1. Polyphase filter comprising:
at least two filters, each comprising a series admittance element and a shunt conductance element, each for filtering an input signal to produce a filtered signal at an output;
at least two integrators, each corresponding to one of said filters and coupled to said one of said filters, for integrating said filtered signals, each integrator comprising an operational amplifier having one input signal connected to a fixed reference potential;
wherein an output of each integrator is coupled via an impedance element to an input of an adjacent integrator of said at least two integators.
2. Polyphase filter according to claim 1, wherein an output of one integrator of said at least two integrators is coupled via a conductance element to an input of an above integrator of the at least two integrators.
3. Polyphase filter according to claim 2, wherein an output of said one integrator of said at least two integrators is coupled via a capacitor to an input of a below integrator of said at least two integrators.
4. Polyphase filter according to claim 3, wherein said operational amplifier comprises an amplifier with an admittance element in a feedback path.
5. Polyphase filter according to claim 4, wherein each of said filters comprises a passive element selected from a group consisting of a resistor, an inductor and a capacitor, and wherein each of said amplifiers comprises an operational amplifier.
6. Polyphase filter according to claim 5, wherein a passive element comprises a resistor and a capacitor and wherein said admittance element comprises a capacitor and a conductance element coupled in parallel to each other.
7. Polyphase filter according to claim 6, wherein said polyphase filter comprises at least one signal inversion between said at least two integrators.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A liquid crystal display device, comprising:
a liquid crystal cell;
a collimating polarizer under the liquid crystal cell, the collimating polarizer having a collimating layer and a circular polarizer fixed on the collimating layer;
a backlight under the collimating polarizer;
a diffusing layer over the liquid crystal cell;
a retardation layer over the diffusing layer; and
a linear polarizer over the retardation layer.
2. The device according to claim 1, wherein the circular polarizer has cholesteric liquid crystal.
3. The device according to claim 1, wherein the collimating layer has a condensing pattern and the condensing pattern is one of prism pattern, holographic pattern and micro lens pattern.
4. The device according to claim 3, wherein the micro lens pattern is an array.
5. A liquid crystal display device, comprising:
a liquid crystal cell;
a collimating polarizer under the liquid crystal cell, the collimating polarizer having a collimating layer, a circular polarizer and a transparent substrate between the collimating layer and the circular polarizer;
a backlight under the collimating polarizer;
a diffusing layer over the liquid crystal cell;
a retardation layer over the diffusing layer; and
a linear polarizer over the retardation layer.
6. The device according to claim 5, wherein the transparent substrate has plastic.
7. The device according to claim 1, wherein the diffusing layer is holographic pattern.
8. The device according to claim 1, wherein the liquid crystal cell and the collimating polarizer are attached.
9. The device according to claim 1, wherein the liquid crystal cell includes first and second substrates facing each other and having respective electrodes on inner sides of the first and second substrates, and a liquid crystal layer between the respective electrodes.
10. A method of fabricating an integrated collimating polarizer for a liquid crystal display device, comprising:
providing a first transparent substrate;
coating a cholesteric liquid crystal on the first transparent substrate;
exposing and hardening the cholesteric liquid crystal to form a pitch of the cholesteric liquid crystal;
coating a resin on the cholesteric liquid crystal; and
patterning and hardening the resin to form a collimating layer.
11. The method according to claim 10, further comprising disposing a second transparent substrate on the cholesteric liquid crystal.
12. The method according to claim 10, further comprising forming first and second protection films on the collimating layer and under the cholesteric liquid crystal, respectively.
13. The method according to claim 10, wherein a stamp is used in patterning the resin.
14. The method according to claim 10, wherein embossing is used in patterning the resin.
15. The method according to claim 10, wherein the exposing and hardening are provided using ultraviolet light.
16. The method according to claim 10, wherein the exposing and hardening are provided using heat.
17. A method of fabricating an integrated collimating polarizer for a liquid crystal display device, comprising:
providing a first transparent substrate;
coating a cholesteric liquid crystal on the first transparent substrate;
providing a second transparent substrate on the cholesteric liquid crystal layer;
exposing and hardening the cholesteric liquid crystal to form a pitch of the cholesteric liquid crystal;
coating a resin on the cholesteric liquid crystal; and
patterning and hardening the resin to form a collimating layer.
18. The method according to claim 17, wherein the exposing and hardening are provided using ultraviolet light.
19. The method according to claim 17, wherein the exposing and hardening are provided using heat.
20. The method according to claim 17, further comprising passing the first and second substrates with the cholesteric liquid crystal therebetween through rollers before exposing and hardening the cholesteric liquid crystal.