JPH01178584A - Color television phosphor - Google Patents

Abstract

PURPOSE:To provide a color television phosphor excellent in dispersibility and capable of being efficiently formed into a uniform and dense phosphor film on a color cathode ray tube, by adhering a silicate or phosphate and a bivalent or tetravalent tin compd. on the surfaces of phosphor particles. CONSTITUTION:An aqueous solution of a tin salt such as SnCl4 or Sn(SO4)2 is added to an aqueous suspension prepd. by suspending phosphor particles in water. An alkali such as aqueous ammonia or NaOH is added to the resulting mixture with stirring to adjust the pH thereof to 6-8, whereby the tin salt is hydrolyzed to adhere at most 1pt.wt. bivalent or tetravalent tin compd. to the surfaces of 100pts.wt. phosphor particles, which are then dried at 100 deg.C or below. The treated phosphor particles are dispersed in water to prepare an aqueous suspension, to which an aqueous soln. contg. a silicate (e.g., K2SiO3) or a phosphate (e.g., AlPO4) is added to adhere at most 2pts.wt. silicate or phosphate to the surfaces of 100pts.wt. phosphor particles.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a phosphor used in a cathode ray tube for color television, and more particularly to a phosphor for a color aralan tube in which a phosphor film is formed by a slurry 4 coating method. [Prior Art and its Problems] Generally, a slurry coating method is employed to form a fluorescent film for a color television. This slurry coating method uses optical printing technology. In this method, first, phosphor particles are dispersed in a photosensitive resin solution containing, for example, polyvinyl alcohol (PVA) and ammonium dichromate. This photosensitive resin solution in which phosphor particles are dispersed is called a phosphor slurry solution. This phosphor slurry solution is uniformly applied to the inner surface of the glass panel, and then exposed and developed using well-known photoprinting technology to form regularly arranged stripes or dots in the desired shape on the inner surface of the glass panel. It is formed. Then, by repeating these steps for each of the blue, green, and red phosphors, a phosphor film is formed. It is especially important for the phosphor used in such a slurry coating method to have good dispersibility in the phosphor slurry solution. That is, if the dispersibility of the phosphor is poor, the end shape of the stripes or dots becomes poor, the phosphor film cannot be formed uniformly or densely, and the characteristics of the phosphor film deteriorate. Furthermore, depending on the dispersibility of the phosphor, the exposure sensitivity of the slurry solution decreases, resulting in a decrease in workability in forming the phosphor film. For this reason, conventionally, silicon compounds and phosphate compounds such as silicon dioxide, zinc silicate, and aluminum silicate have been attached to the surface of the phosphor to improve its dispersibility. A technique has been developed for attaching silicon dioxide, aluminum compounds, and zinc compounds of specific particle diameters to the surface of phosphor particles (Japanese Patent Publication No. 46512/1983). However, when manufacturing high-definition color cathode ray tubes using conventional phosphors attached with these substances,
In either case, good dispersibility was not obtained, and it was necessary to make it uniform and dense.
Moreover, it is difficult to obtain a high-definition fluorescent film with excellent edge formation. In other words, the phosphor film of high-definition color cathode ray tubes, which requires small stripes or dots, uses phosphors in extremely thin dots, for example, with a dot pitch of 0.4 mm or less. Phosphors need to be adhered, but if the phosphor does not have sufficient dispersibility, fine dots cannot be accurately adhered with neat contours. [Problems to be solved by the invention This invention has been made in view of the above-mentioned circumstances,
The purpose is to have extremely excellent dispersibility,
To provide a television phosphor capable of efficiently forming a uniform and dense phosphor film when forming a phosphor film for a color cathode ray tube. [Means for Solving the Problems] In order to achieve the above-mentioned object, the phosphor of the present invention further contains 2 silicate or phosphate on the surface of the phosphor particles.
