JPS6232235B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for surface treatment of phosphors. More specifically, the present invention provides a fluorescent film with less color mixture,
The present invention also relates to a surface treatment method for a phosphor that improves the exposure sensitivity of the phosphor slurry when preparing the phosphor slurry for producing the phosphor film. As is well known, the phosphor film of a color television cathode ray tube is a regular array of blue, green and red emitting dots or stripes made of blue, green and red emitting component phosphors, respectively, on a face plate. The fluorescent film of this color television cathode ray tube is produced by optical printing. That is, first, a phosphor slurry is prepared by dispersing the first luminescent component phosphor in a photosensitive resin solution such as a dichromate-activated polyvinyl alcohol aqueous solution. The resulting phosphor slurry is applied to the entire surface of the face plate using an appropriate coating method such as spin coating (slurry coating), and then the coated surface is irradiated with energy rays such as ultraviolet rays in a predetermined pattern. The resin in the exposed areas is cured and made insoluble (exposure). Thereafter, the portion irradiated with energy rays (hardened resin portion) is dissolved and removed using a solvent or the like (development) to form dots or stripes made of the first luminescent component phosphor. For the second and third luminescent component phosphors, the same series of slurry application, exposure and development operations as described above are repeated in sequence to form dots or stripes made of the second and third luminescent component phosphors. In this case, the dots or stripes of the first, second and third luminescent component phosphors do not overlap each other;
It goes without saying that the energy beam irradiation must be controlled so that it is repeatedly and regularly arranged on the face plate. Next, the fluorescent film containing the resin component obtained as described above is fired at an appropriate temperature to separate and volatilize the resin component, thereby obtaining the desired fluorescent film. When creating a phosphor film for color television cathode ray tubes by the optical printing method using the above-mentioned phosphor slurry, (1) it must have sufficient thickness and form dense dots or stripes; (2) Dots or stripes of a predetermined shape should be formed at predetermined positions on the face plate; (3) One luminescent component phosphor should not mix with other luminescent component phosphors, that is, color mixing should not occur. (4) The phosphor slurry must have high exposure sensitivity and good workability. Conventionally, in order to satisfy each of the above matters, various studies have been made regarding the composition, preparation method, etc. of phosphor slurry, and the surface treatment of color television phosphors (blue, green, and red emitting component phosphors) used in phosphor slurry. Research has been conducted. The current phosphor slurry satisfies each of the above items to some extent. However, since higher quality fluorescent films are always required commercially, it is desired to further improve each of the above points. It is an object of the present invention to provide a method for surface treatment of a phosphor that further improves especially (3) and (4) among the above matters. That is, an object of the present invention is to provide a surface-treated phosphor that provides a phosphor film with less color mixture. Another object of the present invention is to provide a phosphor for color television that has been surface-treated to improve the exposure sensitivity of the phosphor slurry when preparing the phosphor slurry for producing a phosphor film. The above objects of the present invention have been achieved by a specific surface treatment method. That is, the method for surface treatment of a phosphor of the present invention involves adding an alkali to a phosphor suspension containing a phosphor and zinc ions to adjust the pH of the suspension.
7.5 to 11, and then separating the phosphor from the suspension. Furthermore, the dispersibility of the color television phosphor in the phosphor slurry has been improved by attaching phosphates such as silicon dioxide, magnesium, zinc, calcium, and aluminum to the conventional color television phosphor. It is known that a substance that improves the dispersibility of television phosphors (hereinafter referred to as a "dispersant") can be used to obtain a good phosphor film. The surface treatment can be used in combination with this surface treatment using a dispersant. When a color television cathode ray tube phosphor film is produced by optical printing using the phosphor obtained by the surface treatment method of the present invention, the resulting phosphor film has significantly less color mixture. Further, the phosphor slurry using the phosphor of the present invention has high exposure sensitivity, and therefore the ultraviolet irradiation time (exposure time) for curing can be shortened, and work efficiency can be increased. The present invention will be explained in detail below. The phosphor surface treatment method of the present invention includes, for example, the steps described below. First, put the phosphor in pure water and suspend it thoroughly. Next, an appropriate amount of an aqueous solution containing zinc ions is added to this suspension, and then an alkali is added to the suspension containing zinc ions to adjust the pH value of the suspension to 7.5 to 11.
to precipitate a surface treatment substance such as zinc hydroxide [hereinafter abbreviated as Zn(OH) ₂ ].
