JPS6389890A - Black based particle and display device containing black based particle - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to spacer particles for display devices and display devices containing these particles, and more particularly to spacer particles for display devices with a sharp particle size distribution that can be manufactured by a specific method. and a display device including the particles as a spacer.

Technical background of the invention and its problems Liquid crystal display devices are widely used as display devices for watches, calculators, wall-mounted televisions, and the like.

This liquid crystal display device is a display device that uses liquid crystal, which changes the polarization direction by changing the arrangement of molecules simply by applying a slight voltage, and usually has a structure in which a liquid crystal layer is sandwiched between two electrodes. are doing.

In such a liquid crystal display device, it is desirable that the thickness of the liquid crystal layer be as thin as possible, and it is also desired that there be no variation in the thickness of the liquid crystal layer. If there are variations in the thickness of the liquid crystal layer, the electric field strength applied to the liquid crystal layer will be partially non-uniform, which will cause the contrast ratio of the image to vary from place to place, causing unevenness in the image. In addition, the response speed of a liquid crystal to an input signal changes depending on the thickness of the liquid crystal layer and the electric field strength, but if the thickness of the liquid crystal layer is uneven, a difference in response speed will occur and it will become clearer. You will not be able to obtain a clear image.

For this reason, in liquid crystal display devices, a thin and uniform liquid crystal layer is formed between the two electrodes by interposing a spacer made of a thin insulator between the two electrodes and filling the space with liquid crystal.

Spacers used in the above-mentioned liquid crystal display devices include aluminum oxide for abrasives classified into 2 to 10 μm, glass fibers with a diameter of 2 to 10 μm, and 50 μm in diameter.
Those cut into lengths of ~100 μm, or synthetic a-fats such as benzoguanamine shaped into spheres of 2 to 10 μm have been used.

Liquid crystal display devices using such conventionally known spacers do not pose any major problems when the size is small, but when the size becomes large, the following problems occur: There is.

(a) It is necessary to slightly change the thickness of the liquid crystal layer depending on the type of liquid crystal used, but it is not possible to control the shape of the spacer to accommodate this subtle change in the thickness of the liquid crystal layer. .

(b) The particle size distribution of the spacer particles is large, making it impossible to provide a liquid crystal layer with a uniform thickness, which may result in uneven images or color tone abnormalities.

(C) When using ferroelectric liquid crystal, it is necessary to keep the thickness of the liquid crystal layer to about 1 to 2 μm, but a spacer that can adjust the thickness of the liquid crystal layer to such a thickness is required. does not exist.

(d) The spacer particles in the liquid crystal layer aggregate and the spacer is visible in the displayed image, or the length of the long sleeve is 10 to 50 μm.
With this spacer, the spacer itself may be visible in the displayed image.

(e) Since the spacer particles are not spherical, the spacer may damage the transparent electrode, resulting in a defective display device.

(f) When the spacer is made of resin, it is easily deformed by heating or pressure, and a uniform thickness of the liquid crystal layer cannot be provided.

(g) If the spacer is made of white particles, the resulting image may be inferior in terms of contrast compared to the case where black particles are used as the spacer.

However, at present, there are no known black spacer particles that can be used in display devices.

This is because, for example, if you try to use black pigment particles as spacer particles, it is extremely difficult to adjust the particles uniformly, and if you try to use colored resin particles as spacer particles, it will be similar to the above. This is because problems may arise.

The present inventors have conducted intensive studies to solve the problems associated with conventionally known spacer particles for display devices, and have found that certain black particles are excellent as particles for spacers, and that specific black particles are excellent as spacer particles. The inventors have discovered that black particles with a sharp particle size distribution obtained by the method described above can be used as spacers for display devices, and have completed the present invention.

The present invention attempts to solve the problems associated with the conventional technology as described above, and is capable of responding to subtle changes in thickness and achieving uniform thickness. and a liquid crystal display device containing the black spacer particles. The purpose is

Summary of the Invention The black spacer particles for display devices according to the present invention comply with the JIS
The Y value is 10% or less in the XYZ system of colors defined in accordance with Z 8701, and the particle size is 0.1 to 10 μm.
It is characterized by being

Further, in the display device such as the liquid crystal display device according to the present invention, a metal alkoxide is added to a water-alcohol dispersion liquid in which a metal oxide or metal hydroxide is separated as a sheet while keeping the dispersion alkaline. The blackish particles obtained by hydrolyzing the metal alkoxide decomposition product on the sheet to cause particle growth, and then heat-treating the particles separated from the dispersion at a temperature of 250 ° C. or higher. , as a spacer.

