Light Source Device Lens Positioning via Segmented Housing
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Solution Overview
Problem
Existing small-sized light source modules with semiconductor lasers face challenges in maintaining precise lens positioning due to adhesive curing shrinkage, leading to optical axis offsets, especially at high temperatures, which can result in hazy or blurry projected images and are difficult to achieve desired optical characteristics like convergence and divergence with single lenses.
Innovation Solution
A light source device with a housing that includes separate recesses for first and second lens portions, allowing for independent adjustment and fixation of each lens along specific axes, reducing the influence of adhesive curing shrinkage by using sliding and inclined surfaces to stabilize lens positions, thereby minimizing optical axis offsets and enabling desired optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a lens is fixed using adhesive after spatial adjustment in three dimensions, then the lens can be positioned precisely, but curing shrinkage of the adhesive causes the lens to move and creates optical axis offsets
Solution Approach 1:
The housing is divided into multiple functional surfaces: a first surface for fixing the first lens portion, a second surface for fixing the second lens portion, and a third surface that connects these surfaces. This segmentation allows each surface to serve a specific function in restraining lens movement while accommodating adhesive shrinkage in different directions independently.
Solution Approach 2:
Different surfaces of the housing have different geometric properties tailored to specific needs: the first surface is vertical to the optical axis for precise lateral positioning, the second surface is parallel to the optical axis for axial positioning, and the third surface provides a connecting pathway. This local optimization ensures that adhesive shrinkage in each direction does not compromise positioning in other directions.
2Reliability
If the lens is fixed with adhesive, then the lens can be secured in position, but at high temperatures the adhesive portion swells and causes optical axis offset
Solution Approach 1:
The housing structure segments the fixing function into multiple independent surfaces that can accommodate thermal expansion in different directions separately. The first surface handles lateral positioning while the second surface handles axial positioning, isolating the effects of thermal swelling.
Solution Approach 2:
The third surface connects the first and second surfaces, creating a three-dimensional fixing structure that provides additional degrees of freedom for accommodating thermal expansion. This multi-dimensional approach distributes the stress of thermal swelling across multiple directions rather than concentrating it in one plane.
3Volume of moving object
If a single lens is used, then the device size can be reduced, but it is difficult to achieve both convergence and divergence optical characteristics
Solution Approach 1:
The optical system is segmented into two separate lens portions: a first lens portion for achieving convergence and a second lens portion for achieving divergence. Each lens is fixed to a dedicated surface on the housing, allowing independent optimization of their respective functions while maintaining a compact overall device size.
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
A housing (1) provided to a light source device has a sliding surface to which a first lens portion (20) is fixed and an inclined support surface to which a second lens portion (120) is fixed. The sliding surface is vertical to a direction of an optical axis of a semiconductor laser (210,220,230) and wider than a first fixing surface of the first lens portion that is fixed to the sliding surface. The inclined support surface is parallel to the direction of the optical axis and wider than a second fixing surface of the second lens portion that is fixed to the inclined support surface. The housing may contain a RGB laser diode array with a composite prism (4) for combining the individual laser beams into a RGB beam. The two lenses (21,121) may be plane-convex cylindrical lenses for separate collimation along the slow and fast axis of the laser diodes. By providing notches and reference planes for the fixation of the lenses shrinkage of the adhesive used for mounting the lenses has no temperature dependency.