JPH0776826B2 - Lenticular screen and method of manufacturing the same - Google Patents

Description

The present invention relates to a lenticular screen used in a projection type video projector and the like, and a manufacturing method thereof.

<Prior Art> Generally, a transmissive projection screen used in a video projector or the like is required to have characteristics such as brightness of the entire screen, uniformity of brightness, and wide observation range. For this reason, diffusing the light incident in parallel on the observation side to emit the light is one of the means for widening the observable range.

As shown in FIG. 5, a screen of a conventional video projector uses a lenticular lens in which an arc-shaped convex portion (unit lens) 3 is provided only on a light-incident side surface 1A of a resin main body 1. . The light-exiting surface 1B of the lenticular lens 1 was formed as a flat surface.

When the acrylic resin is used, for example, the lenticular lens 1 is integrally manufactured by hot pressing a flat plate of acrylic resin having a concave portion formed on the mold surface.

<Problems to be Solved by the Invention> However, in such a conventional lenticular screen, since the diffusion angle of the incident light is small, the observable range is narrow, and the image peripheral portion (outer edge portion of the screen There is a problem that the brightness of) is lower than that of the central part.

Therefore, it is an object of the present invention to provide a lenticular screen having a novel structure in which the observable range is expanded and the brightness of the entire screen is uniform, and a method for manufacturing the lenticular screen.

<Means for Solving the Problems> A first invention of the present application has a plurality of cylindrical unit lenses each having a cross section formed in a curved projection shape with a predetermined curvature on a light-incident side surface of a main body, The focal position of the unit lens is a lenticular screen provided outside the light output side surface of the main body, and on the light output side surface of the main body, with a curvature larger than the curvature of the unit lens corresponding to the unit lens. It is a lenticular screen provided with a cylindrical lens portion having a curved and protruding cross section.

A second invention of the present application for manufacturing the lenticular screen according to the first invention comprises a step of integrally molding a plurality of cylindrical unit lenses, one surface of which is flat and the other surface is curved and projected with a predetermined curvature, and the flat surface. A step of bringing a photo-curable photosensitive resin layer of a predetermined thickness into close contact, and irradiating the photosensitive resin layer with parallel light rays that have passed through the unit lenses, thereby photo-curing a part of the photosensitive resin layer. And a step of developing the photosensitive resin layer, which is a method for manufacturing a lenticular screen.

<Operation> The lenticular screen according to the first invention of the present application,
Light entering from a plurality of cylindrical unit lenses tries to focus outside the light exit surface. At this time, since the cylindrical lens portion having a large curvature corresponding to the unit lens is arranged on the light output side surface, the focus position approaches the light output surface.
As a result, the emitted light has a larger diffusion angle than that in the case where the light emitting surface is flat.

In the method for manufacturing a lenticular screen according to the second invention of the present application, at the time of photo-curing, a part of the photosensitive resin layer disposed in close contact with the light-exiting surface of the main body is bonded to the main body as a cylindrical lens portion. It The laminating step can be omitted, and the adverse effect of the adhesive or the like can be avoided.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 3 show a lenticular screen according to a first embodiment of the present invention.

In FIG. 1, 11 is a screen main body made of acrylic resin or the like, and has a plate-like structure. This body 11
One end surface (lower surface in the figure) 11A is formed by a substantially flat surface, and the other end surface (upper surface in the figure) 11B is formed by a plurality of cylindrical unit lenses 13 ... There is. That is, the light-entering surface 11B with respect to the screen is composed of the cylindrical lenses 13 having a predetermined curvature. The focal length of the lens 13 is larger than the thickness of the main body 11, and the focal position is arranged outside the light output surface 11A.

The surface 11A on the light exit side of the main body 11 has the unit lenses 13 ...
Corresponding to, the convex lens portion 15 having a curvature whose curvature is larger than that of the unit lens 13 ... Is formed (the radius of curvature is such that the convex lens 13 on the light entering side is more than the convex lens 15 on the light exiting side. Is also big).

As a result, as shown in FIG. 1, the parallel light rays that have entered the main body 11 from the upper surface 11B are converged by the convex lens 13 ... And proceed so as to have a fixed position (the external space position of the light emitting surface 11A) as a focal point. To do. However, since the convex lens portions 15 ... Are arranged on the light exit surface 11A in the middle of the optical path, the light beam is refracted so as to be focused at a position closer to the light exit surface 11A. As a result, the angle of diffusion of the light beam becomes large, and the light beam is irradiated in a wide range.

FIG. 2 is a diagram showing the diffusion of light rays when a medium having a refractive index n and having a flat light output surface is tilted by an angle α. FIG. 3 is a graph showing the relationship between the inclination α of the plane and the diffusion angle φ when acrylic resin is used as the lenticular lens.

