Patent Application
20110297817
1. Field of the Invention
The present invention relates to an L-shaped optical waveguide device manufactured in a combination of two I-shaped optical waveguides and a photoelectric conversion element.
2. Description of Related Art
A frame-shaped optical waveguide 40 shown in
However, to manufacture the frame-shaped optical waveguide 40, a mold whose area is as large as that of the frame-shaped optical waveguide 40 and a glass mask are needed. Only a peripheral part is used and a large part inside is not used in the mold and the glass mask. As the frame-shaped optical waveguide 40 gets larger, the mold and the glass mask are becoming larger. As a result, a ratio of unused portions is becoming higher. Accordingly, as the frame-shaped optical waveguide 40 becomes larger, its productivity is getting lower.
On the other hand, it is possible to use the whole area of a mold and a glass mask when manufacturing an I-shaped optical waveguide. Accordingly, the I-shaped optical waveguide has high productivity and productivity thereof is not getting lower even when the I-shaped optical waveguide becomes larger. However, it is necessary to combine a plurality of I-shaped optical waveguides with an L-shaped optical waveguide or a frame-shaped optical waveguide when being fitted around a periphery of a display screen of a touch panel.
The frame-shaped optical waveguide 40 of the conventional example 1 has low productivity. Two photoelectric conversion elements 47, 48 are needed for the L-shaped optical waveguide device 46 of the conventional example 2. Further, a gap 51 is needed between two I-shaped optical waveguides 44 and 45. Furthermore, assembly accuracy of the two I-shaped optical waveguides 44, 45 is low in X and Y directions. Assembly accuracy in the L-shaped optical waveguide device 54 of the conventional example 3 is low in a Y direction. In the L-shaped optical waveguide device 59 of the conventional example 4, the assembly accuracy is a little low in a Y direction.
It is therefore an object of the present invention to form an L-shaped optical waveguide by a combination of a plurality of I-shaped optical waveguides with high productivity.
It is another object of the present invention to keep assembly accuracy of two I-shaped optical waveguides which constitute an L-shaped optical waveguide high in X and Y directions.
It is still another object of the present invention to minimize the number of the photoelectric conversion element to one.
A device made by adding a photoelectric conversion element to an L-shaped optical waveguide is referred to as an L-shaped optical waveguide device in the present invention.
The summary of the present invention is as follows:
In a first preferred embodiment, an L-shaped optical waveguide device according to the present invention includes an L-shaped optical waveguide wherein ends of two I-shaped optical waveguides are coupled to each other approximately at a right angle, and a photoelectric conversion element optically coupled to the L-shaped optical waveguide. A coupled end of a first I-shaped optical waveguide has a concave portion and a coupled end of a second I-shaped optical waveguide has a convex portion. A concave-convex joint is formed by fitting the concave portion with the convex portion. This enables the first and second I-shaped optical waveguides to be coupled to each other. A plurality of concave-convex joints may be formed. A plurality of cores which belong to the second I-shaped optical waveguide having a convex portion respectively bend approximately at a right angle near the photoelectric conversion element to be optically coupled to the photoelectric conversion element. The terms “approximately at a right angle” mean herein 90.5.
In a second preferred embodiment of an L-shaped optical waveguide device according to the present invention, the length of a first I-shaped optical waveguide having a concave portion is longer than the length of a second I-shaped optical waveguide having a convex portion.
In a third preferred embodiment of an L-shaped optical waveguide device according to the present invention, the number of a plurality of cores which belong to a first I-shaped optical waveguide having a concave portion is greater than the number of a plurality of cores which belong to a second I-shaped optical waveguide having a convex portion.
In a fourth preferred embodiment of an L-shaped optical waveguide device according to the present invention, a light-emitting surface of a first I-shaped optical waveguide having a concave portion and a light-emitting surface of a second I-shaped optical waveguide having a convex portion are disposed on a substantially identical surface. The terms “disposed on a substantially identical surface” mean herein that when a plurality of cores of the first I-shaped optical waveguide having a concave portion and a plurality of cores of the second I-shaped optical waveguide having a convex portion are optically coupled to one photoelectric conversion element, there is practically no difference between respective optical coupling efficiency.
In a fifth preferred embodiment of an L-shaped optical waveguide device according to the present invention, a plurality of cores of a first I-shaped optical waveguide having a concave portion and a plurality of cores of a second I-shaped optical waveguide having a convex portion are optically coupled to one photoelectric conversion element.
In a sixth preferred embodiment of an L-shaped optical waveguide device according to the present invention, a coupling by a convex-concave joint is fixed by an ultraviolet curable adhesive.