The precipitated fine particles of Zn(OH) ₂ are adsorbed on the surface of the phosphor. The suspension is allowed to stand to allow the phosphor to which the Zn(OH) ₂ fine particles are attached to settle, and then the supernatant liquid is removed by decantation. After washing with water several times to remove residual ions, it is dehydrated and dried. After drying, the resulting lumpy phosphor is passed through a sieve to loosen it to obtain the desired phosphor. Examples of aqueous solutions containing zinc ions include water-soluble zinc compounds such as zinc sulfate (ZnSO ₄ ), zinc acetate [Zn
(CH ₃ COO) ₂ ], zinc nitrate [Zn(NO ₃ ) ₂ ], zinc halide (ZnX ₂ , where X is a halogen excluding fluorine), and the like are used. Further, as the alkali for adjusting the pH value, an aqueous solution of sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), etc. is used. When using NH ₄ OH, if added in excess, soluble ammine complex ions are generated and Zn(OH) ₂ does not precipitate, so the PH
Care must be taken to ensure that the value does not exceed 10. Drying is carried out at a temperature below 250°C, preferably below 200°C. When drying at a temperature higher than 250℃, Zn(OH) ₂ attached to the phosphor
are all zinc oxide compounds (hereinafter abbreviated as ZnO)
, so that the phosphor targeted by the present invention cannot be obtained. Zn when drying at 200 to 250℃
Although a part of (OH) ₂ converts to ZnO (naturally, the higher the temperature, the higher the rate of conversion to ZnO), the ZnO produced does not have any adverse effect on the phosphor properties.
When drying is carried out at temperatures below 200°C, almost no conversion to ZnO occurs, and Zn(OH) ₂ remains almost unchanged. Zn added to phosphor for color television
The amount of (OH) ₂ is more than 0 parts by weight and not more than 0.7 parts by weight based on 100 parts by weight of the phosphor for color television. If the amount of Zn(OH) ₂ deposited is more than 0.7 parts by weight, the dispersibility of the resulting phosphor gradually deteriorates, and color mixing will occur significantly when used as a phosphor film, which is not preferable. more preferable
The amount of Zn(OH) ₂ deposited is 0.01 to 0.5 parts by weight. Note that it is convenient to use concentrated ammonia water to quantify Zn(OH) ₂ attached to the phosphor. Concentrated ammonia water does not react with color television phosphors, which are mainly sulfides or oxides, or with ZnO, which is produced when high drying temperatures are used, but it selectively reacts with Zn(OH) ₂ . Generates soluble ammine complex ions. Therefore, the amount of Zn(OH) ₂ attached can be determined by treating the phosphor of the present invention with concentrated ammonia water, dissolving and separating Zn(OH) ₂ as ammine complex ions, and quantifying the ammine complex ions. I can do it. Note that when a dispersant is used in combination with the phosphor of the present invention, the dispersant may first be attached to the phosphor for color television using a conventional method, and then Zn(OH) ₂ may be attached using the method described above. It may be fine, or vice versa. Dispersants include silicon dioxide (SiO ₂ ), ortho, meta or pyrophosphates such as magnesium, zinc, calcium and aluminum [Mg ₃ (PO ₄ ) ₂ , Zn ₃ (PO ₄ ) ₂ , Ca ₃
( _PO4 ) ₂ , _AlPO4 , Mg( _PO3 ) ₂ , Zn( _PO3 ) ₂ , Ca
( _{PO3 ) 2} , _{Al ( PO3} ) ₃ , _Mg2P2O7 , _{Zn2P2O7 ,}
Ca ₂ P ₂ O ₇ etc.], but it is particularly preferable to use SiO ₂ . The dispersant is applied to the phosphor by methods known in the art. For example, in the case of SiO ₂ , the phosphor is first suspended in an aqueous water glass solution, and then an aqueous solution of zinc sulfate, aluminum sulfate, etc. is added to this suspension to precipitate SiO ₂ fine particles. A method such as adsorption to the surface of the phosphor is adopted. The phosphors used in the present invention, such as phosphors for color television, include all phosphors that can be used as blue, green or red emitting component phosphors of color television cathode ray tube phosphors. This phosphor for color television may be a single phosphor, or it may be a copper- and aluminum-activated zinc sulfide phosphor (ZnS: Cu, Al), which has recently been put into practical use, and a gold- and aluminum-activated phosphor. A mixed phosphor such as a green light-emitting component phosphor mixed with a zinc sulfide phosphor (ZnS:Au, Al) may also be used. In addition, recently, so-called pigmented phosphors, in which the surface of the phosphor is coated with pigment particles, have been used in the phosphor films of high-contrast color television cathode ray tubes. It may also be a phosphor attached. Therefore, in this specification, the expression "phosphor for color television" means any of a single phosphor, a mixed phosphor, and a pigmented phosphor, unless otherwise specified. Preferred phosphors for color television from a practical standpoint include silver-activated zinc sulfide phosphors (ZnS:Ag) and silver- and aluminum-activated zinc sulfide phosphors (ZnS:Ag, Al) as blue-emitting phosphors. , ZnS with cobalt aluminate blue pigment particles: Ag phosphor, ZnS with cobalt aluminate blue pigment particles:
