LED Drive Pulse Modulation for Linear Gamma and High Refresh Rate
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Solution Overview
Problem
Traditional LED driving chips face challenges in maintaining a high visual refresh rate and linear gamma value when displaying low gray scale brightness, leading to potential loss of frame time and non-linear gamma values, which affect the display's clarity and color accuracy.
Innovation Solution
The method involves calculating a display period based on set sub-periods and gclk per line, adjusting these parameters if necessary to ensure the display period is within the frame rate time, and converting and dividing gray data to ensure even distribution and linear gamma values, using a device with modules for calculation, conversion, division, and adjustment to achieve these steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PWM frequency is reduced to increase gray level, then gray level is improved, but refresh rate deteriorates
Solution Approach 1:
The patent segments the PWM period into multiple sub-periods, where each sub-period carries a portion of the gray level information. By dividing the overall gray level into multiple smaller increments distributed across sub-periods, the system achieves high gray level precision without requiring a low PWM frequency, thus maintaining high refresh rate.
2Manufacturing precision
If LED light-emitting time is shortened for low gray scale brightness, then gray scale control is improved, but visual refresh rate deteriorates
Solution Approach 1:
The patent employs periodic sub-periods within each PWM cycle, where multiple sub-periods are repeated to convey the same gray level information. This periodic structure allows the system to maintain short light-emitting times for low gray scale while ensuring the information is transmitted repeatedly, thereby preserving visual refresh rate and preventing flicker.
3Productivity
If frame rate time is reduced to increase refresh rate, then refresh rate is improved, but display period accuracy deteriorates
Solution Approach 1:
The patent dynamically adjusts parameters such as the number of sub-periods per PWM cycle and the time allocation for each sub-period to fit within the frame rate time constraint. By changing these parameters adaptively, the system maintains high refresh rate while ensuring accurate display period timing and preventing frame synchronization issues.
Data Source
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AI summary
The present application provides a method of LED driving pulse modulation, comprising the following steps: calculating a display period according to a set number of sub-period, a set number of gclk per line and a set number of line scan; converting input gray data according to a set number of gray level; dividing the converted gray data according to the number of sub-period, the number of gclk per line, and a composite number to obtain high-gray data, low-gray data, and compensation data; and calculating a number of gray level that needs to be displayed in a current sub-period according to the high-gray data, the low-gray data, and the compensation data. With the method of LED driving pulse modulation of the present application, any number of sub-period and any number of gclk per line can be set to solve the problem of non-linear gamma, and make the display effect more delicate and true.