JPH11184023A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a light quantity of a light source without exchanging or remarkably revising a whole optical system by connecting an incident end part of a bundle fiber to emission end parts of plural specified taper processed optical parts. SOLUTION: This device is constituted of a lamp 11 and a mirror 12, and another side end parts (emission end parts) 32 of the taper processed optical parts (taper rod) 30 are connected to respective incident end parts 21 of the bundle fiber 20. A direct beam from the lamp 11 and a reflected beam reflected by the mirror 12 are made incident on the incident end part 31 of the taper rod 30, and are made incident on the incident end parts 21 of the bundle fiber 20 from the emission end parts 32 while totally reflecting by a tapered processed side surface 33. The shape of the taper rod 30 is processed so that an area ratio of both end parts becomes n:1 when the number of branches of the bundle fiber 20 are defined (n). Thus, though the external size of the taper rod 30 becomes a conical trapezoidal shape, it may be a polygonal conic trapezoidal shape also. The extent of she taper of the tapar rod 30 is decided by considering an opening angle of a glass fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a light source device for causing light emitted from a lamp to enter a bundle fiber and to guide the light to a predetermined position.

[0002]

2. Description of the Related Art In many cases, a linear light source is used as a light source for image processing. Although a tubular light bulb has been used as the linear light source, it is difficult to reduce the size of the power supply unit, and if the size of the light emitting portion is lengthened, the operating voltage becomes higher, and the manufacturing cost of the power supply and insulation treatment increases.

Therefore, a technique using a bundle fiber in which optical fibers are bundled as a linear light source has been developed.
In this technique, light from a light source is condensed and guided to a bundle fiber, and the other end of the bundle fiber is linearly arranged to obtain a linear light source. For example, as shown in FIG.
The light emitted from the lamp 11 is reflected by the elliptical mirror 12 having the position of the lamp 11 as one focal point, and is incident on the end portion 21 of the bundle fiber placed at the position of another focal point. Tip end (other end) 22 of bundle fiber 20
In this method, the fibers are arranged in a sheet shape, and the light emitted from the tip of the fiber is condensed at a predetermined position by a cylindrical lens or the like, and the object is irradiated linearly.

[0004] Such a technique is disclosed in Japanese Utility Model Application Laid-open No. 3-16.
Japanese Patent Publication No. 101 proposes a lighting device for a line sensor camera using an optical fiber processed so that a fiber end face has an elongated shape. In this technique, the shape of the end face of the fiber is formed thicker at both end portions than at the center portion, thereby achieving uniform light intensity.

As another method, light from a light source is incident on the optical transmission rod in the axial direction, and the light is diffused by a paint or the like applied to the back surface (part of the outer peripheral surface) of the optical transmission rod. There is also a technique for obtaining a linear light source. In this technique, light incident on the rod is totally reflected at the unpainted portion of the rod outer peripheral surface and propagates in the axial direction, but is diffused by paint at the painted portion and is spread around the rod. It makes use of going out of the rod from the surface.

For example, Japanese Patent Publication No. Hei 6-38626 discloses that light from a lamp is made incident on an end face of a rod for light transmission, and fine powder having a high refractive index is axially (parallel) on the outer peripheral face of the rod. A light source unit provided with diffusion stripes attached in stripes is described. Since the diffusion fringe portion is in contact with a substance (fine powder) having a high refractive index, it is not totally reflected but refracted toward the fine powder. Since the fine powder has a high refractive index, light is easily totally reflected on the outer surface of the fine powder and returns to the inside of the rod. Of the light that has returned into the rod, the light that forms a large angle with the axial direction of the rod exits from the outer peripheral surface on the opposite side.

Japanese Patent Application Laid-Open No. 7-336502 describes a light source unit in which diffusion fringes made of fine powder having a high refractive index are similarly provided on the outer peripheral surface of an optical transmission tube. In this technique, the light amount at both ends (of the rod) is compensated for by forming the diffusion fringe portion such that the light amount at both ends is higher than that at the center in the axial direction.

