Edge-Emitting Laser Package Height Reduction via Folded Optical Path
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Solution Overview
Problem
Conventional edge-emitting laser packages have a high overall height due to a large perpendicular distance between the substrate mounting surface and the collimating lens, leading to increased volume and space occupation, which is undesirable for portable electronic devices.
Innovation Solution
The package structure incorporates two reflective members and a diffractive optical element to alter the laser beam path, maintaining the light output axis at the package center and reducing the overall height by minimizing the distance between the top surface of the housing and the mounting surface, using a configuration that includes a carrier, housing, edge-emitting laser, first and second reflective members, and a diffractive optical element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional lead-type package structure is used with a perpendicular distance greater than 9 mm between the substrate mounting surface and the collimating lens, then the laser beam can be effectively collimated, but the overall height of the package structure is increased and the volume is increased, occupying too much space
Solution Approach 1:
The patent changes the optical path from a vertical arrangement to a folded path using reflective members. The laser beam travels horizontally from the edge-emitting laser, reflects off the first reflective member at 45 degrees, then reflects off the second reflective member back towards the housing center, and finally passes through the diffractive optical element. This dimensional reconfiguration reduces the perpendicular distance from greater than 9 mm to less than 5 mm while maintaining collimation quality.
Solution Approach 2:
The patent introduces reflective members and a diffractive optical element as intermediary components to redirect and reshape the laser beam path. These intermediaries enable the beam to achieve collimation without requiring a long perpendicular distance, as the reflective members fold the optical path and the diffractive optical element provides the necessary beam shaping in a compact configuration.
2Length of stationary object
If the perpendicular distance between the substrate mounting surface and the collimating lens is reduced to decrease package height, then the volume is reduced, but maintaining proper optical alignment and collimation becomes more difficult
Solution Approach 1:
By folding the optical path using reflective members positioned at specific angles (45 degrees), the patent achieves effective optical path length extension within a reduced perpendicular footprint. This dimensional change allows the beam to traverse a longer effective path for collimation while maintaining a compact package height of less than 5 mm, thereby preserving alignment precision without requiring increased vertical space.
Solution Approach 2:
The patent segments the optical path into distinct sections handled by different components: the edge-emitting laser generates the beam, the first reflective member redirects it horizontally, the second reflective member redirects it back toward the housing center, and the diffractive optical element performs final beam shaping. This segmentation allows each component to be optimized for its specific function, maintaining overall optical precision in a compact configuration.
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 configuration significantly decreases the overall height of the package structure to less than 5 mm, reducing volume and enabling better optical path alignment, thus enhancing suitability for portable devices and reducing adjustment time.
Implementation Method 1
The first reflective member is received in the receiving space, and spaced apart from the light-emitting surface. The second reflective member is received in the receiving space, and located on a center line above the edge-emitting laser. The laser beam is reflected by the first reflective member and the second reflective member
Implementation Method 2
The diffractive optical element is disposed on a top surface of the housing. The laser beam is reflected by the first reflective member and the second reflective member, and then passes through the diffractive optical element to emit out of the housing
Data Source
AI summary
A package structure includes a carrier, a housing, an edge-emitting laser, first and second reflective members and a diffractive optical element. The housing disposed on a mounting surface of the carrier has a receiving space and a top surface, which has an opening and a center line perpendicular to the top surface and the mounting surface. The edge-emitting laser disposed in the receiving space and on the mounting surface has a light-emitting surface emitting a laser beam. The first reflective member is disposed in the receiving space and spaced apart from the light-emitting surface. The second reflective member is disposed in the receiving space and located on the center line above the edge-emitting laser. The diffractive optical element is disposed on the top surface. The laser beam reflected by the first and second reflective members passes through the diffractive optical element to emit out of the housing.