Lens Unit Thermal Expansion Alignment via Extraction
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Solution Overview
Problem
Conventional lens units for small electronic devices face challenges in maintaining optical performance after reflow soldering due to thermal expansion, as screw-based focus adjustment mechanisms are prone to misalignment and limited in precision, especially when the lens unit is miniaturized.
Innovation Solution
A lens unit design featuring a curable resin lens, an elastic aperture member, and a hollow holder with specific geometric features such as flat surfaces, inclined surfaces, and gaps to maintain precise alignment and optical performance, eliminating the need for focus adjustment mechanisms and minimizing distortion from thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a screw-based focus adjustment mechanism is used, then focus adjustment is achieved, but the mechanism is prone to misalignment due to thermal expansion and cannot be miniaturized
Solution Approach 1:
The patent removes the screw-based focus adjustment mechanism entirely from the lens unit. Instead, focus adjustment is performed externally on the circuit board mounting position, extracting the problematic mechanical screw mechanism from the thermal environment and replacing it with a simpler, more reliable structure that does not require internal focus adjustment components.
Solution Approach 2:
The patent replaces the mechanical screw-based focus adjustment system with an alternative approach where focus is controlled by the mounting position of the entire lens unit on the circuit board. This substitution eliminates the need for internal mechanical adjustment mechanisms that are susceptible to thermal expansion and misalignment.
2Volume of moving object
If the lens unit is miniaturized, then device size is reduced, but optical performance deteriorates due to thermal expansion effects
Solution Approach 1:
The patent extracts the focus adjustment function from the lens unit itself and relocates it to the circuit board mounting level. This allows the lens unit to be miniaturized without including bulky adjustment mechanisms, while focus precision is maintained through external positioning control that is not affected by thermal expansion of small components.
3Ease of operation
If screws are used for focus adjustment, then adjustment mechanism is provided, but the screws tilt relative to optical axis under high temperature causing position change
Solution Approach 1:
The patent removes the screw-based adjustment mechanism from the lens unit structure entirely. Focus adjustment is achieved by positioning the entire lens unit at the appropriate location on the circuit board, eliminating the source of thermal expansion-induced tilting and misalignment problems.
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 design allows for a compact, high-performance lens unit that maintains optical alignment and performance before and after thermal expansion, preventing deterioration in optical performance and enabling further miniaturization of the device.
Implementation Method 1
a lens (4) formed of curable resin
Implementation Method 2
an aperture member (3) formed of an elastic body
Implementation Method 3
changes in optical performance be as small as possible due to thermal expansion of each part of the lens unit in the reflow soldering process
Data Source
AI summary
It is provided a lens unit to be small-sized, while reducing deterioration in optical performance after experiencing thermal expansion. The lens unit includes an aperture member, a lens, an image sensor, and a holder. A range where the aperture member abuts on a flange part of the lens overlaps with a range where the holder abuts on the flange part of the lens. A first gap is provided between a holder inclined surface of the holder and a lens inclined surface of the lens over the entire circumference. A second gap is provided between an outer circumferential surface of the lens and an inner surface of the holder over the entire circumference.