Display Device Subframe Tonal Data Division for Moving Image Clarity
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Solution Overview
Problem
Hold type display devices, such as TFT liquid crystal displays, suffer from moving image blur due to the pseudo impulse type driving methods that lower luminance and contrast, and existing solutions require large capacity look-up tables (LUTs) that increase cost and circuit area, making them unsuitable for mobile devices.
Innovation Solution
The method involves dividing digital tonal data into dark and bright subframes, calculating subframe tonal data using digital signal processing, and storing only necessary parameters in a register, eliminating the need for a large LUT and reducing costs while improving moving image display performance without lowering luminance and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pseudo impulse type driving method is used to improve moving image clarity, then moving image blur is reduced, but luminance and contrast are lowered
Solution Approach 1:
The patent divides one frame into multiple subframes with different luminance levels (dark subframe and bright subframe). The dark subframe reduces afterimage effects to improve moving image clarity, while the bright subframe compensates for luminance loss. This segmentation of temporal display into multiple subframes with varying luminance characteristics resolves the contradiction between improving moving image clarity and maintaining overall luminance and contrast.
2Manufacturing precision
If LUT is used for subframe data conversion, then pseudo impulse type driving can be realized, but circuit area and cost increase
Solution Approach 1:
The patent replaces the traditional LUT (Look-Up Table) hardware structure with a computational algorithm implemented in software or firmware. Instead of using a large capacity storage device to store pre-computed subframe data, the invention calculates subframe data in real-time using pixel data processing operations. This substitution of hardware storage with computational processing dramatically reduces circuit area while maintaining the ability to generate the required subframe data for pseudo impulse type driving.
3Adaptability or versatility
If large capacity LUT is mounted on hardware, then data conversion for pseudo impulse driving is enabled, but cost increases
Solution Approach 1:
The patent replaces expensive hardware LUT storage with a computational algorithm that processes pixel data to generate subframe data. The invention uses arithmetic operations on pixel values to create the dark and bright subframes without requiring large capacity memory storage. This approach enables pseudo impulse driving capability while significantly reducing manufacturing cost by eliminating the need for expensive large-capacity LUT hardware.
Data Source
AI summary
Tonal data of one frame of a video signal is subject to time division into dark subframe tonal data at a low tone and bright subframe tonal data at a high tone to compensate for a lowered luminance in the dark subframe by the bright subframe so as not to change an integrated luminance per one ordinary frame. Subframe tonal data read from a memory is converted into output tonal data constituted of dark subframe tonal data at a low tone and bright subframe tonal data at a high tone, by four arithmetic calculation operations using calculation parameters supplied from a register.