JPS61114232A - Manufacture of screen for video projector - Google Patents

Abstract

PURPOSE:To improve productivity and parting by injecting ultraviolet-ray setting resin between a flexible resin mold for a screen and an ultraviolet-ray transmissive plate, irradiating the ultraviolet-ray setting resin with ultraviolet rays through the ultraviolet-ray transmissive plate and setting the resin, and parting the mold. CONSTITUTION:While a vacuum is produced between a flexible resin mold 11 for a Fresnel lens which has a mold for lens surfaces and the ultraviolet-ray transmissive plate 6 through the evacuation of a vacuum pump through a discharge port 9, the ultraviolet-ray resin is injected through an injection port 8 and irradiated with ultraviolet rays by an ultraviolet-ray irradiating device 5 from above the plate 6 to set the ultraviolet-ray resin, molding the resin in the shape of the flexible resin mold 11 for the Fresnel lens. The plate 6 is parted after the molding. The flexible resin is preferably one kind between urethane resin and polymethyl pentene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a transmissive screen used in a video projector and the like, and particularly to an improvement in a method for manufacturing the screen.

[Conventional technology]

Figure 2(a) shows 7 as a general transmission screen.
FIG. 2(b) is a front view of the Lenelle/Z and a sectional view taken along the line n'b-nb in FIG. 2 (al).

In the figure, fi+ is a Fresnel lens, (2) is a lens surface, and (3) is a non-lens surface.

Such Fresnel lenses are manufactured by hot pressing thermoplastic acrylic resin, etc. Conventionally, these methods were manufactured by molding heated acrylic resin with a mold, cooling it, and then releasing the mold. .

However, in the above process, the acrylic resin shrinks by about 7 mm in the case of a circular Fresnel lens of 1111000 mm due to cooling after heating, so the non-lens surface (3) is heated to the full strength of the molding die. I tightened it up. In order to prevent distortion during LL cooling, slow cooling was necessary, and one process took more than 60 minutes.

As a result, it becomes very difficult to release the mold, and the time required for exclusive use of the mold is long, resulting in poor productivity.

For this reason, various manufacturing methods have been studied in order to obtain a Fresnel lens that does not use hot pressing and has the same performance as a Fresnel lens manufactured by a manufacturing method that uses hot pressing.

FIG. 3 is a sectional view showing a conventional Fresnel lens manufacturing method. In the figure, (4) is a mold for a Fresnel lens, (5) is an ultraviolet irradiation device, and (6) is an ultraviolet Ili! In the transparent plate, (7) is the injection direction of the ultraviolet curable resin, (8) is the injection port, (91 is the exhaust port, and (10j is the exhaust force direction).

A mold (4) with a lens surface mold and an ultraviolet transparent plate (6)
) is evacuated from the exhaust port (91) by a vacuum pump (not shown), and the injection port (8) is evacuated.
A UV curable resin is injected into the plate (6), and UV rays M are irradiated from the top of the plate (6) using an ultraviolet irradiation device +51 to cure the UV curable resin and mold it into the shape of the mold (4) of the Fresnel lens. . After molding, the VC @ marking plate (6) is removed and the mold is released.

[Problem that the invention seeks to solve]

In the conventional manufacturing method described above, the use of ultraviolet curable resin eliminates the need for heating and slow cooling during manufacturing, making it possible to complete one process in a short time. Like presses, the problem is that the molds are very expensive, and productivity is determined by the number of molds. Furthermore, there was also the problem that the mold releasability was affected by the glass transition temperature of the ultraviolet curable resin.

The present invention has been made to eliminate such problems, and is a video projector which has commercial productivity that is not limited by the mold base, and which has good mold releasability regardless of the glass transition temperature of the ultraviolet curable resin. The overall purpose is to obtain a method for manufacturing a screen for use in industrial applications.

[Means for solving problems]

The method of manufacturing a screen for a video projector according to the present invention includes injecting an ultraviolet curable resin between a flexible resin mold for a video projector screen having a lens surface mold and an ultraviolet transmitting plate. In this method, the above-mentioned ultraviolet-curable resin is irradiated with ultraviolet light through a sex plate, cured, and then released from the mold.

[Effect]

The use of the flexible resin mold for the screen of a video projector in this invention eliminates the need to make many molds with high VC sieve value as in the past, and makes it possible to use inexpensive flexible resin from one mother mold. By transferring a large amount of the entire mold and using it for manufacturing screens, it was possible to significantly improve productivity, and by conveniently using inexpensive flexible resin molds, product costs were significantly reduced. . Furthermore, by changing the mold from metal to flexible material, ultraviolet #I, which has mold releasability,
Not only does this eliminate the dependence on the glass transition temperature of the curable resin, but the mold releasability is improved more than ever.

