KR20090050229A - Liquid crystal display device and driving method thereof - Google Patents

Liquid crystal display device and driving method thereof Download PDF

Info

Publication number
KR20090050229A
KR20090050229A KR1020070116547A KR20070116547A KR20090050229A KR 20090050229 A KR20090050229 A KR 20090050229A KR 1020070116547 A KR1020070116547 A KR 1020070116547A KR 20070116547 A KR20070116547 A KR 20070116547A KR 20090050229 A KR20090050229 A KR 20090050229A
Authority
KR
South Korea
Prior art keywords
liquid crystal
crystal display
display panel
value
lines
Prior art date
Application number
KR1020070116547A
Other languages
Korean (ko)
Inventor
송현정
신대철
Original Assignee
엘지이노텍 주식회사
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 엘지이노텍 주식회사 filed Critical 엘지이노텍 주식회사
Priority to KR1020070116547A priority Critical patent/KR20090050229A/en
Publication of KR20090050229A publication Critical patent/KR20090050229A/en

Links

Images

Classifications

    • 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
    • G09G3/3648—Control of matrices with row and column drivers using an active matrix
    • G09G3/3655—Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
    • 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
    • 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
    • G09G3/3696—Generation of voltages supplied to electrode drivers
    • 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
    • G09G2310/0264—Details of driving circuits
    • G09G2310/0286—Details of a shift registers arranged for use in a driving circuit

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

The liquid crystal display according to the embodiment includes a liquid crystal display panel for displaying an image and a driving unit for driving the liquid crystal display panel, and in applying a driving signal to the liquid crystal display panel, lines provided in a front porch. The sum of the number and the number of lines included in the back porch is provided to have a value of 110 or more and a value of 300 or less.

Description

Liquid crystal display device and driving method

The embodiment relates to a liquid crystal display and a driving method thereof.

The liquid crystal display device includes a liquid crystal display panel and a driver for driving the liquid crystal display panel. In such a liquid crystal display, a voltage is applied to two electrodes to form an electric field in the liquid crystal layer, and the intensity of the electric field is adjusted to control the transmittance of light passing through the liquid crystal layer to obtain a desired image. In this case, in order to prevent deterioration caused by the application of an electric field in one direction for a long time, the polarity of the data voltage with respect to the common voltage is inverted frame by frame, row, or dot.

In the small and medium-sized liquid crystal display, line inversion is used to invert the polarity of the data voltage with respect to the common voltage Vcom in pixel rows. For example, a QVGA (Quarter Video Graphics Array) class liquid crystal display device having a resolution of 240 × 320 is applied to a mobile communication terminal. In the QVGA class liquid crystal display, the number of gate lines is 320 and the polarity of the common voltage 320 times per frame must be changed.

Accordingly, a common voltage frequency (Vcom frequency) corresponding to 11 ~ 15KHz is generated, and the generated common voltage frequency corresponds to the audible frequency region, so that the user feels sound noise.

The embodiment provides a liquid crystal display and a driving method thereof in which noise is generated by a common voltage frequency generated by inversion of an applied common voltage when applying a common voltage to a liquid crystal display panel.

The liquid crystal display according to the embodiment includes a liquid crystal display panel for displaying an image and a driving unit for driving the liquid crystal display panel, and in applying a driving signal to the liquid crystal display panel, lines provided in a front porch. The sum of the number and the number of lines included in the back porch is provided to have a value of 110 or more and a value of 300 or less.

A liquid crystal display device driving method according to an embodiment of the present invention comprises a liquid crystal display device including a liquid crystal display panel on which an image is displayed and a driving unit for driving the liquid crystal display panel, wherein the front porch is applied to the liquid crystal display panel. The sum of the number of lines provided in the front porch and the number of lines provided in the back porch is provided to have a value of 110 or more and a value of 300 or less.

According to the liquid crystal display device and the driving method thereof according to the embodiment, when applying a common voltage to the liquid crystal display panel, it is possible to prevent the noise generated by the common voltage frequency generated by the inversion of the applied common voltage. There is an advantage.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings.

1 is a diagram illustrating a liquid crystal display according to an exemplary embodiment.

As shown in FIG. 1, the liquid crystal display according to the exemplary embodiment includes a liquid crystal display panel 13 and a driver 11 driving the liquid crystal display panel 13.

In the small and medium-sized liquid crystal display, line inversion is used to invert the polarity of the data voltage with respect to the common voltage Vcom in pixel rows. For example, a QVGA (Quarter Video Graphics Array) class liquid crystal display device having a resolution of 240 × 320 is applied to a mobile communication terminal. In the QVGA class liquid crystal display, the number of gate lines is 320 and the polarity of the common voltage 320 times per frame must be changed.

