JPH11316307A - Reflector - Google Patents

Abstract

(57) [Summary] Reflector 1 having higher reflectivity than conventional reflector
It is to provide. SOLUTION: A reflector 1 is provided with a reflection layer 2 formed containing zinc oxide on an outer surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflector for reflecting a light beam so as to guide it to a member to be illuminated in an apparatus requiring illumination by a light source.

[0002]

2. Description of the Related Art In a device provided with an illuminated member that needs to be illuminated at a certain illuminance, when it is not possible to make a light beam emitted from a light source directly enter the illuminated member due to the structure of each member of the device. In general, a reflector for reflecting light so as to guide the light to the illuminated member is incorporated.

For example, as an example of a liquid crystal display device, a screen of a liquid crystal display device as a member to be illuminated (hereinafter, abbreviated as “liquid crystal screen”) receives light from the back side thereof. The fluorescent lamp as a light source is disposed at a fixed position in the lateral direction with respect to the liquid crystal screen on the back side of the liquid crystal screen. A light guide plate is provided on the back side of the liquid crystal screen, and a fluorescent lamp is provided outside a lateral end of the light guide plate. Then, the light beam that has entered the light guide plate from the fluorescent lamp is guided to the front side of the light guide plate (the direction side of the liquid crystal screen) and enters the liquid crystal screen.

[0004] Here, a reflector is provided on the back side of the light guide plate, and light rays are reflected by the reflector, so that light rays incident on the light guide plate are further guided to the liquid crystal screen, and The screen is displayed clearly.

[0005] Such reflectors have been formed containing calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ) or titanium oxide (TiO ₂ ).

[0006]

However, since the reflectivity of the conventional reflector is not always high, it is difficult to reflect the light emitted from the light source to the member to be illuminated. As a result, light was lost and the illuminated member could not be efficiently illuminated.

[0007] Therefore, an object of the present invention is to provide a reflector having a higher reflectivity than a conventional reflector.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, the reflector of the present invention is provided with a reflection layer formed containing zinc oxide particles on its outer surface (claim 1).

As a result, the reflectance can be increased as compared with a conventional reflector formed by containing calcium carbonate or the like.

When the zinc oxide particles are hollow particles (claim 2), diffuse reflection is caused by the surface and the inner wall surface of the particles, so that the reflectance can be further increased.

Further, when the hollow particles are formed so that the ratio of the average diameter of the hollow portion to the average particle diameter is 0.1 or more and 0.9 or less (claim 3), the reflectance is particularly improved. Can be higher.

Further, when fine grooves are formed on the surface of the particles (claim 4), diffuse reflection occurs on the surface of the particles, so that the reflectance can be further increased.

When the reflector is provided with a primer layer provided adjacent to the inside of the reflection layer (claim 5), the adhesion is increased and zinc oxide contained in the primer layer is provided. By increasing the hiding power by the fine particles, the reflectance can be further increased.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a reflector according to the present invention will be described below with reference to FIGS.

First, a reflector 1 according to a first embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a sectional view of the reflector 1.

In the reflector 1 shown in FIG. 1, the upper end 1a of the reflector 1 corresponds to the outer surface on which light rays are incident, and the lower part thereof corresponds to the inside.

The reflector 1 is composed of a reflective layer 2 and a substrate 3.

The reflection layer 2 is formed to include zinc oxide (ZnO ₂ ) and a general reflection coating agent comprising a resin binder and a reflection agent.

The substrate 3 is formed to contain foamed polyethylene terephthalate (foamed PET) or white PET.

This reflector 1 has a reflection layer 2 containing zinc oxide.
Therefore, the reflectance is higher than that of a conventional reflector formed of calcium carbonate or the like.

Here, when the zinc oxide particles contained in the reflection layer 2 are hollow particles as shown in FIG. 2, the reflectance of the reflector 1 can be further increased.

FIG. 2 shows the shape of the hollow particles.

As shown in FIG. 2, a hollow portion 6a is formed in the zinc oxide particle 6 having a substantially spherical shape. According to such hollow particles, since diffuse reflection is caused by the surface and the inner wall surface of the particles, the reflectance can be increased.

With respect to such hollow particles, it is particularly preferable that the ratio of the average diameter h of the hollow portion to the average particle diameter D be 0.1 or more and 0.9 or less in order to increase the reflectance. On the other hand, if the ratio of the average diameter h of the hollow portion to the average particle size D is less than 0.1, the diffusion by the hollow portion is weak, and if it exceeds 0.9, it is difficult to form hollow particles.

