JP2000285831A - Crt panel glass, its manufacture and crt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image with satisfactory contrast and uniform luminance by using a panel glass having a characteristic specified by applying a surface treatment film on the outer side surface of a base glass. SOLUTION: A light absorptive conductive reflection preventing film (surface treatment film) formed with a thickness distribution corrected so as to eliminate the transmittance difference between the center and periphery of a panel is applied to the outside surface of a base glass whose inner surface has a curvature radius only in the long axial direction. As the reflection preventing film, a titanium nitride film (light absorbing film), a silicon nitride film (oxidation barrier layer), and a silica film (low-refractive index film) are formed in order from the base glass side. When the minimum transmittance and maximum transmittance of the base glass are Tg (min) and Tg (max), and the maximum transmittance and minimum transmittance of the integrated matter containing the base glass and the surface treatment film are Tgf (max) and Tgf (min), respectively, the absolute value A of the ratio of [1-Tgf(min)/Tgf(max)] to [1-Tg (min)/Tg (max)] is set less than 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT having improved luminance uniformity and contrast and suppressing generation of double images.
Panel glass (hereinafter simply referred to as panel glass),
And a CRT having the panel glass and excellent in the above characteristics.

[0002]

2. Description of the Related Art A panel glass provided on a CRT is required to have a uniform brightness of an image displayed on the screen. As a method for displaying the image brightness uniformly, a method of keeping the transmittance of the panel glass constant in the plane, correcting the electron beam intensity distribution while maintaining the transmittance distribution in the panel glass, and A method of giving a distribution to the light emission intensity of the body can be used. However, in the latter method, the panel glass has a large transmittance distribution, for example, 1%.
When the transmittance distribution is 0% or more, there is a technical limit that cannot be met. On the other hand, as a conventional method of keeping the transmittance of panel glass constant, a method of eliminating the difference in transmittance due to the thickness of the glass by making the glass substrate transparent is performed. Cannot cope with recent flattening of panel glass having a large thickness difference, and it is difficult to make the transmittance of panel glass uniform. Further, it has been attempted to solve the above problem by increasing the transmittance of the glass substrate as an anti-reflection film-equipped panel glass and decreasing the transmittance of the anti-reflection film. There was a problem that occurred. As a result, in the case of the flat panel glass, there are problems that an image having uniform luminance cannot be seen, contrast is poor, and a double image occurs. Further, as another related technique, there is a method in which a glass front panel having a thickness deviation on the front surface of a panel glass is adhered to the panel surface with a resin to make the total glass thickness in the display surface constant. Japanese Patent Application Laid-Open No. 61-185852,
There has been a problem that the weight of the RT is increased and the cost of attaching the front panel is increased. In addition, in the projection type display, in order to improve the contrast, the projection screen is a colored screen having an external light absorbing property on its surface, and by continuously changing its coloring density from the center to the periphery, it is possible for an observer to observe the projection screen. Japanese Patent Laid-Open No. 6-3086 discloses a method for making the luminance distribution of a screen viewed uniform.
No. 14 discloses this. The publication also discloses that a similar effect can be obtained by giving a distribution to the thickness of the colored screen. These are considered to be effective as means for intentionally imparting a transmittance distribution to the display to make the luminance of the entire display surface uniform, but when applied to a CRT panel glass, a resin film equivalent to a colored screen is used. Alternatively, a front panel is required, and as in the above-described example, there has been a problem of an increase in weight and an increase in cost. Japanese Patent Application Laid-Open No. H10-177850 discloses a method of attaching a resin film to the front surface of a panel glass of a CRT, coloring the resin film, applying a colored coat on the surface of the resin film, and attaching the resin film to the panel glass. A method of making the transmittance of the central portion and the peripheral portion uniform by either coloring the pressure-sensitive adhesive is disclosed, but also has a problem of an increase in weight and cost.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image having uniform brightness even in a flat panel glass in which the difference in brightness between the central portion and the peripheral portion becomes remarkable particularly when colored glass is used. An object of the present invention is to provide a panel glass that can be seen with good contrast. Another object of the present invention is to provide a method for producing a panel glass, which can obtain the panel glass by a simple method at a low cost. Another object of the present invention is to provide a panel glass having electromagnetic wave shielding performance and a method for manufacturing the same. Another object of the present invention is to provide a panel glass having low reflection performance and a method for manufacturing the same. Another object of the present invention is to provide a panel glass in which occurrence of a double image is suppressed and a method for manufacturing the same. Another object of the present invention is to provide a CRT provided with a panel glass having the above excellent characteristics.

[0004]

According to the present invention, there are provided a panel glass of the following 1) to 22), a method of manufacturing the panel glass of 23), and a CRT of 24). Achieved. 1) A panel glass in which a surface treatment film is applied on an outer surface of the base glass, and the base glass is set so that an A value defined by the following formula (1) is less than 1 in an effective screen surface. Panel glass characterized in that a surface treatment film is applied on an outer side surface.

