KR19980081086A - Cathode ray tube - Google Patents

Abstract

The outer surface of the panel of the cathode ray tube is made flat and the inner surface is made convex toward the outer surface so that the image formed by the cathode ray tube is made flat on the user's eye and the clear image can be seen even on the effective surface end portion To be curved. And a thickness between the outer surface and the inner surface of the effective face diagonal end of the panel is B? T ₂ ? A where t ₂ is the thickness of the effective face diagonal end of the panel, and A is the transmittance ratio of the effective face end portion to the center is 85% , And B is the thickness of the panel at the effective face diagonal end when the inner radius of curvature (R _p ) is 8R). In addition, a cathode ray tube comprising a shadow mask satisfying considering the moldability of the shadow mask, 1.2R ≤ inner radius of curvature (R _p) ≤ 4R panel and, 1.2R ≤ radius of curvature (R _s) that satisfy ≤ 4R I suggest.

Description

Cathode ray tube

The present invention relates to a cathode-ray tube, and more particularly, to a cathode-ray tube panel that improves the phenomenon that a central portion of an image seen by a user is inserted into a screen as compared with a peripheral portion.

Generally, a cathode ray tube is a display device that implements an image by accelerating an electron beam emitted from an electron gun and selectively landing on a fluorescent screen through a shadow mask.

It is natural that the panel in which the image is formed in the cathode ray tube is formed with curved inner and outer surfaces, which corresponds to the high vacuum inside the cathode ray tube and facilitates the landing of the electron beam.

However, in consideration of the incident angle of general external light, the panel is severely affected by the external light reflection at the peripheral portion and the image formed at the peripheral portion is distorted by the user. Therefore, Is receiving the spotlight.

A panel in which the inner and outer surfaces are all formed flat is provided with a color masking means as a shadow mask which receives a tensile force to minimize deterioration of image quality due to the dome phenomenon of the shadow mask. Since the image formed on the fluorescent screen is refracted on the panel and then reflected on the user's eye, the image of the user does not look flat, but the center portion appears to be inwardly in comparison with the peripheral portion. This phenomenon becomes more and more intense in proportion to the size of the panel.

Various proposals for solving this problem have been published. Among the above proposals, Japanese Patent Application Laid-Open Nos. 6-44926 and 6-36710 disclose that a panel having a flat outer surface and a curved inner surface .

However, the panels disclosed in Japanese Patent Application Laid-Open Nos. 6-44926 and 6-36710 can adversely affect the image on the user's eyes due to excessive convexity. In addition, since the thickness of the peripheral portion is relatively thicker than that of the central portion, There is a problem that the luminance of the liquid crystal display device is lowered. Experiments have shown that this problem can be solved by molding the curvature of the inner surface of the panel within a certain range.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to make the image refracted on the panel flat on the user's eyes.

It is also an object of the present invention to optimize the thickness of the peripheral portion relatively thicker than the central portion of the panel, thereby minimizing deterioration in image quality due to the luminance difference between the central portion and the peripheral portion.

1 is a partial cross-sectional view of a cathode ray tube according to the present invention;

2 is a view showing a relationship between an inner surface of a panel and an image seen by a user according to the present invention;

3 is a partial cross-sectional view showing the radius of curvature of the inner surface of the panel according to the present invention.

4 is a graph showing the relationship between the state of the image seen by the user and the inner radius of curvature of the panel in the panel according to the present invention.

FIG. 5 is a graph showing the relationship between the transmittance ratio of the central portion and the inner radius of curvature in the panel according to the present invention. FIG.

6 is a cross-sectional view showing horizontal and vertical curvature radii of a shadow mask according to the present invention;

In order to attain the above object, the present invention proposes a cathode ray tube including a panel having an outer surface formed flat and an inner surface formed to be curved convexly toward the outer surface.

The inner surface of the panel is formed with an inner curvature radius R _p satisfying the following equation (1).

≤ 1.2R inner radius of curvature (R _p) ≤ 8R

Where 1R is the product of 1.767 and the effective face diagonal length of the panel.

