LIQUID CRYSTAL DISPLAY APPARATUS

• US 20120169954A1
• Filed: 12/28/2011
• Published: 07/05/2012
• Est. Priority Date: 12/31/2010
• Status: Active Grant

• Current Assignee: Hung-Ta Liu
• Original Assignee: Hung-Ta Liu
• Inventors: Liu, Hung-Ta
• Granted Patent: US 8,917,228 B2
• Time in Patent Office: Days
• US Class Current: 349/38
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G09G 2300/0478 related to liquid crystal pixels
• CPC Class Codes: G09G 2300/0823 used to establish symmetry in driving, e.g. with polarity inversion
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2320/10 Special adaptations of display systems for operation with variable images
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2370/04 Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/18 Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12

Abstract

The invention discloses a liquid crystal display apparatus and a pixel element design thereof. The liquid crystal display apparatus includes a register, a liquid crystal display panel, a driving circuit, a dynamic frequency adjustment unit and a control circuit. The liquid crystal display panel includes a plurality of liquid crystal capacitors and a plurality of pixel units. The driving circuit includes a plurality of storage capacitors corresponding to the liquid crystal capacitors. A capacitance of the storage capacitors far exceeds a capacitance of the liquid crystal capacitors. The driving circuit casts the image information on the liquid crystal display panel. The dynamic frequency adjustment unit computes and judges based on an image characteristic classification of the image information, so as to generate a display mode control signal dynamically.

Claims

1. A liquid crystal display apparatus, comprising:

a register for temporarily storing image information;

a liquid crystal display panel comprising a plurality of liquid crystal capacitors, a plurality of pixel units, an upper alignment film layer and a lower alignment film layer;

a driving circuit comprising a plurality of storage capacitors corresponding to the liquid crystal capacitors, wherein a capacitance of the storage capacitors far exceeds a capacitance of the liquid crystal capacitors, and the driving circuit casts the image information on the liquid crystal display panel;

a dynamic frequency adjustment unit for computing and judging based on an image characteristic classification of the image information stored in the register and dynamically generating a display mode control signal; and

a control circuit electrically connected with the dynamic frequency adjustment unit and the driving circuit, wherein the control circuit adjusts a display refresh rate and a display configuration of the driving circuit according to the display mode control signal.

2. The liquid crystal display apparatus of claim 1, wherein the image characteristic classification comprises a dynamic image, a static slow image or a static holding image, the display configuration comprises a gray level depth.

3. The liquid crystal display apparatus of claim 2, wherein the image information further has an image characteristic sub-classification, which comprises a full color mode, an image mode, a text mode, a monochromatic image mode and/or a low gray levels mode, and the dynamic frequency adjustment unit generates a corresponding display mode control signal based on the image characteristic classification and the image characteristic sub-classification of the image information.

4. The liquid crystal display apparatus of claim 1, wherein the dynamic frequency adjustment unit at least has two or more sets of display frame rates.

5. The liquid crystal display apparatus of claim 1, wherein the driving circuit comprises two or more thin film transistor (TFT) switches, a dual-gate thin film transistor or a lightly doped drain (LDD) thin film transistor corresponding to each pixel unit, and an off-state leakage current of the driving circuit is less than or equal to 10⁻

12 ampere, the LDD TFT of the driving circuit at least has a first lightly doped drain and a second lightly doped drain with different lengths, and the first lightly doped drain nearest to the driving transistor has the largest length.

6. A liquid crystal display apparatus, comprising:

a liquid crystal display panel comprising a plurality of liquid crystal capacitors, a plurality of pixel units, an upper alignment film layer and a lower alignment film layer, wherein the liquid crystal impedance is larger than or equal to 10¹³ ohm/cm, and an alignment-film impedance of the liquid crystal display panel is larger than or equal to ten times of the liquid crystal impedance; and

a driving circuit comprising a display refresh rate and a plurality of storage capacitors, wherein the storage capacitors respectively correspond to the liquid crystal capacitors, a capacitance of the storage capacitors is larger than or equal to ten times of that of the liquid crystal capacitors, and the driving circuit casts the image information on the liquid crystal display panel, wherein the driving circuit comprises two or more thin film transistor switches, a dual-gate thin film transistor or a lightly doped drain thin film transistor corresponding to each pixel unit, and an off-state leakage current of the driving circuit is less than or equal to 10<sup>−

12</sup> ampere.

7. The liquid crystal display apparatus of claim 6, wherein an alignment-film impedance of the liquid crystal display panel is further larger than or equal to fifty times of the liquid crystal impedance, and the capacitance of the storage capacitors is larger than or equal to fifty times of that of the liquid crystal capacitors.

8. The liquid crystal display apparatus of claim 6, wherein the liquid crystal display panel comprises a plurality of pixel units, the storage capacitors respectively correspond to the pixel units, and the area ratio of the storage capacitors to the pixel units is larger than or equal to 85%.