Ag, Al phosphor, etc. Green emitting component phosphor, mixed phosphor of ZnS:Cu, Al phosphor and ZnS:Au, Al phosphor, ZnS:Cu, Al phosphor, activated with gold, copper and aluminum Zinc sulfide phosphor (ZnS:
Au, Cu, Al), copper and aluminum activated zinc sulfide/cadmium phosphor [(Zn, Cd)S:Cu,
Europium-activated yttrium oxysulfide phosphor (Y ₂ O ₂ S: Eu), europium-activated yttrium oxide phosphor (Y ₂ O ₃ : Eu), Y ₂ with red pigment particles as red-emitting phosphors such as _O2S :
Eu phosphor with red pigment particles Y ₂ O ₃ : Eu phosphor with cadmium selenide sulfate red pigment particles
Examples include Y ₂ O ₂ S: Eu phosphor, Y ₂ O ₃ : Eu phosphor with cadmium selenide sulfide red pigment particles, and the like. Next, the effects of the present invention will be explained using a ZnS:Ag blue-emitting component phosphor as an example. There are two types of color mixing between the luminescent component phosphors in the fluorescent film of a color television cathode ray tube. One is when the first luminescent component phosphor or the second luminescent component phosphor is slurried, exposed, and developed to form dots or stripes on the faceplate; This is a case where the phosphor remains at the position of the dots or stripes of the component phosphors, resulting in color mixture, and such residual phosphor is called "haze". The other is that when the second luminescent component phosphor or the third luminescent component phosphor is slurried, exposed, and developed to form its dots or stripes, the dots or stripes of the second luminescent component phosphor or the third luminescent component phosphor that have already been formed are The phosphor adheres to and remains on the dots or stripes, and this type of color mixing is called "cross contamination." While haze occurs depending on the characteristics of the phosphor slurry used, cross-contamination depends on both the characteristics of the phosphor slurry used and the characteristics of the underlying dots or stripes that have already been formed. It is something that occurs. The phosphor of the present invention significantly improves the color mixing caused by both the haze and cross-contamination described above. FIG. 1 is a graph showing the relationship between the amount of Zn(OH) ₂ attached and the haze of Zn(OH) ₂ attached ZnS:Ag phosphor (including the amount O attached). The graph in FIG. 1 was obtained as follows. First, 0.15 parts by weight of SiO ₂ is attached to 100 parts by weight of ZnS:Ag phosphor.
Using ZnS:Ag phosphors, seven types of Zn(OH) _2- attached ZnS:Ag phosphors with different amounts of Zn(OH) ₂ attached were manufactured. These seven types of Zn(OH) ₂ adhesion
ZnS: Ag phosphor and Zn(OH) ₂ are not attached
Eight types of phosphors, ZnS:Ag phosphor (0.15 wt% SiO ₂ attached), were used as samples. Note that these eight types of phosphor samples were also used to obtain each of the graphs shown in FIGS. 2 to 4, which will be described later.
Next, using these phosphor samples, stripes were formed on the face plate in the following manner. First, a phosphor slurry was prepared in a conventional manner using a commonly used polyvinyl alcohol aqueous solution containing ammonium dichromate and each phosphor sample. Next, each of the obtained phosphor slurries was spin-coated onto the face plate of a 16-inch cathode ray tube, dried, and then exposed to ultraviolet rays using a high-pressure mercury lamp through a shadow mask in the form of stripes, and developed with hot water. to form stripes. Note that the above method for creating stripes was also applied to obtain the graphs shown in FIGS. 2 and 4. A part of the face plate on which stripes have been formed as described above is magnified 100 times and projected onto a screen using a magnifying projection microscope. The number of phosphor particles (haze) remaining on the face plate (0.2 mm x 0.2 mm) was counted. For each phosphor sample, the number of phosphor particles was counted at two locations, and the average value was calculated as the amount of Zn(OH) ₂ deposited on each phosphor sample (ZnS:Ag phosphor
The graph shown in FIG. 1 was obtained by plotting the ratio of 100 parts by weight to 100 parts by weight. As is clear from FIG. 1, the haze decreases as the amount of Zn(OH) ₂ deposited increases. Especially when the amount of Zn(OH) ₂ deposited is up to 0.5 parts by weight, Zn
The haze decreases significantly as the amount of Zn(OH) ₂ increases, and the haze decreases when the amount of Zn(OH) ₂ is 0.5 parts by weight.
