waveguide 10. The third incident surface 13 overlaps with the outgoing surface 14 (located at the same position) when projected in the transmission direction. On the other hand, the first incident surface 11 and the second incident surface 12 are in the above-mentioned transmission direction ( In detail, it is the direction in which the third light is transmitted.) When projecting, it does not overlap with the exit surface 14 and deviates from the other side in the width direction. In addition, the first incident surface 11 is located relative to the second incident surface 12. Farther away.

As shown in FIGS. 3A to 3C, the length L1 of the first optical path 21, that is, the length L1 of the first optical path from the first incident surface 11 to the exit surface 14, is also relative to the length L2 of the second optical path 22. That is, the second optical path length L2 from the second incident surface 12 to the outgoing surface 14 is longer (L1> L2), and the second optical path length L2 is relative to the length L3 of the third optical path 23, that is, from the third incidence The third optical path length L3 from the surface 13 to the emission surface 14 is long (L2> L3). That is, L1> L2> L3 is satisfied.

The ratio (L1 / L2) of the first optical path length L1 to the second optical path length L2 is, for example, 1.001 or more, preferably 1.01 or more, more preferably 1.1 or more, and, for example, 2 or less.

The ratio (L2 / L3) of the second optical path length L2 to the third optical path length L3 is, for example, 1.001 or more, preferably 1.01 or more, more preferably 1.1 or more, and, for example, 2 or less.

The ratio (L1 / L3) of the first optical path length L1 to the third optical path length L3 is, for example, 1.002 or more, preferably 1.02 or more, more preferably 1.15 or more, and, for example, 3 or less.

Examples of the material of the core material 2 include a transparent resin similar to the material of the covering material 1. The refractive index of the core material 2 is higher than the refractive index of the cladding material 1. In addition, the refractive index and light transmittance of the core material 2 are adjusted to be uniform (same) covering the transmission direction. That is, the core material 2 is optically homogeneous covering the transmission direction.

In order to obtain the optical waveguide 10, for example, the lower cladding material 3 is first prepared, and then the core material 2 is formed on the upper surface of the lower cladding material 3 by photolithography or the like, and then the upper cladding material 4 is formed on The upper surface of the lower cladding material 3 covers the upper surface and side surfaces of the core material 2.

Then, in this optical waveguide 10, for example, each of the first light, the second light, and the third light is made incident on the first incident surface 11, the second incident surface 12, and the third incident surface 13 by the light emitting device 65. Every.

The light emitting device 65 includes a first light emitting section 61 that emits first light, a second light emitting section 62 that emits second light, and a third light emitting section 63 that emits third light.

The first light emitting portion 61 is substantially opposed to the first incident surface 11. Specifically, the first light-emitting portion 61 is disposed to face the first incident surface 11 in a direction along the first optical path 26 in the first core portion 26. However, the emission side surface of the first light emitting portion 61 is not parallel to the first incidence surface 11 and faces obliquely.

The second light emitting section 62 is disposed opposite to the second incident surface 12 in the transmission direction.

The third light emitting section 63 is disposed opposite to the third incident surface 13 in the transmission direction.

As described above, the light emitting device 65 is positioned with respect to the upstream end surface 5.

In this way, each of the first light, the second light, and the third light is transmitted along each of the optical paths of the first optical path 21, the second optical path 22, and the third optical path 23, and merges on the way The parts 16 merge and emit from the exit surface 14 together.

Specifically, the first light transmitted from the first incidence surface 11 in the first core material portion 26 and the second light transmitted from the second incidence surface 12 in the second core material portion 27 are reflected in The first merging portion 17 merges to synthesize the intermediate merging light.

The intermediate converging light and the third light transmitted from the third incident surface 13 in the third core material portion 28 converge at the second converging portion 18 to synthesize the total converging light.

The fully-combined light will be transmitted in the fully-combined path 30 and then emitted from the exit surface 14.

In addition, since the lengths of the respective optical paths of the first optical path 21, the second optical path 22, and the third optical path 23 satisfy L1> L2> L3, the first attenuation of the first light incident on the first incident surface 11 and emitted from the exit surface 14 The ratio R1 is larger than the second attenuation ratio R2 of the second light incident on the second incidence surface 12 and emitted from the exit surface 14, and the second attenuation ratio R2 is higher than the incidence on the third incidence. The third attenuation ratio R3 of the third light emitted from the surface 13 and from the emission surface 14 is large.

That is, the following formula (1) is satisfied.

1st attenuation ratio R1> 2nd attenuation ratio R2> 3rd attenuation ratio R3 (1)
On the other hand, if the expression (1) is not satisfied, the three kinds of light emitted from the emission surface 14 cannot be made uniform in intensity.

The ratio (R1 / R2) of the first attenuation ratio R1 of the first light to the second attenuation ratio R2 of the second light is, for example, 1.001 or more, preferably 1.01 or more, more preferably 1.1 or more, and, for example, 2 or less .

