JPH03209293A - Surface type illuminating material and surface type illuminating body - Google Patents

Abstract

PURPOSE:To extend the utilization range by forming a plate-like transparent organic glass molded goods where a bubble group consisting of many small bubbles exists inside one-sidedly. CONSTITUTION:This illuminating body is the organic glass molded goods where the bubble group consisting of many small bubbles 3 exists inside one-sidedly and which is desirably the plate-like transparent one. In the case of providing a reflection layer 4 on the back of a material 1, light made incident from the lower end face 2a of the material 1 takes a complicated course in accordance with the incident angle thereof. Namely, as to the light which advances in a transparent part 2, the light whose angle made with a boundary is smaller than a critical angle is diffused to the outside of a system as it is and the other light L2 having the larger angle than the critical angle is diffused to the outside of the system while it is successively cast and reflected on the bubble 3 and the reflection layer 4. The light L3 having the smaller angle than the critical angle is totally reflected on the boundary of a surface 2c again and goes on a very complicated path. Thus, the illuminating body is used as a display utilizing edge lighting and lighting for appreciation, drawing and copying an original picture in animation.

Description

[Detailed description of the invention] [Purpose of the invention]

[Industrial Application Fields] The present invention is useful as illumination bodies for displays, signboards, decorative materials, backlights for liquid crystal displays or televisions, for viewing or appreciating negative or positive films, and for copying original drawings in drafting or animation. The present invention relates to solid lighting materials and solid lighting bodies. [Prior Art] (1) Background The development of solid light emitters has been a long-held dream of electrical engineers. For this reason, EL light emitting devices that utilize electrofluorescence have already been developed, but due to their low luminance per area, they have not yet reached the stage of practical use. A device in which a light source such as a fluorescent light is covered with a light scattering plate such as opal glass or a cloudy plastic plate is used. +21 Problems with the conventional technology However, with the above-mentioned solid-state lighting device, the longer the distance from the light source to the scattering plate, the more uniform the illumination becomes, but on the other hand, the illuminance decreases in inverse proportion to the square of the distance, so the uniformity of illuminance becomes less uniform. In order to harmonize the contradictory conditions of increasing lightness and decreasing brightness, it is necessary to create something profound with a certain degree of depth and a large number of light sources. Incidentally, in order to further enhance the decorative effect of acrylic resin, especially its light transmittance and light diffusivity, as described in Japanese Patent Publication No. 52-16138, an appropriate amount of water is added to the raw material when molding an acrylic resin plate. A method has been proposed in which a foamed sheet is made by heating and foaming the resulting foamed sheet. However, according to this known technique, the surface of the resulting foamed sheet becomes uneven due to the bubbles generated during heating, and the surface smoothness deteriorates. Not only is it lost, but the inner walls of the generated bubbles are also uneven and lack luster, and the incident light from the end surface is rapidly attenuated, so it is not suitable for edge lighting, and is expected to have a scattering effect on the incident light that intersects with the sheet. It is only possible. [Problems to be solved by the invention] The problems to be solved by the present invention are, for example, displays, signboards, decorative materials, etc. that utilize edge lighting.
An object of the present invention is to provide an excellent illumination material and illumination body that can be used as a backlight for liquid crystal displays and televisions, for viewing negative or positive films, and for copying original drawings in drafting and animation.

[Structure of the invention]

