JPH04355442A - Transmission type screen - Google Patents

Abstract

PURPOSE:To provide a transmission type screen with which color dispersion can be improved largely, and which can be formed easily. CONSTITUTION:A transmission screen 10 is composed of a light control plate 12 for diffusing incident light from different angles almost in the same range, and a perpendicular lenticular lens sheet 14 for diffusing the light diffused almost in the same range by the light control plate 12 in a wire range. For example, in radiating each light of R(red), G(green), and B(blue) to a screen from three CRT's disposed at different positions, the light R, light G and light B are radiated at incident angles of -10 deg., 0 deg., and +10 deg. respectively, so the light are diffused by the light control plate 12 almost in the same range, and the light diffused almost in the same range can be further diffused by the lenticular lens sheet 14. As a result, a screen having no color dispersion and of a wide view can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmissive screen, and particularly to a transmissive screen suitable for use in rear projection TVs and the like.

0002

2. Description of the Related Art Transmissive screens used in projection TVs and the like are required to diffuse incident light and reduce interference from external light to obtain images with good contrast.

[0003] A transmissive screen that satisfies these requirements has a lenticular lens formed on the light entrance side.
In addition, a lenticular lens with a black stripe is known in which a light shielding portion is formed in a non-light emitting portion on the light emitting side.

For example, the above-mentioned lenticular lens with a black stripe is used as a transmission type screen, and three CRs of red (R), green (G), and blue (B) are used as projection tubes.
In projection TV using T (cathode ray tube), R
, G, and B are projected from projection tubes placed at different positions, so they are projected onto the screen at different angles. As a result, there is a problem in that color unevenness (so-called color shift) occurs when the screen is viewed from an oblique direction.

That is, as shown in FIG. 9, which shows the configuration of a projection TV using three R, G, and B CRTs as projection tubes, each of the R, G, and B lights is projected from a different position. The light enters the screen 10 at a specific angle. In this way, since the incident angles of the R, G, and B lights are different, the spread of the light emitted from the screen is also different for each color, and as a result, it is visually recognized as color unevenness.

In FIG. 9, for example, G light is projected perpendicularly onto the screen from the CRT (G), R light is projected from the CRT (R), and B light is projected from the CRT (B).
Screen 10 so as to form an angle of ±10° to the light.
When the screen 10 has a horizontal half-value angle of 25 degrees, the spread of each of the R, G, and B lights emitted from the screen 10 is shown in the diagram in FIG. . This diagram shows the light intensity distribution as a triangle, but this representation does not lose its generality, and in many cases it can represent the characteristics of the screen with a good approximation. .

As shown in FIG. 10, as described above, the G light is incident perpendicularly to the screen 10, and the R light and B light are incident at an angle of 10° from opposite sides to the horizontal direction. Therefore, the spread of R light and B light emitted from the screen 10 deviates from the spread of G light, and these R light,
The intensity peaks of the B light are shifted by 10 degrees in opposite directions from the peaks of the G light.

As described above, since the spread of the emitted light is different for each color, when the screen 10 is viewed from an oblique direction of, for example, about 20 degrees, the ratio of the intensity of the B light to the intensity of the R light is 2.
Since it is twice as large, the screen 10 will appear blue. This phenomenon is so-called color shift.

[0009] As a transmission type screen for reducing the color shift described above, lenses are formed on the light entrance side and the light exit side of the screen, and the spread of R light and B light is brought closer to the spread of G light by the lens on the light exit side. Corrected double-sided lenticular lens sheets are known.

0010

[Problems to be Solved by the Invention] However, it is impossible to completely eliminate color shift by correction using lenses formed on a screen, such as the above-mentioned double-sided lenticular lens sheet. When the B light is incident on the screen at an incident angle of ±10°, the limit is to reduce the intensity ratio of the R light and the B light to at most twice over the entire range of light spread.

Further, the double-sided lenticular lens sheet as described above is difficult to manufacture because strict positional accuracy and thickness accuracy are required between the lenticular lenses formed on the light entrance surface and the light exit surface, respectively.