The ratio (R2 / R3) of the second attenuation ratio R2 of the second light to the third attenuation ratio R3 of the third light is, for example, 1.001 or more, preferably 1.01 or more, more preferably 1.1 or more, and, for example, 2 or less .

The ratio (R1 / R3) of the first attenuation ratio R1 of the first light to the third attenuation ratio R3 of the third light is, for example, 1.002 or more, preferably 1.02 or more, more preferably 1.15 or more, and, for example, 3 the following.

As long as the above-mentioned ratio is above the above-mentioned lower limit, the intensity of the three kinds of light emitted from the emission surface 14 can be made uniform.

Therefore, the first light is made incident on the first incident surface 11, the second light having the same intensity as the first light is made incident on the second incident surface 12, and the third light having the same intensity as the second light is made incident From the third incident surface 13, the ratio (I1 / I2) of the first intensity I1 of the first light emitted from the emission surface 14 to the second intensity I2 of the second light is 0.6 or more and 1.4 or less, and the first The ratio (I1 / I3) of the intensity I1 to the third intensity I3 of the third light is 0.6 or more and 1.4 or less.

The ratio (I1 / I2) of the first intensity I1 to the second intensity I2 and the ratio (I1 / I3) of the first intensity I1 to the third intensity I3 are preferably 0.8 or more, more preferably 0.9 or more, It is preferably 1.2 or less, and more preferably 1.1 or less.

As long as the intensity ratio is above the lower limit and below the upper limit, three kinds of light can be emitted with uniform intensity.

Then, in this optical waveguide 10, each of the first light, the second light, and the third light is incident on the first incident surface 11, the second incident surface 12, and the third incident surface 13, and the light is incident on the second incident surface. The confluence part 18 (convergence part 16) merges three kinds of light and emits three kinds of light from the emission surface 14.

In addition, since the first area S1 of the first incident surface 11, the second area S2 of the second incident surface 12, and the third area S3 of the third incident surface 13 are the same, the light emitting device 65 and the first The first incident surface 11, the second incident surface 12, and the third incident surface 13 are aligned, and the two can be easily optically connected.

In addition, the first attenuation ratio R1 of the first light is larger than the second attenuation ratio R2 of the second light having a shorter wavelength than the first light, and the second attenuation ratio R2 is larger than the wavelength of the second light. Since the third attenuation ratio R3 of the shorter third light is large (R1> R2> R3), the intensity of the three kinds of light emitted from the emission surface 14 can be made uniform.

As a result, in the optical waveguide 10, three kinds of light of the first light, the second light, and the third light can be made incident with ease and accuracy, and the all-combined light having excellent optical characteristics can be emitted while being made to converge.

In this optical waveguide 10, since the first light includes red light, the second light includes green light, and the third light includes blue light, red light, green light, and blue light can be emitted from the emission surface 14 with uniform intensity. Therefore, a total confluent light having a desired hue can be emitted.

In this optical waveguide 10, the first light and the second light are merged at the first confluence portion 17, and the remaining light, that is, the third light, is converged at the second confluence portion 18, and the light has already converged at the first confluence portion 17. In the middle, the light merges, so the number of merges can be increased to achieve uniformity of light.

In this optical waveguide 10, since the first optical path length L1 is longer than the second optical path length L2, the first attenuation ratio R1 of the first light can be reliably compared with the second attenuation ratio of the second light. R2 is set larger.

In addition, since the second optical path length L2 is longer than the third optical path length L3, it is possible to reliably set the second attenuation ratio R2 to be larger than the third attenuation ratio R3 of the third light.

As a result, a simple configuration in which the first optical path length L1, the second optical path length L2, and the third optical path length L3 are shortened in this order can be used to reliably form the three types of light emitted from the emission surface 14 into a uniform intensity. .

In this optical waveguide 10, the ratio (I1 / I2) of the first intensity I1 of the first light to the second intensity I2 of the second light is 0.6 or more and 1.4 or less, and the first intensity I1 and the third intensity I1 The ratio (I1 / I3) of the three intensities I3 is 0.6 or more and 1.4 or less, so that three kinds of light can be emitted with a uniform intensity.

＜ Modifications ＞
In each of the following modifications, the same reference numerals are assigned to the same members as those in the first embodiment described above, and detailed descriptions thereof are omitted. In addition, except for the special description, each modification can exhibit the same function and effect as those of the first embodiment.

The first area S1 of the first incident surface 11, the second area S2 of the second incident surface 12, and the third area S3 of the third incident surface 13 may be substantially the same, and there may be slight differences, for example, as described below. : To the extent that it does not interfere with the positioning of the above-mentioned light emitting device 65 and the first incident surface 11, the second incident surface 12, and the third incident surface 13. Specifically, the width W1 of the first incident surface 11, the width W2 of the second incident surface 12, and the width W3 of the third incident surface 13 may be substantially the same, and in detail, the following ranges are allowed: W1 / W2 and W1 / W3 are, for example, 0.9 or more, preferably 0.95 or more, and, for example, 1.1 or less, and preferably 1.01 or less.

