EP2237261A1 - Repeated-scan driving method for field sequential color liquid crystal display - Google Patents
Repeated-scan driving method for field sequential color liquid crystal display Download PDFInfo
- Publication number
- EP2237261A1 EP2237261A1 EP09156874A EP09156874A EP2237261A1 EP 2237261 A1 EP2237261 A1 EP 2237261A1 EP 09156874 A EP09156874 A EP 09156874A EP 09156874 A EP09156874 A EP 09156874A EP 2237261 A1 EP2237261 A1 EP 2237261A1
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- EP
- European Patent Office
- Prior art keywords
- color
- backlights
- colors
- liquid crystal
- present
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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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
- G09G3/3622—Control of matrices with row and column drivers using a passive matrix
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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
- G09G3/3406—Control of illumination source
- G09G3/3413—Details of control of colour illumination sources
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0235—Field-sequential colour display
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0242—Compensation of deficiencies in the appearance of colours
Definitions
- the present invention relates to a REPEATED-SCAN driving method for an FSC LCD, particularly to an FSC LCD driving method, which can increase luminous flux and color saturation.
- FSC LCD Field Sequential Color Liquid Crystal Display
- multi-color backlights are sequentially switched and pass through liquid crystal optical gates.
- FSC LCD opens and closes the liquid crystal optical gates to sequentially generate pure-color fields, and then the visual persistence of human eyes mixes the pure colors to present various colors.
- the control signal 1 is used to open and close the liquid crystal optical gates.
- the light transmission curve 2 cannot instantly reflect the control signal 1 because the delayed response of liquid crystal molecules.
- Fig.2 a timing diagram of a conventional FSC LCD technology.
- the duty ratio is 1/4;
- C0, C1, and C3 (C2 is neglected) are the signals 4 scanning the common (row) electrodes of an LCD panel in a time-sharing multiplex mode;
- Sn is the signal 4 scanning the segment (column) electrodes of the LCD panel.
- the abovementioned signals 4 C0, C1, C3 and Sn cooperate with the multi-color backlights 5-a red backlight 6 (R), a green backlight 7 (G), and a blue backlight 8 (B), which sequentially and cyclically switch-to work.
- Fig.3 a diagram schematically showing the luminous fluxes of colored lights of a conventional FSC LCD driven by the signals shown in Fig.2 .
- the integral areas (the fluxes) of the red backlight 6 (R), a green backlight 7 (G), and a blue backlight 8 (B) are small and inconsistent, and the latter color may mix with the former color.
- the row luminous fluxes 9 have problems of dimness and color distortion, as shown in Fig.4 .
- the primary objective of the present invention is to provide a REPEATED-SCAN driving method for an FSC LCD to increase the luminous fluxes, bring closer the total amounts of the fluxes, and decrease flux difference between rows, whereby is achieved higher color saturation and better flux uniformity between the rows.
- Another objective is to increase the luminous fluxes with the purity of colors maintained and without color mixing occurring, whereby is improved the problem of color distortion.
- the present invention proposes a REPEATED-SCAN driving method for an FSC LCD and a device for realizing the same method.
- the method of the present invention comprises steps:
- a dark stage is arranged between the intervals respectively of two different colors of backlights and coincides with the color-mixing interval, which is caused by the response delay of liquid crystal, to prevent from mixing of different colors of backlights.
- the present invention provides a dark stage to prevent from mixing of different colors of backlights. Therefore, the present invention not only can prevent from color distortion of pure colors but also can present the correct derived colors.
- the invention also provides a device for realizing the same method such as a controller and/or driver for driving a Field Sequential Color Liquid Crystal Display.
- the present invention proposes a REPEATED-SCAN driving method for an FSC LCD 60 (Field Sequential Color Liquid Crystal Display).
- the method of the present invention provides at least two colors of backlights 20, which sequentially switch.
- a dark stage 21 is arranged between the intervals respectively of two different colors of backlights 20.
- the backlights 20 can include a red backlight 201, a green backlight 202 and a blue backlight 203, which sequentially switch.
- the dark stage 21 can be arranged in the very beginning of the backlights 20.
- the present invention provides at least one multiplex-scan signal 30.
- the sequential-color cycles 31 of the scan signals 30 are corresponding to the timing of switching the colors of backlights 20.
- Each sequential-color cycle 31 has at least two stages of scans 32.
