JPH1144914A - Reflection type screen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reflection luminance of a screen and to project a distinct video by incorporating titanium oxide-coated mica in a projection type reflection screen and using a synthetic mica as such mica. SOLUTION: This reflection type screen 12 is equipped with a plate-like base material 26, a light reflection surface 28 formed on the material 26, a thin film 30 incorporating a pearl agent using the synthetic mica and a light diffusion layer 32. The synthetic mica in which coloring metal is extremely hardly mixed and whose saturation is excellent is used in the pearl agent to be used. The titanium oxide-coated mica faces in an optional direction in the thin film 30 incorporating the pearl agent, so that the video is viewed at a wide angle with respect to the front of the screen 12. Namely, since the synthetic mica in which the metal is not mixed and whose saturation is excellent is used, there is no possibility that light is absorbed, weakened or colored when it is transmitted through. Then, the loss of the light is restrained to the minimum because of diffusion by refraction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reflective screen,
In particular, it relates to improvement of mica powder contained in a pearl agent.

[0002]

2. Description of the Related Art In general, projector-type televisions and the like have an advantage that they can easily display a large screen and are less affected by radiation and the like. Such a display device projects an image on a screen. The screen projects an image from an observation side of the screen, and a reflective screen for observing a reflected image, and projects an image from the back side of the screen. There is a transmission screen for observing a transmission image. Among them, the reflection type screen is provided with a light reflection surface and a light diffusion layer on a base material. In recent years, the technical development of the screen has been to increase the reflection luminance with respect to the amount of light projected and to produce a bright image at a wide angle. Improvements for visual recognition have become mainstream. Under such circumstances, in the light-reflecting and light-diffusing layers, a pearlescent agent using powder coated with titanium dioxide on the mica surface, a screen with glass beads spread on the screen surface, or providing irregularities on the screen surface Although there are some, the performance of the screen has been remarkably advanced, but there is still room for improvement in the reflection luminance and the clear viewing angle.

In particular, it is disclosed in Japanese Patent Application Laid-Open No. 3-20947 to use a pearlescent agent using a powder of mica coated with titanium dioxide in order to improve the reflection brightness of the screen and to aim for multiple reflection of light. As disclosed in Japanese Unexamined Patent Publication Nos. Hei 3-249634, JP-A-4-139437, and JP-A-4-179943, it is a known technique that is already widely used.

[0004]

However, in actuality, the color of the projected image becomes dark, it cannot be said that it is a vivid image, and its reflection luminance is not so high. It is hard to say that the reproducibility and the reflection luminance are always the expected effects. These were due to the properties of the titanium dioxide-coated mica, and were thought to be the limits of the performance of the titanium dioxide-coated mica.

Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to improve mica used for a pearling agent and mica coated with titanium oxide.
It is an object of the present invention to provide a reflection type screen capable of increasing the reflection luminance of the screen and projecting a vivid image.

[0006]

According to the inventor's intensive studies to achieve the above object, the above-mentioned negative effect is not necessarily caused by titanium dioxide-coated mica but by the properties of mica itself. all right. Natural mica has a slight coloring due to the presence of a small amount of metal, so that the projected light does not affect the light reflected on the mica surface or titanium dioxide surface, but the projected light is large. The part passes through the titanium dioxide and mica to reach the light reflecting surface, and again passes through the titanium dioxide and the mica and is projected on the screen, so that it is significantly affected by the slight coloring of the mica, and therefore the mica The color of the projection light is changed due to the effect of the trace metal contained therein, or the light is absorbed and the reflection luminance is reduced.

That is, in the reflection type screen and the projection type display device according to the present invention, the mica used for the pearling agent solves the problem of coloring by the trace metal described above.
The present invention is characterized by using synthetic mica with very low saturation of coloring metal and good saturation.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of a reflective screen and a projection display device according to one embodiment of the present invention, and FIG. 2 is a conceptual diagram of a configuration of a reflective screen according to one embodiment of the present invention. .