[0005]

(Equation 2)

In the above equation (1): Tg (min) and Tg (max)
Indicates the minimum transmittance (%) and the maximum transmittance (%) of the base glass itself. Tgf (max) and Tgf (min) indicate the maximum transmittance (%) and the minimum transmittance (%) of the integrated body including the base glass and the surface treatment film, respectively. 2) The panel glass according to 1), wherein the A value is 0.85 or less. 3) The panel glass according to 1) or 2), wherein the A value is 0.7 or less. 4) The difference between the minimum transmittance Tf (min) of the surface-treated film and the maximum transmittance Tf (max) of the surface-treated film is in the range of 2 to 20%. The panel glass according to the above. 5) The panel glass according to any one of 1) to 4), wherein the difference between Tf (min) and Tf (max) is in the range of 3 to 10%. 6) The panel glass according to any one of 1) to 5), wherein Tgf (min) / Tgf (max) is 0.8 or more. 7) The panel glass according to any one of 1) to 6), wherein Tgf (min) / Tgf (max) is 0.9 or more. 8) The panel glass according to any one of 1) to 7), wherein Tgf (min) / Tgf (max) is 0.95 or more. 9) The panel glass according to any one of 1) to 8), wherein the surface treatment film is an antireflection film for external light. 10) The panel glass according to any one of 1) to 9), wherein the surface treatment film is a light-absorbing film.

[0007] 11) At least one of the layers constituting the surface treatment film is a conductive film.
0) The panel glass according to any one of the above. 12) The panel glass according to any one of 1) to 11), wherein the change in the thickness of the base glass is mainly distributed in the long axis direction of the panel glass. 13) The panel glass according to any one of 1) to 12), wherein the change in the thickness of the base glass is mainly distributed in the short axis direction of the panel glass. 14) The panel glass according to any one of 1) to 13), wherein Tg (max) is in the range of 30 to 70%. 15) The panel glass according to any one of 1) to 14), wherein the reflectance as viewed from the inside of the base glass is 15% or less. 16) The surface treatment film is a film having a structure in which a light absorbing layer mainly containing titanium nitride and a layer mainly containing silica are formed on a base glass in this order. A panel glass according to any one of claims 15 to 15. (17) The panel glass as described in (16), wherein the light absorption layer containing titanium nitride as a main component has a film thickness distribution. (18) The panel glass according to (17), wherein the layer mainly composed of silica has a thickness distribution opposite to that of the light absorption layer mainly composed of titanium nitride. 19) The panel glass according to any one of 1) to 18), wherein Tgf (max) is in the range of 30 to 70%. 20) The transmittance Tf at any position on the surface treatment film is 4
1) to 19) characterized by being in the range of 0 to 90%.
Panel glass according to any one of the above. 21) The panel glass according to any one of 1) to 20), wherein Tf is in the range of 60 to 90%. 22) The panel glass according to any one of 1) to 21), wherein the outer diameter of the panel glass (the average radius of curvature of the outer surface of the face of the panel glass) is at least 5 times the R value calculated by the following equation (2). Panel glass as described. R value (unit: mm) = screen diagonal length (inch) × 42.5 + 45.0 Expression (2) (however, the screen diagonal length is an effective screen size (inch) of the display). A) a method for producing a panel glass, wherein a surface treatment film is provided on an outer surface of a base glass,
A method for manufacturing a panel glass, comprising applying a surface treatment film on an outer surface of a base glass such that an A value defined by the formula (1) is less than 1 in an effective screen surface. 24) A CRT having the panel glass according to any one of 1) to 22).

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The panel glass of the present invention has a surface treatment film formed on a substrate glass (hereinafter, also simply referred to as glass). The surface treatment film preferably has the following configuration, for example. (I) A structure in which a light absorbing film and a low refractive index film are formed in this order on a base glass. (Ii) A structure in which a light absorbing film, an oxidation barrier film, and a low refractive index film are formed in this order on glass on a substrate.

As the light absorbing film, it is preferable to use a material which substantially reduces the surface reflectance with respect to external light by the light interference effect with the low refractive index layer formed thereon. This results in excellent contrast of the image on the panel glass. Further, the light absorbing film is preferably conductive. By being conductive, it is preferable because the effect of preventing static electricity in the CRT and the leakage of electromagnetic waves from inside the CRT are prevented. Examples of the light absorbing film satisfying such characteristics include at least one metal selected from the group consisting of gold, copper, titanium, zirconium, and hafnium, and a film mainly containing a nitride of the metal. . Above all, those having a nitride of at least one metal selected from the group consisting of titanium, zirconium, and hafnium as a main component are preferable in view of the dispersion relationship between the refractive index and the extinction coefficient in the visible light region, and their optical constants Due to the light interference effect with the low refractive index film as the upper layer, the low reflection region in the visible light region (with respect to light from the film side (external light)) is widened. Further, a film mainly containing a nitride of at least one metal selected from the group consisting of titanium, zirconium, and hafnium is also preferable from the viewpoint of heat resistance, chemical resistance, and scratch resistance.

When two or more materials are used for the light absorbing film,
(1) It may be used as a composite material, or (2) it may be used by laminating films made of different materials so that the total film thickness (geometric film thickness, hereinafter the same) is preferably 5 to 25 nm. . Furthermore, the light absorbing film containing titanium nitride as a main component has an optical constant in the visible light region that matches well with the silica film to reduce the reflectance, and has an appropriate absorption coefficient value, and a moderate light absorption. The film thickness for obtaining the ratio is several n
Since it is in the range of m to several tens of nm, it is particularly preferable in terms of productivity and reproducibility.

