JP3032494B2 - Light guide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide capable of transmitting light from a light source and irradiating light at a suitable incident angle to a surface to be irradiated.

[0002]

2. Description of the Related Art Conventionally, when a surface inspection of various industrial products is performed using an imaging device using a CCD or the like, for example,
To ensure the brightness of the imaging area to be inspected, Fig.
3 (a), light guide 8 as exemplified in FIG.
0 was used.

The light guide 80 transmits light from a light source incident on a light receiving portion 82 to a ring-shaped support 86 side through a plurality of optical fibers 84, and transmits the transmitted light to the ring-shaped support 86. The light is emitted from the emission end 84a of the optical fiber 84 exposed at one end face 86a of the 86. Emission ends 84a of the plurality of optical fibers 84
Are arranged at equal intervals along the circumference of the ring-shaped support member 86, and light emitted from each emission end 84a is, as shown by a dotted line in FIG. It spreads out in a conical shape as indicated by arrows at both ends. In this state, for example, when the surface to be illuminated is located at a position indicated by D1 in FIG. 4 , light is irradiated over the entire range of P1 to P2 shown in FIG. If the surface to be illuminated is imaged through the interface, a surface inspection or the like can be performed without any problem.

[0004]

By the way, there are cases where the eyepiece side of the imaging device must be brought close to the product surface due to various factors such as the structure of the imaging device and the size of the inspection target area. Also, the distance between the light guide 80 and the irradiated surface may not be sufficiently long.

However, for example, in FIG. 4 , when the irradiated surface approaches the light guide 80 up to the position indicated by D2, the range of Q1 to Q2 and Q3 to Q4 shown in FIG. , Q2 to Q3, since light is no longer irradiated, there is a problem that a dark portion is formed in the captured image when the surface to be irradiated is imaged through the center hole of the ring-shaped support 86. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a light guide capable of irradiating light over the entire necessary range even when the distance to the surface to be irradiated is very short. To provide.

[0007]

In order to achieve the above object, a light guide according to the present invention can transmit light from a light source to an output end from an input end. A plurality of optical fibers, and a support for fixing each emission end of the plurality of optical fibers in a predetermined arrangement state, for an irradiated surface at a predetermined relative position with respect to the support, In a light guide capable of irradiating light emitted from an emission end of the optical fiber , the plurality of optical fibers
Is the position surrounding the axis perpendicular to the plane to be irradiated
Each of the exit ends is disposed and the optical axis of each of the exit ends is the axis line.
At an installation angle such that the
Fixed to the support, and the output end is attached.
There are two or more different mounting angles,
The optical axes of the emission ends with different mounting angles are separated from the support.
At different positions intersects the axis,
Simultaneously irradiate light from emission ends with different mounting angles
It is characterized by having such a configuration .

In this light guide, a plurality of optical fiber
Iva surrounds an axis perpendicular to the plane to be irradiated
Each output end is arranged at a position, and the optical axis of each output end is
Mounting angle such that it is located at the intersection with the axis
In the above, it is fixed to the support, and at the same time,
There are two or more different mounting angles.
The optical axes of the emission ends with different mounting angles are
Intersects the axis at different distances from the carrier
From the emission ends with different mounting angles at the same time.
It is configured to emit light . So a certain corner
When the light is emitted from the emission end arranged at an angle, the dark portion generated on the surface to be irradiated can be irradiated with the light emitted from the emission end arranged at another angle. Light can be irradiated over the entire required area on the surface.

In particular, when the distance from the emission end of the optical fiber to the surface to be irradiated is short, the range in which light can be irradiated at one emission end is narrowed and the dark portion is easily enlarged, so that the optical fibers are arranged at the same angle. While it is difficult to eliminate the dark part, the light guide of the present invention can easily dissolve the dark part on the illuminated surface because the optical fibers may be arranged at various angles in consideration of the elimination of the dark part. can do.
Further, according to the light guide of the present invention, the ring-shaped support
From the output end of the optical fiber
Light is emitted in a direction that intersects the axis that coincides with the center of the support
Can be observed through the center hole of the ring-shaped support.
Light is radiated from the entire circumference to the capable irradiation surface. did
Therefore, a cylindrical lens is provided in the hole of the ring-shaped support.
If you place a CCD camera and various filters,
Is the equivalent distance from the center of the lens or filter
The lens and filter.
Without strictly considering the arrangement angle of the ring-shaped support
In addition, uniform illumination can be easily provided.

The end face of the optical fiber on the side of the emission end may be a plane perpendicular to the axial direction of the optical fiber. If spherical processing is performed on the end face on the emission end side, the radiation angle of light at the emission end of the optical fiber becomes large. Therefore, it is preferable to irradiate light over a wider range.

