Multilayer stack with overlapping harmonics for wide visible-infrared coverage

• US 9,678,252 B2
• Filed: 02/19/2016
• Issued: 06/13/2017
• Est. Priority Date: 04/19/2013
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Weber, Michael F., Nevitt, Timothy J., Kivel, Edward J.
• Primary Examiner(s): Chapel, Derek S
• Application Number:
  US15/048,077
• Publication Number:
  US 20160170101A1
• Time in Patent Office: 480 Days
• Field of Search: None
• CPC Class Codes: G02B 5/0816 Multilayer mirrors, i.e. having two or more reflecting layers G02B5/0883, G02B5/0891 take precedence
• CPC Class Codes: G02B 5/0841 comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 5/26 Reflecting filters G02B5/28 takes precedence
• CPC Class Codes: G02B 5/281 designed for the infrared light
• CPC Class Codes: G02B 5/287 comprising at least one layer of organic material
• CPC Class Codes: G02B 5/3041 comprising multiple thin layers, e.g. multilayer stacks

Abstract

A broadband mirror, polarizer, or other reflector includes at least one stack of microlayers. Microlayers in the stack are arranged into optical repeat units. At a design angle of incidence such as normal incidence, the stack provides a 1^st order reflection band, a 2^nd order reflection band, and optionally a 3^rd order reflection band. The 2^nd order reflection band overlaps, or substantially overlaps, the 1^st and/or 3^rd order reflection bands to form a single wide reflection band. The wide reflection band may include the 2^nd and 1^st but not a 3^rd order reflection band, or the 2^nd and 3^rd but not the 1^st order reflection band, or it may include the 1^st, 2^nd, and 3^rd order reflection bands, as well as still higher order reflection bands. The wide reflection band may cover at least a portion of visible and infrared wavelengths.

Claims

1. A mirror film composed of a multilayer optical film comprising a stack of microlayers arranged into optical repeat units;

wherein, at a design angle of incidence, the stack provides a 1^st order reflection band, a 2^nd order reflection band, and optionally a 3^rd order reflection band;

wherein the 1^st order reflection band is disposed at least partially in a wavelength range from 720 to 2000 nm;

wherein the 2^nd order reflection band is disposed at least partially in a wavelength range from 380 to 720 nm;

wherein the 2^nd order reflection band substantially overlaps at least one of the 1^st and 3^rd order reflection bands to form a single wide reflection band; and

wherein the single wide reflection band is associated with orthogonal polarization states.

2. The film of claim 1, wherein the 2^nd order reflection band substantially overlaps the 1^st order reflection band, such that the single wide reflection band includes the 1^st and 2^nd order reflection bands.

3. The film of claim 2, wherein the stack does not provide the 3^rd order reflection band.

4. The film of claim 2, wherein the stack provides the 3^rd order reflection band.

5. A polarizer film composed of a multilayer optical film comprising a stack of microlayers arranged into optical repeat units;

wherein, at a design angle of incidence, the stack provides a 1^st order reflection band, a 2^nd order reflection band, and optionally a 3^rd order reflection band;

wherein the 1^st order reflection band is disposed at least partially in a wavelength range from 720 to 2000 nm;

wherein the 2^nd order reflection band is disposed at least partially in a wavelength range from 380 to 720 nm;

wherein the 2^nd order reflection band substantially overlaps at least one of the 1^st and 3^rd order reflection bands to form a single wide reflection band; and

wherein the single wide reflection band is associated with only one polarization state.

6. The film of claim 5, wherein the 2^nd order reflection band substantially overlaps the 1^st order reflection band, such that the single wide reflection band includes the 1^st and 2^nd order reflection bands.

7. The film of claim 6, wherein the stack does not provide the 3^rd order reflection band.

8. The film of claim 6, wherein the stack provides the 3^rd order reflection band.

9. A multilayer optical film comprising a stack of microlayers arranged into optical repeat units;

wherein, at a design angle of incidence, the stack provides a 1^st order reflection band, a 2^nd order reflection band, and optionally a 3^rd order reflection band;

wherein the 1^st order reflection band is disposed at least partially in a wavelength range from 720 to 2000 nm;

wherein the 2^nd order reflection band is disposed at least partially in a wavelength range from 380 to 720 nm;

wherein the 2^nd order reflection band substantially overlaps at least one of the 1^st and 3^rd order reflection bands to form a single wide reflection band; and

wherein the single wide reflection band includes an abrupt step change in reflectivity and transmission in the 1^st order reflection band.

10. The film of claim 9, wherein a portion of the 2^nd order reflection band has a lower reflectivity than the 1^st order reflection band.

11. The film of claim 9, wherein the 2^nd order reflection band substantially overlaps the 1^st order reflection band, such that the single wide reflection band includes the 1^st and 2^nd order reflection bands.

12. The film of claim 11, wherein the stack does not provide the 3^rd order reflection band.

13. The film of claim 11, wherein the stack provides the 3^rd order reflection band.