JPH0992168A - Color image receiving tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of brightness, mixed color, or white uniformity of a color image receiving tube provided with its fluorescent substrate surface having a phosphor layer with a color filter. SOLUTION: A color image receiving tube is provided with phosphor surface 3 having three-color phosphor layers 12B, 12G, and 12R for emitting blue, green, and red on the inner surface of a panel 1 and is composed of a phosphor layer having a filter for which at least the blue phosphor layer 12B of these three- color phosphor layers selectively absorbs the light in a specific wave length area to an external light. For each phosphor constituting its three-color phosphor layer, the average particulate diameter for the blue phosphor is 6.4±0.3μm, and the average particulate diameter for the green and red phosphors is 5.5±0.5μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube, and more particularly to a color picture tube in which a phosphor layer constituting a phosphor screen is composed of a filter substance-coated phosphor which selectively absorbs light in a specific wavelength region. .

[0002]

2. Description of the Related Art Generally, a color picture tube has an envelope composed of a panel and a funnel, and the inner surface of the panel is
A phosphor screen made of a three-color phosphor layer that emits blue, green, and red is provided, and a shadow mask is arranged inside the phosphor screen so as to face the phosphor screen. On the other hand, an electron gun that emits three electron beams is arranged in the neck of the funnel. Then, the three electron beams emitted from this electron gun are deflected by the horizontal and vertical deflection magnetic fields generated by the deflection device mounted outside the funnel, and the fluorescent screen is horizontally and vertically scanned to form a color image. It is formed in a display structure. Among such color picture tubes, at present, in particular, an in-line type color in which the three-color phosphor layer of the phosphor screen is formed into a stripe shape and the electron gun is an electron gun that emits three electron beams arranged in a row passing through the same plane. The picture tube is the mainstream.

In such a color picture tube, it is known to provide a color filter corresponding to the three-color phosphor layer in order to improve the contrast under bright external light. That is, the emission color of each phosphor is selectively transmitted to each of the three-color phosphor layers without attenuation as much as possible,
In addition, it is known to provide a filter that selectively absorbs light other than the emission color of the phosphor with respect to external light incident on the phosphor screen. By providing such a filter, reflection of external light on the fluorescent screen can be significantly reduced without impairing the light emission of each fluorescent substance, and the contrast of an image drawn on the fluorescent screen can be improved.

As a method of forming such a color filter, Japanese Unexamined Patent Publication No. 50-56146 discloses that three-color phosphors are coated with fine particles of a filter substance corresponding to each emission color, and this filter substance-coated phosphor is used. Using,
A method of forming a filter is shown. As the filter substance, cobalt aluminate or ultramarine blue is used for the blue phosphor, chrome green or cobalt green is used for the green phosphor, and pigments such as red iron oxide and molybdenum orange are used for the red phosphor.

In general, a phosphor having an average particle size of about 7.0 μm is used for the three-color phosphor layer of the phosphor screen of the color picture tube in view of the brightness and the quality of the phosphor screen. In terms of cost, it is better to form the three-color phosphor layer with a phosphor having a small average particle size. This is because the optimum coating amount of the phosphor increases with the particle size from the relationship between the particle size, the coating amount, and the brightness. Therefore, if the particle size of the phosphor is selected within a range where the brightness and the quality of the phosphor screen are not practically problematic, a phosphor screen having excellent cost performance can be formed.

On the other hand, the color filter provided for improving the contrast under bright outside light is such that the blue filter substance is about 1 to 5% in weight ratio with the phosphor particles, and the red filter substance is red. About phosphor, 0.1
About 0.2% of red filter material is used.

[0007]

As described above, in general, the three-color phosphor layer forming the phosphor screen of the color picture tube has a mean particle size of about 7 μm due to the relationship between the brightness and the quality of the phosphor screen. The body is used. On the other hand, in order to improve the contrast under bright outside light, it is known to provide a color filter corresponding to the three-color phosphor layer. For the blue phosphor, about 1 to 5% by weight of the blue filter substance is used. However, for red phosphors, about 0.1 to 0.2% by weight of red filter material is used.

However, when the color filter is provided as described above, the amount of the blue filter substance used is large, especially for the blue phosphor, so that there is a problem in that the brightness is lowered. That is, as shown in Table 1 for the phosphors having the average particle diameters of 7.0 μm and 5.5 μm, when the amount of the filter substance is the same, the external light reflectance deteriorates from 100 to 115 in relative value, and When the amount of the filter material is adjusted so that the external light reflectance is about the same, the brightness is reduced from 100 to 90.