Moreover, in the first embodiment, in the first confluence part 17, the first light path 21 and the second light path 22 are merged into one, and the first light path and the second light are converged, but as long as the first light Any of two kinds of light, the second light, and the third light may be combined. Although not shown, in the first confluence part 17, for example, the first light path 21 and the third light path 23 may be merged into one, and the first light and the third light may be merged. The second light path 22 and the third light path 23 are merged into one, and the second light and the third light are merged.

In addition, the core material 2 contains a first light absorber and a second light absorber so that the first attenuation ratio R1 becomes larger than the second attenuation ratio R2, and the second attenuation ratio R2 becomes larger than the third attenuation. The ratio R3 becomes larger. The first light absorber is a light absorber that locally absorbs the first light, and the second light absorber is a light absorber that locally absorbs the second light.

Examples of the first light absorber include a red light absorber. Specific examples include anthraquinone-based compounds, phthalocyanine-based compounds, cyanine-based compounds, polymethylene compounds, aluminum-based compounds, and diene. Ammonium-based compounds, imonium-based compounds, azo-based compounds, and the like.

Examples of the second light absorber include a green light absorber, and specifically, an anthraquinone-based compound, a phthalocyanine-based compound, and the like.

In addition, the core material 2 may contain a third light absorber in addition to the first light absorber and the second light absorber, so that the second attenuation ratio R2 becomes larger than the third attenuation ratio R3. The third light absorber is a light absorber that locally absorbs the third light.

Examples of the third light absorber include a blue light absorber, and specific examples thereof include a benzotriazole-based compound, a diphenyl ketone-based compound, a salicylic acid-based compound, and a coumarin-based compound.

The content ratios of the first light absorber and the second light absorber can be appropriately adjusted to satisfy the relationship of the first attenuation ratio R1> the second attenuation ratio R2> the third attenuation ratio R3.

Further, in this modification, the core material 2 contains the first light absorber and the second light absorber so as to satisfy the relationship of the first attenuation ratio R1> the second attenuation ratio R2> the third attenuation ratio R3. Therefore, the intensities of the three kinds of light emitted from the emission surface 14 can be made uniform.

In the first embodiment, the upstream end surface 5 is configured as one plane (side surface). However, as shown in FIG. 4, the inclined surface 9 may be formed on the upstream end surface 5.

In this modification, the tapered surface 9 is formed by cutting the other end portion in the width direction of the upstream end surface 5 obliquely. In the upstream end surface 5, the angle X formed by the tapered surface 9 and the widthwise central portion and one end portion in the widthwise direction is an obtuse angle, and the tapered surface 9 can be set parallel to a third incident surface 13 described later, specifically, Is, for example, 170 degrees or more, preferably 175 degrees or more, more preferably 177 degrees or more, and, for example, less than 180 degrees.

The first area S1 of the first incident surface 11 is the same as the second area S2 of the second incident surface 12 and the third area S3 of the third incident surface 13, and the width W1 of the first incident surface 11 is along the tapered surface. 9 direction length.

The first light-emitting portion 61 is disposed opposite to the tapered surface 9 including the first incident surface 11.

In the first embodiment, the merging portion 16 includes two portions, a first merging portion 17 and a second merging portion 18. However, as shown in FIG. 5, the number of the merging portions 16 may be one. Specifically, the merging unit 16 includes only a full merging unit 19 for merging three kinds of light of the first light, the second light, and the third light.

The all-combined portion 19 is a portion where the downstream end portion of the first core material portion 26 in the conveyance direction, the downstream end portion of the second core material portion 27 in the conveyance direction, and the downstream end portion of the third core material portion 28 in the conveyance direction. . In the total confluence unit 19, three types of light of the first light, the second light, and the third light are combined to synthesize the total confluence light.

The merging path 25 does not include the intermediate merging path 29 (see FIG. 1), and includes only the full merging path 30. The full-combination path 30 transmits the full-combination light synthesized in the full-combination section 19 toward the exit surface 14.

The second core material portion 27 has a shape extending from the second incident surface 12 toward the total merging channel 30. The second core material portion 27 is inclined similarly to the first core material portion 26. However, the degree of inclination of the second core material portion 27 is smaller than the degree of inclination of the first core material portion 26. Specifically, the inclination of the second core material portion 27 (specifically, the second core) The angle α2 between the material portion 27 and the first core material portion 26) with respect to the inclination of the first core material portion 26 (specifically, the angle α1 between the first core material portion 26 and the first core material portion 26) The ratio (α2 / α1) is, for example, 0.9 or less, preferably 0.8 or less, more preferably 0.7 or less, and, for example, 0.1 or more.

Further, as shown in FIG. 6, the upstream end surface 5 may be formed into a substantially stepped shape in a plan view. The upstream end surface 5 is provided with the first surface 51, the second surface 52, and the third surface 53 independently. The first surface 51 includes the first incident surface 11, the second surface 52 includes the second incident surface 12, and the first The three surfaces 53 include a third incident surface 13.

