CN101271671A - Ghost wiping circuit and its method and display equipment control circuit - Google Patents
Ghost wiping circuit and its method and display equipment control circuit Download PDFInfo
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- CN101271671A CN101271671A CNA2007100882740A CN200710088274A CN101271671A CN 101271671 A CN101271671 A CN 101271671A CN A2007100882740 A CNA2007100882740 A CN A2007100882740A CN 200710088274 A CN200710088274 A CN 200710088274A CN 101271671 A CN101271671 A CN 101271671A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3674—Details of drivers for scan electrodes
- G09G3/3677—Details of drivers for scan electrodes suitable for active matrices only
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- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Liquid Crystal Display Device Control (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
An afterimage cancellation circuit of the invention comprises a detection circuit and a switch connected with the detection circuit. The detection circuit is used for detecting a first voltage signal fluctuating quickly with a voltage source and a reference voltage signal fluctuating slowly with the voltage source. When the detection circuit determines that the first voltage signal is lower than a first threshold value, the switch switches a grid of a drive transistor to the second voltage signal which is fluctuated slowly with the voltage source. When the detection circuit determines that the reference voltage signal is lower than a second threshold value, the switch switches the grid of the transistor to the low-voltage source.
Description
Technical field
The present invention relates to a kind of afterimage eliminate circuit, relate in particular to a kind of grid voltage of when shutdown, keeping to eliminate the circuit of ghost.
Background technology
General LCD on the market can afterimage when powered-down.Be conventional liquid crystal display pixel array and control circuit as shown in Figure 1, wherein gate driver circuit 11 is used for the signal of controlling and driving transistor 16.When the grid of described driving transistors 16 was high voltage, data drive circuit 12 write the holding capacitor 14 of pel array 13 with electric charge so, or electric charge is shifted out from holding capacitor 14.Because holding capacitor 14 is parallel to liquid crystal born of the same parents (1iquid cell) 15, so the charge storage of holding capacitor 14 reads and writes with regard to the view data that is synchronized with liquid crystal born of the same parents 15 with discharging.Work as voltage source V
DDDuring instantaneous trip, be responsible for the grid voltage V of the driving transistors 16 of control pel array data-signal read-write
GHAlso enter low-voltage thereupon.Because the electric charge of holding capacitor 14 can't discharge, therefore produce the problem of afterimage after voltage source cuts off.
Fig. 2 is conventional ghost generation sequential chart.Work as voltage source V
DDDuring instantaneous trip, as the position of label 21, grid voltage V
GHAlso enter low-voltage, as the position of label 22 thereupon.Because grid voltage V
GHAfter entering low-voltage the electric charge of holding capacitor 14 can't be discharged, therefore produce the problem of afterimage.
This country's patented claim discloses a kind of afterimage eliminate circuit of routine for No. 94125836 and No. 93137423, and described afterimage eliminate circuit is in voltage source V
DDForce during instantaneous trip grid voltage is maintained high level, even and if after ghost is eliminated, still maintain one short period of high level.Though therefore described conventional method can be eliminated ghost, has other noise and enter described holding capacitor in described section high level time, thereby produce other noise.
Summary of the invention
Afterimage eliminate circuit of the present invention and its method and display control circuit thereof are in order effectively to eliminate the problem of conventional display afterimage when shutting down.
Afterimage eliminate circuit of the present invention comprises testing circuit, first change-over switch and second change-over switch.Described testing circuit comprises first testing circuit and second testing circuit, and described first testing circuit is used to detect first voltage signal that changes rapidly with voltage source, and described second testing circuit is used to detect the reference voltage signal that slowly changes with voltage source.Second voltage signal that the two ends of described first change-over switch are connected respectively to grid voltage and slowly change with voltage source.The two ends of described second change-over switch are connected respectively to described grid voltage and low-voltage source.When first testing circuit judges that described first voltage signal is lower than first threshold, start first change-over switch so and close second change-over switch.When second testing circuit judges that described reference voltage signal is lower than second threshold value, start second change-over switch so and close first change-over switch.