[0009]

[Table 1]

Further, when forming a phosphor screen, if three-color phosphor layers are formed in the order of blue, green, and red, if the particle size of the blue phosphor is larger than that of the green and red phosphors, the blue phosphor layer is formed. The green phosphor applied after the formation remains as a residue in the blue phosphor layer, causing so-called color mixing, which deteriorates the color purity and white uniformity.

As a countermeasure against this color mixing, the amount of polyvinyl alcohol (PVA) in the photosensitive blue phosphor slurry which is usually applied when forming the blue phosphor layer is reduced to reduce the viscosity. When the viscosity of the photosensitive fluorescent substance slurry is reduced by decreasing the amount, the bubbles are likely to be generated at the time of applying the slurry, and as shown in Table 2, the occurrence rate of the bubble defect in the slurry applying step is increased.

[0012]

[Table 2]

The present invention has been made to solve the above-mentioned problems, and it is possible to reduce luminance deterioration, color purity and white uniformity in a color picture tube having a phosphor screen composed of a phosphor layer having a color filter. The purpose is to prevent deterioration.

[0014]

[Means for solving the problems] Blue, green,
A phosphor screen having a three-color phosphor layer that emits red light is provided,
In the color picture tube including at least the blue phosphor layer of the three-color phosphor layer having a filter that selectively absorbs light in a specific wavelength region with respect to external light, the three-color phosphor layer is formed. The phosphors of the respective colors were phosphors having an average particle size of 6.4 ± 0.3 μm for the blue phosphor and phosphors having an average particle size of 5.5 ± 0.5 μm for the green and red phosphors.

Here, the filter that selectively absorbs light in a specific wavelength region with respect to external light means that light other than the emission color of the phosphor is selectively absorbed with respect to external light incident on the phosphor screen. As the filter substance, cobalt aluminate or ultramarine blue is used for the blue phosphor, chrome green or cobalt green is used for the green phosphor, and pigments such as red iron oxide and molybdenum orange are used for the red phosphor.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a color picture tube which is one of the forms. This color picture tube has an envelope composed of a panel 1 and a funnel-shaped funnel 2, a striped fluorescent screen 3 described later is provided on the inner surface of the panel 1, and the fluorescent screen 3 faces the fluorescent screen 3. The shadow mask 4 is arranged inside. On the other hand, in the neck 5 of the funnel 2, an electron gun 7 for emitting the three electron hems 6B, 6G, 6R arranged in a line passing on the same horizontal plane is arranged. Then, the three electron hemes 6B, 6G, and 6R emitted from the electron gun 7 are deflected by the magnetic field generated by the deflecting device 9 mounted outside the funnel 2, and the phosphor screen 3 is horizontally and vertically scanned. , A structure for displaying a color image.

As shown in FIG. 2, the phosphor screen 3 is embedded in a vertically elongated striped light absorbing layer 11 arranged in parallel at a predetermined interval in the horizontal direction and a gap portion of the light absorbing layer 11. Provided in the blue, green, and red light emitting strips 12B, 12G in the form of vertically elongated stripes
It consists of 12R. The three-color phosphor layers 12B, 12G,
Of the 12R, at least the blue phosphor layer 12B is provided with a filter that selectively transmits the emission color of the blue phosphor forming the blue phosphor layer 12B and selectively absorbs incident external light. Has become. This filter uses a pigment such as cobalt aluminate or ultramarine blue for the blue phosphor layer 12B, a pigment such as chrome green, cobalt green, or TiCoAlLi for the green phosphor layer 12G.
The red phosphor layer 12R is composed of a pigment (filter substance) such as bean paste or molybdenum orange.

In particular, in the color picture tube of this example, the blue phosphor layer 12B is composed of a blue phosphor having an average particle size of 6.4 ± 0.3 μm, and the green and red phosphor layers 12G,
12R is composed of green and red phosphors each having an average particle diameter of 5.5 ± 0.5 μm.

Such a phosphor screen 3 is formed by a method of first forming the light absorption layer 11 and then forming the three-color phosphor layers 12B, 12G and 12R by a photographic printing method.
In particular, when a phosphor layer having a color filter is formed, a filter substance-adhered phosphor in which the above pigment is adhered to gelatin as a binder in advance is used.