It is possible to obtain the following advantages according to the present invention:
(1) It is possible to improve productivity of an L-shaped optical waveguide by the formation of the L-shaped optical waveguide by a combination of a plurality of I-shaped optical waveguides with high productivity.
(2) It is possible to keep assembly accuracy of two I-shaped optical waveguides which constitute an L-shaped optical waveguide high in X and Y direction.
(3) Only one photoelectric conversion element is needed.
According to the present invention, it is possible to assemble an L-shaped optical waveguide device so as to be substantially orthogonal to the two I-shaped optical waveguides by fitting a concave portion of a first I-shaped optical waveguide with a convex portion of a second I-shaped optical waveguide. Further, it is possible to minimize the number of the photoelectric conversion element to one by bending a plurality of cores of the second I-shaped optical waveguide having a convex portion at a right angle near the photoelectric conversion element.
For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings.
The preferred embodiments of the present invention will now be described with reference to
As shown in
As shown in
As shown in
The phrase “bend approximately at a right angle near the photoelectric conversion element 14” has a meaning below. The cores 18 disposed at a place distant from the photoelectric conversion element 14 are nearly parallel to a long side of the I-shaped optical waveguide 12 having the convex portion 16. However, the cores 18 are nearly perpendicular to the long side of the I-shaped optical waveguide 12 having the convex portion 16 near the photoelectric conversion element 14. That is to allow light passing through the cores 18 to vertically enter the photoelectric conversion element 14 that comes in contact with the long side of the I-shaped optical waveguide 12 having the convex portion 16. In addition, the terms “nearly parallel” mean herein that a distortion from a true parallelism is within 5. And the terms “nearly perpendicular” mean herein that a distortion from a true perpendicularity is within 5.
As shown in
A plurality of concave-convex joints 17 may be provided in the L-shaped optical waveguide 13. Although the concave portion 15 and the convex portion 16 shown in
Such coupling makes it possible to keep assembly accuracy of the two I-shaped optical waveguides 11, 12 high in X and Y directions, which leads to form the high-precision L-shaped optical waveguide 13.
As shown in
The cores 18, 19 shown in
The cross-sectional shape of respective cores 18a, 19a is not particularly limited, but is preferably trapezoidal or rectangular. Respective cores 18a, 19a preferably have a width t2 of 10 m to 500 m. Respective cores 18a, 19a preferably have a height t3 of 10 m to 100 m.
The cladding layer 20 is formed of any material having a lower refractive index than that of the cores 18a, 19a. It is possible to adjust the refractive index of a resin in the material forming the cores 18a, 19a and the cladding layer 20 to be higher or lower in accordance with the kind of organic groups introduced in the resin or a content of the organic groups in the resin. Examples of the material for forming the cores 18a, 19a and the cladding-layer 20 include materials listed in Examples in JP 2010-32661 A.
The cores 18 that belong to the I-shaped optical waveguide 12 having the convex portion 16 respectively bend approximately at a right angle near the photoelectric conversion element 14 to be optically coupled to the photoelectric conversion element 14. The cores 19 that belong to the I-shaped optical waveguide 11 having the concave portion 15 linearly extend (may bend in the middle) to the photoelectric conversion element 14 to be optically coupled to the photoelectric conversion element 14.
As shown in
In the L-shaped optical waveguide device 10 of the present invention, the length L1 of the I-shaped optical waveguide 11 having the concave portion 15 is preferably longer than the length L2 of the I-shaped optical waveguide 12 having the convex portion 16. The difference (L1 L2) between the length L1 of the I-shaped optical waveguide 11 having the concave portion 15 and the length L2 of the I-shaped optical waveguide 12 having the convex portion 16 is set appropriately according to the purpose, but is preferably 20 mm to 200 mm.
In the L-shaped optical waveguide device 10 of the present invention, the number of the cores 19a that belong to the I-shaped optical waveguide 11 having the concave portion 15 is preferably greater than the number of the cores 18a that belong to the I-shaped optical waveguide 12 having the convex portion 16. The number of the cores 19a that belong to the I-shaped optical waveguide 11 having the concave portion 15 is preferably 40 to 700. The number of the cores 18a that belong to the I-shaped optical waveguide 12 having the convex portion 16 is preferably 30 to 500.
According to the present invention, the L-shaped optical waveguide 13 with smaller widths W1 and W2 than those of conventional ones may be obtained. In the case of the L-shaped optical waveguide 13 having an opposite angle of 10.4 inches (horizontal to vertical ratio: 4:3), the widths W1 and W2 are as below.
