Solid-State Auxiliary Lamp for Accurate SSL Photometric Testing
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Solution Overview
Problem
Conventional photometric test systems face challenges in accurately measuring large-scale SSLs due to issues like self-absorption errors, heat management, and inefficiencies in optical measurement, particularly when using incandescent auxiliary lamps which require long warm-up times and generate heat, leading to measurement uncertainties and increased costs.
Innovation Solution
A Solid-State Auxiliary Lamp (SSAL) system utilizing LEDs with a multichannel current source and thermoelectric cooling, designed to provide stable, broadband radiation with minimal warm-up time, and capable of precise temperature control, which reduces self-absorption errors and enhances measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an integrating sphere is used for photometric testing of SSLs, then optical measurements can be obtained, but self-absorption errors occur when the DUT physical characteristics differ significantly from the reference standard
Solution Approach 1:
The patent introduces a spherical auxiliary lamp as an intermediary device that remains mounted in the integrating sphere throughout measurements. This auxiliary lamp serves as a mediator to characterize and correct self-absorption errors by providing a stable reference that accounts for changes in sphere system responsivity when different DUTs are tested, thereby resolving the contradiction between obtaining optical measurements and avoiding self-absorption errors
2Illumination intensity
If conventional incandescent auxiliary lamps are used, then broadband radiation can be provided, but long warm-up times and heat generation occur leading to measurement uncertainties
Solution Approach 1:
The patent changes the fundamental parameter of the auxiliary lamp from incandescent to solid-state LED technology. This parameter change enables the auxiliary lamp to provide broadband radiation through multiple LED chips with different spectral distributions while eliminating the long warm-up time and excessive heat generation associated with incandescent lamps, as LEDs reach operational stability immediately and generate significantly less heat
3Productivity
If high powered LEDs are mounted on reliability test boards with multiple LEDs, then large scale SSL testing can be performed, but the wiring and large circuit board absorb significant portions of LED light degrading optical measurement
Solution Approach 1:
The patent extracts the auxiliary lamp function from the traditional incandescent bulb form and implements it using solid-state LED technology mounted on a minimized substrate. This extraction allows the auxiliary lamp to provide necessary broadband radiation while occupying minimal space and absorbing minimal light, thereby maintaining high productivity for large-scale SSL testing while preserving optical measurement precision
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 SSAL system achieves repeatable and accurate optical measurements with reduced warm-up time, improved heat management, and increased stability, thereby enhancing the reliability and efficiency of large-scale SSL testing while reducing costs and measurement uncertainties.
Implementation Method 1
The LEDs are mounted on a heat sink with a thermoelectric cooler that maintains the SSAL at a predefined temperature
Implementation Method 2
A Solid-State Auxiliary Lamp (SSAL) system utilizing LEDs with a multichannel current source and thermoelectric cooling, designed to provide stable, broadband radiation
Data Source
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Figure 5
AI summary
A solid-state auxiliary lamp Includes a lamp head having a plurality of LED modules; 3 thermoelectric cooler coupled to the LED modules; and a drive unit. The drive unit can include a plurality of current sources., each of the current sources coupled to a corresponding LED module.; and a processor coupled to the current sources and configured to control each current source to control the light output of each current source's corresponding LED module.