JP3450550B2 - Color picture tube - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube, and more particularly to a filter material in which a phosphor layer constituting a phosphor screen selectively absorbs light in a specific wavelength region. The present invention relates to a color picture tube made of a fluorescent substance to be adhered. 2. Description of the Related Art In general, a color picture tube has an envelope composed of a panel and a funnel.
A phosphor screen including a three-color phosphor layer that emits blue, green, and red light 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 the electron gun are deflected by horizontal and vertical deflection magnetic fields generated by a deflecting device mounted outside the funnel to scan the fluorescent screen horizontally and vertically, thereby forming a color image. It is formed in a structure for displaying. Among such color picture tubes, at present, in particular, an inline-type color in which a three-color phosphor layer on a phosphor screen is formed in a stripe shape and an electron gun emits three electron beams arranged in a line passing on 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, each of the three color phosphor layers selectively transmits the emission color of each phosphor without attenuating as much as possible,
It is also 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, it is possible to greatly reduce the reflection of external light on the phosphor screen without impairing the light emission of each phosphor, thereby improving the contrast of an image drawn on the phosphor screen. As a method of forming such a color filter, Japanese Patent Application Laid-Open No. 50-56146 discloses a three-color phosphor coated with fine particles of a filter substance corresponding to its emission color. Using,
A method for forming a filter is shown. As the filter substance, a pigment such as cobalt aluminate or ultramarine blue is used for the blue phosphor, chromium green or cobalt green is used for the green phosphor, and pigments such as wax 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 a three-color phosphor layer on a phosphor screen of a color picture tube in view of luminance and phosphor screen quality. From the viewpoint 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 luminance. Therefore, if the particle size of the phosphor is selected so that the luminance and the quality of the phosphor screen are practically acceptable, a phosphor screen having excellent cost performance can be formed. On the other hand, the color filter provided for improving the contrast under bright external light includes a blue filter substance of about 1 to 5% by weight with respect to the phosphor particles for the blue phosphor, and a red filter for the red phosphor. For phosphors, 0.1 to
About 0.2% of red filter material is used. As described above, in general, the three-color phosphor layer constituting the phosphor screen of a color picture tube has an average particle size of about 7 μm from the viewpoint of luminance and phosphor screen quality. The front and rear phosphors are used. On the other hand, in order to improve the contrast under bright external 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 the red phosphor, about 0.1 to 0.2% by weight of a red filter substance is used. However, when a color filter is provided as described above, particularly for a blue phosphor, the amount of the blue filter substance used is large, and thus a problem of a decrease in luminance is a problem. That is, as shown in Table 1 for the phosphors having 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 as a relative value, and When the amount of the filter substance is adjusted so that the external light reflectance is substantially the same, the luminance decreases from 100 to 90. [Table 1] Further, when forming a phosphor screen, if a three-color phosphor layer is 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 a so-called color mixture and deteriorating color purity and white uniformity. As a countermeasure against this color mixing, the viscosity is usually reduced by reducing the amount of polyvinyl alcohol (PVA) in the photosensitive blue phosphor slurry applied when forming the blue phosphor layer. When the viscosity of the photosensitive phosphor slurry is reduced by reducing the viscosity, bubbles tend to be generated at the time of slurry application, and as shown in Table 2, the rate of occurrence of defective bubbles in the slurry application step increases. [Table 2] SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it has been proposed that luminance degradation, color purity, and white uniformity in a color picture tube provided with a phosphor screen composed of a phosphor layer having a color filter are improved. The purpose is to prevent deterioration. Means for Solving the Problems Blue, green, and blue are provided on the inner surface of the panel.
A phosphor screen having a three-color phosphor layer that emits red light is provided,
In a color picture tube made of a phosphor layer with filter its three-color phosphor layers sac Chi least blue phosphor layer absorbs the light of the selectively specified wavelength region with respect to the outside light, the three-color phosphor layers Each of the constituent phosphors is a blue phosphor having an average particle diameter of 6.4 ± 0.3 μm, and a green and red phosphor having an average particle diameter of 5.5 ± 0.5 μm. did. Here, the filter that selectively absorbs light in a specific wavelength region with respect to external light is a filter that selectively absorbs light other than the emission color of the phosphor 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, chromium green or cobalt green is used for the green phosphor, and pigments such as wax and molybdenum orange are used for the red phosphor. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a color picture tube which is one embodiment of the present invention. The color picture tube has an envelope composed of a panel 1 and a funnel 2 having a funnel shape. A stripe-type phosphor screen 3 described later is provided on the inner surface of the panel 1. The shadow mask 4 is arranged inside. On the other hand, in a neck 5 of the funnel 2, an electron gun 7 that emits three electron bicycloalkyl over beam 6B arranged in a line passing on the same horizontal plane, 6G, and 6R is disposed. Then, this 3 electron beam over beam 6B emitted from the electron gun 7, 6G, and deflected by a magnetic field generated by a 6R deflection device mounted outside the funnel 2. 9, the phosphor screen 3 horizontal and vertical scanning Thereby, it is formed in a structure for displaying a color image. As shown in FIG. 2, the fluorescent screen 3 has a vertically elongated striped light absorbing layer 11 arranged in parallel at a predetermined interval in the horizontal direction, and is buried in a gap between the light absorbing layers 11. , Three-color phosphor layers 12B, 12G, which are elongated in the vertical direction and emit blue, green, and red light.
