JP2011065000A - Near-infrared absorption filter for plasma display panel, method of manufacturing the same, and the plasma display panel - Google Patents

Abstract

The present invention provides a near-infrared absorption filter for plasma display panel (PDP) that maintains high visible light transmittance and near-infrared absorptivity and also has excellent heat and moisture resistance, a method for producing the same, and a PDP using the filter.
In a near-infrared absorption filter for PDP having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed, the fine particles have a hexagonal crystal structure in which zinc represented by ZnxMyWOz is dissolved. It is composed of composite tungsten oxide B fine particles, and the lattice constant ratio c / a is 1.027300 to 1.027700 larger than the lattice constant ratio c / a of composite tungsten oxide A shown by MyWOz, or lithium shown by LixMyWOz Is composed of fine particles of a composite tungsten oxide B having a hexagonal crystal structure in which a solid solution is formed, and the lattice constant ratio c / a is larger than the lattice constant ratio c / a of the composite tungsten oxide A and is 1.027300 to 1.029000. It is characterized by being.
[Selection] Figure 1

Description

  The present invention relates to an optical filter for a plasma display panel (hereinafter may be abbreviated as PDP) and a method for manufacturing the same, and in particular, high near-infrared absorption with respect to the near-infrared emitted from the plasma display body toward the front surface of the PDP screen. The present invention relates to a near-infrared absorbing filter for PDP having excellent moisture and heat resistance characteristics while maintaining the characteristics, a manufacturing method thereof, and a PDP using the filter.

  In recent years, PDPs have attracted attention as displays become larger and thinner. A general configuration of this PDP will be described with reference to the drawings. FIG. 1 is an enlarged cross-sectional view showing an outline of an AC type (AC type) PDP light emitting unit. In FIG. 1, reference numeral 11 denotes a front glass substrate (front cover plate), and display electrodes 12 are formed on the front glass substrate 11. Furthermore, the front glass substrate 11 on which the display electrodes 12 are formed is covered with a dielectric glass layer 13 and a protective layer 14 made of magnesium oxide (MgO) (see, for example, Patent Document 1). Reference numeral 15 denotes a rear glass substrate (back plate). On the rear glass substrate 15, address electrodes 16, partition walls 17, and a phosphor layer 18 are provided. Reference numeral 19 encloses a discharge gas. It is a discharge space.

  The light emission principle of the PDP is that a voltage is applied between the display electrode 12 and the address electrode 16 to discharge in the discharge space 19 and excite the mixed gas of xenon and neon introduced into the discharge space. Then, vacuum ultraviolet rays are radiated, and the phosphor layers 18 emitting red, green and blue fluorescence are emitted by the vacuum ultraviolet rays, respectively, to enable color display.

  However, xenon gas also generates near infrared rays in addition to the vacuum ultraviolet rays, and a part of the near infrared rays is emitted forward of the PDP. In particular, near-infrared rays having a wavelength range of 800 nm to 1100 nm cause problems such as malfunctioning of cordless phones and remote controls of home appliances, and adverse effects on transmission optical communication. For this reason, the near-infrared shielding process is performed on the front surface of the PDP for the purpose of preventing the malfunction and the like.

  These near-infrared shielding processes are performed by providing a near-infrared absorbing material as a filter on the front surface of the PDP. The near-infrared absorbing material has a visible light region (wavelength region) so as not to adversely affect the brightness of the PDP. , Approximately 380 nm to 780 nm) is sufficiently transmitted, and near infrared light having a wavelength range of 800 nm to 1100 nm is required to be shielded. Conventionally, as a PDP filter that absorbs near-infrared rays, a filter in which many kinds of organic dyes or metal complexes are combined or applied in multiple layers (see Patent Document 2, Patent Document 3, etc.) has been proposed.

  When an organic compound or a metal complex is used as a filter, a method of coating a base material on the surface of a PDP with a solution obtained by dissolving the organic compound or the metal complex in a solvent is generally performed. Here, as near-infrared absorbing materials such as organic compounds and metal complexes, diimonium compounds, aminium compounds, phthalocyanine compounds, organometallic complexes, cyanine compounds, azo compounds, polymethine compounds, quinone compounds, diphenylmethane compounds Compounds, triphenylmethane compounds, etc., but these have low resistance to heat and light and are likely to deteriorate over time, so when these organic compounds and metal complexes are used alone, the performance is prolonged. There was a problem that it was difficult to hold.

  Therefore, in order to effectively shield near infrared rays using an organic compound or a metal complex, it is necessary to coexist two or more substances, but in this case, each substance reacts to deteriorate the characteristics, The metal complex has a problem of poor solubility in a solvent and does not sufficiently dissolve. In order to deal with this problem, there is a method in which each solution is prepared in consideration of the solubility of each near-infrared absorbing material, and each solution is applied again. In this case, it is necessary to apply each solution again. There was a problem that it took time and effort.

  In order to solve the above-mentioned problems, the present applicant has made use of tungsten oxide (general formula WOz) that can transmit visible light and largely shield near-infrared as a near-infrared absorbing material, and composite tungsten oxide (general). Inorganic material fine particles of the formula MyWOz (see Patent Document 4) have already been proposed. By using these inorganic material fine particles for the near infrared ray absorbing material, the near infrared ray absorption is greatly improved, and the resistance to wet heat can be improved as compared with the case of using the above-mentioned organic compound or metal complex.

  However, further improvement in performance has been required for resistance to wet heat.

JP-A-5-342991 JP 2001-228324 A JP 2001-133624 A JP 2006-154516 A

  The present invention has been made paying attention to such problems, and the subject is a PDP that exhibits excellent resistance to wet heat while maintaining high visible high transmittance and near infrared absorption. The present invention provides a near-infrared absorption filter for use and a manufacturing method thereof, and also provides a PDP using a near-infrared absorption filter for PDP.

  Therefore, as a result of continuous researches by the present inventors in order to solve the above-mentioned problems, the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg). One or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) In general formula ZnxMyWOz produced by reacting a compound containing zinc element such as zinc carbonate with a compound tungsten oxide A to distinguish it from a compound tungsten oxide in which Zn is dissolved, wherein Zn is zinc and M is One or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0 And a composite tungsten oxide having a hexagonal crystal structure in which zinc represented by (referred to as composite tungsten oxide B to distinguish from the composite tungsten oxide A), and the composite tungsten oxide A, LixMyWOz produced by reacting a compound having a lithium element such as lithium carbonate (where Li is lithium, M is one selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg) The above elements, W is tungsten, O is oxygen, and lithium represented by 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) is a solid solution. The composite tungsten oxide having a hexagonal crystal structure (referred to as composite tungsten oxide B) exhibits excellent moisture and heat resistance while maintaining high visible light transmittance and near infrared absorption. And a near-infrared absorbing filter for plasma display panels having a near-infrared absorbing material fine particle dispersion in which composite tungsten oxide B fine particles represented by the general formulas ZnxMyWOz and LixMyWOz are dispersed. The inventors have found that they exhibit excellent moisture and heat resistance while maintaining light transmittance and near infrared absorption. The present invention has been completed based on such technical findings.

That is, the invention according to claim 1
In a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
The near-infrared absorbing material fine particles have a general formula ZnxMyWOz (where Zn is zinc, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten) , O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0), which is a hexagonal crystal structure in which zinc is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg). 1 or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Greater than / a and the value is 1.027300 to 1.027700 And butterfly,
The invention according to claim 2
In the near-infrared absorption filter for a plasma display panel according to the invention of claim 1,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) and a mixture of the compound having a zinc element and a compound having a zinc element in a reducing gas atmosphere, an inert gas atmosphere, or a reducing gas. The fine particles of the composite tungsten oxide B according to claim 1, which are represented by the general formula ZnxMyWOz, are obtained by heat treatment in a mixed atmosphere of oxygen and an inert gas.

The invention according to claim 3
In a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
The near-infrared absorbing material fine particles have a general formula LixMyWOz (where Li is lithium, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, and W is tungsten. , O is oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) and a hexagonal crystal structure in which lithium is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg). 1 or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Larger than / a, and the value is 1.027300 to 1.029000 Features a Rukoto,
The invention according to claim 4
In the near-infrared absorption filter for a plasma display panel according to the invention of claim 3,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) and a mixture of a compound having a lithium element and a compound having a lithium element is calcined in the atmosphere or in an inert gas atmosphere, and then reduced gas. The fine particles of the composite tungsten oxide B according to claim 3, which are heat-treated in an atmosphere or a mixed atmosphere of a reducing gas and an inert gas, are represented by the general formula LixMyWOz. .

Next, the invention according to claim 5 is:
In the near infrared absorption filter for a plasma display panel according to any one of claims 1 to 4,
The near-infrared absorbing material fine particle dispersion is a diimonium compound, an aminium compound, a phthalocyanine compound, an organometallic complex, a cyanine compound, an azo compound, a polymethine compound, a quinone compound, a diphenylmethane compound, or a triphenylmethane compound. Characterized in that it contains one or more organic compounds selected from
The invention according to claim 6
In the near-infrared absorbing filter for a plasma display panel according to any one of claims 1 to 5,
The near-infrared absorbing material fine particles according to claim 1 or 3 or the near-infrared absorbing material fine particles, the organic compound according to claim 5, a binder component, and / or a surface of a substrate constituting a near-infrared absorbing filter for a plasma display panel. The near-infrared absorbing material fine particle dispersion is constituted by a coating film formed by coating a coating solution containing an adhesive,
The invention according to claim 7 provides:
In the near-infrared absorption filter for a plasma display panel according to the invention of claim 6,
The binder component is selected from an ultraviolet curable resin, a thermoplastic resin, a thermosetting resin, a room temperature curable resin, a metal alkoxide, and a hydrolysis polymer of a metal alkoxide,
The invention according to claim 8 provides:
In the near-infrared absorbing filter for a plasma display panel according to any one of claims 1 to 5,
The near-infrared absorbing material fine particles according to claim 1 or 3 or the near-infrared absorbing material fine particles and the organic compound according to claim 5 are dispersed in a binder resin and kneaded, and then formed into a board shape or a film shape. The molded article obtained above is characterized in that the near-infrared absorbing material fine particle dispersion is constituted,
The invention according to claim 9 is
In plasma display panels,
The near-infrared absorption filter for plasma display panels in any one of Claims 1-8 is provided.

