Rectangular Optical Filter Vibration for Dust Removal
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Solution Overview
Problem
Existing optical apparatuses face challenges in efficiently removing foreign substances like dust from optical members without increasing cost, complexity, or reducing optical performance, as previous solutions require dedicated dust-proof screens or multiple piezoelectric elements, leading to space inefficiencies and noise generation.
Innovation Solution
A digital single-lens reflex camera design featuring a rectangular optical member with a rectangular piezoelectric vibrating device that operates in multiple vibration modes, including even and odd node configurations, to effectively remove dust from optical low-pass filters using a single piezoelectric element, minimizing cost and size while preventing noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated circular dust-proof screen is disposed between the image sensor and mechanical shutter, then dust removal capability is improved, but the optical member size increases and optical performance deteriorates
Solution Approach 1:
The patent applies the universality principle by making the optical low-pass filter serve dual functions: it acts as both the optical filter required for imaging and as the dust-proof screen for removing foreign substances. This eliminates the need for a separate dedicated dust-proof screen, thereby reducing the overall optical member size while maintaining effective dust removal capability through the vibrating member that induces resonant vibrations in the filter.
2Reliability
If multiple piezoelectric elements are used to vibrate the optical member, then dust removal effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies the merging principle by combining the functions of multiple piezoelectric elements into a single piezoelectric element. The single element is strategically positioned to induce resonant vibrations in the optical low-pass filter, achieving effective dust removal across the entire filter surface through resonant modes, thereby reducing device complexity and cost while maintaining dust removal effectiveness.
3Reliability
If the optical member is vibrated in first-order bending vibration mode, then dust removal is achieved, but low operation sound noise is generated
Solution Approach 1:
The patent applies the parameter changes principle by changing the vibration mode parameters from first-order bending vibration to higher-order resonant vibrations. By operating at higher vibration modes, the system achieves effective dust removal while avoiding the low-frequency resonant frequencies that generate audible noise, thus eliminating the harmful sound noise while maintaining dust removal reliability.
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 solution enables efficient dust removal from optical members without compromising optical performance, reduces the number of piezoelectric elements, and simplifies control processes, achieving miniaturization and cost-effectiveness while maintaining high image quality.
Implementation Method 1
a vibrating member for vibrating a peripheral edge portion of the optical member is provided in the camera and causes the optical member to perform resonant vibrations
Implementation Method 2
causes the optical member to perform resonant vibrations while switching between first-order and second-order vibration modes
Data Source
AI summary
An optical apparatus includes a rectangular optical member provided on an optical axis, and a rectangular vibrating device stuck to the optical member close to and in parallel with one of four sides of the optical member and configured to vibrate the optical member in a wave fashion to have a plurality of nodes parallel with the one side. The vibrating device is configured to operate in two or more vibration modes differing from one another at least in number or positions of the plurality of nodes.