Backlight Driver Voltage Control for Visible Light Communication
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Solution Overview
Problem
Liquid crystal displays require a separate light source, such as a backlight unit, for image display, leading to issues like flicker and non-uniform brightness during data transmission using visible light communication.
Innovation Solution
A display apparatus with a backlight driver that controls the voltage level of the driving voltage based on the number of turn-on periods during communication periods, ensuring uniform brightness and reducing flicker by adjusting the voltage level inversely proportional to the duty ratio of the turn-on periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the backlight is turned on and off during communication period to transmit data using visible light communication, then data transmission capability is improved, but display quality deteriorates due to flicker and non-uniform brightness
Solution Approach 1:
The backlight is driven with periodic on-off cycles during communication periods to encode data transmission. The driver controller applies driving voltages with specific duty ratios that correspond to data bits, creating periodic light emission patterns that convey information while maintaining controlled brightness characteristics
Solution Approach 2:
The driver controller dynamically adjusts the duty ratio parameter of the backlight driving voltage based on the number of turn-on periods during communication periods. By changing the duty ratio parameter, the system achieves both data transmission through visible light modulation and compensation for brightness non-uniformity, resolving the contradiction between communication capability and display quality
2Adaptability or versatility
If the backlight is turned on and off during communication period, then data transmission is enabled, but brightness uniformity across multiple communication periods deteriorates
Solution Approach 1:
The driver controller monitors the number of turn-on periods of the backlight during each communication period and uses this information as feedback to adjust the duty ratio for subsequent communication periods. This feedback mechanism ensures that brightness uniformity is maintained across multiple communication periods while continuing to enable data transmission through light modulation
Solution Approach 2:
The system dynamically adjusts the duty ratio of the backlight driving voltage based on real-time communication period characteristics. The duty ratio is not fixed but varies adaptively to compensate for brightness differences that occur during different communication periods, thereby maintaining overall brightness consistency while preserving communication functionality
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 brightness differences and prevents flicker during data transmission, improving display quality and increasing the intensity and transmission distance of the light.
Implementation Method 1
a backlight which provides the light to the display panel in response to a driving voltage
Implementation Method 2
The backlight is turned on and off during a communication period to transmit data to an external receiver using visible light communication during the communication period
Data Source
AI summary
A display apparatus includes a display panel which receives a light, a backlight which provides the light to the display panel in response to a driving voltage, and a backlight driver which applies the driving voltage to the backlight. The backlight is turned on and off during a communication period to transmit data to an external receiver using visible light communication during the communication period. The backlight driver controls a voltage level of the driving voltage according to a number of turn-on periods of the driving voltage during the communication period.