JPS6392909A - Condenser - Google Patents

Abstract

PURPOSE:To increase the incident efficiency of light into an optical fiber by arranged the reflecting face of a 2nd reflecting plate on the extension of the reflecting face of a 1st reflecting plate and making the reflected light on the extending part incident on the reflecting face of the 1st reflecting plate. CONSTITUTION:The 1st reflecting plate 15 has a conical reflecting face 8a and a hole 9 into which a light source 10 is to be inserted is formed on the center of the reflecting face 8a. On the other hand, a circular hole 16b opposed to the optical fiber 11 is formed on the center of the 2nd reflecting plate 16. Since incident light on the optical fiber 11 is the sum of direct incident light a1 on the optical fiber 11, light a2 reflected on the reflecting face 8a and light a3 obtained by reflecting light on a reflecting face 16a, making the reflected light incident on the reflecting face 8a, reflecting the incident light on the reflecting face 8a and the making the reflected light incident on the optical fiber 11, the incident efficiency of light on the optical fiber 11 can be increased by about 30% as compared to a case using only an ordinary reflecting plate 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a condenser that supplies light to a liquid crystal display device or the like.

[Conventional example]

Figures 4 to 7 are explanatory diagrams of the condenser. Figure 4 is a sectional view showing an example of the concentrator, and Figure 5 is a schematic diagram of another example of the concentrator that supplies light to the optical fiber. , FIG. 6 is an explanatory diagram showing the arrangement of the optical fiber and the condenser, and FIG. 7 is an explanatory diagram of the design of the reflection plate of the condenser.

In Fig. 4, reference numeral 1 denotes a condenser, a plurality of light sources 3 are provided on the inner bottom surface of the case 2, and a light diffusing plate 4 made of translucent synthetic resin (acrylic material) is placed above the light sources 3. A liquid crystal display plate 5 is laminated on the light diffusing plate 4, and these are fixed between the upper part 2a of the case body 2 and the lamp house 6.

The light from the light source 3 is diffused by the light diffusing plate 4 and illuminates the liquid crystal display plate 5 for display.

However, in the above liquid crystal display device, when the brightness of the light source 3 is increased, the temperature of the light source 3 also increases by 30 degrees due to the heat of the emitted light.
There was a problem in that the temperature rose by about C to 50C, impairing the function of the liquid crystal display panel 50.

Therefore, as shown in FIG. 5, a cylindrical reflector plate 8 having a dome-shaped reflective surface 8a is housed in a metal casing 7, and a light source 10 is housed in the center hole 9 of the reflector plate 8. 10 was irradiated directly onto the optical fiber 11, and the light reflected by the reflective surface 8a was irradiated onto the optical fiber 11, and the body 12 was irradiated through the optical fiber 11 to display a display on the liquid crystal display panel 13. Note that 4 is a light diffusing plate.

In FIG. 6 of this display device, the maximum incident angle of light entering the optical fiber 11 from the light source 10 is 0°,
The θ. If the angle of incidence with respect to the upper and lower surfaces of the optical fiber 11 determined corresponding to is 08.

θ. =201 and θ1 is determined by the following equation.

sin θ, =≠1. 1 However, n is the refractive index of the core material constituting the inside 11c of the optical fiber 11, and n is the outside nd of the optical fiber 11.
t - The refractive index of the cladding material.

By the way, now, n = 1,495. n,=1,402
Then, sin θ, 0.5 in 01, therefore 30° in 01
, θ. It will be 60° in the middle. Therefore, in the past, both ends 8a1, 8a of the reflecting surface 8a of the reflecting plate 80! and both ends 11a of the optical fiber 11.

The included angle α connecting 11b is the maximum incident angle θ of the optical fiber 11. , that is, 60°.

[Problem that the invention seeks to solve]

However, under the above configuration, when light is emitted from the light source 10, the light that enters the optical fiber 11 is reflected by the light that enters the optical fiber 11 directly from the light source 10, and the light that is reflected by the reflective surface 8a, and the light that enters the optical fiber Maximum angle of incidence θ of 11
. There is a problem that only light has an incident angle smaller than θ1 (30°) corresponding to , and the light incidence efficiency is poor.

Therefore, as shown in FIG. 7, it is conceivable to extend the end portions 8 al + 8 al of the mortar-shaped reflective surface 8 a as shown by the dotted lines in the figure, and provide extended portions sb, sb.
The incident angle θ of the light reflected at these portions 8b, , 8b.

is the angle of incidence of the optical fiber 11, # (30°).

The light does not enter the inside of the optical fiber 11 effectively, and in this case as well, the light incidence efficiency is poor, so a configuration as shown in FIG. 6 has to be adopted.

The present invention aims to eliminate the above-mentioned drawbacks of the conventional art, and an object of the present invention is to provide a light concentrator that is more efficient at entering an optical fiber than the conventional art.

