KR100669675B1 - Projection TV - Google Patents

Abstract

According to the present invention, a red color cathode ray tube, a green color cathode ray tube, and a blue color cathode ray tube; First and second mirrors for synthesizing and reflecting the images projected from the respective color cathode ray tubes; And a screen on which the image reflected from the second mirror is projected thereon, wherein the size of the blue color cathode ray tube is larger than that of the red color cathode ray tube and the green color cathode ray tube. Projection televisions are provided.

Description

Projection TV

1 is a schematic cross-sectional view of a color cathode ray tube for a typical projection television.

2 is a schematic diagram of a typical projection television.

3 is a schematic configuration diagram of a color cathode ray tube provided in the projection television of FIG. 2;

4 is a schematic configuration diagram of a color cathode ray tube provided in the projection television according to the present invention;

<Brief Description of Major Codes in Drawings>

11. Cathode ray tube 12. Refrigerant frame

17. Refrigerant

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection television, and more particularly, to a projection display device configured to have different sizes of color cathode ray tubes provided in a projection television.

Projection televisions are typically equipped with three projection color cathode ray tubes. It forms images of the three primary colors of light, red, green, and blue colors, respectively, through three cathode ray tubes, and magnifies, synthesizes, and reflects the images through lenses and mirrors. To make it visible on the screen. Projection televisions include two types, a front projection type and a rear projection type. The front projection type allows the image enlarged through the lens to be viewed directly on the reflective screen, while the rear projection type reflects the image enlarged through the lens through the mirror and then projects it onto a separately installed screen. It was made to see.

Figure 1 shows a schematic cross-sectional view of a typical projection color cathode ray tube provided in a projection television.

Referring to the drawings, the refrigerant frame 12 is installed in front of the panel of the cathode ray tube body 11, and the lens frame 13 is installed in front of the refrigerant frame 12. Inside the refrigerant frame 12, a refrigerant 17 is filled in the space formed between the front panel of the cathode ray tube body 11 and the lens 14a. The sealing members 15 and 16 prevent the leakage of the refrigerant. A plurality of lenses 14a to 14e may be installed in the lens frame 13. In the operation of such a projected color cathode ray tube, an image formed from the cathode ray tube body 11 is enlarged through a plurality of lenses, wherein heat generated in the cathode ray tube body 11 is cooled by the refrigerant 17. Typically, projection televisions are provided with three projection color cathode ray tubes as shown in FIG. 1 to correspond to the colors of red, green and blue.

2 is a schematic overall configuration diagram of a projection television that is a projection display device, and FIG. 3 shows a part of FIG. 2.

Referring to FIG. 2, the projection display device includes an optical system 24 and an optical system 24 for enlarging and projecting an image formed in the cathode ray tube 23 and the cathode ray tube 23 in the cabinet 26. A first mirror 21 for synthesizing and reflecting the projected images, a second mirror 22, and a screen 25 for a user to view the image reflected from the second mirror 22; . The optical system 24 includes a lens frame 13 and lenses installed therein in FIG. 1.

3, it can be seen that an image is projected from the three color cathode ray tubes 23a, 23b, and 23c of red, green, and blue with respect to the first mirror 21. That is, the reference numeral 23 in FIG. 2 shows three color cathode ray tubes in practice, and the optical systems 24a, 24b and 24c are predetermined at the same height for each color cathode ray tube 23a, 23b, and 23c. Are placed with an angle.

In the projection television as described above, since each color cathode ray tube 23a, 23b, 23c must be made compact and can realize high brightness, high voltage and high current density are formed in the color cathode ray tube as compared with the direct view type cathode ray tube. Therefore, the phosphors provided in each color cathode ray tube must maintain high luminance characteristics. Among the phosphors currently developed, in the case of blue, ZnS: Ag.Al or ZnS: Ag, Cl phosphors are used. However, the high brightness characteristics of these phosphors are inferior to other red and green phosphors, resulting in deterioration of the quality of the image itself formed on the screen 25 of the projection television. That is, the quality of the synthesized image can be ensured only when the high luminance characteristics at the high current density are uniform for the red, green, and blue phosphors, but the quality of the synthesized image is poor because the high luminance characteristics of the blue phosphors are relatively inferior. This is not guaranteed.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a projection television that can improve the quality of the image.

In order to achieve the above object, according to the present invention, a red color cathode ray tube, a green color cathode ray tube, and a blue color cathode ray tube; First and second mirrors for synthesizing and reflecting the images projected from the respective color cathode ray tubes; And a screen on which the image reflected from the second mirror is projected thereon, wherein the size of the blue color cathode ray tube is larger than that of the red color cathode ray tube and the green color cathode ray tube. Projection televisions are provided.

According to another feature of the invention, the size of the blue color cathode ray tube is 9 inches, the size of the red color cathode ray tube and the green color cathode ray tube is 7 inches.

According to another feature of the invention, ZnS: Cu, Al is provided as a phosphor as a phosphor of the green color cathode ray tube.

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

The overall configuration of the projection television according to the present invention is similar to that described with reference to FIG. That is, the cathode 26 and the optical system 24 for enlarging and projecting an image formed in the cathode ray tube 23 and the image projected through the optical system 24 are synthesized and reflected inside the cabinet 26. And a first mirror 21, a second mirror 22, and a screen 25 on which a user can view an image reflected from the second mirror 22.

4 is a schematic configuration diagram of a color cathode ray tube or the like provided in the projection television according to the present invention.

