JPH0410561Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a light bulb that converts a point light source such as a light bulb into a linear light source by using multiple optical fibers in the optical transmission path and an array terminal at the output light end. The present invention relates to a structure in which the guide is a linear light source with a constant output light intensity distribution over the illumination width.

(Prior Art) Generally, a linear light source is required to have a constant light intensity distribution. This type of point light source linear light source conversion ride guide, as shown in FIG. The optical fibers 5 are located on a linear axis on a plane including optical fibers arranged in a straight line in the lateral direction, and the length of each of the many optical fibers 3 is equal to the center and end portions of the array terminal 4. Although there are some differences,
Almost the same. Therefore, even if a plastic fiber or a multi-component fiber with large transmission loss is selected as the optical fiber 3, the difference in optical transmission loss due to the difference in optical fiber length can be ignored, and the output light intensity distribution over the illumination width is almost constant, which is a problem. There isn't.

(Problems to be Solved by the Invention) However, due to physical factors etc. in the installation conditions of the ride guide, as shown in FIG. When the fiber input light end 6 is forced to be located on a non-straight axis, that is, when the fiber output light end 5 is installed in a curved manner on a plane in which the optical fibers are arranged in a straight line, Particularly when the curvature is high, there is a considerable difference in length between the optical fiber 3a located on the inside of the curvature and the optical fiber 3b located on the outside of the curvature. This length difference can be ignored if a fiber with low transmission loss, such as a quartz fiber, is selected for the optical fiber 3, but if a fiber with large transmission loss, such as a plastic fiber or a multi-component fiber, is selected, the difference in fiber length can be ignored. The difference in transmission loss due to the length difference cannot be ignored.

For example, in a light guide as shown in Figure 4,
When the optical fiber 3 is made of a material with a large transmission loss, such as a plastic fiber or a multi-component fiber, the light from the point light source 1 is input to the fiber input light end 6, and the output light emitted from the fiber output light end 5 is If the light intensity distribution between the illumination widths is measured, the distribution will be as shown in FIG. 2, which does not satisfy the conditions for a linear light source.

(Technical issue) Therefore, in this invention, even if the incident end and the outgoing end of the light guide are on the non-linear axis as described above, the structure is such that the output light intensity distribution across the illumination width is constant. This is a technical issue.

(Technical Means) The present invention was made to solve the above technical problem, and includes a large number of optical fibers of equal length, a fixture that bundles one end of the group of optical fibers as an incident light end, and an array terminal device arranged linearly in at least one row or more in the lateral direction with each optical fiber at the other end as the output light end, and the input light end and the output light end are connected in the lateral direction as described above of the output light end. When the group of optical fibers is curved so as to be located on a non-linear axis on a plane containing optical fibers arranged in a straight line, the lengths of the optical fibers are uneven due to this curvature. This is a light guide characterized in that a portion of the light guide is housed in a fiber length adjustment section.

That is, by eliminating the difference in the length of each optical fiber 3 that occurs when the light guide is installed in a curved manner, the lengths of the optical fibers 3 are the same, and as shown in FIG. A fiber length adjustment unit 8 is provided on the side where the transmission path length is shortened, that is, on the optical fiber 3a side in the figure, and adjusts the uneven length of the optical fiber 3 caused by bending, that is, the extra length fiber, to the fiber. It is stored in the length adjustment section.

(effect) The above technical means works as follows.

As shown in FIG. 1, by making the length of the multiple optical fibers 3 constituting the light guide light transmission section constant, the transmission loss of each optical fiber is almost the same, and the fiber output light end 5 In order to make the emitted light intensity distribution uniform, the light guide is installed in a curved manner due to physical factors, etc., and the fiber input light end 6 and the fiber output light end 5 are arranged in a straight line at the output light end 5. Fiber 3 (X-X in Figure 1)
The optical fiber 3a is an uneven part of the optical fiber that occurs when the optical fiber is on a non-linear axis on a plane containing
By storing the extra length in the fiber length adjustment section 8, the optical fiber 3 is prevented from being subjected to abnormal stress within the protective cover 7, making it easier to meet the constraints of installation conditions.

(Embodiment) Fig. 1 shows an embodiment of the present invention, in which the light guide is curved due to physical factors, and the fiber input light end 6 and the fiber output light end 5 are aligned on the non-linear axis as described above. A fiber length adjustment unit 8 that covers a large number of optical fibers 3 of the same length, which are the optical transmission medium of the light guide, with a protective cover 7, and stores the extra length optical fibers generated on the optical fiber 3a side in a ring shape. It is provided in close proximity to the fiber focusing fixture 2. The fiber focusing fixture 2 has a circular or oval shape, and uniformly receives the light input from the point light source 1, and at the fiber output light end 5, the optical fiber is at least
The array terminals 4 are arranged in one or more rows in the X-ray direction.
is fixed. The optical fiber 3 stored in the fiber length adjustment section 8 is stored in such a way that no loss occurs due to bending, and if no loss occurs due to bending, there is no need to store it in a ring shape. In addition, it is necessary that the size is such that fiber bending loss does not occur.

Furthermore, the shape of the fiber length adjustment section 8 does not have to be a flat circular shape as shown in FIG. 1, but it has a shape that does not become an obstacle when installing the light guide and does not cause loss due to bending of the optical fiber stored therein. If so, no particular restrictions are required. In addition, an optical fiber that does not have enough extra length to be accommodated in the fiber length adjustment section 8, an optical fiber that is close to the optical fiber 3b in the center in the figure,
Adjust the length by gently waving it inside the protective cover 7.

(effect) This invention has the following unique effects.

In a light guide using plastic fiber or multicomponent fiber, a linear light source with a constant light intensity distribution over the illumination width can be obtained even if the installation conditions of the light guide are restricted.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, Fig. 2 shows the light intensity distribution between the illumination widths of the light guide as shown in Fig. 4, and Fig.
The figure shows an example of a conventional point light source linear light source conversion light guide, and FIG. 4 shows an example of a light guide in which the transmission path length varies depending on the installation conditions. 1... Point light source, 2... Fiber focusing fixture,
3, 3a, 3b... Optical fiber, 4... Array terminal, 5... Fiber output light end, 6... Fiber input light end, 7... Protective cover.

Claims (1)

[Scope of utility model registration request] a large number of optical fibers of equal length; a fixture that bundles one end of the group of optical fibers as an incident light end;
and an array terminal fitting arranged linearly in at least one row or more in the lateral direction with each optical fiber at the other end as the output light end, and the input light end and the output light end are connected in the lateral direction as described above at the output light end. When the group of optical fibers is curved so as to be located on a non-linear axis on a plane including optical fibers arranged in a straight line in is housed in a fiber length adjustment section.