Ghost eliminating method of the present invention comprises detection with first voltage signal of the rapid change of voltage source and the reference voltage signal that slowly changes with voltage source.When judging described first voltage signal than the low first threshold of normal working voltage, the grid with driving transistors switches to second voltage signal that slowly changes with voltage source so.When judging that described reference voltage signal is lower than second threshold value, so described grid is switched to low voltage level.
Display control circuit of the present invention can utilize afterimage eliminate circuit, holding capacitor and driving transistors to form.The output of wherein said afterimage eliminate circuit is connected to the grid of described driving transistors.
Description of drawings
Fig. 1 is conventional liquid crystal display pixel array and control circuit synoptic diagram;
Fig. 2 is the conventional sequential chart of grid voltage when shutdown;
Fig. 3 is an afterimage eliminate circuit of the present invention;
Fig. 4 is the charge pump circuit that second voltage signal of the present invention is retrieved;
Fig. 5 is the sequential chart of grid voltage of the present invention when shutdown; With
Fig. 6 (a)～6 (d) is the circuit diagram of first change-over switch of the present invention and first change-over switch.
Embodiment
Fig. 3 is an embodiment of afterimage eliminate circuit 30 of the present invention, and it comprises testing circuit 33, first change-over switch 31 and second change-over switch 32.Described testing circuit 33 comprises first testing circuit 34 and second testing circuit 35.Described first testing circuit 34 is used to detect first voltage signal that changes rapidly with voltage source, and described second testing circuit 35 is used to detect the reference voltage signal that slowly changes with voltage source.When first testing circuit 34 judges that described first voltage signal (for example is reduced to the UVLO level than normal working voltage is low to first threshold, please refer to Fig. 5) time, export control signal so starting described first change-over switch 31, and close described second change-over switch 32.The source electrode of first change-over switch 31 and drain electrode are connected respectively to second voltage signal (for example charge pump circuit) and the grid voltage V that slowly changes with voltage source
GHAfter switching to first change-over switch 31, second testing circuit 35 just continues to detect the reference voltage signal that slowly changes with voltage source.In general, in Analog Circuit Design often for cooperating various module to design reference voltage signal with its collocation, the present invention can select with voltage source slowly change reference voltage signal and used.When second testing circuit 35 judges that described reference voltage signal is lower than second threshold value (for example be reduced to 0.7 volt of level, please refer to Fig. 5), export control signal so starting second change-over switch 32, and close first change-over switch 31.The source electrode of second change-over switch 32 and drain electrode are connected respectively to low voltage level (for example ground connection) and described grid voltage V
GH
Fig. 4 is the charge pump circuit 41 that second voltage signal of the present invention is retrieved.Described charge pump circuit 41 is owing to have energy-storage travelling wave tube, and for example capacitor or comparison amplifier even if therefore voltage source cuts off, still can keep the higher voltage value.
Fig. 5 is the sequential chart of grid voltage of the present invention when shutdown, wherein V
DDThe representative voltage source, V
REFRepresent reference voltage, V
GHRepresent grid voltage.Work as V
DDDuring less than the UVLO level, grid voltage V
GHJust retrieve second voltage signal by described charge pump circuit 41 via first change-over switch 31, though wherein said second voltage signal level also slightly reduces with the cut-out of voltage source, but still can open the driving transistors 16 of liquid crystal display pixel array, and therefore the electric charge of holding capacitor 14 is released, and the present invention can solve the problem of afterimage by this.
Fig. 6 (a)～6 (d) is the embodiment of first change-over switch 31 of the present invention and second change-over switch 32.First change-over switch 31 of the present invention and second change-over switch 32 can be respectively the combination of P transistor npn npn and N transistor npn npn, P transistor npn npn and P transistor npn npn, N transistor npn npn and N transistor npn npn, P transistor npn npn and P transistor npn npn.The present invention is not limited especially to its combination.