9. The liquid crystal display apparatus of claim 6, wherein each of the plurality of pixel units of the liquid crystal display panel at least corresponds to one of the liquid crystal capacitors and one of the storage capacitors, each pixel unit comprises a first electrode layer, a second electrode layer and a third electrode layer sequentially disposed on a lower substrate, the second electrode layer comprises an extension layer of a drain layer, the third electrode layer comprises a pixel electrode layer, dielectric layer materials are respectively disposed between the first electrode layer and the second electrode layer, and between the second electrode layer and the third electrode layer, the first electrode layer comprises a gate layer and/or a common electrode conductive layer, and the extension layer of the drain layer is connected with the pixel electrode layer, and/or the common electrode conductive layer is electrically connected with a common transparent electrode layer of a upper substrate, wherein the liquid crystal capacitor is formed between the common transparent electrode layer and the pixel electrode layer of the lower substrate, and the storage capacitor is disposed between the common electrode conductive layer of the first electrode layer and the extension layer of the second electrode layer, and/or between the common electrode conductive layer of the first electrode layer and the pixel electrode layer, and/or between the gate layer of the first electrode layer and the pixel electrode layer.

10. The liquid crystal display apparatus of claim 9, wherein the pixel electrode layer is a pixel electrode layer architecture with Indium Zinc Oxide (IZO) or Indium Tin Oxide (ITO) slits, and the liquid crystal layer is constructed by negative liquid crystals aligned vertically.

11. The liquid crystal display apparatus of claim 9, wherein the pixel electrode layer, and/or the common electrode layer is a transparent electrode, a metal reflective electrode or a combination thereof, and the liquid crystal display panel is a transmissive liquid crystal display panel, a reflective liquid crystal display panel or a transflective liquid crystal display panel or a partially reflective liquid crystal display panel.

12. The liquid crystal display apparatus of claim 6, wherein each of the pixel units of the liquid crystal display panel at least corresponds to one of the liquid crystal capacitors and one of the storage capacitors, each pixel unit comprises a gate layer of a first electrode layer, a second electrode layer and a common electrode layer of a third electrode layer sequentially disposed on the lower substrate, a dielectric layer material is respectively disposed there between, the second electrode layer comprises a source layer, a drain layer and a pixel electrode layer connected with the drain layer, wherein the pixel electrode layer of the second electrode layer and the common electrode layer of the third electrode layer are of a comb-shaped or grid-shaped electrode architecture, or a curving comb-shaped or grid-shaped electrode architecture, and no common electrode layer is disposed on the upper substrate, wherein the liquid crystal capacitor is formed in the curving electric field between the pixel electrode layer of the second electrode layer and the common electrode layer of the third electrode layer, and the storage capacitor is disposed between the pixel electrode layer of the second electrode layer and the common electrode layer of the third electrode layer.

13. The liquid crystal display apparatus of claim 12, wherein the pixel electrode layer is of a fringe field switching architecture and the liquid crystal molecular layer is constructed by negative liquid crystals aligned horizontally, or the pixel electrode layer is of an in plane switching architecture and the liquid crystal molecular layer is liquid crystals aligned horizontally, and the pixel electrode layer and the common electrode layer are ITO or IZO transparent electrodes, carbon nanotube electrodes, or metal or alloy conductive electrodes.

14. The liquid crystal display apparatus of claim 12, wherein the pixel electrode layer is further a rectangle or unit-pixel electrode layer, and the common electrode layer may be a comb-shaped or grid-shaped electrode, or a curving comb-shaped or grid-shaped electrode.

15. The liquid crystal display apparatus of claim 12, wherein the pixel electrode layer, and/or the common electrode layer is a transparent electrode, a metal reflective electrode or a combination thereof, and the liquid crystal display panel is a transmissive liquid crystal display panel, a reflective liquid crystal display panel or a transflective, or partially reflective liquid crystal display panel.

16. The liquid crystal display apparatus of claim 6, wherein each of the pixel units of the liquid crystal display panel at least corresponds to one of the liquid crystal capacitors and one of the storage capacitors, each pixel unit comprises a first electrode layer and a second electrode layer sequentially disposed on the lower substrate, a dielectric layer material is respectively disposed there between, the first electrode layer comprises a gate layer and a common electrode layer, the second electrode layer comprises a source layer, a drain layer and a pixel electrode layer connected with the drain layer, the common electrode layer of the first electrode layer and the pixel electrode layer of the second electrode layer are of a comb-shaped or grid-shaped electrode architecture, or a curving comb-shaped or grid-shaped electrode architecture, and no common electrode layer is disposed on the upper substrate, wherein the liquid crystal capacitor is formed in the in plane switching field between the common electrode layer of the first electrode layer and the pixel electrode layer of the second electrode layer, and the storage capacitor is disposed between the common electrode layer of the first electrode layer and the pixel electrode layer of the second electrode layer.

17. The liquid crystal display apparatus of claim 16, wherein the pixel electrode layer is of an in plane switching architecture, the liquid crystal molecular layer is liquid crystals arranged horizontally aligned, and the pixel electrode layer and the common electrode layer are metal or alloy conductive electrodes.

18. The liquid crystal display apparatus of claim 16, wherein the storage capacitor of the pixel unit of the liquid crystal display apparatus is located at the position of the comb-shaped or grid-shaped electrode, and a comb-shaped or grid-shaped storage capacitor, or a circumambient storage capacitor is further formed.

19. The liquid crystal display apparatus of claim 16, wherein the first electrode layer and the second electrode layer which form the storage capacitor area is located at the position of the comb-shaped or grid-shaped electrode, and the width of the second electrode layer is smaller than that of the first electrode layer.

20. The liquid crystal display apparatus of claims 6, wherein the liquid crystal display apparatus at least comprises a display refresh rate less than or equal to 5 Hz, and the driving circuit of the liquid crystal display apparatus further at least comprises a row inversion driving method or a frame inversion driving method.