Next, the invention according to claim 10 is
In the method for producing a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) as a raw material, and a general formula ZnxMyWOz (where Zn is zinc, M is Cs, Rb, K, Na, One or more elements selected from Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) is added to the raw material so that the composition is expressed by the following formula, and this mixture is added in a reducing gas atmosphere, an inert gas atmosphere, or a reducing gas and an inert gas. The near-infrared shielding material according to claim 1, which is heat-treated in a mixed atmosphere of active gas. To produce particles, characterized by obtaining the near-infrared-absorbing material microparticle dispersion with the near-infrared-absorbing material particles,
The invention according to claim 11 is:
In the method for producing a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) as a raw material, and the general formula LixMyWOz (where Li is lithium, M is Cs, Rb, K, Na, One or more elements selected from Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) A compound having lithium element is added to the raw material so as to have a composition represented by ≦ z ≦ 3.0), and the mixture is fired in the atmosphere or in an inert gas atmosphere, and then in a reducing gas atmosphere. Or, heat treatment in a mixed atmosphere of reducing gas and inert gas To produce a near-infrared shielding material fine particles according to 3, characterized in that to obtain the near-infrared-absorbing material microparticle dispersion with the near-infrared-absorbing material particles.

The invention according to claim 12
In the manufacturing method of the near-infrared absorption filter for plasma display panels which concerns on invention of Claim 10 or 11,
A near-infrared absorbing material fine particle produced by the method according to claim 10 or 11, wherein a diimonium compound, an aminium compound, a phthalocyanine compound, an organometallic complex, a cyanine compound, an azo compound, a polymethine compound, a quinone compound The above-mentioned near-infrared absorbing material fine particle dispersion is obtained by adding one or more organic compounds selected from diphenylmethane compounds and triphenylmethane compounds,
The invention according to claim 13 is:
In the manufacturing method of the near-infrared absorption filter for plasma display panels which concerns on invention in any one of Claims 10-12,
A near-infrared absorbing material fine particle produced by the method according to claim 10 or 11 or a coating liquid in which the near-infrared absorbing material fine particle and the organic compound according to claim 12 are dispersed in a liquid medium is used as a plasma display panel. It is characterized by being applied to the surface of a base material constituting a near infrared absorption filter for use to form a near infrared absorption material fine particle dispersion,
The invention according to claim 14 is
In the manufacturing method of the near-infrared absorption filter for plasma display panels which concerns on invention in any one of Claims 10-12,
The near-infrared absorbing material fine particles produced by the method according to claim 10 or 11, or the near-infrared absorbing material fine particles and the organic compound according to claim 12 are dispersed in a binder resin and kneaded, and then formed into a board shape or The film is formed into a film shape to form a near-infrared absorbing material fine particle dispersion.

According to the near-infrared absorbing filter for plasma display panel according to claim 1, which has a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed.
The near-infrared absorbing material fine particles have a general formula ZnxMyWOz (where Zn is zinc, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten) , O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0), which is a hexagonal crystal structure in which zinc is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg). 1 or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Greater than / a and the value is 1.027300 to 1.027700 And butterfly,
Moreover, according to the near-infrared absorption filter for plasma display panels which has the near-infrared absorption material fine particle dispersion by which the near-infrared absorption material fine particle was disperse | distributed,
The near-infrared absorbing material fine particles have a general formula LixMyWOz (where Li is lithium, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, and W is tungsten. , O is oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) and a hexagonal crystal structure in which lithium is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg). 1 or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Larger than / a, and the value is 1.027300 to 1.029000 It is characterized in Rukoto.

The fine particles of the composite tungsten oxide B having a hexagonal crystal structure in which zinc represented by the general formula ZnxMyWOz according to the first aspect is dissolved, and the lithium represented by the general formula LixMyWOz according to the third aspect are obtained. The fine particles of the composite tungsten oxide B having a solid solution hexagonal crystal structure have excellent wet heat resistance while maintaining high visible light transmittance and near infrared absorption, so The near-infrared absorption filter for plasma display panel applied as near-infrared absorbing material fine particles also has the characteristics of exhibiting excellent wet heat resistance while maintaining high visible light transmittance and near-infrared absorption,
In addition, the plasma display panel according to claim 9 provided with these near-infrared absorption filters for plasma display panels also has a characteristic of exhibiting excellent wet heat resistance while maintaining high visible light transmittance and near-infrared absorption. ing.

Next, according to the method for manufacturing a near-infrared absorption filter for a plasma display panel according to claim 10,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) as a raw material, and a general formula ZnxMyWOz (where Zn is zinc, M is Cs, Rb, K, Na, One or more elements selected from Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) is added to the raw material so that the composition is expressed by the following formula, and this mixture is added in a reducing gas atmosphere, an inert gas atmosphere, or a reducing gas and an inert gas. The near-infrared shielding material according to claim 1, which is heat-treated in a mixed atmosphere of active gas. To produce particles, characterized by obtaining the near-infrared-absorbing material microparticle dispersion with the near-infrared-absorbing material particles,
Moreover, according to the manufacturing method of the near-infrared absorption filter for plasma display panels which concerns on Claim 11,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) as a raw material, and the general formula LixMyWOz (where Li is lithium, M is Cs, Rb, K, Na, One or more elements selected from Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) A compound having lithium element is added to the raw material so as to have a composition represented by ≦ z ≦ 3.0), and the mixture is fired in the atmosphere or in an inert gas atmosphere, and then in a reducing gas atmosphere. Or, heat treatment in a mixed atmosphere of reducing gas and inert gas 3 is produced, and the near-infrared absorbing material fine particle dispersion is obtained by using the near-infrared absorbing material fine particles. Therefore, high visible light transmittance and near-infrared absorptivity are obtained. It is possible to produce a near-infrared absorption filter for a plasma display panel that exhibits excellent moisture and heat resistance while being maintained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The schematic diagram of the crystal structure of the composite tungsten oxide which has a hexagonal crystal. The schematic diagram of the hexagonal close-packed lattice for demonstrating ratio c / a of a lattice constant.

  Hereinafter, embodiments of the present invention will be described in detail.

A near-infrared absorbing filter for a plasma display panel according to the first invention having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
The near-infrared absorbing material fine particles have a general formula ZnxMyWOz (where Zn is zinc, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, and W is tungsten. , O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0), which is a hexagonal crystal structure in which zinc is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg). 1 or more elements, W is tungsten, O is oxygen, and the lattice constant ratio c of the composite tungsten oxide A expressed by 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Larger than / a, and the numerical value is 1.027300 to 1.027700. And butterfly,
Further, the near-infrared absorbing filter for plasma display panel according to the second invention having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
The near-infrared absorbing material fine particles have a general formula LixMyWOz (where Li is lithium, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, and W is tungsten. , O is oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) and a hexagonal crystal structure in which lithium is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg). 1 or more elements, W is tungsten, O is oxygen, and the lattice constant ratio c of the composite tungsten oxide A expressed by 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Larger than / a, and the value is 1.027300 to 1.029000 And wherein the Rukoto.

(1) Near-infrared absorbing material fine particles (ZnxMyWOz and LixMyWOz)
The first fine particles of the present invention applied to the near-infrared absorbing material fine particles are composed of composite tungsten oxide B fine particles having a hexagonal crystal structure in which zinc represented by the general formula ZnxMyWOz is solid-dissolved, and its lattice constant. The ratio c / a is larger than the lattice constant ratio c / a of the composite tungsten oxide A represented by the general formula MyWOz, and the numerical value is 1.027300 to 1.027700, The second fine particles of the present invention applied to the near-infrared absorbing material fine particles are composed of composite tungsten oxide B fine particles having a hexagonal crystal structure in which lithium represented by the general formula LixMyWOz is dissolved, and its lattice The ratio c / a of the constant is larger than the ratio c / a of the lattice constant of the composite tungsten oxide A represented by the general formula MyWOz, and the value is 1.02. Characterized in that it is a 300 to 1.029000.

  First, in the composite tungsten oxide represented by the general formula ZnxMyWOz, the general formula LixMyWOz, and the general formula MyWOz, the composition ratio z of oxygen (O) when the composition of tungsten (W) is 1, It is 2.2 or more and 3.0 or less as shown in the inside. When the composition ratio z is in this range, chemical stability as a material can be obtained, so that it can be applied as effective fine particles having near infrared absorption ability.

In addition, the composition ratio y of the element (M) when the composition of tungsten (W) is 1 is 0.1 or more and 0.5 from the viewpoint of optical characteristics as shown in parentheses of each general formula. The following is required. When the value of y is less than 0.1, the composite tungsten oxide represented by the general formula ZnxMyWOz, the general formula LixMyWOz, and the general formula MyWOz becomes unstable as a compound, and foreign phases such as WO ₃ and WO ₂ are precipitated. . Further, the larger the value of y, the better the near-infrared absorption ability, but the maximum value at which the composite tungsten oxide stably exists as a compound is 0.5 or less, and preferably around 0.33.

In addition, when the composite tungsten oxide fine particles represented by the general formula ZnxMyWOz, the general formula LixMyWOz, and the general formula MyWOz have a hexagonal crystal structure, the transmittance of the fine particles in the visible light region is improved and in the near infrared region. Improves absorption. This will be described with reference to FIG. 2, which is a schematic plan view of the hexagonal crystal structure. In FIG. 2, _six octahedrons formed by WO ₆ unit indicated by reference numeral 1 are assembled to form a hexagonal void, and the element (M) indicated by reference numeral 2 is arranged in the void. Thus, one unit is formed, and a large number of these one units are assembled to form a hexagonal crystal structure. When the cation of the element (M) is added to the hexagonal void, the absorption in the near infrared region is improved. Here, generally, when an element (M) having a large ionic radius is added, the hexagonal crystal is formed, which is preferable.

  When the composite tungsten oxide particles having a hexagonal crystal structure have a uniform crystal structure, the addition amount y of the element (M) is not less than 0.1 and not more than 0.5 as described above, and preferably 0.8. It is around 33. When the composition ratio z = 3 of oxygen (O), the value of y is 0.33, so that the element (M) is considered to be disposed in all hexagonal voids.