It is about 1/10 of the case when the amount of Zn(OH) ₂ attached is 0. Figure 2 shows the relationship between the Zn(OH) ₂ adhesion amount of Zn(OH) ₂ adhesion ZnS:Ag phosphor (including 0 adhesion amount) and cross-contamination with other luminescent component phosphors of that phosphor. This is a graph showing. There are two possible cases of cross-contamination: One is cross-contamination that adheres to the luminescent component phosphor that has already been applied (hereinafter referred to as "cross-contamination with the pre-coated luminescent component phosphor"), and the other is the one that adheres to the luminescent component phosphor that has already been applied. This is cross-contamination in which the luminescent component phosphor that is applied adheres (hereinafter referred to as "cross-contamination with the post-coated luminescent component phosphor"). Second
Figure A shows Zn(OH) ₂ attached ZnS: Ag phosphor (attached amount 0
Figure 2-B is a graph showing the relationship between the Zn(OH) ₂ adhesion amount (including Zn(OH)2) and the cross-contamination with the pre-coated ZnS:Cu,Al green-emitting component phosphor. (OH) ₂ adhesion amount of Zn(OH) ₂ on ZnS:Ag phosphor (including 0 adhesion amount) and cross-contamination with Y ₂ O ₂ S: Eu red emitting component phosphor applied after that phosphor. FIG. In Figure 2-A and B, cross-contamination (vertical axis) is represented by the values of blue output/green output and red output/blue output, respectively, and these values were measured as follows. It was done. For Figure 2-A, first, a slurry of the phosphor sample was coated onto a face plate on which stripes of ZnS:Cu, Al green light-emitting component phosphor [Zn(OH) ₂ untreated] had been formed and dried. Afterwards, development was carried out with warm water without exposure. After performing the above steps (obviously no ZnS:Ag phosphor stripes have been formed), the ZnS:Cu,Al phosphor stripes are excited with 3650 Å ultraviolet light, and the emitted light is split with a half mirror. The two lights were received in the form of a photo through green and blue ratten filters, and the respective outputs were measured to determine the value of blue output/green output. Determine the blue output/green output values for each phosphor sample,
The Zn(OH) ₂ adhesion amount of each phosphor sample was normalized as 1, and the amount of Zn(OH) ₂ adhesion (ZnS:Ag
It was plotted against (parts by weight relative to 100 parts by weight of phosphor). Regarding FIG. 2-B, first, a phosphor sample was coated with a slurry, exposed to light, and developed to form stripes. Next, Y ₂ O ₂ S:Eu red light-emitting component phosphor [Zn(OH) ₂ powder treatment] was applied as a slurry onto the face plate on which the stripes of this sample were formed, and after drying, it was coated without exposure. Developing was done with warm water. After performing the above operations (naturally Y ₂ O ₂ S: Eu
(no phosphor stripes are formed), the stripe of the sample is excited with 3650 Å ultraviolet light, the emitted light is split with a half mirror, and the two split lights are received as photomals through blue and red Ratten filters, respectively. The respective outputs were measured and the values of red output/green output were determined. Determine the red output/green output values for each phosphor sample, and
(OH) ₂ adhesion amount of 0 is normalized as 1, and the amount of Zn(OH) ₂ adhesion (ZnS:Ag phosphor
(parts by weight relative to 100 parts by weight). Figure 2 - In A and B, the larger the values of blue output/green output and red output/blue output
Pre-coating of ZnS:Ag phosphor means that there is a lot of cross-contamination with ZnS:Cu, Al phosphor and post-coating with _Y2O2S :Eu phosphor _of ZnS:Ag phosphor. do. As is clear from FIG. 2-A, it can be seen that as the amount of Zn(OH) ₂ deposited increases, the cross-contamination to the pre-applied luminescent component phosphor decreases. Especially when the amount of Zn(OH) ₂ deposited is up to 0.5 parts by weight, Zn
The decrease in cross-contamination is remarkable as the amount of (OH) ₂ attached increases. Also, as is clear from Figure 2-B, cross-contamination with the post-applied luminescent component phosphor is
Zn(OH) _2The amount of Zn deposited is 0.2 to 0.3 parts by weight.
(OH) ₂ decreases as the amount of adhesion increases, but Zn
When the amount of Zn(OH) ₂ deposited increases further, it begins to increase, and when the amount of Zn(OH) ₂ deposited is approximately 0.7 parts by weight,
It is the same as when the amount of Zn(OH) ₂ attached is 0. It is based on this knowledge that the upper limit of the amount of Zn(OH) ₂ deposited in the present invention is set to 0.7 parts by weight. As mentioned above, when the amount of Zn(OH) ₂ attached increases, cross-contamination with the post-applied light-emitting component phosphor increases.One reason for this is that the amount of Zn(OH) ₂ attached increases at a certain value. This is considered to be because the dispersibility of the phosphor deteriorates when the particle size becomes larger than this. That is, if the dispersibility deteriorates, when stripes are formed, unevenness is likely to occur on the back surface of the stripes (the surface on which post-coating is performed), and therefore cross-contamination with the post-coated light-emitting component phosphor is likely to occur. Zn(OH) ₂ adhesion
