Display Emission Duty Control for Low-Power Fine Dimming
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Solution Overview
Problem
Existing display devices face challenges in expressing a dimming level similar to a target level with minimum switching power consumption, particularly in low-resolution display panels, and there is a need for a driving method that can enhance the number of expressible dimming levels.
Innovation Solution
A display device and driving method that utilize a timing controller to determine a duty ratio bit stream with m-k most significant bits (MSBs) and k least significant bits (LSBs) fixed at a value during n frames, alternating frames with different duty ratio bit streams to achieve the desired dimming levels with reduced switching power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the duty ratio bit stream uses all m bits to control dimming levels, then the number of expressible dimming levels increases, but the switching power consumption of the dimming controller increases
Solution Approach 1:
The patent segments the m-bit duty ratio bit stream into two parts: m-k MSBs that are dynamically controlled and k LSBs that are fixed to a predetermined value. This segmentation allows the system to achieve sufficient dimming control with fewer active switching operations, reducing power consumption while maintaining acceptable dimming level precision through the combination of dynamic MSBs and fixed LSBs
Solution Approach 2:
The patent changes the parameter of bit stream configuration by fixing the k LSBs to predetermined values (0 or 1) while only varying the m-k MSBs. This parameter change reduces the number of switching operations required in the dimming controller, thereby reducing power consumption while still providing multiple dimming levels through the combination of fixed and variable bits
2Measurement precision
If the duty ratio bit stream uses all m bits for precise dimming control, then the dimming precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the bit stream into MSBs and LSBs, where only the MSBs require active control logic while the LSBs use simple fixed value assignment. This segmentation reduces controller complexity by eliminating the need for complex switching logic on all bits, while maintaining dimming precision through the combined effect of controlled MSBs and fixed LSBs
3Ease of manufacture
If the display panel has low resolution, then the manufacturing cost decreases, but the number of expressible dimming levels is limited
Solution Approach 1:
The patent adds a temporal dimension to the dimming control by utilizing frame-based alternation between different duty ratio bit streams. The system alternates between first and second duty ratio bit streams across multiple frames, effectively multiplying the number of expressible dimming levels beyond what a simple spatial resolution would allow, thereby enabling fine-grained dimming control in low-resolution panels
Data Source
AI summary
A display device may include a pixel, an emission control driver, and a timing controller. The emission control driver may supply an emission control signal set for controlling emission periods of the pixel. The timing controller may receive a received bit stream that includes a first bit set and a second bit set, may determine a first duty ratio of the emission control signal set using bits of the first bit set without using any bit of the second bit set. The first bit set may include at least two bits. The second bit set may include at least one bit. The emission control signal set may control the pixel to operate according to the first duty ratio for each frame of a first frame group.