The present invention also relates to a panel comprising a flat outer surface and an inner surface curved convexly toward the outer surface and having a thickness t ₂ between the outer surface and the inner surface at the effective surface diagonal end satisfying the following formula: A cathode ray tube having a cathode ray tube.

B≤ t ₂ ≤ A

In the above t ₂ is the thickness of the effective surface of the diagonal ends of the panel, A is the panel thickness in the case of the effective surface end portion transmittance ratio of 85% of the center contrast, the effective surface diagonal end, and B is the inner radius of curvature (R _p ) Is 8R, the panel thickness at the effective face diagonal end is shown.

The present invention also relates to an optical device comprising a flat outer surface and an inner surface curved convexly toward the outer surface, wherein the inner surface is formed with an inner curvature radius R _p satisfying the above-described formula (1) And a thickness t ₂ between the inner surface of the panel and the inner surface of the panel.

The present invention also relates to an image display apparatus including a panel coated with a phosphor on the inner surface thereof, a funnel sealed to the panel, a shadow mask suspended in an inner space of the panel to perform a color screening function, the panel is an outer home belonging to the electron gun, and is attached to the outer peripheral surface of the funnel to form the shadow mask, comprising: a deflection yoke for deflecting the electron beam with a radius of curvature (R _s) to satisfy the following equation (3), And the inner surface is formed with the inner radius of curvature (R _p ) satisfying the following equation (4).

1.2R ≤ radius of curvature (R _s) ≤ 4R

≤ 1.2R inner radius of curvature (R _p) ≤ 4R

In Equations (3) and (4), 1R is the product of 1.767 and the effective diagonal length of the panel.

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

1 is a schematic view showing a cathode ray tube according to the present invention. 1, the cathode ray tube includes a panel 1 coated with a phosphor on its inner surface, a funnel 3 sealed to the panel, a shadow mask 5 suspended in an inner space of the panel, And a deflection yoke 9 mounted on an outer circumferential surface of the funnel. The cathode ray tube constructed as described above implements an image by accelerating and deflecting the electron beam diverged and focused by the electron gun 7, then selecting it through the shadow mask 5 and landing on the fluorescent screen 15.

The outer surface 11 of the panel 1 is flattened, so that the reflection of the external light is minimized and the peripheral portion is clearly visible. Also, the inner surface 13 is formed into a curved surface curved convexly toward the outer surface 11. The reason why the inner surface 13 of the panel 1 is formed as a curved surface is that, in the case of a panel in which both the outer surface and the inner surface are both planar, the image formed on the fluorescent surface is seen as if the central portion of the user's eye is inward. And to make them look flat.

On the other hand, the shadow mask 5 is formed with a predetermined curvature by press working. The formed shadow mask 5 is easy to manufacture and can reduce the production cost as compared with a shadow mask (not shown) subjected to a tensile force applied to a conventional planar cathode ray tube.

2 is a view showing the relationship between the inner surface of the panel and the image reflected on the user's eyes. 2, the inner surface 13 of the panel 1 has an effective surface horizontal length h in a range where the user views the image 17 in order to make the flat image 17 visible to the user's eyes. As a standard, the following equation (5) must be satisfied.

y ₁ - y ₂ ≤ 0

Y ₁ is the vertical distance between the position where the image 17 implemented on the central axis c is visible and the outer surface 11 and y ₂ is the position where the image 17 is visible at the periphery of the effective surface, .

The effective surface refers to a virtual surface formed on the outer surface 11 of the panel 1, assuming that the fluorescent surface 15 is vertically projected onto the outer surface 11.

The reason why the user takes the effective horizontal length h as a reference for viewing the panel is that the viewing angle of the user and the flatness of the image can be appropriately determined at the distance.

FIG. 3 is a view showing a radius of curvature and a thickness of the inner surface of the panel. FIG. 3 shows that the thickness t ₁ (t ₂ ) of the panel 1 becomes thicker from the central portion toward the peripheral portion. Where t ₁ is the center thickness of the panel and t ₂ is the effective face diagonal thickness of the panel.

And reference character R _p denotes an inner radius of curvature (R _p ) of the panel.

