Displays with adjustable direct-lit backlight units and power consumption compensation

• US 10,571,744 B1
• Filed: 04/18/2019
• Issued: 02/25/2020
• Est. Priority Date: 04/18/2019
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chang, Sean C., Jung, Tobias, Albrecht, Marc, Hafidi, Abdeslam, Qi, Jun, Petrovich, Duane M., Gu, Mingxia, Fang, Xiang, Emelie, Pierre-Yves, Yao, Wei H
• Primary Examiner(s): Edwards, Mark
• Application Number:
  US16/388,496
• Time in Patent Office: 313 Days
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133608 including particular frames or supporting means
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3685 Details of drivers for data electrodes

Abstract

A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated by a backlight unit that includes an array of light-emitting diodes. A backlight brightness selection circuit may select brightness values for the light-emitting diodes. The backlight brightness selection circuit may select the brightness values based on image data, based on brightness values used in previous image frames, based on device information, and/or based on sensor information. The backlight brightness selection circuit may select the backlight brightness levels to mitigate visible artifacts such as flickering and halo. The backlight levels selected by the backlight brightness selection may be modified by a power consumption compensation circuit. The power consumption compensation circuit may estimate the amount of power consumption required to operate the backlight using the target brightness levels and may modify the target brightness levels to meet maximum power consumption requirements.

Claims

1. An electronic device comprising:

a plurality of pixels;

a backlight having a plurality of light-emitting diodes that are configured to produce backlight illumination for the plurality of pixels; and

control circuitry configured to;

generate brightness values for the plurality of light-emitting diodes based on image data;

determine a total power consumption associated with operating the plurality of light-emitting diodes using the brightness values, wherein the brightness values include a highest subset of brightness values; and

clip the highest subset of brightness values in response to determining that the total power consumption exceeds a maximum allowable power consumption.

2. The electronic device defined in claim 1, wherein determining the total power consumption associated with operating the plurality of light-emitting diodes using the brightness values comprises determining the total power consumption associated with operating the plurality of light-emitting diodes using the brightness values and a look-up table.

3. The electronic device defined in claim 1, wherein determining the total power consumption associated with operating the plurality of light-emitting diodes using the brightness values comprises determining a total static power consumption associated with operating the plurality of light-emitting diodes using the brightness values and wherein the control circuitry is configured to:

determine a total dynamic power consumption associated with operating the plurality of light-emitting diodes based on the brightness values and additional brightness values for at least one previous frame.

4. The electronic device defined in claim 1, wherein the control circuitry is configured to:

before clipping the highest subset of brightness values in response to determining that the total power consumption exceeds a maximum allowable power consumption, select clipping as a mitigating action from among at least two mitigation actions based at least on a display mode.

5. The electronic device defined in claim 1, wherein the control circuitry is configured to:

before clipping the highest subset of brightness values in response to determining that the total power consumption exceeds a maximum allowable power consumption, select clipping as a mitigating action from among at least two mitigation actions based at least on received electronic device information.

6. The electronic device defined in claim 5, wherein the received electronic device information comprises information regarding an application operating on the electronic device.

7. The electronic device defined in claim 1, wherein the control circuitry is configured to:

before clipping the highest subset of brightness values in response to determining that the total power consumption exceeds a maximum allowable power consumption, select clipping as a mitigating action from among at least two mitigation actions based at least on the image data.

8. An electronic device comprising:

a plurality of pixels;

a backlight having a plurality of light-emitting diodes that are configured to produce backlight illumination for the plurality of pixels;

at least one sensor configured to obtain sensor data; and

control circuitry configured to;

generate brightness values for the plurality of light-emitting diodes based on image data;

determine a total power consumption associated with operating the plurality of light-emitting diodes using the brightness values;

in response to determining that the total power consumption exceeds a maximum allowable power consumption, select, based at least on the sensor data, a mitigating action from the group consisting of;

scaling all of the brightness values and scaling only a subset of the brightness values; and

perform the mitigation action to obtain corrected brightness values.

9. The electronic device defined in claim 8, wherein the at least one sensor comprises an ambient light sensor and wherein the sensor data comprises ambient light sensor data.

10. An electronic device comprising:

a plurality of pixels;

a backlight having a plurality of light-emitting diodes that are configured to produce backlight illumination for the plurality of pixels;

a backlight brightness selection circuit configured to generate brightness values for the plurality of light-emitting diodes based on image data; and

a power consumption compensation circuit configured to modify the brightness values to meet power requirements, wherein the power consumption compensation circuit comprises a dynamic power consumption adjustment circuit that is configured to modify the brightness values to meet the power requirements based on both the brightness values for a current frame and brightness values for a previous frame.

11. The electronic device defined in claim 10, wherein the power consumption compensation circuit comprises:

a look-up table that includes a plurality of power consumption amounts associated with respective brightness values.

12. The electronic device defined in claim 11, wherein the power consumption compensation circuit comprises:

a static power consumption adjustment circuit that is configured to modify the brightness values to meet the power requirements based only on the brightness values for the current frame.

13. The electronic device defined in claim 10, further comprising:

a backlight reconstruction circuit that is configured to generate a simulated backlight reconstruction based on the modified brightness values from the power consumption compensation circuit.

14. The electronic device defined in claim 13, further comprising:

a pixel compensation circuit configured to compensate image data based on the simulated backlight reconstruction received from the backlight reconstruction circuit;

a tone mapping circuit configured to generate a plurality of tone maps based on the compensated image data received from the pixel compensation circuit; and

a pixel manipulation circuit configured to modify image data based on the plurality of tone maps received from the tone mapping circuit and configured to provide the modified image data to the plurality of pixels.