〔Example〕

FIG. 1 is a sectional view showing a method for manufacturing a Fresnel lens according to an example of the present invention, and in the figure, (4) to
(10) is the same as in FIG. 2, and %01) is a flexible resin mold for Fresnel lenses.

RTV rubber comparand (manufactured by Shin-Etsu Silicone, product name: Kl1)-1 as a flexible resin mold 0υ for Fresnel lenses
300 RTV, same < xz-1o, a RTV)
A friend who uses k.

Note that the method of transferring the flexible resin mold from the mold is not the purpose of this invention, and therefore the description thereof will be omitted.

First, the exhaust port (9) is inserted between the Fresnel lens flexible resin mold (o1) having the lens surface mold and the ultraviolet transmitting plate (6).
While creating a vacuum by evacuation using a vacuum pump (not shown), inject external radiation hardening oil from the injection port (8). Inject the ultraviolet irradiation device (5) from the top of the plate (6).
) to cure the ultraviolet curable resin and mold it into the shape of the readable resin mold (II) for Fresnel lenses. The plate (6) is completely removed using a molding iron and released from the mold.

The Fresnel lens obtained in this way satisfies the same characteristics when using a conventional mold.

In the above embodiments, RTV rubber compound was used as the resin used for the flexible resin mold.

Rubber M such as product name: Melkit C), urethane resin (e.g., manufactured by Nippon Zeon, product name: Boliol 3028B System 96M), polymethylpentene resin (e.g., Mitsui Petrochemical Shrimp, product name: TPX), etc. It's okay,
Experiments were focused on obtaining high-quality readable resin molds.

Furthermore, in the above embodiment, Fresnel lens is used as a method for manufacturing a screen for a video projector. As described in the case of manufacturing, a lenticular lens can be obtained by using a mold whose lens surface is a lenticular lens surface, and furthermore, by molding a mold with an appropriate lens surface on the surface facing the lens surface of the ultraviolet-transparent plate, A screen having a Fresnel lens surface and a lenticular lens surface on both sides can be obtained in the same manner as in the above embodiment.

As a method for injecting the ultraviolet curable resin in one embodiment of the present invention, we have described a method in which the resin is injected while evacuation is performed. good.

〔Effect of the invention〕

This development (7) is as explained above, by injecting an ultraviolet curable resin between the flexible resin mold for the screen of a video projector having a lens surface mold and the ultraviolet ray transparent plate. By irradiating the above-mentioned ultraviolet curable resin with ultraviolet rays to cure it and releasing it from the mold, it is possible to obtain a complete manufacturing method for a screen for a video projector with high productivity and good mold releasability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a method for manufacturing a Fresnel lens according to an embodiment of the present invention, FIG. 2 (at is a front view of a general Fresnel lens, and FIG. 2(b) is a ), FIG. 3 is a sectional view showing a conventional Fresnel lens manufacturing method. In the figure, (5) is an ultraviolet irradiation device, (6) is an ultraviolet transmitting plate, ( )) is the injection direction of UV-curable 11 fat, α
υ is a flexible resin mold for Fresnel lenses. In each figure, the symbol -1 indicates the same or corresponding part.

Claims (6)

[Claims] (1) An ultraviolet curable resin is injected between a flexible resin mold for a video projector screen having a lens surface mold and an ultraviolet curable plate, and the ultraviolet rays are irradiated to the ultraviolet curable resin through the ultraviolet ray transparent plate. A method for manufacturing a screen for a video projector, which is then released from the mold. (2) The method for manufacturing a screen for a video projector according to claim 1, wherein the flexible resin is one of rubbers, urethane resins, and polymethylpentene resins. (3) The method for manufacturing a screen for a video projector according to claim 1, wherein the lens surface is a Fresnel lens surface. (4) The method for manufacturing a screen for a video projector according to claim 1, wherein the lens surface is a lenticular lens surface. (5) The method for manufacturing a screen for a video projector according to claim 3, wherein the surface of the ultraviolet-transparent plate facing the lens surface is in the form of a lenticular lens surface. (6) The method for manufacturing a screen for a video projector according to claim 4, wherein the surface of the ultraviolet-transparent plate facing the lens surface is in the form of a Fresnel lens surface.