A valent or tetravalent tin compound is attached. The amount of attached tin contained in the tin compound is adjusted to 1 part by weight or less per 100 parts of the phosphor, and the amount of attached silicate or phosphate is adjusted to less than 2 parts by weight. As the divalent or tetravalent tin compound, preferably tin hydroxide, iii, or organic tin can be used. As the silicate, zinc silicate, aluminum silicate, magnesium silicate, etc. are preferably used alone or in combination. As the phosphate, zinc phosphate, aluminum phosphate, magnesium phosphate, etc. are preferably used alone or in combination. [Action] A divalent or tetravalent tin compound, for example, stannic acid,
(IV) Hydrate (SnO2.nH2O), and this tin(IV) oxide hydrate adsorbing alkali is a colloidal solution and does not have a fixed composition. The phosphor particles of the present invention, on which stannic acid is added to silicate or phosphate, have a smooth surface after drying, and the phosphor particles can be coated with a phosphor slurry solution in a slurry coating method. When the phosphor particles are suspended, they exhibit extremely good dispersibility for forming a phosphor film. Similarly, tin hydroxide [Sn(OH)2] also easily forms colloids and does not have a fixed composition, but phosphor particles with tin hydroxide added to silicate or phosphate and attached to the surface are When phosphor particles are suspended in a phosphor slurry solution in a coating method, they exhibit extremely good dispersibility for forming a phosphor film. The phosphor of the present invention has a divalent or tetravalent tin compound attached in addition to the silicate or phosphate;
depositing silicates or phosphates alone on the surface, or
It exhibits excellent dispersibility that cannot be achieved with phosphors that adhere solely to tin compounds. The reason for this is not clear, but the phosphor of the present invention has both a silicate or phosphate and a divalent or tetravalent tin compound attached to its surface, causing repulsion due to the electric charge. it is conceivable that. Furthermore, it goes without saying that good dispersibility is exhibited even when tin hydroxide, organic tin, or stannic acid is attached to the surface of the phosphor particles. [Preferred Embodiment] Prior to the embodiments of the present invention, a method for attaching a divalent or tetravalent tin compound to the surface of phosphor particles will be described below. The divalent or tetravalent tin compound used in the present invention, i.e.
Tin oxide and tin hydroxide include SnCα4, Sn(SO4)2.
Hydrolyzed tin salts such as 5n(No)4 can be used, and organic tins include Sn(CH-Coo)4.5n(C-
0) 4 etc. can be used. That is, in the method of obtaining tin hydroxide by hydrolyzing a tin salt, first, phosphor particles to be deposited are suspended in water, and a predetermined amount of a tin salt aqueous solution, for example, a SnCα4 aqueous solution is added. While stirring the phosphor suspension to which the SnCα4 aqueous solution has been added, the pH is adjusted to 6 to 8 using an alkali such as aqueous ammonia or sodium hydroxide, thereby hydrolyzing the suspension. As a result, a divalent tin compound, that is, tin hydroxide [S n (OH) 2] is attached to the surface of the phosphor particles. By performing the same method as described above except for adding an aqueous solution of tin organic acid salt, 2
A valent or tetravalent tin compound, ie tin oxide and/or tin hydroxide, is deposited. Drying is performed at a temperature of less than 100° C. to allow tin hydroxide or organic tin to be adsorbed onto the surface of the phosphor. Examples of the present invention will be described below.

[Example 1] After suspending 100 g of silver-activated zinc sulfide phosphor in 250 tnα of pure water, 2.5 mα of SnCα4 aqueous solution (2% Sn-containing solution) was added to this phosphor suspension, and the mixture was heated for 5 minutes. Stirred. While stirring, a 5% aqueous NaOH solution was added dropwise to adjust the pH to 6.5, then stirring was stopped and the phosphor particles were allowed to settle. Then filtered and dried (3 hours at 90°C)
By passing the particles through a 300-mesh sieve, a phosphor having a tin compound, that is, tin hydroxide attached to the surface of the phosphor particles was obtained. Next, 100 g of silver-activated zinc sulfide phosphor with tin hydroxide attached to its surface was suspended in 250 m of pure water, and the phosphor was suspended in i? If(:I(2S i 03(S iO2
A solution containing 2% Zn) was added with stirring for 1 m, and then 0.5 m
Add α and stir. While stirring, add 2% NaOH
Add the aqueous solution dropwise and adjust the pH to 6.8. After 30 minutes, 2.5 m of SnCα4 (solution containing 2% S11)
M was added and mixed, a 5% NaOH aqueous solution was added dropwise, the pH was adjusted to 6.5, and the phosphor particles were precipitated. Thereafter, the mixture was filtered, dried (at 90° C. for 10 hours), and passed through a 300-mesh sieve to obtain a phosphor having tin hydroxide and zinc silicate attached to the surface of the phosphor particles. Using the obtained tin hydroxide-attached phosphor, a stripe was formed by the usual slurry coating method as described below, and compared with a conventional stripe that was similar to the above except that zinc silicate was attached. 6g of tin hydroxide-attached silver-activated zinc sulfide phosphor, PVA0
．． A phosphor slurry solution was prepared by suspending the phosphor in a 220 m photosensitive resin solution containing 3 g of ammonium dichromate. This phosphor slurry is applied to the glass panel surface, and as shown in FIG.
