Method and device for driving liquid crystal on silicon display systems
The present invention discloses a pixel display configuration by providing a voltage controller in each pixel control circuit for controlling the voltage inputted to the pixel electrodes. The controller includes a function of multiplexing the voltage input to the pixel electrodes and also a bit buffering and decoupling function to decouple and flexible change the input voltage level to the pixel electrodes. The rate of DC balancing can be increased to one KHz and higher to mitigate the possibility of DC offset effects and the image sticking problems caused by slow DC balancing rates. This invention further discloses an enabling technology for switching from one DC balance state to another without rewriting the data onto the panels. Therefore, it is not required to implement a high voltage CMOS designs and standard CMOS technologies can be applied to manufacture the storage cells and control panel for the LCOS displays with lower production cost and higher yields.
1. A display device comprising a plurality of pixel cells having a common electrode switchable between a high voltage V ITO — H and a low voltage V ITO — L said display device further comprising:
a voltage controller connected to a multiplexing switch in each of said pixel cells to provide control signals to digitally select a switch-on state and a switch-off state to apply a high voltage and a low voltage on a pixel electrode in each of said pixel cells wherein said high and low voltage substantially equal to a voltage represented by V1 and V0 respectively wherein said voltage of V1 and V0 are different from voltages Vdd and Vss as as high and low rail voltages resepectively applied to a backplane of the display device;
said voltage controller further includes a DC balancing state timing controller for synchronizing an inverting operation of said substantially V1 or V0 applied to said pixel electrode and controlling an inverter in each of said pixel cells with a common electrode DC-balancing switch between said high voltage V ITO — H and low voltage V ITO — L .
2. The display device of claim 1 wherein:
said voltage controller further controlling said high voltage V ITO — H and a low voltage V ITO — L and said high voltage V1 and low voltage V0 applied to said pixel electrode different from said Vdd and Vss such that an absolute value of (V ITO — H -V0) is substantially equal to an absolute value of (V1-V ITO — L ).
3. The display device of claim 1 wherein
each of said pixel cells further comprising a data storage circuit for outputting a digital signal to said multiplexing switch to selectively apply said V1 or V0 voltages different from said Vdd and Vss to said pixel electrode and said data storage circuit further comprising a CMOS based memory device.
4. The display device of claim 3 wherein
said data storage circuit further comprising an SRAM memory device.
5. The display device of claim 4 wherein
said SRAM memory cell further comprising a 6 transistor SARM memory device.
6. The display element of claim 1 further comprising:
said inverter in each of said pixel cell further comprising an inverting level shifter connected to and receiving an output from said and controlled by said multiplexing switch for outputting a pixel voltage to said pixel electrode to reduce a pixel display transition time.
7. A display device comprising a plurality of pixel cells comprising a common electrode swichable between a high voltage V ITO — H and a low voltage V ITO — L and said display device further comprising:
a voltage controller connected to a multiplexing switch in each of said pixel cells to provide controls signals to digitally select a switch-on state and a switch-off state to apply a high voltage V1 and a low voltage V0 on a pixel electrode in each of said pixel cells and controlling an inverter in each of said pixel cells whereby a DC balancing and a pixel image transition for each of said pixel cells is achieved without requiring a contemporaneous production of an internal transition signal from within said pixel cell; and
said voltage controller further controlling said high voltage V ITO — H and said low voltage V ITO — L and said high voltage V1 and low voltage V0 applied to said pixel electrode different from voltages Vdd and Vss as high and low rail voltages respectively applied to a backplane of the display device such that absolute value of (V ITO — H -V0) is substantially equal to (V1-V ITO — L ).
8. The display device of claim 7 further comprising:
said inverter in each of said pixel cell further comprising an inverting level shifter connected to and receiving an output from and controlled by said multiplexing switch for outputting a pixel voltage to said pixel electrode to reduce a pixel display transition time.
9. A display device comprising a plurality of pixel cell comprising a common electrode switchable between a high voltage V ITO — H and a low voltage V ITO — L and said display device further comprising:
a voltage controller connected to a multiplexing switch in each of said pixel cells to provide control signals to digitally select a switch-on state and a switch-off state to apply a high voltage V1 and a low voltage V0 on a pixel electrode in each of said pixel cells and controlling an inverter in each of said pixel cells whereby a DC balancing and a pixel image transition for each of said pixel cells is achieved without requiring a contemporaneous production of an internal transition signal from within said pixel cell; and
each of said pixel cells further comprising a data storage circuit for outputting a digital signal to said multiplexing switch to selectively apply said V1 or V0 voltages to said pixel electrode and said data storage circuit further comprising a CMOS based memory device wherein said V1 and V0 voltages are different from voltages of Vdd and Vss applied to a backplane as high and low rail voltages respectively.