When the first surface 51, the second surface 52, and the third surface 53 are projected in the width direction, they are arranged at intervals in the transmission direction, and are arranged in this order toward the downstream side in the transmission direction. Therefore, among the upstream-side end surface 5, the first surface 51 is disposed farthest from the downstream-side end surface 6, and the third surface 53 is disposed closest to the downstream-side end surface 6. The second surface 52 is located between the first surface 51 and the third surface 53. Each of the first surface 51, the second surface 52, and the third surface 53 is parallel to the downstream end surface 6 in the width direction.

The first surface 51 includes a first incident surface 11.

The second surface 52 includes a second incident surface 12.

The third surface 53 includes a third incident surface 13.

Therefore, L1> L2> L3 can be more surely satisfied.

Specifically, (L1 / L2) is, for example, 1.01 or more, preferably 1.1 or more, more preferably 1.2 or more, and, for example, 5 or less.

The ratio (L2 / L3) of the second optical path length L2 to the third optical path length L3 is, for example, 1.01 or more, preferably 1.1 or more, more preferably 1.2 or more, and 5 or less, for example.

The ratio (L1 / L3) of the first optical path length L1 to the third optical path length L3 is, for example, 1.02 or more, preferably 1.2 or more, more preferably 1.3 or more, and 10 or less, for example.

<Second Embodiment>
In the following second embodiment, the same components as those in the first embodiment and its modification are given the same reference numerals, and detailed descriptions thereof are omitted. In addition, the second embodiment can exhibit the same functions and effects as those of the first embodiment and its modifications, except for the special description.

In the first embodiment and its modification, the first optical path length L1 of the first optical path 21, the second optical path length L2 of the second optical path 22, and the third optical path length L3 of the third optical path 23 are set to satisfy L1. > L2> L3. Thereby, the formula (1) can be satisfied [1st attenuation ratio R1> 2nd attenuation ratio R2> 3rd attenuation ratio R3].

On the other hand, in the second embodiment, as shown in FIG. 7, the first leakage ratio LR1 of the first light, the second leakage ratio LR2 of the second light, and the third leakage ratio LR3 of the third light may be set. It satisfies LR1> LR2> LR3 to satisfy the above formula (1).

Specifically, as shown in FIG. 7, each of the first core material portion 26 and the second core material portion 27 has a shape in which the opening cross-sectional area becomes smaller as it goes toward the downstream side in the conveying direction. More specifically, each of the first core material portion 26 and the second core material portion 27 has a substantially tapered shape in a planar viewing angle when both side surfaces in the width direction approach as they approach the downstream side in the transport direction. The inclination of both sides of the first core material portion 26 in the width direction with respect to the transmission direction (the first angle β1 formed by the imaginary plane along the side surface and the axis along the transmission direction) is greater than that of the second core material portion 27 The inclination of the two sides in the width direction with respect to the transmission direction (the angle β2 formed by the imaginary plane along the side and the axis along the transmission direction) is large. Specifically, the ratio (β1 / β2) is For example, 1.001 or more, preferably 1.01 or more, more preferably 1.1 or more, and, for example, 2 or less.

On the other hand, the third core portion 28 has a shape having the same opening cross-sectional area as it goes toward the downstream side in the conveying direction. Specifically, the third core portion 28 has a substantially linear shape in a planar viewing angle along the transmission direction.

Therefore, the first opening cross-sectional area OS1 in the downstream end edge (first downstream side end edge 31) of the transport direction facing the first merging portion 17 (merging portion 16) in the first core portion 26 is compared with In the second core portion 27, the second opening cross-sectional area OS2 in the downstream end edge of the conveying direction facing the first merging portion 17 (merging portion 16) is small. Specifically, the width W4 of the first downstream-side end edge 31 is narrower than the width W5 of the second downstream-side end edge 32.

In this way, because the first core material portion 26 and the second core material portion 27 have a substantially conical shape in a plane viewing angle, the first light and Each light of the second light is liable to leak. In addition, since the width W4 of the first downstream-side end edge 31 is narrower than the width W5 of the second downstream-side end edge 32, the first core material portion 26 The leakage ratio of the first light is larger than the leakage ratio of the second light in the second core portion 27.

On the other hand, the leakage ratio of the first light and the leakage ratio of the second light in the intermediate junction 29 and the full junction 30 (the junction 25) are because the first light and the second light are transmitted in the common junction 25. Light, so it's the same. In this way, the first leakage ratio LR1 when the first light is transmitted from the first incidence surface 11 to the emission surface 14 is relatively larger than the second leakage ratio LR2 when the second light is transmitted from the second incidence surface 12 to the emission surface. Big.

