Laser Package Cap Layout for Stray Light Blocking and Marking
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Solution Overview
Problem
Existing light emitting devices with light-transmissive cover glasses suffer from stray light extraction and lack a mechanism for printing information such as lot numbers, making them less compact and inefficient.
Innovation Solution
A light emitting device design featuring a package with a metal film, a cap with a light-transmissive member and a light blocking film on its lower surface, and a joining member that reduces stray light by positioning the light blocking film to block stray light and create a mark formation region, allowing for a more compact device with reduced stray light and the ability to print information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the cover glass is entirely light-transmissive, then light transmission is maximized, but stray light is extracted from the cover glass
Solution Approach 1:
The light blocking film is applied selectively to specific regions of the cover glass surface, creating local variations in light transmission properties. The film blocks light in certain areas while leaving other areas transparent, thus reducing stray light without completely compromising overall light transmission.
Solution Approach 2:
The light blocking film serves as an intermediary layer between the light source and the external environment. It mediates the light transmission by selectively blocking certain light paths while allowing others to pass through, thus controlling stray light extraction.
2Device complexity
If no mark formation region is provided, then the device structure is simpler, but information such as lot numbers cannot be printed
Solution Approach 1:
The light blocking film serves multiple functions: it blocks stray light and simultaneously provides a mark formation region for printing information. This multi-functionality resolves the contradiction by adding information printing capability without significantly increasing structural complexity.
3Reliability
If the light blocking film is positioned away from the laser element, then the laser element is better protected, but stray light is not effectively blocked
Solution Approach 1:
The light blocking film is positioned strategically at specific locations where stray light tends to extract, rather than uniformly surrounding the laser element. This localized positioning effectively blocks stray light paths while maintaining adequate protection of the laser element.
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 effectively reduces stray light and enables the printing of information, resulting in a more compact and efficient light emitting device with improved light management and marking capabilities.
Implementation Method 1
a light blocking film arranged on the lower surface of the light-transmissive member and having a shape defining at least one opening
Data Source
AI summary
A light emitting device includes a package, a cap, a joining member and at least one laser element. The package includes a metal film. The cap includes a light-transmissive member having a lower surface facing the package and an upper surface opposite to the lower surface, and a light blocking film arranged on the lower surface of the light-transmissive member and having a shape defining at least one opening. The joining member joins a part of the light blocking film and the metal film. The at least one laser element is positioned in a space bounded by the cap and the package such that a part of an edge of the at least one opening defined by the light blocking film is disposed directly above the at least one laser element.