Furthermore, it is necessary to form the light exit surface near the focal point of the lenticular lens on the light entrance side, but as the pitch of the lenticular lens becomes smaller, the thickness of the sheet becomes thinner. It is difficult to create a sheet in which lenticular lenses are formed with pitch, and in particular, it is extremely difficult to create a sheet by extrusion molding.

The present invention has been made to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a transmission type screen in which color unevenness is significantly improved and which can be easily produced.

[0014]

[Means for Solving the Problems] The present invention provides a light control layer that diffuses light incident at different angles into substantially the same range, and a light control layer that diffuses light incident at different angles into substantially the same range. The above object has been achieved by including a diffusion layer that diffuses light over a wide range.

[0015]

[Operation] In the present invention, for example, as shown in FIG. 9, from three CRTs arranged at different positions, R,
When each of the G and B lights is incident on the screen at different angles, the light control layer can diffuse each of the R, G, and B lights into approximately the same angular range.
It is possible to align the directions of each light, and by inputting these lights whose directions have been aligned by the light control layer into the diffusion layer, it is possible to diffuse them over a wider area and then emit them from the screen. Therefore, it is possible to form a screen with almost no color shift and a wide viewing range.

Furthermore, the transmission type screen of the present invention does not require highly accurate positioning unlike the double-sided lenticular lens, so it can be easily produced.

[0017]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic perspective view showing a transmission type screen according to a first embodiment of the present invention. The arrow in the figure indicates the direction of light incidence.

The transmissive screen 10 of this embodiment has a light control plate (light control layer) 12 disposed on the incident side, and on the light output side, the light emitted from the light control plate 12 is spread over a wide range in the horizontal direction. Vertical lenticular lens sheet that can be expanded (
A diffusion layer) 14 is arranged. In the transmission type screen, a light diffusing agent may be contained inside the vertical lenticular lens sheet 14 in order to spread light also in the vertical direction.

The light control plate 12 is not particularly limited as long as it has the function of diffusing light incident at different angles into substantially the same range;
A plastic sheet containing minute interfaces with different refractive indexes and directionality, as disclosed in US Pat. No. 77,001, can be used. Such a light control plate is used to control the direction of light irradiation when photopolymerizing a composition that is a mixture of a photopolymerizable high refractive index monomer (or oligomer) and a photopolymerizable low refractive index monomer (or oligomer). It can be formed by regulating the refractive index of the resin mixture to give directionality to the arrangement of the refractive index.

The light control plate has an optical property of selectively scattering only light incident at a specific angle.

As a result of various studies on similar light control plates, the present inventor found that the light control plate has a characteristic of diffusing light incident from different angles into substantially the same range. A specific example of its characteristics will be shown below.

FIG. 2 shows R, G
, and B at −10°, 0°, and +10°, respectively.
This figure shows the intensity distribution of each light emitted from the light control plate when the light is incident at an incident angle of . In addition, in the figure, R
Light is shown by a solid line, G light by a broken line, and B light by a chain line.

As is clear from FIG. 2 above, it can be seen that the light incident at different angles of incidence is diffused within the approximately same range of ±20°.

However, although the light control plate described above diffuses light in approximately the same area, there are areas where the intensity of the light is extremely strong, so it cannot be used alone as a screen.

Therefore, as in this embodiment, a vertical lenticular lens sheet (
By disposing the diffusion layer (14) on the output side of the light control plate 12 and spreading each light horizontally over a wide range with uniform intensity, it is possible to create a screen with no color shift and a wide field of view. It is something.

[0027] Furthermore, the lenticular lens sheet 14
By incorporating a light diffusing agent into the lens, the field of view can also be expanded in the vertical direction.

FIG. 3 is a schematic perspective view showing a second embodiment of a transmission screen according to the present invention.

The transmissive screen 10 of this embodiment has a vertical lenticular lens (diffusion layer) 16 directly formed on the light output side of the light control plate 12 to form an integral structure. In addition to the effects of the first embodiment, this transmissive screen has the advantage that it is easy to handle because of its integral structure and can also be made thin.

FIG. 4 is a schematic perspective view showing a transmission type screen according to a third embodiment of the present invention.

The transmission type screen 10 of this embodiment is the same as that of the first embodiment except that the lens surface of the vertical lenticular lens sheet 14 is directed toward the light control plate 12 and the direction of the lenticular lens sheet 14 is reversed. It is the same as the transmission type screen.