10. The display device of claim 7 wherein:
said multiplexing switch in each of said pixel cells further comprises a CMOS based logic device.
11. The display device of claim 7 wherein:
said multiplexing switch in each of said pixel cells further comprises a first and a second P-channel transistors.
12. The display device of claim 9 wherein:
said data storage circuit further comprising multiple CMOS transistors.
13. The display device of claim 9 wherein:
said storage element further comprising a CMOS based memory device.
14. The display device of claim 9 wherein:
said data storage circuit further a static random access memory (SRAM).
15. The display device of claim 14 wherein:
said SRAM memory cell further comprising a 6-transistor SARM memory device.
16. A method for displaying an image on a display device having a plurality of pixel cells with a common electrode switchable between a high voltage V ITO — H and a low voltage V ITO — L comprising:
connecting a voltage controller to a multiplexing switch in each of said pixel cells to provide control signals to digitally select a switch-on state and a switch-off state to apply a high voltage and a low voltage on a pixel electrode in each of said pixel cells wherein said high and low voltage substantially equal to a voltage represented by V1 and V0 respectively; and
controlling an inverter in each of said pixel cells by said controller for synchronizing an inverting of said substantially V1 or V0 applied to said pixel electrode and with a common electrode DC balancing switch between said high voltage V ITO — H and low voltage V ITO — L ; and
said step of digitally selecting a switch-on state and a switch-off state to apply a high voltage and a low voltage on a pixel electrode in each of said pixel cells further comprising a step of controlling said high common electrode voltage V ITO — H and said common electrode low voltage V ITO — L and said high voltage V1 and low voltage V0 applied to said pixel electrode such that an absolute value of (V ITO — H -V0) is substantially equal to (V1-V ITO — L ) with said V1 and V0 voltages different from voltages of Vdd and Vss applied to a backplane as high and low rail voltages respectively.
17. The method of claim 16 further comprising:
connecting a data storage circuit of a CMOS based memory to said multiplexing switch in each of said pixel cells for providing a input thereto.
18. The method of claim 16 further comprising:
connecting a data storage circuit of a SRAM memory to said multiplexing switch in each of said pixel cells for providing a input thereto.
19. The method of claim 18 wherein
said step of connecting a SRAM memory to said multiplexing switch in each of said pixel cells further comprising a step of connecting a six-transistor SRAM memory device to said multiplexing switch in each of said pixel cells.
20. The method of claim 16 wherein:
said step of controlling said inverter in each of said pixel cells further comprising a step of connecting an inverting level shifter to said multiplexing switch for receiving an input from said multiplexing switch for outputting a pixel voltage to said pixel electrode to reduce a pixel display transition time.
21. A method for displaying an image data on a display device comprising a plurality of pixel cells having a common electrode switchable between a high voltage V ITO — H and a low voltage V ITO — L and said method further comprising:
connecting a voltage controller to a multiplexing switch in each of said pixel cells to provide control signals to digitally select a switch-on state and a switch-off state to apply a high voltage V1 and a low voltage V0 on a pixel electrode in each of said pixel cells and controlling an inverter in each of said pixel cells whereby a DC balancing and a pixel image transition for each of said pixel cells is achieved without requiring a contemporaneous production of an internal transition signal from within said pixel cell; and
said step of digitally selecting a switch-on state and a switch-off state to apply a high voltage and a low voltage on a pixel electrode in each of said pixel cells further comprising a step of controlling said high common electrode voltage V ITO — H and said common electrode low voltage V ITO — L and said high voltage represented by V1 and a low voltage represented by V0 applied to said pixel electrode such that an absolute value of (V ITO — H -V0) is substantially equal to (V1-V ITO — L ) with said V1 and V0 voltages different from voltages of Vdd and Vss applied to a backplane as high and low rail voltages respectively.
22. The method of claim 21 wherein:
said step of controlling said inverter in each of said pixel cells further comprising a step of connecting an inverting level shifter to said multiplexing switch for receiving an input from said multiplexing switch for outputting a pixel voltage to said pixel electrode to reduce a pixel display transition time.
23. The method of claim 21 further comprising a step of:
storing a data bit in a data storage circuit in each of said pixel cells for inputting to said multiplexing switch for selectively applying to said pixel electrode.