Display Current Limiting Circuit for Power and Gamma Control
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Solution Overview
Problem
In display apparatuses, especially those with larger panels, the increase in size leads to higher power consumption, and existing methods to control power consumption, such as those described in PTL 1, result in varying gamma characteristics and reduced image quality due to constant light emission waveform rises during non-lighting periods, independent of signal levels.
Innovation Solution
A display apparatus and current limiting method that includes a current limiting circuit with a gain computation circuit to calculate a screen power value and determine a gain based on pixel values, and a lighting control circuit to adjust the lighting state of pixels according to a predicted power value, ensuring power consumption is reduced to a control target value while maintaining image quality by varying the gain and controlling lighting states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel size is increased, then the display area is improved, but the power consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the non-lighting period duration based on the video signal content. The lighting control circuit computes power consumption from video signal statistics and varies the non-lighting period length to maintain power consumption within target limits while preserving gamma characteristics and image quality across different display scenarios
2Use of energy by moving object
If a non-lighting period is extended to suppress power consumption, then the power consumption is reduced, but the gamma characteristics vary and image quality deteriorates
Solution Approach 1:
The patent implements dynamics by making the non-lighting period duration variable rather than fixed. The lighting control circuit dynamically adjusts the non-lighting period length based on real-time power consumption computations from video signal statistics, allowing the system to adapt to different content requirements and maintain consistent gamma characteristics across varying display conditions
Solution Approach 2:
The patent applies feedback by using power consumption information derived from video signal statistics to control the lighting state. The lighting control circuit continuously monitors video signal characteristics, computes expected power consumption, and adjusts the non-lighting period duration accordingly to maintain power consumption within target limits while preserving image quality
3Use of energy by moving object
If the current is limited uniformly across all pixels, then the power consumption is suppressed, but the image quality is reduced
Solution Approach 1:
The patent applies local quality by implementing row-by-row or block-by-block lighting control rather than uniform control across the entire display panel. The lighting control circuit can apply different lighting states to different regions based on local power consumption requirements, allowing high-quality display in areas requiring it while suppressing power consumption in less critical areas
Data Source
AI summary
A display apparatus includes a display panel including a plurality of pixels, and a current limiting circuit that limits current consumption in the plurality of pixels, the current limiting circuit includes a gain computation circuit that computes a screen power value in reference to a pixel value included in a video signal and that determines a gain in reference to the screen power value, and a gain multiplication circuit that multiplies the pixel value by the gain and that outputs a limit signal including the pixel value multiplied by the gain, the display panel includes a display unit, and a lighting control circuit that controls a lighting state of the plurality of pixels in reference to a predicted power value computed according to the limit signal, to reduce a power consumption value in the plurality of pixels to a value equal to or smaller than a control target power value, the gain is 1 when the screen power value is equal to or smaller than the control target power value, and the gain is a value equal to or smaller than a value obtained by dividing the control target power value by the screen power value, in other cases.