JP2011099899A - Light scattering member and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light scattering member which can be used as a backlight unit of a liquid crystal display apparatus of a liquid crystal television receiver, a portable telephone or the like, an indoor or outdoor illumination unit, or a surface light source unit of an electric display apparatus such as an electric bulletin board and a light sign board, wherein a thin surface light source that receives incident light from one side face thereof and from which extremely excellent and uniform light is emitted, can be obtained and which is inexpensive and unconventional one; and to provide a method for producing the light scattering member. <P>SOLUTION: The light scattering member includes a glass 2a of inexpensive silicate and the glass 2a contains granular bodies 3 each of which has 0.1-50 μm particle size and the refractive index different from that of the glass 2a by 0.001-0.5. Therefore, the unconventional light scattering member 1a is produced to form the surface light source having uniform light quantity in which the light entering from one side face of the glass 3a is scattered by the granular bodies 3 like Rayleigh scattered light and is diffused uniformly and planarly, by emitting the light having planar and uniform light quantity from the main surfaces of the glass bodies 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light guide plate in an edge light type backlight device or the like that scatters incident light from a side surface and emits it as surface light source light from a main surface, or an electric display such as an indoor or outdoor lighting device, an electric bulletin board, an electric signboard The present invention relates to a light scattering member that can be used for a light guide or a surface light emitter that is a surface light source device of the device, and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, backlight devices for liquid crystal display devices such as liquid crystal television receivers and mobile phones include an edge light type and a direct type. In order to provide a uniform surface light source by uniformly diffusing the light, the edge light system uses a light guide plate (corresponding to the light scattering member of the present invention) and diffuses the light incident from its side surface. The light is emitted from the main surface (surface) as surface light source light. In the direct type, a diffusion plate is used, and light incident from the other main surface (back surface) is diffused and emitted from one main surface (front surface) as surface light source light.

  In the conventional backlight device using a cold cathode ray tube as a light source, the direct type described above has been used. However, in recent years, in order to reduce the thickness of the entire liquid crystal display device including the backlight device, an edge light has been used. The type of backlight device has become the mainstream.

  This edge light type backlight device conventionally uses a cold cathode tube or a light emitting diode (LED) as a light source, and is formed with a reflective dot printed on a transparent resin light guide plate as a reflector.

  FIGS. 8A and 8B show a wedge-shaped light guide plate 100 of a surface illuminator on which the reflective dots are printed. FIG. 8A is a perspective view and FIG. When light from the cathode ray tube 101 as a light source is incident on the light incident end surface (side surface) of the wedge-shaped light guide plate 100 formed of an acrylic plate, a large number of printed surfaces on the reflection surface (lower surface) of the wedge-shaped light guide plate 100 are printed. While being reflected by the white printing dots 102, the light travels to the end surface opposite to the light incident end surface while being diffusely reflected, and during that time, a part of the light is transmitted through the upper surface of the wedge-shaped light guide plate 100 and is used as the planar light as the wedge-shaped light guide plate. 100 (e.g., see Patent Document 1 (paragraphs [0025]-[0028], FIG. 1, FIG. 2, etc.)).

  In addition, another conventional example of an edge light type backlight device is formed by using a transparent resin wedge-shaped or planar light guide plate (light guide) that generates forward scattering.

  FIG. 9 is a perspective view of the wedge-shaped concavo-convex light scattering light guide 200 in which the forward scattering of the conventional edge light type backlight device occurs, and a rod-like light source element (on the side of the light scattering light guide 200). For example, a fluorescent lamp 201 is provided, and a reflective film 202 is disposed on the lower surface of the light scattering light guide 200 opposite to the scattered light extraction surface (upper surface). The light incident on the light scattering light guide 200 from the rod-shaped light source 201 has a particle size of 0.005 microns to 50 microns within the light scattering light guide 200, and the refractive index of the light scattering light guide is 0. Light is guided by being scattered by Rayleigh scattering by adding different resin granules in a range of 0.001 or more, and backlight light is emitted from the upper surface of the light scattering light guide 200 during that time. (For example, see Patent Document 2 (paragraphs [0073]-[0074], FIG. 2)).

JP-A-7-159622 JP-A-6-186560

  In the conventional light guide plate 100 and the light scattering light guide 200 of the edge light type backlight device described above, the light source (visible light) introduced from the side is the cold cathode tube 101 and the like, and the light emission is large. It cannot be said that it is effectively used as a surface light source. In recent years, light-emitting diodes (LEDs) that are straight from the cold-cathode tube 101 are being replaced, but even if they are replaced by LED light sources, the light emission is non-linear light that has a certain extent of spread.