According to this embodiment, similarly to the first embodiment, it is possible to form a transmissive screen that does not cause color shift and has a wide field of view.

FIG. 5 is a schematic perspective view showing a transmission type screen according to a fourth embodiment of the present invention.

The transmissive screen 10 of this embodiment is the same as the transmissive screen of the third embodiment, except that a light shielding portion (black stripe) 18 is formed in the non-light emitting portion of the light emitting surface of the vertical lenticular lens sheet 14. The structure is as follows.

According to this embodiment, in addition to the effects of the third embodiment, contrast can be improved.

FIG. 6 is a schematic perspective view showing a transmission type screen according to a fifth embodiment of the present invention.

The transmission screen 10 of this embodiment has a horizontal lenticular lens 20 for vertically diffusing light on the incident side of the light control plate 12, and a vertical lenticular lens 16 and the horizontal lenticular lens on the light exit side. A light shielding part 18 is formed at a position corresponding to the non-light emitting part of 20.

According to this embodiment, the field of view can be expanded not only in the horizontal direction but also in the vertical direction, and the contrast can be improved.

FIG. 7(A) is a schematic perspective view showing a light transmitting screen according to a sixth embodiment of the present invention, and FIG. 7(B) is an enlarged partial sectional view thereof.

The transmission screen 10 of this embodiment does not use a lenticular lens sheet or a lenticular lens as a diffusion layer, but uses a light exit surface of the light control plate 12 as a minutely uneven surface 22, and uses the uneven surface 22 as a diffusion layer. This is what I did.

According to this embodiment, there is an advantage that a transmission type screen can be formed with an extremely simple structure.

Next, specific examples will be shown to clarify the effects of the present invention.

Lumisty (trade name) manufactured by Sumitomo Chemical Co., Ltd. is used as the light control plate, and the Lumisty is placed on the light incident side, with a pitch of 1.0 mm and a shape of 0.55 mm.
A transmission type screen corresponding to the third embodiment (FIG. 4) was prepared by arranging a lenticular lens sheet in which a lenticular lens of R was formed on the light output side.

The transmission screen and the three CRTs R, G, and B are used as projection tubes, and as shown in FIG. When a projector device was created in which the incident angles of each of the B lights were −10° and +10°, image light having the light intensity distribution shown in FIG. 8 was obtained. That is, a good image with almost no color shift (intensity ratio of R light and G light of 1.1 or less) was obtained within a range of approximately ±60° in the horizontal direction from the center of the screen.

Although the present invention has been described in detail above, the present invention is not limited to what has been shown in the above embodiments, and can be modified in various ways without departing from the gist thereof.

[0046]

As explained above, according to the present invention, it is possible to provide a transmission type screen in which color unevenness (color shift) is greatly improved and which can be easily produced.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing a transmission screen according to a first embodiment of the present invention.

FIG. 2 is a diagram showing optical characteristics of a light control plate.

FIG. 3 is a schematic perspective view showing a second embodiment of a transmission screen according to the present invention.

FIG. 4 is a schematic perspective view showing a transmission screen according to a third embodiment of the present invention.

FIG. 5 is a schematic perspective view showing a transmission screen according to a fourth embodiment of the present invention.

FIG. 6 is a schematic perspective view showing a transmission screen according to a fifth embodiment of the present invention.

FIG. 7 is a schematic perspective view and an enlarged partial sectional view showing a transmission screen according to a sixth embodiment of the present invention.

FIG. 8 is a diagram showing an example of optical characteristics of a transmission screen according to the present invention.

FIG. 9 is a schematic explanatory diagram showing the arrangement of a screen and a projection tube.

FIG. 10 is a diagram showing conventional problems.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10... Transmissive screen, 12... Light control board, 14... Vertical lenticular lens sheet, 16... Vertical lenticular lens, 18... Light shielding part, 20... Horizontal lenticular lens, 22... Uneven surface.

Claims (1)

[Claims] 1. A light control layer that diffuses light incident at different angles into substantially the same range; and a diffusion layer that diffuses the light diffused into substantially the same range by the light control layer over a wide range. A transparent screen characterized by: