JPS5872935A - Transmission type screen - Google Patents

Abstract

PURPOSE:To obtain a high-transmittance and high-contrast transmission type screen, by using a neodymium oxide as a light diffusing material and adding glass beads containing the light diffusing material to form a lenticular plate having a light diffusing part. CONSTITUTION:As a light-transmittable medium, a lenticular plate 7a is formed where an acrylic acid ester resin or the like is used and plural semicylindrical lenses 8' are provided and many light diffusing materials 9 are dispersed. Glass beads containing an oxide Nd2O3 of neodymium Nd of a rare earth element are used as light diffusing materials 9. The transparent medium where these beads are dispersed is used to the lenticular plate 7a, thus obtaining a transmission type screen. The spectral transmittance (%) of glass beads containing the Nd2O3 is constant in the visible region indicated by a dotted line (b), and the transmission type screen has high transmittance and high contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmissive screen used in a transmissive video projector system, etc., and particularly to a transmissive screen that can improve the contrast of a projected image without impairing light transmittance. It is an object of the present invention to provide a transmissive screen having an improved light diffusion section.

A video projector system that projects an image obtained on a cathode ray tube or the like onto a screen so that the enlarged image can be viewed includes a video projector system that projects an image onto a reflective screen and There are two types of video projectors: a reflective type, in which the image is viewed from above the screen, and a transmissive type, in which the image is projected onto a screen and the image on the screen is viewed from the opposite side of the screen from the projection side1.Transparent type video projectors・As shown in FIG. 1, the system is usually configured so that the image obtained on the panel of the cathode ray tube 1 is enlarged and formed on the transmission screen 3 by a projection lens, and The enlarged image is viewed by the transmitted light passing through the transmission screen 3.

In this case, in order to make the image on the transparent screen 3 seen by the celebrant as bright as possible, the transmitted light from the transparent screen 3 is given directionality, and most of the light incident on the transparent screen 3 is directed to the celebrant. It is necessary to allow the light to pass in the direction of the screen.

Therefore, it is required that the transmitted light from each pixel 5 formed on the transmission screen 3 has a predetermined transmitted light divergence angle ψ. This transmitted light divergence angle ψ is, for example,
Appropriate values are approximately 20 degrees in the vertical direction and approximately 90 degrees in the horizontal direction; if these values are not selected, the jealous viewer may find that the fixation person is within the divergence angle of the transmitted light. A phenomenon called a so-called hot spot occurs, in which only certain pixels within the display appear to be particularly bright.This is a fatal flaw for a display device, and makes the entire projector system unusable. There is a risk that it will become.

A transmissive screen in which the transmitted light from each pixel has an appropriate divergence angle as described above is generally constructed as shown in FIG. 2 or 3. The screen shown in Fig. 2 is a two-piece screen in which a Fresnel lens plate 6 and a lenticular plate 7 are arranged so that their back surfaces are aligned (or they are formed integrally). 1, the projected light enters from the side of the Fresnel lens plate 6 which acts as a convex lens, passes through the Fresnel lens plate 6 and the lenticular plate 7, and diverges from the lenticular surface of the lenticular plate 7.
A plurality of semi-cylindrical lenses extending in the vertical direction are arranged on the lenticular surface of the lenticular plate 7, so that a transmitted light divergence angle of about 90 degrees in the horizontal direction is obtained.

Furthermore, the lenticular plate 7 is formed of a light-transmitting material mixed with a light-diffusing agent, or a layer containing a light-diffusing agent is formed on the V-shaped surface of the lenticular plate 7, and The angle of divergence of the transmitted light is approximately 1. Furthermore, the one shown in FIG. 3 is also composed of a Fresnel lens plate 6 and a lenticular plate 7, but unlike the one shown in FIG. It is arranged so that The projected light enters from the Fresnel lens plate 6 side, passes through the Fresnel lens plate 6, enters the lenticular plate 7 from its lenticular surface, and diverges from its back surface.

In this case as well, a plurality of vertically extending semicylindrical lenses S arranged on the lenticular plate 70V/ticular surface provide a transmitted light divergence angle of about 90 degrees in the horizontal direction, and the lenticular plate 7 is formed of a light-transmitting material mixed with a light-diffusing agent, or a layer containing a light-diffusing agent is formed on the back side of the lenticular plate 7, so that the transmitted light divergence angle of about 2θ degrees in the vertical direction is formed. It is made possible to obtain.

However, in the past, silicon oxide (S 1ox), aluminum oxide (A1203), and titanium oxide have been used as light diffusing agents to obtain a predetermined vertical transmission light divergence angle in such a transmission screen. (Tio 2),
Zinc oxide (ZnO), barium sulfate (BaSO),
One or a mixture of two or more of calcium carbonate (CaCO3), organic diffusing agents, etc. is used.
Since the body color of all of these light diffusing agents is white, conventional transmissive screens using these light diffusing agents do not allow the outside light to be reflected by the light diffusing agent under a certain level of external light. The drawback was that sufficient contrast performance could not be obtained3.For this reason, some products mixed black dye with a light diffusing agent to reduce the reflection of external light and improve contrast performance. This has the disadvantage that it is accompanied by a decrease in the light transmittance (screen gain) of the screen.