- the duty ratio of the multiplex-scan signal 30 is exemplified by 1/4.
- C0, C1, and C3 are the signals scanning the common (row) electrodes of the LCD panel in a time-sharing mode
- Sn is the signal scanning the segment (column) electrodes of the LCD panel.
- the sequential-color cycle 31 having four stages of scans 32 is used as the exemplification.
- the multiplex-scan signal 30 in Fig.6 drives the FSC LCD 60 to output the luminous fluxes of the red backlight 201, the green backlight 202, and the blue backlight 203 shown in Fig.7 .
- Fig.7 it is known that at least two stages of scans 32 are arranged within every sequential-color cycle 31 to increase the luminous fluxes, bring closer the total amounts of fluxes, and decrease flux variation between the rows.
- the present invention can increase color saturation and promote flux uniformity between the rows.
- the method of the present invention can control the dark stage 21 to coincide with the color-mixing interval 40, which is caused by the response delay of liquid crystal.
- none color mixing occurs in the effective luminous interval 50, and color distortion is prevented. Therefore, the present invention can generate pure colors and derived colors accurately.
- the method of the present invention provides at least two stages of scans 32 for each sequential-color cycle 31 to increase row fluxes 70, bring closer the total amounts of the fluxes, and decrease flux variation between the rows, as shown in Fig.8 . Further, the method of the present invention controls the backlights 20 to form the dark stages 21 to prevent from the unwanted color mixing. Therefore, the present invention can generate the pure colors and the designed derived colors accurately.
- the present invention discloses a REPEATED-SCAN driving method, which applies to a field sequential color liquid crystal display 60, wherein each sequential-color cycle 31 of the multiplex-scan signal 30 has at least two stages of scans 32 to increase the luminous fluxes of all colors of backlights 20 and bring closer the total amounts of fluxes, whereby is achieved higher color saturation and better flux uniformity between the rows.
- the method of the present invention controls the backlights 20 to form dark stages 21 between the intervals respectively of two different colors of the backlights 20 and controls the dark stage 21 to coincide with a color-mixing interval 40, which is caused by response delay of liquid crystal, to prevent from color distortion caused by color mixing. Therefore, the present invention can generate the pure colors and the designed derived colors accurately.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Liquid Crystal (AREA)
- Liquid Crystal Display Device Control (AREA)
Abstract
Description
- The present invention relates to a REPEATED-SCAN driving method for an FSC LCD, particularly to an FSC LCD driving method, which can increase luminous flux and color saturation.
- In FSC LCD (Field Sequential Color Liquid Crystal Display), multi-color backlights are sequentially switched and pass through liquid crystal optical gates. FSC LCD opens and closes the liquid crystal optical gates to sequentially generate pure-color fields, and then the visual persistence of human eyes mixes the pure colors to present various colors. Refer to
Fig.1 . Thecontrol signal 1 is used to open and close the liquid crystal optical gates. However, thelight transmission curve 2 cannot instantly reflect thecontrol signal 1 because the delayed response of liquid crystal molecules. Thus, there areresponse delays 3 appearing in thelight transmission curve 2. - Refer to
Fig.2 a timing diagram of a conventional FSC LCD technology. In the timing diagram, the duty ratio is 1/4; C0, C1, and C3 (C2 is neglected) are thesignals 4 scanning the common (row) electrodes of an LCD panel in a time-sharing multiplex mode; Sn is thesignal 4 scanning the segment (column) electrodes of the LCD panel. Theabovementioned signals 4 C0, C1, C3 and Sn cooperate with the multi-color backlights 5-a red backlight 6 (R), a green backlight 7 (G), and a blue backlight 8 (B), which sequentially and cyclically switch-to work. - Refer to
Fig.3 a diagram schematically showing the luminous fluxes of colored lights of a conventional FSC LCD driven by the signals shown inFig.2 . InFig.3 , the integral areas (the fluxes) of the red backlight 6 (R), a green backlight 7 (G), and a blue backlight 8 (B) are small and inconsistent, and the latter color may mix with the former color. Thus, the row luminous fluxes 9 have problems of dimness and color distortion, as shown inFig.4 . - The primary objective of the present invention is to provide a REPEATED-SCAN driving method for an FSC LCD to increase the luminous fluxes, bring closer the total amounts of the fluxes, and decrease flux difference between rows, whereby is achieved higher color saturation and better flux uniformity between the rows.