ZnS: Ag phosphor (including 0 adhesion amount) Zn(OH) ₂
FIG. 3 shows the relationship between the amount of adhesion and the dispersibility of the phosphor. In FIG. 3, dispersibility (vertical axis) is represented by sedimentation volume. This sedimentation volume value was calculated by placing 5 g of the phosphor sample in 30 g of an aqueous polyvinyl alcohol solution containing ammonium dichromate, allowing it to settle in a sedimentation tube for 24 hours, reading the volume, and converting it into a volume per 1 g. The larger the settling volume value, the worse the dispersibility. As is clear from Figure 3, the dispersibility of Zn
When the amount of Zn(OH) ₂ deposited is up to about 0.5 part by weight, it is almost the same as when the amount of Zn(OH) ₂ deposited is 0, but when the amount of Zn(OH) ₂ deposited exceeds 0.5 part by weight, Zn(OH) ₂ It can be seen that as the amount of adhesion increases, it becomes worse. As mentioned above, in the present invention, from the viewpoint of cross-contamination with the post-applied luminescent component phosphor,
Although the upper limit of the amount of Zn(OH) ₂ deposited is set to 0.7, taking this dispersibility into consideration, it is more preferable that the amount of Zn(OH) ₂ deposited is 0.5 parts by weight or less. Note that this dispersibility can be improved to some extent by adding a surfactant to the phosphor slurry or selecting the surfactant. The phosphor obtained by the present invention significantly increases the exposure sensitivity of the phosphor slurry. Figure 4 shows the amount of Zn(OH) ₂ attached on Zn(OH) 2 attached ZnS:Ag phosphor (including 0 attached amount) and the amount of Zn(OH) ₂ attached on ZnS:Ag phosphor (including 0 attached amount) and the width of the fixed width (230
2 is a graph showing the relationship between the exposure time and the exposure time required to form stripes (μm). As is clear from Figure 4, up to about 1.2 parts by weight of Zn(OH) ₂
The same stripes can be obtained with a shorter exposure time than when the amount of Zn(OH) ₂ deposited is 0. That is, when the amount of Zn(OH) ₂ deposited is about 1.2 parts by weight, which is more than 0 parts by weight, the exposure sensitivity of the phosphor slurry is improved. In particular, when the amount of Zn(OH) ₂ deposited is 0.05 to 1.0 parts by weight, the exposure sensitivity is significantly improved. Therefore, by using a phosphor slurry with improved exposure sensitivity, the exposure time can be shortened and work efficiency can be increased. Furthermore, when the exposure time is the same as when the amount of Zn(OH) ₂ deposited is 0, the amount of light from the light source can be reduced to obtain the same stripes, and the lifetime of the light source can therefore be extended. As mentioned above, it is not clear why the exposure sensitivity of a phosphor slurry using a phosphor to which an appropriate amount of Zn(OH) ₂ is attached is improved, but Zn(OH) ₂ or partially dissolved Zn ⁺⁺ increases the fluorescence. It is thought that this is because it acts as a catalyst in the body slurry and promotes photopolymerization of the photosensitive resin. Although the effects of the present invention have been explained above using the case of ZnS:Ag phosphor as an example, it has been confirmed that similar effects can be obtained in the case of other fluorescent materials for color television. It has also been confirmed that similar effects can be obtained with either a color television phosphor treated with a dispersant or a color television phosphor not treated with a dispersant. As described above, the phosphor for color television obtained by the surface treatment method of the present invention provides a color television cathode ray tube phosphor film with significantly less color mixture, and when made into a phosphor slurry, the phosphor slurry It significantly increases the exposure sensitivity of the film, and its industrial utility value is extremely large. Next, the present invention will be explained with reference to Examples. Example 1 1000 g of a green light-emitting component phosphor prepared by mixing a ZnS:Cu, Al phosphor and a ZnS:Au, Al phosphor at a weight ratio of 7:3 was suspended in 2 pure water. Add water glass (Oka Seal A manufactured by Tokyo Ohka Co., Ltd.) to this suspension.
15 g of SiO ₂ (containing 20% by weight) was added and stirred, and further 90 g of a 10% aqueous solution of zinc sulfate was added. After stirring for 10 minutes, stirring was stopped to allow the phosphor to settle, and the supernatant liquid was removed by decantation. Thereafter, the phosphor was washed twice with pure water from Step 5. In this way
Surface treatment with SiO ₂ was completed, and a phosphor with SiO ₂ attached was obtained. Next, the phosphor with SiO ₂ adhered to it obtained as described above was suspended in pure water from step 2, 28 g of a 10% aqueous solution of zinc sulfate was added to this suspension, and then suspended with an aqueous NaOH solution while stirring. The pH value of the suspension was adjusted to 10.0. After adjusting the pH, stirring was continued for an additional 5 minutes. After the stirring was stopped and the phosphor was allowed to settle, the supernatant liquid was removed by decantation, and the phosphor was further washed once with pure water from Step 5. After that, the phosphor is suctioned and dehydrated.