Accordingly, in applying the common voltage to the liquid crystal display panel 13 in the driver 11, a common voltage frequency Vcom frequency is generated according to the inversion of the applied common voltage. The common voltage frequency generated at this time may be displayed as follows.

[Equation 1]

Common Voltage Frequency = Frame Frequency * (Lines + FP + BP) / 2

Lines: Number of lines displayed on the LCD panel

FP: Number of lines in the front porch

BP: Number of lines in the back porch

Here, the front porch and the back porch mean a delay period other than the video signal. In driving the liquid crystal display panel, a delay period from the start of the synchronization signal to the first pixel / line of the active area where an image is displayed and a delay period from the last pixel / line of the active area to the next synchronization signal is activated. Indicates.

For example, when FP is 5 and BP is 5 in a QVGA class liquid crystal display (320 Lines), the common voltage frequency generated according to the change of the frame frequency is shown in Table 1 below.

TABLE 1

No. Frame frequency (Hz) Common voltage frequency (KHz) One 70 11.5 2 80 13.2 3 90 14.8 4 100 16.5 5 110 18.1

 Increasing the frame frequency in this way also increases the common voltage frequency. Accordingly, when the frame frequency is increased to 110 Hz, the common voltage frequency can be 18.1 KHz. When the liquid crystal display device has such a common voltage frequency, the liquid crystal display device can be moved out of the audible frequency range and thus the user does not feel noise. It is reported that the user does not feel noise when the common voltage frequency is approximately 15 KHz or more.

By the way, by increasing the frame frequency it is possible to eliminate the noise generated by the common voltage frequency, but there is a disadvantage that the power consumption is increased. Therefore, the present invention is intended to suggest another method for preventing noise from being increased by the common voltage frequency while preventing power consumption from increasing.

As described in [Equation 1], the common voltage frequency is provided not only in the frame frequency but also in the number of lines (Lines) in which an image is displayed on the liquid crystal display panel, the number of lines (FP) provided in the front porch, and the back porch. The value is also changed in conjunction with the number of lines BP. For example, in the QVGA class liquid crystal display, the change of the common voltage frequency according to the change of FP value and change of BP value is shown in [Table 2].

TABLE 2

No. Frame frequency (Hz) FP (Lines) BP (Lines) Common voltage frequency (KHz) One 60 80 80 14.4 2 60 85 85 14.7 3 60 90 90 15.0 4 60 100 100 15.6 5 70 55 55 15.1 6 70 60 60 15.4 7 70 80 80 16.8 8 70 100 100 18.2

As shown in Table 2, even when the frame frequency is driven at 60 Hz or 70 Hz, when the FP value and the BP value are increased, the common voltage frequency can be greatly increased. Therefore, by adjusting the FP value and the BP value without significantly increasing the frame frequency, the required common voltage frequency of 15.0 KHz or more can be obtained.

As described above, when the frame frequency provided from the driver 11 to the liquid crystal display panel 13 is 60 Hz, the sum of the FP value and the BP value is 180 or more, so that the common voltage frequency is 15.0 KHz. The above can be implemented. In this case, the sum of the FP value and the BP value may be variously modified, and may be adjusted to be 300 or less, for example. When the sum of the FP value and the BP value is 300, the common voltage frequency is generated at 18.6 KHz.

In addition, when the frame frequency provided from the driver 11 to the liquid crystal display panel 13 is 70 Hz, the sum of the FP value and the BP value is 110 or more, so that the common voltage frequency is 15.0 KHz or more. It becomes possible. The sum of the FP value and the BP value may be variously modified, and may be adjusted to, for example, 300 or less. When the sum of the FP value and the BP value is 300, the common voltage frequency is generated at 21.7 KHz.

As an example, the number of lines included in the front porch and the number of lines provided in the back porch may be implemented to be adjusted by a register provided in the driver 11. As described above, in the driving unit 11 providing the driving signal to the liquid crystal display panel 13, by appropriately increasing the sum of the number of lines provided in the front porch and the number of lines provided in the back porch, The common voltage frequency may be outside the audible frequency band. Accordingly, noise can be prevented from being generated by the common voltage frequency, and the power consumption can be prevented from increasing because the frame frequency does not have to be increased.

1 is a view showing a liquid crystal display according to an embodiment.

