Apparatus for driving display apparatus

• US 6,002,384 A
• Filed: 06/27/1996
• Issued: 12/14/1999
• Est. Priority Date: 08/02/1995
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ogawa, Yoshinori, Tamai, Shigeki
• Primary Examiner(s): Lao, Lun-Yi
• Application Number:
  US08/671,514
• Time in Patent Office: 1,265 Days
• Field of Search: 345/87, 345/89, 345/94, 345/95, 345/96, 345/204, 345/205, 345/208, 345/209, 345/210, 345/63, 345/211, 345/148, 345/92, 345/147, 345/88
• US Class Current: 345/95
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

Input connection terminals of a source driver of an active matrix type liquid crystal display panel, and analog switches are reduced in number. Two of four reference voltages V0, V2, V5 and V7 are combined with each other to output, in total, three combinations (V0, V2), (V2, V5) and (V5, V7) to two reference voltage lines and in each one of three first time periods W1a, W1b and W1c. Analog switches ASW0 and ASW2 for generating voltage are interposed in the respective reference voltage lines. The analog switches are turned on and off under control based on 3-bit display data D0, D1 and D2 for 8-level gradation in second time periods W2 and W3, which are shorter than the first time period W1, within any one of the first time periods W1, whereby a vibrating voltage is supplied to the source lines. Positively utilizing a low pass filter function of the source line due to the capacity and the resistance of the source line, voltages are averaged.

Claims

1. An apparatus for driving a display apparatus, which outputs one reference voltage continuously or at least two reference voltages in a time sharing manner, to the display apparatus, the one or at least two reference voltages being selected from among plural direct current reference voltages generated by a reference voltage source in accordance with display data, the apparatus for driving a display apparatus comprising:

a plurality of input terminals;

multiple value voltage generation means, coupled to the reference voltage source, for selecting and supplying different ones of the plural direct current reference voltages to said plurality of input terminals in a time sharing manner;

output terminals coupled to the display apparatus;

a plurality of switching elements respectively interposed between each of said plurality of input terminals and each of said output terminals, said switching elements being turned on and off in response to a control signal; and

control means for outputting the control signal for providing on-off control of said switching elements in accordance with the display data, said control means outputting the control signal with a predetermined timing corresponding to the display data,

each of said switching elements comprising plural switches, a number of the plural switches in a switching element being less than a number of the plural direct current reference voltages generated by the reference voltage source.

2. The apparatus for driving a display apparatus of claim 1, wherein pairs of said plurality of input terminals are provided corresponding to each of said output terminals,

a respective different one of said plural switches being provided for each of said plurality of input terminals as interposed between a respective one of said plurality of input terminals and a corresponding one of said output terminals,

said multiple value voltage generation means supplying the plural direct current reference voltages to said plurality of input terminals corresponding to respective ones of said output terminals in sequence of from high to low or from low to high voltage with lapse of time in a time sharing manner in each repeated cycle plural times, and

the plural direct current reference voltages supplied at one time to the respective input terminals of the respective pairs of said plurality of input terminals being shifted by one reference voltage with respect to each other.

3. The apparatus for driving a display apparatus of claim 1, wherein at least two respective different pairs of input terminals are provided corresponding to each of said output terminals,

a respective different one of said plural switches being provided for each of said plurality of input terminals as interposed between a respective one of said plurality of input terminals and a corresponding one of said output terminals,

the plural direct current reference voltages supplied by said multiple value voltage generation means being divided into plural groups for each pair of said plurality of input terminals,

said multiple value voltage generation means supplying the plural direct current reference voltages to the respective pairs of said plurality of input terminals plural times in sequence of from high to low or from low to high voltage with lapse of time in a time sharing manner in each repeated cycle, and

the plural direct current reference voltages supplied at one time to the respective input terminals of the respective pairs of said plurality of input terminals being shifted by one reference voltage with respect to each other.

4. The apparatus for driving a display apparatus of claim 1, wherein a first plurality of different respective input terminals are provided as corresponding to each of said output terminals,

a respective different one of said plural switches being provided for each of said plurality of input terminals as interposed between a respective one of said plurality of input terminals and a corresponding one of said output terminals,

said multiple value voltage generation means supplying a second plurality of the plural direct current reference voltages, which is larger in number than the first plurality of different respective input terminals, to said plurality of input terminals in sequence of from high to low or from low to high voltage with lapse of time in a time sharing manner in each repeated cycle plural times, and

the plural direct current reference voltages supplied at one time to the respective input terminals of each first plurality of different respective input terminals, excluding a first supply period in each cycle, containing only one of the plural direct current reference voltages supplied in a preceding supply period.