Technology contents of the present invention and technical characterstic disclose as above, yet the those skilled in the art still may be based on teaching of the present invention and announcement and done all substitutions and modifications that do not break away from spirit of the present invention.Therefore, protection scope of the present invention should be not limited to the content that embodiment discloses, and should comprise the various substitutions and modifications of the present invention that do not break away from, and is contained by appended claims.
Claims (10)
1. afterimage eliminate circuit is characterized in that comprising:
Testing circuit, it comprises first testing circuit and second testing circuit, and described first testing circuit is used to detect first voltage signal that changes rapidly with voltage source, and described second testing circuit is used to detect the reference voltage signal that slowly changes with voltage source;
Second voltage signal that first change-over switch, its two ends are connected respectively to grid voltage and slowly change with voltage source; With
Second change-over switch, its two ends are connected respectively to described grid voltage and low-voltage source;
Wherein, when described first testing circuit judges that described first voltage signal is lower than first threshold, start described first change-over switch so and close described second change-over switch; When described second testing circuit judges that described reference voltage signal is lower than second threshold value, start described second change-over switch so and close described first change-over switch.
2. afterimage eliminate circuit according to claim 1 is characterized in that described second voltage signal retrieves from charge pump circuit.
3. afterimage eliminate circuit according to claim 1 it is characterized in that described first change-over switch is the P transistor npn npn, and described second change-over switch is the N transistor npn npn.
4. afterimage eliminate circuit according to claim 1 it is characterized in that described first change-over switch is the P transistor npn npn, and described second change-over switch is the P transistor npn npn.
5. afterimage eliminate circuit according to claim 1 it is characterized in that described first change-over switch is the N transistor npn npn, and described second change-over switch is the N transistor npn npn.
6. afterimage eliminate circuit according to claim 1 is characterized in that described first change-over switch is the P transistor npn npn, and the combination that described second change-over switch is the P transistor npn npn.
7. display control circuit is characterized in that comprising:
Holding capacitor;
Driving transistors, it has grid, and an end of wherein said driving transistors is connected to described holding capacitor;
Testing circuit, it is used to detect first voltage signal that changes rapidly with voltage source and the reference voltage signal that slowly changes with voltage source; With
Change-over switch, it is connected to described testing circuit, and wherein when described testing circuit judged that described first voltage signal is lower than first threshold, the grid with described driving transistors switched to second voltage signal that slowly changes with voltage source so; When described testing circuit judged that described reference voltage signal is lower than second threshold value, the grid with described driving transistors switched to low-voltage source so.
8. display control circuit according to claim 7 is characterized in that described second voltage signal retrieves from charge pump circuit.
9. ghost eliminating method, the driving transistors that it is used to control display is characterized in that described method comprises following steps:
Detection is with first voltage signal of the rapid change of voltage source and the reference voltage signal that slowly changes with voltage source;
When judging that described first voltage signal is lower than first threshold, the grid with described driving transistors switches to second voltage signal that slowly changes with voltage source so; With
When judging that described reference voltage signal is lower than second threshold value, so described grid is switched to low voltage level.