1R for calculating the inner radius of curvature (R _p) of the panel (1) is defined as the following equation (6) of the.

1R = 1.767 x d

Where d represents the effective face diagonal length.

Therefore, d / 2 shown in the figure is the effective surface diagonal length d divided by half.

The definition of 1R is published by Matsushita, Japan in the paper of the SID Society in 1992 and has different values depending on the specifications of the panel.

4 shows the inner radius of curvature (R _p ) of the 17-inch panel which allows a flat image to be seen on the user's eye when the vertical axis is the value of y ₁ -y ₂ and the horizontal axis is the inner radius of curvature (R _p ) Of FIG. Referring to FIG. 4, it can be seen that Equation (5) is satisfied when the inner radius of curvature (R _p ) of the 17-inch panel is 8R or less. This inner radius of curvature (R _p) the 8R or less by image will have flatly appears to the user's eye, it is larger than 8R inner radius of curvature (R _p) in the center portion of the image visible in the eyes of the user into the inside than the periphery It means to be seen. This applies equally to panels of other specifications as well as 17-inch panels.

Therefore, the inner surface radius of curvature (R _p) of the panel 1 is provided in this embodiment should be not more than 8R.

The thickness of the panel 1 becomes gradually thicker from the center to the end of the effective surface. Since the transmittance ratio of the effective surface is larger than that of the central portion, it is possible to overcome the deterioration in image quality due to the luminance difference. To this end, in the present invention, a panel (1) having a transmittance ratio of about 85% The transmittance ratio is set to 85% or more in order to obtain an optimum effect in consideration of the panel weight, the production cost associated therewith, and productivity.

The panel 1 also uses a clear glass having a transmittance of 85% or more at the central portion in order to realize high brightness.

The method of obtaining the transmittance of a general clear glass panel 1 is defined by the following equation (7).

Transmittance (%) = (e -? ^T - 0.08) x 100

In the above,? Is 0.006090 and t represents the central thickness of the panel.

Figure 5 is a, the transmission ratio when the vertical axis to the center than the effective surface transmittance end portion ratio ((the transmittance of the effective surface end portion transmissivity / the central portion) × 100) to the inner surface of the horizontal radius of curvature (R _p) of about 85% Of the inner surface curvature radius (R _p ) of the 17-inch panel.

As shown in FIG. 5, in order to make the transmittance ratio of the effective surface end to the center to be 85% or more in the above, the inner radius of curvature R _p should be 1.2R or more. That is, since the transmittance ratio becomes 85% or more at an inner curvature radius (R _p ) of 1.2R or more, a good image quality can be realized because the luminance difference between the central portion and the effective surface end portion is small. On the other hand, since the transmittance ratio is lower than 85% at the inner radius of curvature R _p of less than 1.2R, the luminance difference of the effective surface end portion with respect to the central portion becomes large and the image quality deteriorates.

Therefore, Figure 4 and to Figure 5, an inner surface radius of curvature of the panel 1 is provided in the present embodiment (R _p) is satisfied the following equation (8) for.

≤ 1.2R inner radius of curvature (R _p) ≤ 8R

Where 1R is the product of 1.767 and the effective face diagonal length.

Therefore be in the range of the inner radius of curvature (R _p) the formula (8), it is possible to prevent the center portion of the image into visible symptoms to the user's eyes, it is possible to minimize the effective surface end portion luminance decreased.

The panel satisfying the above Equation (8) can be exemplified in the following Table 1.

C A B 15 inches 10.5 34.7 13.65 17 inches 11.5 35.7 15.10 19 inches 12.0 36.2 16.03 25 inches 13.0 37.2 18.22 29 inches 14.0 38.2 20.00 32 inches 15.0 39.2 21.74

Where C is the panel center thickness t ₁ , A is the panel thickness at the effective face diagonal end when the transmittance ratio of the effective face end is 85%, and B is the inner face curvature radius R _p is 8R , The panel thickness at the effective face diagonal end is shown. The unit of thickness and length in Table 1 is mm.

The transmittance and the inner radius of curvature R _p are inversely proportional to the thickness of the panel 1. Therefore, since the transmittance is larger than 85% and the inner radius of curvature (R _p ) must be smaller than 8R, the following equation (9) is established.

