Display apparatus and display control circuit

• US 10,013,921 B2
• Filed: 02/25/2014
• Issued: 07/03/2018
• Est. Priority Date: 05/22/2013
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yamato, Asahi, Kobayashi, Fumiyuki, Kuki, Hikaru
• Primary Examiner(s): Joseph, Dennis
• Application Number:
  US14/891,901
• Publication Number:
  US 20160111047A1
• Time in Patent Office: 1,589 Days
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A display apparatus and a display control circuit which may contain an occurrence of the inappropriate brightness, such as flickering, at the time of pausing driving are provided. A scan period (St1, St2) during which a display panel drive device scans a display panel device and a retention period (Vt1) during which the display panel drive device does not scan the display panel device alternate and a timing control device causes the display panel drive device to scan the display panel device a plurality of times in the scan period when at least the brightness (Lb1) of the backlight device is changed.

Claims

1. A display apparatus, comprising:

a backlight device configured to emit a light;

a backlight drive device configured to drive the backlight device;

a display panel device configured to control a transmittance of the light emitted by the backlight device at least for each pixel;

a display panel drive device configured to scan the display panel device to cause the transmittance to be controlled;

a timing control device configured to control timing at which the display panel drive device scans the display panel device and a brightness of the backlight device, wherein

a scan period during which the display panel drive device scans the display panel device and a retention period during which the display panel drive device does not scan the display panel device alternate,

the timing control device is configured to cause the display panel drive device to scan the display panel device a plurality of times in the scan period when it changes at least the brightness of the backlight device,

the timing control device is configured to cause the display panel drive device to scan the display panel device four times during the scan period when the brightness of the backlight device is changed, and

the timing control device is configured to cause the display panel drive device to scan the display panel device one time during the scan period when the brightness of the backlight device is not changed.

2. The display apparatus as claimed in claim 1, wherein the timing control device is configured to control the backlight drive device such that the brightness of the backlight device changes gradually in the plurality of time of scans.

3. The display apparatus as claimed in claim 1, wherein the timing control device is configured to set a length of a period including the scan period and the following retention period to be constant.

4. The display apparatus as claimed in claim 1, wherein the timing control device is configured to control the display panel drive device such that polarity conversion is performed for each period including a scan period and the following retention period and is not performed for each scan during the plurality of times of scans.

5. The display apparatus as claimed in claim 1, wherein

the display panel device is configured to have a thin film transistor;

and

the thin film transistor is configured to include an oxide semiconductor.

6. The display apparatus as claimed in claim 5, wherein the oxide semiconductor is configured to include In, Ga, Zn, and O.

7. The display apparatus as claimed in claim 6, wherein the oxide semiconductor configured to include the In, Ga, Zn, and O is configured to have a crystallizing property.

8. The display apparatus as claimed in claim 1, wherein:

the timing control device includes;

an image analysis device that calculates a histogram of grey scale values of a pixel for a first frame of the scan period of an image data input to the display apparatus; and

a backlight brightness calculation device that refers to the histogram calculated by the image analysis device and calculates a target brightness of the backlight device, and

the timing control device determines, based on the target brightness calculated by the backlight brightness calculation device, whether or not to change the brightness of the backlight device.

9. The display apparatus as claimed in claim 1, wherein:

the timing control device causes the display panel drive device to scan the display panel device the plurality of times by causing the display panel drive device to cause a first scan and a second scan during the scan period,

the first scan is for a first frame of the scan period of an image data input to the display apparatus, and

the second scan is for a second frame which follows the first frame.

10. A display control circuit configured to control a backlight drive device configured to drive a backlight device which emits a light and a display panel drive device configured to scan a display panel device to cause an amount of transmittance of the light emitted by the backlight device to be controlled, the display control circuit comprising:

a timing control device configured to cause the display panel drive device to scan the display panel device a plurality of times in a scan period in which the display panel drive device scans the display panel device when at least a brightness of the backlight device is changed, wherein

the scan period and a retention period in which the display panel drive device does not scan the display panel device alternate,

the timing control device is configured to cause the display panel drive device to scan the display panel device four times during the scan period when the brightness of the backlight device is changed, and

the timing control device is configured to cause the display panel drive device to scan the display panel device one time during the scan period when the brightness of the backlight device is not changed.