White LED Optical Transmitter Waveform Correction
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Solution Overview
Problem
Current white LED-based data transmission systems face limitations in transmission speed due to the slow response time of fluorescent materials, high energy consumption, and high system costs, particularly with blue-light-excited and UV-excited white LEDs, leading to distortion and intersymbol interference.
Innovation Solution
An optical communication system that includes a light emitting device emitting a light signal with multiple wavelengths, a modulating circuit that peaks the electrical current, a detecting circuit to selectively detect a specific wavelength, and a waveform controlling circuit to correct the peaking based on the response time, minimizing waveform distortion and enabling high-speed transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a blue-light-excited white LED is used for data transmission, then the energy use efficiency is high and manufacturing cost is low, but the transmission speed is limited to several Mbps due to slow response time of fluorescent material
Solution Approach 1:
The patent segments the white light into multiple wavelength components using optical filters. By separating the blue light component (fast response) from the yellow fluorescent light (slow response), the system can selectively detect only the fast-response component for high-speed data transmission, while the fluorescent component provides good color rendering. This resolves the contradiction by dividing the light into functional segments with different response characteristics.
Solution Approach 2:
The patent applies local quality by using wavelength-selective detection. Instead of detecting all light components uniformly, the system selectively detects only the blue light component (specific wavelength range) that has fast response characteristics. This localized detection approach enables high-speed transmission while maintaining the benefits of fluorescent-based white LED.
2Reliability
If a UV-excited white LED or three-color-emitting white LED is used, then good color rendering properties are achieved, but the energy use efficiency is low and manufacturing cost is high
Solution Approach 1:
The patent makes the blue-light-excited white LED multi-functional by simultaneously using it for both high-speed data transmission and good color rendering. The same LED structure that provides fast response blue light also generates yellow fluorescent light for color rendering. The system achieves both functions through wavelength-selective detection and processing, eliminating the need for separate high-cost LED types.
3Productivity
If the intensity of light from the LED is modulated for data transmission, then data transmission is achieved, but waveform distortion and intersymbol interference occur due to slow response time
Solution Approach 1:
The patent extracts only the blue light component from the white light spectrum using optical filters. By removing the yellow fluorescent component that causes slow response and waveform distortion, the system achieves clean, undistorted waveforms suitable for high-speed data transmission. The extracted blue component has sufficiently fast response characteristics to avoid intersymbol interference.
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 system achieves high-speed and low-cost data transmission by selectively detecting and correcting the light signal component with a fast response time, reducing distortion and increasing transmission speed beyond the limitations of existing technologies.
Implementation Method 1
a light emitting device configured to, upon receiving an electrical current based on a transmission electrical signal, emit light and output a light signal including a plurality of wavelengths
Implementation Method 2
a fluorescent material such as YAG (yttrium aluminum garnet) is disposed around a blue LED, and the fluorescent material and the blue LED are packaged into one component. The light from the blue LED disposed at the center excites the fluorescent material so that the fluorescent material emits light that is complementary to blue light
Implementation Method 3
At a receiving end, the light is received by means of a photoelectric converter (O/E converter), such as a photodiode (PD), and is detected to achieve the data transmission
Data Source
AI summary
In one inventive aspect, a transmitter is provided. In the transmitter, a modulator supplies an electrical current based on a digital transmission electrical signal to a white LED, which emits light including a plurality of wavelengths into the air. A light detector separates a light signal component having a blue wavelength from the emitted light using an optical filter and converts the signal component to a monitoring electrical signal. A waveform control circuit outputs a control signal so that the time delay of the waveform of the monitoring signal with respect to the waveform of the transmission electrical signal is less than or equal to a predetermined value. The modulator corrects the amount of the electrical current supplied to the white LED on the basis of the control signal. In another inventive aspect, a receiver is provided. In the receiver, an optical filter separates a light signal component having a blue wavelength and a light detector detects substantially only the light signal component having a blue wavelength.