JPS59133535A - Translucent screen - Google Patents

Abstract

PURPOSE:To broaden observation angle ranges in the horizontal and vertical directions by constituting a fly's eye lens provided on one face of the screen of a fly's eye lens containing a crest part and a trough part, and forming a total reflecting plane between the two. CONSTITUTION:One face of the transmission type screen B is made of a circular Fresnel lens and a fly's eye lens 5 is provided on nearly whole of opposite face. The fly's eye lens 5 is divided into crest part fly's eye lens 8 of convex crest part having 9 rise-up part 6 and a trough part fly's eye lens 10, and a total reflecting plane is formed on the rise-up part 6. Projected light incident on the Fresnel lens 4 side is refracted by the lens 4 and radiated. However, a part of the light is totally reflected by the total reflecting plane 11 and radiated from the lens 8. Thus, as lenses are provided at crest part and trough part, it has diffusion characteristic in horizontal direction and vertical direction, and the extent of observable angle can be broadened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a wide observable angular range even when projecting light with relatively poor light intensity, such as from a glow projector type television, and can regulate the brightness distribution in that angular range. Relating to an improved transmissive screen.

As shown in Figure 1, the peaks l of the lenticular are connected to each other via the valleys, and after the light beam incident on the valleys of the medium is totally reflected, it passes through the top surface of the peaks and exits. A lenticular lens A for screens in which a total reflection surface 3 is formed in one part is already known (Japanese Unexamined Patent Application Publication No. 130/1986). According to the above-mentioned conventional technology, the brightness of the projected light beam within the projection angle can be made uniform, and a relatively wide projection angle can be obtained. It can be used as a screen.

However, the above-mentioned conventional lenticular lenses for screens also have drawbacks.

The above-mentioned conventional lenticular lens for screens has a lenticular lens l on the observation side, so if the lenticular lens is formed vertically as shown in Figure 1, the projection light source spreads out in the horizontal direction, creating a dazzling image. In addition, due to the action of the lenticular lens, the emitted light is diffused only in the horizontal direction in the above example, but not in the vertical direction, so vertical observation is possible. It has disadvantages such as narrow range.

In addition, in the conventional screen lens described above, the lenticular lens on the observation side reflects external light such as indoor lighting in a vertical line, which impairs the contrast of the image.

The present invention solves the above-mentioned drawbacks of the conventional lenticular lenses for screens, and the transmissive screen of the present invention has one surface made of a circular Fresnel lens and the other surface made of a fly's eye lens. , and the fly's eye lens includes a peak fly's eye lens provided at the peak of a convex portion having a rising portion, and a trough fly's eye lens provided in a valley between the convex portions. Further, each of the rising portions is characterized in that a portion thereof is a total reflection surface that tapers upward as it approaches the top of the convex portion. Note that the fly's eye lens herein refers to a lens in which a large number of isotropic or anisotropic lenses are arranged in series.

Hereinafter, the present invention will be explained in detail using the drawings.

Figure 1 shows an embodiment of the transmission screen of the present invention,
One surface of the transmission screen B (corresponding to the back surface in Figure 1) consists of a circular Fresnel lens, and the projection light incident on the circular Fresnel lens is reflected by the circular Fresnel lens. It is refracted depending on the shape and the refractive index of the lens material, and is usually located on the other side of the transmission screen (corresponding to the front surface in Figure 1), at a distance of 3 to 10 m from the position of the transmission screen. Like normally concentrating light? -Design and manufacture a cular Fresnel lens.

Next, on the surface of the transparent screen B opposite to the surface having the circular Fresnel lens (the front surface in Figure 1), a fly's eye lens 3 is provided over the entire surface. The fly's eye lens j is a convex part 7 having a raised part 6, and a trough part between the top part of the convex part 7 and a valley part between the convex parts. It is broadly classified into fly's eye lens lθ.

Each rising portion 6 is provided for the purpose of totally reflecting the incident light from the circular Fresnel lens l side and emitting the totally reflected light from the lens at the top of the mountain. It has a total reflection surface l/.

Next, in order to explain the shape and function of the above-mentioned transmission screen in more detail, a horizontal sectional view of the transmission screen shown in FIG. 1 is shown as FIG. 3.

In addition, in FIG. 3, both the mountaintop-worker's-eye lens t and the valley's fly-eye lens IO are drawn as passing through the most protruding part.

