Liquid Crystal Display Driving Apparatus Frame Memory Reduction
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Solution Overview
Problem
Liquid crystal display devices suffer from slow response speed, leading to motion blurring and reduced picture quality due to the need for multiple frame memories, which increase circuit costs.
Innovation Solution
A driving method and apparatus that compresses and restores frame data, compares previous and current frames to determine modulation, and modulates the current frame data to reduce the number of frame memories required, thereby improving response speed and picture quality while reducing circuit costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple frame memories are used to store previous and current frame data for comparison, then motion blurring is reduced and picture quality is improved, but circuit cost increases
Solution Approach 1:
The patent merges the functions of multiple frame memories into a single frame memory by implementing a dual-buffer structure where the same memory alternates between storing current frame data and previous frame data. This is achieved by controlling the memory to store current frame data during active display periods and previous frame data during vertical blanking periods, thereby reducing circuit cost while maintaining the capability for frame comparison to reduce motion blurring
Solution Approach 2:
The patent implements dynamic switching of the frame memory's storage function between current frame data and previous frame data based on timing signals. The memory dynamically alternates between holding current frame data for display and previous frame data for comparison, controlled by vertical synchronization signals and timing circuits, thus achieving multiple functionality with a single memory component
2Reliability
If frame data is stored and compared between previous and current frames, then motion blurring is reduced, but response speed is limited by liquid crystal properties
Solution Approach 1:
The patent performs preliminary frame comparison during the vertical blanking period before the next frame is displayed. By comparing the current frame data with the previous frame data stored in the frame memory during this idle period, the modulation decision is made in advance, allowing the liquid crystal to begin changing state earlier and thus improving response speed without compromising motion picture quality
3Speed
If data modulation is performed using look-up tables, then response speed is improved, but the number of frame memories increases
Solution Approach 1:
The patent combines the look-up table function with the single frame memory by implementing the modulation logic within the same memory structure. The frame memory not only stores frame data but also performs the comparison and modulation functions by switching between different data sets (current and previous frames) based on control signals, thereby achieving data modulation without requiring additional frame memories
Data Source
AI summary
A driving method and apparatus of a liquid crystal display device is described. Data from a current frame is compressed and delayed by a frame memory. Compressed data of the current frame and the compressed data of a previous frame from the frame memory are restored. The restored data of the previous frame is compared with the restored data of the current frame to determine a modulated portion for the current frame in accordance with the comparison result. The current frame data is modulated by adding the modulated portion to the current frame data. Only a single frame memory is disposed within the driving apparatus.