The light projected from the projection display device 10 of FIG. 1 is projected at a certain angle so as to be largely projected on the reflection type screen 12. In FIG. 1, the light projected on the upper end of the screen is called projection light 14, and the light projected on the lower end of the screen is called projection light 16. The projection light 14 reaches the screen and is reflected. If the screen performs only specular reflection, the reflected light is reflected at a reflection angle equal to the incident angle like the original reflected light 18, and
It does not reach the observer 20, that is, the observer cannot see. In this case, it is necessary to reflect the projection light in the direction of the observer so that the projection light projected from the projection display device can be viewed as an image by the observer. In addition, when the number of observers is large, the projection light must be reflected in a wide direction so that many people can view the image. For this reason, the projection light 14 reaches the screen and is reflected and diffused at a wide angle as shown by a dotted arrow, and a part of the diffuse reflected light is visually recognized by the observer 20 as reflected light 22. The same applies to the lower end. The projection light 16 is
The light reaches the screen and is reflected and diffused at a wide angle as indicated by a dotted arrow, and a part of the diffuse reflected light is visually recognized by the observer 20 as reflected light 24. The projection light projected from the projection display apparatus in this manner can project an image to the observer by the same reflection and diffusion at all portions on the screen where the projection light is projected.

The reflection type screen 12 shown in FIG.
And a light-reflecting surface 28 formed thereon and a thin film 3 containing a pearlescent agent using synthetic mica.
0 and a light diffusion layer 32, and the projected light reflects and diffuses a part of the light diffusion layer 32 and the thin film 30 containing the pearl agent from the screen surface on the titanium oxide surface of the pearl agent or the synthetic mica surface. Part of the thin film containing the pearlescent agent is transmitted through the thin film containing the pearlescent agent on the light reflecting surface or totally reflected, and is transmitted while being reflected and diffused on the titanium oxide surface of the pearlescent agent or the synthetic mica surface. Light diffused in multiple directions by the coated synthetic mica is further diffused in multiple directions by a light diffusion layer subjected to embossing or the like. In this way, the screen can project a bright image at a wide angle on the projected light.

By the way, the production of a screen having a high reflection luminance and a wide bright field angle requires two contradictory steps. In other words, in order to provide a reflective screen and a projection display device with high reflection luminance, it is better to suppress the diffusion of the projected light and narrow the light to a certain range. However, the image projected on the screen needs to be able to project a bright image at a wide angle so that many people can see it, and in order to have a wide viewing angle the projected light can be As far as it has to spread.

It can be said that a screen capable of having two contradictory properties at the same time is an excellent screen.
Therefore, in order to have these two conflicting properties,
The problem is how the projected light can be efficiently reflected and diffused, and how the loss of light can be reduced in the process.

A feature of the present invention is to project a vivid image with a high reflection luminance of the screen, that is, to enable viewing of a bright and bright projected image. In the embodiment, in the pearl agent to be used, synthetic mica with good saturation and extremely little colorant metal is used. That is, light reflection,
It is a pearl agent using synthetic mica powder that can suppress loss of light in the process of scattering.

As shown in FIG. 3, a thin film 30 containing a pearl agent
Inside, the titanium oxide-coated synthetic mica 34 is oriented in an arbitrary direction, whereby the projection light 36 is reflected on the surface of the titanium oxide or the synthetic mica powder, or the titanium oxide,
By refracting light in the process of transmitting through the synthetic mica powder, an image can be viewed at a wide angle with respect to the front of the screen. And in this case, the diffusion of light is mainly titanium oxide,
This is due to refraction in the process of transmitting through the synthetic mica powder.

In the case where a titanium oxide-coated mica using natural mica is used, the projected light passes through the titanium oxide-coated natural mica because the natural mica is colored due to the inclusion of a trace amount of metal. When doing so, the result is a bad influence such as that the light is weakened or the color of the projected light is changed by the influence of coloring. Also, the projected light does not always pass through natural mica only once, but the possibility of being transmitted through natural mica again after being reflected on the light reflecting surface and the titanium oxide-coated natural mica once transmitted Considering that it passes through another titanium oxide-coated natural mica,
It transmits twice or three times through natural mica, and the adverse effect on the light of natural mica has a great significance in spite of slight coloring.