The spacer particles for display devices according to the present invention comply with JIS Z
8701 is an XYZ system that has a constant uniformity, and is very black with a Y value of 10% or less, and has a sharp particle size distribution with particles ranging from 0.1 to 10μ.

The display device according to the present invention includes, as a spacer, black particles that are 1q-sized by a specific method, and the spacer has a sharp particle size distribution, and the particle size can be controlled to an arbitrary size. Moreover, since the particles rarely aggregate with each other, the display has excellent characteristics such that it can respond to subtle changes in thickness, has a uniform thickness, and the spacer particles are not visible from the outside. A device is obtained.

Further, since the black spacer particles described above are spherical, they do not damage the transparent electrode and do not undergo deformation due to heat or pressure. Furthermore, since metal alkoxide is used as a raw material, a highly pure spacer can be obtained.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The black spacer particles for a display device according to the present invention and the display device including the black spacer particles will be specifically described below.

The black spacer particles for display devices according to the present invention comply with JIS
It is an XYZ color system defined by Z 8701, and the Y value corresponding to the brightness of the color is 10% or less, and it has excellent blackness. Moreover, these black spacer particles have a sharp particle size distribution as described below, and the particle diameter is precisely controlled to any size within the range of 0.1 to 10 μm, and the particles do not aggregate with each other. It has a spherical shape and is not deformed by heat or pressure.

Furthermore, these black spacer particles have excellent insulation properties and are chemically highly pure since metal alkoxide is used as a raw material.

On the other hand, for example, black pigment particles or colored organic resins cannot be used as black spacer particles for display devices. This is because these particles have large variations in particle size distribution or are deformed by heat or pressure.

The display device according to the present invention is characterized in that it includes blackish particles manufactured by a specific method as a spacer. A method for producing the black spacer particles will be explained.

First, a water-alcohol dispersion in which a metal oxide or metal hydroxide is dispersed in the form of a sheet is prepared. The sheets dispersed in the water-alcohol dispersion are metal oxide particles or metal hydroxide particles, but other particles with uniform particle sizes may be used depending on the case. The particles used as the sheet as described above preferably have a particle size as uniform as possible of about 0.05 to 9 μm.

The water-alcohol dispersion in which such a sheet is dispersed may be obtained by adding the sheet to a water-alcohol mixed solution or by forming the sheet in the water-alcohol dispersion. Among these, a water-alcohol dispersion in which a sheet obtained by hydrolyzing a metal alkoxide in a water-alcohol dispersion is dispersed is preferably used. The sheet production method is, for example, powder and powder metallurgy - Otsu 2 -
2(4), 19-24 (1976) or JO
tJrllalcolloid &Interface
Sci, 26.62-69 (1968).

In this way, a water-alcohol dispersion in which metal oxide particles or metal hydroxide particles are dispersed in the form of sheets is obtained. is added to form a stabilized dispersion (hereinafter sometimes referred to as heel sol). If the dispersion is not stabilized by adding an alkali, the sheet particles may aggregate and precipitate. When the sheets agglomerate, metal alkoxide decomposition products also adhere to the joints (necks) of the agglomerated particles, making it impossible to obtain particles with a uniform particle size.

The alkali added to stabilize the dispersion is as follows:
Ammonia gas, aqueous ammonia, alkali metal hydroxides such as sodium hydroxide, quaternary ammonium salts, amines, etc. may be used alone or in combination.

The alcohol concentration in the water-alcohol dispersion in which the sheet is dispersed is preferably 35 to 97% by weight.

The alcohols used here include methanol, ethanol, n-propanol, isopropanol, n-propanol,
Lower alcohols such as butyl alcohol and isobutyl alcohol are used. Moreover, a mixed solvent of these lower alcohols can also be used.

In addition to water and alcohol, other organic solvents can also be used as the water-alcohol dispersion. As such an organic solvent, one is used that has good compatibility with water and alcohol, and also has good compatibility with metal alkoxide.

