KR100447656B1 - Panel For The Flat Type CRT - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a panel for a flat CRT, and in particular, an object of the present invention is to solve a problem of deterioration in focus and purity uniformity caused when the panel is planarized.

The technical means of the present invention is a planar brown including a fluorescent surface formed with a plurality of black matrices on the inner surface, a phosphor surface coated with R, G, and B phosphors between the black matrix and the black matrix, and an anti-reflective coating on the inner surface. In the conventional panel, the antireflection film roughness distribution at the center and the peripheral portion of the panel is different.

According to the present invention, it is possible to secure a uniform luminance quality of the entire screen of the flat CRT and to minimize the internal reflectance of the panel to secure high contrast characteristics.

Description

Panel for the Flat CRT {Panel For The Flat Type CRT}

The present invention relates to a panel for a flat CRT, and in particular, in order to solve the problem of deterioration in focus and purity uniformity caused by the flattening of the panel, the illuminance distribution of the inner surface antireflection film is reduced from the center to the periphery of the panel. It relates to a flat CRT panel.

In general, CRTs are used in television receivers or video displays, and are divided into curved and flat shapes according to the shape of the screen. The curved type is closer to the actual screen, whereas the demand is gradually decreasing due to the distortion of the screen. Demand is gradually spreading.

In addition, as the structure of the CRT is gradually flattened and refined, a series of studies are performed to improve the purity of the screen, to prevent reflection of the outside surface of the panel by external light, and to minimize the reflection of light generated when the phosphor formed on the inside of the panel of the cathode ray emits light. Is actively underway.

As shown in FIG. 1, a general flat CRT includes a flat panel 3 including a fluorescent surface 1 coated with R, G, and B phosphors on its inner surface and an antireflection film, and a photocurable resin 13 on the panel. Safety glass 2 having an external anti-reflection film for improving explosion-proof characteristics and contrast, a rail 9 fixed by frit glass to the rear of the panel, and a fixed force applied to the rail And a shadow mask (8) which serves as the color selection of the electron beam, a funnel (4) bonded to the inner surface of the panel by frit glass, and having a neck portion (5) integrally formed at the rear, and encapsulated in the neck portion of the funnel. An electron gun 7 for emitting electron beams of three colors R, G, and B, and a deflection yoke provided to surround the outer circumferential surface of the neck portion and deflect the electron beam.

When the planar CRT configured as described above is supplied with power to the cathode of the electron gun to generate an electron beam, the generated R, G, and B electron beams are accelerated and focused while passing through the accelerating electrode and the focusing electrode of the electron gun, and by a deflection yoke. The image is reproduced by illuminating the phosphor by hitting each of R, G, and B tricolor phosphors applied to the inner surface of the panel accurately through the slots of the shadow mask in the horizontal or vertical deflection.

The structure of a conventional flat cathode ray tube panel is shown in Fig. 2A. That is, a safety glass 2 having an external anti-reflective coating film is disposed on the outer surface of the panel 3, the inner and outer surfaces of which are mirror-polished through polishing polishing, and R, G, B 3 having a predetermined size on the inner surface of the panel. A black matrix 16 is formed between the color phosphor 1 and the phosphor, and an aluminum film 14 is formed at regular intervals on the top of the phosphor.

The mirror surface treatment of the outer surface of the panel is to increase the efficiency of light generated by the phosphor when the phosphor formed on the inner surface of the panel is emitted by an electron beam collision. Has the effect of improving. In addition, the aluminum film is intended to prevent scattering of photons and electrons generated after the electron beam passing through the shadow mask collides with the phosphor.

In the conventional panel configured as described above, the primary reflection is made by external light on the outer surface of the panel, and the light that passes through the outer surface of the panel without the primary reflection is made secondary reflection on the inner surface of the panel, Finally, due to the transmission of light by the reflection of the inner surface of the panel when the phosphor is emitted, the third reflection is achieved when the screen is realized, and the density of light passing through the panel is increased due to the three reflections and transmissions.

