Sheet-Probe Burn-In Testing for Laser Diode Bars
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Solution Overview
Problem
Conventional burn-in testing methods for laser diodes in a bar state are inefficient due to the high cost and mechanical stress caused by metallic probes, and the difficulty in maintaining stable contact due to variations in laser diode thickness, which leads to reduced yield rates and increased assessment time.
Innovation Solution
A method involving sheet-shaped probes that contact the second electrode and pad at a slantwise angle, with the second pad positioned on the dicing margin, allowing for flexible pad size and reduced mechanical stress, enabling stable electrical contact and efficient testing of multiple laser diodes in a bar state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic probes are used for burn-in testing, then electrical contact can be established, but high cost and mechanical stress are caused
Solution Approach 1:
The patent replaces expensive metallic probes with inexpensive sheet-shaped probes that can be easily replaced. The sheet-shaped probe is made from flexible printed circuit board material which is much cheaper than metallic probes, allowing cost-effective burn-in testing while maintaining electrical contact functionality.
Solution Approach 2:
The patent replaces the mechanical metallic probe contact system with a sheet-shaped flexible printed circuit board that establishes electrical contact through a different mechanical approach. The flexible PCB can conform to the laser diode surface and maintain stable contact without the high mechanical stress of rigid metallic probes.
2Reliability
If metallic probes are used for burn-in testing, then electrical contact can be established, but mechanical stress is caused to the laser diode
Solution Approach 1:
The sheet-shaped flexible PCB probe replaces rigid metallic probes, creating a more compliant contact mechanism that distributes mechanical stress over a larger area and reduces peak stress on the laser diode while maintaining electrical contact stability.
Solution Approach 2:
The patent uses a flexible printed circuit board as the sheet-shaped probe, which provides flexibility to conform to the laser diode surface. This flexible structure reduces mechanical stress concentration compared to rigid metallic probes while maintaining reliable electrical contact during burn-in testing.
3Measurement precision
If conventional testing methods are used, then individual laser diodes can be tested, but assessment time increases for large numbers of diodes
Solution Approach 1:
The patent merges multiple laser diode testing capabilities into a single sheet-shaped flexible PCB probe structure that can contact and test multiple diodes simultaneously. The bar structure with multiple mounting areas allows parallel testing, dramatically increasing productivity while maintaining individual measurement precision through separate electrical contact paths for each diode.
Solution Approach 2:
The sheet-shaped flexible PCB probe serves multiple functions: it provides electrical contact for burn-in testing, mechanical support for the laser diodes in bar state, and simultaneous testing capability for multiple diodes. This multi-functional design increases assessment speed without sacrificing testing accuracy.
4Measurement precision
If laser diodes are tested in individual state, then thorough assessment can be performed, but time and cost increase
Solution Approach 1:
The patent combines multiple individual laser diode testing operations into a single integrated burn-in test setup. The bar structure holds multiple diodes in sequence, and the sheet-shaped probe contacts each diode simultaneously or in rapid succession, performing thorough individual assessment much faster than sequential individual testing.
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 approach allows for simultaneous and stable assessment of a large number of laser diodes, reducing assessment time and cost while maintaining reliable electrical contact, even with varying diode thicknesses, thereby improving the yield rate and economic viability of thermally-assisted heads.
Implementation Method 1
a laser diode that includes a first electrode and a second electrode formed on surfaces facing each other... providing a potential difference between the first electrode and the second electrode through the probes so that the laser diode emits laser light
Data Source
AI summary
A plurality of laser diode units is tested in a bar state, each of the laser diode units in which a laser diode that includes a first electrode and a second electrode formed on surfaces facing each other and that is mounted on a mounting surface of a submount such that the first electrode faces the mounting surface of the submount. The method includes preparing a bar in which mounting areas each of which includes the laser diode unit formed thereon and dicing margins for separating the bar into the separate laser diode units are alternatively aligned along a longitudinal direction wherein a first pad electrically connected with the first electrode of the laser diode is disposed on the mounting surface of each of the mounting areas of the submounts and a second pad electrically connected to the first pad of either one of the mounting areas that are adjacent to the dicing margin is disposed on the mounting surface of each of the dicing margins of the submounts: contacting sheet-shaped probes to the second electrode and the second pad at a slantwise angle with respect to the second electrode and the second pad, and pressing the probes to the second electrode and the second pad while deforming the probes; and providing a potential difference between the second electrode and the second pad through the probes so that the laser diode emits laser light.