Display Control Circuit for Liquid Crystal After-Image Noise Suppression
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Solution Overview
Problem
Liquid crystal display devices face degradation in display quality due to slow response times, leading to after-image noise from incorrect gray scale level predictions during compression and decoding, especially when using high-compression-ratio BTC methods.
Innovation Solution
A display control circuit that predicts and selects between input and achievable gray scale level data based on differential values, compressing data irreversibly to prevent after-image noise by using a Block Truncation Coding method with a variable length code, ensuring accurate decoding and reduced noise perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If high-compression-ratio BTC method is used to compress image data, then data compression ratio is improved, but after-image noise is generated due to decoding errors
Solution Approach 1:
The patent applies preliminary anti-action by predicting potential decoding errors before they occur. The error noise predicting part calculates predicted values based on input image data and determines whether abnormal noise will be generated during decompression. When abnormal noise is predicted, the system switches to using input image data instead of compressed data, thereby preventing the noise from appearing in the final display.
Solution Approach 2:
The patent introduces an intermediary mechanism (error noise predicting part and data selecting part) between the compression decoding process and the final image display. This intermediary predicts decoding errors, selects appropriate data sources (compressed or uncompressed), and switches data sources based on prediction results, thereby mediating between compression efficiency and image quality.
2Ease of manufacture
If liquid crystal display device uses slow response liquid crystal particles, then manufacturing cost is reduced, but display quality degrades due to gray scale level change delays
Solution Approach 1:
The patent applies preliminary action by performing error prediction and data selection before the actual image display. The system predicts potential decoding errors in advance, selects the appropriate data source (compressed or uncompressed) based on the prediction, and only then proceeds with the display process. This preliminary action prevents quality degradation without requiring faster liquid crystal response.
Data Source
AI summary
In a display control circuit of this invention, a write gray scale level determining part outputs write gray scale level data for performing overshoot drive on a liquid crystal display device. Moreover, an achievable gray scale level determining part outputs achievable gray scale level data indicating a gray scale level which achieves after a lapse of one frame. Further, an error noise predicting part compares, with a predetermined threshold value, predicted values as differences between gray scale level values of plural pieces of input image data and a mean gray scale level value of these gray scale level values to control a data selecting part such that when at least one of the predicted values exceeds the threshold value, the data selecting part gives, to an image compressing part, the input image data rather than the achievable gray scale level data predicted that a decoding error becomes large. This configuration allows suppression or elimination of after-image noise.