As shown in FIG. 2, when the fine grooves 6b are formed on the surface, the reflectance can be further increased. Since the minute grooves 6b cause diffuse reflection, the reflectance can be increased.

Although an example in which the fine grooves 6b are formed in the hollow particles 6 is shown in FIG. 2, it is also possible to increase the reflectivity of fine particles formed of zinc oxide particles in which the hollow portions 6a are not formed. Can be.

Next, a reflector 11 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a sectional view of the reflector 11.

The reflector 11 includes, in addition to the reflective layer 2 and the base material 3, a primer layer 12 interposed between these members.
It is comprised including.

The primer layer 12 can be formed containing hollow zinc oxide fine particles.

According to the reflector 11, since the reflector 11 is provided with the primer layer 12, and the light concealing property is increased, the reflectance can be further increased.

Next, a reflector 21 according to a third embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a sectional view of the reflector 21.

As shown in FIG. 4, the reflector 21 includes a first reflecting layer 2a, a substrate 3, and a first primer layer 12a interposed between these members. Second primer layer 12b and second reflective layer 2b inside thereof
And is provided.

According to the reflector 21 configured as described above, since the light concealing property is further increased, the reflectance can be further increased.

Next, an example of a method for manufacturing the reflector having the above-described configuration will be described.

When the reflector 1 is manufactured, first, a reflector necessary for forming the reflection layer 2 is adjusted as follows.

As a general reflection coating agent, for example, powdery zinc oxide particles, titanium oxide, aluminum oxide particles and the like are dispersed in a coating agent comprising an acrylic binder or a urethane binder.

When the zinc oxide particles are formed into hollow particles by a method such as suspension polymerization, emulsion polymerization, or sol-gel method, fine grooves can be formed with the formation of such hollow particles. .

The reflecting agent thus adjusted was applied to the substrate 3
When the coating is applied to the outer surface and dried, the reflector 1 having the reflecting layer 2 formed on the outer surface can be obtained.

Next, when manufacturing the reflector 11, a raw material liquid necessary for forming the primer layer 12 is prepared. Such a raw material liquid is prepared by dispersing the hollow zinc oxide according to the present invention in an acrylic binder. Then, the primer layer 12 is formed by applying the raw material liquid of the primer layer 12 to the surface of the base material 3 and drying it. Next, the reflective agent used to form the reflective layer 2 is applied to the surface of the primer layer 12 and dried to form the reflective layer 2. Thereby, the reflector 11 can be obtained.

Next, a specific application example of the above reflector will be described with reference to the reflector 1 as an example.

FIG. 5 is a sectional view of a constituent member of a backlight unit 50 of a liquid crystal display device in which the reflector 1 is incorporated. In FIG. 5, the upper side is the front side, that is, the liquid crystal screen side, and the lower side is the back side.

As shown in FIG. 5, a fluorescent lamp 51 as a light source is disposed along the front-rear direction A,
2 is arranged such that the fluorescent lamp 51 is located outside the left end in the left-right direction B. Further, in the vertical direction C, the diffusion sheet 53 is disposed above the light guide plate 52,
The prism sheet 54 is disposed above the diffusion sheet 53. The reflector 1 is incorporated along the lower surface of the light guide plate 52.

In this backlight unit 50,
The light emitted from the fluorescent lamp 51 is guided from the light guide plate 52 to the diffusion sheet 53, further guided to the prism sheet 54, and then enters the upper liquid crystal screen (not shown).

When the light beam is guided to the liquid crystal screen through each of the above members, the light beam L that travels inside the light guide plate 52 toward the lower surface of the light guide plate 52 among the light beams that have entered the light guide plate 52 from the fluorescent lamp 51 is as described above. The light is reflected by the reflector 1 and is guided above the light guide plate 52. According to the light guide plate 52 in which the reflector 1 according to the present invention is incorporated, a larger portion of the light emitted from the fluorescent lamp 51 is made to enter the liquid crystal screen than in the light guide plate in which the conventional reflector is provided. Therefore, the liquid crystal screen can be clearly displayed.

In each of the above embodiments, an example in which the outer surface of the reflector is formed in a planar shape has been described. However, the reflector may be formed in a curved shape or a spherical shape. It is only necessary that the reflective layer is formed on the outer surface where the light enters.

[0047]

An embodiment of the present invention will be described with reference to FIG.

FIG. 6 shows the results of measuring the spectral reflectance characteristics of three types of samples.

In FIG. 6, the horizontal axis represents the wavelength of the irradiated light, and the vertical axis represents the reflectance (%) expressed as a percentage.

