Resin sheet and method of producing resin sheet

Patent metadata

Field	Value
Publication number	US-11654601-B2
Application number	US-202017754116-A
Country	US
Kind code	B2
Filing date	Sep 15, 2020
Priority date	Sep 30, 2019
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

Provided is a resin sheet including a plurality of aspheric sections having low variation of thickness precision and high shape precision. A method of producing a resin sheet includes hot press forming a thermoplastic resin film formed using a thermoplastic resin so as to produce a resin sheet including a plurality of aspheric sections that are separated from one another. The hot press forming is performed by increasing the pressing pressure to a final pressing pressure with an average pressure increase rate of 0.1 MPa/s or less at a pressing temperature that is at least 40° C. higher than the glass-transition temperature of the thermoplastic resin.

First claim

The invention claimed is:

1. A method of producing a resin sheet comprising hot press forming a thermoplastic resin film formed using a thermoplastic resin so as to produce a resin sheet including a plurality of aspheric sections that are separated from one another, wherein
the hot press forming is performed by increasing pressing pressure to a final pressing pressure with an average pressure increase rate of 0.1 MPa/s or less at a pressing temperature that is at least 40° C. higher than a glass-transition temperature of the thermoplastic resin.

2. The method of producing a resin sheet according to claim 1 , wherein the pressing pressure is increased to the final pressing pressure at a constant pressure increase rate of 0.1 MPa/s or less.

3. The method of producing a resin sheet according to claim 1 , wherein at least one surface of the aspheric sections has a thickness direction cross-sectional shape that is a shape including an inflection point.

4. A resin sheet formed using a thermoplastic resin and comprising a plurality of aspheric sections, wherein
arrangement density of the aspheric sections is 0.16 sections/cm 2 or more,
minimum spacing between adjacent aspheric sections is 1.0 mm or more,
diameter of the aspheric sections in plan view is not less than 1 mm and not more than 15 mm,
retardation of the aspheric sections is 50 nm or less, and
thickness of a thinnest section is 500 μm or less.

5. The resin sheet according to claim 4 , wherein variation of thickness precision of the aspheric sections is 0.2 μm or less.

6. The resin sheet according to claim 4 , wherein at least one surface of the aspheric sections has a thickness direction cross-sectional shape that is a shape including an inflection point.

Assignees

• Zeon Corp

Inventors

• Sawaguchi Taichi
• Sudeji Hironari

Classifications

• B29C43/222 Primary

  characterised by the shape of the surface · CPC title

• B29C2043/5808

  pressure or compressing force · CPC title

• G02B2003/0093

  characterised by the shape · CPC title

• B29K2901/12

  Thermoplastic materials · CPC title

• B29D11/00298 Primary

  Producing lens arrays · CPC title