12R. The three color phosphor layers 12B, 12G,
12R, at least the blue phosphor layer 12B includes a filter that selectively transmits the emission color of the blue phosphor constituting the blue phosphor layer 12B and selectively absorbs incident external light. Has become. This filter includes 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 made of a pigment (filter material) such as vanadium or molybdenum orange. Particularly, in the color picture tube of this embodiment, the blue phosphor layer 12B is composed of a blue phosphor having an average particle diameter of 6.4 ± 0.3 μm, and the green and red phosphor layers 12G, 12G are formed.
12R are each composed of green and red phosphors having an average particle size of 5.5 ± 0.5 μm. Such a phosphor screen 3 is formed by forming a light absorbing layer 11 first and then forming three-color phosphor layers 12B, 12G and 12R by a photographic printing method.
In particular, when a phosphor layer having a color filter is to be formed, a filter substance-coated phosphor in which gelatin or the like has been previously coated with the pigment using a binder such as gelatin is used. First, as shown in FIG. 3A, a photosensitive agent 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. I do. And this photosensitive film 1
The shadow mask 4 is mounted on the panel 1 on which the pattern 4 is formed, and a pattern corresponding to the electron beam passage holes 15 of the shadow mask 4 is printed on the photosensitive film 14. Next, the photosensitive film 14 on which the pattern is baked is developed with hot water to remove the unexposed portions, and a stripe-shaped 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 peeling agent, and the stripe-shaped light-absorbing layer 11 is formed on the inner surface of the panel 1 as shown in FIG. To form Thereafter, as shown in FIG. 3E, a filter substance-coated blue phosphor, PVA and ADC, for example, coated with ultramarine with gelatin as a binder, are formed on the inner surface of the panel 1 on which the light absorbing layer 11 is formed. A blue phosphor slurry layer 1 comprising a photosensitive blue phosphor slurry containing
9 is formed. Then, the shadow mask 4 is mounted on 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 with this pattern is developed with hot water, and as shown in (f), a striped blue color filter using ultramarine blue as a color filter is provided in a predetermined gap of the light absorbing layer 11. The phosphor layer 12B is formed. Next, for the green and red phosphors, the above-described method of forming the blue phosphor layer 12B is sequentially repeated,
As shown in FIG. 2G, striped green and red phosphor layers 12G and 12R are formed in predetermined gaps of the light absorbing layer 11. In this case, when forming the green and red phosphor layers 12G and 12R having the filters, the filter substance-coated green and red phosphors coated with the pigment are used, and the phosphor layers 12G and 12G without the filter are used. When forming 12R, green and red phosphors that do not deposit filter material are used. Table 3 shows that the average particle size of the three-color phosphor was changed, and for the blue phosphor, a filter substance-coated blue phosphor in which 5% by weight of ultramarine blue was applied to the phosphor was used. For the red phosphor, a phosphor with or without a filter substance is used, and for the blue phosphor, 3.0% by weight based on the total weight of the phosphor slurry excluding the phosphor. A phosphor slurry whose viscosity was adjusted by adding PVA was used. For the green phosphor, 3.5% by weight of PVA with respect to the total weight of the phosphor slurry excluding the phosphor, and for the red phosphor, the phosphor slurry was used. Using a phosphor slurry whose viscosity has been adjusted by adding 3.2% by weight of PVA based on the total weight excluding the phosphor of the above, the blue, green, and red are used in the order of 3 by the above method.
The graph shows the degree of green and red phosphor residues (color mixture), white luminance, 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. [Table 3] As shown in FIG. 4, the external light reflectance shown in Table 3 is 45 ° relative to the outer surface of the central portion of the panel 1 of the color picture tube.
A light having a constant illuminance is projected from the 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 to determine the brightness of the reflected light and the reflected light from the standard white plate. The relative reflectance with respect to the brightness is expressed assuming that the external light reflectance of E (when the average particle diameter of the blue phosphor is 7.1 μm) shown as a comparative example is 100. As shown in Tables 3A to 3D, a blue phosphor having an average particle size of 6.4 ± 0.3 μm and an average particle size of 5.5 were obtained.
