Optical Scanning Apparatus Using Galvanometer Mirror for Compact Imaging
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Solution Overview
Problem
Existing image pickup apparatuses with distal end scanners face challenges in reducing size while achieving high-definition imaging, as they require a scanning mechanism for point scanning, which limits their compactness and scanning speed.
Innovation Solution
An optical scanning apparatus using a multi-core fiber with a basic wavefront modulator and a condensing position control section, such as a galvano mirror, to generate and control the light spot's position for high-speed point scanning, independent of the spatial light phase modulator's frame rate, by adjusting the tilt and spherical components of the wavefront.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a distal end scanner with scanning mechanism is used for point scanning, then high-definition imaging is achieved, but the apparatus size cannot be reduced
Solution Approach 1:
The patent extracts the scanning mechanism from the distal end and relocates it to the proximal end. The distal end now only contains the objective lens and imaging sensor, while the scanning function is performed by a galvanometer mirror or MEMS device at the proximal end, eliminating the need for a bulky distal end scanner and reducing overall apparatus size.
Solution Approach 2:
The patent inverts the conventional configuration by placing the scanning mechanism at the proximal end rather than the distal end. This reversal allows the light beam to be scanned before entering the optical fiber, enabling compact distal end design while maintaining high-definition imaging capability.
2Measurement precision
If a spatial light phase modulator is used for point scanning, then high-definition imaging is achieved, but scanning speed is limited by the modulator's frame rate
Solution Approach 1:
The patent replaces the spatial light phase modulator (liquid crystal-based) with a galvanometer mirror or MEMS device for beam scanning. These mechanical scanning devices operate at much higher speeds than liquid crystal modulators, achieving scanning rates of several kHz compared to the frame-rate-limited performance of spatial light modulators.
Solution Approach 2:
The patent employs periodic scanning motion using galvanometer mirrors or MEMS devices that oscillate at high frequencies to scan the light beam across the field of view. This periodic mechanical action enables rapid sequential illumination of multiple points, achieving high scanning speeds necessary for real-time imaging.
3Loss of information
If optical fibers are bundled for image transmission, then image transmission is achieved, but resolution is limited by the number of fiber bundles
Solution Approach 1:
The patent extracts the scanning function from the fiber bundle system and implements it at the proximal end using a galvanometer mirror. This allows the use of fewer optical fibers or even a single fiber for illumination, while the scanning mechanism creates multiple illumination points sequentially, thereby achieving high resolution without requiring a large number of fiber bundles.
Solution Approach 2:
The patent changes the operational mode from simultaneous multi-point illumination through multiple fibers to sequential single-point or multi-point illumination through a scanning mechanism. This parameter change allows high-resolution imaging with fewer fibers by temporally multiplexing the illumination of different spatial points.
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 high-speed point scanning and compact image pickup without a distal end scanning mechanism, achieving high-definition imaging with improved scanning efficiency and reduced apparatus size.
Implementation Method 1
a basic wavefront modulator configured to perform spatial light phase modulation on incident light on an optical path from the light source to the first end surface, to thereby generate light having a basic wavefront
Implementation Method 2
a two-dimensional intensity distribution control apparatus configured to change the basic intensity distribution by emitting, on the optical path from the light source to the first end surface, light for causing light in which a phase distribution of the basic wavefront is controlled
Implementation Method 3
a fiber including a plurality of cores each having one or more propagation modes including a single mode or a few modes, the fiber being configured to transmit light between a first end surface and a second end surface
Implementation Method 4
a condensing position control section, such as a galvano mirror, to generate and control the light spot's position for high-speed point scanning, independent of the spatial light phase modulator's frame rate, by adjusting the tilt and spherical components of the wavefront
Data Source
AI summary
An optical scanning apparatus includes: a light source that emits light; a basic wavefront modulator that performs spatial light phase modulation on incident light on an optical path from the light source to an incident end surface of a fiber, to thereby generate light having a basic wavefront and emit the generated light, the light having the basic wavefront being to be incident on the incident end surface for obtaining, by light emitted from an emission end surface of the fiber, illumination light having a basic intensity distribution; and a two-dimensional intensity distribution control apparatus configured to change the basic intensity distribution by emitting light for causing light in which a phase distribution of the basic wavefront is controlled to be incident on the incident end surface of the fiber.