JPH01170178A - Projection type color display - Google Patents

Abstract

PURPOSE:To improve the luminance of a projection type color display by adding the projecting tube of one of red, green and blue colors further to the red, green and blue projecting tubes, and arranging the projecting rubes of the same color in a symmetric position up and down or right and left. CONSTITUTION:To the three-tube system projection type color display to have a red projecting tube 1R, a green projecting tube 1G and a blue projecting tube 1B, one blue projecting tube 1B' is added. For the arrangement of the projecting tubes, the green tube 1G and red tube 1R are arranged at the right and left of a central part, and two blue projecting tubes 1B and 1B' are arranged at the outer side of the green tube 1G and red tube 1R. Since the blue projecting tubes 1B and 1B' are arranged symmetrically to a central axis to connect a screen and a projector, a chromaticity change due to a position to watch is small. Since the red and green projecting tubes 1R and 1G are little dislocated from the central axis, the chromaticity change is small.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multi-tube projection color display device using a plurality of color projection tubes.

2. Description of the Related Art A conventional projection type color display is shown in FIG. In the figure, the most common type of projection color display device uses three projection tubes IR, IG, and IB that emit the three primary colors of light, red, green, and blue, to project an enlarged image onto a screen 3. , a monochromatic projection tube IR with phosphors in each of the primary colors of red, green, and blue.

This is a device that projects and enlarges the images of IG and IB onto a screen 3 using lenses 2R, 2G, and 2B. The arrangement of projection tubes IR, IG, and IB is shown in the same figure.

As shown in c and d, there are single-row, single-row, and delta arrangements.

Problems to be Solved by the Invention In FIG. 3, the brightness Bs on the screen 3 is approximately given by the following equation.

BS=Bc-Gs・η/4F (1+m)Bc: Brightness of projection tube, Gs Niscreen gain η: Efficiency of optical system
F, lens brightness m: Image magnification ratio According to the above formula, in order to increase the brightness of the screen image of the projection device, the screen gain Gs can be increased or the size of each projection tube can be made thicker (by which the image magnification ratio can be decreased). Alternatively, it is necessary to increase the lens aperture and decrease the lens brightness F, or increase the brightness of the projection tube.

In view of the above problems, the present invention provides a projection type color display device with high light output.

Means to solve problems The projection type color display device of the present invention is red.

In addition to the green and blue projection tubes, a projection tube of any color such as blue is added to configure the device with a total of four projection tubes, and the projection tubes of the same color are placed above and below in the arrangement of the four projection tubes. Or they are placed in symmetrical positions on the left and right.

Function The present invention enables the brightness of a projection type color display device to be improved by adding projection tubes of the same color with the above configuration, and also enables well-balanced projection by its special arrangement.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1a is a block diagram of the main parts of a projection type color display device according to the present invention, and also shows a layout block diagram of a projection tube. One blue projection tube IB' is added to the conventional three-tube projection color display device, resulting in a total of four projection tubes.

The projection tube arrangement is green tube IG on the left and right of the center part.

The red tubes IR are lined up, and two blue projection tubes IB and IB' are placed outside the green tube IG and red tube IR. Second
The figure shows the drive voltage (drive current) versus light emission (brightness) characteristics of the projection tube.

As shown in FIG. 2, the light emitting characteristics of current blue projection tubes are worse than those of red and green projection tubes, and have the characteristic of being saturated, especially in the high brightness range.

In the present invention, two blue projection tubes IB and IB' are arranged as shown in FIG. 1 in order to improve the saturation characteristics of the blue projection tube in a high brightness region.

When considering the arrangement of the projection tube here, there is a drawback that if the angle of incidence on the screen is different, the chromaticity changes greatly depending on the viewing angle.

In order to solve the above-mentioned drawbacks, the present invention increases the number of blue projection tubes and arranges the projection tubes as shown in FIG.

First, since the blue projection tubes IB and IB' are arranged symmetrically with respect to the central axis connecting the screen and the projector, there is no change in chromaticity depending on the viewing position. Red and green projection tube IR.

Since IG has a small deviation from the central axis, there are few historical changes. As a result, changes in the overall white balance can be reduced.

Effects of the Invention As described above, the present invention aims to improve the brightness of a projection type color display, and can provide a high-quality image with little change in chromaticity (changes in white balance depending on the position of the viewer can be improved).

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of a projection type color display according to the present invention, Fig. 2 is a drive voltage versus light emission characteristic diagram of a projection tube, and Fig. 3 is a block diagram of main parts of a conventional projection type color display and projection. It is a layout block diagram of a pipe|tube. IR...Red projection tube, IG...Green projection tube, IB, IB'...Blue projection tube, 2R...
...Red projection lens, 2G...Green projection lens, 2B, 2B'...Blue projection lens, 3...
··screen. Name of agent Patent attorney Toshio Nakao and 1 other person Fig. 1 Ifj, Il'--Ichishi@8 Shamei IR--I red I/ Fig. 2 Dora 4A C is 1tvp-p] Fig. 3 (a /]

Claims (1)

[Claims] Four projection tubes each projecting three different colored lights of red, green, and blue are provided, including two monochromatic projection tubes of any color, and four monochromatic projection tubes of the two same colors are provided. A projection type color display device characterized in that it is arranged symmetrically with respect to central axes in the horizontal and vertical directions passing through the center of the entire configuration.