JPS60120313A - Light diffusing element - Google Patents

Abstract

PURPOSE:To obtain speediness and a large variable amount of light diffusivity by composing a light diffusing element of an elastic body and a member which has numbers of fine openings, and either projecting or drawing the elastic body from said fine openings and making the light diffusivity variable. CONSTITUTION:Surfaces in the openings 2 of a elastic body 3 are held nearly plane and incident luminous flux is transmitted through the elastic body 3 without being diverged by the surfaces in the openings 2. When pressure is applied to a movable part 4, the elastic body 3 projects from the opening 2 to form extremely small convex surfaces. Consequently, an incident luminous flux 5 is diverged by the formed convex surfaces to obtain light diffusivity on the whole. At this time, the convex forms of the surfaces vary according to the pressure applied to the movable part 4, so the intensity of the light diffusivity is varied. Further, pressure may be applied to the member having the fine openings while the movable part 4 is fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light diffusing element with variable light diffusing properties that can be used as a focusing plate or an illumination plate.

This type of element with variable light diffusivity can be made transparent by attaching a liquid to a matte surface, but it is difficult to obtain reversibility when attaching a concentration of colloid dispersed in a liquid. In the latter case, rapid changes cannot be achieved. Furthermore, in either case, the use of liquid requires a container of some kind, which complicates the structure.

The present invention solves the above-mentioned drawbacks and provides a light diffusing element that can quickly and widely vary the amount of light diffusivity with a simple configuration.

The light diffusing element of the present invention is characterized in that it is made of an elastic body and a member having a large number of minute apertures, and the elastic body is made to protrude or sink from the minute apertures to make the light diffusivity variable. The present invention will be explained in detail using the drawings.

FIG. 1 shows a sectional view of the basic configuration of the present invention.

1 is a container in which the elastic body 3 is placed, 2' is a large number of minute openings 2
This member is fixed to the container 1.

Reference numeral 4 denotes a transparent movable part, which is movable in the vertical direction on the paper.

FIG. 2 is a plan view of a member 2' having a large number of openings 2. As shown in the figure, a large number of minute openings 2 of circular or arbitrary shapes are arranged irregularly. The arrangement of the openings is preferably irregular, and the member 2' having a large number of openings is preferably formed of a transparent material.

Figure 1 shows a state in which no force is applied to the movable part 4. Figure 6 shows a state in which pressure is applied to the movable part 4, and as shown in the figure (the elastic body 6 protrudes from the opening 2,
Forms a minute convex surface. For this reason, the incident light beam 5 is diverged by the formed convex surface to become a diverging light, and the whole has light diffusing properties. At this time, since the convex state of the convex surface formed changes depending on the pressure applied to the movable part 4, the intensity of light diffusivity can be changed.

In addition, as another example, the same effect can be obtained by bonding an elastic body and a member having minute openings and applying negative pressure to the movable part to form a large number of minute concave surfaces on the surface of the elastic body.

Further, in the configuration shown in FIG. 1, the movable part 4 may be fixed and the member having the minute opening may be moved by applying pressure.

It is also possible to form the container 1 with a piezo element and use the change in volume when voltage is applied.

Further, in FIG. 1, by making the surface of the movable part 4 a reflective surface, a reflective light diffusing element can be obtained.

Further, methods for driving the movable part include a method in which the container is threaded and the movable part is screwed into the container, and a method in which the movable part is formed of a ferromagnetic material and driven by an electromagnet.

The magnetic material used in the present invention has the property (elasticity) that it deforms when force is applied to the object, and as long as the applied force is not too large (within the elastic limit), the deformation returns to its original state when the force is removed. can be used.

In a normal solid, the maximum strain (limit strain) within its elastic limit is about 1 inch. In addition, in vulcanized elastic rubber, the elastic limit force (very thick (its limit strain is 10
Close to 00%.

In the optical element according to the present invention, an elastic modulus depending on the characteristics of the optical element to be formed is used as appropriate, but in general, in order to easily obtain large elastic deformation, or to make the state after deformation optically more homogeneous. In order to achieve this, it is preferable to use a material with a small elastic modulus.

In addition, the elastic modulus (G) is G −p/r (ρ−stress, r−
elastic strain). Further, elasticity that causes large deformation with small stress is called high elasticity or rubber elasticity, and therefore, this type of elastic body can be particularly preferably used in the present invention.