[Ninth way to solve the problem]

In order to achieve the above-mentioned object, the present invention forms a first angle that connects both ends of a reflecting surface and both ends of a light guide so as to be the maximum angle of incidence of the light guide, and inserts a light source in the center. and a second reflecting plate having a reflecting surface opposite to the reflecting surface of the first reflecting plate, and the reflecting plate of the second reflecting plate is stacked on an extension of the reflecting surface of the first reflecting plate. It has a configuration in which surfaces are arranged.

[Effect]

According to the present invention, the second reflector is provided on the extension of the reflective surface of the first reflector.
The reflective surface of the first reflective plate is arranged, the reflective surface of the first reflective plate is substantially extended, and the reflected light from the extended part is incident on the reflective surface of the first reflective plate, and one reflected light is reflected by the light 7 eyeper. Since the light is made to enter the interior, the efficiency of entering the optical fiber can be increased by approximately 30% compared to the conventional example.

〔Example〕

The present invention will be explained below based on the accompanying drawings.

1 to 3 are explanatory diagrams of the invention, FIG. 1 is an explanatory diagram showing the arrangement of a condenser and an optical fiber, and FIG. 2 is an explanatory diagram of the invention. A plan view of the second reflection plate and FIG. 3 are enlarged cross-sectional views of essential parts of the condenser. Note that the same parts as in the conventional example shown in FIGS. 4 to 7 are given the same reference numerals.

In Figures 1 and 3, 15 is a condenser, 7 is a metal casing, and 8 is a condenser.
is a cylindrical first reflecting plate housed in the housing 7, and has a cone-shaped reflecting surface 8a, and a hole 9 into which a light source 10 is inserted is provided in the center of the reflecting surface 8a. . And ends 8a1, 8a of the reflective surface 8a.

The included angle α of the line connecting the end portions 11a and llb of the optical fiber 11 is the maximum incident angle θ of the optical fiber 11 in advance. That is 6
It is set to 0°. Reference numeral 16 denotes a cylindrical second reflecting plate having a cone-shaped reflecting surface 16a facing the reflecting surface 8a of the first reflecting plate 8, and a circular hole 16b facing the optical fiber 11 in the center. The first and second reflecting plates 8.16 are stacked on top of each other, and the first reflecting plate 80 and the reflecting surface 8a
The reflection surface 16a of the second reflection plate 160 is arranged on the extension of the reflection surface 16a.

The condenser of the present invention has the above-described structure, and when light is emitted from the light source 10, the light that enters the optical fiber 11 is
Light a that directly enters the optical fiber 11 from the light source 10,
, the maximum incident angle θ of the optical fiber 11 is reflected by the reflective surface 8a. The light a having an incident angle smaller than the incident angle θ1 corresponding to Since the total amount of light a is increased, the efficiency of incidence on the optical fiber 11 can be increased by about 30% compared to the conventional case where only the reflector plate 8 is used.

In addition, the above numerical value of 01m"t is an example, and nl.

Naturally, if the value of n changes, the maximum angle of incidence θ of the optical fiber 11 will change. and the incident angle θ determined accordingly.

should change.

〔Effect of the invention〕

According to the present invention, the second reflecting plate is superimposed on the first reflecting plate to form an extension part on the first reflecting surface, and the light reflected by the extension part is directed to the reflecting surface of the first reflecting plate. Since the light enters the optical fiber and is reflected by the reflecting surface to enter the inner surface of the optical fiber, it has the effect of increasing the efficiency of incidence into the optical fiber by about 30% compared to the conventional method.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of the present invention, and FIG. 1 is an explanatory diagram showing the arrangement of a condenser and an optical fiber.
b) is the first. A plan view of the second reflection plate, FIG. 3 is an enlarged sectional view of the main part of the condenser, and FIGS. 4 to 7 are explanatory diagrams of conventional examples.
Fig. 4 is a cross-sectional view showing an example of a condenser, Fig. 5 is a schematic diagram of a condenser that supplies light to an optical fiber, Fig. 6 is an explanatory diagram showing the arrangement of the optical fiber and the condenser, and Fig. 7 is an explanatory diagram when installing a reflection plate of a condenser. 8...First reflecting plate, 8a...Reflecting surface, 8a+, e8b!・・・・・・End of reflective surface, 10
... power supply, 11 ... optical fiber guide), lla, llb ... end, θ.・・・・・・
...Maximum angle of incidence, α...Included angle, 15...
・Concentrator, 16a...Reflecting surface, θ,...
·Angle of incidence. Figure 1 Figure 2 Figure 3 oz Figure 4 8Ch 8bz

Claims (1)

[Claims] A first reflecting plate, in which a light source can be inserted in the center, is formed so that the included angle of a line connecting both ends of the reflecting surface and both ends of the light guide path becomes the maximum incident angle of the light guide path, and a second reflecting plate having a reflecting surface is formed. 1. A condenser comprising: a stack of reflective plates with both reflective surfaces facing each other, and a reflective surface of a second reflective plate disposed on an extension of the reflective surface of the first reflective plate.