Laser Rangefinder Compact Design via Oscillating Mirror and Extraction
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Solution Overview
Problem
Existing laser rangefinders face challenges in achieving compactness and wide-angle distance measurement due to motor size dependencies and limited light projection areas when using motors or small scanning mirrors, which hinder effective detection of distant targets.
Innovation Solution
The implementation of an optical configuration using an oscillating mirror, first and second optical components disposed outside the laser light path, and a photodetector to condense reflected light, reducing optical feedback and increasing the light detection area, allowing for compact and wide-angle distance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a motor is used to rotate the optical systems, then the laser rangefinder can measure distance across a wide area, but the device size increases due to motor weight
Solution Approach 1:
The patent replaces the motor-driven rotation system with a scanning mirror system. Instead of using a motor to physically rotate the entire optical system, a scanning mirror is used to deflect the laser beam across the scanning area. This substitution eliminates the need for a heavy motor while maintaining the wide-area scanning capability, thus resolving the contradiction between scanning area and device size.
2Weight of stationary object
If a small scanning mirror is used, then the device can be made compact, but the light detection area is limited reducing distant target detection capability
Solution Approach 1:
The patent introduces additional optical components (condensing lenses) that manipulate the optical paths in three-dimensional space. By using multiple condensing lenses positioned at different locations, the system collects reflected light from a wider area and focuses it onto the photodetector. This dimensional approach allows a small scanning mirror to effectively detect light from a larger area, resolving the contradiction between device compactness and light detection area.
3Use of energy by moving object
If optical components are placed on the laser light path, then light collection is improved, but optical feedback increases causing measurement errors
Solution Approach 1:
The patent extracts the optical feedback problem by positioning the condensing lenses specifically on the reflected light path rather than the emitted laser light path. The first condensing lens collects reflected light from the target, and the second condensing lens focuses this collected light onto the photodetector. By separating the optical paths and strategically placing components only where needed for reflected light collection, the system improves light collection efficiency while minimizing optical feedback interference.
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 a compact laser rangefinder capable of measuring distances to distant targets with increased light detection, effectively addressing the limitations of previous technologies by minimizing optical feedback and enhancing light collection across a wider angle.
Implementation Method 1
an oscillating mirror that scans the laser light emitted from the light source by oscillating about an axis of oscillation
Implementation Method 2
a first optical component that is disposed on an optical path of first reflected light and condenses the first reflected light onto the oscillating mirror
Implementation Method 3
a second optical component that is disposed on an optical path of second reflected light and condenses the second reflected light, the second reflected light being the condensed first reflected light reflected from the oscillating mirror
Implementation Method 4
a photodetector that receives the second reflected light condensed by the second optical component
Data Source
AI summary
A laser rangefinder includes a light source, a scanning mirror that scans laser light emitted from the light source by oscillating about an axis of oscillation J extending in a predetermined direction, a first lens that is disposed on an optical path of reflected light from a target object and condenses the reflected light onto the scanning mirror, a second lens that is disposed on an optical path of and condenses reflected light from the scanning mirror, and a photodetector that receives the reflected light condensed by the second lens. The first lens and the second lens are disposed in positions other than positions on an optical path of the laser light between a point of emission from the light source and a point of exit from the laser rangefinder.