Display with peak luminance control sensitive to brightness setting

• US 9,396,684 B2
• Filed: 07/11/2014
• Issued: 07/19/2016
• Est. Priority Date: 11/06/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Bi, Yafei, Yao, Wei H.
• Primary Examiner(s): Nguyen, Kevin M
• Application Number:
  US14/329,197
• Publication Number:
  US 20150123955A1
• Time in Patent Office: 739 Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0828 forming a digital to analog [D/A] conversion circuit
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes

Abstract

A display may have an array of display pixels to display images. Digital display data may be received by a digital-to-analog converter. The digital-to-analog converter can convert the digital display data to analog display data for the display pixels. The magnitudes of the analog display data signals that the digital-to-analog converter provides to the display pixels can be controlled by a control signal such as a reference voltage received by the digital-to-analog converter. A brightness controller may have multiple peak luminance control profiles. A brightness setting may be processed by a look-up table to produce information identifying a selected one of the peak luminance control profiles. The brightness controller may use the selected peak luminance control profile and average frame luminance for the digital display data to produce the reference voltage that controls the digital-to-analog controller.

Claims

1. Display circuitry, comprising:

an array of display pixels; and

display control circuitry that displays images on the array of display pixels, wherein the display control circuitry includes;

a digital-to-analog converter that has an input that receives digital data for the images, that has an output that supplies corresponding analog data signals for the image to columns of display pixels in the array of display pixels, and that has a reference voltage input that receives a reference voltage to control the digital-to-analog converter; and

a brightness controller that receives a first input and a second input, that selects a given peak luminance control profile based on the second input, and that provides the reference voltage to the digital-to-analog converter using the selected peak luminance control profile and using the first input, wherein the brightness controller is configured to maintain a plurality of different peak luminance control profiles and is configured to select the given peak luminance control profile from among the plurality of different peak luminance control profiles based on the second input, and wherein each peak luminance control profile of the plurality of different peak luminance control profiles is a profile that maps the reference voltage as a function of the first input.

2. The display circuitry defined in claim 1 wherein the display control circuitry comprises an average luminance calculator that receives the digital data and that produces the first input, wherein the first input comprises an average frame luminance for the digital data.

3. The display circuitry defined in claim 2 wherein the display control circuitry further comprises a circuit that receives a display brightness setting and that produces corresponding information with which the brightness controller selects the given peak luminance control profile.

4. The display circuitry defined in claim 3 wherein the circuit comprises a look-up table.

5. The display circuitry defined in claim 4 wherein the look-up table has an input that receives the display brightness setting and has an output at which the information identifying the given peak luminance control profile is provided.

6. The display circuitry defined in claim 5 wherein the second input comprises the information identifying the given peak luminance control profile and wherein the brightness controller is configured to receive the information identifying the given peak luminance control profile.

7. The display circuitry defined in claim 6 wherein the information identifying the given peak luminance control profile is a peak luminance control profile number from the look-up table.

8. The display circuitry defined in claim 1 wherein the array of display pixels comprises an array of organic light-emitting diode display pixels.

9. A method of operating a display having display control circuitry that displays images on an array of display pixels, comprising:

selecting a peak luminance control profile based on a display brightness setting using the display control circuitry;

with the display control circuitry, generating a control signal using the selected peak luminance control profile;

converting digital display data to analog display data using a digital-to-analog converter that is controlled by the control signal; and

supplying the analog display data to the array of display pixels to display the images on the array of display pixels.

10. The method defined in claim 9 further comprising:

with the display control circuitry, calculating an average frame luminance for the digital display data.

11. The method defined in claim 10 wherein generating the control signal comprises generating the control signal based on the average frame luminance using the selected peak luminance control profile.

12. The method defined in claim 11 further comprising:

obtaining the display brightness setting using an ambient light sensor.

13. The method defined in claim 11 further comprising:

using an input-output device to obtain the display brightness setting from a user.

14. The method defined in claim 11 wherein the control signal comprises a reference voltage and wherein converting the digital display data comprises converting the digital display data to the analog display data based on the reference voltage.

15. A display, comprising:

a display pixel array having rows and columns of display pixels;

a digital-to-analog converter that receives digital display data and that provides corresponding analog display data signals to the columns of display pixels based on a reference voltage received at a control input to the digital-to-analog converter;

a brightness controller having a plurality of peak luminance control profiles;

a circuit that produces an output that selects one of the plurality of peak luminance control profiles that the brightness controller uses in producing the reference voltage; and

an average luminance calculator that receives the digital display data and that calculates an average luminance based on the digital display data, wherein the brightness controller is configured to use the selected one of the plurality of peak luminance control profiles to determine the reference voltage associated with the average luminance.

16. The display defined in claim 15 wherein the circuit is configured to produce the output based on a display brightness setting for the display pixel array.

17. The display defined in claim 16 wherein the circuit comprises a look-up table that receives the display brightness setting and that produces the output based on the display brightness setting.