Display Device Flicker Removal via PWM Current Continuity
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Solution Overview
Problem
Conventional display devices using PWM dimming techniques experience flickers due to frequent changes in input current, causing eye strain and potential eye diseases, and existing solutions complicate circuit design and increase costs.
Innovation Solution
A display device with a flicker removing module that adjusts the output current based on the duty cycle of a PWM signal, using a digital to analog conversion unit and voltage modulation to control input current continuity, eliminating frequency variations and reducing blue light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PWM dimming technique is used to control backlight brightness, then brightness adjustment capability is improved, but flickers occur causing eye strain and potential eye diseases
Solution Approach 1:
The patent introduces a flicker removing module as an intermediary component between the PWM backlight controller and the LED array. This module receives the PWM signal and converts it to a non-flickering form while maintaining brightness control capability, thereby eliminating the harmful flicker effect on human eyes while preserving the brightness adjustment function
Solution Approach 2:
The patent changes the electrical parameters of the backlight driving signal by converting from direct PWM dimming to a method that maintains continuous current flow. The flicker removing module adjusts the duty cycle of PWM signals and uses capacitive coupling to maintain continuous current through the LED array, changing the temporal characteristics of the current to eliminate flicker while preserving brightness control
2Object-affected harmful factors
If current control chip with I2C is used to replace PWM backlight controller for removing flickers, then flickers are removed, but circuit design becomes more complicated and manufacture cost increases
Solution Approach 1:
The patent makes the existing PWM backlight controller perform multiple functions by adding a simple flicker removing module. The original controller continues to handle brightness control via PWM, while the added module handles flicker removal, allowing the system to achieve both brightness adjustment and flicker elimination without requiring a completely different control chip
Solution Approach 2:
The patent uses inexpensive passive components (capacitors and resistors) in the flicker removing module instead of expensive specialized control chips. The solution employs simple RC circuits and capacitive coupling techniques that are cost-effective and easy to implement, avoiding the need for expensive I2C control chips while achieving the same flicker removal effect
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
The solution effectively reduces flickers and minimizes eye strain by maintaining continuous input current, allowing for adjustable backlight brightness without complex circuit designs, thereby reducing the burden on human eyes and potential eye diseases.
Implementation Method 1
a digital to analog conversion unit supplied with the PWM signal and the second voltage V2 and electrically connected between the voltage modulation unit and the resistance unit 160
Data Source
AI summary
A display device includes a backlight module, a backlight control module and a flicker removing module. The backlight module electrically connected between an input pin and an output pin which belong to the backlight control module, provides a backlight source to a display panel. The input pin receives a first voltage to control a continuity of an input current which is supplied to the backlight module and has no frequency variation. The flicker removing module electrically connected to the output pin receives a pulse width modulation signal and according to a duty cycle of the pulse width modulation signal, controls an output current outputted by the output pin, so as to control the backlight control module to control the input current according to the output current. The input current is associated with a backlight brightness of the backlight module.