Panel reflection amount = Panel 1st and 2nd reflection by external light + 3rd order reflection by phosphor

However, as the CRT becomes high-definition and high-quality and the TCO international standard is strengthened, it is difficult to satisfy the above regulation only by the conventional CRT structure, that is, the mirror surface inside and outside of the panel. Therefore, in order to solve the above problem, in addition to the safety glass coated with the anti-reflection coating, the anti-reflection film having a certain amount of thickness (a) is uniformly distributed on the entire surface inside the panel as shown in FIG. Satisfactory and clear image quality can be realized. The antireflection film is generally formed in a threaded or curved shape as shown in FIGS. 3A and 3B.

The average thickness of the anti-reflection film formed on the inner surface of the panel is called roughness and is expressed in angstroms or micrometers (µm). In general, when the inside and outside surfaces of the panel are mirror surfaces, the overall reflectance of the panel is about 4%, and when the anti-reflective coating is applied to the safety glass and the inner surface of the panel, the overall reflectance of the panel is reduced to about 0.4%. The relationship between the roughness and the surface reflectance of the panel is shown in Table 1 below.

TABLE 1

Roughness (㎛) 0 One 2 3 4 5 Surface reflectivity (%) 4 One 0.48 0.38 0.32 0.28

The process of manufacturing the panel having the above structure is as follows. Firstly, the molded panels undergo internal and external polishing. The inner and outer surfaces of the panel which have undergone the polishing process are mirrored, and in order to form an anti-reflection film on the inner surface of the panel, roughing and polishing are performed using Cerox instead of the polishing. The anti-reflective coating process has a uniform illuminance on the entire inner surface of the panel. Thus, it is possible to obtain a contrast enhancement effect by minimizing the light transmittance due to the secondary reflection where external light is reflected from the inner surface of the panel and the third reflection on the inner surface of the panel when the phosphor is emitted. Therefore, it is possible to provide a clear picture of high quality.

However, as the shape of the panel becomes flat, the deflection angle becomes larger toward the periphery of the screen, and mis-landing of the electron beam is likely to occur. In other words, when the electron beam scans the center of the screen, it is accurately landed in the slot of the shadow mask, so color separation is easy, but when scanning the periphery of the screen, the amount of deflection due to the flattening of the panel increases, so the scanning path of the electron beam becomes long. Difficult to separate accurate colors.

Therefore, in order to solve the problem of mis-landing in the periphery as described above, as shown in FIGS. 4 and 5A, the distance between the shadow mask slots, that is, the mask horizontal pitch, increases from the center of the screen toward the periphery. In addition, the pattern of the fluorescent screen on the inner surface of the panel (that is, the distance between the phosphor stripes) was formed to correspond to the mask horizontal pitch to improve the purity characteristics of the entire screen.

However, when the spacing between the phosphor stripes increases, the area of the black matrix film, which is a light absorbing material positioned between the phosphors, increases, resulting in a decrease in luminance toward the periphery of the screen, resulting in an unbalance in luminance and quality degradation. . Accordingly, in order to prevent the brightness of the peripheral part from decreasing, the slot size of the shadow mask and the slot size of the phosphor strip are different from each other as shown in FIG. 5B.

However, as the size of the shadow mask slot and the phosphor stripe in the periphery of the screen center increases, the size of the electron beam increases toward the periphery, and as the width of the phosphor increases, the focus performance that influences the screen characteristics decreases, and the phosphor As the width of the black matrix decreases due to the increase in width, there is a problem in that the landing margin decreases during electron beam deflection and the purity uniformity decreases, thereby degrading the quality of the screen.

Accordingly, the present invention is to solve the above problems, in particular, the flat panel for the tube to improve the luminance characteristics and purity characteristics of the screen formed by reducing the illuminance distribution of the inner surface anti-reflection film from the center portion of the panel toward the periphery It aims to provide.