In processing the spherical surface of the end of the optical fiber,
Various processing methods that are already generally known can be used. As a specific example, for example, a method in which the end surface of a glass-based or plastic-based optical fiber is polished while being pressed against an abrasive having a concave-shaped polishing surface to form a spherical surface, a plastic-based optical fiber A method in which the end face is brought into pressure contact with a concave heater and melted by heat to form a spherical shape may be used.

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

Next, an embodiment of the present invention will be described with reference to an example. As shown in FIGS. 1A to 1C, a light guide 1 includes a light receiving unit 1 connected to a light source.
0, a plurality of optical fibers 12 for transmitting the light incident on the light receiving unit 10, and a ring-shaped support 14 for fixing the emission ends 12a of the optical fibers 12 in an annularly arranged state. For convenience of illustration, the optical fiber 12 is depicted as being exposed to the outside, but is actually entirely covered by a protective tube 16.

The ring-shaped support 14 is an annular ring having an inner diameter of 62 mm, an outer diameter of 85 mm, and a thickness of 20 mm, and has a passage for passing the optical fiber 12 therein. The optical fiber 12 is a plastic optical fiber having a diameter of 0.5 mm,
The output end 12a of the optical fiber 12 is
Are arranged at regular intervals of 10 degrees (approximately 1.5 mm intervals) along the circumference of the light emitting end, and the mounting angles of these emission ends 12a are alternately changed. As shown in FIG. 1B, one of the mounting angles is an angle α (in the present embodiment, α) with respect to the center axis direction of the ring-shaped support 14.
= 60 degrees), and the other forms an angle β (β = 45 degrees in the present embodiment) with respect to the center axis direction of the ring-shaped support 14 as shown in FIG. 1C. Further, the end surface of the optical fiber 12 on the side of the emission end 12a is subjected to spherical processing, whereby the emission angle of light from the emission end 12a is about 1
00 degrees and simply cut optical fiber (radiation angle about 60
The radiation angle is much larger than (degree).

According to the light guide 1 configured as described above, the light emitted from the emission end 12a of the optical fiber 12 has each emission end 12a as a vertex as shown by a dotted line in FIG. Spreads in a cone as shown by the arrow. As described above, the emission ends 12a are alternately attached at different angles, so that the light emitted from the emission ends 12a having different attachment angles irradiates the mutually irradiable ranges, and as a result, the illuminated surface Is located at a relatively distant position D1, and even when the illuminated surface is at a relatively close position D2, an unirradiable area does not occur on the illuminated surface. Therefore, for example, if the illuminated surface is imaged by the imaging device through the center hole of the ring-shaped support body 14, a clear image without any adverse effect due to the dark portion can be obtained, and the surface inspection or the like is favorably performed. be able to.

Although the embodiments of the present invention have been described above, various specific embodiments other than those described above are conceivable for the embodiments of the present invention .

[0022]

[0023]

[Brief description of the drawings]

FIG. 1 shows a light guide as an embodiment;
(A) is a front view of a state in which a part thereof is cut away to expose an internal structure, (b) is an end view of a cut plane taken along line AA, and (c) is an end view of a cut plane taken along line BB. is there.

FIG. 2 is an explanatory diagram illustrating a light emission state by a light guide as an embodiment.

3A and 3B show a conventional light guide, and FIG. 3A is a front view showing a state in which a part of the light guide is broken to expose an internal structure;
(B) is an end view of the XX line cut surface.

FIG. 4 is an explanatory view showing a state of light emission by a conventional light guide.

[Description of Signs] 1 ... light guide, 10 ... light receiving section, 12 ...
Optical fiber, 12a: emitting end, 14: ring-shaped support, 16: protective tube .

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fuyuhiko Yoshikura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (72) Inventor Kazuo Funakubo 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric (72) Inventor Shoji Ichihashi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (56) References JP-A-10-132752 (JP, A) JP-A-6-60802 (JP) , U) Japanese Utility Model Showa 61-42711 (JP, U) Japanese Utility Model Showa 62-4011 (JP, U) Japanese Utility Model 4-3292 (JP, Y2) Japanese Utility Model 4-12481 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 6/00 331 F21V 8/00 G02B 6/04

Claims (2)

(57) [Claims] 1. An optical fiber comprising: a plurality of optical fibers capable of transmitting light from a light source from an incident end to an output end; and a support for fixing the respective output ends of the plurality of optical fibers in a predetermined arrangement state, In a light guide capable of irradiating light radiated from an emission end of the optical fiber to a surface to be illuminated at a predetermined relative position with respect to the support, the plurality of optical fibers are planes to be illuminated. Orthogonal to
Each output end is arranged at a position surrounding the axis
So that the optical axis of the launch end is located at a position crossing the axis
Fixed to the support at a suitable mounting angle, and two or more different
With different mounting angles
The optical axis at the end is located at a position at a different distance from the support.
Intersects the said axis Te, simultaneously irradiated with light from different emission end of the mounting angle
Light guide characterized by being comprised as follows . 2. The light guide according to claim 1, wherein a spherical surface is applied to an end face of the optical fiber on an emission end side.