  In addition, the composite tungsten oxide B fine particles in which zinc represented by the general formula ZnxMyWOz is dissolved, and the composite tungsten oxide B fine particles in which lithium represented by the general formula LixMyWOz is solid-stated are the hexagonal crystals described above. Even when taking the structure of tetragonal or cubic tungsten bronze, it is effective as fine particles having near infrared absorption ability. The absorption position in the near infrared region tends to change depending on the crystal structure of the composite tungsten oxide B fine particles in which zinc or lithium is dissolved, and the absorption position in the near infrared region is more tetragonal than cubic. Tends to move to the longer wavelength side, and when it is hexagonal, it tends to move to the longer wavelength side than when it is tetragonal. Further, accompanying the change in the absorption position, the absorption in the visible light region is the smallest in the hexagonal crystal, the next is the tetragonal crystal, and the cubic is the largest among them. Therefore, as described above, it is necessary to use hexagonal tungsten bronze for the purpose of transmitting light in the visible light region and shielding light in the near infrared region. However, the tendency of the optical characteristics described here is merely a rough tendency, and varies depending on the kind of additive element, the amount of addition, and the amount of oxygen, and is not limited to this. Accordingly, a composite tungsten oxide B fine particle in which zinc represented by the general formula ZnxMyWOz produced by reacting a compound tungsten oxide A fine particle represented by the general formula MyWOz and a compound having a zinc element such as zinc carbonate is produced. Alternatively, the composite tungsten oxide A fine particles represented by the general formula LixMyWOz produced by reacting the compound tungsten oxide A fine particles represented by the general formula MyWOz with a compound having a lithium element such as lithium carbonate may be used. Even if a tetragonal or cubic tungsten bronze structure other than the hexagonal crystal described above is included, it can be used as the first and second fine particles of the present invention having near infrared absorption ability.

Next, in the composite tungsten oxide B represented by the general formula ZnxMyWOz, the composition ratio x of zinc (Zn) when the composition of tungsten (W) is 1 is shown in parentheses in the general formula. 0.001 ≦ x ≦ 2.0. Further, in the composite tungsten oxide B represented by the general formula LixMyWOz, the composition ratio x of lithium (Li) when the composition of tungsten (W) is 1, as shown in parentheses of the general formula 0.0001 ≦ x <0.1. In the composite tungsten oxide having a hexagonal crystal structure, when the composition ratio of oxygen (O) is z = 3, other than hexagonal voids formed by assembling six octahedrons formed of the above WO ₆ units In addition, three octahedrons that are also formed in units of WO ₆ are assembled to form a triangular void (tunnel). That is, although a site different from the M element exists, it is considered that zinc and lithium are arranged in a triangular void.

  And the ratio c / a of the lattice constant in the composite tungsten oxide B represented by the general formula ZnxMyWOz (see the hexagonal close-packed lattice symbols a and c shown in the schematic diagram of FIG. 3) is a compound containing a zinc element. It is confirmed that the lattice constant ratio c / a of the composite tungsten oxide A represented by the general formula MyWOz before the reaction is larger than the lattice constant ratio c / a of the composite tungsten oxide B represented by ZnxMyWOz. Therefore, it is considered that zinc (Zn) is in solid solution. More specifically, the ratio c / a of the lattice constant in the composite tungsten oxide B represented by the general formula ZnxMyWOz is the ratio c of the lattice constant of the composite tungsten oxide A represented by the general formula MyWOz as the starting material. More than 0.000050 compared to / a. On the other hand, the upper limit of the difference between the lattice constant ratio c / a of the composite tungsten oxide B and the lattice constant ratio c / a of the starting composite tungsten oxide A is 0.000400 or less. The reason why the upper limit is 0.000400 or less is that the lattice constant ratio c / a of the composite tungsten oxide B is larger than the lattice constant ratio c / a of the starting composite tungsten oxide A by more than 0.000400. This is because the lattice constant ratio c / a becomes excessive, and the element (M) described later tends to be desorbed, so that the improvement effect on the wet heat resistance is reduced. The ratio c / a of the lattice constant of the composite tungsten oxide B represented by the general formula ZnxMyWOz needs to be 1.027300 to 1.027700.

  In addition, the lattice constant ratio c / a in the composite tungsten oxide B expressed by the general formula LixMyWOz is equal to the lattice constant of the composite tungsten oxide A expressed by the general formula MyWOz before reacting with the compound having a lithium element. Since the ratio c / a of the lattice constant in the composite tungsten oxide B represented by LixMyWOz is confirmed to be larger than the ratio c / a, it is considered that lithium (Li) is also in solid solution. It is done. More specifically, the ratio c / a of the lattice constant in the composite tungsten oxide B expressed by the general formula LixMyWOz is the ratio c of the lattice constant of the composite tungsten oxide A expressed by the general formula MyWOz as the starting material. More than 0.000050 compared to / a. On the other hand, the upper limit of the difference between the lattice constant ratio c / a of the composite tungsten oxide B and the lattice constant ratio c / a of the starting composite tungsten oxide A is 0.001700 or less. The reason why the upper limit is 0.001700 or less is that the lattice constant ratio c / a of the composite tungsten oxide B is larger than the lattice constant ratio c / a of the starting composite tungsten oxide A by more than 0.001700. This is because the lattice constant ratio c / a becomes excessive, and the element (M) described later tends to be desorbed, so that the improvement effect on the wet heat resistance is reduced. And the ratio c / a of the lattice constant of the composite tungsten oxide B expressed by the general formula LixMyWOz needs to be 1.027300 to 1.029000.

  Further, the composite tungsten oxide represented by the general formula MyWOz before the reaction with the compound having the zinc element or the compound having the lithium element is also performed on the c-axis of the lattice constant in the composite tungsten oxide B represented by the general formula ZnxMyWOz or LixMyWOz. From the fact that it is confirmed that the lattice constant of the product A extends from the c-axis, it is considered that zinc (Zn) or lithium (Li) is dissolved. Here, the zinc (Zn) and lithium (Li) are in solid solution means that part or all of the added zinc or the added lithium supplied from the zinc element or the compound containing lithium element is in solid solution. State.

By the way, with respect to the composite tungsten oxide B in which zinc represented by the general formula ZnxMyWOz is dissolved, and the composite tungsten oxide B in which lithium represented by the general formula LixMyWOz is dissolved, the composite tungsten represented by the general formula MyWOz. The reason why the wet heat resistance is improved as compared with the oxide A is currently unknown, but the present inventors speculate as follows. First, it has been confirmed by the present inventors that the presence of moisture is deeply related to the deterioration phenomenon of the near-infrared absorptivity of the composite tungsten oxide A represented by the general formula MyWOz under wet heat conditions. The composite tungsten oxide A represented by the general formula MyWOz is an acidic oxide like WO ₃ and is unstable in moisture. When WO ₃ is immersed in water, the W component is eluted and the pH is lowered. When the composite tungsten oxide A represented by the general formula MyWOz is immersed in water, the W component is similarly eluted and the pH is lowered. At this time, when the element (M) is a basic element such as Cs, Rb, K, Na, Ba, Ca, Sr, etc., elution of the element (M) is promoted in the form of neutralizing the acidic aqueous solution. It is thought that near-infrared absorption ability falls.

  On the other hand, since the composite tungsten oxide B represented by the general formula ZnxMyWOz contains zinc (Zn) which is an amphoteric element in the composite tungsten oxide B, in order to neutralize the acidity caused by the W (tungsten) component. It is considered that zinc (Zn) is consumed and the elution of the element (M) is suppressed. From such an idea, when the zinc (Zn) composition ratio x of the composite tungsten oxide B represented by the general formula ZnxMyWOz is less than 0.001, the amount of Zn for suppressing elution of the element (M) is insufficient. Sufficient durability (moisture heat resistance) of the composite tungsten oxide B cannot be obtained. On the other hand, when the zinc (Zn) composition ratio x exceeds 2.0, the durability (wet heat resistance) of the composite tungsten oxide B is maintained, but the haze increases. The reason why the haze is increased is presumed to be due to the problem of matching with the dispersing agent used as zinc (Zn) increases. In addition, when the ratio c / a of the lattice constants exceeds 1.027700, the heat and humidity resistance decreases. However, although the details of this reason are not clear, it is presumed that the element (M) is easily desorbed. is doing.

  Similarly, it is considered that the composite tungsten oxide B represented by the general formula LixMyWOz also suppresses elution and desorption of the element (M) due to the solid solution of lithium (Li). When the lithium (Li) composition ratio x of the composite tungsten oxide B represented by the general formula LixMyWOz is less than 0.0001, the amount of Li for suppressing the elution and desorption of the element (M) is insufficient. A sufficient effect of the composite tungsten oxide B regarding heat resistance cannot be obtained. On the other hand, when the lithium (Li) composition ratio x is 0.1 or more, the heat resistance of the composite tungsten oxide B is deteriorated. Although the details of this reason are not clear, as in the case of zinc, it is assumed that desorption of the element (M) is facilitated when the ratio c / a of the lattice constants becomes excessive as Li increases. .

  In addition, the surface of the first and second fine particles of the present invention having near infrared absorption ability composed of the composite tungsten oxide B is coated with an oxide containing one or more elements of Si, Ti, Zr, and Al. It is preferable from the viewpoint of improving the weather resistance of the fine particles.

(2) Production of fine particles having near-infrared absorption ability composed of composite tungsten oxide B (a) First, general formula ZnxMyWOz (where Zn is zinc, M is Cs, Rb, K, Na, Ba, Ca, One or more elements selected from Sr and Mg, W is tungsten, O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3 0.0) In order to produce a composite tungsten oxide B fine particle having a hexagonal crystal structure in which zinc represented by a solid solution is represented by the general formula MyWOz (where M is Cs, Rb, K, Na, Ba) , Ca, Sr, Mg, one or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Composite tungsten oxide A was synthesized, and the resulting composite tungsten oxide A fine particles were Adding a compound having a lead element, the mixture can be prepared baking (heat treatment) to in a mixed atmosphere of a reducing gas atmosphere or an inert gas atmosphere or a reducing gas and an inert gas. When the mixture of the composite tungsten oxide A fine particles and the compound containing zinc element is fired (heat treatment) in a mixed atmosphere of a reducing gas and an inert gas, the concentration of the reducing gas in the inert gas is determined by firing. (Heat treatment) Although it will not specifically limit if it selects suitably according to temperature, Preferably it is 20 vol% or less, More preferably, it is 10 vol% or less, More preferably, it is 7-0.01 vol%. This is because when the concentration of the reducing gas in the inert gas is 20 vol% or less, rapid reduction of the composite tungsten oxide A fine particles can be avoided.

