JPH01195435A - Transmission type screen - Google Patents

Abstract

PURPOSE:To improve the dependency of the angle of visual field by constituting transparent fine elements having reflecting walls on the peripheries in a plate shape so that the respective walls are arranged at an angle perpendicular to or nearly perpendicular to the plane of a side where light is projected. CONSTITUTION:The above screen is constituted in the plate shape as the integrated body of the transparent fine elements 3 having the reflecting walls 2 on the peripheries and the reflecting walls 2 of the respective elements are arranged at the angle perpendicular to or nearly perpendicular to the plate surface of the light projection side. Light made incident on a certain fine element advances in the fine element 3 by multiple reflection by the reflecting wall 2 on the periphery of the fine element 3. And most of it is made incident on the adjacent fine elements 3, so that it does not become stray light. By the alteration of the direction of every reflection and with the roughness of the reflecting wall 2, it has the large distribution of angle. Thus, the projected light becomes diffused light having the wide distribution of angle and shows excellent screen characteristic without depending on the angle of the incident light.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides an illumination system that forms an image of a television, slide, or movie on the back side of the screen so that it can be viewed from the front.
It has a J-type star screen.

Conventional technology A one-piece type in which a Fresnel lens and a lenticular lens are configured on both sides of a single plate (for example, Japanese Patent Application Laid-Open No. 57-21033
3) or a two-piece type that combines a Fresnel lens plate and a lenticular lens plate (for example, Japanese Patent Laid-Open No. 58
-186732) is used. In Figure 2,
An example of projecting a television image will be shown. Incident light flux 2
1 is converted into parallel light 22 by a Fresnel lens 24, and enters a lenticular lens plate 25. The incident light is converted into scattered light 23 by the convex cylindrical lens surface 26 on the surface of the lenticular lens 25, and reaches the viewer's eyes.

Problems to be Solved by the Invention With the configuration shown in FIG. 2, it is expected that the color tone of the projected image will not change no matter what angle it is viewed from. However, as shown in FIG. 3, the CRT for projection is a blue projection tube (B-CRT) 1). Green projection tube (G-CRT) 12, red projection tube (R-CRT)
13 are arranged in a row, the angles of incidence on the screen 20 are slightly different. Since the red light 16 is more strongly incident on the eyes of the viewer 10 than the blue light 14, the screen appears red, and the blue light 17 is more strongly incident on the eyes of the viewer 1) than the red light 19. The screen is blue and confusing. Green light 15.18 has an intermediate feel and does not look particularly strange, but because of this phenomenon, transmissive screens have the problem that the color tone differs depending on the viewing direction.

Means for Solving the Problems In order to solve the above problems, the "transmissive screen" of the present invention is configured in a plate shape as an accumulation of transparent micro elements having a reflective wall around the periphery. is configured to be perpendicular to or close to perpendicular to the plate surface on the output side.

Effect of the present invention With the above-described configuration, the light incident on a certain microelement is multiple reflected by the reflective walls around the microelement and travels within the microelement, so that the light almost always enters the adjacent microelement. , it does not become stray light, and because it changes its direction each time it is reflected and has a large angular distribution due to the roughness of the reflecting wall, the emitted light has a wide width without depending on the angle of the incident light. The light becomes diffused with an angular distribution and exhibits excellent screen characteristics.

EXAMPLE Hereinafter, the present invention will be explained with reference to the drawings regarding an example of a transmission type screen.

FIG. 1 is a diagram showing the basic configuration of the present invention. Minute element 3
has a structure in which a reflective wall is provided around a transparent material 1. The transmission screen 4 of the present invention is made by assembling these minute elements in a plate shape such that the reflective wall is perpendicular to the plate surface or at an angle close to it. As the transparent material, air, resins such as acrylic resin, polycarbonate resin, transparent nylon, and transparent polyester, glass, and ceramics such as quartz and alumina can be used.

The reflective wall can be made of various metals including aluminum, nickel, silver, gold, chromium, titanium, and alloys thereof. A material with high reflectivity is used depending on the wavelength of the light used. It may also be one that has reflective properties due to the interference effect of a thin layer.

The angular relationship of the incident light and the outgoing light with respect to the transmission screen is shown in FIG. In Fig. 4, the refraction at the transparent body l is not shown because of the hour wheel design. The light beam 5 that has entered the plate surface at an incident angle of θ is reflected by the reflecting wall 1 and exits at an exit angle of ±θ. It is possible to prevent the deterioration of the image tone that occurs due to the horizontal arrangement of the cathode ray tubes shown in the figure.

As can be understood from Fig. 4, the condition is that the incident light flux undergoes at least one reflection, so we assume that the incident angle θ is large at the center of the screen and small at the outside.
When configuring a transmission screen with optical elements of the same shape, it is desirable that the distance in the direction of light travel is longer than the average size of the cross section on the incident side; however, on the axis, the light is incident in parallel. Since the emitted light does not move, but instead comes together from various directions, the emitted light has a distribution of exit angles as a result.