As shown in Figure 3, the rising part consists of the total reflection surface // of the part near the center of the fly's eye lens in the trough, and the part l:1 parallel to the optical axis of the fly's eye lens. . Considering the molding of a transmission type screen, the latter part l has the advantage of being designed to be slightly tapered upward as shown in Fig. 3, making it easier to release the mold after molding. ~3
It is preferable to have an angle of approximately 0, but it is preferable to have an angle closer to Oo from the point of view of effective use of incident light.

Next, the total reflection surface of the part near the rising part O, the valley of the fly's eye lens iov // is the part of the fly's eye lens g, 1!1h
) - If the angle α of the planes is perpendicular (where n is the refractive index of the material of the transmission screen), then the light totally reflected by the total reflection surface II, for example a and b in Fig. 3, is All of the light indicated by can be emitted from the fly's eye lens at the top of the mountain as a' and b.

n is i'192 for acrylic resin, which is a typical material, and in this case α≧ttqt°.

Note that the light that enters the transmission screen, is refracted, and heads toward the fly's eye lens g at the top of the mountain, for example, c in Fig. 3,
At the time of exit, the beams d and e are diffused within the range of angle β according to the shape of the fly's eye lens at the top and the refractive index of the material of the transmission screen.

The total reflection surface // in Figure 3 is involved only in total reflection inside the transmissive screen, and therefore no light is emitted from the total reflection surface //, so this part is shielded with a light absorption layer (not shown). It is possible to improve the contrast of the image. In addition, in order to prevent part of the light beam from being absorbed by the light absorption layer during total reflection, a material with a refractive index smaller than that of the material of the transmission screen is placed between the total reflection surface l/ and the light absorption layer. A layer (not shown) may be interposed.

The valley fly's eye lens indicated by IO in FIG.
It emits with.

The angle r is the point at which the emitted light f and g are at the shoulder 1 of the fly's eye lens at the top of the mountain.
5, ■ the horizontal pitch P of the fly's eye lens g at the top of the mountain, ■ the horizontal pitch P of the fly's eye wrench 10 at the valley, and ■ the fly's eye lens g at the top. Eye lens shoulder lj ~ Tanibe fly eye lens IO
3 or more of the vertical distance between the end boundary 13 of the total reflection surface l/
It can be determined from two values.

In the above, the values of P, , P, , h are - for example, P/
is 0.2~jw, P2 is 0.2~. 7 Ill, h
is 0. / ~U3■.

In addition, in the above, the values of P/ and P, the diffusion angle β and r can be arbitrarily determined except for the above-mentioned confectionery regarding γ, but the mountaintop fly's eye lens t has a relatively wide diffusion angle. The trough fly's eye lens io is suitable for obtaining a relatively narrow diffusion angle, so it may be determined as appropriate depending on the application. Similarly, light emitted from the fly's eye lens g at the top of the mountain after being reflected by a total reflection surface (for example, a
And b) and the light directly emitted from the fly's eye lens g at the top of the mountain without touching the total reflection surface (for example, C1d and e), the former light is more diffused than the optical axis of the fly's eye lens g within the diffusion range. The latter light also contributes to diffusion in a distant range, and the latter contributes to diffusion in a range closer to the optical axis, so the height of the total reflection surface and the pinch of the fly's eye lens at the top of the mountain P1. The distribution of the emitted light can also be changed by adjusting the focal length of the fly's eye lens at the top of the mountain.

In the above description, the horizontal cross-sectional shape and function of the transmission screen according to an embodiment of the present invention have been shown. Next, referring to FIG. I will explain about it.

As shown in FIG. 3, incident light beams 1 and j are refracted at the valley fly-eye lens 10 and exit at a diffusion angle of θ/. Further, as shown in Fig. S, the incident lights k and I are refracted at the fly's eye lens at the top of the mountain and exit at a diffusion angle of θ. Pitch Q of the top fly's eye lens in the vertical direction
The pinch Φ of the fly-eye lens in the trough area and the focal length of the fly-eye lens in the peak area and the focal length of the fly-eye lens in the trough area can be set arbitrarily, but usually the vertical diffusion angle is S0~ It may be set to about 200.

