Integrated Laser Modulator for Precise Pixel Brightness Control
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Solution Overview
Problem
Laser scanning micro-electro-mechanical systems (MEMS) displays face challenges in accurately controlling pixel brightness due to non-linear optical power response to laser injection current, especially near the threshold current, leading to reduced brightness accuracy and perceived image quality.
Innovation Solution
Integration of a modulator with the gain section of the laser device allows for precise control of pixel brightness by amplifying or attenuating the optical power, effectively moving away from the problematic operating region near the threshold current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If laser injection current is used to control pixel brightness, then the display can operate with simple control, but brightness accuracy deteriorates near the threshold current due to non-linear optical power response
Solution Approach 1:
An integrated modulator is introduced as an intermediary component between the laser gain section and the display. The modulator receives light from the gain section and applies additional modulation to achieve precise brightness control. This mediator allows the system to maintain simple current control for the gain section while adding precision through the modulator's optical modulation capability, thereby resolving the contradiction between operational simplicity and brightness accuracy.
2Use of energy by moving object
If the laser operates near the threshold current to achieve low brightness levels, then power consumption is reduced, but brightness accuracy deteriorates due to threshold current shifts
Solution Approach 1:
The integrated modulator serves as a mediator that enables precise brightness control at low power consumption levels. By operating the gain section at a stable bias point away from the threshold and using the modulator to achieve the desired low brightness levels, the system avoids threshold current shifts while maintaining low power consumption and high brightness accuracy simultaneously.
Solution Approach 2:
The gain section is preliminarily biased at a stable operating point above the threshold current, establishing a stable baseline optical power. The modulator then applies preliminary attenuation to achieve the final low brightness levels. This preliminary action at a stable bias point prevents threshold current shift problems while enabling low power consumption operation.
3Device complexity
If a single gain section is used to cover the full brightness range, then device complexity is minimized, but brightness control precision deteriorates across the dynamic range
Solution Approach 1:
The modulator is integrated with the gain section to form a compound light source system. The gain section provides the fundamental laser output with good stability, while the integrated modulator extends the dynamic range and improves brightness control precision. This intermediary component enables the system to maintain low complexity while achieving high precision across the full brightness range.
Solution Approach 2:
The modulator and gain section are merged into an integrated laser device structure. This combining allows the two components to work together as a unified system, where the gain section handles the bulk of the light generation and the modulator provides fine-tuned brightness control. The integration minimizes the increase in device complexity while maximizing brightness control precision across the dynamic range.
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 solution enables accurate pixel brightness control, reducing errors and improving image quality by extending the dynamic range of the laser device and minimizing the impact of threshold current shifts.
Implementation Method 1
The gain section is configured to selectively amplify an optical power of light reflecting within the gain section based on a first drive current or voltage supplied from the first current or voltage source to the gain section
Implementation Method 2
The modulator is configured to selectively attenuate or amplify an optical power of light received from the gain section based on a second drive current or voltage supplied from the second current or voltage source to the modulator
Data Source
AI summary
A laser device for use with a display including a plurality of pixels is disclosed. The laser device includes a gain section and a modulator. The gain section is electrically coupled with a first current or voltage source. The gain section is configured to selectively amplify an optical power of light reflecting within the gain section based on a first drive current or voltage supplied from the first current or voltage source to the gain section. The modulator is optically coupled with the gain section. The modulator is electrically coupled with a second current or voltage source. The modulator is configured to selectively attenuate or amplify an optical power of light received from the gain section based on a second drive current or voltage supplied from the second current or voltage source to the modulator. Light emitted from the modulator is provided to the display.