In order to eliminate the shortcomings or inconveniences associated with the conventional transmissive screen as described above, the present invention provides a screen that provides sufficient contrast performance even under strong external light, provides faithful color reproduction, and is bright. The transmissive screen according to the present invention, which provides a transmissive screen with an improved light diffusion section that can obtain an image, will be described below with reference to embodiments of the present invention. For example, as shown in FIG. 2 or 3 above, it is composed of a combination of a Fresnel lens plate and a lenticular plate, and its characteristics are as follows.
The light diffusing portion formed in association with the lenticular plate is formed using a special glass bead total light diffusing material having selected spectral transmission characteristics. 1 is a cross-sectional view showing an example of a light diffusing part of such a transmission type screen. In this Reli, the lenticular plate 7 constituting the transmission type screen as shown in FIG. 2 or 3 is a novel light diffusion material 9. A light-transmitting medium doped with [ZIJ, for example, made of an acrylic ester resin is used as a lenticular plate 7a, and a plurality of semicylindrical lenses g' extending in the vertical direction arranged on the lenticular surface of the lenticular plate 7a produce a transverse angle of 9θ. This is a case where a light diffusing portion is formed which can obtain a transmitted light divergence angle of approximately 20 degrees and also generate a transmitted light divergence angle of approximately 20 degrees in the vertical direction. The light diffusing material is made of neodymium (Na), a rare earth element.
Glass beads containing neodymium oxide (Na 0.?), which is an oxide of ), are used. The diameter of these glass beads is 3 to 30 μm, on average /! f11m, and its composition is 5i02, Al2O,7, strontium oxide (SrO), barium oxide (B
aO), ZnO, sodium oxide (Na20), potassium oxide (K2O), TiO, etc., which contains Nd2O3 at lθ to 35% by weight.

Such Nd2O3-containing glass beads have spectral transmission and transmission characteristics as shown by the solid line a in FIG. Shows a sharp drop in spectral transmittance to light.

part, about Slθ~s3'on m and about sqo~rq
.

It has a characteristic that there is a light absorption wavelength band in which light is absorbed in the nm wavelength band. In addition, the broken line in Figure S is N.
1 shows the spectral transmittance of glass beads not contained in d2O3, and 3 shows the spectral transmittance of glass beads not contained in d2O3.
~IQ weight percent is added and uniformly dispersed, and the lenticular plate 7a is molded using this medium by extrusion molding, injection molding, hot press molding, etc. 4 Here, the above-mentioned glass beads are f”Jci2o
The value of lO~3Yujusai bar liquid for the content of J and Nd207' for the light-transmitting medium! ? The numerical value of 3 to 10 weight percent of the added glass heath is to obtain an appropriate transmitted light divergence angle required for the above-mentioned transmission type screen, that is, a transmitted light divergence angle of about 20 degrees in the vertical direction. If the cathode ray tube t used in the transmissive video 10-diode system with M'/Ro shown in the figure is a color cathode ray tube, it is formed in the panel part. For color fluorescent surfaces, rare earth Y2O3: Ell is generally used as a red light phosphor and green is used.

Among these phosphors, the emission spectrum of the red-light phosphor is as shown in FIG. It has around lQnm,
The sub-peaks of light emission are near the wavelength of about tAO-4oOnm and about 630 n In. The emission spectrum of the phosphor for green light is as shown in Figure 7.
00 m, and the emission sub-peak is wavelength-wise.
~7190 nm, approx. ;gO~! ; It has around 90 nm and around the island J nm. Furthermore, the emission spectrum of the phosphor for blue light is as shown in FIG. 3, and the emission peak is near the wavelength vson m.

Therefore, the light from the color cathode ray tube is projected onto the transmission screen according to the invention having the above-described lenticular plate 7a shown in FIG. V, which passes through the Fresnel lens plate and enters the lenticular plate 7a. The red light, green light, and blue light at the main peaks of the respective emission spectra from the red light phosphor, green light phosphor, and blue light phosphor are diffused by the lenticular plate 7a. Material 9
Nd203f mixed as Nd203f: Since it is not in the light absorption wavelength band of the glass beam contained, that is, about 5io-530nm and about 570-S90nm wavelength band, Nd2
without being absorbed together with glass containing O3,
1, which is diffused by the glass beam containing Nd203f and emanates from the lenticular plate 7a.
Wavelength tgo of the emission spectrum of red and green phosphors at subpeaks around ~600 nm ~5
? The green light at the sub-peak near On m is due to Nd2
approximately 5, which is the optical absorption wavelength band of the glass beam containing O3.
It is in the wavelength band region of qo-ta qOnm, and Nd
As a result, the light emitted from the lenticular plate 7a is absorbed by the glass beam containing 20yk.1 As a result, the light emitted from the lenticular plate 7a is at the main peak of the emission spectrum of each phosphor forming the phosphor surface of the color cathode ray tube. Since each color light at the sub-peak is reduced for each color light,
Lenticular board? The color image on the transmissive screen having the color a has increased color purity and faithful color reproduction. Furthermore, since blue light phosphors do not have subpeaks in their emission spectrum, there is no such thing as blue light in the subpeaks of their emission spectrum from blue light phosphors, but blue light in the main peak. only is emanated from the lenticular plate a.