B≤ t ₂ ≤ A

The effective thickness of the surface diagonal end in the t ₂ is the panel (1), A is the case of the effective surface end portion transmittance ratio of 85% of the center contrast, the panel thickness of the effective surface of the diagonal end, and B is the inner radius of curvature (R _p ) is 8R, the panel thickness at the effective face diagonal end is shown.

When Equation (9) corresponds to the value of the 17-inch panel in Table 1, t ₂ is equal to or greater than 15.10, which is the panel thickness at the effective face diagonal end, when the inner radius of curvature R _p is 8R, Is less than or equal to 35.7, the panel thickness at the effective face diagonal end, when the transmittance ratio of the effective face end is 85%.

On the other hand, the range of the inner curvature radius R _p defined in Equation (8) should be further limited in consideration of the formability of the shadow mask 5. This is because the shadow mask 5 must have a radius of curvature R _{s that} is equal to or smaller than the radius of curvature R _p of the inner surface of the panel 1. In the present technology, the shadow mask 5 has a radius of curvature R _s ), the convexly formed surface does not have the strength to maintain the shape of the convexly formed surface, which causes the problem of being wrinkled or tumbled down to a completely different shape.

Therefore, the shadow mask 5 should have a radius of curvature R _s that satisfies the following formula 10 when considering the formability, and thus the radius of curvature R _p of the inner surface of the panel 1 is expressed by the following equation 11 .

1.2R ≤ radius of curvature (R _s) ≤ 4R

≤ 1.2R inner radius of curvature (R _p) ≤ 4R

In the above Equations 10 and 11, 1R is the product of 1.767 and the effective face diagonal length.

6 is a view showing the radius of curvature of the horizontal portion and the vertical portion of the shadow mask.

6, the radius of curvature R _H of the horizontal portion 5a of the shadow mask 5 is set so that the radius of curvature R _V ( _V ) of the vertical portion 5b is smaller than the radius of curvature R _{V of the} shadow mask 5, ) Is preferable. Therefore, the shadow mask 5 must satisfy the following expression (12).

R _H ≤ R _V

In the above, R _H is the horizontal curvature radius of the shadow mask 5, and R _V is the vertical curvature radius of the shadow mask 5.

On the other hand, when the inner radius of curvature (R _p ) of the panel is defined by Equation (11), B in Table 1 should be changed to B 'in Table 2 below.

15 inches 17 inches 19 inches 25 inches 29 inches 32 inches B ' 16.8 18.7 20.7 23.45 25.97 28.49

In the above, B 'represents the panel thickness (t ₂ ) at the effective face diagonal end when the inner radius of curvature (R _p ) is 4R.

Therefore, the above Equation (9) is limited to the following Equation (13).

B? T? ₂ ? A

Where t ₂ is the thickness of the effective diagonal end of the panel 1, A is the thickness of the panel at the effective diagonal end when the transmittance ratio of the effective surface end is 85%, and B ' And the panel thickness at the effective face diagonal end when the radius (R _p ) is 4R.

When Equation (13) corresponds to the value of the 17-inch panel, t ₂ is equal to or greater than 18.7, which is the panel thickness at the effective face diagonal end, when the inner radius of curvature (R _p ) is 4R, Is less than or equal to 35.7, which is the panel thickness at the effective face diagonal end, when the negative transmittance ratio is 85%.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

Since the cathode ray tube panel as described above has an inner curvature radius R _p equal to or larger than 1.2R and smaller than 8R, the image refracted on the panel can be made flat on the user's eyes, It is possible to minimize deterioration of image quality due to thickness difference.

