JP2003121636A - Cut filter for near ir ray and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fast form films of a cut filter for near IR rays by sputtering which reflects near IR rays emitting from a PDP and which reflects near IR rays in the sun rays. SOLUTION: The films are deposited by a sputtering method using conductive silicon carbide and conductive titanium oxide as targets.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a near infrared ray cut filter obtained by sputtering a low refractive index layer and a high refractive index layer, a method for producing the same, a plasma display front filter using the same, and an energy saving film. Regarding

[0002]

2. Description of the Related Art Plasma display panel (PDP)
Emits near infrared light having a wavelength of 850 to 1200 nm. Since a remote controller such as a home electric appliance used at home uses near infrared rays of 700 to 1300 nm, there is a problem that the near infrared rays emitted from the PDP malfunctions the remote controller. Therefore, it is necessary to attach a filter that cuts near infrared rays that causes a malfunction to the front surface of the PDP.

The near-infrared cut filter is also used as an energy-saving film for improving the cooling efficiency in the summer when it is used for windows of automobiles and buildings by utilizing the property of cutting the near-infrared rays of sunlight. ing.

As such a near-infrared cut filter, there is known one in which a transparent film of silver or indium oxide is laminated on a substrate (Japanese Patent Laid-Open No. 12-167969). These near infrared cut filters are formed by laminating a high refractive index material and a low refractive index material. A sputtering method is generally used as a method for laminating a high-refractive material and a low-refractive material. This method is often used because it is possible to form a uniform thin layer on the nano-order in a large area.

[0005]

However, these thin films have a very low film formation rate in sputtering and low productivity. In order to increase the film formation rate, two cathodes used in recent years are lined up, and high-speed sputtering is possible by applying an alternating current (dual cathode method).
Is proposed. However, this film forming rate is not sufficiently high for industrialization. In addition, the Si target used when forming the low refractive index thin film is fragile, and there is a problem that cracking occurs when high power is applied.

Therefore, an object of the present invention is to find a method capable of forming a film at a high speed, and to find a strong target that does not crack even when a high power is applied. Furthermore, it aims at obtaining a near-infrared cut filter with good productivity.

[0007]

The present invention provides a near infrared cut filter in which low refractive index films and high refractive index films are alternately laminated on a substrate, and the low refractive index film targets conductive silicon carbide. The near-infrared cut filter is characterized in that the high refractive index film is used and is formed by sputtering using conductive titanium oxide as a target.

By using conductive silicon carbide as a target, high power can be applied without cracking. Furthermore, by using conductive titanium oxide and conductive silicon carbide as targets, the film formation rate can be increased.

In the present invention, the low refractive index film is made of Si,
The high-refractive index film is a compound containing at least one atom selected from the group consisting of C, O and N, and the high refractive index film is a compound containing Ti and O in the near-infrared cut filter.

Further, in the present invention, the low refractive index film is SiC.
x, SiOx, SiNx, SiCxOy, SiCxN
It consists of a silicon compound selected from the group consisting of y, SiOxNy and SiCxOyNz (where x is 0.1 to 3, preferably 0.5 to 2.5, y is 0.1 to 3, and preferably 0.5 to 2.5, z is 0.1 to 3, preferably 0.5 to
2.5), the high refractive index film is TiOt (where t is 0.1 to
3 and preferably 0.5 to 2.5).

A near infrared cut filter having a transmittance of 50% or less for light in the wavelength range of 900 nm to 1100 nm, preferably light in the wavelength range of 850 nm to 1150 nm, and a transmittance of 50% or more for wavelengths of 700 nm or less. preferable.

Further, the present invention is a method for manufacturing a near infrared cut filter comprising alternately laminating a low refractive index film and a high refractive index film on a substrate, and using the low refractive index film as a target, conductive silicon carbide is used. A method for producing a near-infrared cut filter is characterized in that the high-refractive-index film is formed by a sputtering method using a conductive titanium oxide as a target.

A method characterized in that the sputtering method is a magnetron sputtering method is preferable.

Further, it is preferable that the magnetron sputtering method is a dual cathode magnetron sputtering method.

It is preferable that the low refractive index film is formed in a mixed gas atmosphere of an inert gas and a reactive gas.

A method characterized in that the reactive gas is a gas containing oxygen in the molecule is preferable.

