KR20050005363A - Cathode ray tube - Google Patents

Abstract

PURPOSE: A cathode ray tube is provided to prevent degradation of contrast uniformity and flatness of outer surface of a panel, while using a tilt glass having high variance of transmittance. CONSTITUTION: A cathode ray tube comprises a panel(14), a funnel(20) connected to the panel, a neck portion(18) connected to the funnel, and an electron gun(16) arranged in the neck portion along a tube axis direction. The panel has an inner surface on which a phosphor screen(12) is formed, and an outer surface having an effective screen portion formed by the phosphor screen. The panel has a diagonal effective surface end formed into a predetermined depth in a rearward direction from an X-Y plane including the center of the outer surface of the panel.

Description

Cathode Ray Tube {CATHODE RAY TUBE}

The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube having improved luminance uniformity while maintaining flatness of an outer surface of a panel.

Color cathode ray tubes used in monitors, televisions, and the like of computers emit three electron beams emitted from an electron gun to a fluorescent screen through an electron beam through hole of a shadow mask to excite the phosphor of the fluorescent screen. A display device includes a panel having a fluorescent film screen on its inner surface, a neck portion in which an electron gun is incorporated, and a vacuum bulb comprising a funnel connecting the panel and the neck portion.

In the color cathode ray tube of such a configuration, conventionally, the inner and outer surfaces of the panel are formed to have a predetermined curvature in consideration of the deflection trajectory of the electron beam, and the cathode ray tube having such an aspherical panel is not substantially flat on the outer surface of the panel. Because of this, there is a problem in that the screen distortion is severe and eye fatigue is increased. Therefore, in recent years, a flat cathode ray tube which solves the above problems by constructing the panel outer surface substantially flat has been developed.

However, the planar cathode ray tube should be formed with the same or similar curvature as the conventional one in consideration of the deflection trajectory of the glass firecracker and the electron beam, and the thickness of the panel becomes thicker from the center of the screen toward the periphery. Accordingly, the above-described thickness difference causes light absorption at the center and the periphery of the screen to be different, resulting in a difference in light transmittance at the center and the periphery of the screen, thereby degrading the brightness uniformity of the periphery from the center. There is a problem.

Therefore, in the past, tint glass having a large change in light transmittance according to a thickness change cannot be used as a panel material, and clear glass having a small change range described above is used as a panel material. Here, the tint glass refers to a glass having a light transmittance of less than 70%, the dark tint glass having a light transmittance of less than 50%, and a semi tint glass having a light transmittance of 50 to 70%. semi tint glass. In addition, clear glass refers to glass whose light transmittance is 75% or more.

A cathode ray tube manufactured using the above-described clear glass panel is disclosed in Korean Laid-Open Patent Publication No. 2002-76886.

As described above, the cathode ray tube disclosed in this patent manufactures a panel using a clear glass having a small variation in the light transmittance according to the thickness change, and forms a black filter film on the inner surface (or outer surface) of the panel to lower the overall light transmittance. This improved the transmittance difference across the screen.

However, the conventional cathode ray tube of such a configuration has a problem of adding a process by coating a black filter film on the inner surface (or outer surface) of the panel, and the manufacturing cost increases due to the addition of the process.

Therefore, in order to prevent the luminance uniformity from being lowered without increasing the manufacturing cost, a tint glass having a low light transmittance should be used. In this case, if the same panel thickness as in the above patent is maintained, clear glass is used as described above. There is a problem that the luminance uniformity is lowered compared to the manufactured panel.

In addition, when the radius of curvature of the inner surface of the panel is designed to be larger than the prior art in order to prevent the luminance uniformity from deteriorating, the radius of curvature of the shadow mask, which is a color sorting mechanism, must also be designed to be large. There is a problem of this deterioration.

Due to this problem, the cathode ray tube having a panel manufactured using the above-described tint glass has not been developed until now.

Accordingly, the present invention is to solve the above problems, while using a tint glass having a large variation in the light transmittance according to the thickness change, a panel for a cathode ray tube that can prevent the luminance uniformity and the flatness of the outer surface of the panel to be lowered For the purpose of providing it.

1 is a view showing a schematic configuration of a cathode ray tube according to an embodiment of the present invention.

2 is a front view of a panel according to an embodiment of the invention.

3 is a diagonal cross-sectional view of a panel according to an embodiment of the present invention.

4 is a graph showing the relationship between the diagonal effective surface end depth z, the diagonal outer curvature radius R and the distortion DS in the panel according to the embodiment of the present invention.

5 is a one quadrant schematic view of a panel according to an embodiment of the invention.

6 is a conceptual diagram of FIG. 5 for explaining why DS; FIG.

