Optical Position Sensor Integration Without Current Sensor Interference
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Solution Overview
Problem
Existing position sensors, particularly those using magnetic field sensing elements, suffer from accuracy degradation when integrated with current sensors due to mutual interference, necessitating a solution that maintains high accuracy and reduces interference.
Innovation Solution
A position sensor system incorporating an optical sensing element and image processor to determine the position of a visual mark on a target, integrated with a current sensor and motor controller within a semiconductor package, allowing for accurate position detection without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If magnetic field sensing elements are integrated with current sensors in the same package, then device integration and compactness are improved, but measurement precision deteriorates due to mutual interference between sensors
Solution Approach 1:
The patent replaces magnetic field sensing elements with an optical sensing element that captures images of a visual mark on the target. This substitution eliminates the harmful magnetic field interactions between position and current sensors, allowing both to coexist in the same semiconductor package without mutual interference, thereby maintaining high measurement precision for both position and current measurements
Solution Approach 2:
The patent introduces an optical intermediary (visual mark and optical sensing element) between the position sensor and target. This intermediary enables position detection through optical imaging rather than magnetic field sensing, effectively decoupling the position sensing mechanism from magnetic field interactions and resolving the interference issue when integrated with current sensors
2Adaptability or versatility
If magnetic field sensing elements are used for position detection, then position sensing capability is achieved, but harmful interference is generated to current sensor measurements
Solution Approach 1:
The patent substitutes magnetic field-based position sensing with optical imaging-based position sensing. The optical sensing element captures images of a visual mark on the target, and image processing determines position. This substitution eliminates the generation of harmful magnetic fields that interfere with current sensor measurements, while maintaining full position sensing capability through optical means
3Measurement precision
If optical sensing element is used instead of magnetic field sensing, then interference with current sensor is eliminated, but device complexity increases due to additional optical components
Solution Approach 1:
The patent merges the position sensor and current sensor into a single semiconductor package, sharing common infrastructure such as the substrate, encapsulation, and light transmissive portions. This integration approach minimizes the actual increase in device complexity despite using optical components, while achieving the benefit of eliminated interference between position and current measurements
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 system ensures high accuracy in position sensing and current measurement by eliminating interference between sensors, suitable for applications requiring precise control and feedback.
Implementation Method 1
an optical sensing element and an image processor, the image processor being configured to use the optical sensing element to take images of a visual mark
Implementation Method 2
a light transmissive portion that is configured to pass through light originating from outside of the package to the optical sensing element
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3~4
AI summary
A device, comprising: a position sensor including an optical sensing element and an image processor, the image processor being configured to use the optical sensing element to take images of a visual mark that is formed on a target, detect a position of the target based on the images, and generate a first signal that is indicative of the position of the target; a current sensor including one or more magnetic field sensing elements, the current sensor being configured to measure a level of electrical current through a conductor, and generate a second signal that is indicative of the level of the electrical current through the conductor; and a motor controller that is configured to receive the first and second signals and generate a third signal for powering an electric motor, the third signal being generated based on the first and second signals; and a semiconductor package.