Laser Source Module Thermal Decentering for Optical Axis Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser projectors face issues with optical axis misalignment and thermal deformation, leading to blurred images due to relative displacements of laser spots on the screen, especially when emission points of lasers are displaced due to temperature rise.
Innovation Solution
A laser source module is configured such that laser beams from multiple sources are decentered in the same direction on the combined beam optical axis, using mirrors that reflect or transmit beams based on wavelength and polarization, and positioning the laser chip and heat sink reversely relative to the beam emission direction to align decentering directions of optical axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If laser sources are used in a scanning image display device, then the device can be made compact and portable, but thermal deformation causes optical axis misalignment and blurred images
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning the laser chips at locations that anticipate thermal deformation. The laser chips are arranged so that when thermal expansion occurs, their emission points shift in a controlled manner that maintains optical axis alignment. This proactive positioning counteracts the expected thermal deformation rather than attempting to correct it after the fact.
Solution Approach 2:
The patent changes the physical parameters of the laser source assembly by positioning laser chips at specific locations relative to the heat sink geometry. The arrangement accounts for differential thermal expansion coefficients between materials, positioning chips so that thermal deformation produces beneficial alignment rather than misalignment. This parameter optimization allows the system to maintain reliability under thermal stress.
2Adaptability or versatility
If multiple laser sources are combined, then color image display is enabled, but alignment of optical axes becomes difficult and complex
Solution Approach 1:
The patent applies asymmetry by positioning laser chips at non-symmetric locations relative to the heat sink. Rather than arranging all laser chips identically, the design uses asymmetric positioning that compensates for thermal deformation patterns. This asymmetric arrangement simplifies the overall alignment process by pre-compensating for expected shifts, reducing the complexity of achieving and maintaining optical axis alignment across multiple color lasers.
3Temperature
If laser chips are mounted on heat sinks, then thermal management is improved, but emission points displace due to thermal expansion mismatch
Solution Approach 1:
The patent applies preliminary action by pre-positioning laser chips on the heat sink at locations that anticipate thermal expansion. During the manufacturing process, chips are mounted at specific coordinates that account for the expected displacement due to thermal cycling. This preliminary positioning ensures that even as the heat sink expands and contracts with temperature changes, the laser emission points remain aligned with the optical axis.
Solution Approach 2:
The patent directly addresses thermal expansion by designing the laser chip positioning to accommodate differential expansion between the laser chip materials and the heat sink material. The chip locations are calculated based on the known thermal expansion coefficients of the materials, positioning chips so that their displacement due to thermal expansion maintains optimal optical alignment rather than degrading it.
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 ensures that even with thermal deformation, the decentering directions of optical axes coincide, significantly reducing relative displacements of laser spots on the screen, resulting in a clearer image.
Implementation Method 1
the beams are reflected by their respective beam combining mirrors and combined into a combined beam
Implementation Method 2
a plane on which main beam light paths including the combined beam optical axis are formed is assumed to be a light path plane
Implementation Method 3
the base and heat sink have different coefficients of thermal expansion or the laser chip, sub-mount, and heat sink have different coefficients of thermal expansion, thus causing uneven thermal deformations of these elements
Implementation Method 4
a cylindrical metal package product called a CAN package prevails. This product has a structure in which a half-cylindrical heat sink is coupled onto the front face of a cylindrical base
Implementation Method 5
each including a laser having a laser chip installed on a heat sink
Data Source
AI summary
In a laser source module aligning laser beams from laser sources for three colors, red, green, and blue on a single combined beam optical axis, decreasing relative displacements of beam spots of three colors, occurring due to thermal deformation by temperature rise, is achieved by a laser source module including plural laser sources, each incorporating a laser having a laser chip installed on a heat sink and a lens converting a light radiated from the laser into a laser beam, and a beam combining unit aligning the laser beams from the laser sources on a single combined beam optical axis, wherein the lasers in at least two or more ones of the laser sources are arranged so that their laser beams will be decentered toward a same direction on the combined beam optical axis upon displacement of an emission point of the laser chip away from the heat sink.