Also, let us consider a case in which reflection and diffusion, for example, aluminum powder are used for reflection and diffusion instead of diffusion due to refraction as in the case of this pearl agent. As shown in FIG. 4, the aluminum powder 42 also exists at an arbitrary position in the thin film. Since the aluminum powder does not transmit light, the projection light 44 is reflected on the surface of the aluminum powder and is reflected on the surface of another aluminum powder. Is repeated until light escapes from the screen surface again. However, when the irregular reflection is repeated in this manner, the optical path length becomes much longer than the diffusion caused by refraction such as a pearl agent, which causes the intensity of the reflected light to decrease, and eventually, the reflection efficiency deteriorates. I will.

However, according to the present invention, since synthetic mica having good saturation and containing no metal is used, light may be absorbed, weakened, or colored when light is transmitted. Not at all. Further, since the light loss is caused by diffusion, it is possible to minimize light loss. As described above, the characteristic of the present invention is that the use of synthetic mica having good saturation without the incorporation of metal minimizes the loss of light, thereby increasing the reflection brightness of the screen and widening the angle of reflection. Thus, it is possible to realize a reflection type screen and a projection type display device capable of projecting a vivid image.

Here, an example of the synthetic mica used in the present invention is represented by the following general formula. X _1/3 to ₁ Y ₂ to ₃ (Z ₄ O ₁₀ ) F ₂ (where X is Na ⁺ , K ⁺ , Li ⁺ , Ca ²⁺ , Rb ²⁺ , Sr
²⁺ represents one or more ions selected from the group consisting of
Are Mg ²⁺ , Fe ²⁺ , Ni ²⁺ , Mn ²⁺ , Al ³⁺ , Fe ³⁺ ,
Represents one or more ions selected from the group consisting of li ^+, Z is ^{Al 3+, Si 4 +, Ge} 4+, Fe 3+, represents one or more ions selected from the group consisting of B ^3+. A general method for producing synthetic mica powder is, for example, in the case of synthetic fluorophlogopite, after mixing about 40 parts of silicic anhydride, about 30 parts of magnesium oxide, about 13 parts of aluminum oxide and about 17 parts of potassium silicofluoride, It is melted at 1400-1500 ° C. and crystallized at 1300-1400 ° C. to obtain synthetic fluorophlogopite (KMg (AlSi ₃ O ₁₀ ) F ₂ ). The obtained ore of synthetic fluorophlogopite is crushed and classified to obtain a synthetic fluorophlogopite powder. The shape of the synthetic fluorophlogopite powder thus obtained is in the form of an irregular plate, and its particle size depends on the application, but is generally 0.05 to 10 in the thickness direction.
μm, and the plane direction is 2 to 200 μm.

A reflection type screen and a projection type display device according to an embodiment of the present invention are provided with a light reflecting surface on a base material, and further laminated in the order of a pearl agent using synthetic mica according to the present invention, and a light diffusion layer. It is composed.

As the base material, materials such as white plastic sheet, polyolefin such as polyvinyl chloride, polyethylene and polypropylene, polyester such as polyethylene terephthalate, polystyrene, polycarbonate, acrylic resin and polyurethane resin can be used. If necessary, a plasticizer may be added to the resin in an amount of 20 to 100% by weight. The thickness of the substrate is preferably from 10 to 1000 μm.

As the light reflecting surface, an aluminum foil, an aluminum plate, an aluminum vapor-deposited film, an aluminum powder or the like can be used. Further, a thin film is formed thereon with a pearl agent using the synthetic mica according to the present invention.