- Another objective is to increase the luminous fluxes with the purity of colors maintained and without color mixing occurring, whereby is improved the problem of color distortion.
- To achieve the abovementioned objectives, the present invention proposes a REPEATED-SCAN driving method for an FSC LCD and a device for realizing the same method. The method of the present invention comprises steps:
- providing at least two colors of backlights, which sequentially switch; and
- providing at least one multiplex-scan signal with the cycle of the color sequence corresponding to the timing of switching backlight colors, wherein each cycle of the multiplex-scan signal has at least two stages of scans.
- In the present invention, a dark stage is arranged between the intervals respectively of two different colors of backlights and coincides with the color-mixing interval, which is caused by the response delay of liquid crystal, to prevent from mixing of different colors of backlights.
- In the present invention, at least two stages of scans are arranged within every sequential-color cycle to increase the luminous fluxes, bring closer the total amounts thereof, and decrease flux variation between the rows, whereby colors may have higher saturation and uniformity. Further, the present invention provides a dark stage to prevent from mixing of different colors of backlights. Therefore, the present invention not only can prevent from color distortion of pure colors but also can present the correct derived colors.
- The invention also provides a device for realizing the same method such as a controller and/or driver for driving a Field Sequential Color Liquid Crystal Display.
-
- Fig.1
- is a diagram schematically showing the imperfect optical response of a conventional FSC LCD;
- Fig.2
- is a timing diagram of a conventional multiplex-scan technology for an FSC LCD;
- Fig.3
- is a diagram schematically showing the luminous fluxes of various colors of backlights of a conventional FSC LCD;
- Fig.4
- is a diagram schematically showing color mixing and flux variation between the rows in a conventional FSC LCD;
- Fig.5
- is a diagram schematically showing an FSC LCD according to the present invention;
- Fig.6
- is a timing diagram for controlling an FSC LCD according to a method of the present invention;
- Fig.7
- is a diagram schematically showing the luminous fluxes of various colors of backlights of an FSC LCD according to the present invention; and
- Fig.8
- is a diagram schematically showing color mixing and flux variation between the rows in an FSC LCD according to the present invention.
- Below, the embodiments are described in detail in cooperation with the drawings to demonstrate the objectives, characteristics and efficacies of the present invention.
- Refer to
Fig.5 andFig.6 . The present invention proposes a REPEATED-SCAN driving method for an FSC LCD 60 (Field Sequential Color Liquid Crystal Display). The method of the present invention provides at least two colors ofbacklights 20, which sequentially switch. In the method, adark stage 21 is arranged between the intervals respectively of two different colors ofbacklights 20. Thebacklights 20 can include ared backlight 201, agreen backlight 202 and ablue backlight 203, which sequentially switch. Besides, thedark stage 21 can be arranged in the very beginning of thebacklights 20. - The present invention provides at least one multiplex-
scan signal 30. The sequential-color cycles 31 of thescan signals 30 are corresponding to the timing of switching the colors ofbacklights 20. Each sequential-color cycle 31 has at least two stages ofscans 32. In the drawings, the duty ratio of the multiplex-scan signal 30 is exemplified by 1/4. In the drawings, C0, C1, and C3 (C2 is neglected) are the signals scanning the common (row) electrodes of the LCD panel in a time-sharing mode, and Sn is the signal scanning the segment (column) electrodes of the LCD panel. In the drawings, the sequential-color cycle 31 having four stages ofscans 32 is used as the exemplification. - Refer to
Fig.7 . The multiplex-scan signal 30 inFig.6 drives theFSC LCD 60 to output the luminous fluxes of thered backlight 201, thegreen backlight 202, and theblue backlight 203 shown inFig.7 . FromFig.7 , it is known that at least two stages ofscans 32 are arranged within every sequential-color cycle 31 to increase the luminous fluxes, bring closer the total amounts of fluxes, and decrease flux variation between the rows. Thus, the present invention can increase color saturation and promote flux uniformity between the rows. Further, the method of the present invention can control thedark stage 21 to coincide with the color-mixinginterval 40, which is caused by the response delay of liquid crystal. Thus, none color mixing occurs in the effectiveluminous interval 50, and color distortion is prevented. Therefore, the present invention can generate pure colors and derived colors accurately. - In conclusion, the method of the present invention provides at least two stages of
scans 32 for each sequential-color cycle 31 to increase row fluxes 70, bring closer the total amounts of the fluxes, and decrease flux variation between the rows, as shown inFig.8 . Further, the method of the present invention controls thebacklights 20 to form thedark stages 21 to prevent from the unwanted color mixing. Therefore, the present invention can generate the pure colors and the designed derived colors accurately. - In summary the present invention discloses a REPEATED-SCAN driving method, which applies to a field sequential color
liquid crystal display 60, wherein each sequential-color cycle 31 of the multiplex-scan signal 30 has at least two stages ofscans 32 to increase the luminous fluxes of all colors ofbacklights 20 and bring closer the total amounts of fluxes, whereby is achieved higher color saturation and better flux uniformity between the rows. Further, the method of the present invention controls thebacklights 20 to formdark stages 21 between the intervals respectively of two different colors of thebacklights 20 and controls thedark stage 21 to coincide with a color-mixinginterval 40, which is caused by response delay of liquid crystal, to prevent from color distortion caused by color mixing. Therefore, the present invention can generate the pure colors and the designed derived colors accurately.
