LED Illuminator Temperature Feedback Control
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Solution Overview
Problem
LED illuminators used in measurement devices face fluctuations in brightness due to heat generation, causing unstable illuminance as the forward voltage changes, leading to fluctuations in the forward current.
Innovation Solution
Incorporating a temperature sensor and an illumination controller that adjusts the drive voltage based on the current temperature of the light emitter to maintain a constant forward current and brightness, thereby stabilizing illuminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a constant voltage control circuit is used to maintain LED brightness, then the voltage applied to the LED is stabilized, but the forward voltage fluctuates due to heat generation causing brightness fluctuation
Solution Approach 1:
The patent implements a feedback control mechanism where a temperature sensor continuously monitors the LED temperature and feeds this information back to the control unit. The control unit then adjusts the drive voltage accordingly to compensate for temperature-induced forward voltage changes, thereby maintaining stable brightness despite thermal effects
Solution Approach 2:
The patent changes the control parameter from fixed voltage to temperature-compensated voltage. By monitoring temperature and dynamically adjusting the drive voltage based on temperature readings, the system compensates for the changing forward voltage characteristics of the LED, resolving the contradiction between voltage stability and brightness stability
2Stability of the object's composition
If the drive voltage is reduced to compensate for forward voltage lowering due to temperature rise, then the forward current can be stabilized, but the brightness may decrease
Solution Approach 1:
The temperature feedback mechanism allows the system to precisely calculate the required voltage adjustment based on actual temperature readings. This ensures that the drive voltage is reduced only by the exact amount needed to compensate for forward voltage changes, maintaining optimal brightness while stabilizing current
Solution Approach 2:
The system transitions from a static fixed-voltage approach to a dynamic temperature-compensated voltage approach. The drive voltage is continuously adjusted based on real-time temperature conditions, allowing the system to adapt to changing thermal states while maintaining both current stability and optimal brightness
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 effectively stabilizes the brightness of the LED by adjusting the drive voltage in response to temperature changes, ensuring consistent illuminance with a simplified configuration and reduced processing load.
Implementation Method 1
a temperature sensor configured to detect a current temperature of the light emitter
Implementation Method 2
an illumination controller configured to adjust a drive voltage being supplied to the light emitter in accordance with the current temperature
Implementation Method 3
a light emitter including a light-emitting diode
Implementation Method 4
In causing the light-emitting diode (LED) to emit light
Data Source
AI summary
An illuminator includes: a light emitter including a light-emitting diode; a temperature sensor configured to detect a current temperature of the light emitter; and an illumination controller configured to adjust a drive voltage being supplied to the light emitter in accordance with the current temperature. The illumination controller includes a reference temperature storage in which a reference temperature is stored in advance and is configured to adjust the drive voltage by detecting the current temperature from the temperature sensor on a constant time cycle and comparing the current temperature with the reference temperature.