JPH06148442A - Linear light guide - Google Patents

Abstract

PURPOSE:To realize linear illumination where a light quantity spot is small and there is no directivity of light similar to a fluorescent lamp and which has much higher brightness than the fluorescent lamp by efficiently guiding the exiting light to a light diffusing board by means of a hollow body whose inside surface is a reflecting surface and also eliminating the directivity of the exiting light by means of the diffusing board. CONSTITUTION:As to the linear light guide obtained by circularly focusing one end of an optical fiber bundle to be a light incident end 1a, and linearly aligning the other end to be a light exiting end 1b; the light diffusing board 3 is arranged with a certain interval from the light exiting end 1b, and the hollow body 2 whose incident port is opposed to the light exiting end 1b, whose exiting port is opposed to the light diffusing board 3 and which has a reflecting surface on an inside surface 2c is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear light guide used as an illuminating device required for image processing and the like.

[0002]

2. Description of the Related Art Conventionally, as a line illumination device, a high frequency lighting fluorescent lamp and a line light guide using a plurality of optical fibers have been used. In the conventional optical fiber linear light guide, one end of the optical fiber bundle is formed as a circular focusing end, and the other is configured as a linear array end. And by coupling the light source to the circular focusing end,
Linear illumination is possible from the linear array end. By using, for example, a halogen lamp as a light source, extremely high-intensity line-shaped illumination is realized as compared with a fluorescent lamp.

[0003]

When a conventional linear light guide is used to illuminate a light diffusing object and the image is picked up by a camera, a very great effect can be obtained.
When illuminating an object having a small light diffusivity and capturing an image with a camera, there are the following two disadvantages. First, since the light emitted from the optical fiber has directivity, the amount of light from a direction with a deep angle is extremely reduced, and secondly, the distance between the object and the linear light guide is reduced. Then, since the light emitting end approaches the focal position of the camera, the light amount unevenness of each optical fiber affects the imaging waveform of the camera.

The present invention has been made on the basis of the above background. An object of the present invention is to take advantage of the high brightness of an optical fiber linear light guide and to achieve a high level of light quantity from a deep angle direction. It can be maintained at the same time, and even if the distance between the object and the linear light guide is reduced,
An object of the present invention is to provide a linear light guide in which the light amount unevenness of each optical fiber does not affect the image pickup waveform of the camera.

[0005]

The above-mentioned problems can be solved by the present invention. That is, the line-shaped light guide of the present invention is a line-shaped light guide in which one end of an optical fiber bundle is focused into a circle to form a light incident end, and the other end is aligned in a line to form a light emitting end. A light diffusing plate is arranged at a distance from the light emitting end, and a hollow body is provided which has an entrance opening facing the light exiting end, an exit opening facing the light diffusing plate, and an inner surface having a reflecting surface. It is a thing.

[0006]

According to the invention having the above structure, the emitted light is efficiently guided to the light diffusing plate by the hollow body having the inner surface as the reflecting surface, and the directivity of the emitted light is eliminated by the diffusing plate. Therefore, as with a fluorescent lamp, it has a characteristic that the unevenness of the light amount is small and there is no directivity, and it becomes possible to perform line illumination with a very high brightness as compared with the fluorescent lamp.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A linear light guide according to an embodiment of the present invention will be specifically described with reference to FIG. In the optical fiber linear light guide 1 shown in FIG. 1 which is a plan view of a partial cross section showing the cross section of the hollow body, one end of the optical fiber bundle is a circular focusing end 1a.
And the other end is configured as a linear array end 1b, and a light source (not shown) is optically connected to the circular focusing end 1a.

FIG. 2 shows a side view of a partial cross section of this example. In the linear light guide according to this embodiment, the light diffusing plate 3 is located at a position at a front distance D from the linear array end (1b) and the linear array end 1b is shown in FIG. 3 which is a longitudinal sectional view of the hollow body. A hollow body 2 composed of four light reflection plates 2a and 2b surrounding the space up to the light diffusion plate 3 from four directions is arranged. Here, the inner surfaces 2c of the light reflection plates 2a and 2b
Has a reflective mirror structure such as a mirror surface treatment or a reflective tape. The light emitted from the linear array end 1b is
The light is emitted with a certain spread angle, but the spread in the longitudinal direction of the linear light guide is restricted by the light reflecting plate 2a, and the spread in the thickness direction is restricted by the light reflecting plate 2b. Since the inner surfaces of the light reflection plates 2a and 2b have a reflection mirror structure, most of the emitted light can reach the light diffusion plate 3 by multiple reflection. Finally, the light diffusing plate 3 diffuses the light, and the light amount unevenness of each optical fiber and the directivity of the emitted light can be erased.

Here, the distance W between the light reflection plates 2b is selected according to the required width of the linear illumination, but the smaller W is, the higher the density of the light reaching the light diffusion plate 3 is, and the higher the brightness is. To do. In addition, the linear array end 1b and the light diffusion plate 3
As for the distance D up to, the greater the D, the greater the light diffusion effect, but the diameter of the optical fiber used is 0.5 mm.
In this case, if D is set to 20 mm or more, a sufficient diffusion effect can be obtained. The present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above-mentioned embodiment, the hollow body is formed by four reflecting plates, but as shown in the vertical sectional view of FIG. 3, the hollow body 2 having the inner surface 2c having the reflecting surface can be used.

[0010]

As described above, according to the present invention, since the emitted light can be efficiently guided to the light diffusing plate by the hollow body having the inner surface as the reflecting surface, and the directivity of the emitted light can be eliminated by the diffusing plate. As with a fluorescent lamp, it has a feature that the unevenness of the light amount is small and there is no directivity, and it becomes possible to perform line illumination with a very high brightness as compared with the fluorescent lamp. Therefore, it is possible to perform line-shaped illumination with a small amount of light and a small directivity while keeping the advantage of high brightness.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional plan view of a linear light guide according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional side view of a linear light guide according to an embodiment of the present invention.

FIG. 3 is a vertical sectional side view of a hollow body according to an embodiment of the present invention.

FIG. 4 is a vertical sectional side view of a hollow body according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical fiber bundle 1a ... Circular focusing end 1b ... Linear array end 2 ... Hollow body 2a ... Light reflection plate (longitudinal direction) 2b ... Light reflection plate (thickness Direction) 2c ... inner surface 3 ... light diffusing plate

Claims (1)

[Claims] 1. A linear light guide in which one end of an optical fiber bundle is focused into a circle to form a light incident end and the other end is aligned in a line to form a light emitting end, with a space from the light emitting end. A line-shaped light guide, wherein a light diffusion plate is disposed, and a hollow body is provided, in which an entrance is opposed to a light exit end, an exit is opposed to the light diffuser, and an inner surface has a reflection surface.