It was dried at 150°C for 3 hours. After drying, the phosphor was sieved through a 250 mesh sieve. Surface treatment with _SiO2 and Zn as described above
Phosphors surface-treated with (OH) ₂ have
SiO ₂ and Zn(OH) ₂ were attached, and the amount of Zn(OH) ₂ attached was 0.14 parts by weight based on 100 parts by weight of the mixed green light-emitting component phosphor. Next, a phosphor slurry was prepared in a usual manner using the phosphor obtained as described above and a normal aqueous polyvinyl alcohol solution containing ammonium dichromate, and a coating test was conducted using the obtained phosphor slurry. Color mixture (haze and cross-contamination) and exposure sensitivity (exposure time) were investigated. The results are shown in Table 1 in comparison with the case of a mixed phosphor (values in parentheses in Table 1) in which only the surface treatment with SiO ₂ was performed and no surface treatment with Zn(OH) ₂ was performed. For cross-contamination, a ZnS:Ag phosphor was used as the blue-emitting component phosphor, _{a Y2O2S} :Eu phosphor was used as the red-emitting component phosphor [all treated with Zn(OH) ₂ ], green,
Cross-contamination with post-coated ZnS:Ag blue-emitting component phosphor when blue and red-emitting component phosphors are applied in order (blue output/green output)
And cross-contamination (red output/green output) with the post-coated Y ₂ O ₂ S:Eu red light emitting component phosphor was measured. As is clear from Table 1, the phosphor whose surface has been treated with Zn(OH) ₂ has less color mixture in the phosphor film than the phosphor whose surface has not been treated with Zn(OH) ₂ , and The exposure sensitivity of body slurry was high. Example 2 ZnS: Au, Cu, Al green light emitting component phosphor 1000g
was suspended in pure water No. 2, 23.6 g of a 20% aqueous solution of zinc chloride was added to this suspension, and then the pH value of the suspension was adjusted to 8.0 with an aqueous NH ₄ OH solution while stirring. After adjusting the pH, stirring was continued for an additional 5 minutes. After the stirring was stopped and the phosphor was allowed to settle, the supernatant liquid was removed by decantation, and the phosphor was further washed twice with purified water from step 5. After that, the phosphor is suctioned and dehydrated.
It was dried at 100°C for 8 hours. After drying, the phosphor was sieved through a 250 mesh sieve. The ZnS:Au, Cu, Al phosphor surface-treated with Zn(OH) ₂ as described above contains Zn.
(OH) ₂ is attached, and the amount of Zn(OH) ₂ attached is
ZnS: 0.26 per 100 parts by weight of Au, Cu, Al phosphor
It was by weight. Next, a phosphor slurry was prepared in the same manner as in Example 1 using the phosphor obtained as described above, and a coating test was conducted using the obtained phosphor slurry.
Color mixing (haze and cross-contamination)
and the exposure sensitivity (exposure time) were investigated. The results are shown in Table 1 in comparison with the case of ZnS:Au, Cu, Al phosphors that were not subjected to the above-mentioned surface treatment with Zn(OH) ₂ (values in parentheses in Table 1). Note that cross-contamination can be prevented by using ZnS:Ag phosphor as a blue-emitting component phosphor and as a red-emitting component phosphor.
When Y ₂ O ₂ S:Eu phosphor is used [both Zn(OH) ₂ powder treated] and green, blue and red emitting component phosphors are applied in this order, the difference between post-coating and ZnS:Ag blue emitting component phosphor is Cross-contamination (blue output/green output) and cross-contamination with post-coated Y ₂ O ₂ S:Eu red emitting component phosphor (red output/green output) were measured. As is clear from Table 1, ZnS:Au, Cu, Al phosphors that have been surface-treated with Zn(OH) ₂ are different from ZnS:Au, Cu, and Al phosphors that have not been subjected to this treatment.
Less color mixing in the phosphor film than Al phosphor,
Furthermore, the exposure sensitivity of the phosphor slurry was high. Example 3 1000 g of ZnS:Ag blue light emitting component phosphor was suspended in pure water of Step 2, and SiO ₂ was added in the same manner as in Example 1.
A phosphor with SiO ₂ attached was obtained. Next, the phosphor with SiO ₂ adhered to it obtained as described above was suspended in pure water from step 2, 18.7 g of a 10% aqueous solution of zinc acetate was added to this suspension, and then, while stirring, it was mixed with an aqueous NaOH solution. The pH value of the suspension was adjusted to 9.0. After adjusting the pH, stirring was continued for an additional 5 minutes. After the stirring was stopped and the phosphor was allowed to settle, the supernatant liquid was removed by decantation, and the mixture was further washed twice with the purified water from Step 5. Thereafter, the phosphor was dehydrated by suction and dried at 200°C for 3 hours. After drying, the phosphor was sieved through a 250 mesh sieve. Surface treatment with SiO ₂ and
ZnS:Ag phosphor surface-treated with Zn(OH) ₂ has SiO ₂ and Zn(OH) ₂ attached, and Zn
The amount of (OH) ₂ deposited was 0.08 parts by weight per 100 parts by weight of the ZnS:Ag phosphor. Next, a phosphor slurry was prepared in the same manner as in Example 1 using the phosphor obtained as described above, and a coating test was conducted using the obtained phosphor slurry.
Color mixing (haze and cross-contamination)
and the exposure sensitivity (exposure time) were investigated. The results are shown in Table 1 for the case of ZnS:Ag phosphor that was subjected to the above-mentioned surface treatment with SiO ₂ but not with Zn(OH) ₂ (values in parentheses in Table 1).