A stripe with a width of 71 m was formed. To judge the quality of the end of the stripe, as shown in Figure 3, measure the maximum width (A) and minimum width (B) of the stripe, and calculate the difference (A-B) between the stripes. It was taken as a live value. The stripe coated with the phosphor obtained in Example 1 had a uniform thickness and was dense. In addition, when measuring the stripe shape of a silver-activated zinc sulfide phosphor (conventional phosphor) similar to Example 1 except that only zinc silicate was attached without attaching tin hydroxide, A = 3.
30 μm, B = 300 μm, and the stripe value is 30 μm, whereas the phosphor obtained in Example 1 of the present invention has A = 320 μm, B = 300 μm.
The stripe value was 207 zm, an improvement of 50% compared to conventional phosphors. That is, in the phosphor obtained in Example 1, by attaching tin hydroxide in addition to zinc silicate, the contour shape of the stripes could be significantly improved.

[Example 2] After suspending 100 g of copper and aluminum co-activated zinc sulfide phosphor in 250 mjl of pure water, 10 mj of a 5n(Sn4)2 aqueous solution (liquid containing 2% Sn) was added to this phosphor suspension.
1 was added and stirred for 5 minutes. While stirring, add 2% N
After dropping the Ha OH aqueous solution and adjusting the pH to 6.5, stirring was stopped and the phosphor particles were allowed to settle. Thereafter, the particles were filtered, dried, and passed through a 300-mesh sieve to obtain a phosphor having a tin compound, that is, tin hydroxide attached to the surface of the phosphor particles. Next, 100 g of steel and aluminum-activated zinc sulfide phosphor with tin hydroxide attached to the surface were suspended in 250 mQ of pure water, and then 2S i 03 was added to this phosphor suspension.
(a solution containing 2% S i 02) was added at 1°5 mM with stirring, and further, 0.75 mjl of ZnSOm (a solution containing 2% Zn) was added and stirred. While stirring, 5% Nao) (aqueous solution) was added dropwise to adjust the pH to 7.
Adjust to 0. After 30 minutes, Sn (Son) 2'
(Solution containing 2% Sn) Add and mix 10 m of bruises,
% NaOH aqueous solution was added dropwise to adjust the pH to 6.5.
The phosphor particles were allowed to settle. Thereafter, the mixture was filtered, dried (at 90° C. for 10 hours), and passed through a 300-mesh sieve to obtain a phosphor having tin hydroxide and zinc silicate attached to the surface of the phosphor particles. Next, using the obtained tin hydroxide-attached phosphor, the same stripe shape values as in Example 1 were measured. The obtained stripes had a uniform thickness and were dense. In addition, when measuring the stripe shape of the same phosphor (conventional phosphor) as in Example 2 except that zinc silicate was attached instead of tin hydroxide, A: 340 μm, B = 300 μm.
m, and the stripe value is 40 μm, whereas the phosphor obtained in Example 2 of the present invention has A=320 μm,
B=300 um, and the stripe value was 20 μm, which was extremely reduced to half of the conventional value.