Claims (16)

Wherein the outer surface is formed flat and the inner surface is formed to be curved convexly toward the outer surface. The cathode ray tube according to claim 1, wherein an inner surface of the panel is formed with an inner curvature radius (R _p ) satisfying the following expression (14). ≤ 1.2R inner radius of curvature (R _p) ≤ 8R Where 1R is the product of 1.767 and the effective face diagonal length. The cathode ray tube according to claim 1, wherein the inner surface of the panel is formed with an inner radius of curvature satisfying the following expression (15). ≤ 1.2R inner radius of curvature (R _p) ≤ 4R The cathode ray tube according to claim 1, wherein a transmittance of the central portion of the panel is 85% or more. The cathode ray tube according to claim 1, wherein the panel has a transmittance ratio of 85% or more with respect to the center of the effective surface. The cathode ray tube according to claim 5, wherein a transmittance of the central portion of the panel is 85% or more. The cathode ray tube according to claim 1, wherein the panel satisfies the following expression (16). y ₁ - y ₂ ≤ 0 y ₁ is the vertical distance between the position where the image implemented on the central axis is seen and the outer surface, and y ₂ is the vertical distance between the outer surface and the position where the image implemented at the periphery of the effective surface is seen. A flat outer surface; And a thickness between the outer surface and the inner surface at the effective surface diagonal end is formed to satisfy the following equation (17): " (17) " B≤ t ₂ ≤ A t ₂ is the thickness of the effective surface of the diagonal ends of the panel, A is the case of the effective surface end portion transmittance ratio of 85% of the center compared to the panel thickness of the effective surface of the diagonal end, and B is the inner radius of curvature (R _p) are 8R days In case, the panel thickness at the effective face diagonal end. The cathode ray tube according to claim 8, wherein a thickness between the outer surface and the inner surface at the effective surface diagonal end is formed to satisfy the following expression (18). B? T? ₂ ? A t ₂ is the thickness of the effective face diagonal end of the panel, A is the panel thickness at the effective face diagonal end when the transmittance ratio of the effective face end portion is 85%, and B 'is the inner face curvature radius (R _p ) is 4R , The panel thickness at the effective face diagonal end. A flat outer surface; And the inner surface is formed to have an inner curvature radius (R _p ) satisfying the following expression (19), and the thickness between the outer surface and the inner surface of the effective surface diagonal end is defined by the following equation Cathode ray tube having a panel formed to satisfy the expression (20). ≤ 1.2R inner radius of curvature (R _p) ≤ 8R 1R is the product of 1.767 and the effective face diagonal length. B≤ t ₂ ≤ A t ₂ is the thickness of the effective surface of the diagonal ends of the panel, A is the case of the effective surface end portion transmittance ratio of 85% of the center compared to the panel thickness of the effective surface of the diagonal end, and B is the inner radius of curvature (R _p) are 8R days In case, the panel thickness at the effective face diagonal end. A phosphor panel coated on the inner surface; A funnel sealed to the panel; A shadow mask suspended in an inner space of the panel to perform color screening; An electron gun mounted on a neck portion of the funnel to emit and concentrate an electron beam; And a deflection yoke mounted on an outer circumferential surface of the funnel to deflect the electron beam, wherein the outer surface of the panel is flat and the inner surface is formed of an inner curvature radius R _p satisfying the following expression (21) And a curvature radius (R _s ) satisfying the expression (22). ≤ 1.2R inner radius of curvature (R _p) ≤ 4R 1R is the product of 1.767 and the effective face diagonal length. 1.2R ≤ radius of curvature (R _s) ≤ 4R 1R is the product of 1.767 and the effective face diagonal length. 12. The cathode-ray tube according to claim 11, wherein a transmittance of the central portion of the panel is 85% or more. The cathode ray tube according to claim 11, wherein a transmittance ratio of the diagonal end of the panel to the effective surface is greater than 85%. The cathode ray tube according to claim 13, wherein a transmittance of the central portion of the panel is 85% or more. The cathode ray tube according to claim 11, wherein the panel satisfies the following expression (23). y ₁ -y ₂ ≤ 0 y ₁ is the vertical distance between the position where the image implemented on the central axis is seen and the outer surface, and y ₂ is the vertical distance between the outer surface and the position where the image implemented at the periphery of the effective surface is seen. The cathode ray tube according to claim 11, wherein the shadow mask satisfies the following expression (24). R _H ≤ R _V R _H is the horizontal curvature radius of the shadow mask 5, and R _V is the vertical curvature radius of the shadow mask 5.