Light Source Cooling for Image Display Devices
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Solution Overview
Problem
Existing image display devices with high pressure mercury lamps face issues such as the photo-darkening phenomenon and temperature deviations when switching between energy saving and regular modes, leading to potential glass tube explosion, permeability deterioration, and discomfort due to sudden brightness changes.
Innovation Solution
An image display device with a control system that automatically adjusts power supply and cooling fan airflow based on image signal luminance, using tables to manage power and fan rotation changes at constant rates to maintain optimal temperature and prevent these issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling fan operates at full speed in energy saving mode to cool the light source, then the light source temperature is controlled, but the photo-darkening phenomenon occurs due to excessive cooling
Solution Approach 1:
The cooling fan speed is made dynamic and adjustable based on operating mode. The system switches between full speed (regular mode) and reduced speed (energy saving mode), allowing the cooling intensity to adapt to the reduced power consumption and lower heat generation in energy saving mode, thereby preventing excessive cooling and photo-darkening.
Solution Approach 2:
The operating parameters of the cooling fan (rotation speed) are changed according to the power supply mode. When transitioning from regular mode to energy saving mode, the fan speed parameter is reduced to match the lower heat generation, maintaining optimal temperature without causing photo-darkening.
2Speed
If power supplied to the light source is suddenly increased or decreased when switching modes, then the light source adapts quickly, but the screen brightness changes suddenly causing user discomfort
Solution Approach 1:
The system performs preliminary gradual adjustment of power supply before completing the mode switch. By incrementally changing the power level rather than making an abrupt transition, the light source brightness changes smoothly, preventing sudden brightness shifts that would cause user discomfort while still achieving the desired mode transition.
3Device complexity
If the cooling fan speed is not adjusted when switching to energy saving mode, then the system structure remains simple, but the light source is excessively cooled causing photo-darkening
Solution Approach 1:
The control system automatically adjusts the cooling fan speed based on the detected power supply mode without requiring manual intervention. The system monitors its own operating state and self-regulates the cooling intensity, maintaining simplicity in user interaction while preventing photo-darkening through automatic adaptation.
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 solution ensures stable temperature ranges, preventing glass tube explosion, permeability deterioration, and photo-darkening, while minimizing user discomfort from sudden brightness changes by smoothly adjusting power and airflow.
Implementation Method 1
a cooling fan that cools said light source
Implementation Method 2
a high pressure mercury lamp or the like as a light source
Data Source
AI summary
An image determination section determines whether an input image signal represents a bright image or a dark image. A control section switches between a first lighting mode in which the output of a power supply section is a first power value and a second lighting mode in which the output of power supply section is a second power value based on the determined result of the image determination section. The control section refers to a first table that contains data representing the relationship between the power value of the power supply section and the number of rotations of a cooling fan in the case in which the output of the power supply section is increased from the second power value to the first power value at a constant rate when the second lighting mode is switched to the first lighting mode.