JP2947160B2 - Transmission screen - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmissive screen used for a rear projection type display device, and more particularly to a transmissive screen capable of obtaining a sufficient contrast and a good focus characteristic with a simple structure. .

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for displaying images on a large screen, and a rear projection display apparatus for enlarging and projecting the display content of a small liquid crystal panel built in a liquid crystal projector on the back of a transmission screen has been spreading. However, the projection type display device is a CRT (Cathode Ray Tube:
Although it is smaller and lighter than a direct-view display device using a cathode ray tube, it is currently inferior in brightness and resolution. Accordingly, transmission screens capable of improving the contrast and focus characteristics of a projected image have been actively developed.

[0003] As a conventional transmissive screen for improving contrast and focus characteristics, for example, there is one as shown in FIG. FIG. 3 is a partially enlarged view showing a conventional transmission screen.

In FIG. 3, a conventional general transmission screen is a first screen 2 which is a Fresnel screen.
0 and the second screen 1 which is a lenticular screen
It consisted of ten. The second screen 110 had a configuration in which a light non-transmissive portion 112 called a black stripe was provided on the surface of a screen substrate 111 in which lenticular lenses 111a and 111b were formed in rows on the front and back surfaces. Further, the screen base material 111 was formed of a transparent acrylic resin, and the light diffusing material 113 colored in black, blue, or the like was compounded throughout.

In the conventional transmissive screen having the above structure, the provision of the light non-transmissive portion 112 reduces the reflectance of external light incident from the screen surface side, and the light diffusing material 113 is colored. Thus, the contrast of the projected image is improved by lowering the black level of the image.

Here, the light diffusing material 113 has a function of diffusing the projection light 11 from a liquid crystal projector (not shown) in the horizontal and vertical directions to widen the viewing angle of the projected image. However, when such a light diffusing material 113 is blended into the screen substrate 111, the projection light 11 is diffused before focusing on the surface of the screen substrate 111, and the image of the focal point on the screen substrate 111 is blurred. However, there is a problem that the focus characteristics of the projected image are deteriorated.

Therefore, Japanese Patent Application Laid-Open No. 4-322240 discloses that
As shown in FIG. 4, a transmission screen has been proposed in which a light diffusion layer 114 in which a light diffusion material 113 is mixed is formed between the light opaque portions 112 of the screen substrate 111. . In this transmission screen, the projection light 11 after focusing on the surface of the screen substrate 111 is
The focus characteristic of the projected image is improved by diffusing the light in the horizontal direction and the vertical direction by the light diffusion layer 114.

[0008]

However, in the conventional transmission screen shown in FIGS. 3 and 4, the second screen 11 is not used.
Since the light non-transmissive portions (black stripes) 112 are provided on the screen base material 111 and the light diffusing material 113 is colored, the projection light 11 transmitted through the screen base material 111 is , Light diffusion material 113
However, there is a problem in that the light is absorbed by the colorant and the light use efficiency is poor. For this reason, the brightness of the projected image is reduced as a whole, and the contrast of the projected image cannot be effectively improved.

Further, the light opaque portion 112 easily interferes with a lattice of a liquid crystal panel built in the liquid crystal projector to cause interference fringes (moire).
Lenticular screen 11 according to the pixel of the liquid crystal panel
It was necessary to make the screen pitch of 0 fine. However, when the screen pitch of the lenticular screen 110 is reduced, the light opaque portion 112 and the light diffusion layer 114
In order to form the light-transmitting screen with high precision, it is difficult to improve the focus characteristics by the light diffusion layer 114 in the transmission screen shown in FIG. Especially,
In the high-definition liquid crystal projector, since the pixels of the liquid crystal panel are very fine, it is extremely difficult to form the light opaque portion 112 and the light diffusion layer 114 with high precision.

Further, in a conventional transmission screen, each of the lenticular lenses 11 on both sides of a screen substrate 111 is used.
The lenticular lenses 111a and 111b are made of acrylic resin, which has a high acidity, corrodes the mold when the screen substrate 111 is formed, and shortens the life of the mold. There was a problem of doing.

Further, in the transmission screen shown in FIG. 3, the light diffusing material 113, which is a glass-based fine particle, is blended into the entire screen substrate 111. Therefore, when forming the lenticular lenses 111a, 111b, There is also a problem that the diffusion material 113 damages the mold.

