Active matrix panel and method for fabricating the same

• US 5,798,742 A
• Filed: 12/16/1994
• Issued: 08/25/1998
• Est. Priority Date: 12/20/1993
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Watatani, Masahide, Shimada, Takayuki, Yamashita, Toshihiro
• Primary Examiner(s): Luu, Matthew
• Application Number:
  US08/358,012
• Time in Patent Office: 1,348 Days
• Field of Search: 345/92, 345/93, 345/94, 345/95, 345/96, 345/97, 345/98, 345/99, 345/100, 345/104, 345/206, 345/52, 359/54, 359/55, 359/56, 359/57
• US Class Current: 345/98
• CPC Class Codes: G06F 11/162 Displays
• CPC Class Codes: G09G 2300/043 Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2330/08 Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G11C 29/86 in serial access memories, e.g. shift registers, CCDs, bubble memories

Abstract

An active matrix panel includes: a liquid crystal section having a plurality of pixels arranged in a matrix; a plurality of source lines for applying video signals to the plurality of pixels; a source driver for sequentially applying the video signals to the plurality of source lines; and a plurality of sample hold capacitances for holding the video signals applied to the source line, wherein each of the source lines is connected to a predetermined number of the sample hold capacitances in parallel.

Claims

1. An active matrix panel comprising:

a liquid crystal section having a plurality of pixels arranged in a matrix;

a plurality of source lines for applying video signals to the plurality of pixels;

a source driver for sequentially applying the video signals to the plurality of source lines; and

a sample hold capacitance for holding the video signals applied to the source line,

wherein the sample hold capacitance has a pair of electrodes and at least one of the pair of electrodes is in a shape of a comb having a predetermined number of branch parts.

2. An active matrix panel according to claim 1, wherein a capacitance value of the sample hold capacitance is set so that an electric charge corresponding to one of the video signals is held by the branch parts, wherein the number of the branch parts is less than the predetermined number by one.

3. An active matrix panel according to claim 1, wherein each of the predetermined number of branch parts has a tip portion and a root portion, the root portion is connected to that of an adjacent branch part, and a width of the root portion is smaller than that of the tip portion.

9. An active matrix panel according to claim 1, wherein the source driver includes:

a plurality of sampling switching elements for, when being rendered conductive, applying the video signals to the plurality of source lines;

sampling signal applying means for sequentially applying a plurality of sampling signals to the plurality of sampling switching elements to render the plurality of sampling switching elements conductive; and

adjustment means for adjusting a timing at which each of the plurality of sampling switching elements is rendered conductive.

10. An active matrix panel according to claim 9, wherein the sampling signal applying means includes a plurality of logic elements generating the plurality of sampling signals, respectively, and the adjustment means is a plurality of load carrying capacitances, each of the plurality of load carrying capacitances being arranged in parallel with an output terminal of a corresponding logic element among the plurality of load carrying capacitances and being cut from the corresponding logic element when one of input terminals of the corresponding logic element is cut.

11. An active matrix panel according to claim 9, wherein the sampling signal applying means includes a plurality of logic elements for selectively receiving a plurality of selection signals and for generating the plurality of sampling signals in accordance with the received selection signals;

and

wherein driving abilities of the plurality of logic elements are different depending on combination of the received selection signals, and the adjusting means adjusts the driving abilities of the plurality of logic elements to be substantially equal.

12. An active matrix panel according to claim 11, wherein the plurality of logic elements have a plurality of transistors rendered conductive by the received selection signals, and the adjustment means is a plurality of load carrying capacitances, the plurality of load carrying capacitances being connected in parallel with an output terminal of a corresponding logic element in accordance with the number of transistors rendered conductive at a fall time of each of the sampling signals in the corresponding logic element.

13. An active matrix panel according to claim 11, wherein the plurality of logic elements include a plurality of transistors rendered conductive by the received selection signals, and the adjustment means includes a plurality of load carrying capacitances provided at respective output terminals of the plurality of logic elements and a changeover switching element for selectively and electrically connecting the plurality of logic elements to a corresponding load carrying capacitance in accordance with a control signal.

15. An active matrix panel according to claim 1, wherein the source driver includes:

a plurality of sampling switching elements for, when being rendered conductive, applying the video signals to the plurality of source lines; and

sampling signal applying means for sequentially applying a plurality of sampling signals which render the sampling switching elements conductive to the sampling switching elements,

wherein the sampling signal applying means includes a plurality of logic elements generating the plurality of sampling signals, respectively, each of the logic elements being provided with a plurality of transistors, and channel widths of the plurality of transistors are set in accordance with the number of transistors rendered conductive at a fall time of a corresponding sampling signal.

17. An active matrix panel according to claim 1, wherein the source driver includes:

a plurality of sampling switching elements for applying the video signals to the plurality of source lines when being rendered conductive; and

sampling signal applying means for sequentially applying a plurality of sampling signals which render the sampling switching elements conductive to the sampling switching elements,

wherein the sampling signal applying means includes a plurality of logic elements each generating the plurality of sampling signals, respectively, each of the logic elements includes a plurality of transistors, and channel lengths of the transistors are set in accordance with the number of transistors rendered conductive at a fall time of a corresponding sampling signal.

18. An active matrix panel according to claim 1, further comprising a substrate on which the liquid crystal section and the plurality of source lines are formed, wherein the source driver is formed on the substrate.

27. An active matrix panel according to claim 1, wherein the source driver includes:

a plurality of sampling switching elements for, when being rendered conductive, applying the video signals to the plurality of source lines;

a sampling signal applying circuit for sequentially applying a plurality of sampling signals to the plurality of sampling switching elements to render the plurality of sampling switching elements conductive; and

an adjustment unit for adjusting a timing at which each of the plurality of sampling switching elements is rendered conductive.

28. An active matrix panel according to claim 1, wherein the source driver includes:

a plurality of sampling switching elements for applying the video signals to the plurality of source lines when being rendered conductive; and

a sampling signal applying circuit for sequentially applying a plurality of sampling signals which render the sampling switching elements conductive to the sampling switching elements,

wherein the sampling signal applying circuit includes a plurality of logic elements each generating the plurality of sampling signals, respectively, each of the logic elements includes a plurality of transistors, and channel lengths of the transistors are set in accordance with the number of transistors rendered conductive at a fall time of a corresponding sampling signal.

4. An active matrix panel comprising:

a liquid crystal section having a plurality of pixels arranged in a matrix;

a plurality of source lines for applying video signals to the plurality of pixels;

a source driver for sequentially applying the video signals to the plurality of source lines; and

a plurality of sample hold capacitances for holding the video signals applied to the source line,

wherein each of the source lines is connected to a predetermined number of sample hold capacitances in parallel; and

wherein the source driver includes;

a plurality of sampling switching elements for, when being rendered conductive, applying the video signals to the plurality of source lines;

sampling signal applying means for sequentially applying a plurality of sampling signals to the plurality of sampling switching elements to render the plurality of sampling switching elements conductive; and

adjustment means for adjusting a timing at which each of the plurality of sampling switching elements is rendered conductive, the adjustment comprising a plurality of load carrying capacitances, each of the plurality of load carrying capacitances being arranged in parallel with an output terminal of a corresponding logic element among the plurality of load carrying capacitances and being cut from the corresponding logic element when one of input terminals of the corresponding logic element is cut.

5. An active matrix panel according to claim 4, wherein the sampling signal applying means includes a plurality of logic elements generating the plurality of sampling signals, respectively.

6. An active matrix panel according to claim 4, wherein the sampling signal applying means includes a plurality of logic elements for selectively receiving a plurality of selection signals and for generating the plurality of sampling signals in accordance with the received selection signals;

and

wherein driving abilities of the plurality of logic elements are different depending on combination of the received selection signals, and the adjusting means adjusts the driving abilities of the plurality of logic elements to be substantially equal.

7. An active matrix panel according to claim 6, wherein the plurality of logic elements have a plurality of transistors rendered conductive by the received selection signals, and the adjustment means is a plurality of load carrying capacitances, the plurality of load carrying capacitances being connected in parallel with an output terminal of a corresponding logic element in accordance with the number of transistors rendered conductive at a fall time of each of the sampling signals in the corresponding logic element.

8. An active matrix panel according to claim 6, wherein the plurality of logic elements include a plurality of transistors rendered conductive by the received selection signals, and the adjustment means includes a plurality of load carrying capacitances provided at respective output terminals of the plurality of logic elements and a changeover switching element for selectively and electrically connecting the plurality of logic elements to a corresponding load carrying capacitance in accordance with a control signal.