The concentration of the sheet in the water-alcohol dispersion is preferably 0.05 to 20.0% by weight in terms of oxide concentration. If the equivalent oxide concentration of the sheet is less than 0.05 F, a new sheet may be generated in the subsequent step of attaching metal alkoxide decomposition products to the sheet.
This is not preferable because the particle size distribution of the obtained particles becomes broad.

On the other hand, if the oxide concentration of the sheet exceeds 20.0% by weight, the metal alkoxide decomposition product will aggregate with each other during the process of adhering to the sheet, which is not preferable.

Next, a metal alkoxide is added to the heel sol, which is a water-alcohol dispersion in which the alkali-stabilized sheet obtained as described above is dispersed, while keeping the heel sol alkaline, and hydrolyzed. A metal alkoxide decomposition product is deposited on the sheet to grow sheet particles.

As the metal alkoxide, any metal alkoxide can be used as long as it can form an alkoxide. The number of carbon atoms in the ester group forming the alkoxide is preferably about 1 to 7, preferably about 1 to 4. Such metal alkoxides may be used after being diluted with alcohol or the like, or may be used as a undiluted solution.

When adding the metal alkoxide to the dispersion, it is preferable to add a water-alcohol mixed solution together with the metal alkoxide. It is preferable that these metal alkoxides and water-alcohol mixed solution are gradually added to the heel sol.

When a metal alkoxide is added to Healsol, the metal alkoxide begins to hydrolyze, and at this time, the pH of the solution rapidly increases.
tt changes. If the heel sol liquid is no longer alkaline as described above, the sheets may aggregate or new sheets may be generated, which is not preferable because the particle size distribution of the final particles becomes broad. Therefore, when adding the metal alkoxide, the heel sol is kept alkaline. pH of Healsol
is preferably 10 to 13. In order to keep the heel sol alkaline, it is sufficient to add alkali to the heel sol. Specifically, as the alkali added,
Asimonia gas, aqueous ammonia, amines, alkali metal hydroxides, and quaternary ammonium salts may be used alone or in combination.

The temperature at which the metal alkoxide is hydrolyzed is not particularly limited, but when a temperature higher than the boiling point of water or alcohol is used, it is preferable to pressurize the solution so that it can maintain a liquid phase. However, carrying out the decomposition reaction of the metal alkoxide above the critical temperature of alcohol or the like present in the reaction system may change the composition ratio in the liquid phase, so it is preferable to carry out the decomposition reaction below the critical temperature.

As described above, sheet particles are grown by adhering metal alkoxide decomposition products onto the sheet, but the concentration of the grown particles in the reaction system is 0.05 to 2 in terms of oxide concentration.
It is preferably 0.0% by weight, preferably 0.05 to 15.0% by weight. If the concentration of particles is less than 0.05 weight percent, productivity will be poor and a large amount of alcohol will be required, resulting in poor economic efficiency.On the other hand, if the particle concentration exceeds 20% by weight, particles will increase during the particle growth of the sheet. This is not preferable because it causes aggregation between particles and the particle size distribution of the particles becomes broad.

When depositing the metal alkoxide decomposition product on the sheet, the alcohol concentration in the reaction system is preferably 35 to 97% by weight.

If the alcohol concentration is less than 35% by weight, it will have poor compatibility with the metal alkoxide to be added and will form an emulsion.
This is not preferable because the sheet may aggregate or an amorphous product that is not spherical may be obtained.
If it exceeds % by weight, the rate of hydrolysis of the metal alkoxide becomes too slow, which is not preferable. The alcohol concentration in the reaction system can be adjusted by adding water and alcohol together with the metal alkoxide into the reaction system,
Alcohol is used at a ratio of O14 to 1.1 mole to alkoxide, and water is used at a ratio of 2.0 to 24 mole to alkoxide.
．． It is preferable that it is added in a proportion of 0 mol.

The particles thus obtained, dispersed in the water-alcohol dispersion medium, are spherical, have a particle diameter of about 0.1 to 10μ, and have a sharp particle size distribution (±σ≦0.5). Dispersed in a dispersion medium. Furthermore, according to the method for producing particles as described above, the particle size of the obtained particles is set to 0.1 to 1.
It can be easily controlled to any value within 0μ. The concentration of particles in the dispersion medium based on oxides is 0.05~
This is 20.0% by weight, which can be significantly higher than in conventional methods of producing particles using metal alkoxides. Therefore, it is possible to increase the production efficiency of the particles and also to reduce the production cost.

