Dynamic Laser Diode Bias Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser diodes in display applications face challenges with high power usage and temperature-dependent voltage-current characteristics, leading to inaccurate and slow temperature compensation, which affects energy efficiency and color accuracy.
Innovation Solution
A system that dynamically adjusts the bias voltage of laser diodes using a voltage sensor and controller, estimating junction temperature based on measured voltage and current, and adjusting the supply voltage to manage power usage and prevent saturation, while also compensating for temperature fluctuations and anticipating video data activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the bias voltage of the laser diode is reduced to lower power usage, then energy consumption decreases, but the laser diode is more likely to saturate while outputting a display signal
Solution Approach 1:
The patent implements dynamic bias voltage adjustment by continuously monitoring the actual voltage across the laser diode and comparing it to a target voltage. The bias voltage is automatically adjusted in real-time to maintain the desired voltage level, allowing the system to operate at lower power while preventing saturation through active control rather than static voltage setting
Solution Approach 2:
The system employs a feedback mechanism where the actual voltage across the laser diode is measured and fed back to a controller. The controller compares the measured voltage with the target voltage and adjusts the bias voltage accordingly. This closed-loop control enables the system to maintain optimal operating conditions while using lower power, resolving the contradiction between power reduction and saturation prevention
2Temperature
If conventional temperature compensation methods are used to adjust bias voltage, then temperature effects are partially compensated, but the compensation is inaccurate and slow
Solution Approach 1:
The patent replaces conventional temperature sensing methods (such as thermistors or thermal sensors) with an electrical measurement approach. By measuring the actual voltage across the laser diode and using this electrical parameter to infer temperature effects, the system achieves more accurate and faster temperature compensation without relying on thermal sensors that are inherently slow and imprecise
Solution Approach 2:
The system uses the voltage measurement across the laser diode as an intermediary parameter to indirectly determine temperature effects. Instead of directly measuring temperature with slow thermal sensors, the voltage measurement serves as a faster intermediary that correlates with temperature, enabling more responsive and accurate temperature compensation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system for dynamically adjusting a bias voltage for a laser diode (430) or a light emitting diode is provided. An output voltage of the laser diode is measured and a level of a supply voltage (V-) applied to the laser diode (430) is adjusted to change the bias voltage of the laser diode (430) to manage power usage and avoid saturation of the laser diode (430). Also, a junction temperature of a laser diode (430) may be estimated by mapping a measured output voltage at a known current to device characteristic data (443) based on temperature and adjusting the supply voltage (V-) in order to bias the laser diode (430) to compensate for a temperature change. Further, data (442) indicating an intensity level of data to be rendered by the laser diode is used to adjust the supply voltage (V-) to bias the laser diode in advance of rendering the data.