The low refractive index film is made of SiCx, SiOx, Si.
Nx, SiCxOy, SiCxNy, SiOxNy, S
It consists of a silicon compound selected from the group consisting of iCxOyNz (where x is 0.1 to 3, preferably 0.5 to 2.
5, y is 0.1 to 3, preferably 0.5 to 2.5, z is 0.1 to 3, preferably 0.5 to 2.5, and the high refractive index film is TiOt (where t is 0.1-3, preferably 0.5
~ 2.5) is preferred.

Further, according to the present invention, in a near-infrared cut filter in which a low refractive index film and a high refractive index film are alternately laminated on a substrate, the low refractive index film is SiCx, SiNx, S.
iCxOy, SiCxNy, SiOxNy, SiCxO
It consists of a silicon compound selected from the group consisting of yNz (where x is 0.1 to 3, preferably 0.5 to 2.5, y
Is 0.1 to 3, preferably 0.5 to 2.5, and z is 0.1.
~ 3, preferably 0.5-2.5), the high refractive index film is T
iOt (where t is 0.1 to 3, preferably 0.5 to 2.
It is in the near infrared cut filter consisting of 5).

The low refractive index film is preferably made of SiCxOy. The present invention also resides in a plasma display front filter using the near infrared cut filter. Furthermore, the present invention is an energy-saving film using the above-mentioned near-infrared cut filter.

The density of the silicon carbide target is 2.
It is preferably 9 g / cm ³ or more.

The silicon carbide target is preferably obtained by sintering a mixture of silicon carbide powder and a non-metal type sintering aid.

At the time of the above-mentioned sputtering, it is preferable that the carbon compound is not deposited in the vacuum chamber and is not mixed in the transparent conductive film during film formation.

At the time of the above-mentioned sputtering, it is preferable that the carbon compound is gasified, exhausted to the outside of the vacuum chamber, does not deposit in the vacuum chamber, and is not mixed into the transparent conductive film during film formation.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below. In the present invention, near-infrared light means a wavelength of visible light or more, that is, 760 nm or more, and
Light having a wavelength of 500 nm or less. The near-infrared cut filter of the present invention does not need to reflect all near-infrared rays, and the transmittance of near-infrared rays emitted from PDP, that is, near-infrared rays from about 850 nm to at least about 1200 nm is 50% or less. I wish I had it.

As the filter of the present invention, light in the wavelength range of 900 nm to 1100 nm, preferably 850 nm
A near-infrared cut filter having a light transmittance of 50% or less in the wavelength range from 1 to 1150 nm and a light transmittance of 50% or more in a wavelength of 700 nm or less is preferable.

FIG. 1 is a diagram showing an example of the near infrared cut filter of the present invention. The near-infrared cut filter of the present invention has a basic structure in which low refractive index films 2 and high refractive index films 3 are alternately laminated on a substrate 1.

The thickness and the number of laminated layers of the low refractive index film and the high refractive index film are arbitrarily designed so as to have the characteristics required for the near infrared cut filter. For example, the first layer Si
CxOy (film thickness 171.1 nm), second layer TiOt (1
00 nm), the third layer SiCxOy (171.1 nm),
Fourth layer TiOt (100 nm), fifth layer SiCxOy
(171.1 nm), sixth layer TiOt (100 nm),
Seventh layer SiCxOy (171.1 nm) (where x =
0.1-3, y = 0.1-3, t = 0.1-3) and is generally obtained at a wavelength of 850 nm.
The characteristic of a near infrared cut filter that reflects light of 1150 nm at a reflectance of 50% or more is obtained.

According to the present invention, the low refractive index film is formed by the sputtering method using conductive silicon carbide as a target. As a result, high power can be applied without cracking. Further, the high refractive index film is formed by a sputtering method using conductive titanium oxide as a target. Therefore, the film forming rate can be increased.

The thickness of each layer does not have to be the same, and is designed arbitrarily according to the required characteristics.

The substrate 1 to be sputtered according to the present invention is
Glass, plastic such as polyester, polyethylene terephthalate (PET), polybutylene terephthalate, polymethylmethacrylate, acrylic, polycarbonate (PC), polystyrene, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion crosslinking Examples thereof include ethylene-methacrylic acid copolymer, polyurethane, and cellophane, and glass and PET are particularly preferable.

The thickness of the substrate may be any thickness so long as it does not interfere with transparency. In the case of PET, it is generally 150 to 200 μm.
m.

When PET is used as a substrate, a hard coat may be laminated thereon to protect the surface of the substrate, and its thickness is generally 4 to 6 μm. Examples of hard coat materials include acrylic resins, epoxy resins, urethane resins, and silicone resins.

