Semiconductor Laser Lens Array Layout for Rotational Tolerance
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Solution Overview
Problem
Conventional light source devices with collimator lens arrays are prone to significant deviations in the positional relationship between light sources and lens elements when the lens array is slightly rotated, leading to changes in the intensity distribution of emitted light.
Innovation Solution
A light-emitting device comprising a substrate, a lens array with a matrix pattern of lens sections, and semiconductor laser elements, where each laser beam has a wider beam shape in the column direction than in the row direction on the light incident surface of each lens section, and the lens sections have a consistent curvature in both directions and inter-vertex distances optimized to minimize positional deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If lens elements have a plurality of curvatures in accordance with sectional shapes of laser beams, then the collimation performance is improved, but the positional relationship between light sources and lens elements becomes highly sensitive to rotation, causing significant deviation and intensity distribution changes
Solution Approach 1:
The patent applies local quality by having different curvature radii in different directions (first curvature radius in the first direction, second curvature radius in the second direction) to match the anisotropic beam shape of laser diodes. This allows optimal collimation in each principal direction while the overall spherical or toroidal lens shape maintains rotational tolerance, resolving the contradiction between customized collimation and positional stability.
2Ease of operation
If the lens array is mounted slightly rotated from the prescribed direction, then assembly flexibility is improved, but significant deviation occurs in the positional relationship between light sources and lens elements
Solution Approach 1:
The patent employs asymmetry in the curvature design (different curvature radii in orthogonal directions) to create a lens that is optimized for the specific anisotropic beam shape of laser diodes. This asymmetric design, when combined with the inter-vertex distance being smaller than both curvature radii, creates a tolerance zone that allows slight rotational misalignment without causing significant positional deviation, thus enabling assembly flexibility while maintaining manufacturing precision.
3Reliability
If the inter-vertex distance is reduced to minimize positional deviations, then the sensitivity to rotation is reduced, but the lens section size and optical path may be constrained
Solution Approach 1:
The patent utilizes parameter changes by establishing specific relationships between the inter-vertex distance and the curvature radii (inter-vertex distance smaller than both first and second curvature radii). By optimizing these geometric parameters, the design achieves rotational tolerance and positional stability while maintaining appropriate lens section dimensions for effective optical operation, resolving the contradiction between reliability and dimensional constraints.
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 ensures that even when the lens array is mounted slightly rotated, significant deviations in the positional relationship between light sources and lens elements are minimized, thereby stabilizing the intensity distribution of light emitted from the lens array.
Implementation Method 1
A light source device that collimates light emitted from a plurality of light sources with a collimator lens array
Data Source
AI summary
A light-emitting device includes: a substrate including a base and a side wall; a plurality of semiconductor laser elements arrayed in a first direction on an upper surface of the base; a sealing member fixed to the substrate, wherein the sealing member and the substrate define a sealed space in which the semiconductor laser element is located; and a lens array disposed above the sealing member, the lens array including a plurality of lens sections arrayed in the first direction. In the lens array, a maximum outer diameter of each lens sections is 1.25 times or more than an inter-vertex distance between adjacent ones of the lens sections in the first direction.