Optical systems

Patent metadata

Field	Value
Publication number	US-12007595-B2
Application number	US-202118254437-A
Country	US
Kind code	B2
Filing date	Nov 16, 2021
Priority date	Dec 14, 2020
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

An optical assembly includes an integral lens assembly having one or more lenses bonded to each other with spaced apart major first and second lens surfaces. First and second optical films are bonded to respective major first and second lens surfaces. The first and second optical films includes a plurality of polymeric layers. Each of the polymeric layers have an average thickness of less than about 500 nm. For a substantially normally incident light and a visible wavelength range the plurality of polymeric layers in the first optical film has an average optical transmittance and an average optical reflectance of greater than about 70% for a first polarization state and an orthogonal second polarization state, respectively. The plurality of polymeric layers in the second optical film has an average optical transmittance of greater than about 70% for at least one of the first and second polarization states.

First claim

The invention claimed is:

1. An optical assembly comprising:
an integral lens assembly comprising one or more lenses bonded to each other and comprising spaced apart major first and second lens surfaces; and
first and second optical films bonded to the respective major first and second lens surfaces, each of the first and second optical films comprising a plurality of polymeric layers numbering at least 10 in total, each of the polymeric layers having an average thickness of less than about 500 nm, such that for a substantially normally incident light and a visible wavelength range extending from about 420 nm to about 680 nm:
the plurality of polymeric layers in the first optical film has an average optical transmittance of greater than about 70% for a first polarization state and an average optical reflectance of greater than about 70% for an orthogonal second polarization state in the visible wavelength range; and
the plurality of polymeric layers in the second optical film has an average optical transmittance of greater than about 70% for at least one of the first and second polarization states in the visible wavelength range,
wherein the first and second optical films have respective average thicknesses T 1 and T 2 , respective elastic stiffnesses Q 1 and Q 2 in a same first direction, respective thermal strains E 1 and E 2 in a same second direction, and respective coefficients of thermal expansion A 1 and A 2 in a same third direction, the third direction being within 20 degrees of the first direction, wherein:
products Q 1 ×T 1 ×E 1 and Q 2 ×T 2 ×E 2 are within 20% of each other, and/or
products Q 1 ×T 1 ×A 1 and Q 2 ×T 2 ×A 2 are within 20% of each other.

2. The optical assembly of claim 1 , wherein the plurality of polymeric layers in the second optical film has an average optical transmittance of greater than about 70% for each of the first and second polarization states in the visible wavelength range.

3. The optical assembly of claim 1 , wherein for at least one wavelength less than about 400 nm, the plurality of polymeric layers in the second optical film has an average optical transmittance of greater than about 60% for the first polarization state and an average optical reflectance of greater than about 60% for the second polarization state, and wherein for at least one wavelength greater than about 750 nm, the plurality of polymeric layers in the second optical film has an average optical transmittance of greater than about 60% for the first polarization state and an average optical reflectance of greater than about 60% for the second polarization state.

4. The optical assembly of claim 1 , wherein for at least one of the first and second polarization states, the plurality of polymeric layers of at least one of the first and second optical films has an average optical absorption of less than about 20% in the visible wavelength range.

5. An optical system for displaying an image to a viewer, comprising:
a display adapted to emit an image;
the optical assembly of claim 1 ;
a first retarder layer disposed between the optical assembly and the display;
a display lens disposed between the first retarder layer and the display; and
a partial reflector disposed on and conforming to a major surface of the display lens and having an average optical reflectance of at least 30% in the visible wavelength range.

6. An optical assembly comprising:
a polymeric optical lens comprising opposing major first and second lens surfaces, at least one of the first and second lens surfaces curved; and
first and second polymeric optical films bonded to the respective major first and second lens surfaces, the first and second polymeric optical films having respective average thicknesses T 1 and T 2 , respective elastic stiffnesses Q 1 and Q 2 in a same first direction, and respective thermal strains E 1 and E 2 in a same second direction, wherein the second polymeric optical film is a reflecting polarizing film and the first polymeric optical film is a mechanical balancing film such that products Q 1 ×T 1 ×E 1 and Q 2 ×T 2 ×E 2 are within 20% of each other.

7. The optical assembly of claim 6 , wherein the first and second polymeric optical films have respective coefficients of thermal expansion A 1 and A 2 in a same third direction, and wherein products Q 1 ×T 1 ×A 1 and Q 2 ×T 2 ×A 2 are within 20% of each other, and wherein the first and third directions are within 20 degrees of each other.

8. An optical assembly comprising:
a polymeric optical lens comprising opposing major first and second lens surfaces, at least one of the first and second lens surfaces curved; and
first and second polymeric optical films bonded to the respective major first and second lens surfaces, the first and second polymeric optical films having respective average thicknesses T 1 and T 2 , respective elastic stiffnesses Q 1 and Q 2 in a same first direction, and respective coefficients of thermal expansion A 1 and A 2 in a same second direction, wherein the second polymeric optical film is a reflecting polarizing film and the first polymeric optical film is a mechanical balancing film such that products Q 1 ×T 1 ×A 1 and Q 2 ×T 2 ×A 2 are within 20% of each other.

9. The optical assembly of claim 8 , wherein for a substantially normally incident light, each of the first and second polymeric optical films has an average optical transmittance of greater than about 70% for at least a first polarization state in a visible wavelength range extending from about 420 nm to about 650 nm.

10. The optical assembly of claim 8 , wherein the first and second polymeric optical films have respective thermal strains E 1 and E 2 in a same third direction, and wherein products Q 1 ×T 1 ×E 1 and Q 2 ×T 2 ×E 2 are within 20% of each other, and wherein the first and third directions are within 20 degrees of each other.

Assignees

• 3M Innovative Properties Company

Inventors

• Le John D
• Ambur Gregg A
• Yun Zhisheng
• Jennings Robert M
• Kotz Arthur L
• Wong Timothy L
• Yust David T
• Nevitt Timothy J
• Mcgrath Kayla A

Classifications

• G02B1/041

  Lenses · CPC title

• G02B5/305 Primary

  including organic materials, e.g. polymeric layers · CPC title