1 is a structural diagram of a typical flat CRT,

2A shows reflection in a panel without an anti-reflection film;

2B shows reflection in a panel with an anti-reflection film;

3A is a view showing a curved antireflection film;

3B is a view showing a threaded antireflection film;

4 is a view showing a slot shape according to the position of the shadow mask,

Figure 5a is a view showing a horizontal pitch change of the slot according to the position of the shadow mask;

5b is a view showing the size of the slot and the phosphor width according to the position of the shadow mask;

6A is a diagram showing luminance according to illuminance of an anti-reflection film;

6B is a diagram showing surface reflectance according to roughness of an anti-reflection film;

6C is a diagram showing contrast according to roughness of an antireflection film;

7A is a diagram showing luminance, surface reflectivity, and contrast according to the roughness of the antireflection film;

7b is a view showing the change in illuminance according to the position of the panel;

8 is a view showing the roughness of the anti-reflection film according to the screen position of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

1: fluorescent film 2: safety glass 3: panel

14 aluminum film 15 antireflection film 16 black matrix

Technical means of the present invention for achieving the above object is to form a plurality of black matrix on the inner surface, the fluorescent surface coated with R, G, B phosphor between the black matrix and the black matrix, and the unevenness to prevent reflection on the inner surface A flat CRT panel comprising an antireflection film having a shape, characterized in that the antireflection film roughness distribution is different from the center portion and the peripheral portion of the panel.

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

The following three preconditions must be satisfied in forming an antireflection film that varies the illuminance of the present invention. First, luminance uniformity can be secured even if the shadow mask slot and the width of the phosphor of the center and the periphery of the screen are the same. Second, if the roughness of the panel's internal anti-reflection film is varied, it meets the surface reflectance standard (max 0.5%) of TCO international safety standard. Third, the contrast must be maintained when the roughness of the inner surface antireflection film is varied.

First, in terms of securing luminance uniformity, in a panel structure having a shadow mask slot and a phosphor width having a constant size, luminance variation according to inner surface roughness is shown in FIG. 6A. As shown, when the illuminance of the inner surface of the panel is 0 μm, that is, when it is mirrored, the luminance of about 39 fL may be secured. When the illuminance increases to 5 μm, the luminance increases to about 28 fL. Table 2 below shows the results of FIG. 6A.

TABLE 2

Roughness [㎛] 0 0.5 One 1.5 2 2.5 3 3.5 4 4.5 5 Luminance [fL] 39 38 36 34 32.2 31 30 29 28.5 28.2 28 ratio[%] 100 97 92 87 83 79 77 74 73 72 72

In general, when a shadow mask slot and a phosphor width having the same size are formed in the entire screen, the luminance of the peripheral portion is reduced by about 20% compared to the center portion of the screen. Therefore, it can be seen that in order to secure the uniformity of brightness in Table 2, the variable range of illuminance should not exceed a maximum of 2 μm. In addition, the use of clear glass as the material of the panel is effective for improving the brightness.

Next, look at the condition of the roughness to satisfy the surface reflectance standard (max 0.5%) of the TCO international safety standards, the surface reflectance (R) of the panel in the case of flat CRT is the outer reflectance (Er) of the safety glass Using the internal reflectance (Por) of the panel and the reflectance (Pir) of the outer surface of the panel is calculated in the following formula.

R = Er × Por × Pir

However, since the outer surface of the panel overlaps with the inner surface of the safety glass, it is not included in the reflectance calculation. Therefore, the formula for calculating the surface reflectance of a typical panel is as follows.

R = Er × Por

Safety glass for flat CRTs typically has a surface reflectance of about 0.5%. Therefore, in order to satisfy the surface reflectance standard (max 0.6%) among TCO international safety standards, the internal reflectance of the panel should be about 1% or less, and for this purpose, the inner surface of the panel should be at least 1.0 as shown in FIG. Roughness of 탆 or more should be secured. Table 3 below shows surface reflectance according to the roughness of FIG. 6B.

