JPS58192023A - Lenticular lens sheet - Google Patents

Abstract

PURPOSE:To obtain a video which is uniform in luminance, well-balanced in its color and easily visible, by forming the reverse side of a lens to a prism of a convex or concave polygon in accordance with the surface, dispersing fine particles in the inside, and making a light nontransmission part of the reverse side light-absorbable. CONSTITUTION:A lenticular lens 11 is provided on the incident part of light of a lens sheet 1, a trapezoidal prism 12 opposed to said lens is formed on the reverse side, 0.5-5wt% fine particles for dispersing the light, such as glass powder, etc. are dispersed in the inside, and black ink is printed to a black stripe 2, which is made light-absorbable. Since the prism 12 is provided, a radius of curvature of a lens can be selected over a wide range, and a lens which is well- balanced in its color is designed. Also, since the fine particles exist, there is no difference of luminance in a position where an observer sees, and external light is absorbed by the stripe 2. Therefore, it is possible to obtain a video which is well-balanced in its color, uniform in luminance and easily visible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in lenticular lens sheets, particularly lenticular lens sheets that are used in combination with Fresnel lens sheets to form transmission projection screens.

Various types of transmissive screens have been devised, but some, such as projection televisions,
When the colors are separated into green and blue and combined on a screen, a combination of a Fresnel lens sheet and a lenticular lens sheet is generally used.The Fresnel lens has the function of concentrating the optical axis on the viewer. However, lenticular lenses not only provide images with less color unevenness, but also have anisotropy, meaning that light spreads over a wide predetermined angular range in the horizontal direction, but not so much in the vertical direction.
play the role of ensuring that

The desired characteristics of this type of transmissive screen are: first, within a predetermined range in the horizontal direction along the screen surface;
The brightness of the light on the screen, in other words, the amount of light that passes through the screen, should be as uniform as possible. Furthermore, in general, the positions of the red, green, and blue light sources are not the same, so in order to correct the deviation and perform color synthesis, it is necessary to design the lens accordingly.
Furthermore, in order to reduce the influence of external light and make the screened image easier to see, the structure should absorb as much external light as possible and reflect it.

An object of the present invention is to provide a lenticular lens sheet constituting a transmission screen that meets these demands.

The reunticular lens sheet of the present invention constitutes a transmission type projection screen in combination with a Fresnel lens sheet, and the back surface is formed into a convex or open rectangular prism corresponding to the front surface to allow light to enter the lens. It is characterized by having scattering fine particles dispersed therein and by making the light-impermeable part on the back surface light-absorbing.

As the light-scattering fine particles dispersed inside the lens, fine particles of a substance having a refractive index different from that of the lens material are used. Specific examples include glass powder, finely divided silica, extender pigments such as alumina, or resin powders, with a particle size of about 05 to 30 μm. The appropriate blending ratio for the lens material is in the range of 0.5 to 5% by weight.

Uniform dispersion in the lens sheet can be achieved, for example, by melt-kneading with a lens material, usually a plastic such as polymethyl methacrylate, extruding and roll-forming or press-molding into lenses.

It is known that the non-light-transmissive portion of a lenticular lens sheet is made light-absorbing to reduce the influence of external light.
This has already been done under the names of ``blanks drive'' lenticular, etc. Therefore, this can be done using existing technology, for example, by molding the lens so that the part that will be the black stripe protrudes, and then rolling it into place. Printing matte black ink by coating,
So .

On the contrary, a method can be adopted in which the black stripe part is recessed and molded, and the ink is left only in the recessed part using the doctor coat method.

Examples of the lenticular lens sheet of the present invention will be explained with reference to the drawings.

In the example shown in Fig. 1, the surface of a lens sheet 1 having dispersed light-scattering fine particles inside, that is, the light incident part (') has a lenticular lens 11, and the back surface, that is, the light emitting part is A trapezoidal prism] 2 is formed, and a blank drive 2 is provided in the light-opaque part between each prism to absorb external light.・The light from the light source is
Front: ζO(・Ta) Light is focused by a Fresnel lens (not shown), enters and exits as shown by the arrow.

The example shown in FIG. 2 is different in that the black stripe 2 is provided in a protruding manner in FIG. 1, whereas it is provided in four parts here, but the other points are the same.

On the other hand, in the example shown in FIG. 3, the prism 12 in FIGS. 1 and 2 has a convex shape, but is formed in a concave trapezoid shape.

In the lenticular lens sheet of the present invention, a lenticular lens is provided at the light entrance part, a prism is formed at the light exit part, and the shape of the prism is appropriately selected according to the arrangement of the light source (by which the radius of curvature of the lens can be broadly observed and In addition to being able to choose from a wide range of colors, it is also easy to design lenses that balance the colors of red, green, and blue.

The fine particles dispersed inside the lens are effective in appropriately scattering light, reducing differences in the amount of light transmitted through the screen depending on location, and making it uniform. Therefore, subtle differences in brightness that are felt due to differences in the position of the person viewing the screen or the viewing angle become less of a problem.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are all enlarged sectional views showing the structure and operation of an example of the lenticular lens sheet of the present invention. ■ Lenticular lens sheet 11... Lenticular lens 12... Prism 2/Blank stripe

Claims (2)

[Claims] (1) A lenticular lens sheet that is used in combination with a Fresnel lens sheet to form a transmission projection screen, the back surface of which is formed into a convex or rectangular prism corresponding to the front surface, and the inside of the lens is filled with fine particles that scatter light. A lenticular lens sheet comprising: a lenticular lens sheet having a lenticular lens dispersed therein, and a lenticular lens sheet having a non-light transmitting portion on the back surface having a light absorbing property. (2) The lenticular lens sheet according to claim 1, wherein the prism is convex or convoluted.