In order to further increase the stability of the particles dispersed in the dispersion obtained in this way, if a stabilizer such as an alkali is added to the dispersion obtained and aging is performed, the dispersion will remain stable for a long period of time. The particles inside do not aggregate.

Next, the dispersion obtained as described above is dried according to a conventional method to obtain spherical particles with good dispersibility. The particles obtained at this stage are still white in color. The particles are then heated to 250°C or higher, preferably 250 to 1000°C.
When heat-treated in an air atmosphere or an inert gas atmosphere at a temperature of , the white particles change to black, and black particles with good dispersibility are obtained.

The reason why white particles change to black particles by heat treatment at a temperature of 250° C. or higher is considered to be due to the following reasons. In other words, organic substances such as unreacted metal alkoxides are present inside the particles before heat treatment, and when these unreacted organic substances such as metal alkoxides are heated to a temperature of 250°C or higher and decomposed or carbonized, , the particles probably turn black.

As mentioned above, the heat treatment temperature for the white particles is 250°C or higher, preferably 250 to 1000°C. However, if the heat treatment temperature is lower than 250°C, the white particles will be blackened; This is not preferable because it takes a long time for the heat treatment to occur. On the other hand, if the heat treatment temperature exceeds 1000'C, sintering between particles may occur, which is not preferable.

Generally, when the particle size of white particles is small, 2
Blackening occurs by heat treatment at a relatively low temperature in the temperature range of 50 to 1000'C, but as the particle size increases, heat treatment at a relatively high temperature is required.

Further, in the present invention, when adding the metal alkoxide to the water-alcohol dispersion in which the sheet is dispersed, an organic substance that is dissolved or dispersed in the water-alcohol dispersion is added, and this organic substance is By depositing the particles together with a metal alkoxide decomposition product on a sheet and then heat-treating the resulting particles to a temperature of 250° C. or higher, the color tone of the resulting black particles can be roughly blackened. Alternatively, before heat-treating the white particles obtained by drying the dispersion, the white particles may be impregnated with a solution of an organic substance to attach the organic substance to the particles, and then heat-treated. The color tone of the black particles can be further blackened.

In order to assemble a display device such as a liquid crystal display device using the thus obtained dispersed black particles as a spacer, a conventionally known method can be applied as is.

In the present invention, a display device is provided by using the particles manufactured as described above as a spacer, but the display device can be used in addition to a liquid crystal display device, an erectrochromic display (EDC), a plasma display (PD
P), used in liquid crystal printers, touch panels, light modulation elements, etc.

Effects of the Invention The spacer particles for display devices according to the present invention comply with JIS Z
It is an XYZ system defined by 8701, has a Y value of 10% or less, is very black, and has particles of 0.1 to 10 μm.
The particle size distribution is sharp.

The display device according to the present invention includes black particles obtained by a specific method as a spacer, and the spacer
! - It has a narrow particle size distribution, and it is possible to control the particle diameter to any desired size.Moreover, the particles rarely aggregate with each other, so it can respond to strange changes in thickness, and A display device can be obtained that has a uniform thickness and has excellent properties in that the spacer particles are not visible from the outside.

Further, since the black spacer particles described above are spherical, they do not damage the transparent electrode and do not undergo deformation due to heat or pressure. Since a metal alkoxide is used as a raw material, it also has the effect of producing a highly pure spacer.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

A mixed solution of 487 g of Inuzinho-Yuethyl alcohol and 3899 g of water was kept at 35° C. while stirring, and 71.1 g of ammonia gas was dissolved in this mixed solution. Add 28% ethyl silicate to this mixture17. = 1, then continued stirring for 2 hours and added S
A cloudy white liquid was obtained in which sheet particles corresponding to 0.5% by weight in terms of iO2 were dispersed.

Immediately, 3.33 g of an aqueous solution in which 0.03 g of NaOH was dissolved was added to this cloudy liquid to obtain a heel sol (A>) in which sheet particles were dispersed in a water-alcohol dispersion.

A mixture of 455 g of ethyl alcohol and 886 g of water and 570 g of 28% ethyl silicate was added to 91 of the obtained heel sol (A) while stirring and keeping p[1 at 11.5 while controlling p[1 to 11.5. At the same time, it was gradually added over 19 hours. After adding the entire amount, 103 g of an aqueous solution in which NaOH19 was dissolved was added, and the mixture was heated to 70'C and held for 2 hours to obtain a dispersion (1).

