Electronic device and LC shutter for polarization-sensitive switching between transparent and diffusive states
View Patent ↗An electronic device ( 200 ) includes a display ( 202 ) and an LC shutter ( 204 ), at least a portion of which is operatively positioned over the display ( 202 ). The LC shutter ( 204 ) provides switching between a transparent state and a diffusive state with high image integrity, and high transmission in the transparent state. In one embodiment, the electronic device ( 200 ) further includes control logic ( 206 ) operatively coupled to the LC shutter ( 204 ) to provide control signals ( 212 ) to the LC shutter ( 204 ) to effect the transparent state. The LC shutter ( 204 ) includes a first dichroic polarizer ( 300 ), such as a broadband dichroic polarizer, a specular reflective polarizer ( 302 ), such as a broadband reflective polarizer, an LC cell ( 304 ), and a diffusive reflective polarizer ( 306 ). The LC cell ( 304 ) is interposed between the first dichroic polarizer ( 300 ) and the specular reflective polarizer ( 302 ). The diffusive reflective polarizer ( 306 ) is interposed between the LC cell ( 304 ) and the specular reflective polarizer ( 302 ). Related methods are also set forth.
1. An LC shutter comprising:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
wherein a transmission axis of the in-plane anisotropic diffuser and the specular reflective polarizer are aligned with each other.
2. The LC shutter of claim 1 , further comprising a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the in-plane anisotropic diffuser and the specular reflective polarizer, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
3. The LC shutter of claim 1 , further comprising a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the LC cell and the in-plane anisotropic diffuser, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
4. The LC shutter of claim 1 , wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
5. The LC shutter of claim 4 , further comprising a second dichroic polarizer that is a broadband dichroic polarizer, and wherein the LC cell, the in-plane anisotropic diffuser, and the specular reflective polarizer are interposed between the first dichroic polarizer and the second dichroic polarizer.
6. The LC shutter of claim 1 , wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a narrowband specular reflective polarizer.
7. The LC shutter of claim 1 , wherein the in-plane anisotropic diffuser comprises:
a matrix; and
at least one domain dispersed within the matrix;
wherein the in-plane anisotropic diffuser is such that there is a refractive index match between the matrix and the at least one domain along a first axis of the in-plane anisotropic diffuser, and a refractive index mismatch between the matrix and the at least one domain along a second axis of the in-plane anisotropic diffuser, and wherein the first axis and the second axis are substantially in a plane of the in-plane anisotropic diffuser.
8. An LC shutter comprising:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the in-plane anisotropic diffuser and the specular reflective polarizer, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
9. The LC shutter of claim 8 , further comprising a third dichroic polarizer that is a broadband dichroic polarizer, and wherein the LC cell, the in-plane anisotropic diffuser, the second dichroic polarizer, and the specular reflective polarizer are interposed between the first dichroic polarizer and the third dichroic polarizer.
10. An LC shutter comprising:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the LC cell and the in-plane anisotropic diffuser, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
11. The LC shutter of claim 10 , further comprising a third dichroic polarizer that is a broadband dichroic polarizer, and wherein the LC cell, the second dichroic polarizer, the in-plane anisotropic diffuser, and the specular reflective polarizer are interposed between the first dichroic polarizer and the third dichroic polarizer.
12. An electronic device comprising:
a display operative to emit light; and
at least a portion of an LC shutter operatively positioned over the display, and wherein the LC shutter further comprises:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
wherein a transmission axis of the in-plane anisotropic diffuser and the specular reflective polarizer are aligned with each other.
13. The electronic device of claim 12 , further comprising a radio-telephone subsystem operatively coupled to the display.
14. The electronic device of claim 12 , further comprising a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the in-plane anisotropic diffuser and the specular reflective polarizer, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
15. The electronic device of claim 12 , further comprising a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the LC cell and the in-plane anisotropic diffuser, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
16. The electronic device of claim 12 , wherein:
the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer,
the LC shutter further comprises a second dichroic polarizer that is a broadband dichroic polarizer, and
the LC cell, the in-plane anisotropic diffuser, and the specular reflective polarizer are interposed between the first dichroic polarizer and the second dichroic polarizer.
17. The electronic device of claim 12 , wherein at least a portion of the LC shutter is further operatively positioned over a keypad operative to emit light.
18. The electronic device of claim 12 , wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a narrowband specular reflective polarizer.
19. An LC shutter comprising:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a narrowband specular reflective polarizer.
20. The LC shutter of claim 19 , further comprising a second dichroic polarizer that is a broadband dichroic polarizer, and wherein the LC cell, the in-plane anisotropic diffuser, and the specular reflective polarizer are interposed between the first dichroic polarizer and the second dichroic polarizer.
21. An electronic device comprising:
a display operative to emit light;
at least a portion of an LC shutter operatively positioned over the display, and wherein the LC shutter further comprises:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the in-plane anisotropic diffuser and the specular reflective polarizer, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
22. The electronic device of claim 21 , wherein the LC shutter further comprises a third dichroic polarizer that is a broadband dichroic polarizer, and wherein the LC cell, the in-plane anisotropic diffuser, the second dichroic polarizer, and the specular reflective polarizer are interposed between the first dichroic polarizer and the third dichroic polarizer.
23. An electronic device comprising:
a display operative to emit light;
at least a portion of an LC shutter operatively positioned over the display, and wherein the LC shutter further comprises:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
a second dichroic polarizer that is a narrowband dichroic polarizer interposed between the LC cell and the in-plane anisotropic diffuser, and wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a broadband specular reflective polarizer.
24. The electronic device of claim 23 , wherein the LC shutter further comprises a third dichroic polarizer that is a broadband dichroic polarizer, and wherein the LC cell, the second dichroic polarizer, the in-plane anisotropic diffuser, and the specular reflective polarizer are interposed between the first dichroic polarizer and the third dichroic polarizer.
25. An electronic device comprising:
a display operative to emit light;
at least a portion of an LC shutter operatively positioned over the display, and wherein the LC shutter further comprises:
a first dichroic polarizer;
a specular reflective polarizer;
an LC cell interposed between the first dichroic polarizer and the specular reflective polarizer;
an in-plane anisotropic diffuser interposed between the LC cell and the specular reflective polarizer; and
wherein the first dichroic polarizer is a broadband dichroic polarizer and the specular reflective polarizer is a narrowband specular reflective polarizer.
26. The electronic device of claim 25 , wherein the LC shutter further comprises a second dichroic polarizer that is a broadband dichroic polarizer, and wherein the LC cell, the in-plane anisotropic diffuser, and the specular reflective polarizer are interposed between the first dichroic polarizer and the second dichroic polarizer.