Rolling Electrostatic Filter for Dust Capture in Projectors
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Solution Overview
Problem
Projection type image display apparatuses face challenges in maintaining dust capture efficiency over long periods due to the need for frequent filter renewal, especially in dusty environments, which increases maintenance efforts and device size.
Innovation Solution
A dust capture device with first and second winding shafts, a rolled electrostatic filter, and a brush mechanism that automatically renews and cleans the filter by taking up and rewinding it, ensuring the filter remains effective for extended periods without increasing the filter size or maintenance efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrostatic filter is used to capture small dust particles, then dust capture capability is improved, but the filter cannot be cleaned and must be replaced frequently
Solution Approach 1:
The patent implements an automatic filter renewal mechanism where a used filter is discarded and a new filter is automatically deployed from a rolled state. The feeding mechanism advances the filter in the direction of air flow when dust accumulation reduces capture capability, eliminating manual intervention for filter replacement while maintaining continuous dust capture functionality.
2Duration of action of stationary object
If the filter size is increased to extend the renewal interval, then dust capture duration is improved, but the device size increases
Solution Approach 1:
The patent employs a rolled filter configuration that can dynamically extend the filter surface area as needed. Instead of using a large static filter, the system stores the filter in a compact rolled state and automatically unrolls it in the direction of air flow when renewal is required, enabling extended filter service life without increasing the overall device volume.
3Reliability
If filters are renewed manually in ceiling-mounted projectors, then filter condition can be maintained, but maintenance complexity increases
Solution Approach 1:
The patent implements a self-service automatic filter renewal system where the projector autonomously monitors filter status and executes renewal operations without manual intervention. The feeding mechanism automatically advances the filter in the air flow direction when dust accumulation is detected, and the system can be ceiling-mounted without requiring users to access difficult-to-reach filter compartments for manual maintenance.
4Reliability
If a urethane filter with small openings is used, then dust capture is improved, but pressure loss increases
Solution Approach 1:
The patent utilizes an electrostatic filter that changes the dust capture mechanism from physical blocking to electrostatic attraction. This parameter change allows the filter to capture small dust particles including yellow sand and cigarette smoke without requiring small physical openings, thereby maintaining low pressure loss while achieving high dust capture efficiency.
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 maintains high dust removal capability over long hours with reduced maintenance, allowing for downsizing and various model development while preventing dust entry into the device, thus enhancing performance and usability in dusty environments.
Implementation Method 1
the electrostatic filter can capture small dust because the dust is captured using static electricity
Data Source
AI summary
The present invention includes: a rolled filter stretched between first and second winding shafts and, unused part of the filter being wound around the second winding shaft; a brush provided between the first and the second winding shafts so as to come into contact with a surface of the filter; a feeding mechanism for driving the first and the second winding shafts to take up or rewind the filter; and a feeding control unit for controlling the feeding mechanism. When activating a renewing operation for feeding unused part of the filter from the second winding shaft, the feeding control unit controls the feeding mechanism such that once the filter is taken up by the first winding shaft by an take-up amount La, the filter is rewound by the second winding shaft by a rewind amount Lb, and La and Lb satisfy a relationship La≧Lb. Without increasing the amount of the filter or the size of the device itself, the present invention can deliver adequate performance even in a dusty environment by a small number of filter renewing operations.