JPS603617A - Back projection screen - Google Patents

Abstract

PURPOSE:To improve the contrast by forming a light absorbing layer on the surface of an observation side to which a light made incident from a light source side does not pass through. CONSTITUTION:As for a screen 1, its base material is constituted of a synthetic resin material having a good light transmitting property such as a methacryl resin, and on the light source side A of this screen 1, a lenticular 3 is formed in the horizontal direction, and on an observation side B, a lenticular 2 of a vertical direction orthogonal to said lenticular is formed. A light absorbing layer 4 is formed on the surface which a light in the lenticular 3 of a vertical direction of this observation side B does not transmit through. According to such a constitution, the view range of a vertical direction and a horizontal direction can be expanded by an operation of the lenticular of the horizontal direction and the lenticular 2 of the vertical direction, but in this case, the view range of the vertical direction is smaller than that of the horizontal direction, therefore, it is unnecessary to make the thickness of the screen so small, and also the forming surface of the light absorbing layer 4 can be made as large as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rear projection screen that has a wide vertical and horizontal viewing range and excellent contrast.

Rear projection screens used in video projection televisions and the like are desired to be bright, have a wide viewing range, and have high contrast so that images can be observed even in bright rooms. Generally speaking, for this type of screen, the horizontal observation area is made large and the vertical observation area is made small, considering the efficient distribution of light. Lens Sea If
In addition to widening the field of view in the horizontal direction, methods of providing fine irregularities on the surface or mixing a diffusing agent in the vertical direction have been adopted. In order to improve the contrast, for example, as seen in Japanese Patent Publication No. 52-46695, a light absorbing layer is provided on the opposite surface of the lenticular lens where light does not pass therethrough.

By the way, as shown in FIG. 1, the lenticular lens (a) is
The thickness of the base material is regulated by the width of the lenticular because the original light is focused once on the O-plane and then emitted, and in order to spread the light sufficiently in the horizontal direction, the thickness of the screen and the width of the lenticular lens must be adjusted northward. Must be So1 F! It won't happen. If the width of the lens was made smaller in order to maintain this ratio and improve resolution, the thickness of the screen would become dramatically thinner, which would cause the screen to warp and restrict mounting methods. Note that εj (←) in Figure 1 is a light absorption layer. In addition, when using such a lenticular lens, a shift in the point occurs due to the difference K in the angle of incidence of the three projection tubes, which is the case with a glojection television that uses a large number of projection tubes. The opaque part of
tυ4 where rBJs with ξ convergence layer cannot be made too large
In order to improve such conventional lenticular lenses, the applicant has decided to completely reflect a part of the light that enters the screen from the light source on a part of the vertical lenticular lens, and reflect it to the viewing side. proposed to expand the viewing angle by emitting light from
l) P;::i No. 1984-91896, patent application No. 1983-2
917 i8 and Japanese Patent Application No. 57-59389). By adopting a unique lenticular structure like this □, the horizontal viewing angle can be dramatically expanded, but it is not possible to expand the entire vertical viewing range.Generally, it is difficult to form a diffusing agent layer. There is no choice but to compensate for this by completely mixing in the diffusion agent.The present inventors have attempted to improve these points, and have formed a light absorption layer on the observation side, and made this surface as large as possible. We are trying to provide a screen that can do this. That is, the gist of the present invention is that a horizontal lenticular is formed on the light source side and a vertical lenticular that is orthogonal to this is formed on the observation side, so that light incident from the light source side does not pass through. A rear projection screen is characterized in that a light absorption layer is entirely formed on the viewing side surface.

Hereinafter, the present invention will be explained with reference to the drawings of the embodiments from FIG. 2 onwards.

In FIG. 2, (1) is a screen, and its base material is usually made of a synthetic resin material with good light transmittance, such as methacrylic resin, polycarbonate resin, or vinyl chloride resin. Lateral lenticules (6) are formed on the light source side (A) of this screen (1),
In the present invention, the light in the vertical lenticule (3) on the JI festival side (B) is formed. A light absorption layer (4
) '(It is characterized by a c-type FV.

If this 47', J configuration is used, it is possible to expand the field of view in the σ1 direction and the horizontal direction due to the action of the lateral lenticular (3) and the tq7 direction lenticular (2). When the vertical viewing range is
Since it is smaller than that in the horizontal direction, there is no need to reduce the thickness of the screen so much. - When the light absorption layer (4) is provided like this, Observation 1j:l! C
There is an advantage that the entire portion of the surface (10) through which light does not pass can be utilized effectively, and that the formation of the light absorption layer (4) can be made much larger. In addition, the light absorption layer (
4)? The forming method may be a screen printing method, a painting method, or a photographic method using a photosensitive agent.

FIG. 3 shows another embodiment of the present invention.
A lens (21) having a total reflection surface as a lenticular (2) in I (B) and a total reflection surface? This is an example in which lenticules (22) that do not have one are alternately arranged.

Also, No. 41￥1 is another practical example using a vertical lenticular cz)ffi with a total reflection surface, but in this case, the lenticular (2) in the node 1 direction has total reflection surfaces on both sides. Then, the lens surface is shaped between the total reflection surfaces.
ff1z: L lens (23) k was used. When such a lens (23) f is used, a valley is formed between the lenses that are in contact with each other, and this valley becomes a part where light does not pass through. Therefore, as shown in FIGS. This means that the light absorbing layer (4') can be filled in and added to the other light absorbing layer (4), and the ratio of the light absorption layer (4) on the observation side (B) can be further increased. be.