Figure 5 (a) is a three-dimensional representation of Figure 4, and Figure 5 To
), the distribution of light rays incident vertically at a certain angle of incidence using a rectangular micro element 31 becomes two vertically parallel linear scattered lights 33.

In order to distribute this in the entire viewing direction, it is necessary to
A square shape is better, so a circular shape is desirable.

This is shown in FIG. 5, where the scattered light 33 becomes circular.

An elliptical shape may be preferable because the direction of incidence of the principal light beam differs at each point on the transmission screen.

When the cross section of the reflecting wall is a straight line as shown in FIG. 4, the reflection is ideal n'. Assuming i reflection, ± for the angle of incidence θ
Therefore, in order to reduce the viewing angle dependence with a distribution of ±(θ±Δθ), it is desirable that the reflecting wall surface has undulations.

Therefore, a rough surface shows favorable results.

FIG. 6 shows a preferred cross-section of the plate. The cross section 40 on the cathode ray tube side is configured to be a flat surface with no irregularities in order to prevent the amount of incident light from decreasing due to the steps of the minute elements. On the other hand, the cross section 41 on the viewer's side is formed as a stepped surface with unevenness to prevent external light and illumination light from entering the screen.

In FIG. 7, the cross section of the exit side of the micro element is made convex in order to further expand the angle of the output light than the angle of the incident light. This configuration further improves viewing angle dependence.

Furthermore, by including transparent fine particles, microbubbles, etc. having a different refractive index from that of the transparent body inside the transparent body of this microelement, the dependence of the incident light on the incident angle can be further reduced. The transparent fine particles may be made of a transparent material such as resin particles, glass particles, titanium oxide particles, silica particles, alumina particles, or the like.

The space between the minute elements may be transparent or opaque, but it is not a main component of the present invention.

Effects of the Invention As described above, the present invention provides transparent microelements having reflective walls around them in a plate shape such that each reflective wall is arranged at an angle perpendicular to or close to a plane on the side from which light is emitted. By configuring this, a luminous flux in which light is always scattered around a line segment perpendicular to the exit side plane is provided, regardless of the angle of the incident light, without using a means for obtaining a parallel luminous flux such as a Fresnel lens. The effect of significantly improving viewing angle dependence can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the basic configuration of the present invention, Fig. 2 is a principle diagram of a conventional transmissive screen, Fig. 3 is an explanatory diagram of color tone deviation, which is a drawback of the conventional transmissive screen, and Fig. 4 is a diagram showing the principle of a conventional transmissive screen. An explanatory diagram showing how the incident light is diffused on the output side due to multiple reflections, Figure 5 (al, (bl) is an explanatory diagram showing the shape of the scattered light of the output light due to the difference in the cross-sectional area of minute elements. Cross-sectional view showing the difference in unevenness of the planes on the incident side and the output side, No. 7
The figure is a cross-sectional view when the shape of the optical minute element on the output side is convex. 1... Transparent material, 2... Reflective wall, 3
...Minute element, 4...Transmissive screen, 5...Incoming light flux, 6.6゛...Outgoing light flux, 1)...・Blue cathode ray tube, 12...
...green cathode ray tube, 13...red cathode ray tube, 14.17...blue light, 15.18...
... Green light, 16.19 ... Red light, 20.
... Transmissive screen, 21 ... Incident light flux, 22 ... Parallel light, 23 ... Outgoing light, 24 ... Fresnel lens, 25・・・・・・
Lenticular lens, 26...Convex cylindrical lens, 31...Minute element, 32...
...Incoming light, 33...Scattered light, 40...
... Plane on the incident light side, 41... Plane on the output light side, 4
3... Plane on the incident light side of the micro element, 44...
...The plane on the output light side of the microelement.

Claims (1)

[Claims] (1) A transparent microelement having a reflective wall around the periphery is configured in a plate shape such that the reflective wall is arranged at an angle perpendicular to or close to a plane on the side from which light is emitted. A transparent screen characterized by being a board. (2) A microelement with an average aspect ratio of 1 or more, an optical reflective layer on the longitudinal sidewall, small surface roughness on the other two end faces, and a transparent interior, whose reflective wall allows light to pass through. A transmission screen characterized in that it is a plate configured in a plate shape so as to be arranged at an angle perpendicular to or close to a plane on the side from which light is emitted. (3) The microelement has a round, polygonal, or distorted round cross section, is in the shape of a chip that is longer than the average cross-sectional diameter, and has a structure in which an optical reflective layer is provided on the long side wall. A transmission screen according to claim 1 or 2, characterized in that: (4) The transmission screen according to claim 1 or 2, wherein the reflective wall has a rough surface or undulations. (5) A transmission type according to either claim (1) or (2), characterized in that one side of the plate is flat with no unevenness and the other side is formed with unevenness. screen. (6) One of the end faces of the microelement has a convex shape or a convex lens, and the other end is a flat surface, according to either claim (1) or (2). Transparent screen as described. (7) The micro-elements include transparent fine particles, micro-bubbles, etc. to further improve the light-diffusing effect, according to either claim (1) or (2). Transparent screen.