The low refractive index film has a refractive index of 1.3.
Membranes that are between 5 and 1.7 are preferred. As the low refractive index film, a film containing silica as a main component (silica film) is preferable. The refractive index of the silica film is preferably from 1.46 to 1.52 (particularly preferably from 1.46 to 1.47), and the thickness of the silica film is preferably from 70 to 130 nm to reduce the low reflection wavelength range. This is preferable because it can be adjusted to the center of the visible light region. The silica film is preferably used also from the viewpoint of mechanical and chemical durability. The thickness of the silica film is more than 80 nm and 120 n
m or less is particularly preferable. Silica film thickness 80
If it is less than nm, the reflectance on the long wavelength side tends to increase, and if it exceeds 120 nm, the rise of the reflectance on the short wavelength side tends to shift to the long wavelength side.

After a light absorbing film is formed on a substrate glass, the light absorbing film is oxidized when a silica film as a low refractive index film is formed, or the light absorbing film is subjected to a post-heating treatment after the film formation. Desired characteristics may not be obtained because the absorbing film is oxidized. Therefore, between the light absorbing film and the silica film,
Inserting a layer that prevents oxidation of the light absorbing film (hereinafter referred to as an oxidation barrier layer) prevents oxidation during film formation,
Heat resistance can be improved. This kind of oxidation barrier layer is widely used in so-called Low-E glass using a silver film, and is described, for example, in US Pat. No. 4,546,691 and JP-A-59-16500.
No. 1 discloses that a barrier layer is formed for the purpose of preventing the silver film from being oxidized when an oxide film subsequently formed on the silver film is formed. As described above, this barrier layer is a thin film formed to prevent oxidation of another layer formed thereunder, and has no optical significance.

Various metal films and metal nitride films can be used as the oxidation barrier layer. The thickness is desirably 20 nm or less so as not to impair the original antireflection performance. If the thickness of the oxidation barrier layer is less than 1 nm, the improvement in heat resistance becomes insufficient. Therefore, 1
It is preferable to insert an oxide barrier layer having a thickness of 20 nm because heat resistance can be effectively improved.

As described above, the oxidation barrier layer has no optical significance and is an optically unnecessary layer.
The insertion of this layer may degrade the antireflection performance against external light. In particular, when the oxidation barrier layer is light-absorbing (for example, light-absorbing silicon), the thickness of the oxidation barrier layer is preferably about 5 nm or less from the viewpoint of antireflection performance. When a transparent oxidation barrier layer is used, the allowable thickness varies depending on the refractive index of this layer. When a material having a refractive index of about 2.0 (for example, silicon nitride or aluminum nitride) is used, the allowable film thickness becomes the largest, and a barrier layer of up to about 20 nm is formed between the lower light absorbing film and the upper silica film layer. In between, it can be inserted while maintaining low reflection characteristics against external light.

The oxidation barrier layer contains, as a main component, at least one metal selected from the group consisting of chromium, molybdenum, tungsten, vanadium, niobium, tantalum, zinc, nickel, palladium, platinum, aluminum, indium, tin and silicon. When a film or a film containing these nitrides as a main component, or a film containing at least one metal of the group consisting of titanium, zirconium and hafnium as a main component is used, sufficient antioxidant performance is improved and excellent. It is preferable because the maintenance of the anti-reflection characteristics can be compatible. In particular, a film containing silicon as a main component or a film containing silicon nitride as a main component is excellent in oxidation barrier performance, and when an upper silica film is formed by a sputtering method using a conductive Si target, the target is This is advantageous in terms of production because it is not necessary to increase the material.

As means for forming a surface treatment film (light absorbing film, low refractive index film or oxide barrier film) on the panel glass, a sputtering method, an ion plating method, a vacuum evaporation method, a CVD method, or the like is used. it can. Among them, a sputtering method and a vacuum evaporation method, which can easily increase the area and easily correct the film thickness distribution, are preferable. In particular, it is preferable to use an in-line type sputtering method in which good film quality and uniformity of the film quality are easily obtained and productivity is excellent. In addition, a DC (direct current) magnetron type sputtering method, in which the size of the apparatus can be easily increased, is preferable in terms of productivity. As a film forming technique of the surface treatment film, there is a film forming technique by a sol-gel method using ultrafine metal particles, but it is practically difficult to form a uniform film by this method. Further, a film formation method using ultrafine nitride particles requires a larger film thickness than a sputtering method, and cannot be said to be a preferable method in terms of cost, productivity, and performance. A nitride film (light absorbing film) formed by a sputtering method shows good heat resistance even in a thin film.

In the case where a film mainly composed of a metal nitride is used as the light absorption film, if a film mainly composed of a nitride is used as the oxidation barrier layer, the light absorption film and the oxidation barrier layer are formed in the same gas atmosphere. Can be formed by sputtering. This is a great advantage when an actual film forming facility by sputtering is assumed. That is, when a so-called in-line type sputtering apparatus excellent in mass productivity is considered, the light absorbing film and the oxidation barrier layer can be formed in the same chamber (referred to as chamber A). Therefore, the chamber for gas separation only needs to be provided between the chamber A and the chamber for forming a silica film which is subsequently formed on the upper layer, which is extremely efficient.

