JPH0237896A - Projection type television - Google Patents

Abstract

PURPOSE:To obtain a picture which color shading and is excellent in color balance by coating and coloring with the color which has the complementary relation nearly to the light emitting color of a single color video display tube closet to the inner wall surface on the inner wall surface of an enclosure. CONSTITUTION:When single color light emitting displaying tubes 1-3 are arranged in the sequence of red, green and blue from left in an enclosure 8, an inner wall surface 9 at the side to provide a red light emitting displaying tube 1 is coated to the blue of the complementary color to the red, the reflection of the red light is vanished, further, the blue wavelength component included in the red light is reflected, the blue light to come from a blue light emitting displaying tube 3 is also reflected, and the screen picture at the side to provide the red light emitting displaying tube 1 becomes red and such a phenomenon is cancelled. In the same way, it is cancelled that the red coating is executed at an inner wall surface 10 at the blue light emitting displaying tube 3 side and the screen picture becomes blue at this side. Thus, the color shading is simple cancelled and the picture excellent in the color balance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a projection television that enlarges and projects an image displayed on a relatively small CRT or the like to obtain a large screen.

2. Description of the Related Art In general, a projection television uses three monochromatic display tubes that emit red, green, and blue light, and the images projected on the tubes are projected onto a screen 13-1 using a projection lens paired with each monochromatic display tube. A color image is obtained by projecting an image onto a screen and superimposing the three primary colors on the screen. In an integrated projection television, the above-mentioned monochrome display tube, projection lens,
Transparent type sufu! Bentos and other items are stored here. The outline is shown in Figures 3A and 3B. A is a side sectional view, and δ is a front perspective view.

In the front view, there are monochromatic light emitting display tubes 11, 12, 13, red on the left, green in the center, and blue on the right, respectively, and a projection lens 14.
15.16 are located. In this way, the red, green, and blue image light sources are separated and the respective images are projected onto the screen 16 from different directions and angles by the three projection lenses, so when viewing the screen from the front, for example, When the red light emitting display tube 11 is placed on the left side and the blue light emitting display tube 13 is placed on the right side, a phenomenon called color shading occurs in which the left side of the screen appears reddish and the right side appears bluish. do. Conventional countermeasures for this phenomenon include installing an aperture just in front of the projection lens to block part of the light rays, and pasting black paper on the end of the reflection mirror to block part of the light rays. This reduces the amount of red and blue light, suppressing the phenomenon described above.

Problems to be Solved by the Invention In order to solve the phenomenon that the left or right side of the screen becomes reddish or bluish due to the arrangement of display tubes, conventionally, red and blue light rays have been used. This method cuts part of the light rays, so a bright lens is used to obtain a bright screen, and the display tube is made more This is contrary to the idea of emitting bright light.

Also, even if the color balance is well-balanced when viewed from the front using this method, when the screen is viewed from an angle,
The phenomenon of color unevenness occurring at the periphery of the screen still remains.

The present invention effectively solves these problems in an extremely simple manner and provides a projection television with excellent color balance.

Means for Solving the Problems In order to solve the above-mentioned problems, in the present invention,
The inner wall surface of the enclosure is colored by a method such as painting in a color that is close to the complementary color of the monochromatic luminescent display tube closest to the wall surface, and by using the properties of complementary colors, for example, if red light is A blue light emitting display tube is painted blue to absorb the red wavelength component included in the light spectrum and actively reflect the blue wavelength component included in the red light, albeit slightly. The inner walls on the sides are painted red to absorb blue wavelength components and actively reflect red wavelength components.

The reason why an object appears red when irradiated with white light is because the red wavelength component contained in the white light component is extremely strongly reflected, while other wavelength components are absorbed. Therefore, if red light is used to illuminate a blue object, if the light does not contain any blue wavelength components, the object will appear black.Using this physical phenomenon, the box absorbs harmful rays of light. Efforts have been made to eliminate color unevenness on the screen.

For example, if monochromatic luminescent display tubes are arranged in the order of red, green, and blue from the left inside the case, the red light from the red display tube closest to the left inner wall will be stronger than the green or blue light. Because the light is reflected more strongly, the left side of the screen appears reddish due to the reflected light. In order to solve this phenomenon, the inner wall surface on the side where the red light emitting display tube is placed was painted blue, which is a complementary color to red, to eliminate the reflection of red light, and to further eliminate the blue wavelengths contained in red light. It also reflects the blue light coming from the blue light emitting display tube, eliminating the reddish appearance of the screen on the side where the red light emitting display tube is placed.