[Example 3] After suspending 100 g of silver-activated zinc sulfide phosphor in 250 mα of pure water, first, 2.0 g of cobalt aluminate was added to this phosphor suspension, and an acrylic emulsion (acrylic 2% 1 mA (containing) was added, the pH was adjusted to 5 with acetic acid,
It was allowed to settle and was decanted until neutral. Next, 50 m of 5n (Son) 2 aqueous TFF (solution containing 2% Sn) was added and stirred for 5 minutes. While stirring, 2% NHaOH aqueous solution was added dropwise to adjust the pH to 6. After adjusting to 0, stirring was stopped and the phosphor particles were allowed to settle. Thereafter, the mixture was filtered, dried (at 90° C. for 10 hours), and passed through a 300-mesh sieve to obtain a phosphor having a tin compound, that is, tin hydroxide, attached to the surface of the phosphor particles. Next, 100 g of a silver-activated zinc sulfide phosphor with tin hydroxide attached to its surface was suspended in 25 liters of pure water, and then cobalt 2 aluminate was added to this suspension. g and 1 ml of acrylic emulsion (containing 2% acrylic) were added, the pH was adjusted to 5 with acetic acid, and the phosphor was precipitated and decanted until it became neutral. Furthermore, K2S i 03 (a solution containing 2% S i 02) was added while stirring for 1 m, and then Zn5O
Add 0.5 mM of a (solution containing 2% Zn) and stir. While stirring, a 2% aqueous N Ha OH solution is added dropwise to adjust the pH to 6.8. Sara ζ Komata, Sn
(SO4)2 (solution containing 2% Sn) 50mQ
Add and mix, add 5% N HaOH aqueous solution dropwise, and add p
The t-t was adjusted to 6.0 to allow the phosphor particles to settle. Thereafter, it was filtered, dried (at 90° C. for 10 hours), and passed through a 300-mesh sieve to obtain a pigmented phosphor in which tin hydroxide and zinc silicate were adhered to the surface of the phosphor particles. Next, using the obtained phosphor, the value of the stripe shape was measured in the same manner as in Example 1. The obtained stripes had a uniform thickness and were dense. In addition, in the measurement of the stripe shape using the same phosphor (conventional phosphor) as in Example 3 except that only zinc silicate was attached without attaching tin hydroxide, A = 320 μm, B = 30 μm.
0 μm, and the stripe value is 20 μm. However, in the measurement of the stripe shape using the phosphor obtained in Example 3 of the present invention, A = 310 m, B = 300 ttm.
The stripe value was extremely reduced to 50% to 10 μm.

[Example 4] Europium-activated yttrium oxysulfide phosphor (Y202
After suspending 100 g of S/E u ) in 25 Orrl of pure water, 5 mM of sodium alginate solution (5% solution) was added to this phosphor suspension, and the pH was adjusted to 5 with acetic acid. %N HaOH aqueous solution was added dropwise to adjust the pH to 7.
．． After adjusting to 0, stirring was stopped and the phosphor particles were allowed to settle. After that, it was filtered, dried (3 hours at 90°C) and heated to 300°C.
By passing the particles through a mesh sieve, a phosphor having tin alginate attached to the surface of the phosphor particles was obtained. Next, this phosphor was treated in the same manner as in Example 1 to obtain a phosphor in which tin alginate and zinc silicate were attached to the surface of the phosphor particles. In the above examples, zinc silicate is used as the silicate.
Instead of zinc silicate, it is also possible to use aluminum silicate or magnesium silicate. It is also possible to use zinc phosphate, aluminum phosphate, or magnesium phosphate instead of silicate. In the phosphor of the present invention, the tin oxide 1 contained in the tin compound is
The amount is usually adjusted to 1 part by weight or less, preferably from 0.001 to 0.5 part by weight, per 100 parts by weight of the phosphor. If the amount of the tin compound attached is too large or too small, the dispersibility of the phosphor will deteriorate. Figure 1 shows the dispersibility of the tin compound with respect to the amount of tin attached. However, Figure 1 shows the sedimentation volume when the amount of zinc silicate adhering to the surface of the phosphor and the tin compound is constant at 0.5% by weight, and the coating amount of tin contained in tin hydroxide is changed. It shows. The sedimentation volume is determined by taking a certain amount of the phosphor of the present invention as a PVA-ADC slurry into a sedimentation tube and forcibly settling it in a centrifuge for a certain period of time. The smaller the settling volume, the better the dispersibility, and a phosphor with good dispersibility will adhere properly to the panel surface even if the stripe width, which is a measure of adhesive strength, becomes small. The adhesion amount of zinc silicate is 0. The phosphor is 5% by weight, and the phosphor contained in tin hydroxide is 0.01~0.05% by weight.
