HID Lamp Envelope Temperature Stabilization via Thermoelectric Cooling
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Solution Overview
Problem
High Intensity Discharge (HID) lamps in automated luminaires face instability in maintaining target color temperature due to variations in arc gap and envelope temperature, with existing cooling systems being ineffective and slow to operate, leading to noticeable changes in output color temperature.
Innovation Solution
A tightly temperature-controlled enclosure for the HID lamp, utilizing controllable fans and temperature sensors connected to a central controller, operates as a parameterized closed-loop system to maintain envelope temperature within close tolerances, ensuring stable color temperature output by dynamically adjusting fan speeds based on power changes and operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fan cooling systems are used to stabilize lamp temperature, then cooling capability is provided, but the response is slow and color temperature stability is insufficient
Solution Approach 1:
The patent replaces the mechanical fan cooling system with a thermoelectric cooler (TEC) system that uses electrical current to directly heat or cool the lamp envelope. This substitution of mechanical cooling with solid-state thermoelectric cooling enables rapid response times and precise temperature control, resolving the contradiction between cooling capability and response speed.
Solution Approach 2:
The patent changes the control parameter from simple on/off fan operation to continuous adjustable electrical current through the TEC. By varying the current magnitude and direction, the system can precisely control the heating or cooling rate, achieving fast response and stable temperature control simultaneously.
2Illumination intensity
If power consumption is changed to control brightness, then intensity control is achieved, but color temperature stability deteriorates
Solution Approach 1:
The patent implements a feedback control system where temperature sensors continuously monitor the lamp envelope temperature and feed this information to a controller. The controller adjusts the TEC current in real-time to compensate for temperature changes caused by power variations, allowing brightness control without sacrificing color temperature stability.
Solution Approach 2:
The TEC system acts as an intermediary between the power input and the lamp envelope temperature. It decouples the relationship between power consumption and temperature by actively compensating for thermal changes, enabling independent control of brightness and color temperature.
3Duration of action of stationary object
If arc gap varies as electrodes burn away, then lamp operation continues, but color temperature precision deteriorates
Solution Approach 1:
The feedback control system continuously monitors temperature and adjusts TEC current to compensate for drift caused by arc gap variations. This maintains color temperature precision throughout the lamp's operational life, counteracting the degradation that would otherwise occur as electrodes burn away.
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 provides continuous and dynamic control of the lamp envelope temperature, stabilizing the output color temperature and minimizing noticeable changes, even during power adjustments or blackout periods, resulting in a consistent and stable light output.
Implementation Method 1
a thermoelectric cooler having a first side in thermal communication with the lamp envelope and a second side in thermal communication with the heat sink
Implementation Method 2
temperature sensors configured to read the temperature of the lamp envelope
Implementation Method 3
controllable fans and temperature sensors connected to a central controller
Data Source
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AI summary
Described is dynamic control of the temperature of the envelope of an HID lamp (30) in order to stabilize the output color temperature of the lamp. As the lamp power is changed, or environmental factors alter the lamp envelope temperature, the system senses these changes and adjusts the lamp cooling systems (42a, 42b) so as to move the lamp envelope temperature back to the desired point.