In addition, in the above explanation, each fly's eye lens is illustrated as an anisotropic convex lens, and the shape is assumed, but the shape of each fly's eye lens is not limited to this. , an anisotropic or isotropic convex or concave lens having a cross-sectional shape of a quadratic curve such as a circle, an ellipse, or a parabola, or these lenses may be combined as appropriate. When manufacturing molds using such a fly-eye lens-shaped rotary cutting blade, the rotary cutting blade is sent parallel to the mold surface while moving forward and backward in the thickness direction of the mold in a predetermined manner. After obtaining a mold, it can be manufactured by shaping a transparent plastic plate using the obtained mold.

In the above embodiments, the convex portion is in the form of a convex strip, but the convex portion is not limited to the convex strip shape.
As shown in the figure, each may be an independent convex portion/6.

As shown in FIG. 6, the horizontal cross-sectional shape and function of the transmission screen in which the convex portions/A are independent are the same as those explained using FIG. 3 for the first embodiment. The same applies to the vertical cross-sectional shape and function of the transmission screen shown in FIG. 6, as well as the matters explained using FIG. 3. However, as mentioned above, usually
The vertical diffusion angle of the transmission screen is 3°~koθ0
Since the degree is sufficient, we omit the total reflection surface 1, which is shown as a horizontal plane in the figure, and the total reflection surface 7g, which is shaded in Figure 6. The other side is the part perpendicular to the optical axis, i.e. parallel to the optical axis (for example /?
) may be extended as it is until it comes into contact with the valley fly's eye lens.If a total reflection surface is not provided in this way, the light absorption layer is made of a material with a refractive index smaller than that of the material of the transmission screen. It may be provided directly on the rising portion without intervening layers.

Furthermore, when the convex portions 16 are independent as described above, of the t side surfaces of the convex portions 16, the portions corresponding to the upper and lower surfaces in FIG. 6 are cylindrical side surfaces, and the mold It is convenient to use a rotating cutting blade during manufacturing.

Compared to the conventional lenticular lenses for screens described above, the above-mentioned transmission screen of the present invention has fly's-eye lenses in both the crests and the troughs, so it can only be used in one direction, for example, horizontally. It not only has diffusion characteristics in the vertical direction, but also in the vertical direction, so it has a wide observable range in the vertical direction, and it has a fly's eye lens instead of a lenticular lens. Therefore, even if external light is reflected, it appears as dots instead of lines, so there is very little damage to the image.

[Brief explanation of the drawing]

1. FIG. 1 is a perspective view of a conventional lenticular lens for screens, FIG. 1 is a perspective view of a transmission screen according to an embodiment of the present invention, and FIG. 3 is a horizontal sectional view of the transmission screen of FIG. 2. 4 and S are both vertical sectional views of the transmission screen shown in FIG. FIG. 4 is a vertical sectional view through the most protruding point of the top fly's eye lens, and FIG. 4 is a perspective view of a transparent screen according to another embodiment of the present invention. No. 0 No. 1 Circular Fresnel lens 7
・・・・・・・・・Convex part G-・Ku・No. 0・・・Mountain top fly’s eye stain・・・・・・・・Valley part 10・・・・・・・・・－・Tanibe fly's eye lens 6・・・・・・・・・Rising part// ・
・・・・・・・・・Total reflection Painting ability 1 Figure 4 Figure 5 Figure 199- Fang 6

Claims (5)

[Claims] (1) One surface is made of a circular Fresnel lens, and the other surface is made of a fly's eye lens, and the fly's eye lens has a convex portion having a raised portion with a fly's eye lens and a top portion of the convex portion. , consists of a trough fly's eye lens provided in the trough between the convex parts, and furthermore, a part of each raised part increases as it approaches the top of the convex part. A transmissive screen characterized by a converging totally reflective surface. (2) Top part The transmission screen according to claim 1, wherein the fly's eye lens is provided at the top of the convex part of the convex strip. (3) The transmission screen according to claim 1, wherein the fly's-eye lens is provided at the top of each independent convex portion and has a temperature of 0.degree. (4) The transmission type according to any one of claims 1 to 3, wherein the total reflection surface has an angle α with a surface perpendicular to the optical axis of the lens. screen. (5) The total reflection surface also has a refractive index of transmission type IJ −
The transmission screen according to any one of claims 1 to q, characterized in that it has a layer made of a material whose refractive index is smaller than that of the material of the screen, and a light absorbing layer on the layer.