JP3036060B2 - Image display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device such as a liquid crystal projection television and a projector using a screen, and a screen.

[Prior Art] As shown in FIG. 3, a conventional image processing apparatus causes light from a light source 501 for projecting image information to be reflected by a screen 502 having a constant reflectance to reach an eye 504 of an observer. there were.

[Problems to be Solved by the Invention] However, in the related art, when there is disturbance light 503 such as sunlight or illumination light in FIG. 3, the entire screen 502 is constantly irradiated with the disturbance light 503, Is reflected by the screen 502 and reaches the observer's eyes 504 in a manner superimposed on the image information, thereby reducing the contrast of the image.

That is, as shown in FIG.
Since there is no change in time, the sum of the image information 601 and the reflected disturbance light 603 is the observed light amount 604. At this time, the contrast is determined by the ratio between the image signal component 605 and the disturbance component 606 indicated by oblique lines. This is because the disturbance component 606 also accumulates during the time when image information does not come due to the afterimage effect of human vision.

For this reason, it is difficult to observe in the daytime, it is necessary to darken the lighting in the room, and a light source with a very light output is necessary to make the image information sufficiently large against disturbance light. It was very difficult to observe.

Therefore, an object of the present invention is to obtain sufficient contrast even in the presence of disturbance light, even in the daytime or in an illuminated place,
It is an object of the present invention to provide an image display device capable of favorably observing an image.

[Means for Solving the Problems] An image display device according to the present invention includes: a reflection screen having a plurality of members; and an optical system for intermittently projecting light onto the plurality of members. Each of the plurality of members is rotatable, and each of the plurality of members is a first painted white.
And a second surface painted black, and when the light is projected onto the plurality of members, the first surface faces the optical system so as to reflect the light. When the light is not projected onto the plurality of members, the second surface faces the optical system, thereby achieving the above object.

[Operation] Many current image information display devices intermittently project image information.

For example, a movie has a structure in which image information is intermittently projected by a rotating shutter. In addition, liquid crystal projection televisions also intermittently project image information using scanning lines.

Alternatively, a laser scanner also displays a figure or the like by scanning with laser light.

Using such a light source, the reflectance of the screen is changed in synchronization with the intermittent period of the light source, and the image display device of the present invention is configured. As shown in FIG. 1, when the reflectance 102 of the screen is increased in synchronization with the image information 101, the reflected disturbance light becomes like 103. Therefore, the amount of light observed becomes 104, and the ratio between the image information component 105 and the disturbance component 106 shown by oblique lines is greatly improved.

The degree of improvement increases as the ratio of the high reflection time 108 to the period 107 decreases. Therefore, the effect increases as the unit of the area on the screen for changing the reflectance decreases.
Specifically, the effect is larger in the order of the screen unit, the scanning line unit, and the pixel unit.

Embodiment FIG. 2 shows an embodiment of the present invention. The light source is an overhead projector 401. A strobe light source 402 is used for the overhead projector 401. The screen 403 has a structure in which a plurality of elongated plates 404 each having a white front surface and a black back surface are arranged, and the plate 404 rotates in accordance with the flashing of the strobe light source 402. That is, the strobe light source 402
When is lit, the white side faces the front, and when it is off, the black side faces the front. The rotation cycle is 30 Hz.

In addition, if the present invention is applied to an image display device using a laser scan and the reflectance is changed in pixel units, a sufficient contrast can be obtained even with a low output laser such as a semiconductor laser.

[Effect of the Invention] Since the influence of disturbance light can be minimized in this way, a very high-contrast image comparable to a movie theater can be obtained even in the daytime or in an illuminated place. The practicality of the image display device can be greatly improved.

[Brief description of the drawings]

 FIG. 1 is a principle view of the present invention. FIG. 2 is an explanatory view of Embodiment 3 of the present invention. FIG. 3 is an explanatory view of a conventional technique. FIG. 4 is a diagram showing the principle of the prior art. 101 ... Image information 102 ... Screen reflectance 103 ... Reflection disturbance light quantity 104 ... Observation light quantity 105 ... Image information component 106 ... Disturbance component 403, 502 ... Screen 401 ... Overhead projector 402 ... Strobe light source 404 …… A plate with a white front and a black back 501 …… Light source 503 …… Disturbance light 504 …… Eyes of the observer

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) G09G 3/00 G09F 9/00 G03B 21/00 G02B 26/00 H04N 5/74

Claims (1)

(57) [Claims] 1. An image display device comprising: a reflection screen having a plurality of members; and an optical system for intermittently projecting light on the plurality of members, wherein each of the plurality of members is rotatable. Each of the plurality of members has a first surface painted white and a second surface painted black, and when the light is projected onto the plurality of members, An image display device, wherein a first surface faces the optical system so as to reflect the light, and the second surface faces the optical system when the light is not projected onto the plurality of members.