Methods for testing durable optical elements

• US 7,289,202 B2
• Filed: 09/10/2004
• Issued: 10/30/2007
• Est. Priority Date: 09/10/2004
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Groess, Michael S., Pankratz, Stephan J.
• Primary Examiner(s): Rosenberger; Richard A.
• Application Number:
  US10/938,006
• Publication Number:
  US 20060055918A1
• Time in Patent Office: 1,145 Days
• Field of Search: 356/626, 356/237.1, 356/239.1, 356/239.2
• US Class Current: 356/239.2
• CPC Class Codes: G01N 21/898 Irregularities in textured or patterned surfaces, e.g. textiles, wood

Abstract

A method includes providing a polymerized optical film structure having a microstructured surface, forming a scratch having a length on the microstructured surface to form a scratched optical film, illuminating the scratched optical film to form an illuminated scratch, measuring a plurality of scratch contrast ratio values along the length of the illuminated scratch with a detector, and determining a maximum scratch contrast ratio from the plurality of scratch contrast ratio values along the length of the scratch.

Claims

1. A method comprising:

providing a polymerized optical film structure having a microstructured surface;

forming a scratch having a length on the microstructured surface to form a scratched optical film;

illuminating the scratched optical film to form an illuminated scratch;

measuring a plurality of scratch contrast ratio values along the length of the illuminated scratch with a detector; and

determining a maximum scratch contrast ratio from the plurality of scratch contrast ratio values along the length of the scratch.

2. A method according to claim 1, wherein the illuminating step comprises illuminating the scratched optical film with a backlight.

3. A method according to claim 1, wherein the illuminating step comprises rotating the scratched optical film to obtain an illuminated scratch having a maximum scratch contrast ratio.

4. A method according to claim 1, wherein the illuminating step comprises rotating the scratched optical film from 1 to 89 degrees off axis to obtain an illuminated scratch having a maximum scratch contrast ratio.

5. A method according to claim 1, wherein the illuminating step comprises rotating the scratched optical film from 20 to 70 degrees off axis to obtain an illuminated scratch having a maximum scratch contrast ratio.

6. A method according to claim 1, wherein the illuminating step comprises rotating the scratched optical film from 35 to 60 degrees off axis to obtain an illuminated scratch having a maximum scratch contrast ratio.

7. A method according to claim 1, wherein the determining step comprises integrating and normalizing the plurality of scratch contrast ratio values along the length of the scratch.

8. A method according to claim 1, wherein the providing step comprises providing a polymerized optical film structure having a microstructured prismatic surface.

9. A method comprising:

providing a plurality of polymerized optical film structures having a microstructured surface, wherein each optical film is different;

forming a scratch having a length on each of the microstructured surface to form a scratched optical film, wherein each scratch is formed with a first set of scratch forming parameters;

illuminating each of the scratched optical films to form an illuminated scratch on each scratched optical film;

measuring a plurality of scratch contrast ratio values along the length of each illuminated scratch with a detector; and

determining a maximum scratch contrast ratio from the plurality of scratch contrast ratio values along the length of the scratch for each optical film.

10. A method according to claim 9, wherein the illuminating step comprises illuminating each of the scratched optical films with a backlight.

11. A method according to claim 9, wherein the illuminating step comprises rotating each of the scratched optical films to form an illuminated scratch on each scratched optical film.

12. A method according to claim 9, wherein the illuminating step comprises rotating each of the scratched optical films from 1 to 89 degrees off axis to form an illuminated scratch on each scratched optical film.

13. A method according to claim 9, wherein the illuminating step comprises rotating each of the scratched optical films from 20 to 70 degrees off axis to form an illuminated scratch on each scratched optical film.

14. A method according to claim 9, wherein the illuminating step comprises rotating each of the scratched optical film from 35 to 60 degrees off axis to form an illuminated scratch on each scratched optical film.

15. A method according to claim 9, wherein the determining step comprises integrating and normalizing the plurality of scratch contrast ratio values along the length of the scratch for each optical film.

16. A method according to claim 9, further comprising a step of comparing the maximum scratch contrast ratio for each of the optical films to determine a relative durability of each optical film.