Scanning Device Beam Waist and Angle Synchronization
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Solution Overview
Problem
Existing scanning-type image display devices face challenges in maintaining a large scanning range while ensuring a high-definition image is in focus throughout the screen, due to difficulties in independently controlling beam waist adjustment and scan angle adjustment, leading to impaired image projection with varying projection distances.
Innovation Solution
A scanning device comprising a beam condensing unit, a beam diverging unit, and a first scanning unit, where at least one of the beam condensing unit and beam diverging unit is moved along their respective optical axes to adjust the scan angle, allowing for a larger scanning range and maintaining image focus across the entire screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the scan angle of the scanning unit is increased to achieve a large scanning range on the projection plane, then the scanning range is improved, but the driving current of the actuator increases leading to large power consumption
Solution Approach 1:
The patent divides the optical system into separate functional units: a scanning unit for angular deflection and a beam expanding unit for magnification. This segmentation allows the scanning unit to operate at optimal angles while the beam expanding unit handles the magnification, reducing the power consumption of the actuator while maintaining large scanning range.
Solution Approach 2:
The patent transitions from direct angular scanning to beam expansion in a different dimension. Instead of increasing the scan angle directly, the system uses a beam expanding unit to magnify the scanned beam, achieving large scanning range through dimensional transformation rather than angular increase.
2Area of stationary object
If the scan angle of the resonance-type micromechanical mirror is increased to achieve large scanning range, then the scanning range is improved, but the durability of the device decreases due to risk of hinge member breaking
Solution Approach 1:
The patent separates the scanning function from the beam expansion function. The resonance-type micromechanical mirror handles only angular deflection at safe angles, while the beam expanding unit (using lenses or mirrors) provides the magnification. This segmentation protects the hinge member from excessive stress while achieving large scanning range.
Solution Approach 2:
The beam expanding unit acts as an intermediary between the scanning unit and the projection plane. It takes the moderately angled scanned beam and expands it to achieve large scanning range without requiring the mirror to operate at dangerous angles, thus protecting the hinge member.
3Device complexity
If a planar image display element is used to project images, then the device structure is simplified, but reducing the size of the device becomes difficult
Solution Approach 1:
The patent replaces the traditional planar image display element (liquid crystal panel) with a scanning-based optical system. Instead of using a large physical display panel, the system uses scanned laser beams to project images, eliminating the need for bulky planar display elements while maintaining structural simplicity through optical components.
4Device complexity
If incoherent light from a lamp is used as the light source, then the device structure is simplified, but the brightness of the display image becomes low and electricity consumption becomes great
Solution Approach 1:
The patent changes the fundamental parameter of the light source from incoherent broadband light to coherent laser light. This parameter change enables high brightness and low power consumption while maintaining relatively simple device structure. The laser light's coherence and directionality naturally provide high illumination intensity without requiring complex light management systems.
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 larger scanning range on the projection plane while ensuring a high-definition image is in focus throughout, by adjusting the beam waist and scan angle in synchronization, thereby improving the image display device's performance.
Implementation Method 1
a beam condensing unit (1) that condenses the beam emitted from the light source
Implementation Method 2
a beam diverging unit (3) that is arranged on an output side of the beam condensing unit (1), and diverges the beam condensed by the beam condensing unit (1)
Data Source
AI summary
A scanning device that scans a beam emitted from a light source, includes: a beam condensing unit that condenses the beam emitted from the light source; a beam diverging unit that is arranged on an output side of the beam condensing unit, and diverges the beam condensed by the beam condensing unit; a first scanning unit that is arranged between the beam condensing unit and the beam diverging unit, and scans the beam condensed by the beam condensing unit; and a moving unit that moves at least one of the beam condensing unit and the beam diverging unit along respective optical axis directions thereof, in accordance with a scan angle of the first scanning unit.