In addition, zinc oxide, zinc carbonate, or basic zinc carbonate can be applied as the compound having the zinc element. Among these, zinc carbonate (ZnCO ₃ ) or basic zinc carbonate [2ZnCO application of ₃ · 3Zn _{(OH) 2]} is desirable. It is desirable to apply these zinc carbonate and basic zinc carbonate by firing (heat treatment) in the reducing gas atmosphere, the inert gas atmosphere, or the mixed atmosphere of the reducing gas and the inert gas described above. This is because it is easy to produce fine particles of composite tungsten oxide B in which zinc is dissolved in the composite tungsten oxide A. Industrially, the composition of basic zinc carbonate composed of zinc carbonate and zinc hydroxide is indefinite, and the composition of the above [2ZnCO ₃ .3Zn (OH) ₂ ] represents a representative composition of basic zinc carbonate. Therefore, the composition of the basic zinc carbonate is not limited to [2ZnCO ₃ .3Zn (OH) ₂ ].

Next, the calcination (heat treatment) temperature may be appropriately selected according to the atmosphere. However, when the atmosphere is in an inert gas alone, it is more than 200 ° C. and less than 600 ° C. from the viewpoint of shortening the manufacturing time and single phase. , Preferably more than 300 ° C and less than 500 ° C, more preferably more than 350 ° C and less than 450 ° C. If the calcination (heat treatment) temperature is too low, it takes time to diffuse zinc atoms, which is not productive. Conversely, if the firing (heat treatment) temperature is too high, a heterogeneous phase is generated. On the other hand, when the atmosphere is a mixed atmosphere of an inert gas and a reducing gas, a temperature at which WO ₂ is not generated may be appropriately selected according to the reducing gas concentration. The firing (heat treatment) time at this time may be appropriately selected according to the temperature. However, it should be noted that when the treatment time is extended for a long time, the lattice constant ratio c / a of the composite tungsten oxide B represented by the general formula ZnxMyWOz may exceed the upper limit of 1.027700. . For example, if processing temperature exceeds 350 degreeC and less than 450 degreeC, processing time is 10 hours or less.

(B) Also, the general formula LixMyWOz (where Li is lithium, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is Oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) composite tungsten having a hexagonal crystal structure in which lithium is dissolved. In order to produce oxide B fine particles, first, general formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, and W is tungsten. , O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0), and composite tungsten oxide A represented by lithium element is synthesized into the obtained composite tungsten oxide A fine particles. The compound having After firing in a sexual gas atmosphere, it is possible to produce sintered (heat treatment) to in a mixed atmosphere of a reducing gas atmosphere or a reducing gas and an inert gas.

  When the mixture of the composite tungsten oxide A fine particles and the compound containing lithium element is baked in the atmosphere or an inert gas atmosphere and then baked (heat treatment) in a mixed atmosphere of a reducing gas and an inert gas, Although it will not specifically limit if the density | concentration of the reducing gas in active gas is suitably selected according to baking (heat processing) temperature, Preferably it is 20 vol% or less, More preferably, it is 10 vol% or less, More preferably, it is 7-0.01 vol. %. This is because when the concentration of the reducing gas in the inert gas is 20 vol% or less, rapid reduction of the composite tungsten oxide A fine particles can be avoided.

  The firing temperature may be appropriately selected according to the atmosphere, but when firing a mixture of the composite tungsten oxide A fine particles and the compound containing lithium element in the air, the temperature is higher than 650 ° C. and 1000 ° C. or lower. The firing (heat treatment) temperature in the reducing gas atmosphere or in the mixed atmosphere of reducing gas and inert gas is 400 ° C. or higher and 1000 ° C. or lower, preferably 500 ° C. or higher and 900 ° C. or lower. The firing (heat treatment) time may be appropriately selected according to the amount of treatment, but 5 minutes or more and 10 hours or less is sufficient. In addition, lithium carbonate is desirable for the compound having a lithium element.

  Further, when a mixture of the composite tungsten oxide A fine particles and the compound containing lithium element is baked in an atmosphere of an inert gas alone, it is more than 200 ° C. and less than 600 ° C. from the viewpoint of shortening the manufacturing time and single phase. The temperature is preferably more than 300 ° C. and less than 500 ° C., more preferably more than 350 ° C. and less than 450 ° C.

If the calcination (heat treatment) temperature is too low, it takes time to diffuse lithium atoms, which is not productive. Conversely, if the firing (heat treatment) temperature is too high, a heterogeneous phase is generated. On the other hand, when the mixture of the composite tungsten oxide A fine particles and the compound containing lithium element is fired in the air or in an inert gas atmosphere, and then fired (heat treatment) in a mixed atmosphere of a reducing gas and an inert gas. The temperature at which WO ₂ is not generated may be appropriately selected according to the reducing gas concentration. The firing (heat treatment) time at this time may be appropriately selected according to the selected temperature.

(C) Next, the above general formula ZnxMyWOz (wherein Zn is zinc, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O has a hexagonal crystal structure in which zinc represented by oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) is dissolved. Raw material for obtaining composite tungsten oxide B, and the above general formula LixMyWOz (where Li is lithium, M is one or more selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg) Element, W is tungsten, O is oxygen, and lithium represented by 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) is dissolved. A raw material for obtaining a composite tungsten oxide B having a hexagonal crystal structure, ie, one Formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0. 5, 2.2 ≦ z ≦ 3.0) will be described.

Tungsten acid (H ₂ WO ₄ ), ammonium tungstate, tungsten hexachloride, tungsten hydrate obtained by adding water to tungsten hexachloride dissolved in alcohol and hydrolyzing it, and then evaporating the solvent. As a compound having at least one selected tungsten compound and M element (Cs, Rb, K, Na, Ba, Ca, Sr, Mg), tungstate, chloride, nitrate, sulfate, oxalate , Oxides, carbonates, hydroxides, and other compounds having M element are dry-mixed, and the resulting mixed powder is mixed with an inert gas alone or in a mixed gas atmosphere of an inert gas and a reducing gas. It can be manufactured by one-step firing in steps, or the mixed powder can be fired in a mixed gas atmosphere of inert gas and reducing gas in the first step. An example is a method of producing by two-stage firing in an inert gas atmosphere in the second step. Note that tungsten oxide fine particles may be used instead of the tungsten compound.

Moreover, the following method is illustrated as a manufacturing method different from the said method. That is, as a tungsten compound, hydration of tungsten obtained by adding water to tungstic acid (H ₂ WO ₄ ), ammonium tungstate, tungsten hexachloride, tungsten hexachloride dissolved in alcohol, hydrolyzing it, and then evaporating the solvent. The mixture prepared by wet-mixing one or more tungsten compounds selected from the above and an aqueous solution containing the M element salt is dried to obtain a dried powder, and the resulting dried powder is converted into an inert gas. It is manufactured by firing in one step in a single step or in a mixed gas atmosphere of an inert gas and a reducing gas, or the dried powder is mixed in an inert gas and reducing gas atmosphere in the first step. And a method of producing by performing two-stage firing in which the second step is performed in an inert gas atmosphere. Note that tungsten oxide fine particles may be used instead of the tungsten compound. The salt of the M element is not particularly limited, and examples thereof include nitrates, sulfates, chlorides and carbonates. Moreover, the drying temperature and time at the time of drying the said liquid mixture prepared by wet mixing are not specifically limited.

  When the mixed powder or dry powder is fired in a mixed gas atmosphere of an inert gas and a reducing gas, the concentration of the reducing gas in the inert gas can be selected as appropriate depending on the firing temperature. Although not limited, Preferably it is 20 vol% or less, More preferably, it is 10 vol% or less, More preferably, it is 7-0.01 vol%. This is because when the concentration of the reducing gas in the inert gas is 20 vol% or less, rapid reduction of the mixed powder or dry powder can be avoided.

The firing temperature may be appropriately selected depending on the atmosphere, but when the mixed powder or dry powder is fired in an atmosphere of an inert gas alone, the composite tungsten oxide A fine particles represented by the general formula MyWOz are used. From the viewpoint of the crystallinity and coloring power, it exceeds 500 ° C. and is 1200 ° C. or less, preferably 1100 ° C. or less, more preferably 1000 ° C. or less. On the other hand, when the mixed powder or the dried powder is fired in a mixed gas atmosphere of an inert gas and a reducing gas, a temperature at which WO ₂ is not generated may be appropriately selected according to the reducing gas concentration. Furthermore, when producing composite tungsten oxide A fine particles by two-stage firing, firing is performed at 100 ° C. or more and 650 ° C. or less in a mixed gas atmosphere of an inert gas and a reducing gas at the first step. The conditions for firing at over 500 ° C. and below 1200 ° C. in an inert gas atmosphere are exemplified as preferred conditions from the viewpoint of near-infrared shielding properties. The firing treatment time at this time may be appropriately selected according to the firing temperature, but 5 minutes or more and 10 hours or less is sufficient.

Here, tungstic acid (H ₂ WO ₄ ), ammonium tungstate, tungsten hexachloride, tungsten hydrate obtained by adding water to tungsten hexachloride dissolved in alcohol and hydrolyzing it, and then evaporating the solvent, and A compound having M element such as tungstate, chloride, nitrate, sulfate, oxalate, oxide, carbonate, hydroxide, etc., for one or more tungsten compounds selected from tungsten oxide fine particles Is added using the dry mixing method described above, the compound having the element M is preferably an oxide or hydroxide.

  The dry mixing may be performed with a commercially available grinder, kneader, ball mill, sand mill, paint shaker, or the like.

(3) Near-infrared absorbing filter for plasma display panel (PDP) Near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles composed of fine particles of composite tungsten oxide B represented by the general formula ZnxMyWOz or LiMyWOz are dispersed In the near-infrared absorbing filter for PDP according to the present invention having the above, the near-infrared absorbing material exhibits efficient absorption of near-infrared and excellent wet heat resistance while maintaining transparency.

  And since the said near-infrared absorptive material microparticles | fine-particles absorb especially the light of 900-2200 nm vicinity largely, the transmitted color tone has many which become a green system from a blue system.

