Fail-Safe Local Dimming Circuit for Display Backlight Reliability
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Solution Overview
Problem
Panel display devices with local dimming functions face issues with partial loss of display due to failures of light sources in the backlight device, which can lead to inconvenience and safety concerns, especially in applications like automotive displays.
Innovation Solution
The implementation of a display device with a backlight device and a local dimming circuit that can individually control the luminance levels of light sources based on input image data. In the event of a light source failure, the local dimming circuit enters a failure mode, controlling the luminance levels of other light sources to a predetermined level, thereby maintaining display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If local dimming function is implemented with individual light source control, then display quality and power consumption are improved, but reliability deteriorates due to partial loss of display when light sources fail
Solution Approach 1:
The backlight device is divided into multiple independently controllable light sources arranged in a two-dimensional array, allowing individual control of each light source's luminance level. This segmentation enables the fail-safe function to selectively control specific light sources based on failure detection, improving display reliability while maintaining manageable complexity through modular control.
Solution Approach 2:
The local dimming circuit includes a fail-safe function that detects light source failures and provides feedback control by adjusting the luminance levels of remaining light sources. When a light source failure is detected, the system automatically compensates by increasing the luminance of adjacent light sources, ensuring continuous reliable operation without requiring complex manual intervention.
2Use of energy by moving object
If individual light source control is used for local dimming, then dynamic contrast and power consumption are improved, but vulnerability to light source failure increases
Solution Approach 1:
The local dimming circuit is designed with a fail-safe function that anticipates potential light source failures by implementing redundant control capability. When a light source fails, adjacent light sources can compensate by increasing their luminance output, providing a cushion against total display failure and maintaining reliability without requiring additional physical light sources.
Solution Approach 2:
The system dynamically changes the luminance parameter of light sources based on operational conditions. When failure is detected, the luminance level of adjacent light sources is increased to compensate for the failed source. This parameter adjustment allows the system to maintain display reliability while continuing to optimize power consumption through selective control.
3Reliability
If adjacent light sources compensate for failed ones, then display continuity is maintained, but luminance uniformity deteriorates
Solution Approach 1:
The fail-safe function implements local quality control by adjusting the luminance levels of specific adjacent light sources based on which light source has failed. Rather than uniformly increasing all light sources, the system selectively compensates only in the affected local area, maintaining overall luminance uniformity while ensuring display continuity in the specific region where failure occurred.
Data Source
AI summary
A display device that includes a backlight device and a local dimming circuit. The backlight device includes a plurality of light sources configured to illuminate a display panel. The local dimming circuit is configured to individually control luminance levels of the plurality of light sources based on first input image data in a first local dimming mode. The local dimming circuit is further configured to enter a failure mode in response to a failure of at least one of the plurality of light sources and control luminance levels of others of the plurality of light sources to a predetermined luminance level in the failure mode.