Liquid crystal display device and fabricating method and driving method thereof

• US 8,624,821 B2
• Filed: 12/12/2006
• Issued: 01/07/2014
• Est. Priority Date: 06/23/2006
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kang, Hee Kwang, Choo, Kyo Seop
• Primary Examiner(s): BOYD, JONATHAN A
• Application Number:
  US11/637,096
• Publication Number:
  US 20070296685A1
• Time in Patent Office: 2,583 Days
• Field of Search: 345/99, 345/102
• US Class Current: 345/102
• CPC Class Codes: G02F 1/13312 Circuits comprising photodetectors for purposes other than feedback
• CPC Class Codes: G02F 1/13318 Circuits comprising a photodetector
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

Disclosed is a liquid crystal display device, a fabricating method, and a driving method thereof that includes at least one integrated photosensor that senses external light illumination on the liquid crystal display device. A sensing signal from the at least one photosensors are converted into a digital signal that is stored to represent an external illumination distribution. The liquid crystal display device includes a backlight that has a plurality of light sources that may be independently driven. A controller generates a control signal that independently drives the light sources in a manner corresponding to the illumination distribution. In doing so, areas of the liquid crystal display device may be provided with a greater amount of light from a corresponding light source so that externally illuminated areas of the liquid crystal display device do not suffer from reduced contrast.

Claims

1. A liquid crystal display device comprising:

a plurality of photo sensing devices formed on a TFT array substrate that sense an external light irradiated into a liquid crystal display panel, wherein the liquid crystal panel has a plurality of unit areas divided in a matrix form;

a plurality of gate lines and a plurality of data lines crossing each other to define a plurality of pixel areas;

a gate driver that sequentially provides a scan signal to the plurality of gate lines to select horizontal lines of the liquid crystal display device supplied with data signals;

a first thin film transistor connected to the n^th gate line and one of the data lines;

an integrated circuit portion that reads out sensing signals corresponding to an illumination distribution by the external light in accordance with a sensing result by each of the photo sensing devices;

a backlight having a plurality of light sources that independently supply light to the liquid crystal display panel in accordance with the illumination distribution of the plurality of unit areas; and

a backlight driver that drives the backlight,

wherein the photo sensing device includes a sensor thin film transistor that senses an external light, a first driving voltage supply line that supplies a first driving voltage to the sensor thin film transistor, a second driving voltage supply line that supplies a second driving voltage to the sensor thin film transistor and a second storage capacitor that stores a signal voltage sensed by the sensor thin film transistor,

wherein the photo sensing device further includes a second thin film transistor connected to the n−

1^th gate line and a read-out line and supplying the sensing signal to the integrated circuit portion through the read-out line,

wherein the scan signal is sequentially supplied to the second thin film transistor through the n−

1^th gate line and the first thin film transistor through the n^th gate line from the gate driver,

wherein the n−

1^th gate line and the n^th gate line are commonly connected to the gate driver,

wherein each of the light sources is arranged in the matrix form corresponding to each of the unit areas.

2. The liquid crystal display device as claimed in claim 1, further comprising:

an analog-digital converter that converts an analog signal from each of the photo sensing devices into a digital signal; and

a memory that stores an illumination distribution data corresponding to the digital signals from the analog-digital converter; and

a timing controller that generates a control signal for controlling the plurality of light sources based on the illumination distribution data and supplies the control signal to the backlight driver.

3. The liquid crystal display device as claimed in claim 1, wherein the liquid crystal display panel further includes:

a color filter array substrate joined to the TFT array substrate; and

a liquid crystal between the color filter array substrate and the TFT array substrate.

4. The liquid crystal display device as claimed in claim 1, wherein the TFT array substrate includes:

a pixel electrode connected to the first thin film transistor and positioned at the pixel area; and

a first storage capacitor that stores a pixel voltage charged into the pixel electrode.

5. The liquid crystal display device as claimed in claim 1, wherein the sensor thin film transistor includes:

a first gate electrode formed on a substrate and connected to the second driving voltage supply line;

a gate insulating film that covers the first gate electrode;

a first semiconductor pattern overlapping the first gate electrode with the gate insulating film between them;

a first source electrode electrically connected to the first semiconductor pattern and electrically connected to the first driving voltage supply line; and

a first drain electrode opposed to the first source electrode.

6. The liquid crystal display device as claimed in claim 5, further including:

a protective film that covers the sensor thin film transistor;

a first hole passing through the protective film and the gate insulating film to expose the first driving voltage supply line; and

a transparent electrode pattern formed to cover the first hole, and

wherein the first source electrode and the first driving voltage supply line are electrically connected to each other by the transparent electrode pattern.

7. The liquid crystal display device as claimed in claim 1, wherein the second thin film transistor includes:

a second gate electrode extended from the gate line;

a second semiconductor pattern overlapped with the second gate electrode with the gate insulating film between them;

a second source electrode electrically connected to the second semiconductor pattern; and

a second drain electrode connected to the sensing signal transmission line.

8. The liquid crystal display device as claimed in claim 4, wherein the first thin film transistor includes:

a third gate electrode extended from the gate line;

a third semiconductor pattern that overlaps the third gate electrode with the gate insulating film between them;

a third source electrode electrically connected to the third semiconductor pattern and extended from the data line; and

a third drain electrode connected to the pixel electrode.

9. The liquid crystal display device as claimed in claim 1, further including:

a data driver that supplies the data signals to the data line of the liquid crystal display panel.

10. A method of driving a liquid crystal display device including a plurality of gate lines and a plurality of data lines crossing each other to define a plurality of pixel areas and a first thin film transistor connected to the n^th gate line and one of the data lines, comprising:

sensing an external light irradiated onto a liquid crystal display panel using a photo sensing device provided within the liquid crystal display device, wherein the liquid crystal panel has a plurality of unit areas divided in a matrix form;

measuring an illumination distribution corresponding to the external light in accordance with a result of the sensing by the photo sensing device; and

adjusting a light amount supplied to the liquid crystal display panel in accordance with the illumination distribution of the plurality of unit areas,

wherein the photo sensing device includes a sensor thin film transistor that senses an external light, a first driving voltage supply line that supplies a first driving voltage to the sensor thin film transistor, a second driving voltage supply line that supplies a second driving voltage to the sensor thin film transistor and a second storage capacitor that stores a signal voltage sensed by the sensor thin film transistor,

wherein the photo sensing device further includes a second thin film transistor connected to the n−

1^th gate line and a read-out line and supplying a sensing signal to a read-out circuit,

wherein a scan signal is sequentially supplied to the second thin film transistor through the n−

1^th gate line and the first thin film transistor through the n^th gate line from a gate driver,

wherein the gate driver sequentially provides a scan signal to the plurality of gate lines to select horizontal lines of the liquid crystal display device supplied with data signals,

wherein the n−

1^th gate line and the n^th gate line are commonly connected to the gate driver,

wherein the light amount is emitted from each of light sources corresponding to each of the unit areas.

11. The method of driving the liquid crystal display device as claimed in claim 10, wherein adjusting the light amount in accordance with the illumination distribution includes:

converting a signal sensed by the photo sensing device into a digital signal;

providing an illumination distribution data corresponding to the digital signal; and

providing a control signal that corresponds to the illumination distribution data; and

selectively adjusting the light amount from each of the plurality of light sources according to the control signal.

12. The method of driving the liquid crystal display device as claimed in claim 11, wherein selectively adjusting the light amount includes:

supplying a first amount of light to an area where the external light is irradiated onto the liquid crystal display panel; and

supplying a second amount of light to an area other than an area where the external light is irradiated.