5. The apparatus for driving a display apparatus of claim 1, wherein said switching elements and said control means are a first integrated circuit, and said multiple value voltage generation means is a second integrated circuit.

6. The apparatus for driving a display apparatus of claim 5 wherein a plurality of first integrated circuits are provided and said second integrated circuit is common to all of said plurality of first integrated circuits.

7. The apparatus for driving a display apparatus of claim 1, wherein said switching elements and said multiple value voltage generation means are one integrated circuit.

8. The apparatus for driving a display apparatus of claim 1, wherein a slit period synchronized with a predetermined cycle of the plural direct current reference voltages output from said multiple value voltage generation means is provided.

10. The apparatus for driving a display apparatus of any one of claims 1 or 9 wherein said multiple value voltage generation means comprises an analog switch which is interposed between a line from which the plural direct current reference voltages are derived from the reference voltage source and each of said plurality of input terminals, and is turned on and off by a reference voltage control signal,

the reference voltage control signal being periodically generated and supplied to said analog switch.

11. The apparatus for driving a display apparatus of claim 1 or 9 further comprising reference voltage selection control means for generating reference voltage control signals in accordance with a duty pulse,

said multiple value voltage generation means selecting and supplying different ones of the plural direct current reference voltages to said plurality of input terminals in a time sharing manner in accordance with the reference voltage control signals.

12. The apparatus for driving a display apparatus of claim 1 or 9 further comprising reference voltage selection control means for generating reference voltage control signals in accordance with a duty pulse,

said control means generating the control signal in accordance with the reference voltage control signals, the display data and the duty pulse.

9. An apparatus for driving a display apparatus, which outputs one reference voltage continuously or at least two reference voltages in a time sharing manner, to the display apparatus, the one or at least two reference voltages being selected from among plural direct current reference voltages generated by a reference voltage source in accordance with display data, the apparatus for driving a display apparatus comprising:

a plurality of input terminals;

multiple value voltage generation means, coupled to the reference voltage source, for selecting and supplying different ones of the plural direct current reference voltages to said plurality of input terminals in a time sharing manner,

slit periods wherein the plural direct current reference voltages are not supplied being inserted at intervals from ends of periods when respective ones of the plural direct current reference voltages are supplied to beginnings of respective following ones of the plural direct current reference voltages, upon changeover of the plural direct current reference voltages;

output terminals coupled to the display apparatus;

a switching element, interposed between each of said input terminals and each of said output terminals, said switching element being turned on and off in response to a control signal; and

control means for outputting the control signal for providing on-off control of said switching element in accordance with the display data, said control means outputting the control signal with a predetermined timing corresponding to the display data.

13. The apparatus for driving a display apparatus of claim 9 wherein pairs of said plurality of input terminals are provided corresponding to each of said output terminals,

said switching element comprising plural switches, a respective different one of said plural switches being provided for each of said plurality of input terminals as interposed between a respective one of said plurality of input terminals and a corresponding one of said output terminals,

said multiple value voltage generation means supplying the plural direct current reference voltages to said plurality of input terminals corresponding to respective ones of said output terminals in sequence of from high to low or from low to high voltage with lapse of time in a time sharing manner in each repeated cycle plural times, and

the plural direct current reference voltages supplied at one time to the respective input terminals of the respective pairs of said plurality of input terminals being shifted by one reference voltage with respect to each other.

14. The apparatus for driving a display apparatus of claim 9 wherein at least two respective different pairs of input terminals are provided corresponding to each of said output terminals,

said switching element comprising plural switches, a respective different one of said plural switches being provided for each of said plurality of input terminals as interposed between a respective one of said plurality of input terminals and a corresponding one of said output terminals,

the plural direct current reference voltages supplied by said multiple value voltage generation means being divided into plural groups for each pair of said plurality of input terminals,

said multiple value voltage generation means supplying the plural direct current reference voltages to the respective pairs of said plurality of input terminals plural times in sequence of from high to low or from low to high voltage with lapse of time in a time sharing manner in each repeated cycle, and

the plural direct current reference voltages supplied at one time to the respective input terminals of the respective pairs of said plurality of input terminals being shifted by one reference voltage with respect to each other.

