Mini-LED Backlight Control via Time-Multiplexed Sub-Fields
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Solution Overview
Problem
Traditional micro light-emitting diode (Mini-LED) backlights for liquid crystal display devices have high power consumption and low contrast ratios due to the need for numerous driving chips for local dimming, leading to high product costs.
Innovation Solution
A control method for a backlight unit that divides the lighting process into sub-fields with different durations, corresponding to multiple bits of data, and outputs these sub-fields in a preset order to adjust brightness and reduce power consumption, using an active control method with a charging unit, driving unit, and energy storage unit to manage light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional Mini-LED backlights use static driving scheme or passive matrix (PM) driving scheme to achieve local dimming, then local dimming function is achieved, but the number of driving chips increases significantly resulting in high product costs
Solution Approach 1:
The patent segments the backlight control into multiple partitions, with each partition controlled by a single driving chip. The driving chip divides the frame into multiple sub-fields corresponding to different bit positions, allowing each partition to be independently controlled with grayscale representation. This segmentation approach reduces the number of driving chips from one per backlight element to one per partition, significantly reducing device complexity while maintaining local dimming capability.
Solution Approach 2:
The patent introduces a time dimension by dividing the frame into multiple sub-fields with different durations. Instead of controlling each backlight element separately through multiple chips, the system uses temporal segmentation where different bit positions are represented by different sub-field durations. This dimensional transformation allows a single driving chip to control multiple partitions through time-multiplexed signaling.
2Illumination intensity
If traditional Mini-LED backlights use static driving scheme or passive matrix (PM) driving scheme, then local dimming is achieved, but power consumption remains high
Solution Approach 1:
The patent implements periodic action by dividing the frame into multiple sub-fields that are output in sequence. Each sub-field corresponds to a different bit position and has a specific duration. The driving chip periodically outputs these sub-fields in a preset order, allowing the backlight to achieve grayscale representation through temporal modulation rather than continuous high-power operation. This periodic signaling reduces overall power consumption while maintaining local dimming functionality.
Solution Approach 2:
The patent changes the parameter of sub-field duration to encode different bit positions. By varying the duration of each sub-field according to the binary weight of its corresponding bit, the system efficiently represents grayscale values with minimal signaling. This parameter change approach allows precise control of backlight intensity in each partition without requiring high power consumption, as only the necessary sub-fields are activated based on the image data.
3Area of stationary object
If the number of backlight partitions is under 2000 partitions, then local dimming coverage is sufficient, but too many driving chips are required resulting in high product costs
Solution Approach 1:
The patent makes each driving chip universal by enabling it to control multiple partitions through time-multiplexed sub-field output. A single driving chip can serve multiple partitions by sequentially outputting sub-fields for different bit positions. This multi-functionality approach allows the same driving chip design to control numerous partitions across the backlight, eliminating the need for dedicated chips for each partition and significantly reducing device complexity while maintaining sufficient partition coverage.
Solution Approach 2:
The patent uses a copying approach where the same driving chip and control logic are replicated to control multiple partitions. Instead of having unique chips for each partition, the system copies the driving chip design and uses it across multiple partitions with time-multiplexed control. This copying strategy reduces the total number of chips required while maintaining the ability to independently control each partition, thereby reducing product costs.
Data Source
AI summary
A backlight unit, a control method thereof, and a liquid crystal display device are provided. The control method includes following steps: obtaining backlight data corresponding to each of the partitions, the backlight data including multiple bits of data; dividing a frame of a lighting process of each light-emitting unit of the partitions into a plurality of sub-fields having different durations, wherein each of the sub-fields corresponds to one of the bits of data; and outputting the sub-fields having different durations corresponding to each of the partitions in a preset order.