  In order to further reduce the size and thickness of liquid crystal television receivers, mobile phones, and the like, if the conventional light guide plate such as the light guide plate 100 is made thin (thinned), the smoothness of the light guide plate cannot be maintained. At this time, even if the incident light source of the light guide plate is an LED, there is a problem that light incident on the light guide plate from the side face leaks in the middle based on the nonlinearity of light generated from the light source.

  As the optical path length of the light guide plate is increased due to the recent increase in size of liquid crystal screens, etc., the influence of light incident on the light guide plate from the side is increased in the middle, and the light from the cold cathode tube or LED light source is increased. Incident light from one side makes it difficult to diffuse light over the entire light guide plate. For this reason, in a large-screen liquid crystal display device or the like, the light guide plate of the edge light type backlight device is made incident from two or more side surfaces, or a direct type backlight device is used instead of the edge light type backlight device. Although it is used, the former is expensive and the latter is large.

  Therefore, a laser diode (LD) having a sufficient amount of light and higher linearity than the LED is used as the light source of the edge light type backlight device, and light is incident on the light guide plate from one side to obtain a sufficient planar light source as a backlight. However, in a conventional resin (solid) light guide plate such as the light guide plate 100, the light path length is extended when the light guide plate is bent or on a large screen due to light scattering due to the above-described birefringence. Accordingly, it becomes difficult to diffuse light throughout the light guide plate 100. In recent years, LDs that emit predetermined polarized light have been developed. If the polarized light of such LDs is used as it is as a light source of a backlight device and a plane light source of the polarized light can be obtained, a liquid crystal display device, etc. In the conventional light guide plate made of birefringence, the backlight that was wasted about half of the light in the polarizing filter can be effectively used without waste. Therefore, it is difficult to realize a polarized wave radiated from the LD. In order to solve this problem, various attempts have been made to reduce the above-mentioned birefringence by adding an anisotropic substance having birefringence opposite to that of copolymerization or the main material in a resin light guide plate. However, it has not yet been realized inexpensively and easily. In addition, the scattering due to the birefringence is difficult to control from this aspect because the change due to stress or the like is severe and difficult to control.

  In addition, in the light-scattering light guide 200, since the light-scattering light guide 200 is a resin material, it has comparatively big birefringence. Due to this birefringence, when the area is large or the light scattering light guide 200 is bent, there is a problem that light cannot be emitted uniformly from the upper surface of the light scattering light guide 200 due to scattering due to birefringence. .

  On the other hand, it is desirable to reduce the thickness as much as possible by adopting a surface light source device from the viewpoint of space saving etc. also in light emitting display devices such as outdoor and indoor lighting devices such as buildings and shops, electric bulletin boards, and electric signboards. However, conventionally, since fluorescent tubes and neon tubes are often used, it is difficult to reduce the thickness. In the case of an electric display device that employs a large number of LEDs as a light source, it can be thinned to some extent, but is extremely expensive.

  The present invention can be used as a backlight device of a liquid crystal display device such as a liquid crystal television receiver or a mobile phone, a surface light source device of an electric display device such as an indoor or outdoor lighting device, an electric bulletin board, an electric signboard, An object of the present invention is to provide an unprecedented light scattering member and a method for manufacturing the same, which is thin and can provide a uniform surface light source that is extremely good with incident light from one side surface.

  In order to achieve the above-described object, the light scattering member of the present invention includes a silicate glass body having a small birefringence and excellent workability and flatness as compared with a resin material, and the glass body has a particle size. Containing particles having a size of 0.1 microns to 50 microns, Rayleigh scattering of light incident from the side surface of the glass body, and emitting planar light from the main surface of the glass body. It is characterized (claim 1).

  The granular material of the light scattering member of the present invention is preferably any one of transparent particles, bubbles, and metal particles that reflect light.

  The transparent particles of the light scattering member of the present invention have a particle diameter of 0.1 to 50 microns and a refractive index different from that of the glass body in the range of 0.001 to 0.5. Particles or transparent resin particles are preferred (Claim 3).

  The metal particles of the light scattering member of the present invention preferably have a particle size of 0.1 to 50 microns and are contained in the glass body in a weight percentage of 0.001 to 1.0. ).

  In the light scattering member of the present invention, it is preferable that at least the main surface of the glass body opposite to the main surface that emits light is formed into a mirror surface (Claim 5), and the mirror surface is a foam sheet. The sheet surface is preferably (claim 6).

  The light scattering member of the present invention is characterized in that a clad layer having a refractive index smaller than that of the glass body is formed on at least a main surface of the glass body that emits light in the planar shape. ).

The method for producing a light scattering member of the present invention has a particle diameter of 0.1 to 50 microns on a flat substrate made of any one of a glass plate, a metal plate, and a glass plate on which a metal film is formed. A general formula containing metal particles such as metal alkoxides and metal oxides, or particles of transparent resin particles, is represented by Na ₂ O.nSiO ₂ .mH ₂ O (n and m are coefficients), and a solution layer of sodium silicate Alternatively, by forming a sol solution layer of either sodatetramethoxysilane or tetraethoxysilane, and evaporating the water in the solution layer, the substrate has translucency and contains the granular material. A flat glass body that forms the glass body that emits light incident on the side surface as planar light from the main surface by Rayleigh scattering of the granular material (claim 8). .

