Print Head Lens Bonding Layout to Prevent Array Warping
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Solution Overview
Problem
Warping of the lens array due to adhesive shrinkage occurs in print heads, leading to inconsistent focus and misalignment of light-emitting elements, as the adhesive cures and causes the lens array to bow, particularly when bonding regions are concentrated on one side of the optical axis.
Innovation Solution
The lens array and lens holder are bonded in alternating first and second bonding regions on opposite sides of the optical axis, with adhesive applied in specific patterns to counteract shrinkage forces, preventing warping by balancing the forces exerted on the lens holder and array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bonding regions are concentrated on one side of the optical axis, then the adhesive application process is simplified, but the lens array warps due to unbalanced adhesive shrinkage forces
Solution Approach 1:
The patent applies asymmetry in reverse (symmetry) by arranging bonding regions symmetrically on both sides of the optical axis. This symmetric distribution balances the shrinkage forces from the adhesive, preventing warping of the lens array while maintaining ease of manufacture through a systematic bonding pattern.
Solution Approach 2:
The patent uses counterweight by placing bonding regions on opposite sides of the optical axis to counterbalance the shrinkage forces. The adhesive shrinkage on one side is compensated by the opposing shrinkage force from the other side, preventing net warping of the lens array.
2Stability of the object's composition
If multiple bonding regions are used to prevent warping, then lens array stability is improved, but the complexity of the bonding structure increases
Solution Approach 1:
The patent applies segmentation by dividing the bonding interface into multiple discrete bonding regions rather than a continuous bond. This segmented approach provides sufficient stability to prevent warping while keeping the bonding structure relatively simple and manageable.
Solution Approach 2:
The patent applies local quality by concentrating adhesive bonding at specific strategic locations (bonding regions) rather than uniformly across the entire interface. This localized bonding provides sufficient stability to prevent warping while minimizing the overall complexity and adhesive material required.
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 effectively reduces warping of the lens array, maintaining consistent focus and alignment of light-emitting elements, thereby improving image quality in print heads.
Implementation Method 1
the adhesive may shrink as the adhesive cures, causing the lens array to warp (curve) into a bow shape
Data Source
AI summary
A print head 3 includes: a substrate (311) having a plurality of light-emitting elements 31; an elongated lens array 32, and an elongated lens holder 313. The lens array 32 and the lens holder 313 are bonded to each other in a plurality of bonding regions H(1) to H(n) arranged in a longitudinal direction L within a facing area α where the lens array 32 and the lens holder 313 face each other. The plurality of bonding regions H(1) to H(n) include first bonding regions H(2), . . . , and H(n-1) located on one side in an optical axis direction N of the plurality of light-emitting elements 31 and second bonding regions H(1), H(3), . . . , and H(n) located on an opposite side in the optical axis direction N.