Local-Dimming Display Brightness Correction for Uniform Luminance
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Solution Overview
Problem
Existing image display devices face challenges in achieving uniform brightness in displayed images, particularly when local dimming is applied to images with uniform brightness, as the luminance of the backlight is not uniformly distributed across the plane.
Innovation Solution
The image display device employs a planar backlight with individually controllable light-emitting regions and a display panel, utilizing a controller to generate luminance and gradation setting data based on input image data and positional correction coefficients to compensate for luminance non-uniformity, ensuring uniform brightness through luminance estimation and gradation adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If local dimming is applied to improve image contrast, then the contrast of the displayed image is improved, but the brightness uniformity of the displayed image deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing luminance profile data that characterizes the light distribution characteristics of each light-emitting region before actual image display. This pre-characterization allows the controller to compensate for luminance non-uniformity in advance, enabling both local dimming for contrast improvement and brightness uniformity maintenance without real-time complex calculations
Solution Approach 2:
The patent implements feedback by using the stored luminance profile data to continuously adjust and compensate for luminance non-uniformity across different light-emitting regions. The controller references the pre-established luminance profiles to determine appropriate luminance settings for each region, creating a closed-loop system that maintains both contrast and brightness uniformity
2Reliability
If luminance setting is performed for each light-emitting region to achieve local dimming, then image contrast is improved, but the complexity of the control system increases
Solution Approach 1:
The patent reduces control system complexity by performing preliminary characterization of each light-emitting region's luminance profile and storing this data in advance. This pre-processing approach eliminates the need for complex real-time calculations during image display, as the controller can directly reference the stored luminance profile data to determine appropriate settings for each region
Solution Approach 2:
The patent uses copying by creating and storing a digital representation (luminance profile data) of each light-emitting region's light distribution characteristics. This copied data serves as a reference model that simplifies control decisions, allowing the system to replicate desired luminance patterns without complex real-time computation
Data Source
AI summary
An image display device includes a planar backlight including a plurality of light-emitting regions, a display panel including a plurality of pixels, and a controller. The controller generates luminance setting data based on image data and data of positional correction coefficients. The controller generates luminance estimation data based on the luminance setting data, luminance profile data, and the data of the positional correction coefficients. The controller generates gradation setting data based on the image data and the luminance estimation data. The controller controls the planar backlight to operate based on the luminance setting data and the display panel to operate based on the gradation setting data to display an image corresponding to the image data.