Method for manufacturing the light scattering member of the present invention, the transparent particles a particle size of 50 microns or less than 0.1 microns, the general formula containing one of the granulate of the metal particles in the Na 2 _{O ·} nSiO 2 · mH2O The solution layer of sodium silicate or the sol solution layer of either soda tetramethoxysilane or tetraethoxysilane is sandwiched between two glass plates and sealed in a liquid-tight manner. And forming a glass body that emits light incident on the side surface of the solution layer as planar light from the main surface through at least one of the two glass plates by Rayleigh scattering of the granular material. (Claim 9).

  The light scattering member manufacturing method of the present invention is characterized in that a resin plate having translucency is used instead of the glass plate on the light emitting side of the two glass plates. ).

  The manufacturing method of the light-scattering member of the present invention is characterized in that a metal plate serving as a mirror surface is used instead of the glass plate opposite to the light-emitting side of the two glass plates. 11).

  The method for producing a light scattering member of the present invention uses a solution layer of a water-soluble polymer such as carboxyvinyl polymer, polyvinyl alcohol, or polyacrylamide instead of the solution layer of sodium silicate and the solution layer of sol. It is characterized (claim 12).

  In the case of the light-scattering member of the present invention according to claim 1, a silicate glass body having a smaller birefringence than that of a resin and excellent in workability and flatness has a particle size of 0.1 to 50 microns. By containing the body, light incident from one side of the glass body is Rayleigh scattered by the granular body and uniformly diffused into a planar shape, and even in a large area, the planar shape is uniform from the main surface of the glass body. It is possible to form a surface light source having a uniform light amount by emitting a large amount of light. And it can form in the thin structure which is not in the past by containing the said granular material in the thin plate of a glass body. In addition, it is inexpensive because it has a glass body configuration.

  Therefore, it can be used as a backlight device for liquid crystal display devices such as liquid crystal television receivers and mobile phones, and as a surface light source device for electric display devices such as indoor and outdoor lighting devices, electric bulletin boards, electric signboards, etc. An extremely good uniform surface light source can be obtained with incident light from one side surface, and an inexpensive conventional light scattering member can be provided. The main surface from which light is emitted may be one side or both sides of the glass body.

  In the case of the light scattering member of the present invention according to claim 2, the granular material can be easily realized by any one of transparent particles, bubbles, and metal particles.

  In the case of the light scattering member of the present invention according to claim 3, the transparent particles as the granular body have a particle diameter of 0.1 to 50 microns and a refractive index of 0.001 or more with respect to the glass body. This can be realized with a specific configuration using different metal oxide particles or transparent resin particles within a range of 0.5 or less.

  In the case of the light scattering member of the present invention according to claim 4, the metal particles, which are the transparent particles as the granular material, have a particle size of 0.1 to 50 microns and a weight percentage of 0.1% on the glass body. By containing 001-1.0, the specific structure which contains the said metal particle in the said glass body can be provided.

  In the case of the light scattering member of the present invention according to claim 5, at least the main surface of the glass body opposite to the main surface that emits light is formed in a mirror surface, so that light is emitted from one surface of the glass body. In this case, there is an advantage that the light quantity of the surface light source is increased.

  In the case of the light scattering member of the present invention according to claim 6, the mirror surface can be easily realized by the sheet surface of the foam sheet.

  In the case of the light scattering member of the present invention according to claim 7, the light that radiates to the surface of the light that travels parallel to the surface that emits light due to the critical angle being increased by the cladding layer having a refractive index smaller than that of the glass body. There is an advantage that a uniform surface light source can be emitted by increasing the amount of capture or preventing light leakage due to dust or the like.

  Next, in the method for producing a light scattering member of the present invention according to claim 8, the glass plate, the metal plate, or the glass plate on which the metal film is formed has translucency on the highly planar substrate. A flat glass body containing a granular material, and the light incident on the side surface has a particle diameter of 0.1 to 50 microns and a refractive index of 0.001 or more with the glass body The light scattering member of the present invention can be manufactured by forming the glass body that emits as planar light from the main surface by Rayleigh scattering of the granular materials different in a range of 0.5 or less.

  In the case of the method for producing a light scattering member of the present invention according to claim 9, in place of the glass body, between the two glass plates, either a solution layer of sodium silicate, soda tetramethoxysilane, or tetraethoxysilane The glass body is sealed by liquid-tightly sealing the sol solution layer, and the sealed solution layer contains granular particles of either transparent particles or metal particles. It is an inexpensive structure and manufacturing method having the same planarity as (solid), and a novel light scattering member having the same effect as the light scattering member of the glass body (solid) can be manufactured.

