JPH032854A - Fluorescent screen - Google Patents

Abstract

PURPOSE:To improve the brightness of an entire fluorescent screen by forming the screen of a plate having plural recessed parts which are spaced to be formed on a main surface and plural island-like fluorescent members with which the recessed part is filled. CONSTITUTION:The screen is constituted of the plate 10 having plural hemispherical recessed parts which are spaced to be formed on the main surface and plural fluorescent members 11 having nearly ellipsoidal shape with which the recessed parts are filled. The plate 10 is formed of transparent plastic material, where plural hemispherical recessed parts are spaced and arranged vertically and horizontally as the pattern of scattered dots all over the main surface. The fluorescent member 11 is formed by arranging high-viscosity transparent resin containing phosphor on the hemispherical recessed part of the plate 10. The fluorescent member 11 holds the phosphor which sufficiently protrudes hemispherically from the plate 10 in virtue of the high viscosity of its own after it is hardened. Since the plate 10 is transparent to exciting light, the fluorescence is uniformly emitted ahead when the surface of the plate 10 is irradiated with the exciting light from the plate 10 side and the visual field dependency of the fluorescence is eliminated. Thus, the brightness of a display surface is improved.

Description

TECHNICAL FIELD The present invention relates to a phosphor screen containing phosphors that emit light in response to excitation light.

Background Art Phosphor screens are made of substances (so-called phosphors) that emit fluorescence or phosphorescence in response to excitation light such as ultraviolet light, visible light, or near-infrared light, such as piperidium tetra(benzoyltrifluoroacetone) europium complex. It is known as a flat plate body made by dispersing and molding a transparent synthetic resin.

In such a phosphor screen, an excitation light beam is projected onto the phosphor screen in the form of a circular spot, causing the phosphor within the spot to emit light, which is used as a pixel to display an image. Therefore, the phosphor screen is used, for example, as a display member of a rear projection type or front projection type image display device. In the rear projection type, an excitation light beam is projected from one side (display back surface) of the phosphor screen and light is emitted to the other side (display surface) for viewing by an observer. In the front projection type, an excitation light beam is projected from one side (display surface) of a phosphor screen, and light is emitted to the same side so that the viewer can see it visually.

However, because of the flat plate shape of the phosphor screen of a rear projection type image display device, for example, as shown in FIG. The particles are scattered equally in the direction of both sides of the body screen 20 and in the direction of propagation inside the flat plate. Therefore, the utilization efficiency of the projected excitation light becomes low, and the amount of light emitted to the display surface 2Oa side, which is the viewing side, decreases, resulting in a dark screen.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the conventional screen, and provides a phosphor screen that increases the amount of light emitted to the display surface side and improves the brightness of the display surface for the same amount of excitation light. The purpose is to provide

The phosphor screen according to the present invention is characterized by comprising a flat plate having a plurality of recesses formed at intervals on its main surface, and a number of stages of fluorescent members filled in the recesses.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a partial sectional view of the phosphor screen of this embodiment. This screen is for a rear projection type image display device, and includes a flat plate 10 having a plurality of hemispherical recesses formed at intervals on its main surface, and a plurality of approximately ellipsoidal fluorescent members 11 filled in the recesses. It consists of.

This flat plate 10 is made of a transparent plastic material such as PMMA, and has a plurality of hemispherical recesses 12 as shown in FIG.
The dots a are arranged vertically and horizontally in a scattered pattern at intervals over the entire main surface.

The fluorescent member 11 is made by disposing a high-viscosity transparent resin containing the above-mentioned fluorescent substance on the hemispherical recess 12a of the flat plate 10. Because of its high viscosity, the fluorescent member 11 bulges out from the flat plate 10 in a hemispherical shape after being cured and retains sufficient fluorescent material.

Since such a flat plate 10 is transparent to excitation light, the flat plate 1
When excitation light is irradiated onto the surface from the zero side, fluorescence is uniformly emitted from the front surface, making it possible to eliminate field-of-view dependence of fluorescence.

Furthermore, a plurality of fluorescent members 1 arranged in an island shape on the flat plate 10
1 can be arranged vertically and horizontally as a scattered dot pattern as shown in Figure 2, but as shown in Figure 3,
They can also be arranged in a striped hairline pattern.

