Small-Height Scan Engine Lens Holder Alignment for Dimensional Fit
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Solution Overview
Problem
In small-height scan engines, dimensional tolerances and optical alignment issues result in overall dimensions exceeding maximum allowed sizes, leading to mounting challenges and potential disengagement of the lens holder from the circuit board.
Innovation Solution
A method involving optical alignment of a lens holder with an image sensor followed by physical alignment with the circuit board, using alignment fixtures and machine vision, ensures coplanarity of the lens holder surface with the circuit board edge, thereby controlling overall dimensions within allowable limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mounting methods are used with nominal dimensions and tolerances, then optical alignment can be achieved, but the overall dimension exceeds the maximum allowed size
Solution Approach 1:
The patent applies preliminary action by performing optical alignment first to establish the precise positional relationship between the lens holder and image sensor, then using this established relationship as a basis for subsequent physical alignment. The alignment fixtures are prepared in advance with reference surfaces that facilitate this two-stage alignment process, ensuring that optical precision is achieved before dimensional constraints are addressed.
Solution Approach 2:
The patent introduces alignment fixtures as intermediary tools that mediate between the lens holder and circuit board. These fixtures provide reference surfaces and mechanical constraints that enable both optical alignment and physical alignment to occur within the same coordinate system, bridging the gap between optical precision requirements and dimensional constraints.
2Length of stationary object
If the lens holder is physically aligned with the circuit board edge, then dimensional requirements are met, but optical alignment may be compromised
Solution Approach 1:
The patent performs optical alignment as a preliminary action before physical alignment with the circuit board edge. By establishing the optical axis and positional relationship between the lens holder and image sensor first, the system creates a reference framework that guides the subsequent physical alignment process, ensuring that dimensional constraints are applied without compromising optical precision.
Solution Approach 2:
The alignment fixtures serve as intermediaries that maintain the optical alignment relationship during physical alignment. The fixtures' reference surfaces are designed to preserve the positional relationship established during optical alignment, allowing the lens holder to be physically aligned with the circuit board edge while maintaining optical precision through the mediating constraint of the fixture geometry.
3Ease of manufacture
If tolerances in circuit board and lens holder dimensions are present, then manufacturing is feasible, but mounting forces increase causing potential disengagement
Solution Approach 1:
The alignment fixtures act as intermediaries that absorb and compensate for dimensional tolerances in the circuit board and lens holder. By providing precise reference surfaces and mechanical constraints, the fixtures ensure that components with varying dimensions within tolerance ranges can still be aligned and mounted reliably, reducing the forces that would otherwise cause misalignment or disengagement.
Solution Approach 2:
The patent changes the alignment parameters from direct component-to-component contact to fixture-mediated alignment. By introducing the fixtures as an additional degree of freedom in the alignment process, the system can accommodate dimensional variations in the circuit board and lens holder while maintaining consistent mounting forces and alignment precision, thereby improving reliability despite manufacturing tolerances.
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 method effectively aligns the lens holder with the circuit board, ensuring the scan engine meets dimensional requirements and reduces mounting forces, preventing disengagement, and potentially improving optical alignment accuracy.
Implementation Method 1
optically aligning, using one or more alignment fixtures, a lens holder holding one or more lenses or optical elements with the image sensor based upon one or more images captured by the image sensor through the lens holder
Implementation Method 2
capturing, with a machine vision camera, one or more first images of the edge of the circuit board together with the surface of the lens holder
Data Source
AI summary
Methods and apparatus for aligning a lens holder in a small-height scan engine are disclosed herein. An example method for aligning a lens holder in a small-height scan engine includes: mounting an image sensor to a circuit board; optically aligning, using one or more alignment fixtures, a lens holder holding one or more lenses or optical elements with the image sensor based upon one or more images captured by the image sensor through the lens holder; and after the lens holder and image sensor are optically aligned, physically aligning, using the one or more alignment fixtures, the lens holder with the circuit board based upon a misalignment between a surface of the lens holder and an edge of the circuit board.