First, as shown in FIG. 3A, a photosensitive film containing polyvinyl alcohol (PVA) and ammonium dichromate (ADC) as main components is applied to the inner surface of the panel 1 and dried to form a photosensitive film 14. To do. And this photosensitive film 1
The shadow mask 4 is attached to the panel 1 on which 4 is formed, and a pattern corresponding to the electron beam passage hole 15 of the shadow mask 4 is printed on the photosensitive film 14. Next, the baked photosensitive film 14 of this pattern is developed with hot water to remove the unexposed portion, and a striped resist 16 is formed on the inner surface of the panel 1 as shown in FIG. Next, a black light absorbing paint is applied to the inner surface of the panel 1 on which the resist 16 is formed and dried to form a light absorbing paint film 17 as shown in FIG. Next, the light absorbing paint film 17 applied on the resist 16 is peeled off together with the resist 16 by using a release agent, and as shown in FIG. To form.

Thereafter, as shown in (e), a filter substance-adhered blue phosphor, PVA, and ADC on the inner surface of the panel 1 on which the light absorbing layer 11 is formed, for example, ultramarine is adhered with gelatin as a binder. A blue phosphor slurry layer 1 containing a photosensitive blue phosphor slurry containing as a main component and being dried.
9 is formed. Then, the shadow mask 4 is attached to the panel 1 on which the blue phosphor slurry layer 19 is formed, and a pattern corresponding to the electron beam passage holes 15 of the shadow mask 4 is printed on the blue phosphor slurry layer 19. Next, the baked blue phosphor slurry layer 19 of this pattern is developed with warm water, and as shown in (f), stripe-shaped blue having ultramarine as a color filter in a predetermined gap portion of the light absorption layer 11. The phosphor layer 12B is formed. Next, for the green and red phosphors, the method for forming the blue phosphor layer 12B is sequentially repeated,
As shown in (g), stripe-shaped green and red phosphor layers 12G and 12R are formed in predetermined gaps of the light absorption layer 11. In this case, when forming the green and red phosphor layers 12G and 12R having filters, the filter substance-adhered green and red phosphors coated with the above pigments are used, and the phosphor layers 12G and 12G having no filter are used. When forming 12R, green and red phosphors which do not deposit a filter substance are used.

In Table 3, for the blue phosphor, the average particle size of the three-color phosphor is changed, and for the blue phosphor, 5% by weight of ultramarine blue is adhered to the phosphor, and the blue phosphor is used as a filter substance. For the red phosphor, a phosphor coated with a filter substance or a phosphor not coated with a filter substance is used, and for the blue phosphor, 3.0 wt% of the total weight of the phosphor slurry excluding the phosphor is used. Using a phosphor slurry whose viscosity was adjusted by adding PVA, 3.5 wt% of PVA with respect to the total weight of the phosphor slurry excluding the phosphor was used for the green phosphor, and phosphor slurry was used for the red phosphor. By using the phosphor slurry whose viscosity was adjusted by adding PVA in an amount of 3.2% by weight based on the total weight excluding the phosphor, the blue, green, and red were sequentially prepared by the above method.
The degree of residual residues of green and red phosphors (color mixture), white brightness, and external light reflectance with respect to the blue phosphor layer 12B when the color phosphor layers 12B, 12G, and 12R are formed by coating are shown.

[0024]

[Table 3] The external light reflectance shown in Table 3 is 45 with respect to the outer surface of the central portion of the panel 1 of the color picture tube, as shown in FIG.
Light with a constant illuminance is projected from a light source 21 at an angle of °, and the reflected light is measured by a luminance meter 22 arranged opposite to the front side of the panel 1, and the brightness of the reflected light and the reflected light on a standard white plate are measured. It is a relative reflectance in which the external light reflectance of E (when the average particle size of the blue phosphor is 7.1 μm) shown as a comparative example is expressed as 100, which is the ratio to the brightness.

As shown in A to D of Table 3, a blue phosphor having an average particle size of 6.4 ± 0.3 μm and an average particle size of 5.5.
When the fluorescent surface 3 having a color filter is formed on at least the blue phosphor layer 12B by using green and red phosphors of ± 0.5 μm, the viscosity of the phosphor slurry for forming the blue phosphor layer is optimized, It is possible to maintain the white brightness and the external light reflectance at the same level as in Comparative Example E without reducing the process yield, and reduce the residues of the green and red phosphors on the blue phosphor layer 12B that is first formed by coating. It is possible to construct a color picture tube that has high contrast and no color mixture and excellent white uniformity.