  In the case of the method for producing a light scattering member of the present invention according to claim 10, instead of the glass plate on the side from which light is emitted (specifically, one or front glass plate) of the two glass plates, By using a resin plate having light properties, the light scattering member can be manufactured at a lighter weight and at a lower cost.

  In the case of the method for producing a light scattering member of the present invention according to claim 11, by using a metal plate serving as a mirror surface instead of the glass plate on the opposite side to the light emitting side of the two glass plates, When light is emitted from the glass plate on one side, there is an advantage that a light scattering member that increases the amount of light from the surface light source can be manufactured.

  In the method for producing a light scattering member of the present invention according to claim 12, in place of the solution layer of the sodium silicate and the solution layer of the sol, a solution layer of a water-soluble polymer such as carboxyvinyl polymer, polyvinyl alcohol, polyacrylamide or the like. Even if it uses, the light-scattering member which show | plays the same effect as the case where the solution layer of the said sodium silicate and the solution layer of the said sol can be manufactured.

It is sectional drawing of the light-scattering member of the 1st Embodiment of this invention. It is sectional drawing of the light-scattering member of the 2nd Embodiment of this invention. It is sectional drawing of an example of the light-scattering member of the 3rd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the light-scattering member of FIG. It is sectional drawing of the other example of the light-scattering member of the 3rd Embodiment of this invention. It is sectional drawing of the light-scattering member of the 4th Embodiment of this invention. It is explanatory drawing of the manufacturing method of the light-scattering member of FIG. An example of the conventional light-guide plate is shown, (a) is a perspective view, (b) is sectional drawing. It is a perspective view of the other example of the conventional light-guide plate.

  Next, in order to describe the present invention in more detail, an embodiment will be described in detail with reference to FIGS.

(First embodiment)
A first embodiment will be described with reference to FIG.

  FIG. 1 is a cross-sectional view showing a configuration of a light scattering member 1a according to the present embodiment. The light scattering member 1a is made of, for example, a thin plate-like transparent (translucent) glass body (solid) ) 2a. The glass body 2a contains the granular material 3 in a substantially uniformly dispersed state. The granular material 3 is any one of transparent particles, bubbles, and metal particles having a particle size of 0.1 to 50 microns.

  The light scattering member 1a configured as described above is uniformly distributed in the member by Rayleigh scattering of, for example, LED or LD visible light incident from one side surface 21 on the right side of the paper as shown in FIG. While spreading on the side surface 22 on the left side of the paper, the light is emitted as planar light (planar light source) from the upper and lower main surfaces 23 and 24 of the glass body 2a. As will be described later, when one of the main surfaces 23 and 24 is a mirror surface (reflection surface), the planar light is emitted from only one of the main surfaces 23 and 24.

  Here, the Rayleigh scattering will be described. Generally, when light collides with a particle having a different refractive index, the behavior varies depending on the size of the particle. When the size of the particle is equal to or greater than the wavelength of light, it is called Mie scattering, and the light collides with the particle to cause forward scattering, but the size of the particle is 10 minutes of the wavelength of the light. 1 or less to 0. In the case of several microns, Rayleigh scattering occurs. When the particle size is further reduced to about several nanometers, scattering due to birefringence occurs.

  In Rayleigh scattering, it is known that forward scattering and back scattering are caused depending on the shape, refractive index, and size of particles. The light scattering member 1a is used for the light guide plate and the surface light emitter in the edge light type backlight of the liquid crystal display device by scattering the light incident from the side surface in the lateral direction by using the forward scattering and the back scattering. it can.

  In addition, as described above, the reduction of scattering due to birefringence seen in a resin (solid) light guide plate is difficult to control because of its severe changes due to stress, etc. Glass, which is the main component of 2a, is a material having a small birefringence, its change due to stress is small, excellent in smoothness (flatness), and inexpensive.

  And the light-scattering member 1a which uses glass as a main material and generates a planar light source by using Rayleigh scattering makes the light incident from one side 21 of the glass body 2a Rayleigh-scattered by the granule 3 and is uniformly planar. Even if it is diffused and has a large area, a surface light source having a uniform and sufficient light amount can be formed by emitting light with a uniform light amount from the main surfaces 23 and 24 of the glass body 2a. Furthermore, since it is the structure which contains the granular material 3 in the thin plate of the glass body 2a, it can form in the thin structure which is not in the past. In addition, it is inexpensive because it is composed of the glass body 2a mainly composed of glass.