The characteristics are the spectral reflectance characteristics of the sample I of the embodiment. The characteristics are the spectral reflectance characteristics of the sample II to be compared, and the characteristics are the spectral reflectance characteristics of the sample III to be compared.

Samples I, II, and III were configured as follows.

1. Sample I Like the reflector 1, the sample I was composed of the reflective layer 2 and the base material 3.

The reflection layer 2 was formed by including hollow particles of zinc oxide having fine grooves formed on the surface and a general reflection coating agent, and the thickness was 25 μm. The substrate 3 was formed of white PET, and its thickness was 75 μm. Then, the thickness of the sample I was set to 100 μm.

Table 1 shows the physical properties of the zinc oxide hollow particles used to form Sample I.

[0055]

[Table 1]

According to the true specific gravity and the bulk specific gravity shown in Table 1, the ratio of the average diameter of the hollow portion to the average particle size of the used hollow particles is distributed in the range of 0.1 to 0.9.

In the specific surface area term in Table 1, the theoretical surface area means the surface area of a true sphere having the same diameter as the particle.
It means that there are many fine grooves formed on the surface of the particles corresponding to the value of the specific surface area.

2. Sample II A reflective layer was formed with a general reflective coating agent,
The thickness was 25 μm. The substrate was the same as Sample I. Then, the thickness of the sample II was set to 100 μm.

3. Sample III A white PET substrate alone was used, and its thickness was 100 μm.

Comparing the reflectances of the above samples, it can be seen from FIG. 6 that the reflectance of the sample I is the highest in most of the visible wavelength range of 410 nm to 800 nm.

[0061]

As described above, according to the reflectors of the first to third aspects, there is an effect that a higher reflectance can be obtained as compared with the conventional reflector.

According to the invention of claim 4, there is an effect that the reflectance of the reflector can be particularly increased.

The same effect can be obtained with the invention described in claim 5.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a reflector according to a first embodiment.

FIG. 2 is a view showing the shape of a hollow particle.

FIG. 3 is a cross-sectional view of a reflector according to a second embodiment.

FIG. 4 is a cross-sectional view of a reflector according to a third embodiment.

FIG. 5 is a cross-sectional view of a backlight unit incorporating a reflector.

FIG. 6 is a diagram showing a measurement result of a spectral reflectance characteristic of a reflector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reflector (1st embodiment) 2 Reflective layer 2a 1st reflective layer 2b 2nd reflective layer 3 Base material 6 Hollow particle 6a Hollow part 11 Reflector (2nd embodiment) 12 Primer layer 12a First primer layer 12b Two primer layers 21 Reflector (third embodiment) 50 Backlight unit 51 Fluorescent lamp 52 Light guide plate 53 Diffusion sheet 54 Prism sheet

[Procedure amendment]

[Submission date] March 19, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

Means for Solving the Problems To solve the above problems,
Therefore, the reflector of the present invention includes hollow zinc oxide particles.
The reflection layer to be formed is provided on the outer surface.
1).

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

Thus, the reflector is made of hollow zinc oxide particles.
Containing calcium carbonate etc.
The reflectance can be higher than that of a conventional reflector. Also grain
Can cause diffuse reflection by the surface of the particles and the inner walls of the particles.
Thus, the reflectance can be further increased.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

The average of the hollow zinc oxide particles is
The ratio of the average diameter of the hollow portion to the particle size is 0.1 to 0.9.
By setting the following (claim 2), the reflectance can be particularly increased.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

Further , the hollow zinc oxide particles are
A fine groove is formed on the surface and the specific surface area is 5 m ² / g or more and 50 m ²
/ G or less.
3). This makes the diffuse reflection on the particle surface
Increase the reflectivity.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

In addition, a press formed adjacent to the reflective layer
A primer layer is provided with zinc oxide particles.
It can be formed to include (claim 4). This
Increases the adhesion of the primer layer,
-Increasing concealment by the fine particles of zinc oxide contained in the layer
By doing so, the reflectance can be further increased.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

[0013] In addition, the oxide layer contained in the primer layer
Lead particles can be hollow zinc oxide particles
(Claim 5).

Claims (5)

[Claims] 1. A reflector comprising an outer surface provided with a reflective layer formed by containing zinc oxide particles. 2. The reflector according to claim 1, wherein the zinc oxide particles are hollow particles. 3. The ratio of the average diameter of the hollow portion to the average particle size of the hollow particles is 0.1 or more and 0.9 or less.
The reflector as described. 4. The reflector according to claim 1, wherein fine grooves are formed on the surface of the particles. 5. The reflector according to claim 1, further comprising a primer layer formed adjacent to the reflection layer.