The effect of such a total reflection surface will be explained based on FIG. 8. This example is similar to FIG. ) are arranged alternately. And this lens (
21) The element (XI) l (Xdij:, C'A') which is totally reflected from the circular top surface (21b) out of the C incident on the total reflection surface (21a), (X2
The light is emitted from the center and further away. This emitted light (xl′
), (X2 directly approaches the expansion of the viewing angle, but in this example, 'T' means that the light (Y) incident on the circular top surface (21'b) is c as in a general circular lens. , y/), and exits to a location near the center (') of this element (Y')ij Niscreen.Also, the circular lens (22) with the alternating VC array 8 is similar to the general case. Since it is diffused in the horizontal direction, the ratio of 1/integular (2
), the origin of cAL et al. is located over a fairly wide range from the center of the sewing table L-r-, and the β value is about 30 to 45 degrees. You can expand your benevolence. p1 total reflection ihj (21a) y
The inclination of the total reflection surface in the lens (2) can be 74'7 from the refractive index of the material used and Snell's equation, but when using methacrylic resin, the inclination (the inclination is 70 to 80 degrees) As explained above, the vertical lenticular (2) in the present invention contributes to expanding the horizontal viewing angle of the screen (1), but the vertical lenticular (2) contributes to expanding the horizontal viewing angle of the screen (1). Since it is not possible to expand the field of view in the direction, in the present invention, the screen (1)
The main feature is that the lateral lenticules (3) are completely formed on the light source side (A) of the light source side (A). With this configuration, the light source fI! (A) [Also, since the light is first spread vertically by the lateral lenticule (3) and then spread horizontally as shown in Figure 8,
Lateral viewing range? This means that it can be expanded at the same time. In addition, in the present invention! A lens (with a total reflection surface (21a) inside the lenticular (2) in one direction
The width of the lens (21) is preferably about 0.3 to 0.6 mm, and the width of the circular lens (22) is preferably about 16 to 0.9 rtv. Also, on the light source side (horizontal lenticular (3)
) has a width of 02 to 0.5 m and 8 degrees. For example, when using a lenticular ffi with a circular cross section, it is preferable that the ratio of width to bending radius is 1.0 or less.

FIG. 7 shows an actual example in which a separate circular Fresnel lens (5) 'Ii= is arranged in the present invention.
In this way, the circular Fresnel lens can evenly brighten the screen to the corners, which is more effective, but it is also possible to place it upside down on the surface of the Fresnel lens (5). .

The rear projection screen of the present invention may be constructed of transparent materials as described above, but may also supplementally use a diffusing agent. That is, it is effective to uniformly mix the diffusing agent gold screen (1) K, but examples of the diffusing agent in this case include, for example, S i 02 , Ca (!QI).

An explosive type diffusing agent such as AtzO3, TiO2, BaSO4, ZnO, glass powder, or an organic type diffusing agent can be used.

In addition, in order to adjust the color tone of the screen, it is also effective to completely add dyes and pigments such as carbon black. ◎Furthermore, to reduce specular reflection on the surface, the surface on the light source side (A) and/or the viewing angle 1 (B) It is also effective to form all the fine irregularities. Since the present invention has the configuration as detailed above, the horizontal lenticular on the light source side and the vertical lenticular on the i side 4η
It is possible to expand the viewing range in the vertical and horizontal directions, and the contrast can be completely improved by the absorption layer provided on the observation side, and the surface on which the light absorption layer is formed is also made as thick as possible. There are advantages such as being able to

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional lenticular lens, and FIGS. 2 to 6 are partial perspective views showing embodiments of the present invention.
FIG. 7 is a partial perspective view showing an embodiment in which all separate Fresnel lenses are arranged, and FIG. 8 is an explanatory diagram of the transmission state of light in a vertical lenticular having a total reflection surface. (A)...Projection side CB)...Viewing side (1)...Screen (2)...Vertical lenticular (21)...
... Lens with a total reflection surface (5) ... Lateral lenticular (4), (4') ... Light absorption layer (5) @ O ... Fresnel lens book 1 diagram Book 5 stem 6171 #! -7 figure

Claims (1)

[Claims] 1. A horizontal lenticular is formed on the light source side, and a vertical lenticular perpendicular to the lenticular is formed on the observation side, and the observation side does not allow light incident from the light source to pass through. 2. A rear projection screen according to claim 1, characterized in that a light-absorbing layer is formed on the surface of the rear projection screen.2. 3. The rear projection screen according to claim 2, characterized in that a light absorption layer is formed in the valley between the adjacent total reflection surfaces of the lenticulars of vSl and Ill. 4゜ Screen base material Claim 1, characterized in that a diffusing agent is added to the rear projection screen IJ-05 according to Claim 2 or 3, wherein a light-absorbing dye and pigment is added to the base material of the screen. 6. A rear projection screen according to claim 1, 2, 3, or 4, characterized in that: The rear projection screen according to item 1, item 2, item 3, item 4, or item 5, characterized in that a projection screen is formed with unevenness. 7. A rear projection screen as claimed in claim 1, 2, 5, 4, 5 or 6, characterized in that it is arranged on a Fresnel lens of the body.