JPH05203822A - End face treatment of optical fiber - Google Patents

Abstract

PURPOSE:To facilitate the operation for microlenses by applying a photosensitive resin on the end faces of optical fibers, exposing and developing this photosensitive resin so as to have an intensity distribution and further, subjecting the resin to full-surface exposing. CONSTITUTION:Only the photosensitive resin 13 on the front surface parts of core parts 11 are exposed to have the intensity distribution when the photosensitive resin 13 is applied on the end face of an optical fiber bundle 20 and is irradiated with light for exposing from below the optical fiber bundle 20. Curing begins partially and cured parts 14 are formed. The photosensitive resin is thereafter developed by using trichloroethylene as a developer, by which the uncured parts 13a not subjected to the exposing are removed. However, the uncured parts 13a around the cured parts 14 remain without being completely removed and, therefore, these parts are developed to the lens shape having gentle and continuous curves. The resin is thereafter exposed from above the uncured parts 13a, by which the uncured parts 13a are completely cured and a lens array 15 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating an end surface of an optical fiber, and more particularly to a method for treating an end surface of an optical fiber used in a display device or the like in which an image output end is an optical fiber bundle.

[0002]

In recent years, optical fibers have begun to be used to transmit images on display devices. However, in such a display device, there is a viewing angle limited by the numerical aperture of the optical fiber used, and an image cannot be sufficiently viewed at an angle exceeding this. As a method of enlarging this viewing angle, a method of processing the end face of the optical fiber into a curved surface (Japanese Patent Laid-Open No. 60-169).
No. 833) has been proposed. Further, although the direct purpose is to optically couple the image forming apparatus and the optical fiber, there is also a proposal of a lens group (microlens array) that matches the arrangement of the optical fibers (JP-A-1-189616), and the combination of the optical fiber and the lens. Is an indispensable configuration in the display device.

[0003]

In the above method of combining an optical fiber and a microlens array, it is important to align the optical fiber and the microlens array, and it is applicable when the optical fibers are regularly arranged. However, there is a problem that it is difficult to apply when the optical fibers are arranged irregularly.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an end face processing method for an optical fiber which can be applied even when the optical fibers are arranged irregularly.

[0005]

In order to achieve the above object, the method of treating the end face of an optical fiber according to the present invention comprises applying a photosensitive resin on the end face of the optical fiber, and then applying strength to the photosensitive resin through the optical fiber. It is characterized in that a minute lens is formed on the end face of the optical fiber by exposing with a distribution, then developing and further exposing the whole surface.

[0006]

According to the above method, a photosensitive resin is applied on the end face of an optical fiber, and then exposed through the optical fiber. The core portion of the optical fiber allows light to pass through while the cladding portion does not. Therefore, the photosensitive resin is exposed with an intensity distribution. From this, the shape of the core portion is directly reflected on the exposed portion. The photosensitive resin is cured by being exposed to light, and the unexposed portion remains uncured, but since the boundary between the cured portion and the uncured portion is not clear,
When development is performed in the next step, the uncured portion around the cured portion is not completely removed and remains. Therefore, it is developed into a lens shape having a smooth continuous curved surface. After that, the entire surface is exposed from the side opposite to the above-mentioned exposure, whereby the uncured portion is completely cured, and a minute lens is formed on the end face of the optical fiber.

As a result, the end face of the optical fiber and the microlens are always integrated, and it becomes unnecessary to consider the arrangement of the optical fibers.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an optical fiber end face processing method according to the present invention will be described below with reference to the drawings. 1 (a)-
(E) is sectional drawing which showed each process for demonstrating the end surface processing method of the optical fiber which concerns on a present Example. Each optical fiber 16 comprises a core portion 11 and a clad portion 12, and a large number of these optical fibers 16 are gathered together to form an optical fiber bundle 20. A photosensitive resin (for example, a photodimerization type resin mainly containing polyvinyl cinnamate, etc.) 13 is applied to the end surface of the optical fiber bundle 20 (FIG. 1A). Next, when light for exposure is irradiated from below the optical fiber bundle 20 (FIG. 1B), the light passing through the core portion 11 causes the photosensitive resin 13 on the upper surface portion of the core portion 11 to be irradiated.
Only the part is exposed with an intensity distribution, and partial curing starts to form a cured part 14. On the other hand, since the cladding 12 does not transmit light, the photosensitive resin 13 on the upper surface of the cladding 12 is not exposed and remains uncured (FIG. 1).
(C)). Then, using trichlene as a developing solution, development is performed to obtain an uncured portion 1 that has not been exposed.
Remove 3a. However, the cured portion 14 and the uncured portion 1
Since the boundary with 3a is not clear, the uncured portion 13a around the hardened portion 14 remains without being removed. Therefore, it is developed into a lens shape having a smooth continuous curve (FIG. 1D). Next, the uncured part 1
3a is exposed to completely cure the uncured portion 13a to form the lens array 15 (FIG. 1).
(E)).

FIG. 2 is a graph showing the relationship between the degree of curing and the light irradiation amount of the photosensitive resin 13 used in this example. From FIG. 2, it can be seen that the curing proceeds rapidly at a certain light irradiation amount. Therefore, the difference between the hardened portion 14 and the uncured portion 13a is easily apparent, and it can be said that this is suitable for forming a lens shape.

By the steps shown in FIGS. 1 (a) to 1 (e),
A lens array 15 having a continuous curved surface can be formed on the end surface of the optical fiber bundle 20. In this case, since the end face of the optical fiber bundle 20 and the lens array 15 are integrated, it can be easily applied to the irregularly arranged optical fiber bundle 20.

[0011]

As described above in detail, in the optical fiber end face treatment method according to the present invention, a photosensitive resin is applied on the end face of the optical fiber, and then the photosensitive resin has a strength distribution through the optical fiber. The microlenses are formed on the end faces of the optical fibers by exposing, exposing, then developing, and then exposing the entire surface. Therefore, it can be applied to an optical fiber bundle having an irregular arrangement. That is, it is possible to easily and accurately manufacture a minute lens corresponding to each optical fiber. It is also easy to cut the cured resin portion and obtain the end face of the original optical fiber again.

[Brief description of drawings]

1 (a) to 1 (e) are schematic cross-sectional views sequentially showing each step in the embodiment of the optical fiber end face processing method according to the present invention.

FIG. 2 is a graph showing the relationship between the curing degree and the light irradiation amount of the photosensitive resin used in the examples.

[Explanation of symbols]

 13 Photosensitive resin 16 Optical fiber

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Keiji Sakai 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Keio Yoshida 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka (72) Inventor Takahiro Miyake 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Prefecture

Claims (1)

[Claims] 1. The optical fiber is obtained by applying a photosensitive resin on the end face of an optical fiber, exposing the photosensitive resin through the optical fiber with a strength distribution, and then developing and further exposing the entire surface. A method for treating an end face of an optical fiber, which comprises forming a minute lens on the end face of the optical fiber.