Adjustable Direct-Lit Backlight Units for Display Artifacts
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Solution Overview
Problem
Direct-lit backlights in electronic devices face challenges with bulkiness and visible artifacts such as flickering and halos due to uniform brightness control, which limits dynamic range and increases power consumption.
Innovation Solution
A backlight brightness selection circuit that dynamically adjusts the brightness of light-emitting diodes based on image data, device information, and environmental conditions, using content analysis, flicker mitigation, halo mitigation, and power consumption compensation to optimize brightness levels across the display while minimizing artifacts and power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct-lit backlight units use uniform brightness control, then the display structure is simpler, but dynamic range is limited and power consumption increases
Solution Approach 1:
The backlight unit is divided into multiple independently controllable light-emitting diode regions or zones, allowing selective dimming or brightening of specific areas based on image content requirements, thereby reducing overall power consumption while maintaining necessary brightness in critical regions
Solution Approach 2:
The backlight brightness is dynamically adjusted in real-time based on image content analysis, scene characteristics, and display requirements, enabling the system to optimize power consumption by adapting brightness levels to actual viewing needs rather than maintaining uniform high brightness
2Device complexity
If direct-lit backlight units use uniform brightness control, then the control system is simpler, but dynamic range is enhanced less effectively
Solution Approach 1:
The backlight is segmented into multiple controllable zones that can be independently adjusted to create local dimming effects, enhancing contrast and dynamic range by darkening background areas while maintaining brightness in foreground regions
Solution Approach 2:
Different brightness levels are applied to different spatial regions of the backlight corresponding to different image content areas, creating local contrast enhancement and improving overall dynamic range perception in the displayed image
3Use of energy by moving object
If direct-lit backlight units dynamically adjust brightness, then power consumption is reduced, but visible artifacts such as flickering and halos occur
Solution Approach 1:
The system performs preliminary analysis of image content and anticipates brightness adjustment requirements, pre-adjusting backlight levels to prevent flickering artifacts before they occur by ensuring smooth transitions between brightness states
Solution Approach 2:
The system incorporates feedback mechanisms that monitor displayed image quality and detect artifacts such as halos or flickering, then automatically adjusts backlight brightness levels to eliminate these artifacts while maintaining power efficiency
4Illumination intensity
If locally dimmable light-emitting diodes are used, then dynamic range is enhanced, but the backlight becomes bulky
Solution Approach 1:
The backlight is divided into a limited number of controllable zones rather than individual LED control, reducing the complexity and volume of control electronics while still achieving effective local dimming to enhance dynamic range
Solution Approach 2:
Multiple light-emitting diodes are grouped into zones that are controlled collectively, reducing the number of independent control circuits needed and thereby reducing overall backlight unit volume while maintaining dynamic range enhancement capabilities
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances dynamic range, reduces visible artifacts, and optimizes power consumption by individually controlling light-emitting diodes, ensuring improved image quality and efficiency in electronic device displays.
Implementation Method 1
Direct-lit backlight units have arrays of light-emitting diodes that emit light vertically through the display
Data Source
AI summary
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.