JPH04270334A - Transparent projection screen - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission type projection screen used in a rear projection type projector or the like.

0002

2. Description of the Related Art Conventionally, this type of transmission projection screen is required to diffuse light and prevent reflection of external light to enhance contrast so that it can be observed from a wide range. In order to meet this requirement, a large number of horizontally diffusing lenticular lenses that condense light on the light input side and diffuse it horizontally are formed in parallel. Lenticular lens sheets with black stripes are widely used, which have light absorbing parts formed in non-light emitting parts to reduce the influence of external light while diffusing light.

[0003] Also, in a normal transmission type projection screen,
In the horizontal direction, there are many opportunities for observation from a wide range, and in the vertical direction, unless it is installed in a special location, it is not necessary to make the diffusion angle as wide as in the horizontal direction. Therefore, the horizontal diffusion is
30°~4 by horizontal diffusion lenticular lens
The diffusion angle is about 5 degrees, and the vertical diffusion is made to about ±10 degrees by kneading the diffusion material into the sheet base material.

0004

[Problems to be Solved by the Invention] In the conventional transmission type projection screen described above, in order to widen the light absorption area on the light output side, the light output surface is set near the light converging point of the lenticular lens, so the thickness of the lens sheet is should be approximately equal to the focal length. However, when using a liquid crystal panel as a light source or when projecting high-quality images such as high-definition, it is necessary to reduce the pitch of the lenticular lens (fine pitch), which requires light absorption on the light exit surface as in the past. In the case of a transmission type projection screen provided with a portion, there was a problem in that the thickness of the sheet became too thin and sufficient strength could not be obtained.

[0005] Further, the diffusing material for horizontally diffusing the light is small particles having a refractive index different from that of the sheet base material, and light is reflected and refracted at the interface between the sheet base material and the particles. However, since the diffusion material is randomly mixed into the sheet base material, if the amount of the diffusion material is increased to improve the diffusion properties,
There were problems in that the rate of light loss due to diffused reflection and the like increased and the resolution decreased.

[0006] The purpose of the present invention is to solve the above-mentioned problems,
To provide a transmission type projection screen which can obtain sufficient strength and thickness even if the pitch of lens parts on the light entrance side is reduced, has a wide light absorption part for preventing reflection of external light, and has good diffusion characteristics. That's true.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the transmission type projection screen according to the present invention has a light entrance side lens portion formed with a condenser lens for condensing and diffusing light on the light entrance side. and a light absorption part formed inside the part other than the part through which the light near the condensing point of the condensing lens passes, and a light output side lens part in which a diffusion lens for diffusing the light is formed on the light output side. There is a configuration that has.

[0008]

[Operation] According to the present invention, the light absorbing portion is formed inside the screen base material in a portion other than the portion through which light passes near the condensing point of the condensing lens, so that the overall thickness is reduced. It is possible to increase the thickness of the light absorbing portion and also increase the area of the light absorbing portion.

Furthermore, since lens portions are formed on both the light input side and the light output side to diffuse the light horizontally or vertically, there is no need to use a diffusing agent, which reduces light loss and resolution degradation. There is no.

0010

EXAMPLES The present invention will be explained in more detail below by way of examples with reference to the drawings and the like. FIG. 1 is a perspective view showing a first embodiment of a transmission type projection screen according to the present invention, and FIG. 2 is a side sectional view of the first embodiment.

In the transmission type projection screen 1 of the first embodiment, a large number of vertically diffusing lenticular lenses 11 are formed in parallel on the light incident side to condense light and diffuse it in the vertical direction. The shape of the vertical diffusion lenticular lens 11 may be any shape as long as it satisfies the required diffusion characteristics. For example, an array of circular, elliptical, or other shaped lenses may be used.

Further, as shown in FIG. 2, a vertical diffusion lenticular lens 1 is provided inside the transmission type projection screen 1.
A light-absorbing layer 12 is provided in the area near the condensing point of 1 where light does not pass through.
is formed. In other words, when light is focused by the vertically diffusing lenticular lens 11, near the focused position there is a band-shaped part where the light is focused and a part on a plane parallel to the vertically diffusing lenticular lens 11. Since there are horizontally alternating areas where the light does not pass through, the light absorption layer 12 is formed in the areas where the light does not pass through. Therefore, this light absorption layer 12 does not absorb the image light projected from the light source, but absorbs the external light from the viewing side, so it is possible to prevent the interference of the image due to external light and to prevent a decrease in contrast. can. In addition, since the light absorption layer 12 is inside, even if the pitch of the vertical diffusion lenticular lens 11 is reduced,
The overall thickness of the transmissive projection screen 1 can be increased.

On the light output side of the transmission type projection screen 1, a large number of horizontal diffusion lenticular lenses 13 for horizontally diffusing light are formed in parallel so as to be orthogonal to the vertical diffusion lenticular lenses 11. The horizontal diffusion lenticular lens 13 is preferably capable of diffusing light up to approximately ±60° in the horizontal direction, and its shape may be an array of circular, elliptical, or other shaped lenses. In addition, horizontal diffusion lenticular lens 1
By roughening the surface of No. 3, reflection of external light can be prevented.

The transmission type projection screen 1 of this first embodiment first has a vertical diffusion lenticular lens 1 on the light entrance side.
1 to the position where the light absorption layer 12 is formed, and the light absorption layer 12 is formed by positioning the vertical diffusion lenticular lens 11 on the sheet, and then the horizontal diffusion layer 12 is formed on the sheet. It can be manufactured by molding the portion B which becomes the lenticular lens 13.

