Scanning Projector MEMS Scanner Speckle Reduction
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Solution Overview
Problem
Current display methods for shelf information, such as paper price tags and Electronic Shelf Labels (ESLs), are limited in their ability to provide high-quality, dynamic, and large-scale visual information with low power consumption and are prone to errors and high maintenance costs.
Innovation Solution
A scanning projector using a Micro-Electro-Mechanical-System (MEMS) scanner is integrated into a shelf display module to project high-quality images and information onto a screen, reducing speckle, improving heat dissipation, and offering a compact design, while allowing for low-power operation and easy assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a scanning projector using MEMS scanner is used to display large-scale information, then the display area and information quality are improved, but the device complexity and heat generation increase
Solution Approach 1:
The patent integrates multiple optical components (laser light source, collimating lens, scanning mirrors, projection lens) into a compact nested structure where components are arranged in sequence within a confined space. The MEMS scanner is integrated within the optical engine assembly, and the entire projector unit is housed within a compact casing that contains heat dissipation structures, achieving space-efficient nesting of functional elements.
Solution Approach 2:
The optical engine assembly serves multiple functions: it generates laser light, collimates the beam, scans the light horizontally and vertically, focuses the scanned light, and projects the final image. The housing structure simultaneously provides mechanical support, thermal management through integrated heat sinks, and optical alignment references, reducing the need for separate dedicated components.
2Illumination intensity
If laser light source is used in the scanning projector, then the brightness and image quality are improved, but speckle noise and heat generation increase
Solution Approach 1:
The patent employs rapid oscillation of the MEMS scanning mirrors at frequencies above the human visual system's temporal resolution. The mirrors perform high-frequency horizontal and vertical scanning movements, creating a persistent visual image through temporal integration. This periodic motion at controlled frequencies reduces the visibility of speckle patterns by averaging them over time, while maintaining bright, stable image output.
3Manufacturing precision
If multiple optical components are integrated for scanning and projection, then the image quality is improved, but the assembly complexity and manufacturing difficulty increase
Solution Approach 1:
The patent divides the projector into distinct modular segments: the optical engine module containing light generation and scanning components, the projection lens assembly, the heat dissipation module with heat sinks, and the housing structure. Each module can be independently manufactured, tested, and assembled, reducing overall manufacturing complexity while maintaining precise optical alignments through standardized mounting interfaces and alignment features.
4Volume of moving object
If a compact design is implemented, then the device size is reduced, but heat dissipation becomes more difficult
Solution Approach 1:
The patent implements localized heat dissipation structures positioned in immediate proximity to heat-generating components. Heat sinks with extended surface areas are directly coupled to laser diode mounts and scanning mirror assemblies, creating localized thermal management zones. Thermal vias and heat conduits are strategically placed in the housing structure to channel heat from compact internal components to external dissipation surfaces, enabling effective heat management within a reduced overall device volume.
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
The solution enables the display of detailed product information, including prices and videos, on a large scale with reduced speckle, efficient heat management, and a compact design, addressing the limitations of existing methods with improved image quality and reduced maintenance costs.
Implementation Method 1
a scanner that scans the light output from the light source unit in horizontal and vertical directions based on the light output from the light source unit
Implementation Method 2
a light synthesizer that synthesizes light beams output from the plurality of mirrors
Implementation Method 3
Each of the collimating lenses collimates laser light output from a corresponding laser light source
Implementation Method 4
The scanning projector projects light on a screen in an accommodation space of the lower case
Data Source
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AI summary
A scanning projector including a light source unit including a plurality of laser light sources; a mirror unit including a plurality of mirrors which transmit or reflect light beams output from the light source unit; a light synthesizer which synthesizes the light beams transmitted or reflected by the mirror unit; a Micro-Electro-Mechanical-System (MEMS) scanner which reflects incident light and performs scanning of the light in a horizontal direction and a vertical direction; and a light reflection unit which reflects light, having passed through the light synthesizer, to the MEMS scanner. Further, the light synthesizer includes a 1/2 wavelength plate converting a first polarization of the light beams transmitted or reflected by the mirror unit into a second polarization, and a Polarization Beam Splitter (PBS) surface synthesizing the light beams polarization-converted by the 1/2 wavelength plate into the second polarization with the light beams having the first polarization.