When the phosphor screen 3 having a color filter is formed on at least the blue phosphor layer 12B using green and red phosphors of ± 0.5 μm, by optimizing the viscosity of the phosphor slurry for forming the blue phosphor layer, Without lowering the process yield, the white luminance and the external light reflectance can be maintained at the same level as those of Comparative Example E, and the residues of green and red phosphors in the blue phosphor layer 12B formed first can be reduced. A high-contrast color picture tube having excellent white uniformity without color mixture can be constructed. Table 4 shows that a blue fluorescent substance coated with 5% by weight of ultramarine blue is used as a filter substance-coated blue fluorescent substance, and green and red fluorescent substances are not coated with a filter substance. The phosphor is used, and the weight of the blue phosphor is 3.2% by weight based on the total weight of the phosphor slurry excluding the phosphor.
The phosphor slurry whose viscosity was adjusted by adding PVA was used. For the green phosphor, 3.0% by weight of PVA based on the total weight of the phosphor slurry excluding the phosphor, and for the red phosphor, the phosphor was used. 2. Based on the total weight of the slurry excluding the phosphor.
Using the phosphor slurry whose viscosity was adjusted by adding 5% by weight of PVA, the phosphors having the average particle diameters shown in A and E in Table 3 were used.
The extent of the red phosphor residue on the blue phosphor layer 12B when the three color phosphor layers 12B, 12G, and 12R are applied and formed in the order of green , blue, and red, which is different from the application forming order shown in Table 3 , Shows white luminance and external light reflectance. 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 (average particle diameter of blue phosphor shown as a comparative example)
(In the case of 7.1 μm). [Table 4] As described above, 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 applied to the blue phosphor layer 12B after that is coated. It is shown that the residue can be reduced and almost the same effect as in the case shown in Table 3 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 the average particle size is larger than 6.4 + 0.3 μm = 6.7 μm, the blue phosphor layer 12B has a larger particle diameter. Green and red phosphor residues increase. In addition, if the amount of PVA in the phosphor slurry is reduced for this reason, defects in the phosphor slurry application step increase. When 6.4−0.3 μm = 6.1 μm or less, it is necessary to increase the amount of the color filter substance in order to prevent a decrease in external light reflectance.
As a result, the white luminance decreases. The average particle diameter of the green and red phosphors is set to 5.5 ± 0.5 μm. However, if the average particle diameter is larger than 5.5 + 0.5 μm = 6.0 μm, the optimum coating amount of the phosphor increases. And the manufacturing cost increases. Further, when it is smaller than 5.5-0.5 μm = 5.0 μm, as shown in Table 5, the relationship between the average particle size and the luminance when the optimal coating amount is applied to the red phosphor, the luminance decrease becomes large. . [Table 5] In the above-described embodiment, the color picture tube having the phosphor screen in which the stripe-shaped three-color phosphor layers are formed in the gaps between the stripe-shaped light absorption layers has been described. Dot-shaped 3
The present invention can be similarly applied to a color picture tube provided with a phosphor screen having a color phosphor layer formed thereon and a phosphor screen having no light absorbing layer. As described above, at least the blue phosphor layer among the three color phosphor layers constituting the phosphor screen is formed of a phosphor layer having a filter for selectively absorbing light in a specific wavelength region with respect to external light. In the color picture tube, each color phosphor constituting the three-color phosphor layer is represented by an average particle diameter of 6.4 ± 0.3 μm for the blue phosphor.
Assuming that the green and red phosphors are phosphors having an average particle size of 5.5 ± 0.5 μm, the viscosity of the phosphor slurry for forming the blue phosphor layer is optimized and the process steps are performed. Without lowering the retention, the white luminance and the external light reflectance were maintained at the same level as those of Comparative Example E, and the residues of the green and red phosphors on the blue phosphor layer could be reduced. A color picture tube with excellent uniformity can be constructed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of a color picture tube according to an embodiment of the present invention. FIG. 2A is a plan view showing the configuration of the phosphor screen,
FIG. 2B is a cross-sectional view thereof. FIGS. 3A to 3G are diagrams for explaining a method of forming the fluorescent screen. FIG. 4 is a diagram for explaining a method of measuring the external light reflectance of a phosphor screen. [Description of Signs] 1 ... Panel 3 ... Fluorescent screen 11 ... Light absorbing layer 12B ... Blue phosphor layer 12G ... Green phosphor layer 12R ... Red phosphor layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01J 29/20 H01J 29/32 H01J 9/227

Claims (1)

(57) [Claims] [Claim 1] 3 that emits blue, green and red light on the inner surface of the panel
A phosphor screen having a color phosphor layer;
In a color picture tube made of filter material covering the blue phosphor at least blue phosphor layer Chi caries layer absorbs light of a selective specific wavelength region with respect to the outside light, each color fluorescent constituting the three-color phosphor layers The body is composed of a phosphor having an average particle diameter of 6.4 ± 0.3 μm for the blue phosphor and an average particle diameter of 5.5 for the green and red phosphors.
A color picture tube comprising a phosphor of ± 0.5 μm.