In addition, the second opening cross-sectional area OS2 is smaller than the third opening cross-sectional area OS3 in the downstream side end edge (third downstream side end edge 33) of the transport direction facing the merging portion in the third core portion 28. Specifically, the width W5 of the second downstream-side end edge 32 is narrower than the width W6 of the third downstream-side end edge 33. Therefore, the leakage ratio of the second light in the second core material portion 27 is larger than the leakage ratio of the third light in the third core material portion 28.

On the other hand, the leak rate of the second light and the leak rate of the third light in the all-combined path 30 are the same because the second light and the third light are transmitted in the common all-combined path 30. In this way, the second leakage ratio LR2 when the second light is transmitted from the second incident surface 12 to the exit surface 14 is larger than the third leakage rate when the third light is transmitted from the third incident surface 13 to the exit surface 14. The leakage ratio LR3 is large.

That is, in the optical waveguide 10, the relationship of the first leakage ratio LR1> the second leakage ratio LR2> the third leakage ratio LR3 is satisfied.

In addition, in this optical waveguide 10, since the first leakage ratio LR1 is larger than the second leakage ratio LR2, the first attenuation ratio R1 of the first light can be reliably shorter than the wavelength of the first light. The second attenuation ratio R2 of the second light is set to be large.

In addition, since the second leakage ratio LR2 is larger than the third leakage ratio LR3, it is possible to reliably set the third attenuation ratio R3 of the second attenuation ratio R2 to the third light having a shorter wavelength than the second light. Is bigger.

As a result, a configuration in which the first leakage ratio LR1, the second leakage ratio LR2, and the third leakage ratio LR3 are reduced in this order can be used to reliably uniform the intensity of the three types of light emitted from the emission surface 14.

In addition, in this optical waveguide 10, since the first opening cross-sectional area OS1 is smaller than that of the second opening cross-sectional area OS2, the first leakage ratio LR1 can be set larger than the second leakage ratio LR2.

In addition, since the second opening cross-sectional area OS2 is smaller than the third opening cross-sectional area OS3, the second leakage ratio LR2 can be set larger than the third leakage ratio LR3.

＜ Modifications ＞
In each of the following modifications, the same reference numerals are assigned to the same members as those in the second embodiment described above, and detailed descriptions thereof are omitted. In addition, except for the special description, each modification can exhibit the same function and effect as those of the second embodiment.

As shown in FIG. 7, in the second embodiment, although the third core material portion 28 has a substantially linear shape in a planar viewing angle, for example, although not shown, as long as the third downstream side end edge of the third core material portion 28 The width W6 of 33 may be wider than the width W5 of the second downstream-side end edge 32 in the second core material portion 27, and the third core material portion 28 may have a substantially conical shape in a planar viewing angle.

<Third Embodiment>
In the following third embodiment, the same components as those in the first embodiment, the second embodiment, and the modified examples are given the same reference numerals, and detailed descriptions thereof are omitted. In addition, the third embodiment can exhibit the same functions and effects as those of the first embodiment, the second embodiment, and its modification, except as specifically described.

In the second embodiment and its modification, at least the first core material portion 26 and the second core material portion 27 are formed into a tapered shape. Thereby, Expression (1) is satisfied [the first attenuation ratio R1> the second attenuation ratio R2> the third attenuation ratio R3].

On the other hand, as shown in FIG. 8, in the third embodiment, at least each of the first optical path 21 and the second optical path 22 has a first curved portion 36 and is bent more than the first curved portion 36. The small second bending portion 37. On the other hand, the third optical path 23 includes only the third linear portion 50. Thereby, the above formula (1) can also be satisfied.

Specifically, the first core portion 26 includes a first straight portion 48 and a first bent portion 36.

The first linear portion 48 has a substantially linear shape at a planar viewing angle extending from the first incident surface 11 in the direction in which the first light is incident. The downstream end of the first straight portion 48 in the conveying direction is such that the first bent portion 36 is continuous.

The first bending portion 36 is relatively small in a planar viewing angle. The first bent portion 36 includes a first central portion 38 and a first downstream portion 39.

The first central portion 38 has a center of curvature on one side in the width direction.

The first downstream side portion 39 is disposed downstream of the first central portion 38 in the transmission direction, and has a center of curvature on the other side in the width direction. The first downstream-side portion 39 is disposed downstream of the first central portion 38 in the conveying direction, and continues to the full merge path 30.

The second core material portion 27 includes a second straight portion 49 and a second bent portion 37.

The second straight portion 49 has a substantially straight shape at a planar viewing angle extending in a direction in which the second light is incident from the second incident surface 12. An end portion on the downstream side of the second straight portion 49 in the transmission direction is such that the second bent portion 37 is continuous.

The second curved portion 37 is curved larger than the first curved portion 36 in a planar viewing angle. The second curved portion 37 includes a second central portion 40 and a second downstream side portion 41.

The second central portion 40 has a center of curvature on one side in the width direction, and is curved more than the first central portion 38.

The second downstream-side portion 41 is disposed downstream of the second central portion 40 in the conveying direction, and is bent larger than the first downstream-side portion 39. The second downstream side portion 41 has a center of curvature on the other side in the width direction. The second downstream-side portion 41 is continuous to the full merge path 30.

