UV LED Control for Projection Light Sources
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Solution Overview
Problem
Current light source systems in projection systems, which use UHP lamps or LEDs with wavelength conversion, suffer from high power consumption, UV light wastage, and additional costs due to the need for UV filters to prevent eye harm when UV light is not utilized.
Innovation Solution
A control method and apparatus that monitors the position of a color wheel to shut off the UV light source when the blue segment is illuminated, reducing power consumption and avoiding eye harm, while pulse driving the UV source to extend its lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If UV LEDs are used together with blue LEDs to excite phosphors to increase luminance, then the luminance of output light is increased, but UV light is wasted and additional UV filters are needed to prevent eye harm
Solution Approach 1:
The patent applies periodic action by controlling the UV LED to operate in pulsed mode rather than continuously. The control unit turns the UV LED on and off periodically based on the position of the color wheel, specifically activating it only when a phosphor segment requiring UV excitation is in the light path. This periodic operation eliminates UV light wastage while maintaining the ability to generate high luminance when needed.
Solution Approach 2:
The patent implements feedback control through a position detection apparatus that monitors the color wheel's position and provides feedback to the control unit. This feedback mechanism enables the control unit to make real-time decisions about UV LED activation, turning it on only when necessary (when a phosphor segment is in position) and off when not needed (when the blue LED segment is in position), thereby eliminating energy wastage while maintaining illumination intensity when required.
2Object-affected harmful factors
If UV filters are added to prevent UV light from passing through and harming eyes, then eye safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies the extraction principle by removing the need for UV filters through a different approach. Instead of adding filtering components to block UV light, the system extracts or eliminates the source of harmful UV light by controlling the UV LED to operate only when necessary. The control unit shuts off the UV LED when the blue LED segment is in the light path, thereby eliminating UV exposure without requiring any filtering hardware.
Solution Approach 2:
The patent implements self-service through an integrated control system that automatically manages UV LED operation based on color wheel position feedback. The control unit receives position information from the detection apparatus and autonomously decides when to activate or deactivate the UV LED, eliminating the need for external UV filtering mechanisms. The system serves its own safety needs through intelligent control rather than additional passive components.
3Reliability
If the UV LED is continuously on to ensure sufficient UV light for phosphor excitation, then phosphor excitation is adequate, but power consumption increases and LED lifetime decreases
Solution Approach 1:
The patent applies periodic action by operating the UV LED in pulsed mode rather than continuously. The control unit activates the UV LED only during specific time intervals when the color wheel positions a phosphor segment that requires UV excitation in the light path. This periodic operation ensures adequate phosphor excitation occurs when needed while dramatically reducing overall power consumption and extending LED lifetime through reduced cumulative operating time.
Solution Approach 2:
The patent implements feedback control where the position detection apparatus continuously monitors the color wheel position and provides real-time feedback to the control unit. Based on this feedback, the control unit intelligently activates the UV LED only when a phosphor segment is in the light path requiring UV excitation, and shuts it off when not needed. This feedback-driven approach ensures adequate phosphor excitation while minimizing power consumption and extending LED operational life.
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 reduces power consumption by about half, saves costs, and increases the UV light source's lifetime by ensuring it is only active when necessary, with the UV light being effectively utilized.
Implementation Method 1
the first light emitting source is a blue LED
Implementation Method 2
the second light emitting source is UV LEDs
Implementation Method 3
UV LEDs can be used together with blue LEDs to excite the phosphors in a LED based light source
Implementation Method 4
a color-adjusting apparatus with segments of at least two different light wavelength conversion characteristics
Data Source
AI summary
A light source includes a first light emitting source (2), a second light emitting source (3), a color-adjusting apparatus (1) with light wavelength conversion material, a control unit, and a positioning apparatus provided on the color-adjusting apparatus (1). The positioning apparatus sends a positioning signal which indicates a position of the color-adjusting apparatus to the control unit. The control unit outputs a control signal to the power switch of the second light emitting source so that the second light emitting source is controlled to stop emitting the light when the light generated by the color-adjusting apparatus is the same as that of the first light emitting source. A control method for light source and a projection system having light source are also disclosed.