[Means for solving the problem] (1) Progress The present inventors have been engaged in the production and application development of organic glass molded products mainly made of polymethyl methacrylate for many years. Patent application Hei 1-2590
A light reflecting material according to No. 91 was invented. The light-reflecting material based on the previous invention is one in which bubble groups consisting of a large number of small bubbles are unevenly distributed inside a transparent organic glass molded body, and has particularly excellent light diffusivity, and is particularly suitable for surface reflection by edge lighting. When used as a panel, the bubbles within it created a subtle light-scattering effect, making it a unique decorative material. (a) Overview The present invention is an attempt to develop the above-mentioned previous invention and actively utilize the light scattering effect of unevenly distributed bubbles. A solid lighting material, characterized in that it is a transparent organic glass molded article, preferably in the form of a plate, and a linear light source is arranged at at least one edge of the molded article. The present invention consists in a solid-state lighting body characterized by the following: The various elements constituting the invention will be explained in detail below. Generally, it is desirable that the product be shaped like a plate with a uniform thickness, but a plate-like cross-sectional model with unequal thickness is preferable, for example, as a light guide plate for a liquid crystal display. It can take on any other shape, such as a curved plate, cylindrical, cylindrical, conical, elliptical columnar, prismatic, pyramidal, spherical, or other arbitrary shape.However, common to all shapes It is an important feature of the invention that they have a large number of small bubbles unevenly distributed inside them. is the whole (Fig. 1) or a part (Fig. 2 and 3) of one side of the organic glass material 2, and the whole (not strictly defined) of the central part (Fig. 4) or part (Fig. 5). Each of these structures has an excellent light diffusion effect for surface reflection, but from a manufacturing standpoint, the structure shown in Figs. The structure of FIG. 3 is advantageous. In addition,
In the formats shown in FIGS. 2, 3, and 5, it is possible to create arbitrary characters, figures, symbols, patterns, etc. using the aggregates of bubbles 3 (bubble groups), thereby creating a special aesthetic effect. However, if the purpose is only to use it as a surface-emitting type illumination material or illumination body, it can be expressed as Fig. 1 or Fig. 4.
It is preferable to have the structure shown in the figure. Each bubble 3 has a diameter of 0.1~2″/1, preferably 0.2~2″/1
It is preferable that the cells are spherical closed cells of the order of 1'''/. In particular, it is ideal that the inner walls of the cells 3 are also smooth. When the inventive material is formed into a plate shape, the cell group (cell layer) The thickness of the material is preferably in the range of 1/1 to 2/3 of the total thickness of the material.When the light from the light source enters only from one edge of the material, the thickness of It is desirable that the density of the bubbles or the thickness of the bubble portion gradually increases toward the diffusion side. (4) Before manufacturing the cellular organic glass molded article The cellular organic glass molded article described in section (3) is preferably A foamed body consisting of methyl methacrylate and its polymer (however, the degree of polymerization (conversion) can vary) is placed in a mold (usually two polished glass plates are placed together through a gasket). It is produced by curing it with a non-expandable casting material of the same type in a parallel arrangement (parallel arrangement), but at this time, the foamed material of the former mixes with the non-expandable (degassed) casting material. In the above molding operation, if the shape and size of the gel-like material are similar to the cells (i.e., gelling is possible directly on the cell plate without using a special mold). (Of course, a surrounding weir plate is necessary to prevent the material from flowing out of the cell machine), and the resulting molded product will be a laminated layer of a cell-containing layer and a cell-free transparent layer. (See Figure 1), and then completely or partially overlap the foamed material on the bubble-free transparent layer that has hardened to the extent that they do not mix with each other, and then pour the deaerated casting material on top of it. By mold hardening, it is also possible to obtain a product with a sandwich structure in which transparent resin layers sandwich the upper and lower sides of the resin layer containing bubbles (see Figure 4).On the other hand, although this is outside the main purpose of the invention, Foam molding of a molded object containing groups of cells having arbitrary shapes such as letters, figures, symbols, or patterns according to the inner shape of the mold by making the body in a suitable mold separate from the mold. By curing this molded body integrally with the deaerated casting material while inscribed in the mold, any glyphs such as letters, figures, symbols, or patterns can be formed on the - side. It is possible to obtain a molded article (see FIGS. 2 and 3) having a cell group layer with a structure similar to the above.As a modification of the sandwich-like structure shown in FIG. In the above production method, it is preferable to use a powder of a polymer or copolymer of methyl methacrylate (MMA>) as a raw material for preparing the highly viscous methyl methacrylate solution. Such powders generally have rM
Although the MMA polymer is available as "MA polymer beads", the MMA polymer may be prepared by grinding it, or a mixture of the polymer and a high convection MMA monomer produced during the polymerization of MMA may be used. That is, when the above methyl methacrylate is radically polymerized using a polymerization initiator, a phenomenon called the kinetically self-acceleration effect (Tromsdorff effect) occurs, and after the initial lag phase of the polymerization reaction, the reaction rate (Rp ) increases naturally logarithmically. The increase in viscosity occurs in the later log phase, so even if it is possible to incorporate air by stirring during the increase phase, the viscosity increases rapidly and is very difficult to control. On the other hand, when polymerized granular resin is used, the apparent viscosity increases due to the swelling and dispersion of the resin particles, and the required amount of air can be uniformly entrained within the lag phase period, making it easy to use. A uniform state of bubble dispersion, which is the object of the invention, can be obtained. Therefore, the smaller the particle size of the granular resin used here, the greater the apparent viscosity increasing effect, but on the other hand, if it is too fine, it will be difficult to obtain a uniform and perfectly spherical group of bubbles during dispersion. Above, average particle size 10-2
000 μm, preferably within the range of 40 to 1000 μm. Furthermore, the molecular weight of the granular resin is also related to the quality of the generated bubbles. The ratio of the former in the mixture of granular polymethyl methacrylate (beads) and MMA monomer or its prepolymer to constitute the foam layer is preferably approximately 30 to 80% by weight. If the proportion of beads is less than 30% by weight, the plasticity of the agar-like gel will be insufficient and it will be difficult to maintain a predetermined shape, while if it exceeds 80% by weight, it will be difficult to obtain a uniform foam. It becomes difficult. However, if the purpose is to obtain a simple laminate as shown in FIGS. 1 and 4, it is not necessary to limit the above lower limit. (5) Light-reflecting layer It is desirable that the material of the present invention is provided with a light-reflecting layer on the back side of the organic glass molded article as an additional structure. Although the presence of wood chips is not essential for the purpose, the presence of wood chips is effective in increasing the lighting effect (illuminance). This reflective layer means, for example, a mirror attached to one surface of the molded product, or a layer of fine metal particles such as aluminum deposited on one surface of the molded product by means such as vacuum evaporation, sputtering, or ion blasting. However, in order to improve reflection efficiency, it is desirable that there be no substantial voids at the interface between the mirror, plating or vapor-deposited metal layer and the molded product. Since the surface is considered to be a de facto mirror surface,
