OLED Driving Circuit Brightness Control Without Frame Memory
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Solution Overview
Problem
Existing display devices with OLED elements face challenges in reducing power consumption and extending the lifetime of the elements, particularly when displaying bright images, as they require frame memory for accurate brightness control, which increases costs and circuit complexity, and omitting frame memory leads to delayed response and degradation in display quality.
Innovation Solution
A driving device that calculates the sum or average of pixel data for each horizontal scan line, predicts the brightness of subsequent frames based on previous frames, and applies a brightness reduction ratio to limit the current, allowing for real-time brightness control without frame memory, thereby reducing power consumption and maintaining display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If frame memory is provided for accurate brightness control, then power consumption reduction and lifetime extension are achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the frame memory component from the system by implementing a frame memoryless brightness control method. The brightness limitation is achieved by comparing current frame pixel data with previously limited pixel data directly, eliminating the need for dedicated frame memory while maintaining power consumption reduction and lifetime extension benefits
Solution Approach 2:
The patent uses a copy of previously limited pixel data (from the previous frame) as a reference for brightness control. By comparing current frame data with the previously limited data copy, the system achieves accurate brightness limitation without requiring storage of the entire original frame buffer, thus reducing circuit complexity
2Device complexity
If frame memory is omitted to reduce circuit size and cost, then device complexity is reduced, but response speed decreases and display quality degrades
Solution Approach 1:
The patent applies preliminary brightness limitation to the previous frame's pixel data before display. This pre-limited data is then used as a reference for controlling the current frame's brightness, enabling rapid response without frame memory by leveraging pre-processed data from the previous frame
Solution Approach 2:
The patent implements dynamic brightness control by continuously comparing current frame pixel data with previously limited data and adjusting the brightness limitation in real-time. This dynamic approach maintains high response speed and display quality without requiring static frame memory storage
3Illumination intensity
If brightness is not limited, then display quality is maintained, but power consumption increases and element lifetime decreases
Solution Approach 1:
The patent implements a feedback mechanism where the brightness limitation applied to the previous frame is used as feedback to control the current frame's brightness. By continuously monitoring and adjusting based on previously limited data, the system maintains appropriate display luminance while limiting power consumption and extending element lifetime
Solution Approach 2:
The patent changes the brightness parameter dynamically by applying brightness limitation ratios based on comparisons between current and previously limited pixel data. This parameter adjustment maintains display quality within acceptable ranges while reducing power consumption and protecting OLED element lifetime
Data Source
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AI summary
A driving method of a display device in which an image is displayed on a display panel having a display element arranged in a pixel matrix, includes comparing, among pixel data corresponding to a display content in each pixel, pixel data corresponding to an nth horizontal scan line of an Nth frame and pixel data corresponding to an nth horizontal scan line of an (N-1)th frame; and setting a brightness reduction ratio with respect to pixel data corresponding to the nth horizontal scan line of the Nth frame or a later horizontal scan line of the Nth frame based as a function of the comparison and all pixel data corresponding to the (N-1)th frame or all pixel data from the nth horizontal scan line of the (N-1)th frame to an (n-1)th horizontal scan line of the Nth frame and controlling power supplied.