In this case as well, the flat plate 10 is made of PMMA or the like, and the third
As shown in the figure, a plurality of parallel grooves 12 are provided at intervals over the entire main surface.

The longitudinal fluorescent member 11 arranged in this parallel groove is, for example,
It is formed from a fluorescent resin containing a transparent synthetic resin as a binder, in which the above-mentioned known fluorescent substance is mixed and dispersed. By irradiating the excitation light beam from the flat plate 10 side, the excitation light transmitted through the flat plate can activate the longitudinal fluorescent member and cause it to emit light.

The manufacture of such a phosphor screen is carried out as follows. For example, PMMA is molded into a flat plate with a predetermined shape by molding the flat plate with grooves or recesses using an injection molding method, and then the phosphor or phosphor-containing synthetic resin is filled from the groove side into the recesses of the deck by coating or the like. Then, heat treatment is performed to form the fluorescent member 11 in the groove or recess, thereby obtaining a fluorescent screen in which the fluorescent member 11 and the flat plate 10 are integrated.

Also, during molding, it is desirable to make the refractive index of the phosphor-containing resin higher than that of the flat plate, and by doing so,
This is preferable because the light emitted by fluorescence is guided further into the flat plate.

Furthermore, in other phosphor screen manufacturing, the phosphor member 11 made of a phosphor-containing resin may be formed in advance as a separate member and fixed to the groove or recess of the flat plate 10 via an adhesive layer. In this case, these materials are selected so that the refractive index of the phosphor tooth decreases in the order of resin, adhesive layer, and flat plate. This is to increase the amount of fluorescence inside the flat plate.

Further, in order to make a phosphor screen for a front projection type image display device, it is possible to use the same configuration as above by dispersing black pigment in the flat plate 10 and making the flat plate 10 a black opaque body. In this case, by irradiating the excitation light flux from the fluorescent member 11 side, which is the viewing side, to the opaque flat plate 10 side,
The excitation light can activate the fluorescent member and cause it to emit light toward the viewing side.

The rear projection type phosphor screen composed of the flat plate 10 and fluorescent members 11 of this embodiment is further improved, and as shown in FIG. It is also possible to form a black body, for example a black area 12 coated with black paint, on the intermediate plate. In this way, as shown in FIG. 5, if the black stripe pattern is formed when viewed from the fluorescent member side, leakage of fluorescence due to crosstalk between the fluorescent members can be prevented, and image contrast can be improved.

Effects of the Invention As described above, according to the present invention, escape of light emitted in the direction perpendicular to the length direction of the fluorescent member is suppressed, and the brightness of the entire phosphor screen is improved.

Furthermore, since the fluorescent members are not continuous and integrated,
So-called leakage light from adjacent fluorescent regions can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an embodiment according to the present invention, FIGS. 2, 3, and 4 are partial perspective views showing an embodiment according to the present invention, and FIG. 5 is a partial sectional view of FIG. FIG. 6 is a partial sectional view showing a conventional example. Explanation of symbols of main parts 10...Flat plate 11...Fluorescent member 12...Black area Fig. 1

Claims (9)

[Claims] (1) A phosphor screen comprising a flat plate having a plurality of recesses formed at intervals on its principal surface, and a plurality of island-shaped fluorescent members filled in the recesses. (2) The phosphor screen according to claim 1, wherein the recesses are parallel grooves formed at intervals, and the fluorescent member is a longitudinal fluorescent member. (3) The phosphor screen according to claim 1 or 2, wherein the flat plate is made of a transparent material. (4) The phosphor screen according to claim 3, further comprising a black area between the recesses. (5) The phosphor screen according to claim 4, wherein the refractive index of the fluorescent member is greater than the refractive index of the flat plate. (6) The phosphor screen according to claim 4, wherein the fluorescent member is fixed to the concave portion of the flat plate via an adhesive layer. (7) The phosphor screen according to claim 6, wherein the refractive index of the fluorescent member, the adhesive layer, and the flat plate decrease in this order. (8) The phosphor screen according to claim 1 or 2, wherein the flat plate is made of an opaque material. (9) The phosphor screen according to claim 8, wherein the opaque material is black.