[0008]

When the imaging cycle is shortened, for example, by increasing the speed of image processing, the amount of light required for imaging is insufficient. Therefore, it is necessary to increase the light amount of the light source, and generally, it is necessary to enhance the light source itself or to improve the optical system.

In the case of a method of condensing light with a mirror, it is conceivable to improve the light condensing efficiency by improving the mirror.
This requires a redesign of the mirror, which adds time and cost. In addition, the mirror is usually optimally designed in consideration of the light emission length of the lamp, the bundle fiber diameter, and the like, and it is difficult to further improve the light collection efficiency.

In a technique using a bundle fiber, such as the technique described in Japanese Utility Model Laid-Open Publication No. 3-16101, the light source itself can be enhanced, but the light source generally becomes large. In that case, it is necessary to increase the size of the bundle fiber, that is, increase the number of fibers. This also requires redesign and replacement of the bundle fiber, again increasing time and material costs.

In this case, assuming that the width of the fiber sheet at the tip is constant, the thickness of the sheet at the tip increases in proportion to the cross-sectional area of the bundle fiber, that is, the number of fibers. Therefore, it is necessary to redesign a condensing optical system such as a cylindrical lens.

JP-B-6-38626, JP-A-7-38626
In the linear light source of the type in which light enters the light transmission rod and is diffused by diffusion fringes on the outer peripheral surface of the rod as in the technique described in Japanese Patent No. 336502, it is necessary to enhance the light source itself. In this case, the size (diameter) of the end face of the rod needs to be increased in order to increase the size of the light source. When the diameter of the rod is changed, it is necessary to change the design of the cylindrical lens and the light receiving system. As a result, it is necessary to change the design and replace parts of the entire optical system including the rod.

Further, instead of directly inputting the light of the lamp to the end face of the light transmission rod, it is also possible to input the light once guided from the lamp to the bundle fiber.
Thereby, the light source itself can be installed separately from the optical transmission rod. However, also in this case, it is necessary to increase the number of bundle fibers in order to enhance the light source itself, and there is a problem such as an increase in cost as described above.

An object of the present invention is to solve the above-mentioned problems and to provide a light source device capable of increasing the light amount of a light source without replacing or significantly changing the entire optical system.

[0015]

According to the present invention, there is provided a light source device in which light emitted from a lamp is incident on a bundle fiber and guided to a predetermined position.
(B) a plurality of optical components having one end connected to each lamp and tapered toward the other end;
(C) a light source device comprising: a plurality of incident ends; and a bundle fiber connected to the other ends of the plurality of optical components. It is.

In the present invention, light from a plurality of lamps is
Light is condensed by a plurality of tapered optical components. Since the incident end of the bundle fiber is branched into a plurality (n), the cross-sectional area of each incident end is 1 / n. Therefore, each optical component is tapered so that the area of one end is equal to the cross-sectional area of the entire bundle fiber and the area of the other end is equal to the cross-sectional area of each of the branched incident ends. As a result, the light from the individual lamps is incident on the individual incident ends, so that the bundle fiber as a whole has the amount of light from the multiple lamps.

As described above, by branching the incident end of the bundle fiber, light from a plurality of lamps can be used, so that the amount of light can be increased.
Also, since it is only necessary to add lamps or spare parts equivalent to existing lamps, there is no need to replace lamps with large ones, and it is not necessary to newly design or replace lamp mounting devices and other optical systems. .

[0018]

FIG. 1 is an external view showing an example of a bundle fiber having a plurality of incident ends according to the present invention. This is an example in which the bundle fiber 20 having the cross-sectional area S is branched into two, and the cross-sectional area of the incident end portion 21 of the bundle fiber is S / 2. A tapered rod (optical component) described later is connected to the input end 21 of the bundle fiber, and an optical transmission rod is connected to the output end 22 for use.
Here, it goes without saying that the emission end portions 22 may be arranged in a sheet shape and processed.

FIG. 2 is a diagram schematically showing an example of use of the optical component 30 which has been tapered. This device uses lamp 1
1 and a mirror 12. Bundle fiber 2
0, the other end (outgoing end) 3 of the optical component (taper rod) 30 that has been tapered.
2 is connected. Direct light from lamp 11 and mirror 1
The light reflected by 2 enters the incident end 31 of the tapered rod 30, is totally reflected by the tapered side surface 33, and is incident on the incident end 21 of the bundle fiber 20 from the exit end 32.

