Optical Encoder Eliminating Mechanical Oscillation via Wavelength Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing scan-type encoders face challenges with increased cost and size due to complex mechanical driving mechanisms for light beam oscillation, and mechanical mounting methods lead to potential position variations and errors in displacement detection due to environmental changes.
Innovation Solution
An encoder design that eliminates physical light modulation by using a light source with periodically changing wavelength, where the optical path lengths of interfering light beams are different, allowing for optical path length differences to create interference fringes without the need for mechanical oscillation mechanisms, reducing errors and device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If mechanical oscillation mechanisms (oscillating mirror or light source) are used to modulate the light beam, then light modulation is achieved, but device complexity and cost increase due to complicated driving mechanisms
Solution Approach 1:
The patent replaces the mechanical oscillation system (oscillating mirror or light source) with an electrical field-based modulation approach. The light beam is modulated by applying an electrical signal to the light source or by using an electro-optic modulator, eliminating the need for mechanical driving mechanisms while achieving the same light modulation effect.
Solution Approach 2:
The patent extracts and removes the mechanical oscillation component from the system. By separating the modulation function from the mechanical oscillation mechanism, the design eliminates the complicated driving mechanism while preserving the essential light modulation capability needed for encoder operation.
2Use of energy by moving object
If mechanical oscillation mechanisms are used, then light beam oscillation is achieved, but device size increases due to required installation space
Solution Approach 1:
The patent substitutes mechanical oscillation with electrical or optical field-based modulation methods. This replacement eliminates the physical space requirements for mechanical components such as oscillating mirrors and their mounting structures, thereby reducing the overall device size while maintaining light beam oscillation functionality.
Solution Approach 2:
The patent transitions from mechanical oscillation in physical space to electrical or optical field modulation in a different dimension (electromagnetic field). This dimensional shift allows the same functional effect to be achieved without occupying physical installation space, thus reducing device size.
3Strength
If mechanical mounting methods (screw fastening, adhesion) are used to support oscillation mechanisms, then structural support is achieved, but position variation occurs due to environmental changes, causing detection errors
Solution Approach 1:
The patent replaces mechanical mounting and support structures for oscillation mechanisms with a solid-integrated design where components are fixed on a single substrate. This eliminates the need for screw fastening or adhesion that cause position variation, thereby improving detection accuracy while maintaining structural support.
Solution Approach 2:
The patent merges multiple components (light source, diffraction gratings, mirrors) onto a single substrate or integrated structure. This consolidation eliminates the need for separate mechanical mounting of oscillation mechanisms, reducing position variation due to environmental changes and improving measurement precision.
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 solution reduces the complexity and cost of the device, minimizes errors in displacement detection, and stabilizes the measurement by avoiding mechanical mounting-related issues such as drifting caused by temperature or humidity changes.
Implementation Method 1
a light source section which emits light, a wavelength of which periodically changes
Implementation Method 2
a first optical member which receives the light emitted from the light source section and then emits a first light and a second light
Implementation Method 3
a second optical member which changes a travelling direction of the first light or the second light such that the first and second light emitted from the first optical member overlap each other
Implementation Method 4
a diffraction grating member which is disposed at a position where the first light and the second light overlap each other, is displaced relatively with respect to the light source section, the first optical member, and the second optical member, and has a diffraction grating periodically formed along a movement direction
Implementation Method 5
a first light receiving section which receives an interfering light of the first and second light, which is emitted from the diffraction grating member, and detects an interference intensity of the interfering light
Data Source
AI summary
An encoder emits modulated light from a light source section and lets a first light and a second light separated from the modulated light interfere with each other in a moving grating. In the encoder, the light emitted from the light source section is electrically modulated, and the first light and the second light have different light path lengths.