Optical Writer Rod Lens Array Thermal Expansion Compensation
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Solution Overview
Problem
Traditional optical writers with gradient-index rod lens arrays suffer from image quality issues due to fabrication errors, thermal expansion differences between the light source substrate and the rod lens array, and uneven adhesive application, leading to displacement and distortion of rod lenses.
Innovation Solution
An optical writer design featuring a rod lens array with restraining plates bonded using thin adhesive layers, where the plates have a lower linear expansion coefficient than the rod lens array, and are configured to condense light onto an image retainer, with the light source substrate bonded directly or via an intermediate member to the holder using thin adhesive layers, and the rod lens array bonded to the holder with thicker adhesive layers, ensuring stability and preventing warp and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the rod lens array is bonded to the holder with thin adhesive layers to achieve high bearing surface accuracy, then the bonding precision is improved, but the rod lenses become susceptible to displacement due to thermal expansion differences
Solution Approach 1:
The patent changes the adhesive layer thickness parameter from thin to thick specifically for bonding the rod lens array to the holder. This thick adhesive layer acts as a buffer that absorbs thermal expansion differences between the rod lens array and holder, preventing rod lens displacement while maintaining bonding reliability under temperature variations
Solution Approach 2:
The patent introduces a restraining plate as an intermediary component between the rod lens array and holder. This restraining plate with matching thermal expansion coefficient serves as a mediator that compensates for thermal expansion differences, allowing the use of thin adhesive layers for precise bonding while maintaining thermal stability
2Manufacturing precision
If the restraining plate is bonded to the rod lens array with thin adhesive layers to achieve uniform bonding, then the bonding precision is improved, but the adhesive layers become uneven causing peeling and distortion
Solution Approach 1:
The patent changes the adhesive layer thickness parameter for bonding the restraining plate to the rod lens array, using thin adhesive layers that are uniform in thickness. This uniform thin bonding achieves both precision and reliability by preventing the peeling issues that occur with uneven thick adhesive layers
3Reliability
If the rod lens array is bonded to the holder with thick adhesive layers to compensate for thermal expansion, then the thermal stability is improved, but the bonding precision and alignment accuracy deteriorate
Solution Approach 1:
The patent segments the bonding structure into two distinct parts: (1) thin adhesive layers for bonding the restraining plate to the rod lens array to ensure precision and alignment accuracy, and (2) thick adhesive layers for bonding the rod lens array to the holder to provide thermal expansion compensation. This segmentation allows each bonding interface to be optimized for its specific function
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 prevents displacement of rod lenses relative to luminous points due to environmental temperature variations, maintains image quality by preventing warp and distortion of the rod lens array, and ensures precise bonding through equalized adhesive layers, reducing thermal expansion differences and peeling issues.
Implementation Method 1
a rod lens array including a plurality of rod lenses having an optical axis, the rod lens array having a higher linear expansion coefficient than a linear expansion coefficient of the base of the light source substrate and the rod lens array being configured to condense light from the light sources onto an image retainer
Implementation Method 2
the restraining plates and the holder each have a lower linear expansion coefficient than the linear expansion coefficient of the rod lens array
Data Source
AI summary
Disclosed is an optical writer including a light source substrate including a base and a plurality of light sources disposed on the base, a rod lens array comprising a plurality of rod lenses having an optical axis, the rod lens array having a higher linear expansion coefficient than a linear expansion coefficient of the base of the light source substrate and the rod lens array being configured to condense light from the light sources onto an image retainer, a holder supporting the light source substrate and the rod lens array and restraining plates bonded to respective elongated faces of the rod lens array with thin adhesive layers, the elongated faces being parallel to the optical axis of the rod lenses, wherein the restraining plates and the holder each have a lower linear expansion coefficient than the linear expansion coefficient of the rod lens array.