Optical system

Patent metadata

Field	Value
Publication number	US-11262565-B2
Application number	US-201816495356-A
Country	US
Kind code	B2
Filing date	May 14, 2018
Priority date	May 16, 2017
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

Optical systems for displaying an image are described. The optical systems include spaced apart first and second optical lenses. A partial reflector is disposed on and conforms to a major surface of the first optical lens where the major surface can have a best-fit spherical radius of curvature in a range from 20 mm to 200 mm. A reflective polarizer is disposed on and conforms to a major surface of the second optical lens where the major surface can have a best-fit spherical radius of curvature in a range from 14 mm to 250 mm. A retarder layer is disposed between the reflective polarizer and the partial reflector. The first optical lens can have an optical birefringence of less than 15 nm/cm and the second optical lens can have an optical birefringence of greater than 15 nm/cm. A method of fabricating an optical assembly is described.

First claim

What is claimed is:

1. An optical system for displaying an image to a viewer comprising:
a first optical lens comprising an optical birefringence less than about 15 nm/cm, a curved first major surface having a best-fit spherical first radius of curvature in a range from about 20 mm to about 200 mm, and an opposing second major surface having a best-fit spherical second radius of curvature greater than about 500 mm, the curved first major surface concave toward the second major surface;
a second optical lens comprising an optical birefringence greater than about 15 nm/cm, a curved first major surface facing and convex toward the second major surface of the first optical lens and having a best-fit spherical first radius of curvature in a range from about 14 mm to about 250 mm, and an opposing second major surface having a best-fit spherical second radius of curvature greater than about 125 mm;
a partial reflector disposed on and conforming to the first curved major surface of the first optical lens and having an average optical reflectance of at least 30% in a predetermined wavelength range;
a reflective polarizer disposed on and conforming to the curved first major surface of the second optical lens, the reflective polarizer substantially reflecting light having a first polarization state and substantially transmitting light having an orthogonal second polarization state in the predetermined wavelength range; and
a first retarder layer disposed on and conforming to the second major surface of the first optical lens.

2. The optical system of claim 1 , wherein the curved first major surface of the first optical lens is an aspherical surface described by a formula:

z
=

cr
2

1
+

[

1
-

(

1
+
k

)

⁢

c
2

⁢

r
2

]

1
/
2

+

Dr
2

+

Er
4

+

Fr
6

+

Gr
8

+

Hr
10

+

Ir
12

+

Jr
14

where r is a distance from an optical axis of the optical system to the aspherical surface, c is a curvature coefficient, k is a conic constant and D, E, F, G, H, I and J are correction coefficients of the aspherical surface, wherein k is about 4.6, c is about 1/44.9 mm −1 , D is about zero, E is about −1.3E-06, F is about 6E-09 and G is about −1.6E-12.

3. The optical system of claim 1 , wherein the curved first major surface of the second optical lens is an aspherical surface described by a formula:

z
=

cr
2

1
+

[

1
-

(

1
+
k

)

⁢

c
2

⁢

r
2

]

1
/
2

+

Dr
2

+

Er
4

+

Fr
6

+

Gr
8

+

Hr
10

+

Ir
12

+

Jr
14

where r is a distance from an optical axis of the optical system to the aspherical surface, c is a curvature coefficient, k is a conic constant and D, E, F, G, H, I and J are correction coefficients of the aspherical surface, wherein k is about 4.9, c is about 1/120 mm −1 , D is about zero, E is about 2.5E-06, F is about zero and G is about zero.

4. The optical system of claim 1 , wherein the second major surface of the second optical lens is an aspherical surface described by a formula:

z
=

cr
2

1
+

[

1
-

(

1
+
k

)

⁢

c
2

Assignees

• 3M Innovative Properties Co
• 3M Innovatipve Properties C Ompany

Inventors

• Etter Jo A
• Wong Timothy L
• Yun Zhisheng
• Ambur Gregg A
• Sonnek Benjamin G
• Jennings Robert M

Classifications

• G02B5/305

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

• G02B25/001

  Eyepieces · CPC title

• G02B3/00

  Simple or compound lenses · 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

• G02B5/3025

  Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence) · CPC title