JPH10186146A - Light guide holding mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide holding mechanism holding a pillar shaped light guide in a state in which it is floated in air so that an optical transmission loss becomes small as much as possible. SOLUTION: A pillar shaped light guide 12 is housed in a cylindrical hollow lens barrel 20 and is putted into opening holes of positioning members 60 arranged in the vicinities of both ends of the lens barrel 20. At this time, the light guide 12 is held in the radial direction of the lens barrel by performing energization from counter positions with energizing members 70 so that the light guide 12 is brought into line contacts with top end parts of the members 70.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide holding mechanism, and more particularly, to holding a columnar light guide.

[0002]

2. Description of the Related Art Conventionally, as a light guide or light transmitting element, for example, as shown in a perspective view of FIG. 1, a columnar light guide 1 which emits light 2a from one end face 1a and emits light 2b from the other end face 1b is used. Are used for various purposes. As shown in the cross-sectional view of FIG. 2, such a columnar light guide 1 is used for illumination because the emitted light 2b having a substantially uniform luminance distribution is obtained by reflection inside the light guide 1. There are cases.

When the columnar light guide 1 is used for illumination as described above, in order to reduce light transmission loss, a silver vapor-deposited surface is formed on the outer peripheral surface 1c of the columnar optical component 1 to prevent emission from the outer peripheral surface 1c. May be. But with this method,
Since light transmission loss occurs on the reflecting surface 1c during internal reflection,
Light cannot be transmitted with high efficiency.

As an optical member capable of transmitting light with high efficiency, an optical fiber having a two-layer structure having different densities is generally known. The optical fiber has an advantage that it can be freely bent, but has disadvantages such that the entrance and exit surfaces are very small due to its small size, and there is a method of using it in a bundle, but it is expensive.

On the other hand, if the columnar light guide 1 is held in the air, it is possible to transmit light efficiently by causing total reflection due to a density difference in the light guide 1 like an optical fiber.

However, in order to hold the light guide 1, it is necessary to make contact with the light guide 1, and since the contact portion does not undergo total reflection, it causes light transmission loss.

[0007]

SUMMARY OF THE INVENTION Accordingly, the technical problem to be solved by the present invention is to provide a light guide holding mechanism for holding a columnar light guide in a floating state in the air so that light transmission loss is reduced as much as possible. It is to be.

[0008]

SUMMARY OF THE INVENTION The present invention provides a light guide holding mechanism having the following configuration to solve the above technical problems.

The light guide holding mechanism includes a cylindrical lens barrel, a columnar light guide housed in the lens barrel along an axis, and at least two axial directions in the lens barrel. At least two line contact members supporting the columnar optical member in line contact with a part of the entire circumference of the surface in the circumferential direction; And at least two biasing members that are arranged at least at two locations in the axial direction, make point or line contact with the outer peripheral surface of the light guide, and bias the light guide toward the line contact member. The light guide is sandwiched between the urging member and the line contact member.

In the above structure, the light guide is sandwiched between the urging member and the line contact member in a direction perpendicular to the axis. Since the light guide is thus sandwiched at at least two places in the axial direction, it is supported without tilting. Since the contact portion between the light guide and the urging member and the line contact member is a point or a line, light transmission loss is extremely small due to the contact portion.

Therefore, the light guide holding mechanism can hold the columnar light guide in a state of being floated in the air so as to minimize the light transmission loss.

Preferably, the urging member comprises a spring member. The lens barrel further includes a presser screw member attached to the urging member so as to be movable in the radial direction. The urging member is pressed against the columnar optical member by the holding screw member to elastically urge the optical member toward the line contact member.

In the above configuration, the pressing force of the urging member pressing the light guide against the line contact member is within a range in which the light guide can be stably held by appropriately selecting the spring constant of the spring member of the urging member. Inside.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A holding mechanism for a columnar optical member according to each embodiment of the present invention shown in FIGS. 3 to 14 will be described below in detail.

First, a first embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

As shown in the overall perspective view of FIG. 3 and the axial cross-sectional view of FIG. 5, the holding mechanism 10a of the first embodiment is generally a columnar light guide 1 in a hollow cylindrical lens barrel 20.
2 are accommodated, and an opening cover member 30 fixed to both ends of the lens barrel 20 with fixing screws 36 is configured to sandwich both end surfaces 14 of the light guide 12 in the axial direction.