In order to produce the sheet of part A, transparent resin such as acrylic resin, vinyl chloride resin, styrene resin, polycarbonate resin, etc. is injected using a mold formed with an inverse mold of the vertical diffusion lenticular lens 11. It may be formed by a molding method or the like. To form the light absorption layer 12,
It can be formed by printing or coating a sheet with ink containing a highly light-absorbing pigment. Furthermore, in order to form the horizontal diffusion lenticular lens 13 in the B portion, an ionizing radiation curing resin such as an electron beam curing resin or an ultraviolet curing resin is applied onto the light absorption layer 12 or in a mold that is an inverse mold of the vertical lenticular lens 13. Apply on top of
The sheet may be brought into close contact with a mold, irradiated with ionizing radiation such as electron beams or ultraviolet rays, cured, and then peeled off.

Next, further explanation will be given by giving specific manufacturing examples. According to the manufacturing method described above, the pitch P is formed on the light incident side.
1 = 0.3 mm, radius R1 = 0.33 mm, a vertically diffusing lenticular lens 11 is formed, and 60 mm is placed 1.0 mm from the peak of the vertically diffusing lenticular lens 11.
% of the light absorption layer 12 is formed, and a pitch P is formed thereon.
As a result of forming a horizontal diffusion lenticular lens 13 with R2 = 0.3 mm and radius R2 = 0.16 mm, and projecting an image by a liquid crystal panel that can combine red, green, and blue images and project them as a single light source, Bright, high-contrast, and high-resolution images could be observed within the range of ±40° in the horizontal direction and ±15° in the vertical direction. In addition, each lenticular lens 1
When the pitch of pixels 1 and 13 was set to 1/4 or less of the projection pitch of the pixels of the liquid crystal panel, no moiré occurred.

FIG. 3 is a perspective view showing a second embodiment of a transmission type projection screen according to the present invention. In the transmission type projection screen 2 of the second embodiment, a horizontal diffusing lenticular lens 21 is formed on the light entrance side, and a vertical diffusing lenticular lens 23 is formed on the light exiting side. Inside the transmissive projection screen 2, a light absorption layer 2 is provided in a portion where light does not pass near the convergence point of the horizontal diffusion lenticular lens 21.
2 is formed.

FIG. 4 is a perspective view showing a third embodiment of the transmission type projection screen according to the present invention, FIG. 5 is a side sectional view of the third embodiment, and FIG. 6 is a plan sectional view of the third embodiment. It is a diagram. As shown in FIG. 4, the transmission type projection screen 3 of the third embodiment has a vertically diffusing lenticular lens 31 formed on the light incident side, and a portion of the vertically diffusing lenticular lens 31 near the converging point where light does not pass through. , a light absorption layer 32 is formed.

In the transmission type projection screen 3 of the third embodiment, as shown in FIG. 6, a large number of parallel lenses 33 are provided on the light output side to completely reflect and diffuse the light. is formed. In this embodiment, high contrast can be obtained and light can be diffused up to approximately ±50°.

As another method for manufacturing the transmission projection screen of the present invention, the light-shielding portion corresponding to the light entrance side lenticular lens is formed on the surface of the base film while the base film is wound around the forming roll. The lenticular lens may be molded by forming a light shielding portion on the non-light condensing surface, and then the light-emitting side lenticular lens may be molded by an ionizing radiation curing resin method.

Furthermore, as another manufacturing method, as shown in FIG. 1, when forming a vertically diffusing lenticular lens on the light input side and a horizontally diffusing lenticular lens on the light output side,
A vertically diffused lenticular lens is molded using a thermoforming method such as extrusion molding, and the part that forms the light shielding part is made into a convex part.
A light-shielding material may be applied, and then the horizontal diffusion lenticular lens on the light output side may be molded using an ionizing radiation curing resin method. In this case, since the sheet of the vertically diffusing lenticular lens can be formed relatively thick with respect to the pitch, there is an advantage that thermoforming can be applied.

[0022]

As described above, according to the transmission type projection screen of the present invention, lenticular lenses are used in both the vertical and horizontal directions to diffuse light, and a light absorbing portion is provided between the vertical and horizontal lenticular lenses. This reduces the loss of light due to light diffusion, prevents reflection of external light, and allows high-contrast images to be observed from a wide range even in bright locations.

Furthermore, since the light absorbing section is provided inside the screen, even if the light absorbing layer is provided near the focal point of the light-incoming lenticular lens, it can have a sufficient thickness.

[Brief explanation of the drawing]

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

FIG. 2 is a side sectional view of the first embodiment.

FIG. 3 is a cross-sectional view of a second embodiment of a transmissive projection screen according to the present invention.

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

FIG. 5 is a side sectional view of the third embodiment.

FIG. 6 is a cross-sectional plan view of the third embodiment.

[Explanation of symbols]

1 Transmissive projection screen 11 Vertical diffusing lenticular lens 12 Light absorption layer 13 Horizontal diffusing lenticular lens 2 Transmissive projection screen 21 Horizontal diffusing lenticular lens 22 Light absorbing layer 23 Vertical diffusing lenticular lens 3 Transmissive projection screen 31 Vertical diffusing lenticular lens 32 Light Absorption layer 33 Total reflection lens

Claims (1)

[Claims] 1. A light input side lens part in which a condenser lens for condensing and diffusing light is formed on the light input side, and a part other than the part through which light near the condensing point of the condenser lens passes inside 1. A transmissive projection screen comprising: a light absorbing portion formed in a portion thereof; and a light exit side lens portion having a diffusion lens formed on a light exit side for diffusing light.