Semiconductor Light Source Control via Green Channel Amplitude Extraction
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Solution Overview
Problem
Existing semiconductor light source control systems face challenges in stabilizing and reliably controlling the current flowing in semiconductor light sources, particularly due to difficulties in accurately detecting and adjusting small detection voltages, which can lead to excessive power output and image quality deterioration.
Innovation Solution
A semiconductor light source control apparatus that includes a detection resistor, a power supply current control apparatus, and a DC/DC converter, which pulse-width-modulates the current for specific color intervals to adjust brightness and tone, with the amplitude control focused on the green interval to maximize duty value, thereby simplifying and stabilizing current control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If PWM is applied to control current amplitude for all color intervals, then brightness and color tone can be adjusted, but control complexity increases and stability decreases
Solution Approach 1:
The patent extracts the amplitude control function from the PWM control and applies it only to the green channel, separating the control mechanisms. The green channel current amplitude is controlled independently via DC/DC converter, while red and blue channels use only PWM duty cycle control. This extraction simplifies the overall control system while maintaining stability.
Solution Approach 2:
The patent applies different control strategies to different color channels based on their specific requirements. The green channel, which requires maximum duty value and stable amplitude, receives specialized amplitude control. The red and blue channels use standard PWM control. This localized differentiation optimizes each channel's performance without complicating the entire system.
2Measurement precision
If detection voltage is used to control current, then current detection is enabled, but excessive power output may occur leading to image quality deterioration
Solution Approach 1:
The patent implements a feedback control mechanism where the detection voltage from the detection resistor is fed back to the control apparatus. The control apparatus adjusts the DC/DC converter based on this feedback to maintain accurate current levels. This prevents excessive power output by continuously monitoring and correcting current deviations, thereby protecting image quality.
3Productivity
If PWM duty value is maximized for green interval, then brightness control is optimized, but control complexity at color interval boundaries increases
Solution Approach 1:
The patent extracts the amplitude control from PWM and applies it specifically to the green channel, allowing the green PWM duty value to be maximized for optimal brightness control. This separation eliminates the need to reduce green PWM duty to accommodate amplitude variations, simplifying control at color interval boundaries while maintaining high brightness control efficiency.
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 allows for stable and reliable control of the current in semiconductor light sources, reducing the risk of excessive power output and improving image quality by minimizing the need for frequent adjustments at color interval boundaries.
Implementation Method 1
a detection resistor that generates a detection voltage by the current flowing in the semiconductor light source
Implementation Method 2
a semiconductor light source that emits light in accordance with a current
Data Source
AI summary
A semiconductor light source control apparatus includes a semiconductor light source that emits light in accordance with a current, a detection resistor that generates a detection voltage by the current flowing in the semiconductor light source; and a power supply current control apparatus that controls the current flowing in the semiconductor light source based on the detection voltage. The semiconductor light source control apparatus pulse-width-modulates (PWM) the current flowing in the semiconductor light source for respective ones of a plurality of color intervals to adjust brightness and color tone of output light from the semiconductor light source. An amplitude of the current flowing in the semiconductor light source is controlled only in a predetermined color interval when a duty value of the PWM is maximum.