Similarly, the inner wall surface on the blue light emitting display tube side is painted red to eliminate the bluish tinge on the screen on this side.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing the optical arrangement relationship of red 1, green 2, and blue 3 monochromatic light emitting display tubes, projection lenses 4, 5, 6, and transmission screen 7. is omitted and drawn as a straight line. The monochromatic images of each field, green, and blue are projected onto the transmission screen 7 in a size slightly larger than the screen size. For example, if the screen size is 40 inches, the image will be projected at 42 to 44 inches, which is approximately 5 to 10% larger, to prevent image loss.

In FIG. 1, a housing 8 is added to FIG. 2, and a horizontal cross-sectional shape is depicted. Acrylic resin material is generally used as the material for the transmission screen 7 on which images are projected by the projection lens groups 4, 5, and 6. Note that the transmissive type IJ+n 7 contains a diffusing material and is semitransparent. Throw it onto the transparent screen 7
In the mapped image, the screen surface becomes a secondary light emitting surface, and light rays are emitted in various directions from the front surface according to its light distribution characteristics, reaching the viewer. Approximately 4% of light is reflected from an acrylic surface in the air. Approximately 4% of the light rays projected onto the transmission screen 7 are reflected inside the casing on the back surface of the screen, becoming unnecessary light and causing a reduction in image contrast. For example, if we pick up and draw a certain ray out of the rays emitted from the projection lens 4.5.6, the first
As shown in the figure, the light rays R, Q, and B are transmitted through a transmission screen 7.
is incident on the back surface of the
% of the light is reflected, reaches the inner wall surface 9 of the enclosure through the path shown in the figure, and illuminates this surface. Also, as mentioned above, the projected image is larger than the screen size, so
The light projected to the outside of the screen directly illuminates the side walls or top surface inside the enclosure 8. The inside of the casing is usually painted black to prevent internal reflection.
However, a small amount of light is reflected. Among the red, green, and blue light rays reflected by the inner wall surface 9 of the housing, the red light ray emitted from the projection lens 4 closest to the inner wall surface 9 has the strongest reflection intensity. (Since the intensity of the light beam is attenuated in inverse proportion to the square of the distance from the light source, the optical path distance for the red light ray to reach the inner wall surface 9 is the shortest compared to other light rays.) The reflected light in the surrounding area becomes slightly reddish. As a result, when the transmissive screen 7 is observed from the front, the left side of the screen appears reddish. Also, for the same reason, the left side appears bluish.

This configuration solves this phenomenon (color shape ink) in an extremely simple manner.

The left inner wall surface 9 of the enclosure 8 is painted with a dark blue color, and the right inner wall surface 10 is painted with a dark red color.

As mentioned above, the light is reflected on the back surface of the transmissive screen 7,
Since the inner wall surface 9 is painted blue, the blue wavelength components contained in each color light beam are reflected, and the other wavelength components are reflected. Absorbed. As a result, the reflected light around the left inner wall surface 9 becomes bluish, and similarly, the light reflected around the left inner wall surface 9 becomes bluish.
Since it is painted red, the reflected light around this area will have a reddish tinge. For this reason, when the inside of the enclosure was painted black on the front, the phenomenon in which the left side of the screen appeared reddish and the right side appeared bluish was neutralized due to the above-mentioned reasons, and projection without color shading and color unevenness was eliminated. You can get the screen. Note that the inner wall surface may be colored by pasting colored paper or plastic sheets.

Effects of the Invention As is clear from the above explanation, the present invention solves the so-called coloring phenomenon in which both sides of the screen appear reddish or bluish in a three-tube projection television using an extremely simple method. It is possible to obtain a well-balanced image.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a projection television according to an embodiment of the present invention, FIG. 2 is a schematic plan view showing the configuration of the projection television, and FIG. 3 A1B is a general three-tube projection television. FIG. 3 is a side cross-sectional view and a front perspective view showing the arrangement of a color-emitting display tube, a projection lens, a transmission screen, and a reflection mirror in the case. 1.2.3... Monochrome luminescent display tube, 4.5.6.
...Projection lens, 7... Transmissive screen, 8... Enclosure, 9... Wall surface of the enclosure (
left), 1o...inner wall surface of the enclosure (right), R...
...Red ray, G...Green ray, Sun...
・Blue rays. Name of agent: Patent attorney Shigetaka Awano and one other person Figure 57〇-

Claims (2)

[Claims] (1) Each monochrome video display tube on which an image is displayed in red, green, and blue colors, and a projection lens paired with each monochrome video display tube that projects the image to be projected on the monochrome video display tube. , comprising a transmission screen that forms an image projected by the projection lens, and a housing in which the plurality of monochrome video display tubes and the projection lens are housed and the transmission screen is attached, the housing A projection television characterized in that the inner wall surface of the projection television is painted with a color that is close to the color of the light emitted by the monochrome video display tube closest to the inner wall surface and the auxiliary color. (2) The projection television according to claim 1, wherein colored paper or plastic sheet is pasted on the inner wall surface of the casing.