On the other hand, the third straight portion 50 includes a third incident surface 13 and is parallel to one of the end surfaces 7 in the width direction.

Further, in the optical waveguide 10 according to the third embodiment, the first bent portion 36 is bent larger than the second bent portion 37, so that the first leakage ratio LR1 can be set to be relatively larger than the second leakage ratio LR2. Big.

Since the third optical path 23 is constituted by the third linear portion 50, the second leakage ratio LR2 can be set larger than the third leakage ratio LR3.

As a result, the first leaking ratio LR1, the second leaking ratio can be reduced by a simple structure in which the first opening cross-sectional area OS1, the second opening cross-sectional area OS2, and the third opening cross-sectional area OS3 are reduced in this order. LR2 and the third leakage ratio LR3 become smaller in this order.

＜ Modifications ＞
In the third embodiment, although the third core portion 28 has the third straight portion 50, it may also have a third bent portion that is further smaller than the second bent portion 37, although not shown in the figure, for example. In this case, the third incident surface 13 is arranged so as to be offset from the outgoing surface 14 when projecting in the transmission direction.

As shown in FIG. 9, each of the first bent portion 36 and the second bent portion 37 may be formed in a bent shape.

The first core material portion 26 includes a first straight portion 48, a first bent portion 36, and a first downstream side straight portion 35.

The first bending portion 36 has a substantially bent shape in a plan view.

The first downstream-side straight portion 35 extends from the first bent portion 36 in an oblique transmission direction toward one side in the width direction and has a substantially straight shape having the same width as the first straight portion 48. The downstream-side end portion of the first downstream-side straight portion 35 is continuous to the full merging path 30.

The second optical path 22 includes a second linear portion 49, a second curved portion 37, and a second downstream linear portion 44.

The second bent portion 37 has a substantially bent shape that is smaller than the first bent portion 36 in a plan view.

The second downstream-side straight portion 44 extends from the second curved portion 37 obliquely in the transmission direction toward one side in the width direction, and has a substantially straight shape having the same width as the second straight portion 49. The downstream-side end portion of the second downstream-side straight portion 44 is continuous to the full merge path 30.

In addition, the degree of bending in the first bending portion 36 is larger than the degree of bending in the second bending portion 37. Specifically, the degree of bending in the first bending portion 36 and the first downstream side straight portion 35 are greater. The angle γ1 formed is smaller than the angle γ2 formed by the second straight portion 49 and the second downstream side straight portion 44.

As shown in FIG. 10, the first optical path length L1 of the first optical path 21, the second optical path length L2 of the second optical path 22, and the third optical path length L3 of the third optical path 23 are set to the same core material 2. It is also possible to reduce the first attenuation ratio R1, the second attenuation ratio R2, and the third attenuation ratio R3 in this order by using subsequent methods and the like. Furthermore, in the core material 2 shown in FIG. 10, the first core material portion 26, the second core material portion 27, and the third core material portion 28 are connected to the total confluence portion 19 and have the same length. In the core material 2 shown in FIG. 10, when projected in the transmission direction (specifically, the direction in which the upstream end surface 5 and the downstream end surface 6 face each other), the first incident surface 11 and the second incident surface The surface 12 and the third incident surface 13 are arranged staggered with respect to the exit surface 14. For example, the first incident surface 11, the second incident surface 12, and the third incident surface 13 may be arranged on an imaginary circle having a imaginary line along the axis of the total merge path 30 as a center.

Means (1): The length of the first core material portion 26, the length of the second core material portion 27, and the length of the third core material portion 28 are shortened in this order.

Means (2): By reducing the first opening cross-sectional area OS1, the second opening cross-sectional area OS2, and the third opening cross-sectional area OS3 in this order, the first leakage ratio LR1, the second leakage ratio LR2, and the third The leakage ratio LR3 becomes smaller in this order.

Means (3): By increasing the first bending portion 36 and the second bending portion 37 in this order, or increasing the first bending portion 36, the second bending portion 37, and the third bending portion in this order, The first leakage ratio LR1, the second leakage ratio LR2, and the third leakage ratio LR3 are reduced in this order.

Means (4): The core material 2 is made to contain a 1st light absorber and a 2nd light absorber, and if necessary, it is made to contain a 3rd light absorber.

The above-mentioned means can be appropriately combined.

The above-mentioned embodiments and modifications can be appropriately combined.
The invention described above is provided as an exemplary embodiment of the invention, but it is merely an example and is not intended to be interpreted in a limited manner. Modifications of the present invention that are obvious to those skilled in the art can be included in the scope of patent application described later.
Industrial availability

Optical waveguides can be used for optical applications.

