JPS6046503A - Diffusion plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Object of the Invention) The present invention relates to a diffuser plate that has high light transmittance and low see-through (light source transparency), and is used as a transparent screen, lighting cover, etc. be.

(Prior art) Diffusion plates used as lighting covers, display devices, rear projection screens, etc., have a method of providing fine irregularities on the surface or coating a diffusion agent layer in order to obtain uniform diffusion properties. It can be manufactured by a method of forming a base material, or by a method of dispersing a diffusing agent in a base material. The latter two methods, that is, the method using a diffusing agent, are widely used because they can be selected from among diffusing agents with various performances, can be manufactured consistently, and have high production efficiency.

Incidentally, as such a diffusing agent, various materials such as silicon ethyl oxide, barium sulfate, and glass particles have conventionally been used. For example, examples using silicon oxide include Utility Model Publication No. 29-7440 and Japanese Patent Publication No. 51-367.
Publication No. 79, Japanese Patent Publication No. 52-20857, Japanese Unexamined Patent Publication No. 52-2085
3-110826, JP-A-54-155244, JP-A-57-5742, etc. are known, and among this type of diffusing agent, silicon oxide has a high diffusivity. Frequently used as a substance that exhibits total light transmittance.
ing. However, since silicon oxide has a high hardness of 7, the saw is severely worn when cutting the diffuser plate containing silicon oxide, so the saw must be replaced frequently, and the molding material containing silicon oxide must be extruded. There are problems in manufacturing and processing, such as easy wear of screws when molding and manufacturing a diffuser plate, and wear and tear on the doctor knife used when applying paint containing silicon oxide. Ta.

The present inventor has already proposed the use of muscovite of a specific particle size as a diffusing agent, and although this muscovite has slightly lower total light transmittance than silicon oxide, it has the property of being bright and having excellent diffusivity. have. Moreover, this muscovite has a hardness of 2.5
~3, it is soft, so it is advantageous to use it together with the silicon oxide mentioned above to keep the amount added low.Furthermore, even if a small amount of muscovite is used, there is little see-through, so mixing the two is a good idea because of the balance. It has been found that this method is extremely effective for obtaining a diffuser plate.

(Objective of the Invention) Based on the above study results, the present invention has been developed to provide excellent diffusion characteristics and brightness that suppress see-through by using a mixture of silicon oxide and muscovite of a specific particle size, and at the same time improve processability. This is intended to provide an enhanced diffusion plate.

(Structure of the Invention) That is, the gist of the present invention is that the average particle size is 1 to 1
The diffusion plate is characterized in that silicon oxide of 0 μm and muscovite of average particle size of 15 to 40 μm are added in an opening that does not cause see-through.

Hereinafter, the present invention will be explained according to examples.

Silicon oxide (S102) with an average particle size of 6μ and a refractive index of 1.46.
) and a refractive index of 1155 to 1.5 with an average particle size of 15 to 35μ.
9 Muscovite (KAlz (AISisOxo) (OH)
The silicon oxide and muscovite are added to the partially polymerized material used to produce the methacrylic resin plate, and then uniformly added to the base material as shown in Figure 1. Plate thickness 5■
A methacrylic resin board was created.

For comparison of t'fc, methacrylic resin plates made of silicon oxide alone and muscovite alone were also prepared. The evaluation results of the sample by these authors are shown in Table 1. Note that FIG. 1 shows a diffusion plate obtained by uniformly adding silicon oxide and muscovite to a base material in the same manner as in this example, and (1) is the diffusion plate.

Table 1 Note that the average particle size is generally used in the case of silicon oxide, but in the case of plate-shaped crystals such as muscovite, it cannot be said to be correct in a strict sense.

However, in the case of muscovite as well, it is common to assume that it has a spherical shape equivalent to seven squares and call it the particle size, so this is followed. Furthermore, the average particle size means that 80% of the particles fall within that range.

Among the evaluation items, see-through was evaluated as × if the outline of the fluorescent lamp was clearly visible when viewed through a fluorescent lamp 10 meters away, and ○ if it was not visible. The screen gain was determined by illuminating the sample with a constant illuminance, measuring the brightness on the opposite side, and calculating the ratio of the two. Furthermore, cutting performance was determined by continuously cutting the diffuser plate and measuring the cutting length until the saw was replaced.

