JP2743939B2 - Polarizing screen device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing screen device and, more particularly, to a reflective or transmissive polarizing screen device used for displaying an image projected from a liquid crystal projector.

[0002]

2. Description of the Related Art In recent years, in conferences or lectures, the number of presentations while projecting images or natural images by a personal computer on a large screen has increased. When projecting such an image on a large screen, a CRT projector or a liquid crystal projector is used. On the other hand, devices such as an OHP (overhead projector) or a slide have been used for the above-mentioned applications. Among the above-mentioned apparatuses, the liquid crystal projector is very suitable for displaying an image by a computer because one pixel can clearly display one pixel.

Generally, in a liquid crystal projector, the brightness of a pixel is controlled by adjusting the amount of light transmitted through a liquid crystal panel. However, when the light is transmitted, the liquid crystal emits only light having a polarization angle in a predetermined direction. Has the characteristic of transmitting light. Therefore, generally, the light projected from the liquid crystal projector has the same polarization direction. A so-called polarizing screen device makes it possible to view a clear image even in a bright place by utilizing this property.

Here, a conventional polarizing screen device will be outlined with reference to FIG. The polarizing screen device includes a polarizing screen including a polarizing sheet 403 and a reflecting sheet 404. In the case of a reflective polarizing screen, the polarizing sheet 403 is attached to the surface of the reflecting sheet 404. The polarizing sheet 403 and the reflection sheet 404 are held by a screen holding frame 405 as shown in FIG.
Are supported by the screen table 402.

[0005] In such a polarizing screen device, the polarizing sheet 403 transmits only light having the same polarization direction as that of the light projected from the liquid crystal projector. That is, the polarizing sheet 403 has the same polarization direction as the polarization direction of the projection light from the liquid crystal projector. Therefore, all light projected from the liquid crystal projector can pass through the polarizing sheet, but only light having the same polarization direction as the polarizing sheet, such as room light, is transmitted. As a result, the reflection of room light by the polarizing screen (that is, the reflection sheet 404) becomes approximately half of the room light incident on the polarizing screen. As described above, when the polarizing screen is used, the projection light from the liquid crystal projector can be clearly seen even in a bright room.

[0006]

When actually giving a lecture using a liquid crystal projector, OHP may be used in combination or two liquid crystal projectors may be used. In such a case, two screens are prepared, or two devices are switched and controlled, and an image from only one is projected onto one screen.

[0007] However, when the screen is placed in a narrow space,
In general, it is difficult to set up a table, and when switching is performed as described above, there is a problem that two images cannot be viewed simultaneously.

In addition, if two images are forcibly projected on one screen, there is a problem that mutual interference occurs at a portion where the projection light overlaps, and the images are extremely difficult to see.

An object of the present invention is to provide a liquid crystal projector and an OH
An object of the present invention is to provide a polarizing screen device that can prevent projection light from interfering with each other when P is used together or when two liquid crystal projectors are used simultaneously.

[0010]

According to the present invention, there is provided a polarizing screen device used for displaying a projected image, comprising: a polarizing screen in which a plurality of regions having different polarization directions are defined as a polarizing region; And a moving means for moving the positions on the projection surface for the plurality of polarizing regions.

Further, according to the present invention, there is provided a polarizing screen device used for displaying a projected image, comprising: a polarizing screen in which a plurality of regions having different polarization directions are defined as polarizing regions; And a changing means for changing an area occupied on the projection surface.

Further, according to the present invention, a polarizing screen having a predetermined polarization direction, which is used together with two projectors whose polarization directions are different from each other by 90 degrees, and the polarizing screen perpendicular to the polarization screen surface is provided. And a rotating means for selectively displaying the projected images simultaneously projected from the two projectors on the polarizing screen by rotating them around the axis, thereby obtaining a polarizing screen device.

