LiDAR Light Module Layout for Low-Parasitic High-Current Pulses

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Solution Overview

Problem

Existing LiDAR technologies face challenges with mechanical mirrors for beam deflection, complex circuit designs, high parasitic inductances and capacitances, and inefficient energy transfer in laser diode arrays, limiting the generation of high-energy light pulses.

Innovation Solution

A compact light module design with integrated circuits on a carrier, utilizing a power transistor, laser diode, and charge storage component, optimized for minimal parasitic impedances, enabling high-current pulses through efficient energy transfer and sequential charging of multiple LEDs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mechanical mirrors are used to deflect light beams in different directions, then beam deflection is achieved, but device complexity and mechanical component requirements increase

Engineering Contradiction:
Improvebeam deflection capabilityVSAvoidmechanical components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical mirrors with an electronic beam steering mechanism using a photonic integrated circuit. The light beam is deflected by modulating the refractive index of waveguide sections through electro-optic or thermo-optic effects, eliminating moving mechanical parts while achieving the same beam direction control functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If complex circuit designs are used to control laser diode arrays, then control functionality is achieved, but parasitic inductances and capacitances increase

Engineering Contradiction:
Improvecontrol functionalityVSAvoidparasitic inductances and capacitances
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent integrates the control circuitry directly onto the photonic integrated circuit substrate, merging the electronic control functions with the optical circuit. This co-integration minimizes the length of interconnect traces, thereby reducing parasitic inductances and capacitances while maintaining full control functionality over the laser diode array.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a specialized driver circuit as an intermediary between the control logic and the laser diode array. This driver circuit is optimized with low-parasitic design techniques, including ground plane optimization and short trace routing, to minimize harmful parasitic effects while enabling precise control of the laser diodes.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If conventional energy transfer methods are used in laser diode arrays, then energy delivery is achieved, but energy transfer efficiency is limited

Engineering Contradiction:
Improveenergy deliveryVSAvoidenergy transfer efficiency
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent replaces conventional electrical energy transfer through long traces and bond wires with on-chip integrated energy delivery. The energy is transferred directly through short, low-inductance connections within the photonic integrated circuit, and the laser diodes are efficiently coupled to the waveguides, minimizing energy loss and improving overall energy transfer efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 design minimizes parasitic inductances and capacitances, allowing for rapid, high-energy light pulses without mechanical components, enhancing LiDAR performance.

Implementation Method 1

a light-emitting diode die, in particular a light-emitting diode die, having a laser diode

Methodology Applied
Scientific EffectLight-emitting diode effect: Light Emitting Diode

Implementation Method 2

at least a first bond wire which electrically connects the second terminal block of the LED die to the second terminal block of the charge storage component

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4088136B1Light module and lidar apparatus having at least one light module of this type
Publication Date: 2026.03.11 ELMOS SEMICON AG
  • EP4088136B1 patent drawingFigure 1
  • EP4088136B1 patent drawingFigure 2
  • EP4088136B1 patent drawingFigure 3

AI summary

The light module has a carrier (TR) with a circuit die, wherein, on the top side (TRO) of the carrier (TR), a light-emitting diode die (D1D) and a charge store component (LSBT) assigned to the latter are electrically connected to the conduction path connection fields (TAF1, TAF2) of a transistor (Tdis) by means of die-to-die bondings. The electrical connection between the two dies and the conduction path (LPF) of the transistor (Tdis) is as short as possible. A connection field (DAF2, LAF2) is situated in each case on the top side of the two dies, which connection fields are connected to one another using a short bonding wire (BD1). This discharge circuit is optimized with respect to the reduction of parasitic inductances and non-reactive resistances. The charge store component (LSBT) is charged by means of a charging circuit (B1) which is electrically connected to the charge store component (LSBT) via a second bonding wire (BD2). The second bonding wire (BD2) is longer than the first bonding wire (BD1). The light module may be part of a LIDAR apparatus which may have a special optical system. The driver circuit for the transistor (Tdis) may likewise be designed in a special manner.