Surface Emitting Laser Array Polarization Control
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Solution Overview
Problem
Existing surface emitting laser arrays face challenges in maintaining uniform polarization directions of light beams without reducing the integration density of light emitting units, leading to uneven color distribution in images formed by devices like laser printers.
Innovation Solution
The surface emitting laser array is designed with light emitting units having anisotropic internal stress, where the distance between each unit's center and the wiring member is carefully adjusted to maintain polarization direction variations within a predetermined range, allowing for uniform polarization without decreasing the integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the density of light emitting units is increased to maintain high integration, then the polarization direction variations increase, but uniform polarization direction is required for consistent light intensity
Solution Approach 1:
The patent applies local quality by introducing anisotropic internal stress specifically in the wiring members connected to light emitting units. The stress characteristics are locally adjusted based on the orientation of the wiring member relative to the crystal axis, creating different stress effects for different units while maintaining overall high density arrangement
Solution Approach 2:
The patent changes physical parameters by controlling the stress characteristics of wiring members. By adjusting the stress magnitude and direction in different wiring members, the polarization directions of emitted light beams are controlled to remain uniform across all light emitting units, even when arranged at high density
2Ease of manufacture
If wiring members are arranged to connect light emitting units, then electrical connection is established, but the wiring members induce stress that changes polarization directions
Solution Approach 1:
The patent converts the harmful stress effect induced by wiring members into a beneficial control mechanism. By intentionally designing the wiring members to have controlled anisotropic internal stress, the stress that would normally disrupt polarization uniformity is instead used to actively control and maintain uniform polarization directions across all light emitting units
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 approach effectively reduces variations in polarization directions of light beams emitted from the surface emitting laser array, ensuring consistent color distribution and image quality in applications like color printers without compromising the density of light emitting units.
Implementation Method 1
The light emitting unit has anisotropic internal stress; and when viewed from a direction orthogonal to the substrate, a first distance between the center of a first light emitting unit of the light emitting units and the center line of the wiring member connected to the first light emitting unit is arranged to be different from a second distance between the center of a second light emitting unit of the light emitting units and the center line of the wiring member connected to the second light emitting unit
Data Source
AI summary
A surface emitting laser array includes a light emitting unit having a lower reflection mirror, a resonator structure including an active layer, and an upper reflection mirror laminated on a substrate; an electrode for the light emitting unit; a wiring member that establishes electrical connection between the light emitting unit and the electrode; and the substrate on which more than one of the light emitting units, the electrodes, and the wiring members are arranged. The light emitting unit has anisotropic internal stress, and the distance between the center of a first light emitting unit and the center line of the corresponding wiring member is arranged to be different from the distance between the center of a second light emitting unit and the center line of the corresponding wiring member so that variations in the polarization directions of the light emitting units may be within a predetermined range.