Mold and process for production of mold

Patent metadata

Field	Value
Publication number	US-9405043-B2
Application number	US-201113643632-A
Country	US
Kind code	B2
Filing date	Apr 1, 2011
Priority date	Apr 28, 2010
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

A mold manufacturing method of an embodiment of the present invention includes the steps of: (a) providing a mold base; (b) partially anodizing the aluminum layer to form a porous alumina layer, the porous alumina layer having a porous layer which defines a plurality of minute recessed portions and a barrier layer which is provided at a bottom of each of the plurality of minute recessed portions; and (c) after step (b), performing etching, thereby enlarging the plurality of minute recessed portions of the porous alumina layer, wherein in step (c) the etching is performed such that an average depth of the plurality of minute recessed portions increases but does not exceed a 1/7 of an average thickness of the barrier layer before the etching.

First claim

The invention claimed is:

1. A method for manufacturing a mold which has an inverted moth-eye structure over its surface, the inverted moth-eye structure having a plurality of recessed portions whose two-dimensional size viewed in a direction normal to its surface is not less than 10 nm and less than 500 nm, the method comprising the steps of:
(a) providing a mold base, the mold base including a base, an inorganic underlayer, made of an inorganic oxide or an inorganic nitride, provided on the base, a buffer layer, containing aluminum and either of oxygen or nitrogen, provided on the inorganic underlayer, and an aluminum layer provided on the buffer layer;
(b) partially anodizing the aluminum layer to form a porous alumina layer, the porous alumina layer having a porous layer which defines a plurality of minute recessed portions and a barrier layer which is provided at a bottom of each of the plurality of minute recessed portions; and
(c) after step (b), bringing the porous alumina layer into contact with an etching solution to perform etching, thereby enlarging the plurality of minute recessed portions of the porous alumina layer,
wherein in step (c) the etching is performed such that an average depth of the plurality of minute recessed portions increases but does not exceed a 1/7 of an average thickness of the barrier layer before the etching.

2. The method of claim 1 , wherein in step (c) the average thickness of the barrier layer before the etching is not less than 5 nm and not more than 250 nm.

3. The method of claim 2 , wherein in step (c) the average thickness of the barrier layer before the etching is not less than 5 nm and not more than 180 nm.

4. The method of claim 3 , wherein in step (c) the average thickness of the barrier layer before the etching is not less than 85 nm and not more than 95 nm.

5. The method of claim 4 , wherein in step (c) an increase of the average depth is not less than 5 nm and not more than 12 nm.

6. The method of claim 1 , further comprising the step of:
(d) after step (c), further anodizing the aluminum layer to grow the plurality of minute recessed portions.

7. The method of any of claim 1 , wherein in step (c) a phosphoric acid aqueous solution is used as the etching solution.

8. The method of claim 1 , wherein in step (a) the buffer layer includes an aluminum oxide layer.

9. The method of claim 8 , wherein the aluminum oxide layer is formed by sputtering of aluminum in an oxygen atmosphere.

10. A mold which is manufactured according to the manufacturing method as set forth in claim 1 , wherein the porous alumina layer has the inverted moth-eye structure over its surface.

11. An antireflection film which is produced using the mold as set forth in claim 10 , the antireflection film having a surface which is provided with a moth-eye structure.

Assignees

• Isurugi Akinobu
• Minoura Kiyoshi
• Hayashi Hidekazu
• Nakamatsu Kenichiro
• Sharp Kk

Inventors

• Isurugi Akinobu
• Minoura Kiyoshi
• Hayashi Hidekazu
• Nakamatsu Kenichiro

Classifications

• B29C33/56

  Coatings {, e.g. enameled or galvanised}; Releasing, lubricating or separating agents {(in-mould coating B29C37/0028; using or applying separating agents B29C37/0067)} · CPC title

• B29D11/0048

  Moulds for lenses (moulds for plastic articles in general B29C33/00) · CPC title

• C25D11/24

  Chemical after-treatment · CPC title

• B29C33/424

  Moulding surfaces provided with means for marking or patterning (for injection moulding B29C45/372) · CPC title

• C23F1/04

  Chemical milling · CPC title