JPS58143682A - Translucent screen device - Google Patents

Abstract

PURPOSE:To improve horizontal and vertical directivities in any position, by forming a translucent screen with a lenticular lens and a Fresnel lens. CONSTITUTION:A projection screen plate 19 is provided with a lenticular lens 20 and a Fresnel lens 21. The center of the Fresnel lens 21 is shifted upward or downward from the screen plate 19 and is attached to the center of the geometric center of a screen surface. As the effect of the Fresnel lens 21 which has the center shifted, the position where the whole of the surface of the screen 19 is seen with a uniform luminance is spread in a part lower than the normal to the screen 19. That is, when an observer sees the screen in the sedentary or recumbent posture, the can obtain the most suitable position. If the sees the screen in the standing posture mostly, the screen 19 is attached upside down.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a directional transmissive screen device used in projection televisions, etc., in which the optimum viewing position is approximately in front of the projection screen surface. This is an attempt to solve the problem that due to the limited number of screens, for example, when viewing while standing or lying down, the user deviates from the optimal viewing position and cannot see the best screen.

FIG. 1 shows the structure of a transmissive screen commonly used in conventional projection television apparatuses. k (ILI in the figure) is a structure in which a lenticular lens surface 2 and a Fresnel lens surface 3 are applied to one screen plate 1, respectively.

(With plate 5 processed from blld lenticular lens 4.

This is a transmission type screen constructed by combining plates 7 formed by processing Fresnel lenses 6.

Although there are some differences in structure in (fLl and (bl) in Figure 1, they are essentially the same.Also, in actual screens, a diffusing agent is mixed into the screen material to obtain light diffusion. , or use a diffusion process on the surface of a lenticular plate.0 The effects of configuring a screen with this structure are as follows: First, by using vertical lenticular lenses 2.4. The light from the projection device is diffused over a very wide area in the horizontal direction, and is only slightly diffused in the vertical direction.Fi is approximately ±30 in the horizontal direction and approximately ±10 in the vertical direction in the one that is in practical use. ' It has a diffusion characteristic of '.

The reason why the horizontal diffusion characteristics are increased and the vertical diffusion characteristics are not increased so much is that, as shown in FIG. 2, the viewer 10 viewing the screen 9 of the projection television 8 is almost horizontal This is because the possibility of distribution in the vertical direction is low. In Figure 2, (2L)U is a view seen from the lateral direction, 11 is the normal line from the center of the screen 9, 12 is the range of directivity in the vertical direction, (bl
is a diagram seen from the vertical direction, and 13 indicates the range of horizontal directivity.

As can be seen from FIG. 2, it is very effective to use a lenticular lens structure as the screen 9.

Next, FIG. 3 is a diagram for explaining the action of the Fresnel lens 3.6. ILIVi Fresnel lens 3 in Figure 3
．． 6 is a diagram showing a case in which 6 is not used.

14 is a projection device, 16 is a screen (having only a lenticular lens surface), 16 is the directional characteristic of the Fi screen 16, 17 is the position of the person looking at the screen surface,
(b) shows the brightness distribution on the surface of the screen 16 viewed from the position 17. As you can see from the diagram, K, projection screen 1
The brightness at the center of the screen 16 is very high, but at the edges of the screen 16, the angle of the light rays entering the screen 16 from the projection device 14 becomes very large.
Since the peak of directivity points in the direction of the incident light beam, the brightness seen from position 17 is very low.

On the other hand, if the Fresnel lens 18 is arranged as shown in FIG. In that case, position 1
The brightness distribution on the surface of the screen 160 viewed from 7 is as shown in (bl), and almost uniform brightness can be obtained over the entire surface of the screen 16.

As mentioned above, if a screen device is used that is processed with lenticular lenses and ethofresnel lenses, it is possible to construct a very effective screen.

However, on the other hand, when this screen surface is used, as shown in Figure 2, there is no problem when looking at screen 9, but in reality, the viewer 1o is on the floor. Sit down and watch! Sometimes I just lie down and watch. In addition, there may be cases where the image is viewed while standing.

In that case, the position of the eyes will deviate from the directivity range 11 shown in FIG. 2, making it impossible to view the screen 9 while the original performance of the screen 9 is being exhibited. In particular, when a projection television is used in a general household, there are many opportunities to watch it while sitting on a tatami mat or lying down, just like when watching a conventional direct-view television, and the vertical Directivity becomes a problem.

SUMMARY OF THE INVENTION The present invention aims to provide a projection screen that overcomes these drawbacks, and will be described below with reference to embodiments.

In this screen device, Fi, as shown in FIG.
The lenticular lens 20 and Fresnel lens 21 are provided on the projection screen plate 19, so that the center position of the Fresnel lens 21 is in the vertical direction of the screen plate 19, that is, in the short side direction, with respect to the geometric center of the screen surface. It is characterized by being made to shift.

This also applies to structures in which the lenticular lens plate and the Fresnel lens plate are configured separately.

FIG. 6 shows the vertical directivity characteristics when using a screen having such a structure. There is no change in the horizontal directivity characteristics compared to the conventional model. As is clear from the figure, if a Fresnel lens 2° with its center shifted is used, the screen 1
The viewing position 23 where the entire surface of 9 has uniform brightness is located below the normal line 22 of the screen, making it possible to obtain the optimum directivity when viewing while sitting or lying down. .

In addition, when viewing in a place where there are many opportunities to stand and view, by attaching this screen 19 upside down, it is possible to set the optimum directivity above the normal line 22 of the screen 19, so that the screen surface can be seen in the best condition. You can see it.

An example of a structure for reversing the vertical direction of the screen 19 is as shown in FIG. 7, for example.

A long hole 2o for inserting and removing the screen 19 is provided in the side surface of the casing 24 of the projection television, and the screen 19 is pulled out from there, and the screen 19 is placed upside down again.
This can be achieved by making it possible to insert . Or, attach screen 1 to the mounting frame of screen 19.
9 can be attached to the casing 24 from the front, it can also be realized by having a structure that allows reverse coverage for each screen frame.

As described above, according to the present invention, by shifting the center of the Fresnel lens, it is possible to obtain a projection screen IJ that can have the optimum directional characteristics depending on the viewing position, and to improve projection television. It is possible to change the appropriate viewing position.

[Brief explanation of the drawing]

FIG. 1 (!Ll, [bl is a side view, plan view, and characteristic diagram of a conventional projection screen device (bl is a side view, plan view, and characteristic diagram for explaining its usage state, and FIG. 6 is a transmission screen in an embodiment of the present invention) A perspective view of the device, FIG. 6 is a side view illustrating the state of use, and FIG. 7 is a perspective view when used in a projection television. 19...Screen board, 20.・Lenticular lens, 21... Fresnel lens. Name of agent: Patent attorney Toshi Nakao, male, 1st person
Figure ((1) 3 / Figure 2 Figure 3 Figure 5 Q Figure 6 q

Claims (1)

[Claims] A lenticular lens is provided on one surface and a Fresnel lens is provided on the other surface, or a screen with a lenticular lens and a Fresnel lens are combined to form a transmissive screen. A transmission type screen device characterized in that the center of the screen is shifted from the geometric center of the screen surface in the direction of the short side of the screen surface.