Further, in Table 4, the blue phosphor is a filter substance-adhered blue phosphor coated with 5% by weight of ultramarine blue, and the green and red phosphors are not coated with the filter substance. 3.2% by weight based on the total weight of the phosphor slurry, excluding the phosphor, using the phosphor and the blue phosphor.
The phosphor slurry whose viscosity was adjusted by adding PVA of PVA was used. For the green phosphor, 3.0% by weight of PVA with respect to the total weight of the phosphor slurry excluding the phosphor, and for the red phosphor, the phosphor 2. Based on the total weight of the slurry excluding the phosphor.
Using a phosphor slurry whose viscosity has been adjusted by adding 5% by weight of PVA, three-color phosphor layers 12B and 12G are formed in the order of green, blue, and red.
, 12R are shown, and the degree of residue of red phosphor on the blue phosphor layer 12B, white brightness, and external light reflectance are shown. The external light reflectance shown in Table 4 was measured in the same manner as the external light reflectance shown in Table 3, and E shown as a comparative example.
This is a relative reflectance in which the external light reflectance (when the average particle diameter of the blue phosphor is 7.2 μm) is 100.

[0027]

[Table 4] Thus, even if the phosphor slurry is applied in the order of green, blue, and red to form the three-color phosphor layers 12B, 12G, and 12R, the red phosphor that is subsequently applied to the blue phosphor layer 12B is It is shown that the residue can be reduced and an effect similar to that in the case shown in Table 3 above can be obtained.

In the above embodiment, the average particle size of the blue phosphor is set to 6.4 ± 0.3 μm. However, if it is larger than 6.4 + 0.3 μm = 6.7 μm, the average particle size of the blue phosphor to the blue phosphor layer 12B is reduced. Residues of green and red phosphors increase. For that reason, if the amount of PVA in the phosphor slurry is reduced, defects in the phosphor slurry application process increase. If it is smaller than 6.4-0.3 μm = 6.1 μm, it is necessary to increase the amount of the color filter substance in order to prevent the decrease of the external light reflectance.
As a result, the white brightness is reduced.

For the green and red phosphors, the average particle size was set to 5.5 ± 0.5 μm, but if it is larger than 5.5 + 0.5 μm = 6.0 μm, the optimum coating amount of the phosphor increases. However, the manufacturing cost becomes high. If it is smaller than 5.5-0.5 μm = 5.0 μm, as shown in Table 5 for the relationship between the average particle size of the red phosphor and the brightness when the optimum coating amount is applied, the decrease in brightness becomes large. .

[0030]

[Table 5] In the above embodiment, the color picture tube having the fluorescent screen in which the stripe-shaped three-color phosphor layer is formed in the gap portion of the stripe-shaped light absorption layer has been described. 3 dots in the gap of the absorption layer
The same can be applied to a color picture tube having a phosphor screen having a color phosphor layer formed thereon and a phosphor screen having no light absorption layer.

[0031]

EFFECT OF THE INVENTION A color picture tube in which at least the blue phosphor layer among the three-color phosphor layers constituting the phosphor screen is composed of a phosphor layer having a filter which selectively absorbs light in a specific wavelength region with respect to external light. In each of the three-color phosphor layers, the average particle size of the blue phosphor is 6.4 ± 0.3 μm.
Assuming that the green phosphor and the red phosphor have an average particle diameter of 5.5 ± 0.5 μm, the process steps can be performed by optimizing the viscosity of the phosphor slurry for forming the blue phosphor layer. It is possible to maintain the white brightness and the external light reflectance at the same level as in Comparative Example E without lowering the amount of residue, and to reduce the residue of the green and red phosphors on the blue phosphor layer, resulting in high contrast and no color mixture and white. It is possible to construct a color picture tube with excellent uniformity.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color picture tube according to an embodiment of the present invention.

FIG. 2 (a) is a plan view showing the structure of the phosphor screen,
FIG. 2B is a sectional view thereof.

3A to 3G are views for explaining a method of forming the phosphor screen.

FIG. 4 is a diagram for explaining a method for measuring the external light reflectance of the phosphor screen.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Panel 3 ... Phosphor screen 11 ... Light absorption layer 12B ... Blue phosphor layer 12G ... Green phosphor layer 12R ... Red phosphor layer

Claims (1)

[Claims] 1. A panel which emits blue, green and red light on the inner surface 3
A color provided with a phosphor screen having a color phosphor layer, and at least the blue phosphor layer of the three-color phosphor layers is a filter substance-coated blue phosphor that selectively absorbs light in a specific wavelength region with respect to external light. In the picture tube, each color phosphor constituting the three-color phosphor layer is composed of a phosphor having an average particle size of 6.4 ± 0.3 μm for the blue phosphor and an average particle size for the green and red phosphors. Diameter 5.5
A color picture tube comprising a phosphor of ± 0.5 μm.