  When one or more kinds of fine particles selected from the fine particles of the composite tungsten oxide B are applied as a near-infrared absorbing material, the visible light region has a high transmittance in the wavelength range of 380 nm to 780 nm, and the near infrared region has a transmission wavelength of 780 nm to 1500 nm. The rate is lowered. The decrease in transmittance at wavelengths of 780 nm to 1500 nm is caused by absorption due to plasmon resonance due to conduction electrons of the composite tungsten oxide B fine particles. In the visible light region in the wavelength range of 380 nm to 780 nm, the amount of absorption is small compared to the absorption near 1000 nm, so the visibility is good, and the screen display can be confirmed sufficiently clearly even when installed on the front of the display. It becomes.

  Moreover, the near-infrared absorbing material fine particles according to the present invention composed of fine particles of composite tungsten oxide B represented by the general formula ZnxMyWOz or LiMyWOz in which zinc or lithium is solid-solved exhibit excellent wet heat resistance.

  When a near-infrared absorbing material fine particle dispersion is produced using the above-mentioned near-infrared absorbing material fine particles, a near-infrared absorbing material is formed on the surface of the base material constituting the near-infrared absorbing filter for PDP as an industrially inexpensive and simple method. A method of obtaining the above-mentioned near-infrared absorbing material fine particle dispersion by a coating film formed by applying a coating liquid containing fine particles and a binder component and / or an adhesive, and dispersing near-infrared absorbing material fine particles in a binder resin And then kneading into a board or film to obtain a near-infrared absorbing material fine particle dispersion, and the dispersion is laminated on the surface of the substrate constituting the near-infrared absorbing filter for PDP or between the substrates. The method of interposing is mentioned.

  When producing a near-infrared absorption filter for PDP by these methods, the dispersed particle diameter of the near-infrared absorbing material fine particles is 500 nm or less, preferably 200 nm or less, more preferably 100 nm or less. If the dispersed particle diameter of the fine particles is 500 nm or less, it is possible to prevent the light in the visible light region having a wavelength of 380 nm to 780 nm emitted from the display from being scattered by geometric scattering or Mie scattering to become frosted glass. It is preferable that a clear screen display is obtained. When the dispersed particle diameter is 200 nm or less, preferably 100 nm or less, the scattering is reduced and a Rayleigh scattering region is obtained. In the Rayleigh scattering region, the scattered light decreases in inverse proportion to the sixth power of the particle diameter, so that the scattering is reduced and a clear screen display is possible. Further, when the thickness is 100 nm or less, the scattered light is very small, which is more preferable. On the other hand, if the particle diameter is 1 nm or more, industrial production is possible.

(4) Manufacturing method of near-infrared absorbing filter for PDP (a) Method of obtaining near-infrared absorbing material fine particle dispersion by coating film Dispersed in coating solution containing near-infrared absorbing material fine particles, binder component and / or adhesive. As described above, the dispersed particle diameter of the near-infrared absorbing material fine particles is preferably 500 nm or less. A near-infrared absorption filter having high near-infrared absorption characteristics and excellent heat-and-moisture resistance characteristics while maintaining transparency by applying a coating liquid in which the dispersed fine particle diameter is sufficiently fine and uniformly dispersed up to 500 nm or less. Can be obtained.

  Here, the dispersed particle diameter of the near-infrared absorbing material fine particles in the coating solution will be briefly described. The dispersed particle diameter of the fine particles means the diameter of the aggregated particles formed by aggregation of the fine particles dispersed in the solvent, and can be measured with various commercially available particle size distribution analyzers. For example, a sample in a state where simple particles or aggregates exist from a fine particle dispersion (coating solution), and the sample is applied to ELS-8000 manufactured by Otsuka Electronics Co., Ltd. based on the principle of dynamic light scattering. It can be obtained by measuring.

  As described above, the dispersed particle size of the near-infrared absorbing material fine particles is preferably 500 nm or less. When the dispersed particle size is 500 nm or less, the obtained near-infrared absorption filter can be prevented from becoming a gray film or a molded body (plate, sheet, etc.) whose transmittance is monotonously reduced, and a high near-infrared ray This is because it exhibits absorption characteristics. Furthermore, if the fine particle dispersion (coating liquid) does not contain a large amount of aggregated coarse particles, these coarse particles may become a light scattering source, causing haze and reducing the visible light transmittance. This is preferable because it can be avoided.

  The method of dispersing the near-infrared absorbing material fine particles in the solvent is not particularly limited as long as it can uniformly disperse, for example, pulverization / dispersion using a bead mill, a ball mill, a sand mill, a paint shaker, an ultrasonic homogenizer, or the like. A processing method is mentioned. By the dispersion treatment using these equipments, the fine particles are also dispersed by the collision of the fine particles simultaneously with the dispersion of the fine particles in the solvent, so that the fine particles can be further dispersed (that is, pulverized / dispersed). ).

  The fine particle dispersion (coating liquid) contains a binder component and / or an adhesive, and examples of the binder component include inorganic binders and resin binders. Examples of the inorganic binder include metal alkoxides of silicon, zirconium, titanium, or aluminum, partially hydrolyzed polycondensation products thereof, or organosilazanes, and examples of the resin binder include heat such as an ultraviolet curable resin and an acrylic resin. Thermosetting resins such as plastic resins and epoxy resins, room temperature curing resins, and the like can be used.

  In the fine particle dispersion (coating liquid), the solvent for dispersing the fine particles is not particularly limited, and may be appropriately selected according to the application / kneading conditions, the application / kneading environment, and the type of the inorganic binder or resin binder. That's fine. Examples of the solvent include water, ethanol, propanol, butanol, isopropyl alcohol, isobutyl alcohol, diacetone alcohol and other alcohols, ethers such as methyl ether, ethyl ether and propyl ether, esters, acetone, methyl ethyl ketone, diethyl ketone, Various organic solvents such as ketones such as cyclohexanone and inbutylketone can be used. Further, if necessary, the pH may be adjusted by adding an acid or alkali, and various surfactants and coupling agents are used to further improve the dispersion stability of the fine particles in the fine particle dispersion (coating solution). Etc. may be added.

  Next, when a fine particle dispersion (coating liquid) is applied on the surface of a near infrared absorption filter base material for PDP made of plastic board, plastic film, glass, or the like to form a near infrared absorbing material fine particle dispersion, a coating method Is not particularly limited, and any method may be used as long as it can be applied thinly and uniformly, for example, spin coating, bar coating, spray coating, dip coating, screen printing, roll coating, flow coating, etc. .

  When the inorganic binder contains a metal alkoxide of silicon, zirconium, titanium, or aluminum and a hydrolysis polymer thereof, the substrate heating temperature after application of the fine particle dispersion (coating liquid) is 100 ° C. or higher. Thus, the polymerization reaction of the alkoxide or its hydrolysis polymer contained in the coating film can be almost completed. By almost completing the polymerization reaction, it is possible to avoid water and organic solvents remaining in the film and causing a reduction in the visible light transmittance of the film after heating. Therefore, the heating temperature is preferably 100 ° C. or higher. More preferably, it is not less than the boiling point of the solvent in the dispersion.

  In addition, when the resin binder is used, it may be cured according to the curing method of each resin binder. For example, if the resin binder is an ultraviolet curable resin, it may be appropriately irradiated with ultraviolet rays, and if it is a room temperature curable resin. What is necessary is just to leave as it is after application | coating.

  By such a method, a near-infrared absorbing filter for PDP in which a near-infrared absorbing material fine particle dispersion is formed on a near-infrared absorbing filter substrate for PDP can be obtained. In the filter, the near-infrared absorption efficiency can be adjusted by changing the film thickness of the near-infrared absorbing material fine particle dispersion. Furthermore, the binding property of the near-infrared absorbing material fine particle dispersion to the base material can be increased by blending the fine particle dispersion (coating liquid) with an appropriate binder composed of the above-described inorganic binder and resin binder. It is also a preferable configuration to improve and provide a protective function on the filter surface and a binding function to the main body.

  Moreover, the multilayer laminated near-infrared absorber fine particle dispersion imparted with the antireflection function may be formed on the surface of the front panel of the PDP. The multilayer laminated near-infrared absorber fine particle dispersion is an antireflection near-infrared absorber fine particle dispersion using light interference utilizing a refractive index difference. For example, a high refractive index layer and a low refractive index layer are alternately arranged. Have a laminated structure. Here, since the near-infrared absorbing material fine particles according to the present invention have a high refractive index of 2.3 or more, the near-infrared absorbing material fine particle dispersion in which the near-infrared absorbing material fine particles are dispersed by mixing with an appropriate binder or the like. By forming this, the near-infrared absorbing fine particle dispersion can be applied as a part of the antireflection film as a high refractive index layer.

  Here, various binders can be used as the binder, and may be appropriately selected depending on the type of base material, required characteristics of the filter, the configuration of the filter, and the like. Specifically, ultraviolet curable resin, thermosetting resin, thermoplastic resin, room temperature curable resin, metal alkoxide, sol-gel solution using hydrolyzed polymer of metal alkoxide and various pressure-sensitive adhesives constituting the inorganic binder and resin binder described above. Etc. can be illustrated. In particular, when an ultraviolet curable resin is used, the production efficiency in the manufacturing process is high, and since the ultraviolet curable resin also has a hard coat property, by using an ultraviolet curable hard coat resin as a binder, It becomes possible to obtain a near-infrared absorbing material filter that achieves both wear resistance imparting to a substrate and a near-infrared absorbing function in a single layer.

  The near-infrared absorbing materials such as organic compounds and metal complexes described above are decomposed by ultraviolet rays or heat, so that they are dispersed in an ultraviolet curable resin, used in combination with a binder that is cured at high temperature, and alcohol or water having low solubility is used as a solvent. However, in the present invention, since the powder of inorganic oxide fine particles having high stability is applied as described above, kneading into an ultraviolet curable resin is possible. The UV curing can cure the film with an irradiation time of several seconds or less, and the present invention is extremely useful because it is a method with very high production efficiency.

  Further, when glass is used as a filter substrate, a metal alkoxide such as silicate can be used as a binder. A mixture of near-infrared absorbing material fine particles composed of at least one kind of fine particles selected from the above-mentioned tungsten oxide fine particles and composite tungsten oxide fine particles and oxide fine particles of additive elements and metal alkoxide are uniformly coated on glass. And by baking, it becomes possible to obtain a near-infrared absorbing material filter with strong surface strength.

