Truncated Cone Prism Optical Displacement Measurement
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Solution Overview
Problem
Conventional optical displacement measuring techniques face challenges in achieving high-precision measurements on uneven surfaces, particularly in confined spaces, due to oblique light incidence which can result in measurement errors and limited range.
Innovation Solution
The use of a truncated cone shaped prism with a broad-area and narrow-area flat portion, where light is introduced through the narrow-area side to the object, allowing vertically incident light to prevent position variation with displacement, combined with a pinhole optical device to extract parallel light for precise detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If oblique light incidence is used in conventional optical measurement, then the light can be directed to the object, but measurement precision deteriorates on uneven surfaces due to position variation
Solution Approach 1:
Instead of directing light obliquely as in conventional methods, the invention inverts the approach by using a truncated cone shaped prism to convert oblique incident light into vertically incident light on the object surface. This inversion of light direction ensures consistent illumination regardless of surface unevenness, thereby maintaining measurement precision while still enabling light to reach the object effectively.
Solution Approach 2:
The truncated cone shaped prism acts as an intermediary optical element between the light source and the object. It receives oblique incident light and transforms it into vertically incident light through its specific geometric structure, thereby mediating the light path to achieve both effective light delivery and precise measurement on uneven surfaces.
2Measurement precision
If triangulation system is used with light source at sufficient distance, then high-precision measurement is achieved, but device size increases and confined spaces cannot be accessed
Solution Approach 1:
The invention nests multiple optical functions within a compact truncated cone shaped prism structure. The prism integrates light reception, light transformation, and measurement capabilities in a single compact component, eliminating the need for a large-distance light source configuration while maintaining measurement precision and enabling access to confined spaces.
Solution Approach 2:
The invention changes the geometric parameters of the optical system by using a truncated cone shaped prism with specific apex angles. This parameter change allows the system to achieve high-precision measurement in a compact form factor, transforming the traditional requirement of large light source distance into a compact integrated structure that can access confined spaces.
3Measurement precision
If optical probe method is used for highly sensitive detection, then detection sensitivity is improved, but measurement range is limited to area close to focused position
Solution Approach 1:
The invention introduces dynamic adaptability by using a truncated cone shaped prism that can effectively measure displacement across a broader range of distances. The prism's geometric structure allows it to maintain detection sensitivity while adapting to objects at various distances, transforming the static, narrow measurement range of conventional optical probes into a dynamic, versatile measurement system.
4Adaptability or versatility
If automatic focusing technique is used for broader measurement range, then measurement range is improved, but measurement speed decreases due to lens tracking issues
Solution Approach 1:
The invention extracts the focusing mechanism from the measurement system by using a truncated cone shaped prism that inherently provides consistent light incidence across different object distances. This eliminates the need for dynamic lens focusing operations, thereby maintaining a broad measurement range while significantly improving measurement speed by removing the bottleneck of lens tracking.
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 enables high-precision displacement measurement on uneven surfaces by stabilizing light incidence and enhancing displacement resolution, while preventing internal reflections and light loss, thus allowing for compact and efficient measurement systems.
Implementation Method 1
Light emitted from behind the objective lens is introduced into the objective lens and refracted on a cone-shaped interface of the objective lens to irradiate the object, and light reflected from the object is returned to the objective lens, refracted again by the cone-shaped interface, and delivered in parallel to the light which is initially emitted.
Implementation Method 2
the inbound light is focused by a condenser lens at a focus point, to thereby suppress effects of scattered light by means of a pinhole optical device disposed at the focus point.
Data Source
AI summary
An optical displacement measuring apparatus includes a light source, a collimate lens, a mirror, and a truncated cone shaped prism, and includes an imaging lens and a pinhole optical device for extracting light parallel to an optical axis of incident light from light returned from an object through the truncated cone shaped prism, and an optical position detector. The truncated cone shaped prism has optical properties of converting only light returned to a truncated conical circumference surface at a fixed angle corresponding to an apex angle into light parallel to an optical axis of incident light. The parallel light is offset from an optical axis of incident light in accordance with a displacement of the object relative to the truncated cone shaped prism. The optical position detector detects an offset amount to measure the displacement of the object.