Projection Light Source Controller Timing and Power Modulation
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Solution Overview
Problem
Existing projection technologies face challenges in achieving high brightness and color reproducibility due to the limitations of fluorescent substance saturation and varying emission efficiencies across different colors, leading to insufficient light output or reduced luminous efficiency.
Innovation Solution
A light source unit comprising a light source, a light-source light generator, and a controller that time-shares the emission of light across multiple colors with different luminous efficiencies, adjusting the light-emitting periods and drive power to optimize brightness and color reproduction, using a combination of light sources such as semiconductor lasers and LEDs with a color wheel featuring fluorescent and non-fluorescent areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If excitation light per unit area is increased to obtain sufficient absolute light quantity, then brightness is improved, but luminous efficiency of the fluorescent substance is decreased due to saturation
Solution Approach 1:
The invention dynamically adjusts the light-emitting period and drive power of the light source based on the luminous efficiency characteristics of different colored fluorescent substances. By making the excitation conditions variable rather than fixed, the system optimizes brightness output while preventing saturation-induced efficiency losses for each color channel independently
Solution Approach 2:
The invention changes the parameters of excitation light (emitting period and drive power) to match the specific luminous efficiency characteristics of each fluorescent substance. By adjusting these parameters within a controllable range, the system achieves optimal balance between brightness and luminous efficiency for red, green, and blue light sources with different efficiency profiles
2Loss of energy
If excitation light per unit area is decreased to avoid saturation of fluorescent substance, then luminous efficiency is improved, but absolute quantity of light becomes insufficient
Solution Approach 1:
The system dynamically balances excitation light intensity and emission duration for each color channel. By making the light-emitting period adjustable, the system can compensate for lower instantaneous intensity with longer duration, maintaining sufficient absolute light quantity while operating in the high-efficiency non-saturated region
Solution Approach 2:
The invention uses periodic modulation of the light source with different duty cycles for different colors. By controlling the light-emitting period separately for each wavelength, the system accumulates sufficient light output over time while keeping peak excitation intensity low enough to avoid fluorescent substance saturation
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 enables the projection of bright images with high color reproducibility by balancing light output and preventing fluorescent substance saturation, while also considering the distinct luminous efficiencies of different colors and light sources.
Implementation Method 1
a light source configured to emit light in a predetermined wavelength range
Implementation Method 2
a color wheel which has a fluorescent layer formed on the back side for emitting visible light corresponding to each of red, green, and blue light by radiating ultraviolet light
Data Source
AI summary
A light source controller is configured to control timings of driving the first and second light sources and the light-source light generator, so that the light-source light of two or more colors generated by the light-source light generator and the light-source light emitted from the second light source are cyclically generated, by setting a light-emitting period of at least one light-source light color having a higher luminous efficiency out of the two or more colors generated by the light-source light generator, shorter than those of the other light-source light colors, and setting a drive power of the first light source during generation of the light-source light color whose light-emitting period is set short, greater than a drive power of the first light source during generation of the other light-source light colors.