Such rubber elastic bodies include natural rubber, commonly known as "rubber," and styrene-butadiene rubber (8BJ,
Butadiene rubber (BR), isoprene rubber (IR), ethylene propylene rubber (EPM), butyl rubber (IB), chloroglene rubber (OR), acrylonitrile-butadiene rubber (NBR), urethane rubber (
U), silicone rubber (8i), fluorine rubber (F'PM
), polysulfide rubber, polyether rubber (POR, CHR
Synthetic rubbers such as CHC) can be mentioned. All of these exhibit a rubbery state at room temperature. However, polymeric substances generally take one of a glass state, a rubber state, or a molten state depending on the degree of Brownian motion of the molecules. Therefore,
A polymer substance that exhibits a rubbery state at the operating temperature of an optical element can be used as the elastic body of the present invention. Therefore, for example, vulcanization of natural rubber is nothing but a process that determines the elastic modulus.

In the present invention, it is desirable that the elastic body used be capable of large deformation with small stress, and for this purpose, adjustment of the crosslinking state is important.

However, a decrease in elastic modulus (a tendency to show large deformation with small stress) also leads to a decrease in strength (therefore, in order to maintain the strength suitable for the purpose of the light diffusing element to be formed, It is necessary to select the elastic body to be used appropriately.The elastic modulus of the elastic body must also be measured by, for example, tensile, bending, or compression methods, depending on the type of stress depending on how the light diffusing element is used. It will be done.

The elastic body used in the present invention has an elastic modulus of 10 to 10 smaller than that of a normal solid, and has an elastic modulus of iQ
dyne/c- or less, particularly preferably 5×10'dy
neAJ or less, and the lower limit is 0, which is preferably smaller as long as the elastic body does not spill, unlike normal liquids, when the elastic body constitutes the light diffusion element.In addition, the light diffusion element is often kept at room temperature. However, since it may be used particularly at high or low temperatures, the above range of elastic modulus is at the operating temperature of the light diffusing element.

The hardness and softness of an elastic body depend to some extent on its elasticity. J
IS K6301 stipulates a method of applying a minute strain to the surface of a sample using a spring and evaluating the hardness of rubber based on its penetration, which can be easily determined.

However, if the elastic modulus is as low as 10 dyn/cJ or less, it cannot be measured using the above method, and in that case, it is evaluated by the penetration using a 1/4-inch micro-consistency meter according to J 1 B K 2808. do.

In addition, when the elastic modulus is small, it is difficult to measure it by "tensile and elongation" as a measurement method, so the value can be determined by compression (deformation for 5 times) and correspondence with the penetration of the tip.

Rubber elastic materials do not require vulcanization, such as ethylene-vinyl acetate copolymers and A-B-A type butadiene-styrene block copolymers, in addition to the conventional vulcanization (crosslinking) method. It can be obtained by appropriately gelling a substance or a chain polymer by controlling the molecular chain length between the bridge points.

In all of these, the elastic modulus is controlled by adjusting the crosslinking state, the combination of molecules in the block copolymer, the gel state, etc.

In addition, depending on the structure of the elastic body itself, in addition to controlling the elastic body, it is also possible to change and adjust its properties by adding diluents and fillers. KB104 GEL (Product name)
) and a catalyst (product name: Catalyst-104, Shin-Etsu Chemical Co., Ltd.) and a diluent (product name: 几TV Thinner, Shin-Etsu Chemical Co., Ltd.).1 As the amount added increases, the hardness and tensile strength decrease. On the contrary, elongation increases.

As a method for deforming the optical surface at the opening of the elastic body, in addition to external force, it is also possible to use volume changes due to thermal expansion and contraction, sol-glu change, etc. using the above-mentioned materials.

The member having openings for forming the optical surface of the elastic body may be one in which the openings are provided in a flat plate~ゝ0 The light diffusing element formed by these openings is affected by the external force applied to the elastic body or the volume of the elastic body. By changing the shape, the shape can be changed arbitrarily, and the degree of change can be controlled by feedback while detecting the effect.

As described above, according to the present invention, a light diffusing element can be obtained which can quickly and widely vary the amount of light diffusivity with a simple configuration, and can be used as a focusing plate or an illumination plate. Moreover, if the light diffusing element of the present invention is used as a window glass, it is also possible to make the functions of the transparent glass and the frosted glass variable.

[Brief explanation of the drawing]

Figures 1 and 3 are cross-sectional views of the basic configuration of the light diffusing element according to the present invention, with Figure 1 showing a state in which no pressure is applied to the movable part, and Figure 6 showing a state in which pressure is applied to the movable part. . FIG. 2 is a plan view of a member having a large number of minute openings used in the light diffusing element of the present invention. 1...-Container 2...Opening 21...Member with opening 3-@・Elastic body 4・■Movable part 5o-Incoming light beam 6...Divergent light

Claims (1)

[Claims] (1) A light diffusing element comprising an elastic body, a member having a large number of minute openings, and a light diffusing property made variable by making the elastic body protrude or sink from the minute openings.