7 is a graph showing the amount of change in light transmittance according to the decrease in the thickness of the panel according to an embodiment of the present invention.

The present invention to achieve the above object,

An inner surface having a fluorescent screen, and an outer surface having an effective screen portion formed by the fluorescent screen, wherein a diagonal end of the effective screen portion has a constant depth z rearward from an XY plane including the center of the outer surface A panel formed as deep as;

A funnel connected to the panel and a neck portion connected to the funnel;

An electron gun mounted inside the neck portion along a tube axis direction;

The outer surface of the panel is a why (DS) that the viewer feels when looking at the end of the diagonal at any point (P) on the tube axis located in front of the panel While satisfying 1, the present invention provides a cathode ray tube formed such that the depth z satisfies Equation 2 below.

[Equation 1]

DS ≤ 1.0 mm

[Equation 2]

z ≥ 2.4 mm

In Equation 1, the dwarf DS denotes a coordinate of the end of the diagonal portion of the effective screen unit on the basis of the center of the panel outer surface as (x ', y', z), and the point P on the tube axis. Limiting the depth z at a straight line distance between the two coordinates when the coordinates of the point where the line connecting the end of the diagonal line and the diagonal end meet the XY plane are (x ", y", 0). Indicates.

In this case, the panel may be made of clear glass or tint glass. In view of the problems caused by using a black filter film, the panel may be manufactured using tint glass.

According to a preferred embodiment of the present invention, the diagonal curvature radius of the outer surface of the panel is preferably designed to be included in the range of 10,000 to 50,000 mm, preferably in the range of 25,000 to 35,000 mm.

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

1 is a view showing a schematic configuration of a planar cathode ray tube according to an embodiment of the present invention, Figures 2 and 3 show a front view and a diagonal cross-sectional view of the panel shown in FIG.

As shown, the cathode ray tube of this embodiment includes a panel 14 provided with a fluorescent film screen 12 on its inner surface, a neck portion 18 on which an electron gun 16 is mounted on its inner side, and the panel 14. And a trumpet-shaped funnel 20 connecting the neck portion 18 to each other.

Inside the panel 14, a shadow mask 22 for color-selecting the electron beam emitted from the electron gun 16 is disposed adjacent to the fluorescent screen 12 by a mask frame (not shown), and the funnel 20 is disposed. On the outside is provided a deflecting device 24 for deflecting the electron beam emitted from the electron gun 16.

In the cathode ray tube having such a configuration, the outer surface of the panel 14 has a diagonal effective surface end P1 of the effective screen portion 12 'formed by the fluorescent film screen 12 having a constant depth from the XY plane PL. It is formed by (z) rearward, that is, deep toward the electron gun 16. Here, the X-Y plane PL represents an imaginary plane including the center of the outer surface of the panel 14.

At this time, the depth z has a smaller value as the radius of curvature R of the diagonal direction (d-axis) of the outer surface of the panel 14 increases as shown in FIG. 4. FIG. 4 is a 36 "(inch) cathode ray made of semi tint glass having a light transmittance of 57% when the median thickness T of the panel 14 is 10.16 mm and a diagonal effective surface size D of 600 mm or more. In the pipe, the depth z of the diagonal effective surface end P1 according to the diagonal curvature radius R is measured.

As described above, the panel 14 having a constant curvature radius on the outer surface of the panel 14 recognizes a certain distortion (DS) when a user views an image in front of the panel 14, which is illustrated in FIGS. 5 and 6. It demonstrates with reference.

FIG. 5 is a schematic view showing one quadrant of the panel shown in FIGS. 1 to 3, and FIG. 6 is a cross-sectional view of FIG. 5 taken along a tube axis (Z) direction and a diagonal (d) direction.

Diagonal effective surface end P1 at any point P on tube axis Z away from panel 14 by a distance L1, for example, three times the horizontal effective surface size H. When viewed, the viewer perceives that the image implemented at the end P1 is deeper by a predetermined amount than the XY plane PL.

That is, on the basis of the center C of the outer surface of the panel 14, the coordinates of the diagonal effective surface end P1 are referred to as P1 (x ', y', z), and the point P on the tube axis Z is defined. ) And the coordinates of the point P2 where the line connecting the diagonal effective surface end P1 meets the XY plane () are called P2 (x ", y", 0), and the linear distance between the two coordinates When it is referred to as L, the viewer recognizes that the image implemented at the diagonal effective surface end P1 is deepened by the distance L. However, the image of the diagonal effective surface end P1 is implemented at a point substantially as deep as the depth z from the X-Y plane PL.

Therefore, the viewer enters the image implemented at the diagonal effective surface end P1 substantially deeper by the difference Lz between the straight line distance L between the two coordinates and the depth z of the diagonal effective surface end P1. It will be recognized as.

