Curved LCD Backlight with Local Dimming for Black Mura
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Solution Overview
Problem
Curved liquid crystal displays suffer from black mura issues due to phase retardation and shear stress, leading to light leakage and reduced display quality, which existing technologies fail to adequately address.
Innovation Solution
A curved liquid crystal display system featuring a local backlight unit with controllable luminance light emitting blocks positioned behind black mura regions and a global backlight unit with uniform luminance behind non-mura regions, driven by a backlight driver to adjust luminance accordingly, thereby reducing black mura occurrences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a curved liquid crystal display is manufactured by applying external force to a flat liquid crystal display, then the display achieves constant curvature and enhanced immersion, but phase retardation of the glass substrate varies according to curvature causing black mura and light leakage
Solution Approach 1:
The backlight unit is divided into multiple independently controllable light emitting blocks corresponding to different regions of the display panel. Each block can be controlled separately to compensate for regional variations caused by curvature, specifically targeting areas prone to black mura while maintaining uniformity in other regions.
Solution Approach 2:
Different luminance levels are applied to different regions of the display. The local backlight blocks adjust their luminance independently based on the specific optical characteristics and curvature effects of each region, providing localized compensation for black mura while maintaining overall display quality.
2Ease of manufacture
If uniform backlight luminance is applied across the entire display, then manufacturing is simpler, but black mura regions cannot be compensated resulting in deteriorated display quality
Solution Approach 1:
The backlight unit is segmented into multiple independently controllable light emitting blocks. This segmentation allows different luminance levels to be applied to specific regions without requiring complete customization of the entire backlight system, balancing manufacturing simplicity with targeted black mura compensation.
Solution Approach 2:
The luminance parameter of the backlight is changed locally in different regions. By adjusting the luminance of specific light emitting blocks rather than the entire backlight, the system achieves black mura compensation while maintaining relatively simple manufacturing processes.
3Object-affected harmful factors
If local backlight units with controllable luminance are applied to black mura regions, then black mura occurrences are reduced, but device complexity increases compared to global backlight units
Solution Approach 1:
The backlight is divided into local and global units with different levels of control complexity. Local backlight blocks with controllable luminance are strategically placed only in regions prone to black mura, while other regions use simpler global backlight units, optimizing the balance between performance and complexity.
Solution Approach 2:
Enhanced control functionality is applied locally only where needed for black mura compensation rather than across the entire display. This localized approach reduces overall device complexity while still achieving the desired improvement in display quality.
4Object-affected harmful factors
If full local dimming scheme is implemented across the entire display, then black mura is completely eliminated, but manufacturing costs increase significantly
Solution Approach 1:
The display is divided into regions requiring black mura compensation and regions that do not. Local backlight blocks are implemented only in necessary regions, reducing the overall number of controllable elements and associated manufacturing costs compared to a full local dimming scheme.
Solution Approach 2:
The sophisticated local dimming functionality is applied selectively only where black mura occurs, rather than uniformly across the entire display. This targeted approach maintains manufacturing cost effectiveness while achieving the necessary display quality improvement.
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
The solution effectively minimizes black mura occurrences by locally adjusting luminance, enhancing image quality and reducing manufacturing costs compared to full local dimming schemes.
Implementation Method 1
By controlling a voltage applied to the electrodes, thereby controlling the magnitude of an electric field formed between the electrodes, the liquid crystal display is able to control the light transmittance of the liquid crystal layer to display an image
Implementation Method 2
a local backlight unit configured to irradiate beams to a first region of the liquid crystal panel and including a plurality of light emitting blocks including a first light emitting block, each of the light emitting blocks emitting beams with controllable luminance
Data Source
AI summary
A liquid crystal display includes: a liquid crystal panel including a first substrate and a second substrate facing each other, and a liquid crystal layer provided between the first substrate and the second substrate; a local backlight unit configured to irradiate beams to a first region of the liquid crystal panel and including a plurality of light emitting blocks including a first light emitting block, each of the light emitting blocks emitting beams with controllable luminance; a global backlight unit configured to irradiate beams of uniform luminance to a second region of the liquid crystal panel; and a backlight driver configured to supply a driving signal to the local backlight unit and the global backlight unit.