Projector Light Source Power Control for Startup Brightness
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Solution Overview
Problem
Projectors using LED or LD light sources face the issue of excessively bright reflected light at startup, even when ambient conditions are bright, due to the maximum light emission from the start, leading to unnecessary power reduction for pre-projection images.
Innovation Solution
A projector system with a light source, power supply, projection unit, detection means for ambient light, and control unit that increments power supply based on detected ambient light intensity to adjust light output accordingly, ensuring appropriate brightness reduction at startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the light source emits light at maximum light quantity from the start, then the light output is maximized, but the reflected light on the projection surface appears excessively bright at startup
Solution Approach 1:
The light source driving power is made dynamic rather than static. The control unit adjusts the driving power of the light source based on detected screen luminance, incrementally increasing power until the projection image reaches maximum brightness. This dynamic adjustment resolves the contradiction by allowing the system to start with reduced brightness (avoiding excessive reflected light) and progressively reach maximum power output.
Solution Approach 2:
A feedback mechanism is implemented where the detection unit continuously monitors the luminance of the projection surface and provides this information to the control unit. The control unit uses this feedback to adjust the light source driving power in real-time, creating a closed-loop control system that balances light output with reflected light brightness, thereby resolving the technical contradiction.
2Object-affected harmful factors
If a pre-projection image is projected at lower light quantity before the projection image, then the reflected light brightness is reduced, but an unnecessary process is performed when ambient light is already bright
Solution Approach 1:
The system performs self-assessment by using the detection unit to automatically evaluate the current screen luminance conditions. Based on this self-detected information, the control unit autonomously decides whether to implement the incremental power increase process or start directly at maximum power, eliminating the need for manual intervention or fixed pre-projection sequences regardless of ambient conditions.
Solution Approach 2:
The system changes the operating parameter (light source driving power) based on detected environmental conditions (screen luminance). When ambient light is bright and screen luminance is already high, the system skips the incremental power increase and starts at maximum power. When ambient light is dark, it uses the incremental approach. This conditional parameter adjustment resolves the contradiction between reducing reflected light and maintaining productivity.
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 effectively controls light source power to reduce brightness of reflected light at startup, optimizing light output according to usage conditions and preventing excessive brightness perception.
Implementation Method 1
LEDs (Light Emitting Diodes) and LDs (Laser Diodes) that are made up from semiconductor elements are in many cases used as the light sources of projectors
Implementation Method 2
LEDs (Light Emitting Diodes) and LDs (Laser Diodes) that are made up from semiconductor elements are in many cases used as the light sources of projectors
Implementation Method 3
detection means that detects the intensity of ambient light of the projection surface
Data Source
AI summary
With the purpose of controlling a light source to appropriately reduce the brightness of reflected light at the time of starting projection according to the conditions under which a projector is being used, the projector includes a solid-state light source unit that emits light, a power supply unit that supplies driving electric power to the solid-state light source unit, an image display device that modulates the light emitted from the solid-state light source unit according to an image signal and that projects the modulated light onto a projection surface, and a detection unit that detects the intensity of the ambient light of the projection surface.