Graphene Visible Light Communication Using Colour Shift Keying
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Solution Overview
Problem
Traditional visible light communication systems using three or four base colours suffer from power inefficiency and limited symbol representation due to the need for mixing light from multiple LEDs and the use of colour filters in photodetectors, which restricts the range of colours and increases signal noise.
Innovation Solution
A visible light communication system employing at least six graphene-based light emitting devices with tunable peak transmission wavelengths and corresponding graphene-based photodetectors with adjustable peak reception wavelengths, enabling a wider colour constellation and improved signal-to-noise ratio through colour shift keying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional photodetectors with colour filters are used to receive visible light, then the waveband can be defined corresponding to peak transmission wavelengths, but the signal-to-noise ratio deteriorates and the range of wavelengths that can be received is limited
Solution Approach 1:
The patent extracts and removes the colour filter component from the photodetector system. By eliminating the colour filter, the system avoids the noise and wavelength limitations introduced by the filter while maintaining the ability to receive and differentiate visible light wavelengths through the graphene-based photodetector's inherent spectral response characteristics
Solution Approach 2:
The patent employs graphene-based photodetectors that utilize the unique properties of graphene material to achieve broad spectral response. The graphene-based structure provides enhanced electron-hole pair generation and separation across a wide wavelength range, improving signal-to-noise ratio while maintaining wavelength discrimination capability through material-specific optical properties
2Device complexity
If only three or four base colours are used in colour shift keying, then the system can be implemented with tri-LED or quad-LED configurations, but the number of representable symbols is limited and power efficiency deteriorates
Solution Approach 1:
The patent employs dynamically controllable graphene-based light emitting devices whose emission wavelengths can be tuned by adjusting gate voltage or other operational parameters. This dynamic wavelength control enables the system to access a continuous spectrum of colours rather than being restricted to fixed wavelengths, dramatically increasing the number of representable symbols while maintaining a compact device configuration
Solution Approach 2:
The patent changes the operational parameters of the light emitting devices by utilizing electrically tunable graphene-based materials. By varying parameters such as gate voltage, carrier concentration, or material composition, the emission wavelength can be continuously adjusted across the visible spectrum, enabling dense wavelength division multiplexing and significantly expanding symbol capacity without increasing the number of physical LEDs
3Illumination intensity
If mixed colours are generated by combining multiple LEDs, then the desired colour can be achieved, but power efficiency deteriorates since at least two LEDs are required instead of a single LED
Solution Approach 1:
The patent makes each graphene-based light emitting device universally capable of emitting multiple wavelengths by enabling dynamic wavelength tuning through electrical control. A single device can be programmed to emit at different wavelengths on demand, replacing the need for multiple fixed-wavelength LEDs and their corresponding mixing arrangements, thereby achieving full colour generation capability with a single multi-functional device
Solution Approach 2:
The patent utilizes the ability to change the emission wavelength parameter of graphene-based light emitting devices through electrical tuning. By adjusting operational parameters such as gate voltage or carrier density, a single LED can dynamically shift its emission wavelength across the visible spectrum, eliminating the need for multiple LEDs and reducing power consumption associated with driving multiple devices and mixing their outputs
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 configuration enhances transmission power efficiency, reduces symbol error rates, and increases the number of symbols that can be represented, while improving the signal-to-noise ratio compared to traditional systems.
Implementation Method 1
at least six field effect light emitting devices, each having a respective peak transmission wavelength
Implementation Method 2
graphene-based light emitting devices
Implementation Method 3
at least six graphene-based photodetectors, each having a respective peak reception wavelength
Implementation Method 4
Plasmon resonance enhanced multicolour photodetection by graphene
Data Source
AI summary
The present disclosure provides a visible light communication transmitter, a visible light communication receiver, a visible light communication system, and a method of visible light communication, which are suitable for colour shift keying (CSK), as well as providing a method of CSK. The transmitter comprises at least six graphene-based light emitting devices of different peak transmission wavelengths from each other. The receiver comprises a corresponding number of graphene-based photodetectors of different peak reception wavelengths from each other. A system according to the disclosure comprises such a transmitter and such a receiver, wherein each respective one of the different peak reception wavelengths of the six graphene-based photodetectors corresponds to a respective one of the different peak transmission wavelengths of the graphene-based light emitting devices. Such a system allows a method of visible light communication with a colour constellation of at least six base colours.