  Therefore, the surface of the light guide plate in the edge light type backlight device of the liquid crystal display device corresponding to the upsizing of the liquid crystal television receiver, the mobile phone, etc., and the surface of the electric display device such as an indoor or outdoor lighting device, an electric bulletin board, an electric signboard, etc. Provided is an unprecedented light scattering member 1a that can be used for a light guide or surface light emitter as a light source device, is thin, can provide a very uniform surface light source with incident light from one side surface, and is inexpensive. be able to.

  Below, the specific structural example of the glass body 2a or the granular material 3 is demonstrated.

First, the glass body 2a is made of any one of general soda glass, borate glass, lead crystal glass containing lead oxide, semi-crystal glass, potassium crystal containing potassium oxide, low melting point glass, and the like. . The low melting point glass includes ZnO—PbO—B ₂ O ₃ series, PbF ₂ —SnF ₂ —SnO—P ₂ O ₅ series, PbCl ₂ —SnCl ₂ —SnO—P ₂ O ₅ series, SnF ₂ —SnO. -P ₂ O _{5 based, SnCl 2 -SnO-P 2 O} 5 _{system, SnO-B 2 O 3 -P} 2 O 5 _{based, PbCl 2 -SnCl 2 -SnO-P} 2 O 5 system, _Ag 2 O-P ₂ O _{5 system, Bi 2 O 3 -ZnO-B} 2 O 3 _{system, SiO 2 -R 2 O-B} 2 O 3 -PbO _system, there is a SiO ₂ -B ₂ O 3 -PbO system. The glass obtained by the Si _{(OCH 3) 4} in a sol-gel method can also be utilized.

  The light emitted from the glass body 2a to the upper and lower surfaces 23 and 24 is a component perpendicular to the surfaces 23 and 24 (a component of parallel light) particularly in the case of a light guide plate of a backlight of a liquid crystal display device. It is important to include a lot. For this purpose, it is necessary to reduce the critical angle of light emitted from the glass body 2a to the upper surface. Therefore, the glass body 2a preferably has a large refractive index, and the critical angle is 41.8 degrees in the case of general soda glass (refractive index is 1.52), and that of lead glass (refractive index is 1.92). In this case, it is 31.4 degrees, and in the case of zinc oxide (refractive index is 2.1), it is 27.9 degrees. Therefore, by selecting a material having a refractive index as high as possible as the glass body 2a, most of the perpendicular light can be extracted. In some cases, a prism sheet or the like may be arranged on the surface of the glass body 2a to extract more vertical light. The glass body 2a is basically flat (thin plate), but may be a cube, or a shape close to a cylinder or a sphere, depending on the application.

  In the glass body 2a, when emitting planar light from one principal surface, at least the principal surface that is not desired to be emitted, for example, the lower surface 24, is a mirror surface or a reflective surface, as will be described later. It can be effectively released from a specific part.

  Next, as the granular material 3 contained in the glass body 2a, first, it is important to select particles having a size that causes Rayleigh scattering but does not cause birefringence. The particle size must be greater than 0.01 microns so that it does not occur. Further, in order to cause Rayleigh scattering, it is necessary that it is not more than 1/10 of the visible light wavelength of the light source, that is, not more than about 50 microns, and when the granular material 3 is transparent, It is necessary that the refractive index be different in the range of 0.001 to 0.5. In addition, when the granular material 3 is opaque, it is necessary to reflect light like a metal. Since it aims at scattering, the shape of the granular material 3 may be any shape, and is generally spherical. Moreover, the addition amount (content) of the granular material 3 is about 0.001 to 1 and 0 weight percent, so that incident light is scattered little by little and light is emitted uniformly from the surface to be emitted. However, the optimum addition amount is considered to be different depending on the use and the size of the surface, and is not limited to the above range.

  The granular material 3 that satisfies the above conditions is preferably any of the above-described transparent particles, bubbles, and metal particles that reflect light.

  The transparent particles are composed of metal oxide particles or transparent resin particles. Examples of the metal oxide particles include magnesium oxide, aluminum oxide, zinc oxide, gallium oxide, zirconium oxide, titanium monoxide, titanium dioxide, nickel oxide, and oxide. There are cerium, tungsten oxide, cerium fluoride, magnesium fluoride, and the like, and examples of the metal include gold, silver, aluminum, iron, copper, chromium, titanium, and zinc. Further, as transparent resin particles, for example, acrylic, polycarbonate, polystyrene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, triacetyl cellulose, silicone, fluororesin, polyarylate, polyethersulfone, arton, ZEONEX, etc. There are plastic, ethylene-propylene rubber, butyl rubber, isoprene rubber, butadiene rubber, acrylonitrile rubber, chloroprene rubber, styrene-butadiene rubber, silicone rubber, urethane rubber, transparent rubber such as fluorine rubber, and the like.

  In the case where the granular material 3 is a particle of the metal that reflects light, the particle size is preferably 0.1 to 50 microns, and the glass body 2 preferably contains 0.001 to 1.0 by weight percent. .