In addition, among the external light incident on the transmission screen having the lenticular plate a mixed with glass beads containing Nd2O3', the light in the light absorption wavelength band of the glass beads containing Nd2O3e is contained in Nd2O3'e. Since it is absorbed by the glass beads and not reflected, the reflection of external light from the screen to the viewer is reduced.In addition, the glass beads have a lower reflection rate than the various light diffusing agents previously used. Because the ratio is low, the contrast of the image on the screen is significantly improved compared to the prior art.

Furthermore, N (32
Since only the red light and green light in the sub-peaks of the emission spectrum of the red light phosphor and the green light phosphor are absorbed by the glass beads containing Nd.
203'c Gold-containing glass beads do not substantially reduce the light transmittance (screen gain) of the screen, and a bright image can be obtained on the screen 11. Next, FIGS. 9 to 72 FIG. 3 is a cross-sectional view showing another example of the light diffusing portion of the transmission screen according to the present invention.

In the example shown in FIG. 9, a layered portion IQ containing glass beads containing Na2O3 as a light diffusing material 9 is formed on one surface of the 7-inch lenticular plate 7 arranged as shown in FIG. A lenticular plate 7b is used as a light diffusing section. In this case, 3 to 10 weight percent of glass beads having a diameter of 3 to 30 μm and containing 10 to 35 weight bars of Nd2O3 are added to a light-transmitting medium such as an acrylic acid ester resin,
A lenticular plate is molded by this lIY body, and at that time, the glass beads are deposited and arranged on the lenticular surface portion 11+11 by utilizing the difference in specific gravity between the medium and the glass beads, and a layered plate containing glass beads containing N (3203) is formed. 3 forming part 10, and the reli shown in FIG. 70 includes glass beads containing Nd2O3 as a light diffusing material on the back side of the lenticular plate 7 arranged as shown in FIG. A layered portion // is formed to form a lenticular plate 7C, which serves as a light diffusing portion.

In this case as well, in the same way as the example in FIG. 3, glass beads containing Nd2O3 are added to a light-transmissive medium such as acrylic acid ester resin, and a lenticular plate is molded using this medium. By utilizing the difference in specific gravity between the glass beads and the glass beads, the glass beads are settled and placed on the back side of the lenticular plate.

Lenticular plate 7 arranged as shown in FIG.
Nd20 as a light diffusing material is placed on the V-chillar surface of the
The light spreading layer 12 is formed by applying a paint containing glass beads containing 3ffi.1 This paint has a diameter of 3 to 30 μm on a light-transmitting medium such as an acrylic resin, and Glass beads containing lθ to 35 weight percent of N (1203) are uniformly dispersed with addition of 3 to lθ heavy acid.Furthermore, [+lJ in FIG. On the back side of the lenticular plate 7 to be
The light diffusion layer 13 is formed by applying a paint containing glass beads containing glass beads, and the paint in this case is also the first one.
This is similar to the paint in the Q column. .

In any of the rows shown in FIGS. 9 to 72, glass beads containing Nd2oji as a light diffusing material are used, similar to those described in the explanation of ρ1j shown in FIG. q. It is clear that a depleting effect can be obtained.

As explained above, the transmission screen according to the present invention has the following features:
It has an improved light diffusion part using glass beads containing 10 to 35 weight percent of Nd2O3 as a light diffusion material, and can obtain an appropriate transmitted light divergence angle required for a transmission type screen. At the same time, the image obtained on the screen can have excellent contrast without reducing brightness, and can also have faithful color reproduction.

In the above-mentioned embodiment, only glass beads containing Nd2C)3''!i are used as a material for light diffusion, but in addition to such glass beads, the previously used glass beads mentioned above are used. However, in order to further improve the contrast performance, a small amount of black dye is added to the light diffusing part, even if it sacrifices some light transmittance. Good 4.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a transmissive video projector Φ system, FIGS. 2 and 3 are partial perspective views showing the configuration of a transmissive screen, and FIG. V is light diffusion of a transmissive screen according to the present invention. A sectional view showing an example of the section, from Figure S to Figure S
The figure is a diagram used to explain the function of the light diffusion section in the transmission screen according to the present invention, and FIGS. 9 to 12 each show other examples of the light diffusion section of the transmission screen according to the invention. 1 is a cross-sectional view. In the figure, l is a cathode ray tube, 2 is a projection V7, 3 is a transmission screen, and O is a Funnel lens plate. '7, 7a. 7b and 7C are lenticular plates, g and g' are semicylindrical V-noses, 9 is a light diffusing material, 10 and/or are layered parts, t
2 and 13 are light diffusion layers. . 400 500 600 700 Liquid 5 (nm) Figure 9 Figure 10 Figure 11 Figure 12 v! J

Claims (1)

[Claims] A transmission type screen having a light-diffusing section formed by adding glass beads containing neodymium oxide to a light-transmitting medium.