As the light diffusion layer, a plastic film, polypropylene, vinyl chloride, polyethylene terephthalate, triacetyl cellulose film or the like can be used, and it is preferable to use a film whose surface is embossed or matted. Light reflection surface, thin film by pearl agent, light diffusion layer, screen printing method, roll coating method,
Examples thereof include a method of printing by offset printing and the like, and a method of coating with a knife coater, a comma coater and the like.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. After mixing 40 parts of silicic anhydride, 30 parts of magnesium oxide, 13 parts of aluminum oxide and 17 parts of potassium silicofluoride, synthetic fluorophlogopite fused at 1500 ° C. and crystallized at 1350 ° C. was coarsely pulverized and finely pulverized. Diameter 20 ~ 100μm
(Sedigraph 5000-0 manufactured by Micromeritics Co., Ltd.
100 parts of a synthetic fluorogold synthetic mica powder having a spherical equivalent value (measurement method of particle size is hereinafter the same) measured by a mold 1) was obtained. Further, 50 parts of the obtained synthetic mica was added to 500 parts of ion-exchanged water, sufficiently stirred, and uniformly dispersed. An aqueous solution of titanyl sulfate having a concentration of 40% by weight was added to the obtained dispersion.
8.5 parts were added, and it heated and boiled for 6 hours, stirring. After allowing to cool, it was filtered, washed with water, and calcined at 900 ° C. to obtain 90 parts of synthetic mica coated with titanium dioxide. A pearl agent using this synthetic mica powder was added to an acrylic resin lacquer and dispersed and mixed with a homogenizer to obtain a pearl agent ink. A 200 μm thick polyvinyl chloride sheet was used as a base material, and a 600 mm long, 600 mm wide metal aluminum foil was stuck thereon, and a pearlescent ink using synthetic mica according to the present invention was formed thereon to a thickness of 100 μm. After the silk printing, a polysiloxane resin was further silk-printed thereon so as to have a thickness of 100 μm to obtain a projection reflective screen. The application amount of the pearl agent per unit area is about 20 mg / cm ² .

[Production of Comparative Example 1] A screen prepared according to the same procedure as in the example of the present invention, but using a pearl agent using natural mica instead of the pearl agent according to the present invention (hereinafter referred to as Comparative Example 1) Was manufactured, and the performance of the reflective screen according to the present invention was compared with a comparative experiment.

[Production of Comparative Example 2] A screen prepared by the same procedure as in the example of the present invention was prepared by using a screen using aluminum powder instead of the pearling agent according to the present invention (hereinafter referred to as Comparative Example 2). A comparison experiment was conducted with the performance of the reflective screen according to the present invention.

[Experimental Results] A comparison experiment of the performance of the screen was performed by comparing a screen gauge value (hereinafter referred to as an SG value) indicating a value of π times the ratio of the reflection luminance at the front of the screen to the incident illuminance of the screen, and a reflection at the front of the screen. The angle value at which the luminance becomes half the value (hereinafter referred to as the half value angle)
And three values of reproducibility (hereinafter referred to as reproducibility) with respect to the color of the projected image were determined.

When a comparative experiment was performed as described above,
The results shown in Table 1 below were obtained. In the evaluation of the screen performance, the SG value and the half-value angle are represented by numerical values by actual measurement, and the larger the numerical value, the better the performance, and the reproducibility is as follows. The color of the image projected on the screen was compared with the color of the actual film, and evaluated on a five-point scale of very good ◎, good 、, normal △, bad x, and very bad XX.

[Table 1] ──────────────────────────────────── Comparison item SG value Half value angle Reproducibility ── ────────────────────────────────── Product of the present invention 5.0 ± 35 ° ◎ ────── ────────────────────────────── Comparative Example 1 4.0 ± 30 ° ○ ────────── ────────────────────────── Comparative Example 2 4.0 ± 10 ° ○ ────────────── ──────────────────────

As shown in Table 1, in Comparative Example 1, the SG value,
Although the half value angle shows a good result to some extent, it is not preferable in terms of reproducibility. In Comparative Example 2, the SG value and the reproducibility were good to some extent, but sufficient results could not be obtained for the half-value angle. However, the performance of the reflection type screen using the pearl agent using the synthetic mica powder according to the present invention showed good results in all the items tested.

Next, an experiment was conducted on the effect on the performance of the screen using a pearl agent using a synthetic mica powder having a different particle diameter and coated with titanium dioxide having a constant layer thickness. In this experiment, the layer thickness of titanium dioxide was uniformly set at 40 nm. As a result, the results shown in the following Table 2 were obtained. The way of expressing the evaluation is the same as in Table 1.

