Polarization Control Unit for AR Head-Mounted Display FOV
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Solution Overview
Problem
Current augmented reality systems using head-mounted displays face challenges in enlarging the field of view (FOV) for users without requiring multiple microdisplays, which complicates synchronization and reduces brightness due to the need for color filters in microdisplay technologies like OLEDoS.
Innovation Solution
An optical device with a single display device and a polarization control system using first and second polarizing mirrors to output and reflect images as polarized light, allowing a larger FOV without the need for multiple displays and eliminating the requirement for color filters, thereby enhancing brightness and simplifying synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple microdisplays are used to enlarge the field of view, then the field of view area is improved, but the device complexity and synchronization difficulty increase
Solution Approach 1:
The patent uses a single microdisplay and extends the field of view in the angular dimension through polarization control and mirror reflection. By switching polarization states and using polarizing mirrors at different orientations, the system projects images to different angular regions, effectively enlarging the FOV without adding multiple display devices.
Solution Approach 2:
The patent employs dynamic polarization switching to control which polarizing mirror reflects which image at different time periods. The polarization control unit dynamically changes the polarization state of light from the single microdisplay, enabling different images to be directed to different mirrors and subsequently to different angular regions, achieving FOV expansion through temporal and angular multiplexing.
2Area of stationary object
If multiple microdisplays are used to enlarge the field of view, then the field of view area is improved, but the synchronization difficulty increases
Solution Approach 1:
The patent uses periodic switching of polarization states in time-synced intervals. During first time periods, first images with first polarization are reflected by first polarizing mirrors; during second time periods, second images with second polarization are reflected by second polarizing mirrors. This periodic temporal multiplexing allows a single microdisplay to serve multiple angular regions without synchronization issues between multiple displays.
Solution Approach 2:
The system dynamically switches the polarization state of the single microdisplay output in synchronization with the display timing. By controlling when each image is displayed and its corresponding polarization state, the system achieves seamless temporal multiplexing that eliminates inter-device synchronization problems while expanding the effective FOV.
3Area of stationary object
If multiple microdisplays are used to enlarge the field of view, then the field of view area is improved, but the brightness decreases due to color filters
Solution Approach 1:
The patent makes a single microdisplay perform multiple functions by using polarization control and temporal multiplexing. The same microdisplay generates images for different angular regions and polarization states at different time periods, eliminating the need for multiple microdisplays and their associated color filters, thereby maintaining high brightness while expanding the field of view.
Solution Approach 2:
The patent changes the polarization parameter of the light output from the single microdisplay to direct images to different polarizing mirrors. By switching between first and second polarization states, the system routes different images to different angular regions without needing multiple displays, avoiding the brightness loss that would result from using multiple microdisplays with color filters.
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 optical device effectively enlarges the user's FOV while maintaining high brightness and simplifying the driving process, as it uses a single display device and polarization control to provide a unified image, improving upon the limitations of existing systems.
Implementation Method 1
a polarization control unit between the display device and the lens and outputting the display image output from the display device as first polarized light or second polarized light
Implementation Method 2
a first polarizing mirror is configured to reflect a display image of the first polarized light and transmitting a display image of the second polarized light
Implementation Method 3
a second polarizing mirror is configured to reflect a display image of the second polarized light and transmitting a display image of the first polarized light
Data Source
AI summary
A optical device includes: a display device configured to output a display image; a lens on one side of the display device; and a polarization control unit between the display device and the lens and configured to output the display image output from the display device as first polarized light or second polarized light, wherein the lens comprises: a first polarizing mirror configured to reflect a display image of the first polarized light and to transmit a display image of the second polarized light; and a second polarizing mirror configured to reflect a display image of the second polarized light and to transmit a display image of the first polarized light.