Referring to the drawings, the projection television according to the present invention is provided with a red color cathode ray tube 43a, a green color cathode ray tube 43b, and a blue color cathode ray tube 43c, and corresponds to each of the color cathode ray tubes in accordance with an optical system ( 44a, 44b, 44c are disposed. The images projected from the color cathode ray tubes 43a, 43b, 43c are projected onto the first mirror 21, and are reflected back to the screen 25 through the second mirror 22 as shown in FIG.

According to a feature of the invention, the respective color cathode ray tubes are configured differently in size. That is, as described above, since the blue color cathode ray tube 43c has high luminance characteristics inferior to the other red and green color cathode ray tubes 43a and 43b, the other color cathode ray tubes are applied when a relatively large size is applied. And high brightness characteristics can be maintained.

For example, in a projection television having a screen of 40 inches or larger, the red and green color cathode ray tubes 43a and 43b have a size of 7 inches, whereas the blue color cathode ray tube 43c is larger than this. Configure it to have an inch size. At this time, the phosphor used for each color cathode ray tube is a red color cathode ray tube 43a is Y ₂ 0 ₃ : Eu phosphor, and the green color cathode ray tube 43b is YAG + P1 + Y-silicate mixed phosphor, blue color cathode ray tube 43c. ) May be fabricated using ZnS: Ag, Al phosphors, or alternatively, other phosphors may be used. (YAG is Y ₃ (Al, GA) ₅ O ₁₂ : Ce ³⁺ , Pl is Zn ₂ Si ₄ : Mn ²⁺ , Y-silicate is Y ₂ SiO ₅ : Tb ³⁺ .

In the case of using the above phosphor and having different color cathode ray tube sizes, the respective luminance and color coordinate characteristics are compared as follows.

First, the following comparative example is the case where the size of each color cathode ray tube is comprised equally, and the fluorescent substance enumerated above was used, and it corresponds to the case of a normal projection television.

Comparative Example

 Red  Green  blue Luminance (cd / m ² ) 1mA / cm ²  12790 32890  4020 Color coordinates (x / y)  0.666 / 0.332 0.336 / 0.581  0.141 / 0.055 Saturation  0.96  0.99.  0.50

The first embodiment is a case where the size of the color cathode ray tube of red and green is 7 inches, and the size of the color cathode ray tube of blue is 9 inches.

<First Embodiment>

 Red  Green  blue Luminance (cd / m ² ) 1mA / cm ²  12790 32890  5500 Color coordinates (x / y)  0.666 / 0.332 0.336 / 0.581  0.141 / 0.055 Saturation  0.96  0.99.  0.70

Comparing the comparative example and the first embodiment, it can be seen that the luminance and saturation of blue were further increased in the first embodiment. In other words, a higher quality image can be obtained by increasing the size of the blue color cathode ray tube.

In the second embodiment, the color cathode ray tube size of red and green is 7 inches, the color cathode ray tube size of blue is 9 inches, and the phosphors provided in the color cathode ray tube of green are ZnS: Cu, Al. This is the case.

Second Embodiment

 Red  Green  blue Luminance (cd / m ² ) 1mA / cm ²  12790 33000  5500 Color coordinates (x / y)  0.666 / 0.332 0.300 / 0.610  0.141 / 0.055 Saturation  0.96  0.95  0.7

In the case of the second embodiment, it can be seen that the luminance is somewhat improved in the color cathode ray tube of green. That is, it can be seen that better image can be obtained by using ZnS: Cu, Al as the phosphor of the green color cathode ray tube and increasing the size of the blue color cathode ray tube.

In the above table, the saturation means the luminance emission saturation characteristics according to the amount of electrons that are the light emitting source of the phosphor. It is mainly expressed in γ, and evaluation conditions vary depending on the display and the phosphor. The closer the value is to 1, the better the saturation of the phosphor, and therefore, the saturation of the blue phosphor is better in the first and second embodiments than in the comparative example. In addition, it can be seen that the first embodiment and the second embodiment have better luminance characteristics in the high current region than the comparative example.

On the other hand, the phosphors have inherent saturation characteristics for each kind. For example, ZnS: Cu, Al has a saturation of 0.67 and Y ₂ SiO ₅ : Tb ³⁺ has a saturation of 0.98. ZnSiO ₄ : Mn ²⁺ has a saturation of 0.85 and Y ₃ Al ₃ Ga ₂ O ₂ : Tb ³⁺ Has a saturation of 0.97. Therefore, the properties change depending on the degree of mixing.

In the projection television according to the present invention, among the three projected color cathode ray tubes, a blue color cathode ray tube size, in which the luminance characteristic is deteriorated at a relatively high current density, is made larger than other color cathode ray tubes to obtain an overall improved screen image. The advantage is that you can. In addition, the luminance of the green color cathode ray tube can be improved by selecting a phosphor provided in the green color cathode ray tube as a specific one.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, it is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Could be. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (3)

Red color cathode ray tube, green color cathode ray tube and, blue color cathode ray tube; First and second mirrors for synthesizing and reflecting the images projected from the respective color cathode ray tubes; A projection television comprising: a screen on which an image reflected from the second mirror is projected thereto; And the size of the blue color cathode ray tube is larger than that of the red color cathode ray tube and the green color cathode ray tube. The projection television according to claim 1, wherein the size of the blue color cathode ray tube is 9 inches, and the size of the red color cathode ray tube and the green color cathode ray tube is 7 inches. The projection television according to claim 1, wherein ZnS: Cu, Al is provided as a phosphor of the green color cathode ray tube.

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