(Second Embodiment)
A second embodiment will be described with reference to FIG.

  FIG. 2 is a cross-sectional view showing the configuration of the light scattering member 1b of the present embodiment. The light scattering member 1b is different from the light scattering member 1a in the first aspect of the glass body 2a. In order to selectively emit planar light from only a certain upper surface 23, at least the lower surface 24, which is the main surface on the opposite side, preferably has a mirror surface having a reflectance of 90% or more or a fine gap having a reflectance of 90% or more. It is a point formed on the reflecting member surface formed of the sheet surface of the plastic foam sheet 4. The mirror surface is a method of vapor-depositing a metal such as silver, aluminum, titanium, zinc, or copper, a method of bonding these metal foils or plates to the glass body 3, and further depositing silver from silver nitrate like a silver mirror. It can form by the method of making it. The plastic foam sheet 4 having a fine void having a reflectance of 90% or more can be realized by a micro foam sheet such as a trade name “MCPET” manufactured by Furukawa Electric Co., Ltd., for example. In order to prevent light leakage from the side surface 22, the side surface 22 may also be formed on a mirror surface or a sheet surface. Further, the mirror surface may be provided away from the lower surface of the glass body 2a, but in this case, the efficiency of the light emitted to the upper surface 23 is lower than that provided in close contact. Therefore, in this case, it is also possible to print the reflective dots on the lower surface 24 and use the scattering system configuration together.

  The second point that the light scattering member 1b is different from the light scattering member 1a is that a clad layer 5 having a refractive index lower by 0.001 or more than the glass body 2a is provided on the upper surface 23 and the side surface 21 of the glass body 2a. is there. By providing the clad layer 5, there is an advantage that light leakage due to dust attached to the light scattering member 1 b can be prevented and a uniform surface light source can be emitted from the upper surface 23.

  As a material of the clad layer 5, a material having a low refractive index smaller than that of the glass of the glass body 2a by 0.001 or more is suitable. Specifically, a low refractive index material such as fluorinated glass, metal fluoride, or fluororesin can be used. Further, a solid material may be fired, and a foaming material or a glass balloon added with a gas having a low refractive index in the gap may be added. Specifically, sodium fluoride, magnesium fluoride, calcium fluoride, aluminum fluoride, or the like, or added to a glass material, or PFA (tetrafluoroethylene perfluoro) which is a transparent fluororesin Alkyl vinyl ether copolymer), ETFE (ethylene tetrafluoroethylene copolymer), PVF (polyvinyl fluoride film), etc., and permeable fluoro rubber may be used.

  By the way, in both the said embodiment, a cold cathode tube, LED, LD, or LD with polarization property can be utilized for the light source of the edge light system which injects light into the side surface 21 of the glass body 2a. These light sources can be similarly applied to the following embodiments. When the LD having polarization is used as the incident light source of the glass body 2a, the light scattering members 1a and 1b emit the plane light source of the polarized light. Therefore, the light guide plate of the edge light type backlight device such as a liquid crystal display device. Further, when the light scattering members 1a and 1b are used, there is an advantage that the backlight that has been wasted can be effectively used without waste by omitting the deflection filter, and the amount of light of the backlight is increased.

  Moreover, it is also possible to use organic EL for the side surface 21 (in some cases, both side surfaces 21 and 22) of the glass body 2 as the edge light type light source of FIG.

(Third embodiment)
A third embodiment will be described with reference to FIGS.

  FIG. 3 is a cross-sectional view showing the configuration of the light scattering member 1c of this embodiment. The light scattering member 1c is different from the light scattering members 1a and 1b in that a silicate glass plate, a metal plate, and a metal film are used. A flat glass body 2b having translucency and containing the granular material 3 is formed on a flat substrate 6 made of any one of the glass plates on which is formed. In addition, it is preferable that the joint surface with the glass body 2b of the board | substrate 6 is a mirror surface.

  The light scattering member 1c also uniformly scatters the light of the light source incident on one of the side surfaces 21 and 22 by Rayleigh scattering of the granular material 3 having a particle size of 0.1 to 50 microns. It can be emitted as planar light from the (main surface) 23, has the same uses as the light scattering members 1a and 1b of both the embodiments, and has the same effect.

  The light scattering member 1c is manufactured, for example, as described below.

FIG. 4 shows an outline of the manufacturing process of the light scattering member 1c. First, a thin plate-like substrate 6 is prepared by the substrate preparation process of FIG. Next, the general formula containing metal particles such as metal alkoxide and metal oxide or granular particles of transparent resin particles uniformly on the substrate 6 by the coating process of FIG. 5B is Na ₂ O · nSiO ₂ · mH. A solution layer 7 having an appropriate thickness of sodium silicate represented by ₂ O (n and m are coefficients) is formed. At that time, a frame or the like for preventing dripping is provided on the substrate 6 as necessary. Further, the substrate 6 and the solution layer 7 are heated at an appropriate temperature by the drying process shown in FIG. 5C, and the water in the solution layer 7 is evaporated, thereby forming a glass body 2b on the substrate 6 and light scattering. The member 1c is manufactured.

  The solution layer 7 may be a sol solution layer of either soda tetramethoxysilane or tetraethoxysilane used in a so-called sol-gel method. In this case, the solution layer is dried and then granulated. By uniformly adding a predetermined amount of particles 3 and further heat-treating, a glass body 2b in which the granules 3 are uniformly dispersed can be formed on the substrate 6 to manufacture the light scattering member 1c.

  And by manufacturing the light-scattering member 1c in this way, a smooth (flat) and inexpensive soda glass or the like is used as the substrate 6 to obtain a glass body 2b on which the granular bodies 3 are uniformly dispersed. The light scattering member 1c can be manufactured inexpensively and easily. At that time, instead of the soda glass substrate 6 whose upper surface is processed into a mirror surface, soda glass on which a metal film such as aluminum serving as a mirror surface is deposited, or soda glass having a metal thin film on the upper surface is used as the substrate 6. Also good.

  FIG. 5 is a cross-sectional view of a light scattering member 1 d manufactured using soda glass 62 on which a metal film 61 such as aluminum is deposited as the substrate 6.

  In addition, for manufacturing the glass bodies 2a and 2b, a float method, a roll-out method, a pulling method, a fusion method, or the like known as a glass manufacturing method may be used. Moreover, the granular material 3 may be added to soda glass or the like as a raw material from the beginning. After the raw material is processed into the shape of the glass bodies 2a and 2b, it is heated again to be softened and added. May be.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS.

FIG. 6 is a cross-sectional view showing the configuration of the light scattering member 1e of the present embodiment. The light scattering member 1e has, for example, a general formula containing the granular material 3 represented by Na ₂ O · nSiO ₂ · mH ₂ O. (N and m are coefficients). A solution layer 8 of sodium silicate is sandwiched between two glass plates 9a and 9b and sealed in a liquid-tight manner. In addition, since it is difficult to seal a solution and to disperse | distribute a bubble stably and uniformly in it, the granule 3 of this embodiment does not contain a bubble.

  The light scattering member 1e can also generate a planar light source from at least one of the glass plates 9a and 9b from the main surface (upper or lower surface) of the solution layer 8 using Rayleigh scattering. . At that time, the solution layer 8 does not have scattering due to birefringence seen in a resin (solid) light guide plate, and the solution layer 8 has excellent smoothness (flatness) and is inexpensive. Therefore, the light scattering member 1e can obtain the same effects as the light scattering members 1a to 1d of the above embodiments.

  By the way, the light scattering member 1e is manufactured as described below, for example.

  FIG. 7 shows an outline of the manufacturing process of the light scattering member 1e. First, two glass plates 9a and 9b made of, for example, silicate glass are arranged in parallel at a predetermined interval by the preparation process of FIG. Except for the upper surface of the peripheral portion, the both side surfaces and the bottom surface are liquid-tightly sealed with an appropriate sealing material 10 to form a thin box. Next, by the filling step shown in FIG. 5B, the solution of the general formula sodium silicate containing the granular material 3 is poured into the box from the upper opening, and the solution layer 8 is placed between the glass plates 9a and 9b. Form. Furthermore, the upper part of the said box is sealed with the sealing material 10 by the sealing process of the figure (c), and it seals liquid-tightly, and the light-scattering member 1e is manufactured.

  The solution layer 8 may also be a sol solution layer of either soda tetramethoxysilane or tetraethoxysilane used in a so-called sol-gel method.

  Further, a glass plate on the side of emitting light among the glass plates 9a and 9b, in the case of FIG. 6, a resin plate having translucency may be used instead of the glass plate 9a. When light is emitted from both the upper and lower surfaces, both the glass plates 9a and 9b may be replaced with a resin plate having translucency. By doing so, there is an advantage that the cost is further reduced. In addition, it is preferable to replace the glass plate 9b on the side opposite to the glass plate 9a that emits light with a metal plate that is a mirror surface to improve the reflection performance.

  The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit thereof. For example, the case of the fourth embodiment A solution layer of water-soluble polymer such as carboxyvinyl polymer, polyvinyl alcohol, polyacrylamide, etc. is used in place of the sol solution layer of acid soda solution layer 8 or soda tetramethoxysilane or tetraethoxysilane, which is more inexpensive. You may form in.

  Sodium silicate solution layer 8, soda tetramethoxysilane, tetraethoxysilane sol solution layer, water-soluble polymer solution layer such as carboxyvinyl polymer, polyvinyl alcohol, polyacrylamide and the like have high viscosity, and granular material 3 This is advantageous for the uniform dispersion of and the stabilization of the dispersion state. In addition, an appropriate dispersant, compatibilizer, emulsifier, and the like can be added to the solution layers 7 and 8 in order to positively achieve uniform dispersion of the granular material 3 and stabilization of the dispersed state. Furthermore, the surface of the granular material 3 can be uniformly dispersed and the dispersed state can be stabilized by chemical treatment, coupling agent treatment, or the like.

  Further, specific examples of the glass bodies 2a, 2b, the granular body 3, the cladding layer 5, the solution layers 7, 8 and the like are not limited to those shown in each of the above embodiments, and do not depart from the spirit of the present invention. It may be anything.

  Next, the light scattering members 1a to 1e, the glass bodies 2a, 2b, etc. may have any thickness, planar dimensions, planar shape, etc., such as a backlight device, an indoor / outdoor lighting device, an electric bulletin board, and an electric signboard. Of course, it may be set appropriately according to the size and shape of the surface light source required by the electro-optical display device.

  And the light-scattering members 1a-1e of this invention become a surface light source device of electroluminescent display apparatuses, such as a light-guide plate in various edge light system backlight apparatuses, an indoor and outdoor illuminating device, an electric bulletin board, and an electric signboard. It can be used for a light guide or a surface light emitter.

DESCRIPTION OF SYMBOLS 1a-1e Light-scattering member 2a, 2b Glass body 3 Granule 4 Plastic foam sheet 5 Cladding layer 7, 8 Solution layer 9a, 9b Glass plate

Claims (12)

With a silicate glass body,
The glass body includes a granular body having a particle size of 0.1 to 50 microns,
A light scattering member, wherein light incident from a side surface of the glass body is Rayleigh scattered by the granular body, and planar light is emitted from a main surface of the glass body. The light scattering member according to claim 1,
The granular material is any one of transparent particles, bubbles, and metal particles. The light scattering member according to claim 2,
The transparent particles are metal oxide particles or transparent resin particles having a particle size of 0.1 to 50 microns and a refractive index different from the glass body in a range of 0.001 to 0.5. A light scattering member. The light scattering member according to claim 2,
The light scattering member, wherein the metal particles have a particle size of 0.1 to 50 microns and are contained in the glass body in a weight percentage of 0.001 to 1.0. In the light-scattering member in any one of Claims 1-4,
The light scattering member, wherein a main surface opposite to a main surface that emits light in the planar shape of the glass body is formed as a mirror surface. The light scattering member according to claim 5,
The light scattering member, wherein the mirror surface is a sheet surface of a foam sheet. In the light-scattering member in any one of Claims 1-6,
A light scattering member, wherein a clad layer having a refractive index smaller than that of the glass body is formed on at least the main surface of the glass body that emits light in the planar shape. Metal particles such as metal alkoxide and metal oxide having a particle size of 0.1 to 50 microns on a flat substrate made of any one of a glass plate, a metal plate, and a glass plate on which a metal film is formed. Or the general formula containing the granular body of transparent resin particles is represented by Na ₂ O · nSiO ₂ · mH ₂ O (n and m are coefficients), a solution layer of sodium silicate, soda tetramethoxysilane, tetraethoxysilane Forming a solution layer of any of the sols,
By evaporating the water in the solution layer, a light-transmitting plate-like glass body containing the granular material on the substrate is used. A method for producing a light scattering member, comprising: forming the glass body that emits as planar light from a main surface by scattering. A general formula containing any one of transparent particles having a particle size of 0.1 to 50 microns and metal particles is represented by Na ₂ O.nSiO ₂ .mH ₂ O (n and m are coefficients). A sodium silicate solution layer or a soda tetramethoxysilane or tetraethoxysilane sol solution layer was sandwiched between two glass plates and sealed in a liquid-tight manner, and incident on the side surface of the solution layer. A method for producing a light scattering member, comprising: forming a glass body that emits light as planar light from at least one of both glass plates by Rayleigh scattering of the granular material. In the manufacturing method of the light-scattering member of Claim 9,
A method for producing a light scattering member, wherein a light-transmitting resin plate is used in place of the light-emitting glass plate of the two glass plates. In the manufacturing method of the light-scattering member of Claim 9 or 10,
A method for producing a light scattering member, wherein a metal plate serving as a mirror surface is used instead of the glass plate on the opposite side to the light emitting side of the two glass plates. In the manufacturing method of the light-scattering member in any one of Claims 9-11,
A method for producing a light scattering member, wherein a solution layer of a water-soluble polymer such as carboxyvinyl polymer, polyvinyl alcohol, polyacrylamide, or the like is used instead of the solution layer of sodium silicate and the solution layer of sol.

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