This dispersion (I>) was dried at 110° C. to obtain white powder particles.

Next, the white particles thus obtained were heat-treated at 350° C. for 3 hours in an air atmosphere, yielding 1q of black spacer particles for a display device.

The shape of the black particles was examined using a scanning electron microscope (SEM), and a photograph (200x magnification) is shown in FIG.

Next, sealing resin (manufactured by Mitsui Toatsu, epoxy resin) 1
00g, black powder particles 1 obtained as above
An ink composition was prepared by dispersing g. The obtained ink composition was printed with a screen printer on the periphery of the alignment film of a laminate in which a transparent electrode and an alignment film were formed on a 2 cm x 2 cm polished glass substrate for a liquid crystal display device, thereby producing a large-sized liquid crystal display device. The board for this is 1q.

Next, ethyl alcohol (EtOH) 1.1! 0.01 g of the black powder particles obtained as described above was dispersed in the solution, and this dispersion was used to coat a large liquid crystal display device substrate placed in a spray chamber maintained at a room temperature of 60° C. and a humidity of 3%. The sealing resin was sprayed onto the areas where it was not installed. After pre-drying this at 90°C for 30 minutes, this was bonded to another large liquid crystal display substrate comprising a glass substrate with transparent electrodes and an alignment film, and heated at 3 Ky/d. The resin was cured by heating at 150'C for 11 hours under pressure to produce 100 cells for large-sized liquid crystal display devices.

A liquid crystal as described below was injected into the portion of the cell for a large-sized liquid crystal display obtained in this way, where the sealing resin was not provided, to obtain a large-sized liquid crystal display.

Example 2 Dispersion (1) 1149 obtained in Example 1 was stirred for 35 minutes.
℃, add 63y of ethyl alcohol and 51g of water, and control the pH to 11.5 with ammonia gas.
A mixture of 638 g of ethyl alcohol and 814 g of water and 325 g of 28% ethyl silicate were simultaneously added gradually over 19 hours. After adding the entire amount, NaOH0,
65 g3 of an aqueous solution in which 7 g was dissolved was added, and the mixture was heated to 70° C. and held for 2 hours to obtain a heel sol (B). 94.6 g of this heel sol (B) was kept at 65°C with stirring, and 116 g of ethyl alcohol and 95 g of water were added thereto. While controlling the pH to 11.5 with ammonia gas, a mixture of 307 g of ethyl alcohol and 438 J of water and 28% Ethyl silicate 207! ? was simultaneously added gradually over 19 hours.

After adding the entire amount, 65 g of an aqueous solution containing 0.7 g of NaOH dissolved in the liquid was added, and this was heated to 70°C and held for 2 hours to obtain a dispersion (If>. This dispersion was heated to (II> at 110°C).
The mixture was dried to obtain white powder particles.

Next, the thus jqed white particles were heat-treated at 750° C. for 3 hours in a nitrogen atmosphere to obtain black particles.

Next, an ink composition was prepared by dispersing 1.5 g of the black powder particles obtained above in 10 g of sealing resin, and 0.5 g of the black powder particles obtained in the above manner was dispersed in 1 g of ethyl alcohol.
Example 1 except that a dispersion liquid was prepared by dispersing 05g of
A large liquid crystal display device was created using the same method.

Large population - dispersion (II) obtained in Example 2 1126! J was kept at 65°C with stirring, and this dispersion (155 g of ethyl alcohol and 127 g of water was added to I [> and t with ammonia gas)
A mixture of 164 g of ethyl alcohol and 275 g of water and 156 g of 28% ethyl silicate were simultaneously added gradually over 19 hours while controlling the temperature to 11.5. After adding the entire amount, 65 g of an aqueous solution in which Na0H0,1 was dissolved in the solution was added, and this was heated to 70° C. and held for 2 hours to obtain Heal Sol (C).

1324 t of this Heal Sol (C) was kept at 65°C with stirring, 185 g of ethyl alcohol and 1519 g of water were added, and while controlling the pH to 11.5 with ammonia gas, a mixture of 93 g of ethyl alcohol and 150 g of water and 2.
82 g of 8% ethyl silicate was simultaneously added slowly over 19 hours.