The low refractive index film 2 is made of SiCx, SiOx, S.
iNx, SiCxOy, SiCxNy, SiOxNy,
A silicon compound selected from the group consisting of SiCxOyNz (where x is 0.1 to 3, preferably 0.5 to
2.5, y is 0.1 to 3, preferably 0.5 to 2.5,
z is 0.1 to 3, preferably 0.5 to 2.5), and the high refractive index film 3 is made of TiOt (where t is 0.1 to 3, preferably 0.5 to 2.5).

The high refractive index film 3 is obtained by sputtering using conductive titanium oxide as a target. The low refractive index film 2 is obtained by sputtering using conductive silicon carbide as a target.

The conductive titanium oxide target generally means a target having a volume resistivity value of 2E ⁻¹ Ω · cm or less. The conductive silicon carbide target generally means a target having a volume resistivity value of 2E ⁻² Ω · cm or less. By using a conductive titanium oxide target or a conductive silicon carbide target, the film formation rate is increased and the method can be put into practical use.

As the conductive silicon carbide target, silicon carbide powder is used as coal tar pitch, phenol resin,
It is preferable that the density is 2.9 g / cm ³ or more, which is obtained by sintering with a non-metal type sintering aid such as furan resin, epoxy resin, glucose, sucrose, cellulose, starch. With such a high density and uniform target, stable discharge can be performed with high input during sputtering film formation, and the film formation rate can be increased.

By using the conductive silicon carbide target, the carbon compound generated from silicon carbide is gasified in the vacuum chamber and is exhausted out of the vacuum chamber, so that the carbon compound is not deposited in the vacuum chamber and the carbon compound is not formed. There is an advantage that it does not mix with the near infrared cut filter in the film.

The sputtering method used in the present invention is
The magnetron sputtering method is preferred. A dual-cathode magnetron sputtering method can also be used, which makes it possible to perform film formation at a higher speed.

The sputtering conditions such as the supply gas, the supply gas flow rate, the pressure and the supply power can be arbitrarily set in consideration of the target to be used, the film forming rate and the like.

[0040]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Example] For forming a low refractive index layer, a magnetron sputtering device was used as a sputtering device, glass was used as the substrate, and conductive silicon carbide was used as the target material (made by Bridgestone, resistance value 2E ^-2 Ωcm). As the supply gas, argon is 10 cc / min + oxygen gas 3
cc / min, pressure 5 mTorr, power supply 1.2
It was performed under the sputtering conditions of kW.

For forming the high refractive index layer, a magnetron sputtering apparatus is used as a sputtering apparatus, glass is used as a substrate, and conductive titanium oxide (made by Asahi Glass, resistance value: 2E ⁻¹ Ω · cm) is used as a target material and a supply gas. Was 10 cc / min of argon, the pressure was 5 mTorr, and the supply power was 1.2 kW.

[Comparative Example] The low refractive index layer was formed by using a magnetron sputtering device as a sputtering device, glass as the substrate, and Si as the target material.
Supply gas is argon 5 cc / min + oxygen gas 5 cc /
The sputtering was performed under the conditions of min, pressure of 5 mTorr and supply power of 1.2 kW.

The high refractive index layer is formed by using a magnetron sputtering device as a sputtering device, glass as the substrate, Ti as the target material, and the supply gas is argon 5 cc / min + oxygen gas 5 cc / min.
The sputtering was performed under the conditions of a pressure of 5 mTorr and a power supply of 1.2 kW.

A near-infrared cut filter having the layer structure and film thickness shown in Table 1 was prepared. The optical characteristics of the produced filter are shown in FIG.

[0046]

[Table 1] It represents x = 0.8, y = 1.2, and t = 1.9.

As shown in Table 1, in Example 1, a 14-layer near-infrared cut filter can be produced in about 53 minutes, whereas in Comparative Example 1, it takes about 10 and a half hours to form a film. It was Therefore, it was found that the near-infrared cut filter can be produced at high speed by using the method of the present application.

Table 2 under the same conditions as in Example 1 and Comparative Example 1
A near-infrared cut filter was produced with the layer structure and film thickness shown in. The optical characteristics of the produced filter are shown in FIG.

[0049]

[Table 2] It represents x = 0.8, y = 1.2, and t = 1.9.