That is, the lens barrel 20 has a cylindrical peripheral wall 21, and screw holes 26 for fixing the opening lid member 30 are formed on both end surfaces thereof. The light guide 12
It has an elongated rectangular parallelepiped shape. The length of the lens barrel 20 in the axial direction is slightly shorter than the length of the light guide 12 in the axial direction. 12 is urged in the axial direction to hold it. Opening lid member 30
As shown in the plan view of FIG. 6, the light guide 12 has an opening 32 which is opposite to the end face 14 of the light guide 12 shown by a dashed line and is slightly larger than the end face 14. The four corners 34 of the opening 32 of the opening lid member 30 are rounded, and come into contact with the corner 15 of the end face 14 of the light guide 12. Therefore, the light guide 12 has two end faces 14.
Is clamped by the vicinity of the four corners 34 of the opening 32 of the pair of opening lid members 30 to form the hollow hole 22 of the lens barrel 20.
Is held within.

As shown in the perspective view of FIG. 4 and the cross-sectional view of FIG. 7, the light guide 12 is radially positioned with respect to the opening 32 of the opening lid member 30, ie, the lens barrel 20, by four positioning members 40. It has become so.

More specifically, the positioning member 40 includes first and second pieces 4 on both sides of the connecting portion 40 bent at a substantially right angle.
4, 46 are plate-shaped members extending. The first and second pieces 44, 46 have protrusions 45, 46 formed inward. The four positioning members 40 are used for the light guide 12.
When the light guide 12 is assembled into the lens barrel 20, the first and second pieces 44 and 46 are disposed on both sides of each ridge line 18 of the light guide 12 at a substantially intermediate position in the axial direction of the light guide 12, respectively. While the projections 45 and 47 make point contact with the adjacent outer peripheral surface 16, the outer bending line 43 of the connecting portion 42 abuts on the inner peripheral surface 23 of the lens barrel 20 to elastically support the optical member from four directions. . Any one of the projections 45, 4 of the first and second pieces 44, 46 of the positioning member 10
Temporarily bonding the light guide 12 to the outer peripheral surface 16 of the light guide 12 facilitates the work of incorporating the light guide 12 into the lens barrel 20 together with the positioning member 40.

In the above configuration, the light guide 12 is
The four corners of the end face 14 come into contact with the opening lid member 30, but the contact area is small, and the light transmission loss caused by covering the incident area and the exit area of the light guide 12 is very small. In particular, when light enters only inside the opening 32 of the opening lid member 30, no light transmission loss occurs at the time of incidence. The light guide 12 comes into contact with the positioning member 40 at a substantially middle position in the axial direction, but the contact is a point contact and the contact area is very small, so that the light transmission loss is very small.

Therefore, in this holding mechanism 10a, light transmission loss hardly occurs.

Next, a second embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

In the holding mechanism 10b of the second embodiment, FIG.
As shown in the overall perspective view of FIG.
Schematically, the columnar light guide 12 is accommodated in the cylindrical hollow lens barrel 20, and positioning members 60 are provided near both ends of the lens barrel 20.
The light guide 12 is held in the radial direction by using the light guide 12 and the urging member 70, and the opening cover members 30 are attached to both end surfaces 24 of the lens barrel 20. Are held in the axial direction.

More specifically, a threaded hole 28 is formed in the peripheral wall 21 of the lens barrel 20 near both ends thereof.
In addition, positioning members 60 are provided near both ends of the inner peripheral surface 23.
A protrusion 26 for positioning the position in the axial direction is formed.

As shown in the perspective view of FIG. 12, the positioning member 60 has an opening hole 62 through which the light guide 12 is inserted, and first and second support portions 64 having sharp linear tips 65 and 67. , 66 project toward the inside of the opening 62. The distal ends 65, 67 of the first and second support portions 64, 66 are orthogonal to each other and are in line contact with the inner peripheral surface of the light guide 12. Also, the tip 65,
Even if 67 has a certain width, the effect of line contact can be obtained. Also, rounding of the tips 65 and 67 also results in line contact.

As shown in the perspective view of FIG. 11, the biasing member 70 is formed by bending a plate-like spring member, and first and second pieces 74 and 76 extend from both sides of the connecting portion 72 at right angles to each other. ing. The first and second pieces 74, 76 have protrusions 75, 7
7 are formed so as to make point contact with the outer peripheral surface 16 of the light guide 12.

The holding mechanism 10b is assembled as follows. That is, as shown in FIG.
The optical member is inserted into the hollow hole 22, and a pair of positioning members 60 are further inserted from both sides. A pair of positioning members 6
0 is positioned in the axial direction by contacting the outer surface 27 of the projection 26 of the lens barrel 20. Next, as shown in FIG.
A pair of urging members 70 are inserted from both sides of the lens barrel to hold the light guide 12 in the radial direction. At this time, as shown in the sectional view of FIG. 9, the urging member 70 is connected to the first and second support portions 6 of the positioning member 60 via the light guide 12.
It is arranged at a position facing 4,66. And lens barrel 2
By pressing the urging member 70 against the light guide 12 with the holding screw 50 screwed into the 0 screw hole 28, the first and second pieces 74, 76 of the urging member 70 come into point contact with the projections 75, 77. The outer peripheral surface 16 of the light guide 12 is supported by the linear contact between the distal ends 65 and 67 of the first and second support portions 64 and 66 of the positioning member 60. Thus, the light guide 12 is held in the radial direction with almost no light transmission loss due to contact. Finally, as shown in FIG. 8 (III), an opening lid member is fixed to both end surfaces 24 of the lens barrel 20.

