Semiconductor Laser Driver Layout for Low-Inductance ToF Pulsing
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Solution Overview
Problem
The integration of laser diode arrays and driver ICs in existing optical modules results in significant wiring inductance, leading to distorted drive waveforms, particularly in high-frequency applications like ToF systems.
Innovation Solution
A semiconductor laser driving apparatus with a substrate incorporating a laser driver and semiconductor laser, connected via wiring with 0.5 nanohenries or less, utilizing optical elements to reduce inductance and enhance irradiation, including collimator lenses and diffractive elements for spot or uniform irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser diode array and driver IC are integrated as separate components in an optical module, then ease of manufacture is improved, but wiring inductance increases causing drive waveform distortion
Solution Approach 1:
The patent merges the laser diode array and driver IC into a single integrated chip structure, eliminating separate components and their connecting wires. This integration directly reduces wiring inductance while maintaining manufacturing feasibility through advanced semiconductor fabrication processes.
Solution Approach 2:
The patent transitions from a planar wiring layout to a three-dimensional vertical structure where the laser diode array and driver IC are stacked vertically on the same chip. This dimensional change enables extremely short connection paths between components, dramatically reducing inductance while preserving ease of manufacture.
2Ease of manufacture
If multiple wires are used to connect laser diode array and driver IC, then ease of manufacture is improved, but wiring inductance becomes large causing signal distortion
Solution Approach 1:
The patent combines multiple wiring functions into integrated on-chip interconnects, eliminating the need for separate external wires. This merging simplifies the wiring structure while maintaining manufacturing ease through standard semiconductor fabrication techniques.
3Ease of operation
If wiring length is increased to facilitate assembly, then ease of operation is improved, but wiring inductance increases reducing irradiation power
Solution Approach 1:
The patent employs vertical stacking to achieve extremely short connection lengths without compromising assembly ease. The three-dimensional integration allows components to be connected over minimal distances in the vertical dimension, preserving irradiation power while facilitating assembly through standardized packaging processes.
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
Reduces wiring inductance to improve drive waveform stability and increase irradiation power, enhancing the performance of ToF systems by improving SN ratio and reducing distortion.
Implementation Method 1
the first optical element may be an optical element that makes the irradiation light from the semiconductor laser into parallel light
Implementation Method 2
the second optical element may be a diffractive optical element that diffracts the parallel light
Implementation Method 3
a diffusion element that refracts light having passed through the first optical element
Data Source
AI summary
To reduce the wiring inductance between a semiconductor laser and a laser driver in a semiconductor laser driving apparatus. A substrate incorporates a laser driver. A semiconductor laser is mounted on one surface of the substrate of a semiconductor laser driving apparatus to emit irradiation light from an irradiation surface. Connection wiring electrically connects the laser driver and the semiconductor laser to each other with a wiring inductance of 0.5 nanohenries or less. A first optical element is provided on the irradiation surface side of the semiconductor laser. A second optical element is provided outside the first optical element on the irradiation surface side of the semiconductor laser.