A comparison is shown below. Note that cross-contamination was detected by using ZnS:Cu, Al phosphor as the green-emitting component phosphor, and using Y ₂ O ₂ S: Eu phosphor as the red-emitting component phosphor [both untreated with Zn(OH) ₂ ], and green phosphor. ,
Cross-contamination with pre-coated ZnS:Cu, Al green-emitting component phosphor (blue output/green output) and post-coated Y ₂ O ₂ S: Eu red emission when blue and red emitting component phosphors are applied in order Cross contamination (red output/blue output) with component phosphors was measured. As is clear from Table 1, the ZnS:Ag phosphor that has been surface-treated with Zn(OH) ₂ has less color mixture in the phosphor film than the ZnS:Ag phosphor that has not been subjected to this treatment, and The exposure sensitivity of body slurry was high. Example 4 ZnS: 1000 g of Ag, Al blue light-emitting phosphor was suspended in pure water of step 2, and 20% of zinc nitrate was added to this suspension.
67 g of an aqueous solution was added, and then the pH value of the suspension was adjusted to 11.0 with a KOH aqueous solution while stirring. After adjusting the pH, stirring was continued for an additional 5 minutes. After the stirring was stopped and the phosphor was allowed to settle, the supernatant liquid was removed by decantation, and the phosphor was further washed once with pure water from Step 5. Thereafter, the phosphor was dehydrated by suction and dried at 150°C for 3 hours. After drying, the phosphor was sieved through a 250 mesh sieve. Zn(OH) ₂ is attached to the ZnS:Ag, Al phosphor that has been surface-treated with Zn(OH) ₂ as described above, and the amount of Zn(OH) ₂ attached is ZnS:
The amount was 0.51 parts by weight based on 100 parts by weight of Ag, Al phosphor. Next, a phosphor slurry was prepared in the same manner as in Example 1 using the phosphor obtained as described above, and a coating test was conducted using the obtained phosphor slurry.
Mixing (haze and cross-contamination)
and the exposure sensitivity (exposure time) were investigated. The results are shown in Table 1 for the case of ZnS:Ag, Al phosphor without the surface treatment with Zn(OH) ₂ mentioned above (first
(values in parentheses). In addition, cross contamination can be prevented by using green light-emitting component phosphor.
ZnS: Cu, Al phosphor, Y ₂ O ₂ S: Eu phosphor as red emitting component phosphor [both Zn(OH) ₂
Untreated], pre-coated ZnS: Cu, Al cross-contamination with green-emitting component phosphor (blue output/green output) and post-coated Y ₂ O when green, blue and red emitting component phosphors are applied in order ₂ S：Eu
Cross contamination (red output/blue output) with the red light-emitting component phosphor was measured. As is clear from Table 1, the ZnS:Ag, Al phosphor that has been surface-treated with Zn(OH) ₂ has less color mixture in the phosphor film than the ZnS:Ag, Al phosphor that has not been subjected to this treatment. Moreover, the exposure sensitivity of the phosphor slurry was high. Example 5 Y ₂ O ₂ S: 1000 g of Eu red light emitting component phosphor
of zinc sulfate to this suspension.
Add 112g of % aqueous solution and then stir while stirring.
The pH value of the suspension was adjusted to 9.0 with an aqueous NH ₄ OH solution.
After adjusting the pH, stirring was continued for an additional 5 minutes. After stopping stirring and allowing the phosphor to settle, the supernatant liquid was removed by decantation, and the phosphor was further dissolved in 3 parts of pure water.
Washed twice with water. After that, the phosphor was dehydrated by suction and heated to 130°C.
It was dried for 6 hours. After drying, the phosphor was sieved through a 250 mesh sieve. Zn(OH) ₂ is attached to the Y ₂ O ₂ S:Eu phosphor that has been surface-treated with Zn(OH) 2 as described above, and _{the amount of Zn(OH) 2 attached} is Y _{2O2S ：} Eu
The amount was 0.57 parts by weight per 100 parts by weight of the phosphor. Next, a phosphor slurry was prepared in the same manner as in Example 1 using the phosphor obtained as described above, and a coating test was conducted using the obtained phosphor slurry.
Color mixing (haze and cross-contamination)
and the exposure sensitivity (exposure time) were investigated. The results are shown in Table 1 in comparison with the case of Y ₂ O ₂ S:Eu phosphor which was not subjected to the above-mentioned surface treatment with Zn(OH) ₂ (values in parentheses in Table 1). Note that cross-contamination is caused by using ZnS as a blue-emitting component phosphor:
Ag phosphor, ZnS as green emitting component phosphor:
Pre-coated ZnS: Cross contamination with Cu, Al green emitting component phosphor when Cu, Al phosphor [all untreated with Zn(OH) ₂ ], green, blue and red emitting component phosphor are applied in this order (Red output/Green output) and pre-coated ZnS: Cross contamination with Ag blue-emitting component phosphor (Red output/
blue color output) was measured. As is clear from Table 1, the Y ₂ O ₂ S:Eu phosphor with surface treatment with Zn(OH) ₂ is more fluorescent than the Y ₂ O ₂ S:Eu phosphor without this treatment. There was little color mixing in the film, and the exposure sensitivity of the phosphor slurry was high. Example 6 Y ₂ O ₂ S with red pigment particles: 1000 g of Eu red light-emitting phosphor was suspended in pure water of Step 2, and the surface was treated with SiO ₂ in the same manner as in Example 1.