Although not a transmissive screen, Japanese Patent Application Laid-Open No. Hei 4-63333 discloses a polarizing screen for a liquid crystal projector in which a polarizing plate having a transmittance curve that is the same as or similar to the wavelength characteristics of the three primary colors of the liquid crystal projector is arranged on the screen surface. Had been proposed. However, such a polarizing screen does not solve the above problems at all, and even if the polarizing plate is directly applied to a transmission screen, external light is reflected on the surface of the polarizing plate, There has been a problem that reflection of illumination or the like occurs on the screen.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple structure, can provide a sufficient contrast and a good focus characteristic, and has a mold for forming a screen. It is an object of the present invention to provide a transmission screen that can extend the life of the screen.

[0014]

To achieve the above object, a transmission screen according to the present invention is a transmission screen of a rear projection display device which enlarges and projects an image of a liquid crystal projector from the rear side of the screen to form an image. A transparent substrate serving as a base material of a screen, a polarizing sheet bonded to the surface side of the transparent substrate, the polarizing sheet having a polarization axis in the same direction as the polarization axis of projection light of the liquid crystal projector, and a transparent sheet covering the surface of the polarizing sheet. A reflective coat and the transparent substrate
Thin sheet containing uncolored light diffusion material bonded to the back side
A light-diffusing sheet in the shape of
The lenticular lens array made of UV-cured resin
Anti-reflection coating formed on the back side of the lenticular lens array
And a configuration including

According to such a configuration, the configuration is simple.
Good contrast and good focus characteristics
Can be obtained and also for forming the screen
The life of the mold can be extended.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a transmission screen according to the present invention will be described with reference to the drawings. First, the transmission screen according to the first embodiment of the present invention will be described. FIG. 1 is an explanatory diagram showing a transmission screen according to the first embodiment of the present invention.

In FIG . 1, the transmission screen 40 of the present embodiment includes a first screen 20 which is a Fresnel screen and a second screen 30 which is a lenticular screen.

[0018] On the surface (exit surface of the projection light) of the second transparent substrate 31 as a base material of the screen 30, the polarizing sheet 32 having a polarization axis in the same direction as the polarization axis of the projection light 11 of the liquid crystal projector 10 is bonded I have. Here, the arrow A indicates the direction of the polarization axis of the projection light 11, and the arrow B indicates the polarization sheet 32.
Shows the direction of the polarization axis. Further, as shown by an arrow C, the external light such as the illumination 50 is random light. The polarizing sheet 32 contains iodine and the like, and has a black color, a dark green color, and a dark blue color as a whole.

Meanwhile, on the back of the transparent substrate 31 (the incident surface of the projection light), the light diffusing sheet 33 and the light diffusing material 33a unpigmented blending the entire Yes bonded, this light diffusing sheet 33
A lenticular lens array 34 made of an ultraviolet curable resin is formed on the back surface of the lens. Further, the surface of the polarizing sheet 32 is covered with a non-reflection coat 35a, and the ultraviolet curable resin lenticular lens array 34 is covered with a non-reflection coat 35b.
Covered by.

The liquid crystal projector 10 has a built-in liquid crystal panel (not shown), and the image information displayed on the liquid crystal panel is enlarged and projected from the rear side of the transmission screen 40.

In the transmissive screen 40 of the present embodiment having the above-described configuration, the projection light 11 emitted from the liquid crystal projector 10 is incident on the first screen 20 which is a Fresnel screen, and is converted into a substantially parallel light beam. The light is emitted to the back (incident surface) side of the second screen 30. Then, the projection light 11 emitted to the second screen 30 side is
All light is incident on the second screen 30 without being reflected by the non-reflection coat 35b.

The projected light 1 incident on the second screen 30
Numeral 1 is condensed by the lenticular lenses forming the UV curable resin lenticular lens array 34, focuses on the surface (outgoing surface) of the transparent substrate 31, and forms an image.
Further, when the projection light 11 passes through the light diffusion sheet 33, it is diffused in the horizontal and vertical directions by the light diffusion material 33a blended in the light diffusion sheet 33. Thereby, the projection image of the liquid crystal panel is displayed on the surface of the transparent substrate 31.

[0023] After that, all, the projected light 11 is polarizing sheet 3
2 and the non-reflection coat 35a, and are emitted to the observer side. In addition, reflection of external light (arrow C) on the surface side of the transparent substrate 31, that is, illumination 50 on the screen is performed by the non-reflection coating 35 a covering the surface of the polarizing sheet 32.
Is prevented from being reflected.

[0024] Such, according to the transmission type screen of the present embodiment, the polarizing sheet 32, can be transmitted to the observer side without attenuating all of the projection light 11 which is incident on the transparent substrate 31, Further, the transparent substrate 31 is provided by the anti-reflection
The reflection of external light on the front surface side can be reliably prevented. Therefore, the light use efficiency is improved, and the contrast of the projected image can be effectively improved.