15. The apparatus for driving a display apparatus of claim 9 wherein a first plurality of different respective input terminals are provided as corresponding to each of said output terminals,

said switching element comprising plural switches, a respective different one of said plural switches being provided for each of said plurality of input terminals as interposed between a respective one of said plurality of input terminals and a corresponding one of said output terminals,

said multiple value voltage generation means supplying a second plurality of the plural direct current reference voltages, which is larger in number than the first plurality of different respective input terminals, to said plurality of input terminals in sequence of from high to low or from low to high voltage with lapse of time in a time sharing manner in each repeated cycle plural times, and

the plural direct current reference voltages supplied at one time to the respective input terminals of each first plurality of different respective input terminals, excluding a first supply period in each cycle, containing only one of the plural direct current reference voltages supplied in a preceding supply period.

16. The apparatus for driving a display apparatus of claim 9, wherein said switching element and said control means are a first integrated circuit, and said multiple value voltage generation means is a second integrated circuit.

17. The apparatus for driving a display apparatus of claim 9, wherein said switching element and said multiple value voltage generation means are one integrated circuit.

18. An apparatus for driving a display comprising:

a reference voltage source for generating reference voltages;

a voltage selector, coupled to said reference voltage source, for selecting and outputting different ones of the reference voltages; and

a source driver for providing driving signals to a display in accordance with outputs of said voltage selector,

wherein said voltage selector is for selecting and outputting a first plurality of the reference voltages in sequence to a first input terminal of said source driver, and for selecting and outputting a second plurality of the reference voltages in sequence to a second input terminal of said source driver, and wherein voltages are simultaneously applied to said first and second input terminals.

19. The apparatus for driving a display of claim 18, wherein said reference voltage source generates first through fourth reference voltages, said voltage selector selecting and outputting the first and third reference voltages in sequence to the first input terminal of said source driver and the second and fourth reference voltages to the second input terminal of said source driver.

20. The apparatus for driving a display of claim 19, wherein the second reference voltage is greater than the first reference voltage, the third reference voltage is greater than the second reference voltage and the fourth reference voltage is greater than the third reference voltage.

21. The apparatus for driving a display of claim 19, wherein said voltage selector outputs the sequence of the first and third reference voltages to the first terminal of said source driver repeatedly and outputs the sequence of the second and fourth reference voltages to the second terminal of said source driver repeatedly.

22. The apparatus for driving a display apparatus of claim 19, wherein said voltage selector synchronizes output of the first through fourth reference voltages to said source driver such that the first and second reference voltages, the second and third reference voltages and the third and fourth reference voltages are simultaneously provided as respective pairs to the first and second terminals of said source driver.

23. The apparatus for driving a display of claim 18, wherein said voltage selector selects and outputs different ones of the plurality of reference voltages in accordance with a duty pulse and a latch signal.

24. The apparatus according to claim 18, wherein the first plurality of reference voltages is a first set of a plurality of distinct reference voltages, and the second plurality of reference voltages is a second set of a plurality of distinct reference voltages.

25. A method of driving a display comprising the steps of:

a) generating reference voltages;

b) selecting and providing different ones of the reference voltages to a source driver; and

c) providing driving signals from the source driver to a display in accordance with selected reference voltages of step b),

said step b) comprising selecting and providing a first plurality of the reference voltages in sequence to a first input terminal of said source driver, and selecting and providing a second plurality of the reference voltages in sequence to a second input terminal of the source driver, wherein voltages are simultaneously applied to said first and second input terminals.

26. The method of driving a display of claim 25 wherein said step a) comprises generating first through fourth reference voltages, said step b) comprising selecting and providing the first and third reference voltages in sequence to the first input terminal of the source driver and the second and fourth reference voltages to the second input terminal of the source driver.

27. The method of driving a display of claim 26, wherein the second reference voltage is greater than the first reference voltage, the third reference voltage is greater than the second reference voltage and the fourth reference voltage is greater than the third reference voltage.

28. The method of driving a display of claim 26 wherein said step b) comprises providing the sequence of the first and third reference voltages to the first terminal of the source driver repeatedly and providing the sequence of the second and fourth reference voltages to the second terminal of the source driver repeatedly.

29. The method of driving a display apparatus of claim 26 wherein said step b) comprises synchronizing provision of the first through fourth reference voltages to the source driver such that the first and second reference voltages, the second and third reference voltages and the third and fourth reference voltages are simultaneously provided as respective pairs to the first and second terminals of the source driver.

30. The method of driving a display of claim 25, wherein said step b) comprises selecting and outputting different ones of the plurality of reference voltages in accordance with a duty pulse and a latch signal.

31. The method according to claim 25, wherein step b) further comprises selecting and outputting a first set of a plurality of distinct reference voltages in sequence to a first input terminal of a source driver, and selecting and outputting a second set of a plurality of distinct reference voltages in sequence to a second input terminal of the source driver.