Samples ① to 1 in this example show the mixing ratio of the products of the present invention with no see-through. In contrast, sample ■～0
is an example of a mixing ratio that causes see-through, and the limit that does not cause see-through happens to be the silicon oxide shown in the sample.

They coincide with the line connecting the see-through limit when muscovite is added alone (see Figure 3).

In addition, samples ■~■ had a total light transmittance of 85 cm or more and a well-balanced screen gain of 7''L.On the other hand, samples ■~0 had a high total light transmittance, but had a high screen gain. However, as mentioned above, see-through occurred, which was undesirable.

Muscovite son-t''nn single samples @ and ■ can also be used, but @ requires frequent saw replacement during cutting, and total light transmittance is slightly lower. Regarding cutting performance, sample ① was used as a representative example, but compared to sample ＠, the cutting length was several times that of sample ＠, and the frequency of saw replacement was extremely low.

The above explanation has been given with examples, but to provide a further explanation, when the average particle size of silicon oxide is less than 1p, the diffusivity is too strong and the total light transmittance decreases, and on the other hand, when it exceeds 10μ, the see-through is reduced. 1 to 1 because it will become stronger
It is preferable to set it in the range of 0μ. The amount added at this time is about 10 to 60 t/rn2. Furthermore, if the average particle size of muscovite is less than 15p, there is no effect on see-through, and if it exceeds 40μ, large particles will inevitably be included, which has the disadvantage of degrading the appearance when used as a diffuser plate. . Moreover, when manufacturing the diffuser plate, it is possible to filter partially polymerized substances, but if the particle size is large, it may cause clogging of the f-filter, which is not desirable. From the above, in the present invention, the average particle size is 15 to
Preferably, muscovite in the 40μ range is used. Also,
The addition t of muscovite at this time is preferably 10017 m'' or less, particularly about 50 to 6 ot/m2.Furthermore, the mixing ratio of silica oxide and muscovite that does not cause see-through is as shown in the above example. By measuring the total light transmittance and the limit of see-through in a single system, it is possible to determine the approximate ratio to the set value.

Above, an example in which it is added uniformly to methacrylic resin has been described, but Kinoe 8A is not limited to this example.
It is also possible to make a diffusion plate by dispersing silicon oxide and muscovite having average particle diameters in the same range in a paint and coating it on a transparent substrate. An example of this is shown in Figure 2, where QJ) is a transparent substrate, (6) is a coating layer containing silicon oxide and muscovite, and (1) is a transparent substrate.
) is the obtained diffuser plate.

In the present invention, it is also effective to form various lenticular lenses; it is also possible to provide a Fresnel lens to brighten the entire diffuser plate. Furthermore, it is also effective to provide fine irregularities on the surface during hot pressing or polymerization, and it is also possible to compensate for the diffusible gold by this process.

Of course, it is also possible to combine two or more of these lenticular lenses, Fresnel lenses, and fine irregularities as necessary.

Note that transparent materials such as glass or synthetic resin are generally used as the base material of the diffuser plate of the present invention, but among these,
The methacrylic resin mentioned above.

Synthetic resin materials such as polycarbonate resin, vinyl chloride resin, and styrene resin are particularly suitable.

(Effects of the Invention) Since the present invention has the structure as described in detail above, it has the advantage that a diffuser plate having high light transmittance, extremely little see-through, and good workability can be easily obtained.

[Brief explanation of the drawing]

1 and 2 are enlarged sectional views showing examples of the diffuser plate of the present invention, and FIG. 3 is a graph showing evaluation of the examples. (1)・・・Diffusion plate α■・・・Transparent substrate (2)・・・Coating layer

Claims (1)

[Claims] 1. Silicon oxide with an average particle size of 1 to 10μ, and an average particle size of 1
A diffusion plate characterized in that 5 to 40 p of muscovite is added in an opening that does not cause see-through. 2 Silicon oxide and muscovite are uniformly added to the base material
The diffuser plate according to claim 1, characterized in that: & The diffusion plate according to claim 1, wherein a coating layer containing silicon oxide and muscovite is formed. 4. Claims 1, 2, or 3, characterized in that a lenticular lens, a Fresnel lens, or at least 1''' of fine irregularities are provided.
Diffusion plate as described in section.