KR100403509B1 - Apparatus for compensating for color illumination in a projection TV - Google Patents

Abstract

In the projection television that compensates for the color non-uniformity according to the present invention, the light on one side of the C-lens is removed in order to remove color non-uniformity caused by different beam distributions emitted from the R, G, and B projection type cathode ray tubes due to various causes. It is provided with a color correction means that can block the. The color correction means may include the C-lens to which at least one beam blocking band is attached, a C-lens coated with one or more beam blocking points on one side, or at least one beam blocking band on one side. It features a coated C-lens.

According to the present invention, a clear image quality is achieved by eliminating color unevenness on the left and right screens of a conventional large screen, and the distance between the lens and the screen that determines the volume of a conventional projection TV set is maintained. Minimizing the increase in volume has the effect.

Description

Apparatus for compensating for color illumination in a projection TV}

The present invention relates to a projection television that compensates for color non-uniformity by providing color correction means on one side of the C-lens to remove a part of the strong beam emitted from the R and B projection type cathode ray tubes in order to reduce color unevenness occurring in the projection television. will be.

Looking at the structure of a conventional projection television, a small projection cathode ray tube is used as an image source, and a single tube type in which an image generated from one projection cathode ray tube is simply passed through a projection lens and enlarged, as shown in FIG. Similarly, beams emitted from three independent projection cathode ray tubes 101, 102 and 103 of R (red), G (green) and B (blue) are incident on each projection lens 104 and through the projection lens There is a trigonometry that implements color images on the screen by projecting onto and allowing the images to be synthesized.

According to Fig. 1, in the conventional three-tube type projection television, projection cathode ray tubes 101 and 103 which process R (red) and B (blue) are located on both sides of the G cathode ray tube 102 located at the optical axis center 106. The projection cathode ray tubes 101 and 103 maintain the shape of a body line having a constant placement angle with each other.

Accordingly, as shown in FIG. 3A, the projection cathode ray tubes 302a and 304a of the R and B which are separated from the optical axis center 301a maintain a constant arrangement angle, so that the beams are emitted from the respective projection lenses 306a. This results in the distances reaching each screen not being equal.

That is, the illuminance distribution of the beam appears differently on the screen 307a according to the angle formed by the beam segment emitted from the projection lens 306a and the normal on the screen.

Accordingly, the distribution of the beams emitted from the R, G, and B projection cathode ray tubes 302a, 303a, and 304a are distributed differently on the screen, resulting in color unevenness on the left and right of the screen 307a.

In particular, the problem related to color irregularity as described above has not been presented as a big problem in a conventional small screen, but has been presented as a big problem in a large screen developed in recent years according to the needs of consumers.

The present invention has been proposed to solve the above problems, to provide a color correction means for blocking a part of the beam emitted from the projection type cathode ray tube of R, B respectively located on both sides of the central axis on the screen, a large screen By eliminating the left and right color unevenness on the screen that can occur in, the purpose is to implement a better image quality.

1 is a perspective view of main parts of a conventional projection television

2 is a cross-sectional view showing a fastening structure of a projection lens of a conventional projection television.

3A is an illuminance distribution diagram of a beam in a case where no color correction means is mounted;

3B is an illuminance distribution diagram of the beam in the case where the color correction means is mounted;

4a shows a first preferred embodiment according to the invention

4b shows a second preferred embodiment according to the invention

4c is a third preferred embodiment according to the present invention

* Explanation of symbols for main parts of the drawings

203: C-lens 402a: beam blocking band

402b: beam blocking coating point 402c: beam blocking coating strip

Hereinafter, the present invention will be described with reference to the accompanying drawings, but after briefly explaining the C-lens to be described below, the present invention will be described in detail.

FIG. 2 is a view illustrating a fastening structure of a conventional projection lens, in which a lens barrel (20) is fastened to one side of a coupler (208) to fasten the CRT glass bulb (201) to form a fluorescent surface, and to protrude to the coupler (208) to the other side. The first, second, third and fourth lenses 203 to 207 are disposed at predetermined intervals from the front surface of the CRT glass bulb by being fastened to the inner circumferential surface of the lens barrel 202 and the lens barrel 202.

A typical projection lens is composed of a total of five to four, wherein Figure 2 is

5 is a schematic view showing a five-element projection lens structure, including a first lens 207 and a first lens.

The second lens 206 and the fourth lens 204 are made of aspherical plastic lenses, the third lens 205 is a glass lens, and the fifth lens 203 is also referred to as a field lens as a C-lens. The C-lens 203 is formed of a dish-shaped convex-convex lens and is configured to correct image curvature and distortion aberration.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

4A is a side view and a front view showing a first embodiment of a projection television that compensates for color imbalance according to the present invention, wherein the R and B projection type cathode ray tubes 302a and 304a are provided on one side of the C-lens 401a. A band 402a is attached to block a part of the beam emitted from the beam, and the beam blocking band corresponds to a portion 304b of the maximum left and right of the screen in the illuminance distribution diagram of FIG. 3B. Attach to any position of.

In other words, the beam emitted from the R (B) projection type cathode ray tube reduces the strong portion 304b to the thick dashed portion 303b in comparison with the beam projected from the B (R) projection type cathode ray tube. The strip 402a is attached to one side.

The strip 402a may be made of any material capable of blocking light, and the material is preferably steel.

Fig. 4B is a side view and front view showing a second embodiment of the present invention, in which the beam-blocking points 402b of a certain shape are blocked in order to block a part of the beam emitted from the cathode ray tubes 302a and 304a. Coating on one side of the lens (401b).

At this time, it is preferable to coat at a position corresponding to the portion 304b forming the maximum left and right of the roughness distribution diagram of FIG. 3B.

In the second embodiment of FIG. 4B, a more detailed illuminance distribution can be manipulated by manipulating a distribution of beam blocking points 402b of a certain shape.

FIG. 4C is a further application of the present invention, in which at least one stripe is coated on one side of the C-lens to block a portion of the strong beam exiting the R, B projection cathode ray tubes 302a, 304a. do.

In this case, by distributing the plurality of bands spatially in correspondence with the portion 304b of the left and right screens in the illuminance distribution diagram of FIG. 3B, a result similar to the effect of FIG. 4B may be obtained.

As described above, the projection television according to the present invention includes color correction means for blocking a part of the beam emitted from the R and B projection type cathode ray tubes. Therefore, the following effects can be obtained.

First, better image quality can be achieved by reducing the left and right color unevenness that occurs in large-screen projection TVs.

Second, the present invention maintains the distance between the lens and the screen, which determines the volume of a conventional projection TV set, to minimize the volume increase of the TV set.

Third, the main effect of lighting is to reduce the cost increase of the product by manufacturing with a simple installation structure.

Claims (4)

R and B projection cathode ray tubes are respectively located on both sides of the center axis of the screen, and the beams emitted from each of the projection cathode ray tubes are connected to the screen through a plurality of projection lenses including a coupler connected to each projection type cathode ray tube and a C-lens. In a projection television set configured to be projected, And further comprising color correction means for blocking a part of the beam emitted from the cathode ray tube. The method of claim 1, And said color correction means is said C-lens having at least one beam blocking band attached thereto. The method of claim 1, The color correction means is a projection television set that compensates for color non-uniformity, characterized in that the C-lens is coated with at least one beam blocking point on one side. The method of claim 1, And the color correction means is the C-lens with one or more beam blocking bands coated on one side thereof.