A thin reflective film formed in close contact with the surface of the molded product using means such as vapor deposition or electroless plating is most efficient. (6) Light-scattering layer The light rays emitted from the irradiated material of the present invention (mainly recognized as the glow of the built-in bubbles) are a collection of lights with different phases, so if left as is, it gives the impression of glare. For this reason, it is desirable to attach a thin scattering film to the surface of the material to disperse the emitted light. (2) Light source Since the material of the present invention functions according to the principle of edge lighting, the light source is preferably a fluorescent lamp, that is, a hot cathode fluorescent lamp (ordinary fluorescent lamp) or a cold cathode fluorescent lamp. Of the above, the latter cold cathode type is particularly preferred. This is due to the fact that the latter can be made smaller in diameter to 6'''/, φ or less, as well as the fact that it does not have a filament inside, and the light source temperature does not rise.However, Since it cannot be lit with ordinary 100 V AC, it is necessary to prepare a DC high-voltage power supply similar to that used for neon tubes, and in order to make the irradiated light from the light source as parallel as possible, parabolic reflectors, condensers, etc. Additional equipment is added as necessary.Even if it is a point light source such as a xenon lamp or krypton lamp, by arranging a large number of them in parallel,
In fact, you can expect an effect similar to that of a linear light source. Therefore, the term "linear light source" as used in the present invention shall mean a virtual linear light source. Referring to the figure, the light incident from the lower end surface 2a of the material 1 takes a complicated course depending on its angle of incidence. That is, the light traveling inside the transparent part 2 has a critical angle (
For polymethyl methacrylate, the critical angle i at the air interface
o=sin O, 669≠41°) is directly diffused out of the system (however, it is reflected on the side with the reflective layer 4 and returns into the system), but other light is emitted by air bubbles as shown in the figure. 3. While hitting the reflective layer 4 one after another and being reflected, those larger than the critical angle L2 are radiated out of the system, and those smaller than the critical angle are totally reflected again at the interface of the surface 2c through a very complicated path. However, in any case, when the light collides with a bubble and is reflected, it makes the bubble shine, so that almost all of the incident light is effectively used as illumination light. Furthermore, since the path of light is extremely complex, with long and short paths mixed together, relatively uniform illuminance can be obtained as a whole. However, since the diffused light contains a large amount of polarized light, the surface 2
It is preferable to place a polarizing plate or add a scattering plate to reduce glare. Note that if the reflective layer 4 is not present, the loss will be somewhat large, but instead it can be used as a double-sided light emitter. As a result of the experiment, the distance from the incident surface 2a! ! 1fD is 50cm
It was found that there was no significant change in illuminance up to a certain extent, and that it could withstand practical use up to a distance of about 100 cm. This is thought to be due to the fact that the light path inside the material is extremely complex, as can be seen in this figure, and the light path for dispersing to the front of the material has significant lengths and shortnesses, and that the light is mixed. be done. However, it goes without saying that it is preferable to arrange the light sources on all end faces of 2 as much as possible. On the other hand, when the bubbles are uniformly dispersed throughout the interior of the plate, it has been confirmed that the attenuation of incident light is significant and the plate cannot be used for practical use. Therefore, the transparent part 2 without air bubbles
However, regardless of whether it is linear or not, the presence of a transparent portion that essentially serves as a light path is necessary for the purpose of the invention. [Example] Hereinafter, according to the example, 1! of the invention product! ! Although construction examples, assembly examples, and comparative examples are shown, the examples are of course for illustrative purposes and do not limit the connotation or extension of the inventive idea. 100 parts of MMA monomer and 0.1 part of a polymerization initiator were mixed, and 70 parts of granular PMMA having a particle size of 400 μm were mixed therewith and stirred until it became a slurry. Separately, place a metal mold of the same shape and size on the edge of a square polished glass plate that has been cleaned and dried in advance, pour the above slurry into it until it reaches a depth of 172 mm, which is the thickness of the product, and leave it at room temperature. After solidification, the mold was removed. After that, a mold is assembled using another glass plate and a gasket, and prepolymerized PMMA syrup is injected into the mold, hardened and post-treated, and then the four peripheries of the molded product are cut and By polishing, a molded product (plate) having a thickness of 6 mm and having a bubble layer 3 on the surface (lower surface in the figure) side as shown in FIG. 1 was obtained. An aluminum vapor deposition film M4 was applied to the back surface (upper surface in the figure) of the above molded product according to a conventional method to obtain a solid lighting material 1 as shown in FIG. Space below C) Installation Preparation 1i In Manufacturing Example 1 above, mirror 4' was pasted on the back side of the bubble-containing molded product instead of vacuum deposition, and mirror 4' was also pasted on the end face other than the lower edge, A solid lighting material 1' (see FIG. 7) was obtained. Ori Takumi Y Solid lighting material 1' of the above production example 2 (150X150X
Attach a thin light diffusing plate to the surface side of the 9mm) and place it inside the cold cathode discharge tube] 1. Attached high-voltage power supply equipment (not shown)
By inserting the parabolic reflector 12 into the ridge opening 14 of the house-shaped casing 13 of the light source device 10, the solid illumination body 20 shown in FIG. 7 was obtained. Saitaku λ The solid illumination body 20 (invention example) obtained in the above assembly example is separated from the two solid illumination bodies (A, B) shown in FIG. 8 and the distance from the light source S (cold cathode discharge tube). The illuminance was compared at the point of 11t100mm. The results were as shown in the table below. (The following is a blank space.) FIG. 9 shows an example in which the light source device 10 is also added to the upper part of the illumination body of Assembly Example 1, and the width is widened to create an observation device 200 for positive film. The device of this example has a much shallower depth and greater illuminance than conventional devices of the same type. Note that the reference numeral 201 in the figure indicates a clip for securing the negative.