1‧‧‧ Covering material

2‧‧‧ core material

3‧‧‧ under cladding

4‧‧‧ Upper cladding material

5‧‧‧ upstream side end face

6‧‧‧ downstream end face

7‧‧‧ One of the end faces in the width direction

8‧‧‧ width end face

9‧‧‧ bevel

10‧‧‧ Optical Waveguide

11‧‧‧ the first incident surface

12‧‧‧ 2nd incident surface

13‧‧‧ 3rd incident surface

14‧‧‧ exit surface

16‧‧‧ Confluence Department

17‧‧‧Part 1 Confluence

18‧‧‧The second confluence part

19‧‧‧All Confluence Department

21‧‧‧The first optical path

22‧‧‧ 2nd optical path

23‧‧‧ 3rd optical path

25‧‧‧ Confluence Road

26‧‧‧The first core material department

27‧‧‧The second core material department

28‧‧‧ 3rd core material department

29‧‧‧ Middle Confluence Road

30‧‧‧All Confluence Road

31‧‧‧The first downstream side edge

32‧‧‧ 2nd downstream side edge

33‧‧‧ 3rd downstream edge

35‧‧‧ 1st downstream side straight section

36‧‧‧The first bend

37‧‧‧ 2nd bending part

38‧‧‧Part 1 Central Section

39‧‧‧ 1st downstream side

40‧‧‧ 2nd Central Section

41‧‧‧Second downstream section

44‧‧‧ 2nd downstream side straight section

48‧‧‧ 1st straight section

49‧‧‧ 2nd straight section

50‧‧‧ 3rd straight section

51‧‧‧Part 1

52‧‧‧Part 2

53‧‧‧3rd

55‧‧‧ Top surface

56‧‧‧ lower surface

61‧‧‧The first light-emitting part

62‧‧‧Second light emitting section

63‧‧‧ 3rd light emitting unit

65‧‧‧light-emitting device

I1‧‧‧ 1st intensity (1st light)

I2‧‧‧ 2nd intensity (2nd light)

I3‧‧‧3rd intensity (3rd light)

L1‧‧‧First optical path length

L2‧‧‧Second optical path length

L3‧‧‧3rd optical path length

LR1‧‧‧The first leak rate (first light)

LR2‧‧‧Second leak rate (second light)

LR3‧‧‧The third leak rate (3rd light)

OS1‧‧‧The first opening cross-sectional area (the first core material)

OS2‧‧‧Second opening cross-sectional area (second core material)

OS3‧‧‧3rd opening cross-sectional area (3rd core material)

R1‧‧‧1st attenuation ratio (1st light)

R2‧‧‧ 2nd attenuation ratio (2nd light)

R3‧‧‧3rd attenuation ratio (3rd light)

S1‧‧‧The first area (the first incident surface)

S2‧‧‧Second area (second incident surface)

S3‧‧‧ 3rd area (3rd incident surface)

T‧‧‧thickness

W1, W2, W3, W4, W5, W6‧‧‧Width

X, Y, Z, α1, α2, β1, β2, γ1, γ2‧‧‧ angles

FIG. 1 is a plan view showing a first embodiment of the optical waveguide of the present invention.

2A and 2B are a front view and a back view showing the optical waveguide shown in FIG. 1, and are shown: FIG. 2A is a front view seen from the upstream side of the light transmission direction, and FIG. 2B is a downstream side from the light transmission direction Seen from behind.

FIGS. 3A to 3C are plan views in which each optical path in the optical waveguide shown in FIG. 1 is highlighted, and are shown: FIG. 3A is a plan view in which the first optical path is highlighted, and FIG. 3B is a plan view in which the second optical path is highlighted. FIG. 3C is a plan view in which the third optical path is highlighted.

Fig. 4 is a plan view showing a modification of the optical waveguide shown in Fig. 1.

Fig. 5 is a plan view showing a modification of the optical waveguide shown in Fig. 1.

Fig. 6 is a plan view showing a modification of the optical waveguide shown in Fig. 1.

Fig. 7 is a plan view showing a second embodiment of the optical waveguide of the present invention.

Fig. 8 is a plan view showing a third embodiment of the optical waveguide of the present invention.

FIG. 9 is a plan view showing a modification of the optical waveguide shown in FIG. 8.

FIG. 10 is a perspective view showing a core material as a basic structure of the present invention.

Claims (10)