  The obtained near-infrared absorbing material filter is provided on the front surface of the PDP main body by an appropriate method such as a mechanical method or an adhesion method, thereby avoiding a situation in which surrounding electronic devices malfunction due to near-infrared rays generated from the PDP. can do.

  Further, by selecting a material having adhesiveness as a binder and providing a near-infrared absorbing function for the adhesive layer when a plastic film or board is bonded to the front glass of the PDP body, the front surface of the PDP body It is also possible to make a near-infrared absorbing material filter using glass as a base material and the adhesive layer as a near-infrared absorbing layer.

  In addition, by selecting the binder, the fine particle dispersion (coating solution) is directly applied onto the front glass of the PDP main body, the solvent is evaporated, and various optimum curing methods are used, thereby the PDP main body. It is also possible to make a near-infrared absorbing material filter in which a near-infrared absorbing material fine particle dispersion in which a near-infrared absorbing material is dispersed is provided on the base glass.

  It is also preferable to add a dye or a pigment to the near-infrared absorbing material fine particle dispersion for color tone adjustment. In particular, color tone adjustment that contributes to improving contrast is an effective method for improving the image quality of PDP. Near-infrared absorbing material fine particles composed of composite tungsten oxide B fine particles represented by the general formula ZnxMyWOz or LiMyWOz, diimonium compounds, aluminum compounds, phthalocyanine compounds, organometallic complexes, cyanine compounds, azo It is also preferable to use in combination with one or more organic compounds selected from compounds, polymethine compounds, quinone compounds, diphenylmethane compounds, and triphenylmethane compounds. By adopting this configuration, the effect of improving the weather resistance can be obtained as compared with the case where an organic compound or a metal complex is used alone.

(B) A method of obtaining a near-infrared absorbing material fine particle dispersion by a molded body formed into a board or a film. Near-infrared absorbing material fine particles composed of composite tungsten oxide B fine particles represented by the general formula ZnxMyWOz or LiMyWOz are dispersed. The solvent component is removed from the fine particle dispersion (coating liquid) or the fine particle dispersion (coating liquid) containing the near-infrared absorbing material fine particles and the binder component to obtain a near-infrared absorbing material powder.

  The near-infrared absorbing material fine particles (powder) can be kneaded as they are in a resin constituting the filter base material to produce a plastic board or a plastic film. Here, when the near-infrared absorbing material fine particles are kneaded into the resin, generally it is heated and mixed at a temperature near the melting point of the resin (around 200 to 300 ° C.), so an organic compound such as a dye is used as the near-infrared absorbing material. In such a case, the heat resistance of the organic compound is limited, and the kneading work is difficult. However, in the present invention, since fine particles of composite tungsten oxide B represented by the general formula ZnxMyWOz or LiMyWOz having high heat resistance are used, mixing at around 200 to 300 ° C., which is the melting point of ordinary resins, is also possible. .

  It is also possible to pelletize the resin mixed with the powder of the near-infrared absorbing material and form the resin pellet using the resin pellet. For example, a transparent resin (base resin) is selected and formed using a known T-die molding method, calendar molding method, compression molding method, casting method, etc. A resin film (near-infrared absorbing material fine particle dispersion) can be formed.

  The thickness of the near-infrared absorbing material fine particle dispersion in which the near-infrared absorbing material fine particles are dispersed depends on the purpose of use, but a film or board in the range of 10 μm to 3 mm is desirable. At this time, the compounding quantity of the said near-infrared absorption material microparticles | fine-particles with respect to base resin can be arbitrarily set according to the thickness of a base material, or the required optical characteristic.

  Specific examples of the base resin include polyolefin resin, polyester resin, polycarbonate resin, poly (meth) acrylate ester resin, polystyrene, polyvinyl chloride, from the viewpoint of optical properties and mechanical properties. Polyvinyl acetate, polyarylate resin, polyethersulfone resin and the like can be mentioned. Among these resins, amorphous polyolefin resins, polyester resins, polycarbonate resins, poly (meth) acrylate resins, polyarylate resins, and polyethersulfone resins are preferable. Then, cyclic polyolefin is more preferable, and polyethylene terephthalate is more preferable among polyester resins. As the base material other than the resin, glass is preferable from the viewpoint of optical properties and mechanical properties.

  Also, a polyvinyl butyral (PVB) resin is selected as the base resin, and a plastic sheet or plastic film in which fine particles of near-infrared absorbing material are dispersed in the base resin is sandwiched between transparent base materials such as glass. A vitrified near-infrared absorption filter is also a preferable configuration as a near-infrared absorption filter for PDP.

  Examples of the present invention will be specifically described below together with comparative examples. However, the present invention is not limited to the contents of the following examples. In each example, measurement is performed by a method according to JIS A 5759 (however, measurement is performed without attaching to glass).

  That is, the transmittance is measured using a spectrophotometer (Hitachi U-4000) at a wavelength of 200 nm to 2600 nm at intervals of 5 nm.

  The haze value of the film was measured according to JIS K 7105.

  The average dispersed particle diameter was an average value measured by a measuring apparatus using a dynamic light scattering method [ELS-800 manufactured by Otsuka Electronics Co., Ltd.].

[Example 1]
An aqueous solution in which 7.43 kg of cesium carbonate was dissolved in 6.70 kg of water was added to 34.57 kg of tungstic acid (H ₂ WO ₄ ). After mixing, water was removed while stirring at 100 ° C. to dry powder. Got.

Next, while supplying 5% H ₂ gas with N ₂ gas as a carrier (that is, in a mixed gas atmosphere of an inert gas and a reducing gas), the dry powder is heated and heated at a temperature of 800 ° C. After baking for 5.5 hours, Cs _0.33 WO ₃ fine particles (that is, composite tungsten oxide A fine particles) were obtained. As a result of identifying the crystal phase of the calcined powder obtained by the calcining treatment by X-ray diffraction, it was Cs _0.33 WO ₃ single phase, and the lattice constant ratio c / a was 1.027547.

Next, 10 g of the above-mentioned Cs _0.33 WO ₃ fine particles and 4.05 g of basic zinc carbonate are sufficiently mixed by a crusher, and heat-treated at 400 ° C. for 1 hour in an N ₂ gas atmosphere. _1.0 Cs _0.33 WO ₃ fine particles (ie, composite tungsten oxide B fine particles) were produced. As a result of identifying the crystal phase of the calcined powder by X-ray diffraction, a main peak attributed to Cs _0.33 WO ₃ and a weak peak attributed to ZnO were observed. In addition, since no peak of Cs ₂ compound such as Cs ₂ O or Cs metal is observed, substitution of Cs and Zn and liberation of Cs atoms do not occur. Further, the lattice constant c / a of Zn _1.0 Cs _0.33 WO ₃ fine particles was 1.027678, and the ratio c / a (1.027547) of the lattice constant of Cs _0.33 WO ₃ fine particles not containing zinc was 1.027678. It was larger than that, and it was confirmed that a part of the added zinc was dissolved.

Next, 10.37% by weight of the above Zn _1.0 Cs _0.33 WO ₃ fine particles (8% by weight in terms of Cs _0.33 WO ₃ ), 8% by weight of a polymeric dispersant (solid content 40%), Zn _1.0 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) were obtained by weighing 81.63 wt% of toluene and grinding and dispersing for 9 hours in a paint shaker containing 0.3 mmφZrO ₂ beads. A dispersed dispersion (liquid A) was obtained. In addition, the particle diameter of the Zn _1.0 Cs _0.33 WO ₃ fine particles in the dispersion (liquid A) was 10 to 50 nm as a result of TEM observation.

Next, 66.7% by weight of the above dispersion (liquid A) and 33.3% by weight of UV curable resin [UV3701 manufactured by Toa Gosei Co., Ltd.] were mixed well, and Zn _1.0 Cs _0.33 WO ₃ A coating solution containing fine particles (composite tungsten oxide B fine particles) was prepared, and a coating film was formed by applying the coating solution on a 50 μm thick PET (polyethylene terephthalate) film using a bar coater with a count of 24. And after drying at 70 ° C. for 1 minute to evaporate the solvent, the coating film is cured by irradiating the coating film with ultraviolet rays using a high-pressure mercury lamp, and a near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) is formed. Obtained.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 63.5% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. Further, the transmittance at a wavelength of 1000 nm was 2.1%, and it was confirmed that the filter was a good near infrared filter. Furthermore, the haze at this time was 1.5%, and it was confirmed that the transparency was high.

  Next, the following accelerated deterioration test was conducted in order to investigate the heat and heat resistance characteristics.

  That is, after forming a near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) by forming a film on a PET film so that the transmittance at 820 nm is 17% using the above coating solution, It was exposed to a ° C-95% RH atmosphere, and the change rate of the 820 nm transmittance after 5 days (hereinafter referred to as ΔT 820 nm transmittance) was examined.

  As a result, as shown in Table 1, the ΔT820 nm transmittance after 5 days was 3.0%, and an improvement in heat and moisture resistance was confirmed as compared with Comparative Example 1 described below.

[Example 2]
The same procedure as in Example 1 except that 2.03 g of basic zinc carbonate was added instead of the condition of Example 1 in which 4.05 g of basic zinc carbonate was added to 10 g of Cs _0.33 WO ₃ fine particles. Thus, Zn _0.5 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) according to Example 2 were manufactured, and the near-infrared absorbing film according to Example 2 (near Infrared absorbing material fine particle dispersion) was produced.

As a result of identifying the crystal phase of the calcined powder according to Example 2 by X-ray diffraction, a peak attributed to Cs _0.33 WO ₃ and a weak peak attributed to ZnO were observed. In addition, since no peak of Cs ₂ compound such as Cs ₂ O or Cs metal is observed, substitution of Cs and Zn and liberation of Cs atoms do not occur. Further, the lattice constant c / a of Zn _0.5 Cs _0.33 WO ₃ fine particles is 1.027646, and the ratio c / a of the lattice constant of Cs _0.33 WO ₃ fine particles not containing zinc (1.027547). ), And it was confirmed that a part of the added zinc was dissolved. _{Further, Zn 0.5 Cs 0.33 WO 3 Zn} 0.5 fine particles dispersion was prepared in the same manner as in Example 1 so as to be 8% by weight _{Cs 0.33} WO ₃ terms (A solution) in The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 65.3% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. Further, the transmittance at a wavelength of 1000 nm was 2.7%, and it was confirmed that the filter was a good near infrared filter. Furthermore, the haze at this time was 1.5%, and it was confirmed that the transparency was high.