[Table 2] {Particle size 25 20 60 80 100 200} ─────────────────────────────────── SG value 3.0 4.4 4.5 4.5 4.6 4 .8 5.0 4.8 ──────────────────────────────────── Half-value angle ± 15 ° ± 30 ° ± 30 ° ± 30 ° ± 35 ° ± 35 ° ± 35 ° ───────────────────────────────── ─── 粒径 Particle size 25 20 60 80 100 200 200 ────────────────────────────────── Reproducibility ○ ○ ○ ◎ ◎ ◎ ◎ ────── ───────────────────────────── The unit particle size in Table 2 is [mu] m.

From the results shown in Table 2, it is understood that the particle size of the synthetic mica powder used in the present invention is preferably about 5 μm to 200 μm. As a result, there is data indicating that the particle size of natural mica shows good results when the particle size is 5 to 60 μm. However, the synthetic mica according to the present invention, which contains a very small amount of a coloring metal, shows good results even at a larger particle size. I have.

Further, there is the following data on the interference color of the titanium dioxide-coated synthetic mica according to the thickness of the titanium dioxide layer coated on the surface of the synthetic mica powder. (Interference color) (Geometric thickness of titanium dioxide [nm]) ─────────────────────────────────銀 silver 20-40 thin gold 40-90 gold 40-90 red 90-110 violet 110-120 blue 120-135 green 135-155 second-order gold 155-175 second-order violet 175-200

Then, an experiment was conducted on the performance of the screen using the titanium dioxide-coated synthetic mica powder for each different layer thickness of titanium dioxide, and the results shown in the following Tables 3 and 4 were obtained. In this experiment, the particle size of the synthetic mica was uniformly set to 60 μm. The way of expressing the evaluation is the same as Tables 1 and 2.

[Table 3] {Layer thickness 5 10 20 30 40} Ｇ SG value 3.0 4.0 4.8 5.0 5.0 ──────────────────────────────────── Half angle ± 15 ° ± 20 ° ± 35 ° ± 35 ° ± 35 ° ──────────────────────────────────── Reproducibility ○ ○ ◎ ◎ ◎ ──── ────────────────────────────────

[Table 4] {Layer thickness 50 80 100 150 200} ───────────────────────────────── SG value 5.0 4.9 4.8 4.5 4.5 4.5 ──────────────────────────────────── Half angle ± 30 ° ± 25 ° ± 20 ° ± 20 ° ± 20 ° ──────────────────────────────────── Reproducibility ○ △ △ △ × ────単 位 The unit of the layer thickness in Tables 3 and 4 is nm. From the results of Tables 3 and 4, the thickness of the titanium dioxide layer coated on the surface of the synthetic mica in the present invention is from 20 nm to 40 nm.
Preferably it is of the order of magnitude.

As described above, the performance of the screen is further improved by using the synthetic mica of the present invention, which has a very small amount of the coloring metal and has a good chroma. In particular, the particle diameter is 5 μm to 200 μm, and the layer thickness is 20 nm to 40 n.
m is most effective.

[0034]

As described above, according to the reflection type screen and the projection type display device of the present invention, the mica used for the pearling agent and the mica coated with titanium oxide have a color saturation with extremely small mixing of a coloring metal. By using good synthetic mica, it is possible to provide a reflection type screen and a projection type display device capable of increasing the reflection luminance of the screen and observing a clear image at a wide angle.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a reflective screen and a projection display device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a configuration of a reflective screen according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of the behavior of incident light in a thin film formed by a pearl agent.

FIG. 4 is a diagram illustrating the behavior of incident light when aluminum powder is used instead of a pearl agent.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Projection display apparatus 12 Reflection screen 14 Projection light 16 Projection light 18 Original reflection light 20 Observer 22 Reflection light 24 Reflection light 26 Base material 28 Light reflection surface 30 Thin film containing a pearl agent 32 Light diffusion layer 34 Titanium oxide coating Synthetic mica 36 Projected light 38 Reflected light 40 Reflected light by titanium oxide-coated synthetic mica 42 Aluminum powder 44 Projected light 46 Light reflecting surface 48 Reflected light

Claims (1)

[Claims] 1. A projection type reflection screen including a light reflection surface formed on a base material and a light diffusion layer formed on the light reflection surface, wherein the projection type reflection screen includes mica coated with titanium oxide. Wherein the mica is a synthetic mica.