In particular, when a film containing titanium nitride as a main component is used as the light absorbing film and silicon nitride is used as the oxidation barrier layer, the effect of improving the adhesion between the titanium nitride film and the outermost silica film is also obtained. .

In the panel glass of the present invention, the A value defined by the above formula (1) is less than 1, preferably 0.85 or less, more preferably 0.7 or less, as a whole transmittance distribution in the effective screen plane. As such, a surface treatment film is provided on the glass. Here, the effective screen is based on the Japan Electronics and Machinery Industries Association standard EI.
It is determined in accordance with AJ ED-2136A (Effective dimensions and effective area of CRT glass bulb).
Tg indicates the transmittance of the base glass, and Tg (max) and Tg (min) indicate the maximum transmittance and the minimum transmittance of the base glass itself, respectively. Tgf (max) and Tgf (min) indicate the maximum transmittance and the minimum transmittance of the integrated body including the base glass and the surface treatment film, respectively. In other words, it indicates the maximum value and the minimum value of the total transmittance including the base glass and the surface treatment film. These are values within the effective screen surface of the panel glass.

The value A defined by the above equation (1) is a measure of the transmittance distribution of the panel glass (the difference in transmittance between the center and the periphery of the surface-treated panel and the center and the periphery of the base glass itself. Of the panel glass of the present invention, the smaller this value is, the more the coating has improved the transmittance distribution. In order to satisfy the above-mentioned value A, a surface treatment film having a transmittance distribution opposite to that of the base glass is formed. For example, when performing film formation by sputtering, a film thickness correction plate (also referred to as a mask or a jammer plate) for correcting the film thickness distribution of the surface treatment film.
Is formed, a film having a transmittance difference opposite to the transmittance difference between the center and the periphery of the base glass is formed. Since the correction of the film thickness distribution can be easily performed particularly in an in-line type sputtering apparatus, it is preferable to use the sputtering method also in this sense. In an in-line type sputtering apparatus, a mask (film thickness correction plate) for correcting the film thickness distribution may be provided in a direction perpendicular to the direction of travel of the base glass panel. Although it is not impossible to correct the film thickness distribution in the same manner by the vacuum evaporation method or the CVD method, the film quality of the light absorbing film may be non-uniform. In the sputtering method, the film thickness distribution on the long axis (or short axis) of the panel glass can be intentionally provided by this method, and the in-plane distribution of the total transmittance can be reduced. On the other hand, the film thickness distribution cannot be intentionally provided in the traveling direction of the panel glass by this method alone, but can be two-dimensionally provided by combining with other methods. For example, a method of obtaining a film thickness distribution in the front-rear direction by linking the traveling position of the panel glass and the power supplied to the target (in the traveling direction), fixing a mask having a shape similar to punching metal (or honeycomb) to the substrate carrier. A method of obtaining the film thickness distribution in the front-rear direction (in the traveling direction) by changing the aperture ratio between the front and rear may be considered. In the case of the above method, it is necessary to increase the distance between the mask and the substrate so that the mask shape is sufficiently blurred and reflected on the film thickness on the substrate. Alternatively, the substrate side mask may be provided with a two-dimensional distribution, and the film thickness distribution may be provided over the entire surface of the substrate only by this method. However, in the case of this method, it is difficult to provide a different thickness distribution for each layer of the multilayer film as described later. In order to apply a two-dimensional film thickness distribution to the surface treatment film on the panel glass, a mask for correcting the film thickness distribution in the width direction attached to the cathode side and a film thickness correction in the traveling direction attached to the substrate side ( punching metal)
A method of giving a film thickness distribution by using a combination with a mask is particularly preferable. The method of giving a two-dimensional film thickness distribution to the surface treatment film on the panel glass is particularly effective when the glass thickness of the panel glass has a two-dimensional distribution. In the case where the glass thickness of the panel glass has a one-dimensional distribution (for example, a cylindrical type panel glass, specifically, "Trinitron tube" manufactured by Sony Corporation), only the cathode-side mask described above is used. A one-dimensional film thickness distribution can be given to the surface treatment film. In this case, if a film thickness distribution is added to the film thickness in the major axis direction,
The film thickness in the minor axis direction is almost constant. FIG. 1 shows a front view of the panel glass. Fig. 2 (Example of panel glass with flat outer surface), where the short axis direction of the panel glass is used as the progressing method during film formation, and a one-dimensional film thickness distribution is applied to the surface treatment film only by the mask on the cathode side. As shown in the figure, while the film thickness distribution is provided in the major axis direction, the film thickness is substantially constant in the minor axis direction. In other words, the film thickness distribution becomes “kamaboko-shaped” (when Tg at the center> Tg at the end), and the film thickness distribution on the short side is almost the same as on the short axis. In the present invention, providing a film thickness distribution to the film thickness of the light absorbing film is effective in achieving the object of the present application. In that case, it is preferable that the film thickness distribution be “kamaboko type”. That is, when an electrode is provided in the peripheral portion (short side portion), the thickness of the light absorbing film (conductive film) in the peripheral portion (short side portion) is not thin, so that the low resistance necessary for shielding electromagnetic waves is required. Value can be maintained. It is preferable that the surface resistance of the film where the electrode is provided is 1 kΩ / □ or less. FIG. 3 (an example of a panel glass having a flat outer surface) shows a case of a “convex lens type” in which a film thickness distribution is provided over the entire surface. In the case of the “convex lens type” as shown in FIG. 3, the thickness of the light absorbing film (conductive film) in the peripheral portion becomes small, resulting in high resistance, which is not preferable from the viewpoint of electromagnetic wave shielding.