As such, the difference Lz between the actual depth z of the diagonal effective surface end P1 and the depth felt by the viewer, that is, the linear distance L between both coordinates, may be referred to as the why DS. As shown in FIG. 4, DS has a value that increases as the diagonal curvature radius R of the outer surface of the panel 14 decreases.

However, according to the naked eye observation experiment of the present inventors, it was determined that there is no problem in the flatness when the above-mentioned why (DS) satisfies the following equation (1).

[Equation 1]

DS ≤ 1.0 mm

Therefore, referring to FIG. 3, it can be seen that the diagonal curvature radius R of the outer surface of the panel 14 can be designed within a range of 100,000 mm or less with respect to the why DS. However, in the case of using a panel made of semi-tinted glass, the light transmittance is largely changed due to the change in thickness. Therefore, the design of the diagonal curvature radius (R) of the outer surface of the panel satisfies the luminance uniformity. It can't be designed smoothly. Therefore, the thickness of the diagonal effective surface end P1 should be designed to a thickness sufficient to satisfy the luminance uniformity.

7 shows the amount of improvement in transmittance according to the thickness reduction of the panel diagonal portion relative to the center. In the case of semi-tint glass, the light transmittance of the panel diagonal portion should be improved by 10% or more compared with the conventional method in order to satisfy the luminance uniformity. Therefore, referring to FIG. 6, in order to improve the light transmittance of the diagonal portion by 10% or more, it can be seen that the diagonal effective surface depth z must satisfy the following equation (2).

[Equation 2]

z ≥ 2.4 mm

Accordingly, referring to FIG. 3, a range of curvature radii that simultaneously satisfy the ranges of Equations 1 and 2 is designed to design a diagonal curvature radius R of the outer surface of the panel 14 within a range of 10,000 to 50,000 mm. In this case, it can be seen that flatness and luminance uniformity can be suppressed from being lowered.

In addition, when the panel 14 is formed to satisfy the following Equation 3, the panel 14 may more effectively eliminate the problem of deterioration of flatness. Referring to FIG. 3, the above Equations 3 and 2 may be simultaneously applied. It can be seen that the range of the satisfactory curvature radius R is 25,000 to 35,000 mm.

[Equation 3]

DS ≤ 0.5 mm

As described above, when the diagonal curvature radius of the outer surface of the panel is designed within the range of 10,000 to 50,000 mm, preferably 25,000 to 35,000 mm, the luminance uniformity can be maintained while preventing the flatness from decreasing.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

As described above, according to the cathode ray tube according to the present invention, a panel may be manufactured using tinted glass without degrading flatness and luminance uniformity. Therefore, in the case of manufacturing a panel using clear glass in the related art, a process of forming a black filter film may be removed to maintain luminance uniformity, and thus, manufacturing cost may be reduced.

Claims (6)

An inner surface having a fluorescent screen and an outer surface having an effective screen portion formed by the fluorescent screen, wherein the diagonal effective surface end P1 has a constant depth toward the rear from the XY plane including the center of the outer surface; a panel formed as deep as z); A funnel connected to the panel and a neck portion connected to the funnel; An electron gun mounted inside the neck portion along a tube axis direction; The outer surface of the panel is a why (DS) that the viewer feels when looking at the diagonal effective surface end (P1) at any point (P) on the tube axis located in front of the panel is Cathode ray tube formed so as to satisfy the following formula 1, wherein the depth (z) satisfies the following formula (2). [Equation 1] DS ≤ 1.0 mm [Equation 2] z ≥ 2.4 mm In Equation 1, the dwarf DS refers to the coordinate of the diagonal effective surface end P1 on the basis of the center of the outer surface of the panel as P1 (x ', y', z), and the point on the tube axis. The coordinate of the point P2 where the line segment connecting P and the diagonal effective surface end P1 meets the XY plane is called P2 (x ", y", 0), and the linear distance between the two coordinates When L is the difference between the distance L and the depth z. The cathode ray tube according to claim 1, wherein a diagonal radius of curvature of the outer surface of the panel is included in a range of 10,000 to 50,000 mm. The cathode ray tube according to claim 1, wherein a diagonal radius of curvature of the outer surface of the panel is included in a range of 25,000 to 35,000 mm. The cathode ray tube according to claim 1, wherein said why (DS) further satisfies Equation 3 below. [Equation 3] DS ≤ 0.5 mm The cathode ray tube according to any one of claims 1 to 4, wherein a diagonal effective surface size of the outer surface of the panel is 600 mm or more. The cathode ray tube according to any one of claims 1 to 4, wherein the panel is made of tint glass having a transmittance of 50% or more when the median thickness is 10.16 mm.