Laser Beat Signal Probe Contact Detection
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Solution Overview
Problem
Existing optical measurement apparatuses face challenges in reliably detecting contact between a measurement probe and body tissue, which affects the accuracy of characteristic value calculations for body tissues, especially when the probe and tissue surfaces move relative to each other.
Innovation Solution
A contact detecting apparatus using a laser light source and a signal processing unit to determine contact by analyzing the presence of a beat signal caused by interference between the return light scattered from the body tissue and the probe's surface, allowing for accurate detection of contact and improved measurement reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a measurement probe is used to emit illumination light onto body tissue and receive scattered return light, then optical measurement of body tissue characteristics can be performed, but reliable detection of contact between the probe and body tissue becomes difficult when the probe and tissue surfaces move relative to each other
Solution Approach 1:
The patent introduces laser light as an intermediary to detect contact between the measurement probe and body tissue. The laser light source emits laser light that reflects off the distal end surface of the measurement probe, and this reflected light serves as a mediator to indicate contact status. When the probe contacts the tissue, the relative motion stops and the laser light reflection pattern changes, providing a reliable contact detection mechanism that works even during probe movement.
Solution Approach 2:
The patent utilizes changes in laser light reflection parameters (intensity, pattern, or frequency) to detect contact between the measurement probe and body tissue. By monitoring how the reflected laser light parameters change when the probe transitions from non-contact to contact state, the system can reliably determine contact status independent of overall probe movement, thus improving measurement reliability under relative motion conditions.
2Ease of operation
If the measurement probe moves relative to the body tissue during measurement, then flexibility and ease of operation are improved, but contact detection accuracy deteriorates
Solution Approach 1:
The patent replaces mechanical contact detection methods with an optical detection system using laser light. Instead of relying on mechanical sensors or physical contact indicators that would restrict probe movement, the system uses laser light reflection to detect contact status. This substitution allows the measurement probe to move freely for ease of operation while the optical laser detection system accurately determines when contact with the tissue occurs.
3Device complexity
If traditional optical measurement methods are used without contact detection, then device complexity is reduced, but measurement reliability deteriorates due to inability to distinguish contact from non-contact scenarios
Solution Approach 1:
The patent makes the laser light serve multiple functions: it acts as both the measurement illumination source and the contact detection mechanism. The same laser light that illuminates the tissue for optical measurement also reflects off the probe distal end surface to indicate contact status. This multi-functionality adds minimal complexity to the system while significantly improving measurement reliability by enabling contact detection alongside the primary measurement function.
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 reliable detection of contact between the measurement probe and body tissue, ensuring accurate measurement results by distinguishing between contact and non-contact scenarios based on the presence of a beat signal, thereby enhancing the reliability of the optical measurement process.
Implementation Method 1
return light of the illumination light scattered from the body tissue
Implementation Method 2
interference of the return light of the laser light scattered from each of a surface of the body tissue and a surface of the distal end of the measurement probe
Implementation Method 3
a photoelectric conversion unit configured to convert light received via the measurement probe into an electric signal
Implementation Method 4
a component of a beat signal caused by interference of the return light of the laser light scattered from each of a surface of the body tissue and a surface of the distal end of the measurement probe
Data Source
AI summary
A contact detecting apparatus detects contact between a body tissue and a probe for emitting illumination light onto the body tissue and receiving return light of the illumination light scattered from the body tissue. The contact detecting apparatus includes: a laser light source that emits laser light to irradiate a specified region of the body tissue via the probe; a photoelectric conversion unit that converts light received via the probe into an electric signal; and a signal processing unit that determines whether or not there is contact between a distal end of the probe and the body tissue based on whether the electric signal includes a component of a beat signal caused by interference of the return light of the laser light scattered from each of a surface of the body tissue and a surface of the distal end of the probe.