<Explanation of symbols for the main parts of the drawings>

11 ... drive section

13 ... LCD panel

Claims (12)

A liquid crystal display device comprising a liquid crystal display panel displaying an image and a driving unit for driving the liquid crystal display panel. In applying the driving signal to the liquid crystal display panel, the sum of the number of lines included in the front porch and the number of lines provided in the back porch is 110 or more and is provided to have a value of 300 or less. Display. The liquid crystal display of claim 1, wherein a common voltage frequency generated in the liquid crystal display panel by a driving signal provided to the liquid crystal display panel is 15.0 KHz or more and 21.7 KHz or less. The liquid crystal display of claim 1, wherein the liquid crystal display panel has a resolution of a quarter video graphics array (QVGA). The liquid crystal display of claim 1, wherein the number of lines provided in the front porch and the number of lines provided in the back porch are adjusted by a register provided in the driving unit. The value of the line number provided in the front porch and the number of lines provided in the back porch are 180 or more and 300 or less when the frame frequency provided from the driver to the liquid crystal display panel is 60 Hz. Liquid crystal display having a. The value of the line number provided in the front porch and the number of lines provided in the back porch are 110 or more and 300 or less when the frame frequency provided from the driver to the liquid crystal display panel is 70 Hz. Liquid crystal display having a. A liquid crystal display device comprising a liquid crystal display panel displaying an image and a driving unit for driving the liquid crystal display panel. In applying the driving signal to the liquid crystal display panel, the sum of the number of lines included in the front porch and the number of lines provided in the back porch is 110 or more and is provided to have a value of 300 or less. Display device driving method. 8. The method of claim 7, wherein the common voltage frequency generated in the liquid crystal display panel by the driving signal provided to the liquid crystal display panel is adjusted to have a value of 15.0 KHz or more and 21.7 KHz or less. The method of claim 7, wherein the liquid crystal display panel has a resolution of a quarter video graphics array (QVGA). The method of claim 7, wherein the number of lines provided in the front porch and the number of lines provided in the back porch are adjusted by a register provided in the driving unit. The value of the line number provided in the front porch and the number of lines provided in the back porch are 180 or more and 300 or less when the frame frequency provided from the driver to the liquid crystal display panel is 60 Hz. A liquid crystal display driving method having a. The value of the line count provided in the front porch and the line count provided in the back porch are 110 or more and 300 or less when the frame frequency provided from the driver to the liquid crystal display panel is 70 Hz. A liquid crystal display driving method having a.
KR1020070116547A 2007-11-15 2007-11-15 Liquid crystal display device and driving method thereof KR20090050229A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020070116547A KR20090050229A (en) 2007-11-15 2007-11-15 Liquid crystal display device and driving method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020070116547A KR20090050229A (en) 2007-11-15 2007-11-15 Liquid crystal display device and driving method thereof

Publications (1)

Publication Number Publication Date
KR20090050229A true KR20090050229A (en) 2009-05-20

Family

ID=40858724

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020070116547A KR20090050229A (en) 2007-11-15 2007-11-15 Liquid crystal display device and driving method thereof

Country Status (1)

Country Link
KR (1) KR20090050229A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022231088A1 (en) * 2021-04-28 2022-11-03 엘지전자 주식회사 Display device and operation method therefor
KR20230162076A (en) 2021-04-28 2023-11-28 레온 지도키 가부시키가이샤 Kidney roller cleaning device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022231088A1 (en) * 2021-04-28 2022-11-03 엘지전자 주식회사 Display device and operation method therefor
KR20230162076A (en) 2021-04-28 2023-11-28 레온 지도키 가부시키가이샤 Kidney roller cleaning device

Similar Documents

Publication Publication Date Title
JP4997623B2 (en) Liquid crystal display device, drive control circuit used for the liquid crystal display device, and drive method
JP5414974B2 (en) Liquid crystal display
KR100841616B1 (en) Driving apparatus and its driving method of liquid crystal panel
JP4331192B2 (en) Liquid crystal display device and driving method thereof
KR101488197B1 (en) Liquid crystal display device and method of driving the same
JP2007256916A (en) Liquid crystal display device and method of driving same
KR100759697B1 (en) Liquid crystal display device and driving method thereof
JP2006084710A (en) Display control circuit, display control method, and liquid crystal display
JP2005326461A (en) Display device and driving control method of the same
TW200502909A (en) Liquid crystal display apparatus
EP2648036A1 (en) Liquid crystal display panel and drive method therefor
CN109616059B (en) Display driving device and display device
KR102148479B1 (en) Liquid Crystal Display
JP2009216997A (en) Liquid crystal display device
US7733322B2 (en) Liquid crystal display device and driving method of the same
JP5699456B2 (en) Display device
KR20040102918A (en) Apparatus of driving liquid crystal display
US20060132422A1 (en) Method of driving liquid crystal display and liquid crystal display
KR20090050229A (en) Liquid crystal display device and driving method thereof
WO2011001721A1 (en) Image display device
TW200622368A (en) Driving method of active matrix liquid crystal display panel
KR20150130220A (en) Transflective panel device
JP2010277058A (en) Image display method and image display
JP2008233416A (en) Liquid crystal display
KR100990276B1 (en) Liquid crystal display and driving method thereof

Legal Events

Date Code Title Description
WITN Withdrawal due to no request for examination