【Effect of the invention】

As explained above, the present invention relates to a flat organic glass material with bubbles having a smooth surface, a composite illumination material having particularly uniform light scattering properties, and illumination bodies, such as displays and signboards using edge lighting. , by providing excellent lighting materials and lighting bodies that can be used as decorative materials, backlights for liquid crystal displays or televisions, for viewing negative or positive films, and for copying original drawings in drawings and animations. contribute to the development of the industry and the interests of consumers.

[Brief explanation of drawings]

1 to 5 are schematic cross-sectional views showing various structures of the lighting material according to the invention, FIG. 6 is a schematic cross-sectional view explaining the invention in detail, and FIG. 7 is a schematic cross-sectional view of the lighting body according to the invention. FIG. 8 is a schematic vertical cross-sectional view of a solid lighting body used as a comparative example, and FIG. 9 is a cutaway front view showing another example of the lighting body according to the invention. The meanings of the symbols in the figure are as follows: +1': Entire inventive lighting material; -2: 1.1'' transparent part; -2a: lower edge of 2, 2b: upper edge of 2, 2c: 2 Surface, 2d:2 backside; 3: Bubbles (or bubble layer) in 1.1'; 4:1 light reflection layer, 4゛:1'' light reflection layer (mirror) 5:1 light Scattering layer; 10: Light source device; ・11: Cold #& polar discharge tube; 12: Parabolic mirror; 13: Casing; 100, 200: Entire invention proof body. 201: Negative locking clip. S: Light source. L, ~L,: incident light ray. Figure 6 Figure 7 Figure 8 Procedural amendment January 30, 1990 Figure 9 2゜3゜4゜Name of invention Solid lighting material and solid lighting body Relationship to the case of person making amendments Patent application Address: 3-7-17 Nitta-cho, Niihama City, Ehime Prefecture Name: Nissen Chemical Industry Co., Ltd. Representative - Yoshikazu Miya

Claims (1)

[Scope of Claims] 1. A surface lighting material characterized in that it is a transparent organic glass molded article, preferably in the form of a plate, in which bubble groups consisting of a large number of small bubbles are unevenly distributed. 2. Claim 1, wherein the bubble group is unevenly distributed along one surface of the molded product.
Lighting materials listed. 3. The lighting material according to claim 1 or 2, wherein a reflective layer is present on the back surface of the molded product. 4. The lighting material according to any one of claims 1 to 3, wherein the edges of the molded product other than the edges on which the light source light is incident are covered with a light reflecting layer. 5. The lighting material according to any one of claims 1 to 4, which has a light scattering layer on the surface of the molded product facing the light reflection layer. 6. A light reflecting layer is present on the back of an organic glass molded product in which bubble groups consisting of a large number of small bubbles are unevenly distributed. A linear light source is disposed on at least one edge of the molded product. A surface illumination body characterized by: