JPH10221512A - Reflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a possibility of inducing electrical fault phenomena to fluorescent tubes, electric appliances, or electronic apparatuses positioned in the adjacent to a reflector and improve the reflectance by providing a number of metal thin films by being mutually divided into parts. SOLUTION: In a reflector covered with metal thin films 7 for improving reflectance on a base plate 6 of electrical insulating materials, a lot of metal thin films 7 are provided by mutually divided into parts. The metal thin films 7 which are composed of the electrical insulating materials such as synthetic resin, glass, and ceramics and are provided on one surface of the base plate for improving the reflectance are provided by electrically conductively divided into parts mutually so that the reflector does not reduce the reflecting light quantity so much compared with a case where metal thin films 7 are continuously provided on its whole face, and the charge generated on one surface of the electrical insulating materials is prevented from being accumulated so much. If the accumulated charge is discharged, no large discharging energy is discharged at once so as to prevent harmful phenomena from being induced to the surrounding appliances.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflector for a backlight for a direct-view type liquid crystal display device, a traffic-related signboard or a publicity notice board, and a reflector such as a reflector for lighting equipment.

[0002]

2. Description of the Related Art For example, in the case of a reflector used for a backlight of a direct-view type liquid crystal display device, a synthetic resin is used in place of a metal because of moldability, lightness, and, in some cases, ease of irregular reflection treatment. Materials, glass materials, ceramic materials, or coatings or thin plates of those materials are often used as substrates. In addition, a metal thin film of Al, Ag, or the like may be deposited on the substrate surface of such an electrically insulating material by vapor deposition or the like in order to improve the reflection efficiency. When a navigation device including a backlight unit having a reflector made of an electrically insulating material on which such a metal thin film is applied is mounted on a moving object such as an automobile, the backlight unit emits fluorescent light. It has been found that a flicker phenomenon occurs in the discharge tube. Such a phenomenon occurs when a member made of an electrically insulating material having such a metal thin film or a metal plate adhered thereto or carried thereon is used, for example, when mounted in a moving body such as an automobile or the like. As a result, static electricity is generated on the surface of the member made of the above-mentioned electrically insulating material, and the charges due to the generated static electricity are gradually accumulated in the metal thin film or metal plate. In the case where a capacitor is formed with another metallic member through the member made of a material, a large amount of electric charge is particularly accumulated. This is considered to be a failure phenomenon of electrical or electronic equipment due to electrical or radio waves caused by discharge of the accumulated charge.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a reflector in which a metal thin film for improving the reflection efficiency is applied to the surface of a substrate made of an electrically insulating material. It is an object of the present invention to provide an electric device or an electronic device that has a low possibility of causing a failure phenomenon in an electric device and has a high reflectance.

[0004]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a reflector plate comprising a substrate made of an electrically insulating material coated with a metal thin film for improving reflection efficiency. In the attached reflector, a large number of metal thin films are provided so as to be separated from each other.

As described above, a large number of metal thin films provided on one surface of a substrate made of an electrically insulating material such as synthetic resin, glass, ceramics, etc. for improving the reflection efficiency are provided by being electrically conductively separated from each other. Compared to a case where a metal thin film is continuously provided on the entire surface, a large amount of electric charges generated on a part of the surface of the electrically insulating material are accumulated in the metal thin film without significantly reducing the amount of reflected light. In addition, even if the stored electric charge is discharged, a large amount of energy is not released at once, so that there is less possibility of causing an electric harmful phenomenon to surrounding electric or electronic devices.

According to a second aspect of the present invention, there is provided a reflector according to the first aspect, wherein at least a part of the substrate surface is formed as a rough surface having minute irregularities, whereby a diffusely reflecting surface is provided. Is provided. As described above, at least a part of the substrate surface of the electrically insulating material is formed on a rough surface having minute irregularities, and a metal thin film is applied to the rough surface to form a diffuse reflection surface. Surface light source can be obtained.

According to a third aspect of the present invention, there is provided a reflector according to the first or second aspect, wherein a fluorescent discharge tube is disposed adjacent to the reflector to form a reflector of the fluorescent tube. It is characterized by. With this configuration, a flicker phenomenon of the fluorescent discharge tube as a light source provided in the vicinity is prevented, and for example, a liquid crystal display device including a backlight unit including the reflector and the fluorescent discharge tube is stable and easy to see. Display screen can be given.

[0008]

1 to 5 show a reflector for a direct-type backlight unit of a direct-view liquid crystal display device of a navigation device according to one embodiment of the present invention. FIG. 1 is a partially cutaway side view of the liquid crystal display device, and FIG. 2 is a partially cutaway top view of the backlight unit of the liquid crystal display device.
(A) is a reflection plate of the backlight unit of FIG.
FIG. 3 (b) is a top view of FIG. 3 (a), FIG. 4 is a diagram schematically showing a partially enlarged cross section of the substrate of the reflector, and FIG. FIG. 4 is a further enlarged view of the upper surface of the reflection plate of FIG.

The direct-view liquid crystal display device 1 includes a liquid crystal display element 2
And a direct-type backlight unit 3 on the back surface. The direct-type backlight unit 3 includes two fluorescent discharge tubes 4, 4 and a reflector 5 disposed behind them. In this case, the synthetic resin substrate 6 of the reflection plate 5 has U
Two semi-cylindrical reflecting surfaces 61 formed long in a letter shape are formed, and each fluorescent discharge tube 4 is held along each semi-cylindrical reflecting surface 61 such that about half thereof is buried.
Further, between each semi-cylindrical reflecting surface 61, an inclined reflecting surface 62 inclined in a mountain shape is formed.

On the surface of the inclined reflecting surface 62, glass beads having a predetermined average particle size (for example, about 20 μm) are previously applied to the surface of the substrate 6 together with a resin serving as a binder, and then solidified. As shown, a rough surface having a convex portion 6a... Having a spherical shape substantially along a part of the bead spherical surface and a concave portion 6b... Formed between the convex portions 6a is formed.

On the surfaces of the semi-cylindrical reflection surface 61 and the inclined reflection surface 62, as shown in FIG. 3, a large number of Al metal thin films 7 formed in accordance with the present invention are provided. .. Are formed. Here, as shown in FIG. 5 in a further enlarged manner, the divided portion has a width of approximately 60 to 70 μm, and each of the metal thin films 7 and
7 are formed in a grid pattern in which the vertical and horizontal width dimensions are approximately 1 mm.

On the front surface of the reflecting plate 5 provided with the fluorescent discharge tube 4, a first scattered light transmitting plate 8 formed by forming a rough surface of a transparent resin plate is superposed. The unevenness of the rough surface of the scattered light transmitting plate 8 immediately above the fluorescent discharge tube 4 is formed to be particularly large unevenness, so that the brightness of the fluorescent discharge tube 4 is suppressed from being directly transmitted. . On the front side of the first scattered light-transmitting plate 8, a second scattered light-transmitting plate 9, in which the surface of the transparent resin plate is also formed with a rough surface having minute irregularities, is superposed at a slight interval. Finally, a bright uniform surface light source is formed.

In the reflector of the above embodiment, the glossy metal thin film deposited on the surface of the reflector is composed of a large number of metal thin films which are separated from each other. Since the reflection efficiency is only over 10% of the total area of the reflection surface, the reflection efficiency is almost the same as when a metal thin film is entirely deposited, and a large amount of electric charge is hardly accumulated in the metal thin film. This does not cause a large amount of the discharged charges to be released at a time, so that an electric trouble such as a flicker of the fluorescent discharge tube arranged in the vicinity does not occur.

The formation of a large number of mutually thin metal thin films 7, 7,... On the surface of the substrate 6 can be performed, for example, as follows. The minute projections 6a
.. And the concave reflecting surface 62 having the concave portions 6b between the convex portions 6a will be described with reference to FIG. Irregularities formed at a thickness of about 10 ^-4 about μm thin film of Al 7 'the surface, for example, vacuum deposition of the substrate 6 with (FIG. 6 (b)). Next, a photoresist 10 (for example, as a positive resist, L
An organic compound (ortho naphthoquinone azide) used for the production of SI is applied to the required surface portion including the above-mentioned Al thin film 7 ', and a predetermined dividing pattern, here, the dividing pattern 11a of the above-mentioned checkerboard is photographed in almost full scale. Negative film 1
1 and light is applied from above (FIG. 6 (b)). The photoresist at the part to be divided which was exposed to light was washed out with a solvent to expose the Al thin film 7 'at the part (FIG. 6).
(C)). Next, after the exposed Al thin film portion is removed by etching treatment with a suitable etching solution such as hydrofluoric acid, the remaining photoresist is entirely exposed and removed (FIG. 6D). A large number of metal thin films 7, 7 thus divided in a predetermined dividing state as shown in FIG.
Are obtained.

In the reflecting plate of the above embodiment, glass beads or alumina having a predetermined average particle size are used to form a rough surface having minute irregularities to provide a diffusely reflecting surface. Although a method of applying fine powder such as beads together with a binder was used, other scattering treatment methods such as a roughening method by sandblasting can be used without being limited thereto, and the rough surface is, for example, as shown in FIG. As schematically shown, a rough surface having minute and completely irregular irregularities may be used.

In the reflector of the above embodiment, a large number of metal thin films formed on the substrate made of an electrically insulating material and electrically separated from each other are formed by the etching method. Applicable. For example, in the process of depositing a metal thin film such as a chemical plating process, the deposition time is reduced, or further heat treatment is applied to imperfectly adhere, resulting in a myriad of island-like metal films separated from each other. It may be formed. Alternatively, the metal thin film once formed on the entire surface may be partially removed by grinding or the like to obtain a predetermined divided state,
Alternatively, it may be obtained by forming a large number of metal thin films of a predetermined shape mutually separated on a transfer paper in advance, and transferring this to a predetermined substrate surface.

The reflector of the above embodiment is a reflector of a direct type backlight unit in a direct-view type liquid crystal display device of a navigation device of an automobile, but is a case of a peripheral type backlight unit, that is, a fluorescent discharge tube. Are provided along two or more opposing sides of the four peripheral portions of the transparent light guide plate and along the main surface (back surface) of the light guide plate opposite to the main surface on which the liquid crystal element is arranged. In the case of a backlight unit of a type in which a reflector is provided, the reflector of the present invention is also applied to the reflector provided at a distance behind the fluorescent discharge tube of the peripheral backlight unit. It goes without saying that you can do it. In addition, when it is installed on a place where static electricity is easily generated or is likely to be generated, such as a car, for example, on a moving body, a reflector for a backlight such as a traffic sign board or a publicity notice board or a reflector for a lighting device. The reflection plate of the present invention can be applied to a plate. Further, even when the fluorescent discharge tube is not mounted in the vicinity, the reflecting plate of the present invention is also used when electrical equipment or electronic equipment is arranged close to and it is desired to prevent the occurrence of an electrical failure phenomenon in those equipment. Can be applied.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of a direct-view type liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a perspective view of the backlight unit of the liquid crystal display device.
FIG. 3 is a top view partially broken away.

FIG. 3A is an enlarged view of the reflector of the backlight unit as viewed from the direction of arrows AA, and FIG. 3B is a top view of FIG.

FIG. 4 is a diagram schematically showing a partially enlarged cross section of a substrate of the reflection plate.

FIG. 5 is an enlarged view of the upper surface of the reflector.

FIG. 6 is a view for explaining an example of a method of forming a large number of mutually divided metal thin films according to the present invention on the surface of a substrate made of an electrically insulating material; It is a cross-sectional view of a state where a metal thin film is applied to the surface of
(B) is a view showing a state in which after a photoresist coating film is further formed on the metal thin film adhered to the substrate surface, exposure is performed through a negative film in which the divided pattern is copied to the original size. FIG. 3D is a view showing a state after the exposed portion of the photoresist coating film is washed out with a solution, and FIG. 4D is a diagram showing a state in which the exposed metal thin film portion is etched with a corrosive solution and then the photoresist is entirely removed. The completed state after exposure and removal is shown.

FIG. 7 is a diagram schematically showing a partially enlarged cross section of a substrate of a reflector of another embodiment different from the substrate of the reflector of the above embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device 2 ... Liquid crystal display element 3 ... Backlight unit 4 ... Fluorescent discharge tube of backlight unit 5 ... Reflector plate of backlight unit 6, 16 ... Substrate 7 ... Many metal thin films divided | segmented mutually

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // F21V 8/00 601 F21V 8/00 601F

Claims (3)

[Claims] 1. A reflection plate comprising a substrate made of an electrically insulating material coated with a metal thin film for improving reflection efficiency, wherein a large number of metal thin films are provided so as to be separated from each other. 2. The reflector according to claim 1, wherein at least a part of the surface of the substrate is formed as a rough surface having minute irregularities to provide a diffusely reflecting surface. 3. The reflector according to claim 1, wherein a fluorescent discharge tube is disposed adjacent to the reflector to form a reflector of the fluorescent discharge tube.