Projector Cooling System with Time-Dependent Temperature Threshold
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Solution Overview
Problem
Image projection apparatuses face issues with mistaken activation or inactivation of protection functions due to residual heat after the light source is turned off, leading to inefficient heat management and potential thermal damage, especially when the exhaust air outlet is blocked.
Innovation Solution
Incorporating a temperature detector and controller that adjust the predetermined temperature threshold based on elapsed time since the power is turned on or the light source was turned off, to accurately determine temperature abnormalities and prevent false protection activations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed temperature threshold is used for protection activation, then the protection function can be activated when temperature exceeds the threshold, but the protection function is mistakenly activated during re-lighting due to residual heat
Solution Approach 1:
The patent applies dynamics by changing the temperature threshold from a fixed value to a dynamic value that varies with time. The controller adjusts the threshold based on the elapsed time since the light source was turned off, making the protection system adaptive to the thermal state of the apparatus. This resolves the contradiction by enabling accurate protection activation while accounting for residual heat during re-lighting operations.
Solution Approach 2:
The patent changes the parameter of the temperature threshold from a constant to a time-dependent variable. By introducing time as a variable parameter, the system can distinguish between normal residual heat elevation during re-lighting and abnormal temperature rises indicating cooling system failure. This parameter change enables reliable protection activation without false positives.
2Reliability
If a fixed temperature increase rate threshold is used, then the protection function can detect abnormal heating, but the protection function is not activated during blocked exhaust due to lower increase rate from high initial temperature
Solution Approach 1:
The patent applies dynamics by making the temperature increase rate threshold time-dependent rather than fixed. The threshold is adjusted based on the elapsed time since power-on or light-source shutdown, allowing the system to account for the thermal history and residual heat conditions. This enables reliable detection of abnormal heating rates while avoiding false negatives during re-lighting operations.
3Adaptability or versatility
If the exhaust air outlet is blocked, then the projector can be used in various positions, but heat exhaust efficiency deteriorates causing excessive temperature increase
Solution Approach 1:
The patent implements feedback by continuously monitoring the internal temperature and comparing it against the time-dependent threshold. When the temperature exceeds the threshold, the controller activates protection operations such as warning messages or shutdown. This feedback mechanism enables the system to operate in various positions including blocked exhaust scenarios while maintaining safe operating temperatures through active monitoring and protective responses.
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 solution effectively prevents unnecessary protection operations and ensures accurate heat management by dynamically adjusting temperature thresholds, thereby avoiding thermal damage and maintaining the projector's performance and longevity.
Implementation Method 1
a temperature detector that detects a temperature inside of the apparatus
Implementation Method 2
a light source cooling fan that blows air toward the light source
Implementation Method 3
a heat sink that is in contact with the light source
Implementation Method 4
exhausts the airflows taking heat from the heat generating devices through an exhaust air outlet to the outside
Data Source
AI summary
The image projection apparatus includes a temperature detector that detects a temperature inside of the apparatus, and a controller that performs a protection operation when the temperature detected by the temperature detector is higher than a predetermined temperature. The controller measures an elapsed time from when a power of the apparatus is turned on, and changes the predetermined temperature in accordance with the elapsed time. This apparatus can avoid mistaken activation or inactivation of a protection function at the time of re-lighting of the light source due to the influence of the residual heat after the light source is turned off.