10. ghost eliminating method according to claim 9 is characterized in that described second voltage signal retrieves from charge pump circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007100882740A CN101271671B (en) | 2007-03-22 | 2007-03-22 | Ghost wiping circuit and its method and display equipment control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007100882740A CN101271671B (en) | 2007-03-22 | 2007-03-22 | Ghost wiping circuit and its method and display equipment control circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101271671A true CN101271671A (en) | 2008-09-24 |
| CN101271671B CN101271671B (en) | 2010-08-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007100882740A Expired - Fee Related CN101271671B (en) | 2007-03-22 | 2007-03-22 | Ghost wiping circuit and its method and display equipment control circuit |
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| CN (1) | CN101271671B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8305372B2 (en) | 2009-04-29 | 2012-11-06 | Au Optronics Corporation | Display and method for eliminating residual image thereof |
| CN101739967B (en) * | 2008-11-12 | 2012-11-07 | 瀚宇彩晶股份有限公司 | Method for eliminating shut-down afterimage of display, control panel and display thereof |
| CN102968975A (en) * | 2012-12-10 | 2013-03-13 | 京东方科技集团股份有限公司 | Liquid crystal display device and gate driving circuit voltage control method and control circuit thereof |
| US8537150B2 (en) | 2008-07-29 | 2013-09-17 | Hannstar Display Corporation | Method and control board for eliminating power-off residual images in display and display using the same |
| WO2015010360A1 (en) * | 2013-07-23 | 2015-01-29 | 合肥京东方光电科技有限公司 | Circuit, method and display for eliminating shutdown image sticking |
| CN107306129A (en) * | 2016-04-18 | 2017-10-31 | 台湾类比科技股份有限公司 | The output-stage circuit of integrated circuit |
| CN109377954A (en) * | 2018-11-14 | 2019-02-22 | 惠科股份有限公司 | Driving method and driving circuit of display panel |
| CN110310610A (en) * | 2019-07-30 | 2019-10-08 | 昆山龙腾光电有限公司 | Control circuit and its display device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1447306A (en) * | 2002-03-26 | 2003-10-08 | 华邦电子股份有限公司 | Control device and method for eliminating ghost on panels of liquid crystal |
| TWI268461B (en) * | 2004-07-30 | 2006-12-11 | Tpo Displays Corp | Image sticking prevention circuit for display device |
| CN1845233A (en) * | 2005-04-06 | 2006-10-11 | 中华映管股份有限公司 | LCD and method for improving its ghost phenomenon |
| CN100401365C (en) * | 2005-04-26 | 2008-07-09 | 乐金电子（昆山）电脑有限公司 | Residual image eliminator of liquid-crystal display device |
-
2007
- 2007-03-22 CN CN2007100882740A patent/CN101271671B/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8537150B2 (en) | 2008-07-29 | 2013-09-17 | Hannstar Display Corporation | Method and control board for eliminating power-off residual images in display and display using the same |
| CN101739967B (en) * | 2008-11-12 | 2012-11-07 | 瀚宇彩晶股份有限公司 | Method for eliminating shut-down afterimage of display, control panel and display thereof |
| US8305372B2 (en) | 2009-04-29 | 2012-11-06 | Au Optronics Corporation | Display and method for eliminating residual image thereof |
| CN102968975A (en) * | 2012-12-10 | 2013-03-13 | 京东方科技集团股份有限公司 | Liquid crystal display device and gate driving circuit voltage control method and control circuit thereof |
| CN102968975B (en) * | 2012-12-10 | 2015-06-17 | 京东方科技集团股份有限公司 | Liquid crystal display device and gate driving circuit voltage control method and control circuit thereof |
| US9865204B2 (en) | 2013-07-23 | 2018-01-09 | Boe Technology Group Co., Ltd. | Circuit and method for eliminating shutdown after-image, and display device |
| WO2015010360A1 (en) * | 2013-07-23 | 2015-01-29 | 合肥京东方光电科技有限公司 | Circuit, method and display for eliminating shutdown image sticking |
| CN107306129A (en) * | 2016-04-18 | 2017-10-31 | 台湾类比科技股份有限公司 | The output-stage circuit of integrated circuit |
| CN107306129B (en) * | 2016-04-18 | 2020-09-29 | 台湾类比科技股份有限公司 | Output stage circuit of integrated circuit |
| CN109377954A (en) * | 2018-11-14 | 2019-02-22 | 惠科股份有限公司 | Driving method and driving circuit of display panel |
| CN109377954B (en) * | 2018-11-14 | 2020-05-22 | 惠科股份有限公司 | Driving method and driving circuit of display panel |
| US11488525B2 (en) | 2018-11-14 | 2022-11-01 | HKC Corporation Limited | Display panel driving method of turning on an active switch corresponding to each pixel of the display panel for releasing charges stored in the display panel during operation, and drive circuit implementing the same |
| CN110310610A (en) * | 2019-07-30 | 2019-10-08 | 昆山龙腾光电有限公司 | Control circuit and its display device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101271671B (en) | 2010-08-25 |
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Granted publication date: 20100825 Termination date: 20170322 |