Mask processing using films with spatially selective birefringence reduction

Patent metadata

Field	Value
Publication number	US-9810930-B2
Application number	US-201615218097-A
Country	US
Kind code	B2
Filing date	Jul 25, 2016
Priority date	Jun 30, 2010
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Certain patternable reflective films are used as masks to make other patterned articles, and one or more initial masks can be used to pattern the patternable reflective films. An exemplary patternable reflective film has an absorption characteristic suitable to, upon exposure to a radiant beam, absorptively heat a portion of the film by an amount sufficient to change a first reflective characteristic to a different second reflective characteristic. The change from the first to the second reflective characteristic is attributable to a change in birefringence of one or more layers or materials of the patternable film. In a related article, a mask is attached to such a patternable reflective film. The mask may have opaque portions and light-transmissive portions. Further, the mask may have light-transmissive portions with structures such as focusing elements and/or prismatic elements.

First claim

The invention claimed is:

1. A method of making a patterned film, comprising:
providing a first film having a first reflective characteristic, the first film also having a first absorption characteristic suitable to, upon exposure to a first radiant beam, absorptively heat a portion of the first film by an amount sufficient to change the first reflective characteristic to a second reflective characteristic by a change in birefringence, and the first film comprises a first blended layer that includes first and second polymer materials separated into distinct first and second phases, respectively, and wherein the change from the first reflective characteristic to the second reflective characteristic is substantially attributable to a change in birefringence of at least one of the first and second polymer materials;
providing a second film having a first detectable characteristic that changes to a different second detectable characteristic upon exposure to a second radiant beam;
directing the first radiant beam preferentially at a second zone rather than a first zone of the first film to change the first reflective characteristic to the second reflective characteristic in the second zone by a change in birefringence so as to convert the first film to a patterned mask; and
using the patterned mask to pattern the second radiant beam, and directing the patterned second radiant beam at the second film to change the first detectable characteristic to the second detectable characteristic at selected portions of the second film.

2. The method of claim 1 , wherein directing the first radiant beam preferentially at the second zone of the first film comprises scanning the first radiant beam over portions of the first film that define the second zone.

3. The method of claim 1 , wherein the first reflective characteristic reflects the second radiant beam more than the second reflective characteristic.

4. The method of claim 1 , wherein the selected portions of the second film correspond to the second zone of the first film.

5. The method of claim 1 , wherein the first reflective characteristic reflects the second radiant beam less than the second reflective characteristic.

6. The method of claim 1 , wherein the selected portions of the second film correspond to portions of the first film other than the second zone.

7. The method of claim 1 , wherein the first and second radiant beams comprise different first and second optical wavelengths, respectively.

8. The method of claim 7 , wherein the first optical wavelength is an infrared optical wavelength, and the second optical wavelength is less than 700 nm.

9. The method of claim 1 , wherein the second film has a second absorption characteristic suitable to, upon exposure to the second radiant beam, absorptively heat a portion of the second film by an amount sufficient to change the first detectable characteristic to the second detectable characteristic.

10. The method of claim 9 , wherein the second film comprises a group of interior layers arranged to selectively reflect light by constructive or destructive interference to provide the first detectable characteristic, and wherein the change from the first detectable characteristic to the second detectable characteristic is substantially attributable to a change in birefringence of at least some of the interior layers.

11. The method of claim 9 , wherein the second film comprises a second blended layer that includes third and fourth polymer materials separated into distinct third and fourth phases, respectively, and wherein the change from the first detectable characteristic to the second detectable characteristic is substantially attributable to a change in birefringence of at least one of the third and fourth polymer materials.

12. The method of claim 1 , wherein the first or second reflective characteristic has a reflectivity for the second radiant beam of at least 90%, or at least 95%, or at least 99%.

13. The method of claim 1 , wherein directing the first radiant beam provides the first film with a first pattern, the method further comprising, after using the patterned mask to pattern the second radiant beam:
directing a third radiant beam at the first film to eliminate at least a portion of the first pattern in the first film.

14. The method of claim 13 , wherein the first and second films are connected in a layered arrangement.

15. The method of claim 13 , wherein the third radiant beam is tailored to render the first film substantially unpatterned.

16. The method of claim 13 , wherein the second reflective characteristic is less reflective than the first reflective characteristic.

17. The method of claim 13 , wherein the second reflective characteristic is more reflective than the first reflective characteristic.

18. A method of making a patterned film, comprising:
providing a patterned mask;
providing a first film having a first reflective characteristic, the first film also having a first absorption characteristic suitable to, upon exposure to a first radiant beam, absorptively heat a portion of the first film by an amount sufficient to change the first reflective characteristic to a second reflective characteristic by a change in birefringence, wherein the first film comprises a blended layer that includes first and second polymer materials separated into distinct first and second phases, respectively; and
using the patterned mask to pattern the first radiant beam, and directing the patterned first radiant beam at the first film to change the first reflective characteristic to the second reflective characteristic by a change in birefringence at selected portions of the first film, and wherein the change from the first reflective characteristic to the second reflective characteristic is substantially attributable to a change in birefringence of at least one of the first and second polymer materials.

19. The method of claim 18 , wherein substantially all of the selected portions of the first film are changed from the first to the second reflective characteristic at a same time.

20. An article, comprising:
a first film having a first reflective characteristic, the first film also having a first absorption characteristic suitable to, upon exposure to a first radiant beam, absorptively heat a portion of the first film by an amount sufficient to change the first reflective characteristic to a second reflective characteristic by a change in birefringence, wherein the first film comprises a blended layer that includes first and second polymer materials separated into distinct first and second phases, respectively, wherein the first and second reflective characteristics comprise first and second diffusely reflective characteristics respectively, and wherein the change from the first reflective characteristic to the second reflective characteristic is substantially attributable to a change in birefringence of at least a portion of the first film; and
a mask attached to the first film.

21. The article of claim 20 , wherein the mask has a useable area, and wherein some portions of the useable area block the first radiant beam and other portions of the useable area transmit the first radiant beam.

22. The article of claim 20 , wherein the mask comprises one or more structured surface features adapted to preferentially redirect the first radiant beam onto selected portions of the first film.

23. The article of claim 22 , wherein the one or more structured surface features include

Assignees

• 3M Innovative Properties Co

Inventors

• Merrill William Ward
• Dunn Douglas S

Classifications

• G11B20/1261

  on films, e.g. for optical moving-picture soundtracks (optical aspect G11B7/0032) · CPC title

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• B05D5/063

  Reflective effect (B05D5/067 takes precedence) · CPC title

• G02B5/285

  comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361) · CPC title

• G02F1/0136

  for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation (G02F1/0353 takes precedence) · CPC title