As shown in
As shown in
Accordingly, it is possible to reduce the maximum width (W1 or W2) of the L-shaped optical waveguide 13 by making the length L1 of the I-shaped optical waveguide 11 having the concave portion 15 longer than the length L2 of the I-shaped optical waveguide 12 having the convex portion 16.
A width W3 of the convex portion 16 of the concave-convex joint 17 in the L-shaped optical waveguide 13 to be used in the present invention shown in
The photoelectric conversion element 14 to be used in the present invention is optically coupled to the cores 18, 19 of the L-shaped optical waveguide 13 to convert optical signals into electrical signals. Examples of the photoelectric conversion element 14 typically include a CMOS linear image sensors and CCD linear image sensors. Such a photoelectric conversion element 14 has a plurality of phtodiodes (light-receiving sections) linearly arranged.
At the time of optical coupling, the position of the photoelectric conversion element 14 is adjusted so that an output electrical signal may be maximized when light traveling through the cores 18, 19 of respective I-shaped optical waveguides 11, 12 enters the photoelectric conversion element 14. Subsequently, the photoelectric conversion element 14 is fixed to respective I-shaped optical waveguides 11, 12 by an ultraviolet curable adhesive.
A plurality of cores 18 formed of an epoxy-based resin including a fluorene skeleton were formed on a surface of an under-cladding layer made of an epoxy-based resin including an alicyclic skeleton by an exposure development method. The under-cladding layer has a thickness of 20 m and a refractive index of 1.51. Cores 18a respectively have a height t3 of 50 m, a width t2 of 15 m, and a refractive index of 1.59. The number of cores 18a is 62.
An over-cladding layer wherein the cores 18 were embedded was formed on a surface of the under-cladding layer. The over-cladding layer has a thickness of 1 mm and the material thereof is the same as that of the under-cladding layer.
In this way, an I-shaped optical waveguide 12 having a convex portion 16 was formed. The dimensions of the I-shaped optical waveguide 12 were W2=15 mm, L2=172 mm, and t1=1,020 m.
Similarly, a plurality of cores 19 were formed on a surface of an under-cladding layer and an over-cladding layer wherein the cores 19 were embedded was formed to form an I-shaped optical waveguide 11 having a concave portion 15. Cores 19a respectively have a height t3 of 50 m and a width t2 of 15 m. The number of cores 19a is 82. The dimensions of the I-shaped optical waveguide 11 are W1=13 mm, L1=234 mm, t1=1,020 m.
The I-shaped optical waveguide 12 having the convex portion 16 was coupled to the I-shaped optical waveguide 11 having the concave portion 15 so as to form a concave-convex joint 17 by fitting the convex portion 16 with the concave portion 15 and then fix the I-shaped optical waveguide 12 having the convex portion 16 and the I-shaped optical waveguide 11 having the concave portion 15 by an ultraviolet curable adhesive. As a result, an L-shaped optical waveguide 13 was formed.
A light-emitting surface 22 of the I-shaped optical waveguide 12 having the convex portion 16 is disposed on a substantially identical surface of a light-emitting surface 21 of the I-shaped optical waveguide 11 having the concave portion 15. The light-emitting surface 22 of the I-shaped optical waveguide 12 having the convex portion 16 and the light-emitting surface 21 of the I-shaped optical waveguide 11 having the concave portion 15 were optically coupled to a photoelectric conversion element 14 (manufactured by Hamamatsu Photonics K.K., product name: CMOS linear image sensor) and fixed via an ultraviolet curable adhesive. As a result, an L-shaped optical waveguide device 10 was manufactured.
The thus manufactured L-shaped optical waveguide device 10 is capable of:
Applications of the L-shaped optical waveguide device 10 of the present invention are not particularly limited, but the L-shaped optical waveguide device 10 is preferably used for an optical touch panel 30 shown in
Optical groups emitted from the photoelectric conversion element 32 pass through a plurality of cores 34, of a light-emitting-sided L-shaped optical waveguide 33 and then emit to a coordinate input region 36. The optical groups having passed through the coordinate input region 36 enter the light-receiving-sided L-shaped optical waveguide 13 and then pass through the cores 18, 19 of the L-shaped optical waveguide 13 to enter the photoelectric conversion element 14. Since the optical groups in the coordinate input region 36 are partially blocked by a finger or a pen, the optical groups to enter the photoelectric conversion element 14 partially disappear, the position coordinate of the finger or the pen is detected.
This application claims priority from Japanese Patent Application No. 2010-127712, which is incorporated herein by reference.
There has thus been shown and described a novel L-shaped optical waveguide device which fulfills all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-127712 | Jun 2010 | JP | national |
