Semiconductor OSD Controller with Dynamic Character Compression
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Solution Overview
Problem
Conventional timing controllers face limitations in flexibility for On Screen Display (OSD) functions due to limited ROM capacity and inability to dynamically update characters, and they experience undisplayable states during communication failures or interface issues, which are undesirable in reliable applications like automotive and medical displays.
Innovation Solution
A semiconductor apparatus with a video input interface, control input interface, encoder, decoder, and multiplexer for flexible OSD functionality, allowing dynamic character data compression and storage, and an abnormality detector to identify and respond to communication failures, enabling continued display functionality even in abnormal states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bitmap data for characters is stored in ROM, then the OSD function can be implemented, but the ROM capacity is limited and the number of pixels for characters cannot be increased
Solution Approach 1:
The patent extracts the character data storage function from ROM and relocates it to a separate external memory device. This allows the ROM to be used for other purposes while character data with higher resolution and more variety can be stored in the external memory, thereby increasing the number of pixels for characters without being constrained by ROM capacity.
Solution Approach 2:
The patent makes the memory system universal by allowing the same external memory to serve multiple functions: storing character data for OSD, storing image data, and storing other system data. This multi-functional approach resolves the contradiction by providing ample storage capacity for high-resolution characters while maintaining system efficiency.
2Adaptability or versatility
If bitmap data for characters is stored in ROM, then the OSD function can be implemented, but the characters cannot be corrected or added after product shipment
Solution Approach 1:
The patent transforms the static character storage system into a dynamic one by using writable external memory instead of read-only memory. This allows character data to be updated, corrected, or added after product shipment through software updates, providing continuous adaptability without requiring hardware changes or re-manufacturing.
Solution Approach 2:
The patent prepares the system for future updates by pre-configuring the external memory with initial character data while maintaining write capability. This preliminary setup allows the system to function immediately upon shipment while retaining the ability to be updated later, resolving the contradiction between ease of manufacture and adaptability.
3Productivity
If differential serial interface is used to connect timing controller and graphic controller, then data transmission can be achieved, but no image can be displayed during link establishment or disconnection
Solution Approach 1:
The patent implements beforehand cushioning by storing display data in advance in the external memory before it is needed. When the differential serial interface is establishing a link or experiences disconnection, the system can continue displaying images from the pre-stored data, preventing black screens and maintaining display availability during communication interruptions.
Solution Approach 2:
The patent introduces the external memory as an intermediary buffer between the graphic controller and display panel. This intermediary allows the display to continue operating using pre-fetched data even when the serial communication link is unavailable, thereby decoupling display availability from communication status and resolving the contradiction between productivity and reliability.
4Productivity
If link between timing controller and graphic controller is established, then image data can be transmitted, but any disconnection due to noise or failure results in undisplayable state
Solution Approach 1:
The patent changes the operational parameter of the display system from real-time continuous transmission dependency to buffered playback capability. By storing multiple frames or segments of image data in advance in external memory, the system can maintain display continuity even when transmission parameters fluctuate or connection is lost, resolving the contradiction between transmission productivity and display reliability.
Data Source
AI summary
A video input interface receives input video data in a normal state. A control input interface receives character data for On Screen Display (OSD) in a setup state. An encoder encodes the character data and stores encoded compressed data in a memory in the setup state. A decoder receives an instruction signal designating the character data to be displayed, reads, and decodes one piece of compressed data corresponding to the instruction signal from the memory, and reproduces the original character data in the normal state. A multiplexer superimposes character data on frame data and outputs the data.