Optical system
An optical system includes an optical cavity defined by a reflective polarizer and a partial reflector. The optical cavity includes one or more optical components including a first optical lens spaced apart from the reflective polarizer. Each optical component within the optical cavity has a substantially uniform retardance or a maximum retardance of less than about 10 nm. The optical system includes a second optical lens disposed outside the optical cavity. The reflective polarizer is disposed on and conforms to a major surface of the second optical lens. The second optical lens has a substantially nonuniform retardance and a maximum retardance in a largest active region of the second optical lens of greater than about 12 nm.
1 . An optical system comprising:
an optical cavity defined by a reflective polarizer and a partial reflector, the reflective polarizer substantially reflecting light having a first polarization state in a predetermined wavelength range and substantially transmitting light having an orthogonal second polarization state in the predetermined wavelength range, the partial reflector having an average optical reflectance of at least 20% in the predetermined wavelength range, the optical cavity comprising one or more optical components including a first optical lens spaced apart from the reflective polarizer, each optical component within the optical cavity having a substantially uniform retardance or a maximum retardance of less than about 10 nm; and
a second optical lens disposed outside the optical cavity, the reflective polarizer disposed on and conforming to a major surface of the second optical lens, the second optical lens having a substantially nonuniform retardance and a maximum retardance in a largest active region of the second optical lens of greater than about 12 nm, the second optical lens configured to face a display.
2 . The optical system of claim 1 , wherein the one or more optical components comprises a retarder disposed on a major surface of the first optical lens.
3 . The optical system of claim 2 , wherein for a circularly polarized light substantially normally incident on a side of the retarder opposite the first optical lens at an incident location, and for each incident location such that the light is transmitted through a largest active region of the first optical lens without being transmitted through any portion of the first optical lens outside the largest active region of the first optical lens, a degree of linear polarization of the transmitted light is greater than 0.95.
4 . The optical system of claim 1 , wherein for a linearly polarized light substantially normally incident on a major surface of the second optical lens at a first incident location such that the light is transmitted through the largest active region of the second optical lens without being transmitted through any portion of the second optical lens outside the largest active region of the second optical lens, a degree of linear polarization of the transmitted light is less than 0.93.
5 . The optical system of claim 1 , wherein when the first optical lens is disposed between crossed first and second linear polarizers having respective mutually orthogonal first and second pass axes and a light polarized along the first pass axis and having an intensity I 0 is incident on the first linear polarizer such that the light is transmitted through the first linear polarizer and is incident on the first optical lens at an incident location, and for each incident location such that the light is transmitted through a largest active region of the first optical lens without being transmitted through any portion of the first optical lens outside the largest active region of the first optical lens, an intensity of light transmitted through the second linear polarizer is less than about 0.008 I 0 .
6 . The optical system of claim 1 , wherein when the first optical lens is disposed between crossed first and second linear polarizers having respective mutually orthogonal first and second pass axes and a light polarized along the first pass axis and having an intensity I 0 is incident on the first linear polarizer such that the light is transmitted through the first linear polarizer and is incident on the second optical lens at an incident location, and for at least one incident location such that the light is transmitted through a largest active region of the second optical lens without being transmitted through any portion of the second optical lens outside the largest active region of the second optical lens, an intensity of light transmitted through the second linear polarizer is greater than about 0.01 I 0 .
7 . The optical system of claim 1 , wherein the first optical lens has a maximum retardance in a largest active region of the first optical lens of less than about 8 nm, and wherein the maximum retardance in the largest active region of the second optical lens is greater than about 14 nm.
8 . The optical system of claim 1 , wherein no optical lenses are disposed between the first and second optical lenses.
9 . The optical system of claim 1 further comprising an absorbing linear polarizer, the partial reflector disposed between the absorbing linear polarizer and the first optical lens.
10 . The optical system of claim 9 , further comprising a retarder disposed between the absorbing linear polarizer and the partial reflector.
11 . The optical system of claim 1 , wherein the first and second optical lenses are bonded to one another through an adhesive layer disposed between the first optical lens and the reflective polarizer.
12 . The optical system of claim 1 , wherein the second optical lens comprises at least one of polycarbonate, polystyrene, polyester, amorphous polyolefin, or styrene methyl methacrylate.
13 . An optical system comprising:
first and second optical lenses, the first optical lens comprising a first major surface facing the second optical lens and an opposite second major surface, the second optical lens comprising a first major surface and an opposite second major surface facing and concave towards the first optical lens, the first and second optical lenses having respective first and second maximum retardances in largest active regions of the respective first and second optical lenses, the first maximum retardance being less than about 10 nm, the second maximum retardance being at least about 2 nm greater than the first maximum retardance;
a reflective polarizer disposed on and conforming to the second major surface of the second optical lens, the reflective polarizer substantially reflecting light having a first polarization state in a predetermined wavelength range and substantially transmitting light having an orthogonal second polarization state in the predetermined wavelength range; and
a partial reflector disposed on the second major surface of the first optical lens, the partial reflector having an average optical reflectance of at least 20% in the predetermined wavelength range.
14 . The optical system of claim 13 further comprising a display, the second optical lens disposed between the display and the first optical lens, the first major surface of the second optical lens facing the display.
15 . The optical system of claim 13 further comprising a retarder disposed between the partial reflector and the first optical lens.
16 . The optical system of claim 13 , wherein no optical lenses are disposed between the first and second optical lenses.
17 . The optical system of claim 13 further comprising an absorbing linear polarizer, the partial reflector disposed between the absorbing linear polarizer and the second major surface of the first optical lens.
18 . The optical system of claim 17 , further comprising a retarder disposed between the absorbing linear polarizer and the partial reflector.
19 . The optical system of claim 13 , wherein the first and second optical lenses are bonded to one another through an adhesive layer disposed between the first major surface of the first optical lens and the reflective polarizer.
20 . The optical system of claim 13 , wherein the second optical lens comprises at least one of polycarbonate, polystyrene, polyester, amorphous polyolefin, or styrene methyl methacrylate.