In order to further improve the uniformity of the total transmittance in the effective display screen while maintaining the anti-reflection effect,
The difference between the minimum transmittance Tf (min) of the surface-treated film and the maximum transmittance Tf (max) of the surface-treated film is preferably in the range of 2 to 20%, more preferably in the range of 3 to 10%. preferable. Note that the transmittance of the surface treatment film is the transmittance of the entire layer structure constituting the surface treatment film. Also, Tgf (mi
When n) / Tgf (max) is preferably 0.8 or more, more preferably 0.9 or more, the display luminance in the screen becomes uniform.

From the viewpoint of eliminating the occurrence of double images on the panel glass, Tg (max) is preferably 70% or less, particularly preferably 30 to 70%. When Tg (max) is less than 30%, it is necessary to increase Tf in order to make the total transmittance a practical value, and the conductive surface treatment film (particularly, the conductive light absorbing film) is thinned, It is not preferable from the viewpoint of conductivity. 70% conversely
In the case where the thickness is too large, it is necessary to increase the thickness of the light absorbing film, and the occurrence of a double image due to reflection from the glass / film interface (as viewed from the glass side) becomes a problem. A more preferable range is 35 to 65%, particularly 35 to 60%, for the same reason. In this case, Tgf is preferably set to 25 to 50% from the viewpoint of luminance and contrast.

In particular, when an antireflection film having a simple structure composed of a light absorption layer and (possibly an oxidation barrier layer) a low refractive index layer is used, Tf is set to 60 to 90% (particularly 60 to 85%). This makes it possible to set the total transmittance Tgf to an appropriate value, lower the inner surface reflectance, which will be described later, and eliminate double images and improve contrast.

The reflectance (internal reflectance) as viewed from the inside of the base glass is preferably 15% or less, which is useful for eliminating occurrence of double images. In particular, it is preferably set to 10% or less. This reflection is a total reflectance caused by the reflection from the interface between the surface treatment film and the base glass and the reflection from the interface between the base glass and the air on the front surface. In order to set the above-mentioned reflectance to the above range, a layer mainly composed of titanium nitride as a light absorption film as a surface treatment film, and a silicon oxide as a low refractive index film above the light absorption film as a main component Is preferably provided. Note that it is also preferable to provide an oxidation barrier layer between the light absorbing film and the low refractive index film. Also,
In this film configuration, it is preferable to provide a film thickness distribution to the low refractive index layer (and also to the oxidation barrier layer in some cases) in order to maintain optical characteristics, in particular, low reflection performance against external light in the visible region. The refractive index layer desirably has a thickness distribution opposite to that of the light absorption layer. This is because an increase in the thickness of the upper layer has the effect of restoring the shift of the spectral reflection spectrum to the shorter wavelength side due to the thinner light absorbing film in the peripheral portion. As described above, providing the lower layer and the upper layer with the opposite film thickness distribution can be easily achieved by the in-line type sputtering method. That is, a mask for giving a unique film thickness distribution may be provided in the film formation space of each target. Providing the upper layer with a thickness distribution opposite to that of the lower layer (light absorbing film) is effective for making the reflection color tone uniform in the plane and the transmittance distribution in the plane. The tank containing titanium nitride as a main component as the light absorbing film preferably contains oxygen, and this layer is formed of TiN _x O _y.
In the formula, x in TiN _x O _y is a number of 0.5 to 1.5, preferably 0.8 to 1.1, y is 0 to 0.5,
Preferably it is a number of 0.03 to 0.4.

Further, Tgf (max) is preferably in the range of 30 to 70%, particularly 35 to 65%. The transmittance Tf at an arbitrary position of the surface treatment film is preferably in the range of 40 to 90%, particularly preferably 60 to 90%. Where Tf
Is a value defined by Tgf / Tg. In the antireflection film having the above-mentioned configuration (i) or (ii), the inner surface reflectance is 1
In order to reduce the thickness to 5% or less, the thickness of the light absorbing film of the first layer is set to 3%.
It is necessary to be not more than 00 ° (since the reflection at the glass / antireflection film interface increases as the film thickness increases). On the other hand, in order to keep the surface resistance value at 1 kΩ / □ or less while maintaining the low reflection characteristics on the film surface side, the thickness of the first layer light absorbing film needs to be 50 ° or more. % Or less. Tf is particularly preferably 60 to 85%.

The panel glass of the present invention has a panel outer diameter of:
It is suitably used as a flat panel glass having an R value that is at least five times the R value calculated by equation (2). R value (unit: mm) = screen diagonal length (inch) × 42.5 + 45.0 (2) Even if the panel glass of the present invention is a flat panel glass, as described above, The range of the value A in the above equation (1), the difference between the minimum transmittance Tf (min) and the maximum transmittance Tf (max) of the surface-treated film, the ratio of Tgf (min) / Tgf (max), Tg
Since the range of the value of (max), the range of the Tgf (max) value, and the like are specified, the transmittance of the panel glass is corrected, and the uniformity of the transmittance is achieved.

