JPH0243529A - Transmission type screen - Google Patents

Abstract

PURPOSE:To obtain a transmission type screen excellent in contrast by constituting it of a total reflection surface capable of totally reflecting at least one part of incident light beams and of a linear Fresnel lens surface emitting most of the light beams being totally reflected on the total reflecting surface. CONSTITUTION:The linear Fresnel lens surface emitting most of the light beams totally reflected on the total reflection surface 1 is one of the elements to constitute the screen. The height of the lowest part 5 of a light beam outgoing part 2 can be equalized with the height of the highest part 4 of the total reflection surface so that a light absorbing coating film 3 can be formed on almost all the surface of the total reflection surface. The pitch of the linear Fresnel lens in a lenticular lens is desired to be the same pitch of the lenticular lens or less. Each tilt angle of the linear Fresnel lens is desired to be set so that incident light beams totally reflected on the total reflection surface and directly incident light beams can be simultaneously and sufficiently diffused. Thus, the transmission type screen excellent in the entire contrast can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-resolution transmission screen used in the optical and electrical fields.

(Prior art and problems) Transmissive screens, in which lenticular lenses are mounted on a light-diffusing resin substrate using a transparent resin mixed with fine particles having a different refractive index from the transparent resin, are widely used mainly in large displays. , has been applied in various fields.

With the recent demand for higher quality images in the market, there is a demand for transmission screens with relatively good contrast. In order to meet this demand, it is necessary to provide a light-absorbing coating on the viewing side, and especially in the case of a lenticular lens on the viewing side, it is necessary to provide a total reflection surface and apply a light-absorbing coating on that part. A method is being taken.

For example, when providing a light-absorbing coating on the total reflection surface of a lenticular lens having the shape shown in Japanese Patent Publication No. 61-28980 (Fig. 4), the simplest method is to apply the light-absorbing coating to the entire surface. However, there is a commonly used method in which the light-absorbing paint is then scraped off only at the light-emitting part using a squeegee or the like and cured to form a light-absorbing paint film. However, in the case of the lenticular lens having the shape shown in FIG. 4, the lowermost part 12 of the light emitting part 9 is located below the uppermost part 11 of the total reflection surface 8, so when forming a light-absorbing coating film by the above method, As shown in FIG. 4, it was only possible to form the light-absorbing coating 10 on the total reflection surface up to the same height as the lowest part 12 of the light emitting part.

Therefore, the area of the light-absorbing coating was small, and the contrast was insufficient.

(Means for Solving the Problems) The present inventors extensively studied the shape of the lenticular lens and found that if the lenticular lens on the observation side has a specific configuration, a transmission screen with excellent contrast can be obtained. This discovery led to the present invention.

That is, the present invention provides a transmission type screen having a lenticular lens on at least 12 viewing sides, wherein the lenticular lens has a total reflection surface that totally reflects at least a part of the incident light rays, and a total reflection surface that totally reflects the light rays on the total reflection surface. The present invention provides a transmission type screen characterized in that its constituent element is a linear Fresnel lens surface that emits most of the light.

FIG. 1 shows an optical path diagram of a lenticular lens of a transmission screen of the present invention, and FIG. 2 shows an example of a cross-sectional view. This is one aspect of the present invention and is not intended to limit the present invention.

In the present invention, by using a linear Fresnel lens surface as the surface that emits most of the light rays totally reflected by the total reflection surface 1, the lowermost part 5 of the light ray exit part 2 is placed at approximately the same height as the uppermost part 4 of the total reflection surface. Therefore, it becomes possible to form the light-absorbing coating film 3 on almost the entire surface of the total reflection surface,
It has become possible to increase the contrast of the entire screen.

In the present invention, there is no particular restriction on the pitch of the linear Fresnel lens in the lenticular lens, but from the viewpoint of image quality and efficiency,
Desirably 75 or less. In this case, the pitch may be uniform,
Furthermore, the pitch may be changed in order to provide a desired luminance distribution. There are no particular restrictions on the inclination angles of the linear Fresnel lens, but it is desirable to set them so that the incident light rays that are totally reflected on the total reflection surface and the directly incident light rays are simultaneously efficiently diffused.

In the present invention, the light emitting section may be composed of only a linear Fresnel lens as shown in FIG. 1, or may be combined with a convex lens as shown in FIG. 3.

In the present invention, it is desirable to incorporate a light diffusing agent into the substrate, and in this case, the average particle size of the light diffusing agent is 1 to 100 μm,
The blending amount is preferably 1 to 20% by weight.

There are no particular restrictions on the type of light diffusing agent; for example, inorganic types include calcium carbonate, barium sulfate, titanium oxide, silicon dioxide, calcium fluoride, talc, glass peas, etc., and organic types include styrene resin. , crosslinked polymers whose main components are methyl methacrylate/acrylic acid ester/aromatic vinyl monomer, etc., and any of them can be used alone or in combination of two or more. Among these, preferred are crosslinked polymers mainly composed of methyl methacrylate/acrylic acid ester/aromatic vinyl monomer with an average particle size of 3 to 100μ, calcium carbonate, quartz powder,
Barium sulfate and glass peas.

In the present invention, the transparent resin for the substrate is not particularly limited, and examples thereof include acrylic resin, styrene resin, polycarbonate, vinyl chloride resin, and the like. Among these, acrylic resins are preferred from the viewpoint of surface frostbite resistance, light resistance, transparency, and the like.