  Further, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 2.7% as shown in Table 1, and it was confirmed that the moisture and heat resistance was improved as compared with Comparative Example 1 below.

[Example 3]
The same procedure as in Example 1 except that 3.24 g of basic zinc carbonate was added instead of the condition of Example 1 in which 4.05 g of basic zinc carbonate was added to 10 g of Cs _0.33 WO ₃ fine particles. Thus, Zn _0.8 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) according to Example 3 were manufactured, and the near-infrared absorbing film according to Example 3 (near Infrared absorbing material fine particle dispersion) was produced.

As a result of identifying the crystal phase of the calcined powder according to Example 3 by X-ray diffraction, a peak attributed to Cs _0.33 WO ₃ and a weak peak attributed to ZnO were observed. In addition, since no peak of Cs ₂ compound such as Cs ₂ O or Cs metal is observed, substitution of Cs and Zn and liberation of Cs atoms do not occur. The lattice constant c / a of Zn _0.8 Cs _0.33 WO ₃ fine particles is 1.027677, and the ratio c / a of the lattice constant of Cs _0.33 WO ₃ fine particles not containing zinc (1.027547). ), And it was confirmed that a part of the added zinc was dissolved. _{Further, Zn 0.8 Cs 0.33 WO 3 Zn} 0.8 of microparticles _{Cs 0.33} WO ₃ were prepared in the same manner as in Example 1 so as to be 8 wt% in terms of dispersion (A solution) The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  When the optical properties of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 63.4% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. Further, the transmittance at a wavelength of 1000 nm was 2.1%, and it was confirmed that the filter was a good near infrared filter. Furthermore, the haze at this time was 1.5%, and it was confirmed that the transparency was high.

  Further, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 3.4% as shown in Table 1, and it was confirmed that the moisture and heat resistance was improved as compared with Comparative Example 1 below.

[Example 4]
Instead of the condition of Example 1 in which 4.05 g of basic zinc carbonate was added to 10 g of Cs _0.33 WO ₃ fine particles, 6.08 × 10 ⁻² g of basic zinc carbonate was added, and N ₂ Zn _0.015 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) according to Example 4 were obtained in the same manner as in Example 1 except that the treatment was performed at 400 ° C. for 3 hours in a gas atmosphere. In the same manner as in Example 1, a near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) according to Example 4 was manufactured.

As a result of identifying the crystal phase of the calcined powder according to Example 4 by X-ray diffraction, a peak attributed to Cs _0.33 WO ₃ and a weak peak attributed to ZnO were observed. In addition, since no peak of Cs ₂ compound such as Cs ₂ O or Cs metal is observed, substitution of Cs and Zn and liberation of Cs atoms do not occur. The lattice constant c / a of Zn _0.015 Cs _0.33 WO ₃ fine particles is 1.027630, and the ratio c / a of the lattice constant of Cs _0.33 WO ₃ fine particles not containing zinc (1.027547) ), And it was confirmed that all of the added zinc was dissolved.

_{Further, Zn 0.015 Cs 0.33 WO 3 Zn} 0.015 fine particles dispersion was prepared in the same manner as in Example 1 so as to be 8% by weight _{Cs 0.33} WO ₃ terms (A solution) in The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 65.7% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. The transmittance at a wavelength of 1000 nm was 2.3%, and it was confirmed that the filter was a good near infrared filter. Furthermore, the haze at this time was 1.4%, and it was confirmed that the transparency was high.

  Further, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 6.5% as shown in Table 1, and it was confirmed that the moisture and heat resistance was improved as compared with Comparative Example 1 below.

[Example 5]
Instead the Cs _0.33 WO ₃ with respect to particulate 10g basic zinc carbonate in the conditions of Example 1 was added 4.05 _g, the _{Cs 0.33} WO ₃ fine particles 10g lithium carbonate to 2.68 × 10 ^-3 g Add, mix well in a crusher, bake in the atmosphere at 800 ° C. for 6 hours, and then feed 20% at 800 ° C. while supplying 1.6% H ₂ gas with N ₂ gas as a carrier. Li _0.002 Cs _0.33 WO ₃ fine particles (that is, composite tungsten oxide B fine particles) are produced by partial heat treatment, and the near-infrared absorbing film according to Example 5 ( A near-infrared absorbing material fine particle dispersion) was produced.

In addition, as a result of identification of the crystal phase by X-ray diffraction of the baked powder according to Example 5, only a peak attributed to Cs _0.33 WO ₃ was observed. The lattice constant ratio c / a is 1.027630, which is larger than the lattice constant ratio c / a of the Cs _0.33 WO ₃ fine particles not containing lithium, and all of the added lithium is It was confirmed that it was dissolved.

_{Also, Li 0.002 Cs 0.33 WO 3 Li} 0.002 fine particles dispersion was prepared in the same manner as in Example 1 so as to be 8% by weight _{Cs 0.33} WO ₃ terms (A solution) in The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 66.8% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. Moreover, the transmittance | permeability with a wavelength of 1000 nm was 3.0%, and it was confirmed that it is a favorable near-infrared filter. Furthermore, the haze at this time was 1.3%, and it was confirmed that the transparency was high.

  Further, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 5.1% as shown in Table 1, and it was confirmed that the moisture and heat resistance was improved as compared with Comparative Example 1 below.

[Example 6]
Cs _0.33 WO ₃ with respect to particulate 10g instead conditions of Example 5 with the addition of lithium carbonate _{^{2.68 × 10 -3 g, Cs 0.33}} WO 3 fine particles 10g to lithium carbonate 6.71 × 10 ^- Li _0.005 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) according to Example 6 were produced in the same manner as Example 5 except that ³ g was added. Similarly, a near-infrared absorbing film according to Example 6 (near-infrared absorbing material fine particle dispersion) was produced.

As a result of identification of the crystal phase of the calcined powder according to Example 6 by X-ray diffraction, only a peak attributed to Cs _0.33 WO ₃ was observed. The lattice constant ratio c / a is 1.027659, which is larger than the lattice constant ratio c / a of the Cs _0.33 WO ₃ fine particles not containing lithium. It was confirmed that it was dissolved.

_{Also, Li 0.005 Cs 0.33 WO 3 Li} 0.005 fine particles dispersion was prepared in the same manner as in Example 1 so as to be 8% by weight _{Cs 0.33} WO ₃ terms (A solution) in The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 65.1% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. The transmittance at a wavelength of 1000 nm was 2.3%, and it was confirmed that the filter was a good near infrared filter. Furthermore, the haze at this time was 1.2%, and it was confirmed that the transparency was high.

  Further, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 5.1% as shown in Table 1, and it was confirmed that the moisture and heat resistance was improved as compared with Comparative Example 1 below.

[Example 7]
Cs _0.33 WO ₃ with respect to particulate 10g instead conditions of Example 5 with the addition of lithium carbonate _{^{2.68 × 10 -3 g, Cs 0.33}} WO 3 fine particles 10g to lithium carbonate 1.34 × 10 ^- Li _0.010 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) according to Example 7 were produced in the same manner as in Example 5 except that ² g was added. Similarly, a near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) according to Example 7 was produced.

As a result of identifying the crystal phase of the calcined powder according to Example 7 by X-ray diffraction, only the peak attributed to Cs _0.33 WO ₃ was observed. The lattice constant ratio c / a is 1.027798, which is larger than the lattice constant ratio c / a of the Cs _0.33 WO ₃ fine particles not containing lithium. It was confirmed that it was dissolved.

_{Also, Li 0.010 Cs 0.33 WO 3 Li} 0.010 fine particles dispersion was prepared in the same manner as in Example 1 so as to be 8% by weight _{Cs 0.33} WO ₃ terms (A solution) in The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 67.0% as shown in Table 1, and the front light emission of the display was sufficiently transmitted. Confirmed to do. Moreover, the transmittance | permeability of wavelength 1000nm was 2.9%, and it was confirmed that it is a favorable near-infrared filter. Furthermore, the haze at this time was 1.3%, and it was confirmed that the transparency was high.

  Further, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 4.8% as shown in Table 1, and it was confirmed that the moisture and heat resistance was improved as compared with Comparative Example 1 below.

[Comparative Example 1]
A near-infrared absorbing film according to Comparative Example 1 (except that the Cs _0.33 WO ₃ fine particles (composite tungsten oxide A fine particles) produced in Example 1 were used as the near-infrared shielding material fine particles. A near-infrared absorbing material fine particle dispersion) was produced.

The Cs _0.33 WO ₃ fine particles according to Comparative Example 1 were Cs _0.33 WO ₃ single phase as in Example 1, and the lattice constant ratio c / a was 1.027547.

Further, the particle diameter of the Cs _0.33 WO ₃ fine particles in the dispersion (liquid A) prepared in the same manner as in Example 1 so that the amount of Cs _0.33 WO ₃ fine particles is 8% by weight is the result of TEM observation. 10 to 50 nm.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 69.5% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. Moreover, the transmittance | permeability of wavelength 1000nm was 4.3%, and it was confirmed that it is a favorable near-infrared filter. Furthermore, the haze at this time was 1.5%, and it was confirmed that the transparency was high.

  However, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 11.4% as shown in Table 1, and it was confirmed that the heat and moisture resistance was significantly inferior compared with Examples 1-7. .

[Comparative Example 2]
Instead of the conditions of Example 1 in which 4.05 g of basic zinc carbonate was added to 10 g of Cs _0.33 WO ₃ fine particles, 8.10 × 10 ⁻² g of basic zinc carbonate was added, and an N ₂ gas atmosphere According to Comparative Example 2 as in Example 1, except that the heat treatment was performed for 12 hours under the condition of 400 ° C. under N ₂ gas atmosphere instead of the condition of Example 1 where the heat treatment was performed for 1 hour under the condition of 400 ° C. Zn _0.02 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) are produced, and the near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) according to Comparative Example 2 in the same manner as Example 1 Manufactured.