Further, by covering the UV curable resin lenticular lens array 34 with the anti-reflection coat 35b, the reflection of the projection light 11 on the incident surface side of the transparent substrate 31 can be prevented, thereby increasing the light use efficiency. Improve,
Further, the contrast of the projected image can be improved.

Furthermore, the light diffusing sheet 33, i.e., by which a light diffusing material 33a and thin sheet, it is possible to reduce the thickness of the imaging portion of the projection light 11, to improve the focusing characteristics of the projected image Can be. In addition, the light diffusion sheet 33 in which the light diffusion material 33a is formed in a thin sheet shape.
Is easy to handle during the manufacture of the screen,
As a result, the screen assembling efficiency can be improved and the cost can be reduced.

[0027] Furthermore, it is possible to prevent the reflection of external light by the non-reflection coating 35a, the light diffusing material 33a to be incorporated in the light diffusion sheet 33 may be a non-colored, the absorption of the projection light 11 by coloring Can be prevented. Thereby, the light use efficiency is further improved, and the contrast of the projected image can be improved.

On the other hand, since the lenticular lens array 34 is formed by ultraviolet curing resin, to prevent corrosion of the mold during the formation, it is possible to lengthen the mold life. Also, a lenticular lens array 34 made of an ultraviolet-curable resin is used.
Does not contain the light diffusing material 33a, so that the mold is not damaged.

Furthermore, such single-sided lenticular lens, since the shape is simple, it is possible to cope with the miniaturization, the occurrence of interference fringes in the high definition LCD projector (moire) can be easily prevented .

In the above embodiment, the light diffusion sheet 3
3 was bonded to the back side of the transparent substrate 31, that is, between the transparent substrate 31 and the lenticular lens array 34 made of an ultraviolet curable resin. However, the present invention is not limited to this. Transparent substrate 31 and polarizing sheet 3
2 may be joined. In the case of such a configuration, the projection light 11 after focusing on the surface of the transparent substrate 31 is used.
Can be diffused in the horizontal and vertical directions by the light diffusion sheet 33, so that the focus characteristics of the projected image can be further improved.

Next, the transmissive screen according to a reference embodiment of the present invention will be described with reference to FIG. FIG. 2 is an explanatory diagram showing a transmission screen according to a reference embodiment of the present invention.

[0032] Here, in the large screen and multi-screen screen or the like, creating the mold of these to fit the lenticular lens is very difficult, also, they are viewed from the vertical direction of the screen because it is a big screen In many cases, the vertical viewing angle characteristic and the horizontal viewing angle characteristic viewed from the side of the screen are almost the same. Therefore, an optimum viewing angle characteristic may be obtained only by the light diffusing material without using a lenticular lens for changing the vertical viewing angle characteristic and the horizontal viewing angle characteristic.

[0033] In FIG. 2, the transmissive screen of the present reference embodiment, which was applied to a such a large screen or multi-screen screen, transmissive screen 40 made of the ultraviolet curable resin from showing the present invention in FIG. 1 The lenticular lens array 34 is omitted, and the back surface of the light diffusion sheet 33 is covered with an anti-reflection coat 35b.

According to such a configuration, the present invention even when applied to a large screen or multi-screen screen, it is possible to obtain a sufficient contrast and good focus characteristics.

[0035]

As described above, according to the transmission screen of the present invention, it is possible to obtain a sufficient contrast and a good focus characteristic while having a simple structure.
The life of the mold for forming the screen can be extended.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a transmission screen according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a transmission screen according to a reference embodiment of the present invention.

FIG. 3 is a partially enlarged view showing a conventional transmission screen.

FIG. 4 is a partially enlarged view showing another conventional transmission screen.

[Explanation of symbols]

 Reference Signs List 10 liquid crystal projector 11 projection light 20 first screen 30 second screen 31 transparent substrate 32 polarizing sheet 33 light diffusion sheet 33a light diffusion material 34 ultraviolet curable resin lenticular lens array 35a, 35b non-reflective coating

Claims (1)

(57) [Claims] 1. A transmissive screen of a rear projection display device for enlarging and projecting an image of a liquid crystal projector from the rear side of a screen to form an image, a transparent substrate serving as a base material of the screen, and a surface joined to the transparent substrate. A polarizing sheet having a polarization axis in the same direction as the polarization axis of the projection light of the liquid crystal projector, a non-reflection coat covering the surface of the polarization sheet, and a non-colored light diffusing material bonded to the back side of the transparent substrate. Arrangement
Light-diffusing sheet in the form of a thin sheet combined with UV curable resin formed on the back side of this light-diffusing sheet
Lenticular lens row and the anti-reflection core formed on the back side of this lenticular lens row.
Transmission screen, characterized in that a chromatography bets.