Spatial Light Modulator Phase Control for Optical Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In mobile light communication, achieving high directivity while avoiding interference requires precise optical axis alignment, often necessitating mechanical gimbals, increasing device size and cost. Phase-modulation spatial light modulating elements face challenges with infinite focal distance and polarization mismatches, leading to communication failures with position or posture changes.
Innovation Solution
A receiving device that generates a phase image based on transmitter position, combines it with a virtual lens image to create a composite image, and uses a phase-modulation spatial light modulating element to diffract and collect signal light, allowing for directional control and shortening the focal distance without the need for mechanical gimbals or Fourier transform lenses, and includes a polarizing element to ensure proper polarization alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical gimbal is used to match optical axis alignment between transmission/reception units, then alignment precision is improved, but device size and cost increase
Solution Approach 1:
The patent replaces mechanical gimbals with a phase-modulation spatial light modulating element that uses optical phase modulation to achieve directional control of light. This substitution eliminates mechanical moving parts while maintaining alignment precision through electrical control of the spatial light modulator's phase patterns.
Solution Approach 2:
The patent changes the control parameter from mechanical angle adjustment to optical phase modulation. By controlling the phase distribution across the spatial light modulator, the system achieves directional beam control without mechanical movement, thereby reducing device complexity while maintaining alignment precision.
2Length of moving object
If a Fourier transform lens is provided at a latter part of the phase-modulation spatial light modulating element to shorten focal distance, then focal distance is shortened, but device size and cost increase
Solution Approach 1:
The patent makes the phase-modulation spatial light modulating element perform multiple functions: it both modulates the phase of incident light and acts as a focusing element to shorten the focal distance. By programming appropriate phase patterns, the spatial light modulator replaces the need for additional Fourier transform lenses, reducing device size and cost.
Solution Approach 2:
The patent creates a virtual Fourier transform lens effect through phase modulation patterns on the spatial light modulator. Instead of using a physical lens, the system uses computationally generated phase patterns to achieve the same optical focusing effect, thereby eliminating the need for additional optical components.
3Reliability
If polarization of the phase-modulation spatial light modulating element and polarization of the light do not match, then communication reliability deteriorates, but in mobile communication position and posture changes cause polarization mismatch
Solution Approach 1:
The patent changes the polarization state parameter by introducing a polarizing element that converts incident light into a standardized polarization state before it reaches the spatial light modulator. This ensures consistent polarization matching regardless of the transmitter's position or posture, maintaining communication reliability in mobile scenarios.
Solution Approach 2:
The patent introduces a polarizing element as an intermediary component between the incident light and the spatial light modulator. This intermediary ensures that the polarization state is standardized and matched to the modulator's requirements, acting as a buffer that decouples the system from polarization variations caused by mobile position and posture changes.
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 enables compact, cost-effective, and position-independent light communication by reducing the distance between the phase-modulation spatial light modulating element and detector, ensuring continuous communication regardless of transmitter-receiver position or posture changes.
Implementation Method 1
a phase-modulation spatial light modulating element configured to diffract and collect the signal light in response to the composite image supplied thereto
Implementation Method 2
a polarizing element configured to convert the circularly polarized signal light into linearly polarized signal light
Data Source
AI summary
This communication system includes: at least one transmitter which emits signal light; and a receiving device which receives the signal light. The receiving device is provided with: a control unit which generates a phase image on the basis of position information indicating a position of the transmitter, and combines a virtual lens image with the phase image to generate a composite image; a phase-modulation spatial light modulating element which receives the composite image and diffracts and collects signal light; and a detector which receives the diffracted and collected signal light.