As shown in Table 2, in Example 2, a seven-layer near-infrared cut filter can be produced in about 30 minutes, whereas in Comparative Example 2, it takes about 5 hours and 50 minutes to form a film. I understood. Therefore, by using the method of the present application,
It was found that a near infrared cut filter can be produced at high speed.

[0051]

INDUSTRIAL APPLICABILITY By sputtering using conductive silicon carbide and conductive titanium oxide as a target, a near-infrared cut filter layer can be stably formed at a high speed on a substrate, and the near-infrared product is rich in productivity. The cut filter can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a near infrared cut filter of the present invention.

FIG. 2 is a graph showing the reflectance (R) and transmittance (T) of the near infrared cut filter of Example 1.

FIG. 3 is a graph showing reflectance (R) and transmittance (T) of the near-infrared cut filter of Example 2.

[Explanation of symbols]

1 substrate 2 Low refractive index film 3 High refractive index film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01J 11/02 G02B 1/10 Z (72) Inventor Yoshinori Iwabuchi 3-1-1 Ogawahigashi-cho, Kodaira-shi, Tokyo F-term (reference) 2H048 FA05 FA07 FA09 FA12 FA24 GA07 GA09 GA11 GA35 GA60 GA61 2K009 BB02 BB13 BB14 BB24 BB25 CC01 CC03 CC42 DD04 EE00 4K029 AA09 AA11 BA41 BA46 BA48 BA54 BA56 BA58 BB02 BC08 BD00 CA06 DC05 DC16 DC39 5C028 AA10 5C040 GH10 MA26

Claims (14)

[Claims] 1. A near-infrared cut filter comprising low refractive index films and high refractive index films alternately laminated on a substrate, wherein the low refractive index film uses conductive silicon carbide as a target, and the high refractive index film is , A near-infrared cut filter formed by sputtering using conductive titanium oxide as a target. 2. The low refractive index film is made of a compound containing Si and at least one atom selected from the group consisting of C, O and N, and the high refractive index film is a compound containing Ti and O. The near-infrared cut filter according to claim 1, which comprises: 3. A low-refractive-index film is formed of SiCx, SiOx, Si.
Nx, SiCxOy, SiCxNy, SiOxNy, S
A high-refractive-index film made of a silicon compound selected from the group consisting of iCxOyNz (where x is 0.1 to 3, y is 0.1 to 3, and z is 0.1 to 3) is TiOt (where t is 0.
1 to 3), The near infrared cut filter according to claim 1 or 2. 4. The near infrared cut filter according to claim 1, which has a transmittance of 50% or less for light in the wavelength range of 900 to 1100 nm. 5. A method for manufacturing a near-infrared cut filter, which comprises alternately laminating a low refractive index film and a high refractive index film on a substrate, and sputtering the low refractive index film using conductive silicon carbide as a target. A method for producing a near-infrared cut filter, which comprises forming a high refractive index film by a sputtering method using conductive titanium oxide as a target. 6. The method according to claim 5, wherein the sputtering method is a magnetron sputtering method. 7. The method according to claim 6, wherein the magnetron sputtering method is a dual cathode magnetron sputtering method. 8. The method according to claim 5, wherein the low refractive index film is formed in a mixed gas atmosphere of an inert gas and a reactive gas. 9. The method according to claim 8, wherein the reactive gas is a gas containing oxygen in its molecule. 10. A low-refractive-index film is formed of SiCx, SiOx, S.
iNx, SiCxOy, SiCxNy, SiOxNy,
The high refractive index film is made of a silicon compound selected from the group consisting of SiCxOyNz (where x is 0.1 to 3, y is 0.1 to 3 and z is 0.1 to 3), and the high refractive index film is TiOt (where t is 0.
1 to 3), wherein the method according to any one of claims 5 to 9. 11. A near-infrared cut filter comprising low refractive index films and high refractive index films alternately laminated on a substrate,
Low-refractive index film is made of SiCx, SiNx, SiCxOy, S
A silicon compound selected from the group consisting of iCxNy, SiOxNy, and SiCxOyNz (where x is 0.1
.About.3, y is 0.1 to 3, z is 0.1 to 3), and the high-refractive index film is a near-infrared cut filter made of TiOt (where t is 0.1 to 3). 12. The near infrared cut filter according to claim 11, wherein the low refractive index film is made of SiCxOy. 13. A plasma display front filter comprising the near-infrared cut filter according to any one of claims 1 to 4, 11 and 12. 14. An energy-saving film comprising the near infrared cut filter according to any one of claims 1 to 4, 11 and 12.