JPS58134592A - Projection type color television device - Google Patents

Abstract

PURPOSE:To suppress the effect of optical chromatic aberration being remarkable at the surrounding of picture and to decrease the reduction in lightness, by arranging a ring color filter before or after a lens or a reflecting mirror of the optical system. CONSTITUTION:The device consists of a signal color CRT2, a lens 3, a color filter 1 and a reflecting mirror 4. The filter 1 has a ring or equivalent shape and effect so as to narrow the wavelength region of a single color forming the circumference of picture. Thus, the effect of chromatic aberration of the optical system is not remarkable around the projected color picture and the reduction in lightness is kept within 10%. Thus, a projection type color TV device being simple and less-expensive is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a simple and inexpensive projection type color television set that suppresses the adverse effects of chromatic aberration of an optical system in the periphery of a projected color image and avoids a decrease in the overall light amount.

A dosage-type color television system combines red, edge, and blue monochromatic cathode ray tube images into a single color image using an optical system consisting of lenses, reflectors, and the like, and projects the resulting image on a screen in an enlarged manner. At that time, due to chromatic aberration of the lens or reflective mirror,
Blurredness or color unevenness may occur around the image, or color purity: 1
This may result in a decrease in client trust.

There are various solutions to these problems, and a fundamental solution would be to use lenses and reflectors that do not have chromatic aberration, such as a combination of glass made of VSS material, but this would be subject to structural restrictions and would be expensive. or Also, since chromatic aberration occurs because the q# characteristics of the optical system differ depending on the line length, it should be effective to narrow the spectral distribution of the "monochromatic light" from the monochromatic cathode ray tube for each primary color. .

Red for color cathode ray tubes, which is currently widely used.

Green and blue phosphors both have fairly wide emission spectral distributions, so it is conceivable that they could be replaced with phosphors with narrower emission spectral distributions, but if a narrow phosphor does not exist or exists, However, there are other fundamental technical problems, such as a significant drop in luminous efficiency. In order to narrow the spectral distribution of monochromatic light, it is conceivable to leave the phosphor as it is and apply a color filter with a narrow wavelength range for each color, but the absorption by the filter is large and bright This is not very practical as the quality will be significantly reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a projection type color television display device V that is simple and inexpensive, with no concern about chromatic aberration of the optical system even in the periphery of a projected color image, with little reduction in overall brightness. It's about doing.

In order to achieve the above-mentioned purpose, in this project, we focused on the fact that chromatic aberration is particularly noticeable around the periphery of lenses and reflecting mirrors, and we focused on Color filters having a ring shape or a similar shape and effect are arranged to narrowly limit the wavelength range of the monochromatic light that forms the peripheral area of the image.

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a color filter according to the present invention. In aio, l is a color filter, 2 is a monochromatic color filter, a tube, 3 is a lens, and 4 is a reflecting mirror. By setting K in this way, the influence of chromatic aberration of the optical system becomes less noticeable in the peripheral area of the projected color image, and the reduction in brightness can be kept within 10 Is.

As explained above, according to the present invention, the influence of optical system chromatic aberration, which is particularly noticeable at the periphery of the image of a projection type color television set, can be suppressed by an extremely simple means, and the brightness can also be reduced. It can be stopped in a small way.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a color filter according to the present invention. l...ring-shaped color filter, 2...monochromatic cathode ray tube, 3...lens, 4...reflector. 1st] or□/

Claims (1)

[Claims] In a dosing type color television display device consisting of a monochromatic cathode ray tube for each primary color and an optical system that overlaps the ij planes of these cathode ray tubes and enlarges and projects the image onto a screen as one color television screen, the monochromatic cathode ray tube for each primary color is optical system,
A dosing-type color television set in which a ring-shaped color filter is arranged before or after a lens or a reflecting mirror to narrow the wavelength range of monochromatic light that forms the peripheral part of an image.