14. An active matrix panel comprising:

a liquid crystal section having a plurality of pixels arranged in a matrix;

a plurality of source lines for applying video signals to the plurality of pixels;

a source driver for sequentially applying the video signals to the plurality of source lines; and

a plurality of sample hold capacitances for holding the video signals applied to the source line,

wherein each of the source lines is connected to a predetermined number of sample hold capacitances in parallel; and

wherein the source driver includes;

a plurality of sampling switching elements for, when being rendered conductive, applying the video signals to the plurality of source lines; and

sampling signal applying means for sequentially applying a plurality of sampling signals which render the sampling switching elements conductive to the sampling switching elements,

wherein the sampling signal applying means includes a plurality of logic elements generating the plurality of sampling signals, respectively, each of the logic elements being provided with a plurality of transistors, and channel widths of the plurality of transistors are set in accordance with the number of transistors rendered conductive at a fall time of a corresponding sampling signal.

16. An active matrix panel comprising:

a liquid crystal section having a plurality of pixels arranged in a matrix;

a plurality of source lines for applying video signals to the plurality of pixels;

a source driver for sequentially applying the video signals to the plurality of source lines; and

a plurality of sample hold capacitances for holding the video signals applied to the source line,

wherein each of the source lines is connected to a predetermined number of sample hold capacitances in parallel; and

wherein the source driver includes;

a plurality of sampling switching elements for, when being rendered conductive, applying the video signals to the plurality of source lines when being rendered conductive; and

sampling signal applying means for sequentially applying a plurality of sampling signals which render the sampling switching elements conductive to the sampling switching elements,

wherein the sampling signal applying means includes a plurality of logic elements each generating the plurality of sampling signals, respectively, each of the logic elements includes a plurality of transistors, and channel lengths of the transistors are set in accordance with the number of transistors rendered conductive at a fall time of a corresponding sampling signal.

19. An active matrix panel comprising:

a liquid crystal section having a plurality of pixels arranged in a matrix;

a plurality of source lines for applying video signals to the plurality of pixels; and

a source driver for sequentially applying the video signals to the plurality of source lines,

the source driver including;

a plurality of sampling switching elements for, when being rendered conductive, applying the video signal to the plurality of source lines; and

sampling signal applying means for sequentially applying a plurality of sampling signals which render the sampling switching elements conductive to the sampling switching elements,

wherein the sampling signal applying means includes a plurality of logic elements for generating a plurality of sampling signals and adjustment means for adjusting a deviation of timing at which the sampling switching elements are rendered conductive, the deviation resulting from a difference in driving ability among the plurality of logic elements.

20. An active matrix panel according to claim 19, wherein the adjustment means is a plurality of load carrying capacitances, each of which is arranged in parallel with an output terminal of a corresponding logic element among the plurality of logic elements and is cut from the corresponding logic element when one of input terminal of the corresponding logic element is cut.

21. An active matrix panel according to claim 19, wherein the plurality of logic elements selectively receive a plurality of selection signals and generate the plurality of sampling signals in accordance with the received selection signals, driving abilities of the logic elements are different depending on combination of the received selection signals, and the adjustment means adjusts the driving abilities of the logic elements to be substantially equal.

22. An active matrix panel according to claim 21, wherein the plurality of logic elements include a plurality of transistors rendered conductive by the received selection signals, and the adjustment means is a plurality of load carrying capacitances, the load carrying capacitances in the corresponding logic element being connected in parallel with an output terminal of the corresponding logic element in accordance with the number of transistors rendered conductive at a fall time of each of the sampling signals.

23. An active matrix panel according to claim 21, wherein the logic elements have a plurality of transistors rendered conductive by the received selection signals, and the adjustment means has a plurality of load carrying capacitances provided at respective output terminals of the plurality of logic elements and a changeover switching element for selectively and electrically connecting the logic elements to a corresponding load carrying capacitance in accordance with a control signal.

24. An active matrix panel according to claim 19, wherein each of the plurality of logic elements has a plurality of transistors, and channel widths of the transistors are set in accordance with the number of transistors rendered conductive at a fall time of a corresponding sampling signal.

25. An active matrix panel according to claim 24, wherein each of the plurality of logic elements has a plurality of transistors, and channel lengths of the transistors are set in accordance with the number of transistors rendered conductive at a fall time of a corresponding sampling signal.

26. An active matrix panel according to claim 19, further comprising a substrate on which the liquid crystal section and the plurality of source lines are formed, wherein the source driver is formed on the substrate.