Hall Sensor Stress Reduction in Optical Scanning Apparatus
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Solution Overview
Problem
The existing scanning optical apparatuses face issues where the circuit board, fixed to the optical box with small screws, experiences deformation due to pressure, leading to stress on electrical components, which can cause the Hall element to fail in outputting a preset voltage, resulting in erratic behavior of the rotational polygonal mirror.
Innovation Solution
The circuit board is designed with Hall elements positioned on areas of minimal deformation, minimizing stress, and the optical box is modified with additional contacting portions to distribute pressure evenly, reducing the stress on the Hall elements and ensuring accurate output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the circuit board is fixed to the optical box with small screws, then the circuit board can be securely mounted, but the circuit board deforms due to pressure from the supporting portions
Solution Approach 1:
The circuit board is designed with locally differentiated properties: the Hall element is positioned in a specific region (first region) that has different mechanical characteristics compared to other areas. This local quality difference ensures that the sensitive Hall element area experiences minimal deformation while the board as a whole remains securely mounted through the screw holes and supporting portions.
2Reliability
If the circuit board deforms, then the electrical components are subjected to stress, but this causes the Hall element to fail in outputting preset voltage
Solution Approach 1:
The circuit board structure is designed with local quality differentiation where the first region containing the Hall element has optimized mechanical properties to minimize stress concentration. This localized design ensures that the Hall element maintains its electrical characteristics and output accuracy while other parts of the board can accommodate mounting stresses.
3Measurement precision
If the Hall element is subjected to stress, then it may fail to output preset voltage, but this causes the deflecting device to deviate in rectification timing
Solution Approach 1:
The circuit board is designed with a specific regional differentiation where the first region housing the Hall element possesses optimized mechanical characteristics that minimize deformation under mounting stress. This local quality enhancement ensures that the Hall element maintains precise voltage output proportional to magnetic flux density, thereby ensuring accurate rectification timing for the rotational polygonal mirror.
4Stress or pressure
If additional contacting portions are added to the optical box, then pressure is distributed evenly, but the device complexity increases
Solution Approach 1:
The optical box is designed with segmented structural features including multiple contacting portions that distribute pressure across different locations. This segmentation approach divides the pressure distribution function into discrete contact points, achieving even pressure distribution while maintaining a relatively simple overall structure that integrates well with the existing optical box design.
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 allows the Hall elements to maintain a preset voltage output proportional to magnetic flux density, preventing the deflecting device from deviating in rectification timing and ensuring stable operation of the rotational polygonal mirror.
Implementation Method 1
If a Hall element is subjected to stress, it is possible that it will fail to output a preset amount of voltage which is proportional to a preset level of magnetic flux density
Data Source
AI summary
An optical scanning apparatus includes a deflector for deflecting a beam emitted from a light source, the deflector including a rotatable polygonal mirror for reflecting the beam, a motor for rotating the rotatable polygonal mirror, a substrate carrying the motor and provided with a circuit for driving the motor, and a magnetometric sensor carried on the substrate; an optical box accommodating the deflector. The substrate is provided with two holes for fastening the substrate to the optical box. The optical box is provided with two contact portion contacting the substrate in a state that the substrate is fastened to the optical box through the two holes. The magnetometric sensor is disposed at a position closer to a line m connecting the two holes than to a line n connecting two positions on the substrate where the two contact portions contact.