TABLE 3

Roughness [㎛] 0 0.5 One 1.5 2 2.5 3 3.5 4 4.5 5 reflectivity[%] 4 2 One 0.6 0.48 0.42 0.38 0.35 0.32 0.3 0.28

Finally, looking at the change in contrast, the contrast according to the illuminance is shown in Figure 6c and shown in Table 4. That is, when the illuminance of the inner surface of the panel is 0㎛, the contrast (CR) is 21, the contrast is maximum when the illuminance is 3㎛ and the contrast gradually decreases as the illuminance increases by 3㎛ or more. This means that the intensity of the screen decreases as the luminous efficiency of the phosphor formed on the inner surface of the panel decreases as the illuminance of the inner surface of the panel increases. Therefore, in order to secure the maximum contrast, the inner surface roughness of the panel should be maintained at about 3㎛.

TABLE 4

Roughness [㎛] 0 0.5 One 1.5 2 2.5 3 3.5 4 4.5 5 Contrast [CR] 21 22.5 24 25.3 26.1 26.6 27 27 26.8 26.2 25.5

Therefore, in sum of the three cases, in order to secure the brightness, surface reflectance and contrast of the screen, as shown in FIG. 7A, the roughness distribution of the antireflection film formed on the inner surface of the panel should satisfy the range of 1.0 μm to 2.5 μm.

The illuminance distribution on the inner surface of the panel is configured to gradually decrease from the center portion to the periphery portion as shown in FIG. 7B, and the decrease ratio of the illuminance is proportional to the increase rate of the black matrix. The equation for calculating the amount of roughness change of the inner surface of the panel is as follows.

Illuminance variation = Panel center illumination-4.1e ^-6 × X ^2.4

In the above formula, X represents the x coordinate according to the position of the screen.

When the center part roughness of the inner surface of the panel is 2.5 占 퐉, the illuminance gradually decreases according to the position X of the panel by the above equation, and the inner surface roughness of the panel at the outermost part of the panel becomes about 1.0 占 퐉. 8 shows the illuminance distribution of the inner surface radiation-proof film of the panel according to the present invention.

According to the present invention, the illuminance of the anti-reflection film formed on the inner surface of the panel forming the front body of the flat CRT gradually decreases from the center to the periphery of the screen, thereby ensuring uniform luminance of the entire screen and minimizing the inner surface reflectance of the panel. By securing a high contrast characteristic and making the shadow mask slot and the phosphor width of the periphery of the screen the same as the center portion, it is possible to prevent the deterioration of the purity uniformity due to the decrease in focus and the landing margin occurring in the conventional periphery.

Claims (8)

In a flat CRT panel comprising a plurality of black matrices formed on an inner surface, a fluorescent surface coated with phosphors of R, G, and B between the black matrix and the black matrix, and an antireflection film on the inner surface to prevent reflection. Roughness distribution of the anti-reflection film is present in the range of 1.0㎛ to 2.5㎛, The anti-reflection film roughness distribution in the center and periphery of the panel is reduced from the center to the periphery. The method of claim 1, The antireflection film roughness is a flat tube panel, characterized in that the screw thread or curved shape. delete The method of claim 1, The area of the black matrix increases from the center portion to the periphery portion, And a reduction ratio of the illuminance is proportional to an increase rate of the black matrix area. The method of claim 1, When the x-axis position coordinate of the panel is X, the amount of roughness change according to the position of the panel is Roughness variation = Panel center roughness-4.1e ^-6 × X ^2.4 Flat CRT panel characterized in that to satisfy. delete The method of claim 1, Roughness distribution of the anti-reflection film is 2.5 ㎛ in the center, Flat CRT panel, characterized in that 1.0㎛ in the outermost periphery. The method of claim 1, A panel for flat CRT tubes, characterized in that the material of the panel is clear glass.