The dispersibility is best when /li is higher or lower, and the falling volume increases and the adhesive strength decreases. Therefore, the amount of the single compound attached is adjusted within the above-mentioned range, taking into consideration the dispersibility required of the phosphor. In the above embodiment, a tetravalent tin salt is used as an additive for the tin compound attached to the surface of the phosphor particles, but the present invention is not limited to this; Tin salts of 30% and 30% may also be used. This is because divalent tin salt is chemically unstable and substantially changes to tetravalent tin salt. Further, in the above embodiments, zinc sulfide phosphor is used as the phosphor particles, but according to the present invention, the present invention is not limited to this, and rare earth red light-emitting phosphors such as yttrium oxysulfide phosphors can be used. It may also be applied to silicon dioxide,
It can also be applied to pigmented red light emitting phosphors and pigmented blue light emitting phosphors to which pigments such as cobalt aluminate and iron oxide are attached. [Effects of the Invention] The phosphor of the present invention has excellent dispersibility for slurry used in forming phosphor films for color televisions. Therefore, by forming a phosphor film for color television using the phosphor of the present invention, a uniform and dense phosphor film can be formed. Further, the phosphor of the present invention can improve dispersion characteristics with extremely good workability, and can easily produce a television phosphor having stripes of fine dots in large quantities. FIG. 4 shows that the phosphor of the present invention exhibits excellent properties in forming fine stripes. This figure shows the relationship of stripe width to exposure amount. A phosphor with poor dispersibility has a wide stripe width, a decrease in adhesive strength at the periphery, and a large stripe value. On the other hand, a phosphor with good dispersibility has a narrow stripe width and is firmly adhered to the entire stripe. In this figure, curve A shows the characteristics of the phosphor of the present invention obtained in Example 1, and curve B
shows the characteristics of a conventional phosphor that is similar to Example 1 except that no tin compound is attached. As shown by curve A,
The phosphor of the present invention has a narrower stripe width than conventional phosphors, indicating that fine stripes can be clearly attached. It will be explained with reference to FIG. 2 that a phosphor with a narrow stripe width achieves excellent coating and sound characteristics. FIG. 2 shows the positional relationship of "light source 2 - shadow mask 1 - coating surface 3" and the distribution of the exposure amount when producing the phosphor screen. When the light from the exposure light source 2 passes through the electron beam passing holes in the shadow mask 1 and is projected onto the coating film of the photosensitive binder, the central part of the phosphor is exposed to the light that has passed through the holes in the shadow mask 1. , the shadow mask 1 allows the light to be irradiated without being blocked. However, as the distance from the hole in the shadow mask 1 increases, the light from the light source 2 is hidden by the shadow mask 1, and the exposure amount distribution takes on a trapezoidal shape. The central part (a) is called a true shadow part, and the peripheral part (a-b) is called a penumbra part, and the degree of hardening decreases sequentially from the true shadow part to the penumbra part. Therefore, how to make the true shadow part effective is
This is an important factor that determines the adhesion strength and the quality of the stripe shape. With a phosphor having good dispersibility, the phosphor particles are neatly arranged and distributed uniformly, the phosphor in the shadow area is reliably and firmly attached, and narrow stripes are clearly formed. On the other hand, with a phosphor that has poor dispersibility, the phosphor particles will not line up neatly.
The phosphor is non-uniformly deposited near the boundary between the true shadow area and the penumbra area, resulting in a wide stripe width and a large stripe value. The phosphor of the present invention has excellent coating properties as shown by curve A in FIG. 4, and can realize the feature of clearly forming stripes with a small dot pitch.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the settling volume of the phosphor of the present invention with respect to the amount of attached tin, FIG. 2 is a cross-sectional view showing the state of formation of stripes, FIG. 3 is an enlarged plan view showing the state of stripes, and FIG. The figure is a graph showing stripe width versus exposure amount. l...Shadow mask, 2...Light source, 3...Coating surface.

Claims (6)

[Claims] (1) In addition to silicate or phosphate, a divalent or tetravalent tin compound is attached to the surface of the phosphor particles, and the amount of tin included in the tin compound is equal to 100 parts by weight of the phosphor. 1. A phosphor for color television, characterized in that the amount of silicate or phosphate deposited is adjusted to be 2 parts by weight or less. (2) The phosphor for color television according to claim 1, wherein the tin compound is an organic tin. (3) The phosphor for color television according to claim 1, wherein the tin compound is tin hydroxide. (4) The phosphor for color television according to claim 1, wherein the tin compound is stannic acid. (5) The silicate is zinc silicate, aluminum silicate,
The phosphor for color television according to claim 1, which contains any one of magnesium silicate. (6) The above phosphate is zinc phosphate, aluminum phosphate,
The phosphor for color television according to claim 1, which contains any one of magnesium phosphate.