Claims (5)
- A repeated-scan driving method, which applies to a field sequential color liquid crystal display (60), characterized by steps:providing at least two colors of backlights (20), which sequentially switch;providing at least one multiplex-scan signal (30), wherein sequential-color cycles (31) of said multiplex-scan signal (30) are corresponding to timing of switching colors of said backlights (20), and wherein each of said sequential-color cycles (31) has at least two stages of scans (32).
- The repeated-scan driving method according to claim 1, wherein a dark stage (21) is arranged between intervals respectively of two different colors of said backlights (20), and said dark stage (21) is controlled to coincide with a color-mixing interval (40), which is caused by response delay of liquid crystal.
- The repeated-scan driving method according to claim 2, wherein said dark stage (21) is arranged in the very beginning of said backlight (20).
- The repeated-scan driving method according to claim 1, wherein said backlights (20) include a red backlight (201), a green backlight (202) and a blue backlight (203), which sequentially switch.
- A device for driving a field sequential color liquid crystal display (60), characterized in that:the display is providing at least two colors of backlights (20), which sequentially switch;the device is providing at least one multiplex-scan signal (30), wherein sequential-color cycles (31) of said multiplex-scan signal (30) are corresponding to timing of switching colors of said backlights (20), and wherein each of said sequential-color cycles (31) has at least two stages of scans (32).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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EP09156874A EP2237261A1 (en) | 2009-03-31 | 2009-03-31 | Repeated-scan driving method for field sequential color liquid crystal display |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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EP09156874A EP2237261A1 (en) | 2009-03-31 | 2009-03-31 | Repeated-scan driving method for field sequential color liquid crystal display |
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EP2237261A1 true EP2237261A1 (en) | 2010-10-06 |
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EP09156874A Withdrawn EP2237261A1 (en) | 2009-03-31 | 2009-03-31 | Repeated-scan driving method for field sequential color liquid crystal display |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6570554B1 (en) | 1999-11-08 | 2003-05-27 | Fujitsu Limited | Liquid crystal display |
WO2006095304A1 (en) * | 2005-03-10 | 2006-09-14 | Koninklijke Philips Electronics N.V. | Backlighted lcd display devices and driving methods therefor |
WO2006114732A1 (en) * | 2005-04-26 | 2006-11-02 | Koninklijke Philips Electronics N.V. | Liquid crystal displays with sequential drive schemes |
US20080018588A1 (en) | 2005-03-29 | 2008-01-24 | Fujitsu Limited. | Liquid crystal display device |
-
2009
- 2009-03-31 EP EP09156874A patent/EP2237261A1/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6570554B1 (en) | 1999-11-08 | 2003-05-27 | Fujitsu Limited | Liquid crystal display |
WO2006095304A1 (en) * | 2005-03-10 | 2006-09-14 | Koninklijke Philips Electronics N.V. | Backlighted lcd display devices and driving methods therefor |
US20080018588A1 (en) | 2005-03-29 | 2008-01-24 | Fujitsu Limited. | Liquid crystal display device |
WO2006114732A1 (en) * | 2005-04-26 | 2006-11-02 | Koninklijke Philips Electronics N.V. | Liquid crystal displays with sequential drive schemes |
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