The panel glass of the present invention can be produced by providing each layer on a base glass by a method known per se. For example, by a sputtering method, a vacuum evaporation method, a CVD method, a sol-gel method, etc. described in paragraphs [0059] of JP-A-9-156964, a light absorbing film, a protective film, an antioxidant film, A panel glass can be manufactured by forming an intermediate film or the like.

The panel glass of the present invention can be applied to a CRT, and the CRT provided with the panel glass of the present invention
An image with uniform brightness is seen with good contrast, and a double image does not substantially occur.

[0029]

EXAMPLES The present invention will be described below in detail with reference to examples, but the scope of the present invention is not limited by the examples. In the following examples, the transmittance was measured by the following method. Tg and Tgf are measured by a transmittance meter corrected so that the transmittance by air becomes 100%, and Tf is Tf.
It was obtained as a measured value based on the calculation of gf / Tg.

Example 1 (Manufacture of panel glass) In cylindrical form, EIA
Glass base of glass code H5702 specified by J
(Tint base glass) base glass (long axis direction)
Panel glass whose inner surface has a curvature only in the
48% transparency at the center and 40% at the periphery in the glass major axis direction.
Designed to be excessive. (Conventionally, this central and peripheral
It is impossible to make the transmittance difference 8% uniform in a circuit.
Was. Note that the substrate glass of Example 1 has a 19-inch
Panel was used. Panel glass outer diameter is 4300mm
Met. In this case, R = 850. Spattery
Method eliminates the difference in transmittance between the center and the periphery of the panel.
To correct the film thickness distribution of the light absorbing conductive anti-reflective coating
The film was formed. The anti-reflection film is nitrided from the base glass side.
Titanium nitride film (light absorbing film), silicon nitride film (oxidation barrier
Layer) and silica film (low refractive index film)
is there. To correct the film thickness distribution, a film thickness correction plate (jam plate) is installed.
And install the panel with the long axis direction of the panel as the vertical direction.
It was done by doing. Each film thickness was 14.0 at the center.
nm (titanium nitride film), 5.0 nm (silicon nitride film),
95.0 nm (silica film), and 9.5 n
m (titanium nitride film), 4.0 nm (silicon nitride film), 1
It was 15.0 nm (silica film). The actual film formation is as follows
I went. Using an in-line type sputtering device,
Metallic titanium target for titanium nitride film formation in an empty tank
And a boron-doped silicon target for forming a silicon nitride film.
Get set up. In the second vacuum chamber, a silica film is formed.
A boron-doped silicon target was set. Washed
Substrate glass (panel glass) in the chamber
The direction is up and down (perpendicular to the direction of travel)
After installation, the total back pressure is 2 × 10^-3Vacuum down to Pa
Was. The thickness correction plate is placed on the target (cathode).
Of the panel glass correspond to both sides in the long axis direction
Mounted in position. Next, a discharge gas is placed in the first vacuum chamber.
And a mixed gas of argon and nitrogen (nitrogen is 20% by volume)
And a discharge pressure of 4 × 10^-1Conductor to Pa
Was set. Then, a negative direct current was applied to the titanium target.
Voltage (power density is about 4.0 W / cm ^Two)
A titanium oxide film was formed. Continue, in the same atmosphere, Silico
Module to the target (pulse-like waveform
Voltage to the module through a negative DC voltage (power density)
The degree is about 1.5W / cm^Two) To form a silicon nitride film.
Filmed. ESCA conducted on the formed titanium nitride film
When the film composition was analyzed, Ti: N: O (atomic ratio) was
1.0: 0.95: 0.05. Next, the substrate is
Argon is transferred to a vacuum chamber and then evacuated to a high vacuum.
And a mixed gas of oxygen (about 30% by volume of oxygen)
× 10^-1The conductance was set to Pa.
Next, an AC power supply is applied to the silicon target (power
Density is about 6.0 W / cm^Two) To form a silica film (refractive index n =
1.47). Fig. 2 shows the thickness distribution of the titanium nitride film.
It became like. As a result, the total transmittance Tgf is
A panel glass of the present invention, which was substantially uniform around the periphery, was produced.
The A value was 0.52. Difference between Tf (min) and Tf (max)
Is 9%, and Tgf (min) / Tgf (max) is 0.90.
Was. For comparison, a uniform film thickness was obtained without correcting the film distribution.
A panel glass was prepared in the same manner as described above except that the film was formed. A
The value was 1. The difference between Tf (min) and Tf (max) is 0%
And Tgf (min) / Tgf (max) was 0.81. Book
The in-plane reflectance distribution of the inventive panel glass is
Origin (center), and x
= ± 210 (mm), four points of y = ± 150 (mm)
Was measured at five points. 4 at any point
Average resistance from the film side in the wavelength range of 50 nm to 650 nm
Emissivity is less than 0.5% and color tone is specified by CIE.
X = 0.15 to 0.30, y = 0.15 in xy coordinates
０．３0.35, which was a good result. next,
Wavelength 550nm from glass side (opposite side of film side)
Reflectance (internal reflectance) was measured. The internal reflectance is
The central part is 12% and the peripheral part is 8%.
there were. The measurement of the internal reflectance was performed simply. Sand
That is, a panel having a uniform thickness of 2 mm and a size used in Example 1
Using a float glass substrate similar to glass,
The same table as in Example 1 under the same film forming conditions as in Example 1 on one side of the glass substrate.
After forming the surface treatment film, the glass surface side of the glass substrate (film
From the center) and the peripheral part
And the numerical value was defined as the internal reflectance. Also, the surface resistance value
Is 200Ω / □ at the center of the panel and at the periphery
It was 350 Ω / □. This is a titanium nitride film near the periphery
Is thin. Evaluation of resistance value as CRT
Is the electrode on the long side of the panel glass or the electrode on the short side
It is performed with the resistance value between. In the case of the present embodiment, an electrode is
When installed, the resistance value is about 1700Ω, which is
It is the limit of conductivity that can be accepted. However, the electrode on the short side
When installed, the resistance is about 500Ω, very good
There was no practical problem. Thus nitriding only in the long axis direction
Providing a titanium film thickness distribution is important for ensuring conductivity.
Very advantageous. (Evaluation on transmittance of panel glass) Obtained panel
T at the center, middle, and periphery in the long axis direction of glass
g, Tf and Tgf were measured. The results are shown in Table 1 (comparison) and Table 2.
(The present invention).