As described above, the holding mechanism 10b
In this case, the light guide 12 can be reliably supported in the radial direction with almost no light transmission loss.

In the second embodiment, the urging member 70 is formed using a plate member. However, the urging member 70 may be formed as a holding mechanism 10c according to a third embodiment described below.

That is, as shown in the cross-sectional views of FIGS. 13 and 14, the urging member 80 of this embodiment is formed by bending a rod-shaped member having a circular cross section. The pieces 84, 86 extend at right angles to each other. This urging member 80 has a simpler configuration than the urging member 70 of the second embodiment, and is therefore easier to manufacture. Using the urging member 80, the light guide 12 can be urged to the distal ends 65, 67 of the first and second support portions 64, 66 of the positioning member 60, as in the second embodiment. However, although the contact portions 85 and 87 between the urging member 80 and the light guide 12 are not dots but lines, the light transmission loss hardly occurs even with the line contact.

As described above, the holding mechanisms of the above embodiments hardly cause light transmission loss.

The present invention is not limited to the above embodiments, but can be implemented in various other modes.
For example, the optical member may have a columnar shape, a triangular prism shape, or a polygonal prism shape of five or more. In the first embodiment,
A configuration in which the optical member is sandwiched only in the axial direction by using the opening lid member and the radial support by the positioning member is eliminated is possible. Conversely, in the second and third embodiments, the positioning member and the urging member are used. A configuration in which the optical member is held only in the radial direction and the axial support by the opening lid member is eliminated is also possible. Further, in the second and third embodiments, the arrangement and the number of the support portions of the urging member and the positioning member in the optical axis direction and the direction perpendicular to the optical axis can be appropriately selected.

[Brief description of the drawings]

FIG. 1 is a perspective view of a light guide.

FIG. 2 is a sectional view of FIG.

FIG. 3 is an overall perspective view of a light guide holding mechanism according to the first embodiment of the present invention.

FIG. 4 is a perspective view of a main part of the light guide of FIG. 3;

5 is an axial sectional view of FIG. 3;

FIG. 6 is a plan view of the opening lid member.

FIG. 7 is a sectional view taken along the line IV-IV in FIG. 5;

FIG. 8 is an overall perspective view of a light guide holding mechanism according to a second embodiment of the present invention.

FIG. 9 is a sectional view taken along a direction perpendicular to the axis of FIG. 8;

10 is an axial sectional view of FIG.

FIG. 11 is a perspective view of a biasing member.

FIG. 12 is a perspective view of a positioning member.

FIG. 13 is a sectional view perpendicular to the axis of a light guide holding mechanism according to a third embodiment of the present invention.

14 is an axial sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10a, 10b, 10c Light guide holding mechanism 12 Light guide 14 End surface 15 Angle 16 Outer peripheral surface 18 Ridge line 20 Lens barrel 21 Peripheral wall 22 Hollow hole 23 Inner peripheral surface 24 End surface 26 Projection 27 Outer surface 28 Screw hole 30 Opening lid member 32 Opening 40 positioning member 42 connecting part 44 first piece 45 projection 46 second piece 47 projection 50 holding screw 60 positioning member 61 body part 62 opening hole 64 first support part 65 tip 66 second support part 67 tip 70 urging member 72 connection Part 74 First piece 75 Projection 76 Second piece 77 Projection 80 Energizing member 82 Connecting part 84 First piece 85 Tangent line 86 Second piece 87 Tangent line

Claims (2)

[Claims] 1. A cylindrical lens barrel, a columnar light guide housed in the lens barrel along an axis, and disposed at least at two axial positions in the lens barrel, all around the outer peripheral surface of the light guide. At least two line contact members supporting the columnar optical member in line contact with a part of the circumferential direction of the light guide; Placed in two places,
Point contact or line contact with the outer peripheral surface of the light guide, comprising at least two urging members for urging the light guide to the line contact member, between the urging member and the line contact member, A holding mechanism for a columnar optical member, wherein the light guide is held. 2. The urging member comprises a spring member. The lens barrel further includes a presser screw member attached to the urging member so as to be movable in a radial direction so as to face the urging member. The holding mechanism for a columnar optical member according to claim 2, wherein the holding member is pressed against the columnar optical member to elastically urge the optical member against the line contact member.