An optical waveguide is characterized by: Including a cladding material and a core material buried in the cladding material, The aforementioned core material has: The first incident surface is disposed on an upstream end surface in a light transmission direction, and allows light of a first wavelength to be incident on the core material; The second incident surface is disposed on the upstream end surface of the transmission direction at a distance from the first incident surface in a direction crossing the transmission direction, and supplies light of a second wavelength shorter than the first wavelength. Incident on the aforementioned core material; The third incidence surface is disposed on the upstream end surface of the transmission direction at a distance from the first incidence surface and the second incidence surface in a direction crossing the transmission direction, and is shorter than the second wavelength. Light of a third wavelength is incident on the core material; The confluence part is disposed downstream of the first incident surface, the second incident surface, and the third incident surface in the transmission direction, and supplies the light of the first wavelength, the light of the second wavelength, and the third Wavelength of light confluence; and The exit surface is disposed on the downstream side in the transmission direction of the merging portion, and emits light of the first wavelength, light of the second wavelength, and light of the third wavelength, The first area S1 of the first incident surface, the second area S2 of the second incident surface, and the third area S3 of the third incident surface are substantially the same, The first attenuation ratio R1 of the light of the first wavelength that is incident on the first incident surface and is emitted from the exit surface is greater than the light of the second wavelength that is incident on the second incident surface and is emitted from the exit surface. The second attenuation ratio R2 is larger, The second attenuation ratio R2 is larger than the third attenuation ratio R3 of the light of the third wavelength incident on the third incident surface and emitted from the exit surface. For example, the optical waveguide of claim 1, wherein the first wavelength of light includes red light, The light of the second wavelength includes green light, The light of the third wavelength includes blue light. For example, the optical waveguide of claim 1, wherein the above-mentioned confluence unit has: A first confluence part for converging any two kinds of light among the light of the first wavelength, the light of the second wavelength, and the light of the third wavelength; and The second merging portion is arranged downstream of the first merging portion in the transmission direction, and the light remaining in the remaining portion and the light merging at the first merging portion are merged. For example, the optical waveguide of claim 1, wherein the above-mentioned merging section includes a full merging section, The full confluence unit is a unit for converging three types of light of the first wavelength of light, the second wavelength of light, and the third wavelength of light. For example, the optical waveguide of claim 1, wherein the first optical path length L1 from the first incident surface to the exit surface is longer than the second optical path length L2 from the second incident surface to the exit surface, The second optical path length L2 is longer than the third optical path length L3 from the third incident surface to the outgoing surface. For example, the optical waveguide of claim 1, wherein the first leakage ratio LR1 when the light of the first wavelength is transmitted from the first incident surface to the exit surface, with respect to the light of the second wavelength is transmitted from the second incident surface to The second leakage ratio LR2 at the exit surface is large, The second leakage ratio LR2 is larger than the third leakage ratio LR3 when the light of the third wavelength is transmitted from the third incident surface to the exit surface. The optical waveguide of claim 1, wherein the aforementioned core material has: The first core material portion is disposed on the upstream side in the transmission direction of the confluence portion, and transmits the light of the first wavelength incident on the first incident surface; The second core material portion is disposed on the upstream side in the transmission direction of the confluence portion and transmits the light of the second wavelength incident on the second incident surface; and The third core material portion is disposed on the upstream side in the transmission direction of the confluence portion, and transmits light of the third wavelength incident on the third incident surface, Each of the first core material portion and the second core material portion has a shape in which an opening cross-sectional area becomes smaller as it goes toward the downstream side in the transport direction. The third core material portion has a shape in which the opening cross-sectional area becomes smaller as it goes toward the downstream side in the conveying direction, or the opening cross-sectional area is the same shape, In the first core material portion, the first opening cross-sectional area OS1 in the end edge on the downstream side of the conveying direction facing the merging portion is larger than the conveying direction of the first core material portion facing the merging portion in the second core material portion The second opening cross-sectional area OS2 in the downstream end edge is small, The second opening cross-sectional area OS2 is smaller than the third opening cross-sectional area OS3 in the end edge on the downstream side of the transport direction facing the merging portion in the third core material portion. For example, the optical waveguide according to claim 1, wherein the first incident surface and the second incident surface are both configured to project light in a direction incident on the first incident surface and the second incident surface to the exit surface. Staggered, The third incident surface is arranged so that when the light is projected in a direction incident on the third incident surface, it is the same position as the exit surface or staggered from the exit surface, The first optical path from the first incident surface to the exit surface in the core material has a first curved portion, The second optical path from the second incident surface to the exit surface in the core material has a second curved portion, The third optical path from the third incident surface to the exit surface in the core material has a straight portion or a third curved portion, The first curved portion is curved relatively to the second curved portion. The second bent portion is bent relatively larger than the third bent portion. For example, the optical waveguide of claim 1, wherein the core material contains a first light absorber and a second light absorber, so that the first attenuation ratio R1 becomes larger than the second attenuation ratio R2, and the first The attenuation ratio R2 is larger than the third attenuation ratio R3, The first light absorber is a light absorber that locally absorbs light of the first wavelength, The second light absorber is a light absorber that locally absorbs light of the second wavelength. The optical waveguide according to claim 1, wherein the light of the first wavelength is made incident on the first incident surface, and the light of the second wavelength having the same intensity as the light of the first wavelength is made incident on the second incidence When the light of the third wavelength having the same intensity as the light of the second wavelength is made incident on the third incident surface, The ratio (I1 / I2) of the first intensity I1 of the light of the first wavelength and the second intensity I2 of the light of the second wavelength emitted from the exit surface is 0.6 or more and 1.4 or less, The ratio (I1 / I3) of the first intensity I1 to the third intensity I3 of the light of the third wavelength is 0.6 or more and 1.4 or less.