Laser Pulse Generator Temperature Compensation for Stable Pulse Shape
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Solution Overview
Problem
Laser pulse generators used in distance sensors experience temperature-dependent pulse shape changes due to semiconductor component behavior, leading to inaccurate distance measurements and reduced range over time.
Innovation Solution
A laser pulse generator with a temperature sensor connected to the pulse width and delay generators, which adjusts the charging and delay times to compensate for temperature-induced resistance changes in the avalanche transistor, maintaining a stable pulse shape across the operating temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional laser pulse generator with semiconductor components is used, then the device can operate over a wide temperature range, but the pulse shape changes due to temperature-dependent resistance changes in the avalanche transistor and laser diode
Solution Approach 1:
The patent applies preliminary action by pre-charging the pump capacitor to a temperature-compensated voltage level before the laser pulse is generated. The control device determines the ambient temperature and sets the pump capacitor voltage accordingly before discharge, compensating for expected resistance changes in the avalanche transistor and laser diode. This ensures stable pulse shapes across temperature ranges without requiring active feedback during pulse generation.
Solution Approach 2:
The patent changes the electrical parameter (pump capacitor voltage) based on temperature conditions. The control device adjusts the charging voltage of the pump capacitor as a function of the determined ambient temperature, thereby compensating for temperature-dependent resistance changes in the discharge circuit components and maintaining stable laser pulse characteristics.
2Use of energy by moving object
If the pump voltage is increased to maximize laser pulse energy and measurement range, then the measurement range is extended, but the pulse shape becomes more sensitive to temperature-dependent resistance changes
Solution Approach 1:
The patent optimizes the pump capacitor voltage parameter based on temperature conditions to achieve the best compromise between pulse energy and shape stability. By adjusting this parameter, the system maintains stable pulse shapes even at high energy levels, ensuring accurate distance measurements while maximizing measurement range.
3Measurement precision
If temperature compensation circuitry is added to stabilize pulse shapes, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback by using a temperature sensor to continuously monitor ambient temperature and feeding this information to the control device. The control device then adjusts the pump capacitor charging voltage based on the temperature feedback, creating a closed-loop system that automatically compensates for temperature effects without complex additional circuitry.
Solution Approach 2:
The system performs self-service by automatically adjusting its own operating parameters (pump capacitor voltage) based on temperature conditions. The control device autonomously determines the optimal voltage level without requiring external intervention or complex manual calibration, simplifying the overall system architecture.
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 solution stabilizes the laser pulse shape, enhancing distance measurement accuracy and extending the measurement range by compensating for temperature fluctuations and component aging.
Implementation Method 1
a temperature sensor TS, which is connected to the pulse width generator GB and detects a temperature
Implementation Method 2
an inductive component B and, connected to a voltage source V, forms a first charging circuit in which, while the switch S is closed in a charging time tL, the inductive component B is inductively charged
Implementation Method 3
an ignition pulse Pt is applied to a base of the avalanche transistor Taval, which is connected to the delay generator GV, so that the avalanche transistor Taval is switched on
Implementation Method 4
a pump capacitor K, which, after the switch S has opened, forms a discharge circuit with the avalanche transistor Taval and the laser diode LD
Implementation Method 5
The discharge circuit closes. The pump capacitor K discharges via the avalanche transistor Taval, which is switched to low resistance, and the laser diode LD
Data Source
Figure 1
AI summary
A laser pulse generator with a stable pulse shape, comprising a mono-pulse high-voltage generator (GH), a pulse current generator (GI), a pulse width generator (GB), and a delay generator (GV). The pulse current generator (GI) includes a discharge circuit formed by a pump capacitor (K), an avalanche transistor (Taval), and a laser diode (LD). To compensate for the influence of the temperature-dependent resistance of the avalanche transistor (Taval) on the discharge current pulse (IE) that excites the laser diode (LD), a temperature sensor (TS) is provided. This sensor detects the transistor's temperature and generates a temperature signal (Ptemp), which indirectly influences the pump voltage (UC) of the pump capacitor (K).