[0031]

[Table 1]

[0032]

[Table 2]

The following is clear from the results shown in Tables 1 and 2. The transmittance distribution of the glass substrate has a difference of about 10% between the central portion and the peripheral portion in the long axis direction in the effective plane. When a uniform film is formed by a conventional method, this transmittance distribution is reproduced as it is as a total transmittance distribution on the panel glass, and the difference in luminance between the central portion and the peripheral portion cannot be eliminated. On the other hand, by controlling the film thickness distribution according to the present invention, the transmittance distribution in the central portion and the peripheral portion is suppressed to approximately 4% or less, and uniform brightness can be exhibited. In this example, Tg is higher at the center than at the periphery.

Example 2 This example is an example of producing and evaluating a panel glass using a tint base glass as a base material and exhibiting a transmittance distribution different from that of Example 1. (Manufacture of panel glass)
A panel glass of the present invention is produced in the same manner as in Example 1, using a base glass having a predetermined transmittance difference in the minor axis direction. However, in this example, the panel glass is installed so that the short axis direction is the vertical direction (perpendicular to the traveling direction). The A value is 0.00 (exactly 0.00022). The difference between Tf (min) and Tf (max) is 8.29%,
gf (min) / Tgf (max) is 1.00. As a comparison,
A panel glass is produced in the same manner as described above, except that the film is formed with a uniform film thickness without correcting the film distribution. The A value is 1. T
The difference between f (min) and Tf (max) is 0%, and Tgf (min) / Tg
gf (max) is 0.89. (Evaluation of Panel Glass) Tg, Tf, and Tgf at the center, middle, and peripheral portions in the minor axis direction of the obtained panel glass are measured. The results are shown in Table 3 (comparison) and Table 4 (present invention).

[0035]

[Table 3]

[0036]

[Table 4]

From the results shown in Tables 3 and 4, the same conclusion as in Example 1 can be concluded. In this example, the peripheral portion has a higher Tg than the central portion.

Example 3 This example is an example in which a tint base glass having a transmittance distribution in both the major axis and the minor axis is used as a base material. (Manufacture of panel glass)
A panel glass of the present invention is produced in the same manner as in Example 1 using a base glass having a predetermined transmittance difference in the major axis and minor axis directions. However, in this example, the mask for correcting the film thickness distribution in the width direction attached to the cathode side and the mask for correcting the film thickness distribution in the traveling direction (punched metal) attached to the substrate side are used in combination, so that the A two-dimensional film thickness distribution is applied to the light absorbing film (titanium nitride film). The A value was 0.65. The difference between Tf (min) and Tf (max) is 10.76%, and Tgf (min) / Tgf (max) is 0.82. For comparison, a panel glass is produced in the same manner as described above, except that the film is formed with a uniform film thickness without correcting the film distribution. The A value is 1. The difference between Tf (min) and Tf (max) is 0%, and Tgf (min) / Tgf (max) is 0.72. (Evaluation of panel glass) T at the central part, middle part, and peripheral part in the major axis direction and the minor axis direction of the obtained panel glass
g, Tf and Tgf are measured. The results are shown in Tables 5 to 7 (comparison) and Tables 8 to 10 (present invention). Note that the column direction of the table is the long axis direction, the horizontal column direction is the short axis direction, and so on. For example, in Table 5, the value of the central part in the major axis direction and the intermediate part in the minor axis direction are 46.85. As can be seen from Table 7, the "comparative" panel glass has a maximum transmittance difference of about 11% between the central part and the peripheral part, and cannot be used as a CRT. On the other hand, as can be seen from Table 10, the in-plane distribution of the panel glass of the present invention is improved up to 7% at the maximum, and uniform brightness can be exhibited.

[0039]

[Table 5]

[0040]

[Table 6]

[0041]

[Table 7]

[0042]

[Table 8]

[0043]

[Table 9]

[0044]

[Table 10]

From the results shown in Tables 5 to 10, it is clear that the panel glass of the present invention shows more uniform transmittance.