In addition, according to the present invention, there is provided a polarizing screen device used for displaying a projected image, wherein the polarizing screen has a plurality of polarizing screen portions extending in a predetermined direction, and the polarizing screen portions are independent of each other. Rotating means for rotating about an axis extending in the predetermined direction.
The polarizing screen unit has first and second main surfaces, and the first and second main surfaces have polarization directions different from each other, thereby obtaining a polarizing screen device.

[0014]

According to the present invention, the polarization direction of a partial region of a polarizing screen can be made different from that of another region. For example, when two projection lights having different polarization directions are projected on the screen, one region on the screen is projected. The partial region reflects only the projection light in the vertical polarization direction (in the case of the reflection type), and the other regions reflect only the projection light in the horizontal polarization direction.
Therefore, only the projection lights whose polarization directions match each other are reflected, and the projection lights do not interfere with each other.

Further, if the polarization direction of the entire polarizing screen is changed, when two projection lights having different polarization directions are projected on the screen, the projection light coincident with the polarization direction of the polarization screen is selectively reflected. Will be.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

First, referring to FIG. 1, the illustrated example is a so-called winding type polarizing screen device. This polarizing screen includes polarizing sheets 101 and 102 and a reflecting sheet 103 made of aluminum foil. The polarizing sheets 101 and 102 and the reflective sheet 103 form a polarizing screen. The polarizing sheets 101 and 102 are adhered to the surface of the reflecting sheet 103 with different arrangement from each other. That is, the polarizing sheets 101 and 102
Are different in the bonding position on the reflection sheet 103. For example, the polarizing sheet 101 transmits polarized light in a direction perpendicular to the plane of FIG.
To transmit polarized light in the horizontal direction with respect to the paper surface of FIG.

The take-up rolls 104 and 105 are used when the above-described screen is taken up. By rotating these take-up rolls 104 and 105, the entire surface of the screen is made a region through which polarized light in the vertical direction is transmitted. Can be. Further, the screen surface can be divided into a region for transmitting vertically polarized light and a region for transmitting horizontally polarized light. In addition, the entire surface of the screen may be a region that transmits horizontal polarized light. That is, it is possible to move the positions on the projection surface for the plurality of polarization regions, and it is also possible to change the area of the plurality of polarization regions on the projection surface.

In such a polarizing screen, if a liquid crystal projector 106 for projecting with vertical polarization and a liquid crystal projector 107 for projecting with horizontal polarization are used, these liquid crystal projectors 106 and 107 are used at the same time to mutually project light. Even if they overlap on the screen, in the area defined by the polarizing sheet 101, only the projection light of the liquid crystal projector 106 that projects vertically polarized light is reflected, and in the area defined by the polarizing sheet 102,
Only the projection light of the liquid crystal projector 107 that projects the polarized light in the horizontal direction is reflected. As a result, light projected from the two liquid crystal projectors does not interfere with each other, and two images can be displayed simultaneously and clearly on the screen.

In the case where the liquid crystal projector and the OHP are used in combination, the same effect can be obtained by using polarized light as the OHP projection light.

Next, another embodiment of the polarizing screen device according to the present invention will be described with reference to FIG. The polarizing screen 201 includes a reflective sheet and a polarizing sheet,
Only light of a predetermined polarization direction is transmitted.
The polarizing screen 201 is rotated by a rotation axis 204 extending perpendicularly to the screen surface.
And the screen holding frame 202 is
03 is supported. That is, the polarizing screen 201
Is designed to be able to rotate the entire screen surface around the rotation shaft 204. For example, the polarization directions are 90
When two liquid crystal projectors having different degrees are used as the projection device and simultaneously projected on the polarizing screen 201, the projection light of one of the liquid crystal projectors can be selectively displayed on the polarizing screen 201 depending on the polarization direction of the polarizing sheet. it can. That is, by rotating the polarizing screen 201 about the rotation axis 204, the polarization direction of the polarizing screen is changed, whereby the projection light of one of the liquid crystal projectors is selectively displayed on the polarizing screen 201. Further, the polarizing screen 201
Needless to say, if is rotated slowly, it is possible to obtain an effect of gradually changing from one projection light to another projection light.

