Display Backlight Transition Control Between DC and PWM Dimming
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Solution Overview
Problem
Existing backlight adjustment methods in terminal devices cause abrupt changes in screen brightness during transitions between DC and PWM dimming strategies, leading to flicker issues.
Innovation Solution
Implement a method that adds a transition backlight value within a preset interval during transitions between DC and PWM dimming strategies, ensuring smooth brightness adjustments by replacing or buffering backlight values as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the terminal device directly switches between DC dimming strategy and PWM dimming strategy to adjust backlight brightness, then the backlight adjustment range is improved, but the screen brightness changes abruptly causing flicker issues
Solution Approach 1:
The patent introduces a transition backlight value as an intermediary between DC and PWM dimming strategies. When switching from DC to PWM dimming, the system first sets a transition backlight value within a preset interval, then gradually adjusts to the target PWM backlight value. This intermediary approach prevents abrupt brightness changes while maintaining the full adjustment range of both dimming strategies.
Solution Approach 2:
The patent performs preliminary action by pre-setting a transition backlight value before completing the dimming strategy switch. The transition backlight value is calculated based on the current DC backlight value and the target PWM backlight value, ensuring that the brightness transition starts from a stable intermediate point rather than jumping directly between disparate brightness levels.
2Measurement precision
If the terminal device uses DC dimming strategy for high brightness adjustment, then the brightness control precision is improved, but the transition to low brightness causes abrupt changes
Solution Approach 1:
The transition backlight value serves as a mediator between high-precision DC dimming control and PWM dimming control. By introducing this intermediate state, the system maintains the precision benefits of DC dimming at higher brightness levels while preventing the harmful abrupt changes that would occur during direct transition to PWM dimming at lower brightness levels.
Solution Approach 2:
The patent changes the backlight control parameter from direct DC current adjustment to a two-stage process: first setting a transition backlight value (parameter interpolation), then adjusting to the final PWM duty cycle. This parameter transformation approach allows smooth transition while preserving the precision control characteristics of DC dimming.
3Use of energy by moving object
If the terminal device uses PWM dimming strategy for low brightness adjustment, then the energy consumption is reduced, but the transition from high brightness causes flicker
Solution Approach 1:
The transition backlight value acts as a buffer that mediates between the energy-efficient PWM dimming state and the stable DC dimming state. By introducing this intermediate transition state, the system can switch to energy-saving PWM mode while preventing the flicker that would result from direct transition, thus achieving both energy reduction and brightness stability.
Solution Approach 2:
The system performs preliminary action by establishing a transition backlight value before fully engaging PWM dimming. This preliminary state ensures that when the device switches to energy-saving PWM mode, the brightness transition is smooth and stable, avoiding flicker while still achieving the energy consumption benefits of PWM dimming.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach alleviates abrupt brightness changes, providing a smoother transition and improved visual experience by maintaining stable backlight values.
Implementation Method 1
a driving current flowing through an organic light-emitting material is reduced to control light-emitting efficiency
Implementation Method 2
The terminal device performs backlight adjustment by using a PWM dimming strategy when the terminal device detects that the backlight brightness is within a range from the mid-low screen brightness to lowest screen brightness. For example, the backlight brightness is adjusted by reducing a screen-on ratio, that is, a duty (duty) value.
Data Source
AI summary
An embodiment of this application provides a backlight adjustment method. The method includes: A terminal device first obtains an undelivered second backlight value before displaying an image. When the second backlight value is not equal to a first backlight value of the terminal device when a previous image frame is displayed, the terminal device replaces the second backlight value with a preset backlight value if the second backlight value is greater than the preset backlight value and the first backlight value is less than the preset backlight value or the second backlight value is less than the preset backlight value and the first backlight value is greater than the preset backlight value, and displays the image based on the preset backlight value, to add transition backlight during transition between a DC dimming strategy and a PWM dimming strategy.