After the addition of (6), an aqueous solution 589 in which 080.6 g of Na was dissolved was added, and this was heated to 70° C. and held for 2 hours to obtain a dispersion (nI). This dispersion (I[I) was added to 11
It was dried at 0°C to obtain white powder particles.

Next, the thus obtained white particles were heat-treated at 750° C. for 3 hours in an air atmosphere, and black particles were obtained.

Next, an ink composition was prepared by dispersing 1.89 g of the black powder particles obtained as described above in 100 g of sealing resin, and 0.8 g of the black powder particles obtained in the above manner was dispersed in 1 g of ethyl alcohol.
A large-sized liquid crystal display device was produced in the same manner as in Example 1, except that a dispersion liquid was prepared by dispersing No. 19.

Example 4 1509 g of ethyl alcohol and 3007 g of water were added to Heal Sol (A) obtained in Example 1 while stirring and keeping the temperature at 35°C and controlling the pH to 11.5 with ammonia gas.
and 28% ethyl silicate 2268!7
was simultaneously added gradually over 19 hours. After adding the entire amount,
Aqueous solution 2049 in which Na0H2CJ was dissolved was added to the liquid, and this was heated to 70°C and held for 2 hours to form a dispersion (IV).
I got it. This dispersion (IV) was dried at 110°C to obtain white powder particles.

Next, the white particles thus obtained were heat-treated at 300° C. for 1 hour in a nitrogen atmosphere to obtain black particles.

Next, an ink composition was prepared by dispersing 0.5 g of the black powder particles obtained as described above in a sealing resin "+oog", and 0.5 g of black powder particles obtained in the above manner was dispersed in ethyl alcohol 19.
．． Example 1 except that a dispersion liquid was prepared by dispersing No. 19.
A large liquid crystal display device was created using the same method.

A large liquid crystal display device was fabricated in the same manner as in Example 1, except that conventionally known spacers as shown in Table 1 were used.

The characteristics of the large liquid crystal display device obtained as described above were evaluated by the following method.

■The center, right side, and left side of the cell were cut using a diamond cutter, and the thickness of the liquid crystal layer was measured using an electron microscope.

■The presence or absence of spacer coarse particles (agglomerated particles) in the image section was visually observed, and those in which even one coarse particle was visually observed were judged to be defective.

In Example 1, Comparative Example 1, and Comparative Example 4, Smc* liquid crystal (ferroelectric liquid crystal, manufactured by Merck & Co., Ltd.) was used, and in Example 2, Comparative Example 2, and Comparative Example 5, SBE liquid crystal (manufactured by Merck & Co., Ltd.) was used. In Example 3, Comparative Example 3, and Comparative Example 6, TN liquid crystal (manufactured by Merck & Co., Ltd.) was injected. Table 2 shows the operating conditions of the obtained large-sized liquid crystal display device.

The Y values (values expressed in accordance with JIS Z8701) of the black particles and white particles used in each Example and Comparative Example were measured as follows.

S&M color computer: Using 5M4-C1-1 type (manufactured by Suga Test Instruments), particles were placed in a cylindrical gel and tilted at 45°.
Measured by reflection method.

From Table 1, it can be seen that the black spacer particles for display devices according to the present invention have a diameter ranging from 0.1 to 10 μm, a sharp particle size distribution, and an excellent black color.

Furthermore, from Table 2, it can be seen that the display device containing the above-mentioned black particles as a liquid crystal spacer has small variations in the thickness of the liquid crystal layer, good operating efficiency, and excellent display performance.

[Brief explanation of the drawing]

FIG. 1 is a scanning electron micrograph (7500x magnification) showing the shape of particles obtained by the present invention.

Claims (1)

[Scope of Claims] 1) Black spacer particles for display devices having a Y value of 10% or less in the XYZ system of colors defined by JIS Z 8701 and a particle size of 0.1 to 10 μm. 2) A metal alkoxide is added to a water-alcohol dispersion in which a metal oxide or metal hydroxide is dispersed in the form of a sheet while keeping the dispersion alkaline, and the metal alkoxide is hydrolyzed to form a decomposed metal alkoxide on the sheet. A display device containing black particles as spacers obtained by attaching a substance to cause particle growth and then heat-treating particles separated from a dispersion at a temperature of 250° C. or higher.