Example 4 This is an example using a semi-clear base glass having the same shape as that of Example 1. (Production of panel glass) A panel glass of the present invention was produced in the same manner as in Example 1 except that a base glass made of semi-clear base glass was used. The A value was 0.24. T
The difference between f (min) and Tf (max) is 3%, and Tgf (min) / T
gf (max) was 0.98. For comparison, a panel glass was produced in the same manner as above except that the film thickness was not corrected and the film was formed to have a uniform film thickness. The A value was 1. Tf (min)
And the difference between Tf (max) and Tf (max) is 0%, and Tgf (min) / Tgf (ma
x) was 0.93. (Evaluation of Panel Glass) Tg, Tf, and Tgf were measured at the central portion, the intermediate portion, and the peripheral portion in the major axis direction of the obtained panel glass. The results are shown in Table 11 (comparison) and Table 12 (present invention).
It was shown to.

[0047]

[Table 11]

[0048]

[Table 12]

From the results shown in Tables 11 and 12, it is clear that the panel glass of the present invention shows more uniform transmittance.

Example 5 When an image was taken on an actual CRT using the “comparative” panel glass produced in Example 1, an image with uniform brightness could not be obtained. On the other hand, when the reflectance of the panel glass of the present invention produced in Example 1 from the glass surface was measured, it was 7%.
When an image was taken on an actual CRT, an image with uniform luminance was seen with good contrast, and a double image was suppressed. CAD that requires high-definition images
・ Reading was possible even for CAM applications.

[0051]

According to the panel glass of the present invention, even with a flat panel glass, an image with uniform luminance can be seen with good contrast. According to the present invention, it is also possible to provide a panel glass having an electromagnetic wave shielding performance and a low reflection performance. Further, it is possible to provide a panel glass in which generation of a double image is suppressed. Further, according to the present invention, it is possible to obtain a panel glass having the above-mentioned various characteristics by a simple method at a low cost. In addition, since the CRT of the present invention is provided with the panel glass having the above-described excellent characteristics, an image having a uniform luminance can be similarly viewed with good contrast. Also,
A CRT that also has electromagnetic wave shielding performance and low reflection performance can be obtained. Further, a CRT in which the occurrence of double images is suppressed can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a panel glass.

FIG. 2 is a cross-sectional view of a panel glass with a surface treatment film when there is a difference in glass thickness only in a long axis direction.

FIG. 3 is a cross-sectional view of a panel glass with a surface treatment film when there is a difference in glass thickness in both short axis and long axis directions.

Claims (14)

[Claims] 1. A CRT panel glass having a surface treatment film formed on an outer surface of a substrate glass, wherein an A value defined by the following equation (1) is less than 1 in an effective screen surface. A CRT panel glass for a CRT, wherein a surface treatment film is provided on an outer surface of the base glass. (Equation 1) In the above formula (1): Tg (min) and Tg (max) are the minimum transmittance (%) and the maximum transmittance (%) of the base glass itself, respectively.
Is shown. Tgf (max) and Tgf (min) indicate the maximum transmittance (%) and the minimum transmittance (%) of the integrated body including the base glass and the surface treatment film, respectively. 2. The method according to claim 1, wherein the difference between the minimum transmittance Tf (min) of the surface-treated film and the maximum transmittance Tf (max) of the surface-treated film is in the range of 2 to 20%. CRT panel glass. 3. The CRT according to claim 1, wherein Tgf (min) / Tgf (max) is 0.8 or more.
For panel glass. 4. The CRT panel glass according to claim 1, wherein the surface treatment film is an antireflection film for external light. 5. The CRT panel glass according to claim 1, wherein Tg (max) is in the range of 30 to 70%. 6. A reflectance of 15% as viewed from the inside of the base glass.
The CRT panel glass according to any one of claims 1 to 5, wherein: 7. The surface treatment film is characterized in that a light absorption layer containing titanium nitride as a main component and a layer containing silica as a main component are formed on a base glass in this order. The CRT panel glass according to any one of claims 1 to 6. 8. The C according to claim 7, wherein the light absorbing layer mainly composed of titanium nitride has a film thickness distribution.
RT panel glass. 9. The CRT panel glass according to claim 8, wherein the layer mainly composed of silica has a thickness distribution opposite to that of the light absorption layer mainly composed of titanium nitride. . 10. The CR according to claim 1, wherein Tgf (max) is in the range of 30 to 70%.
Panel glass for T. 11. The CRT panel glass according to claim 1, wherein a transmittance Tf at an arbitrary position of the surface treatment film is in a range of 40 to 90%. 12. The CRT panel glass according to claim 1, wherein the outer diameter of the CRT panel glass is at least 5 times the R value calculated by the following equation (2). . R value (unit: mm) = screen diagonal length (inch) × 42.5 + 45.0 (2) 13. A method of manufacturing a panel glass for a CRT, wherein a surface treatment film is provided on an outer surface of a base glass, wherein an A value defined by the formula (1) in an effective screen plane. A method for producing a CRT panel glass, comprising applying a surface treatment film on an outer surface of a base glass so that the value of the glass is less than 1. 14. The CR according to claim 1, wherein
CRT with panel glass for T.