As a result of identifying the crystal phase of the fired powder according to Comparative Example 2 by X-ray diffraction, a peak attributed to Cs _0.33 WO ₃ and a weak peak attributed to ZnO were observed. In addition, since no peak of Cs ₂ compound such as Cs ₂ O or Cs metal is observed, substitution of Cs and Zn and liberation of Cs atoms do not occur. The lattice constant c / a of the Zn _0.02 Cs _0.33 WO ₃ fine particles is 1.027706 (that is, outside the above-mentioned “1.027300 to 1.027700” range of the present invention), and does not contain zinc. It was larger than the lattice constant ratio c / a (1.027547) of Cs _0.33 WO ₃ fine particles, and it was confirmed that a part of the added zinc was dissolved.

_{Further, Zn 0.02 Cs 0.33 WO 3 Zn} 0.02 fine particles dispersion was prepared in the same manner as in Example 1 so as to be 8% by weight _{Cs 0.33} WO ₃ terms (A solution) in The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  Then, when the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 65.1% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. Moreover, the transmittance | permeability with a wavelength of 1000 nm was 3.0%, and it was confirmed that it is a favorable near-infrared filter. Furthermore, the haze at this time was 1.3%, and it was confirmed that the transparency was high.

  However, the ΔT820 nm transmittance after 5 days in the accelerated deterioration test was 11.0% as shown in Table 1, and it was confirmed that the heat and moisture resistance was significantly inferior compared with Examples 1-7. .

[Comparative Example 3]
Cs _0.33 WO ₃ with respect to particulate 10g instead conditions of Example 5 with the addition of lithium carbonate _{^{2.68 × 10 -3 g, Cs 0.33}} WO 3 fine particles 10g to lithium carbonate 1.34 × 10 ^- Li _0.10 Cs _0.33 WO ₃ fine particles (composite tungsten oxide B fine particles) according to Comparative Example 3 were produced in the same manner as in Example 5 except that ¹ g was added. Similarly, a near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) according to Comparative Example 3 was produced.

In addition, as a result of the identification of the crystal phase by X-ray diffraction of the fired powder according to Comparative Example 3, only the peak attributed to Cs _0.33 WO ₃ was observed. Further, the ratio c / a of the lattice constant is 1.029107 (that is, outside the above “1.027300 to 1.029000” range of the present invention), and the lattice constant of the Cs _0.33 WO ₃ fine particles not containing lithium is The ratio was larger than the ratio c / a (1.027547), and it was confirmed that all of the added lithium was dissolved.

_{Also, Li 0.10 Cs 0.33 WO 3 Li} 0.10 fine particles dispersion was prepared in the same manner as in Example 1 so as to be 8% by weight _{Cs 0.33} WO ₃ terms (A solution) in The particle diameter of the Cs _0.33 WO ₃ fine particles was 10 to 50 nm as a result of TEM observation.

  When the optical characteristics of the obtained near-infrared absorbing film (near-infrared absorbing material fine particle dispersion) were measured, the visible light transmittance was 67.1% as shown in Table 1, and the front emission of the display was sufficiently transmitted. Confirmed to do. Moreover, the transmittance | permeability of wavelength 1000nm was 5.0%, and it was confirmed that it is a favorable near-infrared filter. Furthermore, the haze at this time was 1.3%, and it was confirmed that the transparency was high.

  However, the ΔT820 nm transmittance after 5 days in the accelerated degradation test was 17.3% as shown in Table 1, and it was confirmed that the heat and humidity resistance was significantly inferior compared with Examples 1-7. .

  According to the near-infrared absorption filter for a plasma display panel according to the present invention, since it exhibits excellent resistance to wet heat while maintaining high visible light transmittance and near-infrared absorption, it is applied to a plasma display panel. Has industrial applicability.

1 WO ₆ units 2 Element (M)
11 Front glass substrate (front cover plate)
12 Display electrode 13 Dielectric glass layer 14 Protective layer made of magnesium oxide (MgO) 15 Back glass substrate (back plate)
16 Address electrode 17 Partition 18 Phosphor layer 19 Discharge space for enclosing discharge gas

Claims (14)

In a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
The near-infrared absorbing material fine particles have a general formula ZnxMyWOz (where Zn is zinc, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten) , O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0), which is a hexagonal crystal structure in which zinc is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg). 1 or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Greater than / a and the value is 1.027300 to 1.027700 Near-infrared absorption filter for plasma display panel and butterflies.   General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) and a mixture of the compound having a zinc element and a compound having a zinc element in a reducing gas atmosphere, an inert gas atmosphere, or a reducing gas. 2. The composite tungsten oxide B fine particles according to claim 1 represented by the general formula ZnxMyWOz are obtained by heat treatment in a mixed atmosphere of an inert gas and an inert gas. 3. Near-infrared absorption filter for plasma display panels. In a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
The near-infrared absorbing material fine particles have a general formula LixMyWOz (where Li is lithium, M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, and Mg, and W is tungsten. , O is oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) and a hexagonal crystal structure in which lithium is dissolved. The ratio of the lattice constant c / a is selected from the general formula MyWOz (where M is selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg). 1 or more elements, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) Larger than / a, and the value is 1.027300 to 1.029000 Near-infrared absorption filter for plasma display panel characterized by Rukoto.   General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) and a mixture of a compound having a lithium element and a compound having a lithium element is calcined in the atmosphere or in an inert gas atmosphere, and then reduced gas. The fine particles of the composite tungsten oxide B according to claim 3, which are heat-treated in an atmosphere or a mixed atmosphere of a reducing gas and an inert gas, are represented by the general formula LixMyWOz. The near-infrared absorption filter for plasma display panels of Claim 3.   The near-infrared absorbing material fine particle dispersion is a diimonium compound, an aminium compound, a phthalocyanine compound, an organometallic complex, a cyanine compound, an azo compound, a polymethine compound, a quinone compound, a diphenylmethane compound, or a triphenylmethane compound. The near-infrared absorption filter for a plasma display panel according to any one of claims 1 to 4, comprising at least one organic compound selected from the group consisting of:   The near-infrared absorbing material fine particles according to claim 1 or 3 or the near-infrared absorbing material fine particles, the organic compound according to claim 5, a binder component, and / or a surface of a substrate constituting a near-infrared absorbing filter for a plasma display panel. 6. The near-infrared absorbing material fine particle dispersion is constituted by a coating film formed by coating a coating solution containing an adhesive. 6. The plasma display panel according to claim 1, Near infrared absorption filter.   The plasma display panel according to claim 6, wherein the binder component is selected from an ultraviolet curable resin, a thermoplastic resin, a thermosetting resin, a room temperature curable resin, a metal alkoxide, and a hydrolysis polymer of a metal alkoxide. Near infrared absorption filter.   The near-infrared absorbing material fine particles according to claim 1 or 3 or the near-infrared absorbing material fine particles and the organic compound according to claim 5 are dispersed in a binder resin and kneaded, and then formed into a board shape or a film shape. The near-infrared absorbing filter for plasma display panels according to any one of claims 1 to 5, wherein the near-infrared-absorbing material fine particle dispersion is constituted by the molded body obtained in this manner.   A near-infrared absorption filter for a plasma display panel according to any one of claims 1 to 8, wherein the plasma display panel is provided. In the method for producing a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) as a raw material, and a general formula ZnxMyWOz (where Zn is zinc, M is Cs, Rb, K, Na, One or more elements selected from Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.001 ≦ x ≦ 2.0, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) is added to the raw material so that the composition is expressed by the following formula, and this mixture is added in a reducing gas atmosphere, an inert gas atmosphere, or a reducing gas and an inert gas. The near-infrared shielding material according to claim 1, which is heat-treated in a mixed atmosphere of active gas. To produce particles, a plasma display near infrared absorption filter manufacturing method of the panel, characterized in that to obtain the near-infrared-absorbing material particles with the near-infrared-absorbing material fine particle dispersion. In the method for producing a near-infrared absorbing filter for a plasma display panel having a near-infrared absorbing material fine particle dispersion in which near-infrared absorbing material fine particles are dispersed,
General formula MyWOz (where M is one or more elements selected from Cs, Rb, K, Na, Ba, Ca, Sr, Mg, W is tungsten, O is oxygen, 0.1 ≦ y ≦ 0 .5, 2.2 ≦ z ≦ 3.0) as a raw material, and the general formula LixMyWOz (where Li is lithium, M is Cs, Rb, K, Na, One or more elements selected from Ba, Ca, Sr, and Mg, W is tungsten, O is oxygen, 0.0001 ≦ x <0.1, 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) A compound having lithium element is added to the raw material so as to have a composition represented by ≦ z ≦ 3.0), and the mixture is fired in the atmosphere or in an inert gas atmosphere, and then in a reducing gas atmosphere. Or, heat treatment in a mixed atmosphere of reducing gas and inert gas To produce a near-infrared shielding material fine particles according to 3, method for manufacturing a plasma near infrared absorption filter for a display panel, characterized in that to obtain the near-infrared-absorbing material microparticle dispersion with the near-infrared-absorbing material particles.   A near-infrared absorbing material fine particle produced by the method according to claim 10 or 11, a diimonium compound, an aminium compound, a phthalocyanine compound, an organometallic complex, a cyanine compound, an azo compound, a polymethine compound, or a quinone compound. 12. The near-infrared absorbing material fine particle dispersion is obtained by adding at least one organic compound selected from the group consisting of diphenylmethane-based compounds and triphenylmethane-based compounds. Manufacturing method of near-infrared absorbing filter.   A near-infrared absorbing material fine particle produced by the method according to claim 10 or 11 or a coating liquid in which the near-infrared absorbing material fine particle and the organic compound according to claim 12 are dispersed in a liquid medium is used as a plasma display panel. The near-infrared absorbing filter for plasma display panels according to any one of claims 10 to 12, wherein the near-infrared absorbing material fine particle dispersion is formed by coating on the surface of a substrate constituting the near-infrared absorbing filter for use. Production method.   The near-infrared absorbing material fine particles produced by the method according to claim 10 or 11, or the near-infrared absorbing material fine particles and the organic compound according to claim 12 are dispersed in a binder resin and kneaded, and then formed into a board shape or The method for producing a near-infrared absorbing filter for a plasma display panel according to any one of claims 10 to 12, wherein the near-infrared absorbing material fine particle dispersion is formed into a film shape.

Images