Display Backlight Local Dimming Brightness Control
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Solution Overview
Problem
Conventional local dimming techniques for enhancing peak luminance in display apparatuses, such as liquid crystal televisions and mobile equipment, face limitations due to power constraints, particularly in small devices, where increasing peak luminance is difficult, leading to limited dynamic range and contrast ratio improvements.
Innovation Solution
A display apparatus comprising an image display panel, a planar light source with multiple light sources, and a signal processor that individually controls the brightness of each light source based on input signals to enhance the dynamic range and contrast ratio by adjusting the luminance of different areas, using an extended HSV color space to broaden the range of brightness and saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If peak luminance is enhanced in local dimming technique, then contrast ratio and dynamic range are improved, but power consumption increases and maximum luminance is limited
Solution Approach 1:
The patent divides the backlight into multiple independently controllable light sources arranged in an array, allowing selective dimming of specific regions. This segmentation enables local brightness enhancement without requiring all light sources to operate at maximum power, thus improving peak luminance in specific areas while controlling overall power consumption.
Solution Approach 2:
The patent applies different brightness levels to different regions of the display based on local image content requirements. By controlling each light source individually, the system enhances peak luminance only where needed (dark regions requiring contrast improvement) while maintaining lower brightness in other areas, optimizing the balance between luminance enhancement and power consumption.
2Illumination intensity
If local dimming is used to improve image quality, then contrast ratio increases, but the number of gradations in dark regions remains limited
Solution Approach 1:
The patent dynamically adjusts the brightness of each light source based on real-time analysis of the image content. By continuously monitoring dark regions and adapting light source intensity accordingly, the system increases the number of visible gradations in dark areas, enhancing both contrast ratio and detail visibility without being limited by static backlight configurations.
Solution Approach 2:
The patent changes the brightness parameter of individual light sources based on the luminance requirements of corresponding display regions. By precisely controlling the intensity parameter of each light source, the system expands the visible gradation range in dark regions, improving both contrast ratio and the number of distinguishable brightness levels.
Data Source
AI summary
According to an aspect, a display apparatus includes: an image display panel that displays an image thereon; a planar light source that includes a plurality of light sources and irradiates a plurality of divided areas of the image display panel with light from the back side of the image display panel; and a signal processor that drives the light sources individually based on input signals of the image to control brightness of the individual divided areas. The signal processor performs image display on the image display panel using output signals obtained by lowering brightness of a dark region in the image represented by the input signals.