Position Detecting Unit for Absolute Lens Position
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Solution Overview
Problem
Existing position detection methods, such as those using MR sensors, cannot accurately determine the absolute position of an object without moving it to a reference position, leading to prolonged startup times and poor usability in lens units and cameras.
Innovation Solution
A position detection unit comprising a first sensor for monotone signals, a second sensor for sinusoidal signals with offset phases, memory sections for storing signal data, and a position computing section to identify the cycle and calculate the absolute position of the object based on the detected signals, allowing for absolute position detection without moving the object to a reference position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only sinusoidal and cosinusoidal signals from MR sensor are used for position detection, then the detection system is simple, but absolute position cannot be measured
Solution Approach 1:
The patent combines two different detection approaches: a simple monotone signal sensor (first sensor) and a cycle-based sinusoidal signal sensor (second sensor). The monotone signal provides absolute position information, while the sinusoidal signals provide precise relative position data within cycles. By merging these two sensing systems, the patent achieves both absolute position measurement capability and high precision without requiring complex mechanical reference systems.
Solution Approach 2:
The monotone signal acts as an intermediary that bridges the gap between the cyclic sinusoidal signals and the absolute position requirement. The monotone signal monotonically increases or decreases with displacement, providing a reference that allows the system to determine which cycle the sinusoidal signal is in, thereby enabling absolute position measurement while maintaining signal processing simplicity.
2Measurement precision
If the lens is moved to a movable endpoint at startup to detect absolute position, then absolute position can be detected, but startup time is prolonged
Solution Approach 1:
The patent performs preliminary action by pre-storing the relationship between monotone signal values and cycle identifiers in a memory device during manufacturing or initial setup. This allows the system to immediately determine the absolute position cycle without requiring mechanical movement to a reference endpoint at startup, thereby eliminating the time loss while maintaining accurate absolute position detection.
Solution Approach 2:
The patent replaces the mechanical method of determining absolute position (moving the lens to a physical endpoint and counting cycles) with an electronic/signal-based method. The monotone signal, when combined with the stored reference data, electronically identifies the absolute position cycle without requiring mechanical movement, thus substituting a mechanical positioning process with a signal processing approach that is faster and does not cause startup delays.
3Measurement precision
If the lens is moved to a movable endpoint at startup, then absolute position can be detected, but lens position must be reset by user
Solution Approach 1:
The system performs self-service by automatically determining the absolute position cycle through the monotone signal and stored reference data, without requiring user intervention to reset the lens position. The combination of the monotone signal sensor and pre-stored cycle information enables the system to autonomously identify its absolute position state, eliminating the need for manual position resetting and improving ease of operation.
4Loss of time
If monotone signal sensor and sinusoidal signal sensor are combined, then absolute position can be detected without moving to reference position, but device complexity increases
Solution Approach 1:
The patent segments the position detection function into two independent sensor systems: a monotone signal sensor for absolute cycle identification and a sinusoidal signal sensor for precise position measurement within cycles. This segmentation allows each sensor to perform its specialized function with simple hardware, while the complexity is managed through software/signal processing that combines the two signals. The segmentation approach reduces overall system complexity compared to using a single complex sensor system.
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
Enables accurate and efficient detection of absolute positions within the lens unit or camera without the need for initial mechanical movement, reducing startup time and improving usability by directly calculating the object's position using monotone and sinusoidal signals.
Implementation Method 1
an MR sensor (magnetic resistance element) is oriented to oppose an MR sensor magnet
Data Source
AI summary
Position detection unit detecting absolute positions without moving an object to be detected. The detection unit having a first sensor for outputting a monotone signal, that changes in response to displacement of an object to be detected; a second sensor for outputting two sinusoidal signals in response to displacement of the object to be detected; a first memory for storing a monotone signal relative to the position of the object to; a second memory for storing max and min values for each sinusoidal signal; and a position calculator for identifying the cycle of the sinusoidal signal in which the object to be detected is positioned based on the detected monotone signal and stored monotone signal data, and for calculating the position of the object to be detected within the identified cycle and obtaining an absolute position, based on the detected sinusoidal signal and the stored max/min data.