A phosphor with SiO ₂ attached was obtained. Next, the SiO ₂ -attached phosphor obtained as described above was suspended in pure water (2), 56 g of a 10% aqueous solution of zinc sulfate was added to this suspension, and then suspended with an aqueous NaOH solution while stirring. The pH value of the suspension was adjusted to 8.0. After adjusting the pH, stirring was continued for an additional 5 minutes. After the stirring was stopped and the phosphor was allowed to settle, the supernatant liquid was removed by decantation, and the mixture was further washed twice with pure water from step 5. After that, the phosphor was dehydrated by suction and heated to 200℃ for 3 hours.
Dry for an hour. After drying, the phosphor was sieved through a 250 mesh sieve. Surface treatment with SiO ₂ and
Y ₂ O ₂ S:Eu phosphor with red pigment particles surface treated with Zn(OH) ₂ contains SiO ₂ and Zn.
(OH) ₂ was attached, and the amount of Zn(OH) ₂ attached was 0.30 parts by weight based on 100 parts by weight of Y ₂ O ₂ S:Eu phosphor with red pigment particles. Next, a phosphor slurry was prepared in the same manner as in Example 1 using the phosphor obtained as described above, and a coating test was conducted using the obtained phosphor slurry.
Color mixing (haze and cross-contamination)
and the exposure sensitivity (exposure time) were investigated. The results are shown in Table 1. In the case of a Y ₂ O ₂ S:Eu phosphor with red pigment particles, which was subjected to the above-mentioned surface treatment with SiO ₂ but not with Zn(OH) ₂ (Table 1). (values in parentheses). To prevent cross-contamination, ZnS:Ag phosphor was used as the blue-emitting component phosphor, and ZnS:Cu, Al phosphor was used as the green-emitting component phosphor [both Zn
(OH) ₂ untreated], pre-coated ZnS:Cu, when green, blue and red emitting component phosphors are applied in this order.
Cross-contamination with Al green-emitting component phosphor (red output/green output) and pre-coating
Cross contamination (red output/blue output) with ZnS:Ag blue light emitting component phosphor was measured. As is clear from Table 1, red pigment particles with Zn(OH) ₂ surface treatment were used.
The Y ₂ O ₂ S:Eu phosphor has less color mixing in the phosphor film than the Y ₂ O ₂ S:Eu phosphor that does not undergo this treatment and has red pigment particles, and the exposure sensitivity of the phosphor slurry is high. Ta.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the amount of Zn(OH) ₂ attached and the haze of the Zn(OH) ₂ attached ZnS:Ag phosphor (including the amount of 0 attached). Figure 2 - A is Zn(OH) ₂
Adhered ZnS: Zn of Ag phosphor (including 0 adhesion amount)
(OH) ₂ deposition amount and its phosphor pre-coating ZnS:Cu,
It is a graph showing the relationship of cross-contamination with Al green light-emitting component phosphor. Figure 2-B
Zn(OH) ₂ adhesion ZnS: Ag phosphor (including 0 adhesion amount) Zn(OH) ₂ adhesion amount and subsequent application of the phosphor
Y ₂ O ₂ S: is a graph showing the relationship of cross contamination with Eu red light emitting component phosphor. Third
The figure is a graph showing the relationship between the amount of Zn(OH) ₂ attached to a Zn(OH) ₂ attached ZnS:Ag phosphor (including the amount of 0 attached) and the dispersibility of the phosphor. Figure 4 shows Zn
(OH) ₂ attached ZnS: Ag phosphor (including 0 attached amount)
It is a graph showing the relationship between the amount of Zn(OH) ₂ deposited and the exposure time when forming stripes of a constant width (230 μm) using a phosphor slurry using the phosphor.

Claims (1)

[Claims] 1. A method characterized by adding an alkali to a phosphor suspension containing a phosphor and zinc ions to adjust the pH of the suspension to 7.5 to 11, and then separating the phosphor from the suspension. A surface treatment method for phosphors. 2 The phosphor suspension containing the phosphor and zinc ions contains at least one selected from the group consisting of zinc sulfate, zinc acetate, zinc nitrate, and zinc halide (ZnX ₂ , where X is a halogen excluding fluorine). 2. The surface treatment method for a phosphor according to claim 1, comprising an aqueous solution containing a water-soluble zinc compound and a phosphor dispersed in the aqueous solution. 3. Claim 1 or 2, wherein the alkali is an aqueous solution of at least one compound selected from the group consisting of sodium hydroxide, potassium hydroxide, and ammonium hydroxide. surface treatment method for phosphors. 4. The method for surface treatment of a phosphor according to any one of claims 1 to 3, characterized in that a dispersant is also used in the surface treatment. 5. The method for surface treatment of a phosphor according to claim 4, wherein the dispersant is silicon dioxide. 6. The method for surface treatment of a phosphor according to claim 4 or 5, wherein the phosphor suspension is prepared after the surface of the phosphor is treated with the dispersant.