Referring to FIG. 3, another embodiment of the polarizing screen device according to the present invention will be described. In the illustrated polarizing screen, both sides (the front side and the back side of the paper in FIG. 3) are used as reflection type screens. Then, a plurality of strip-shaped polarizing sheets are adhered such that both sides (front and back) have different polarization directions. That is, the polarizing screen has a structure in which a plurality of strip-shaped screens are combined. Each of the rectangular screens has a screen surface 301 that transmits vertical polarized light and a screen surface 302 that transmits horizontal polarized light. In the state shown in FIG. 3, the rectangular screen on the left side in the figure has vertical polarized light. The screen surface 301 transmitting the polarized light in the right side in the figure faces the front, and the screen surface 302 transmitting the polarized light in the horizontal direction faces the front in the strip-shaped screen on the right side in the drawing.

These strip screens are rotatably held on a rotating shaft 305 independently of each other.
05 is held by the rotating shaft holding frames 303 and 304. Therefore, when a strip screen is connected around the rotation axis 305, the screen surfaces 301 and 302 can be selectively set to the front side.

As described above, by rotating the strip-shaped screen, the polarization direction of a part or the entire surface of the screen constituted by the entire strip-shaped screen can be changed.

[0025]

As described above, in the present invention, the polarization direction is changed in a part or the whole region of the polarizing screen. Therefore, a plurality of polarization directions having different polarization directions do not interfere with each other. There is an effect that projection light from a liquid crystal projector or the like, that is, an image can be clearly displayed.

[Brief description of the drawings]

FIGS. 1A and 1B are views showing a first embodiment of a polarizing screen device according to the present invention, wherein FIG. 1A is a front view, and FIG.

FIG. 2 is a view showing a second embodiment of the polarizing screen device according to the present invention, wherein (a) is a front view and (b) is a side view.

FIG. 3 is a view showing a third embodiment of the polarizing screen device according to the present invention.

FIG. 4 is a view showing a conventional polarizing screen device;
(A) is a front view, (b) is a CD line sectional view.

DESCRIPTION OF SYMBOLS 101, 102 Polarizing sheet 103 Reflecting sheet 104, 105 Take-up roll 106, 107 Liquid crystal projector 201 Polarizing screen 202 Screen holding frame 203 Screen base 204 Rotation axis 301, 302 Screen surface 303, 304 Rotation axis holding frame 305 Rotation axis 401 Polarizing screen 402 Screen base 403 Polarizing sheet 404 Reflecting sheet 405 Screen holding frame

Claims (4)

(57) [Claims] 1. A polarizing screen device used for displaying a projected image, comprising: a polarizing screen in which a plurality of regions having different polarization directions are defined as a polarizing region; and positions of the plurality of polarizing regions on a projection surface. And a moving means for moving the polarizing screen. 2. A polarizing screen device used for displaying a projected image, comprising: a polarizing screen in which a plurality of regions having different polarization directions are defined as a polarizing region; and a plurality of polarizing regions on a projection surface thereof. Changing means for changing an occupied area. 3. A polarizing screen having a predetermined polarization direction and being used with two projection devices having polarization directions different from each other by 90 degrees, and rotating the polarization screen about an axis perpendicular to the polarization screen plane. Rotating means for selectively displaying, on the polarizing screen, projection images simultaneously projected from the two projection devices. 4. A polarizing screen device used for displaying a projected image, comprising: a polarizing screen having a plurality of polarizing screen portions extending in a predetermined direction; and an axis extending in the predetermined direction independently of the polarizing screen portions. Rotating means for rotating the polarizing screen part around, and the polarizing screen portion has first and second principal surfaces, and the polarization directions of the first and second principal surfaces are different from each other. Polarizing screen device.