The shape of the tapered rod 30 is such that the area ratio of both ends is n: 1, where n is the number of branches of the bundle fiber 20. As a result, the taper rod 3
0 has a truncated cone shape, but may have a truncated polygonal shape. In this example, the area ratio of both ends 31, 32 is 2: 1, and the diameter ratio in the case of a truncated cone is about 1.4:
It becomes 1.

The degree of taper of the taper rod 30 is determined in consideration of the opening angle of the glass fiber. The aperture angle 2α of the most frequently used glass fiber is 70
Degree (35 degrees with respect to the axis), and light within that angle is totally reflected on the side surface of the glass fiber and does not leak outside. Therefore, the taper angle θ of the taper rod will be examined.

FIG. 3 is a diagram showing the path of light inside and outside the tapered rod 30. Each time the light incident into the tapered rod is totally reflected by the rod side surface 33, the angle with respect to the rod axis increases (2θ). The light totally reflected by the tapered rod side surface 33 increases from the angle at the time of incidence even after exiting from the other end (outgoing surface) 32.

Since the light guided to the subsequent glass fiber is limited to light within the opening angle of the glass fiber, when the opening angle of the light emitted from the tapered rod end (outgoing surface) 32 increases, the light is guided to the glass fiber. The effective light quantity to be reduced is reduced. Therefore, the taper angle θ of the taper rod is preferably set so that the effective light amount does not become too small.
Also, it is desirable that the distance between the tapered rod end (outgoing surface) 32 and the glass fiber incident end 21 be as small as possible.

If the length of the taper rod is limited due to the dimensions of the apparatus and the taper angle θ cannot be reduced, the problem of the taper angle can be avoided by using a glass fiber having a large aperture angle. The loss of the light amount is the reflection at the entrance surface and the exit surface of the tapered rod.
%.

In the example of this embodiment, light from two lamps is guided to a two-branch fiber, but even three or more can be easily implemented by using a multi-branch fiber. Further, in this example, the cross-sectional area is reduced by the tapered rod before the light is guided to the fiber. However, the cross-sectional area may be reduced on the output side without reducing on the incident side of the bundle fiber.

[0026]

According to the present invention, since the light from a plurality of lamps can be used by branching the incident end of the bundle fiber, the amount of light can be increased. In addition, there is no need to replace the lamp with a large one, and there is an effect that it is not necessary to newly design or replace the lamp mounting device and the entire optical system.

[Brief description of the drawings]

FIG. 1 is an external view showing an example of a bundle fiber having a plurality of incident ends according to the present invention.

FIG. 2 is a diagram schematically illustrating an example of use of an optical component that has been tapered.

FIG. 3 is a diagram showing paths of light inside and outside a tapered rod.

FIG. 4 is an external view of a prior art device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Lamp 12 Mirror 20 Bundle fiber 21 Incident end of bundle fiber 22 Exit end of bundle fiber 23 Branch part of bundle fiber 30 Tapered optical component (taper rod) 31 Optical component (taper rod) entrance end 32 Optical component Exit end of (taper rod) 33 Side face of optical component (taper rod)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Matoba 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Masakazu Inomata 1-1-1, Marunouchi, Chiyoda-ku, Tokyo No. 2 Inside Nippon Kokan Co., Ltd. (72) Inventor Shoji Yoshikawa 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Tsutomu Kawamura 1-1-2 Marunouchi, Chiyoda-ku, Tokyo No. Nippon Kokan Co., Ltd. (72) Inventor Hiroyuki Sugiura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd.

Claims (1)

[Claims] 1. A light source device for causing light emitted from a lamp to enter a bundle fiber and guide the light to a predetermined position.
(A) a plurality of lamps; (b) a plurality of optical components having one end connected to each lamp and tapered toward the other end; and (c) a plurality of incident ends branched off. And a bundle fiber having these incident ends connected to the other ends of the plurality of optical components.