In the present invention, a rubber-like polymer may be added to the substrate in order to increase the impact resistance of the substrate. In this case, the blending ratio of the rubbery polymer is 1 to 50% by weight, and the average particle size is 0.05 to 10%.
0 μm is desirable.

In the present invention, it is particularly desirable to provide a light-absorbing coating on the viewing surface in order to improve contrast. There are no particular restrictions on the material and coating method of the paint, and for example, a paint containing black dye or black pigment may be used.

There are no particular limitations on the method of manufacturing the transmission screen of the present invention, and any conventional injection molding method, compression molding method, extrusion method, casting method, continuous casting method, photocuring method, etc. can be used.

When the transmission screen of the present invention is combined with a Fresnel lens, high performance can be obtained.

〔Example〕

The present invention will be specifically explained below using Examples, but these are not intended to limit the present invention.

(1) Synthesis of light diffusing agent particles The following compounds were charged into a reaction vessel equipped with a stirrer, a reflux condenser, and a nitrogen gas inlet.

Methyl methacrylate 55 parts by weight Butyl acrylate 20 parts by weight α-methylstyrene 25 parts by weight Allyl methacrylate
1.5 parts by weight t-dodecyl mercaptan
0.3 parts by weight Azobisisobutyronitrile 0.5 parts by weight Polyvinyl alcohol 3.0 parts by weight Water
After the inside of the 200 parts by weight container was sufficiently purged with nitrogen gas, the mixture of the above compounds was heated to 70'C with sufficient stirring to proceed with polymerization in nitrogen gas. After 4 hours, the temperature was maintained at 90°C for 1 hour to complete the polymerization. After the polymerization was completed, granular beads were obtained by dehydration, washing with water, and drying.

The obtained beads were sieved to have an average particle size of 35 μm and a refractive index of 1.
512 light diffusing agent particles were obtained.

(2) Substrate manufacturing Delbet ■70tl (Asahi Kasei ft1M>)
The light diffusing agent particles obtained in 1) were added at a ratio of 4% by weight, and after heating and kneading in an extruder (resin temperature 250°C), the molten resin coming out of the die was passed between rolls, cooled, and heated to 610X.
A substrate of 460 x 3 m was obtained.

(3) Molding of lenticular lenses and Fresnel lenses (2)! I! The substrate was placed between a lenticular lens mold having a cross-sectional shape as shown in FIG. 5 with a pitch of 1711111 per lenticular lens unit, a focal mold 11t1m, and a Fresnel lens mold with a pitch of 0.5m, and molded using a hot press. Temperature 180℃, molding time 10 minutes, molding pressure 3
After molding under the conditions of 0 Kg/cIi1, it was cooled with water for 5 minutes and taken out from the mold, and 1 q of screens for the example were obtained.

Further, for a comparative example, a mold for a lenticular lens having a pitch of 1 s+ and a cross-sectional shape as shown in FIG. 6 was used, and a screen for a comparative example was obtained in the same manner as described above.

(4) Formation of a light-absorbing coating film The toner (XER
(manufactured by OX Co., Ltd.) was applied, and the toner was scraped off only on the light emitting portion using a squeegee. Thereafter, the toner was fixed in a dryer at 80°C.

(4) The vertical projection length of the light-absorbing coating portion of the screens for evaluation examples and comparative examples was measured using a tool microscope.

Also, for the projector] ゛Former N CABIN 5UPER (Cabin Industrial lamp: 300-lens F3 f 50 m)
was used to project the images of the slides (bright coastal scenery) onto the transmission screens of the test examples and comparative examples, and the contrast of the images was visually determined.

(5) As a result, the vertical projection length of the light-absorbing coating film is 0.24AI in the example.
11, whereas in the comparative example it was 0.21 m.

Furthermore, the projected image of the slide appeared clearer in the example than in the comparative example.

〔Effect of the invention〕

The transmission screen of the present invention successfully forms a light-absorbing coating film on almost the entire surface of the total reflection surface, and has the effect that the contrast of the entire screen is extremely excellent.

[Brief explanation of the drawing]

FIG. 1 is an optical path diagram of the lenticular lens of the transmission screen of the present invention, FIG. 2 is a cross-sectional view of the lenticular lens, and FIG. , FIG. 4 is a sectional view of a conventional lenticular lens, FIG. 5 is a sectional view of a lenticular lens unit of an example, and FIG. 6 is a sectional view of a lenticular lens unit of a comparative example. Patent applicant Asahi Kasei Industries Co., Ltd. Agent Patent attorney Kazuya Nozaki Figure 1 Figure 2 1... Total reflection surface 2... Light II weight part 3... Light Film IR property tII[ 4...Top of total reflection surface 5...Top of light exit part 7...Convex lens 8... Total reflection part 9...Light S emission part 10...Light absorbing coating 11...Top part of total reflection surface 12...Light ray emission part bottom

Claims (1)

[Claims] 1. In a transmission screen having a lenticular lens on at least the observation side, the lenticular lens has a total reflection surface that totally reflects at least a part of the incident light beam, and a linear Fresnel that emits most of the light beam totally reflected by the total reflection surface. A transmissive screen characterized by having a lens surface as a component.