Light absorption antireflective body and method of producing the same

• US 6,344,288 B1
• Filed: 08/24/2000
• Issued: 02/05/2002
• Est. Priority Date: 02/24/1998
• Status: Expired due to Fees

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Yamada, Tomohiro, Oyama, Takuji
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): Piziali, Andrew T.
• Application Number:
  US09/622,056
• Time in Patent Office: 530 Days
• Field of Search: 428/325, 428/327, 428/336, 428/701, 428/702, 428/432, 204/192.1, 427/535
• US Class Current: 428/701
• CPC Class Codes: G02B 1/116 including electrically conducting layers
• CPC Class Codes: H01J 2229/8918 by using interference effects
• CPC Class Codes: H01J 29/896 Anti-reflection means, e.g. eliminating glare due to ambient light
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/254 Polymeric or resinous material
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

A light absorptive antireflector comprising a substrate, and a first layer of a light absorptive film, a second layer made of a material which has slight absorption within a visible light region and a third layer made of a material which has a refractive index smaller than 1.55, sequentially formed on the substrate, which has an adequate low reflection performance within a wide range of a wavelength region and which has an electromagnetic shielding ability and a low luminous transmittance suitable for improving the contrast of a display, has freeness in transmittance and reflection color and is excellent also in the productivity, and a method for its production.

Claims

1. A light absorptive antireflector comprising:

a substrate;

a first layer of a light absorptive film;

a second layer made of a material that has slight absorption within a wavelength range of 400 to 700 nm, has an extinction coefficient being larger on a short wavelength side, within a wavelength range of 400 to 700 nm, and has an extinction coefficient in the range of 0.05 to 0.6, at a wavelength of 400 nm; and

a third layer made of a material that is transparent within a wavelength range of 400 to 700 nm and has a refractive index of less than 1.55, wherein the layers are formed sequentially on the substrate.

2. The light absorptive antireflector according with claim 1, wherein the second layer is made of a material that has a refractive index of at least 1.8.

3. The light absorptive antireflector according with claim 1, wherein the second layer is made of a material containing silicon nitride as the main component, a material containing bismuth oxide as the main component or a material containing chromium oxide as the main component.

4. The light absorptive antireflector according with claim 1, wherein the first layer is made of a material containing a nitride of at least one metal selected from the group consisting of titanium, zirconium and hafnium, as the main component.

5. The light absorptive antireflector according with claim 1, wherein the third layer is made of a material containing silicon and oxygen.

6. The light absorptive anti reflector according with claim 1, wherein the geometrical film thickness of the first layer is from 5 to 40 nm, the geometrical film thickness of the second layer is from 2 to 40 nm, and the geometrical film thickness of the third layer is from 40 to 100 nm.

7. The light absorptive antireflector according with claim 1, which has a layer containing aluminum nitride or transparent silicon nitride as the main component between the second layer and the third layer.

8. The light absorptive antireflector according with claim 1, wherein the light absorptivity of the light absorptive antireflector, within a wavelength range of 400 to 700 nm, is from 30 to 65%.

9. The light absorptive antireflector according with claim 1, wherein the reflectance of incident light from the third layer side is at most 0.6%, within a wavelength range of 500 to 650 nm.

10. The light absorptive antireflector according with claim 1, wherein the substrate is a glass substrate, a plastic substrate or a plastic film constituting a front surface of a display panel.

11. The light absorptive antireflector according with claim 1, which has a layer containing silicon nitride as the main component between the substrate and the first layer, wherein the substrate is made of an organic material.

12. A method for producing a light absorptive antireflector, comprising:

applying a plasma treatment to a substrate made of an organic material;

forming a first layer of a light absorptive film on the substrate after the applying step;

forming on the first layer a second layer made of a material which has slight absorption, within a wavelength range of 400 to 700 nm, and an extinction coefficient being larger on a short wavelength side within a wavelength range of 400 to 700 nm; and

forming on the second layer a third layer made of a material which is transparent within a wavelength range of 400 to 700 nm and has a refractive index of less than 1.55.

13. The method according to claim 12, wherein the plasma treatment is carried out by setting the substrate in a vacuum chamber and then applying a radio frequency electric power to an electrode disposed on the rear side of the substrate for a treating time t (sec) which satisfies the formula, $\frac{2·}{}$

P·

tV·

e·

π

>

5×

1015

where e is an elementary electric charge of 1.6×

10<sup>−

19</sup> (C), P is the electric power (W) applied to the substrate surface, and V is the self-bias potential (V) of the electrode.