The refractive index n is expressed by the following equation, and the diffusion angle φ of the light emitting surface is expressed by the following equation.

n = sin θ2 / sin θ1 = sin (φ + α) / sin (θ1 + α) …… φ = sin ⁻¹ {nsin (θ1 + α)} − α …… In this case, when the material of the lenticular lens is acrylic resin Its refractive index is n = 1.48.

From the above, as shown in FIG. 3, the inclination angle α of the plane is
If is increased, the diffusion angle φ is also increased. Therefore, when the cross-sectional shape of the light emitting surface is a convex cross section having an arc, the inclination of the tangent to that surface becomes large, and the diffusion angle α can be made large. And the distance from the light entrance surface to the light exit surface in the main body, that is, the thickness of the screen main body 11 is slightly shorter than the focal length of the convex lens on the light entrance side, so the diffusion angle becomes large, and the observation The range that can be done is also expanding.

FIGS. 4 (A) to 4 (D) are cross-sectional views for explaining each step of the method of manufacturing a lenticular screen according to one embodiment of the present invention. Describing according to these figures, in FIG. 4 (A), first, a flat plate of acrylic resin is molded by hot pressing. In this case, the flat plate is the main body 11
And a cylindrical unit lens 13 formed by continuously forming a plurality of curved cross sections having a predetermined curvature on the light-incident side surface 11B.
・ ・ Moulded. Further, the focal length of each unit lens 13 ... Is longer than the thickness of the main body 11. In this case, the surface 11A on the light output side is formed as a flat surface.

Next, as shown in FIG. 3B, a photosensitive resin layer 21 which is photo-curable by ultraviolet rays is disposed in close contact with the flat surface 11A of the lenticular screen body 11 on the light exit side. That is, the photosensitive resin in a fluid state is poured into the inside of the frame body 23, and when it is solidified to a certain state, the flat surface of the screen main body 11 is brought into close contact with information. In this case, the photosensitive resin layer 21 has a predetermined thickness.

Next, as shown in FIG. 3C, a convex lens-shaped light entrance surface 11
Irradiate parallel rays of ultraviolet light from the B side in a direction orthogonal to the plane. As a result, a part of the photosensitive resin layer 21, that is, only the portion 25 where the convex lens 13 converges the light and concentrates it in the vicinity of the focal point and the light intensity is high, is photo-cured.

After that, by developing, the cylindrical lens portion 15 having an arcuate curved projecting cross section centered on the focal position of the unit lens 13 corresponds to the cylindrical unit lens 13 and the light emitting surface 11 of the main body.
It is formed in A. FIG. 4 (D) shows this state.

<Effect> As described above, according to the first invention of the present application,
Since the light emitted from the screen has a large diffusion angle, the observable range is widened and the brightness of the peripheral portion of the image is also increased.

Further, according to the second invention of the present application, since the optical positions of the lens on the light incident side and the lens on the light emitting side are matched, the manufacture thereof is extremely easy. Further, the manufacturing process is simple because a bonding step by forming a separate body is unnecessary. Furthermore, since no adhesive is used, the optical performance is stable.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an optical path of a lenticular screen according to a first embodiment of the first invention of the present application, FIG. 2 is a diagram for explaining an optical path of a general refractive index, and FIG. Similarly, a graph showing the relationship between the inclination of the plane and the diffusion angle, FIGS. 4 (A) to 4 (D) are sectional views for explaining each step of the manufacturing method according to the second invention of the present application, and FIG. It is a figure which shows the lenticular screen. 11 …… Screen body, 11A …… Exit surface, 11B …… Enter surface, 13 …… Unit lens, 15 …… Cylindrical lens part.

Claims (2)

[Claims] 1. A light-incident side surface of a main body has a plurality of cylindrical unit lenses each having a cross section formed in a curved and protruding shape with a predetermined curvature, and the focal point of the unit lenses is the light-exit side surface of the main body. A cylindrical lens having a cross-section of a curved projection with a curvature larger than the curvature of the unit lens, corresponding to the unit lens, on the light-exit side surface of the main body, the lenticular screen being provided outside In the lenticular screen provided with a portion, the cylindrical unit lens on the light incident side surface is formed by hot pressing an acrylic resin, and the cylindrical lens portion on the light exit side surface is formed of a photocurable photosensitive resin. A lenticular screen, which is formed by curing. 2. A step of integrally molding a plurality of cylindrical unit lenses in which one surface of an acrylic resin is curved and projected with a predetermined curvature by heat pressing, and a surface of a photo-curing type having a predetermined thickness on a surface facing the heat pressed surface. A step of bringing the photosensitive resin layer into close contact, a step of photo-curing a part of the photosensitive resin layer by irradiating the photosensitive resin layer with parallel rays that have passed through the unit lens, and the photosensitive resin layer And a step of developing the lenticular screen.