Wedge Prism Optical Window for AR Headset Thickness
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Solution Overview
Problem
Existing see-through type display apparatuses face challenges in achieving a balance between a wide field of view and reduced system thickness, as the angle defined by the path conversion member's dimensions affects the wearability and reliability of head-mounted displays, particularly in augmented reality applications.
Innovation Solution
The proposed see-through type display apparatus incorporates a path conversion member with specific angle constraints (5° ≤ θ ≤ 30°) and uses a combination of hologram optical elements and polarization-selective lenses to redirect light paths, ensuring a wide field of view while minimizing system thickness, and includes a translucent concave mirror for focusing, allowing for both virtual and real environment visualization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the path conversion member uses a large angle to achieve a wide field of view, then the field of view is improved, but the system thickness increases
Solution Approach 1:
The patent applies dimensionality change by using a wedge-type prism with multiple wedged facets arranged in a third direction that forms an angle with the first direction. This three-dimensional arrangement allows the light path to be converted efficiently while maintaining a compact thickness in the second direction, thus achieving a wide field of view without increasing system thickness.
Solution Approach 2:
The path conversion member is divided into multiple wedged facets arranged in the third direction. Each facet processes light at different angles, collectively providing a wide field of view while keeping the overall thickness controlled. The segmentation of the prism into multiple facets allows for optimized light path conversion across different viewing angles.
2Length of stationary object
If the path conversion member uses a small angle to reduce system thickness, then the system thickness is reduced, but the field of view narrows
Solution Approach 1:
By introducing a third direction for arranging wedged facets, the system expands the field of view in a dimensional direction that does not increase the thickness in the second direction. This allows the path conversion member to maintain a small angle configuration for reduced thickness while still achieving a wide field of view through the multi-facet arrangement.
Solution Approach 2:
The multiple wedged facets segmented in the third direction enable the system to achieve a wide field of view through angular distribution of light paths, rather than requiring a large single angle that would increase thickness. Each facet contributes to the overall field of view while maintaining compact dimensions.
3Area of stationary object
If hologram optical elements and polarization-selective lenses are used to redirect light paths, then the field of view is improved, but the device complexity increases
Solution Approach 1:
The patent combines the path conversion function and the focusing function into an integrated optical system. The wedge-type prism handles path conversion while the translucent concave mirror handles focusing, eliminating the need for separate hologram optical elements and polarization-selective lenses. This merging of functions reduces device complexity while maintaining the wide field of view capability.
Solution Approach 2:
The patent extracts and eliminates unnecessary complex components (hologram optical elements and polarization-selective lenses) from the optical system. By using simpler components like the wedge-type prism and translucent concave mirror, the system achieves the same light path redirection and focusing functions with reduced complexity.
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 enhances the field of view and reduces the thickness of the display apparatus, improving wearability and reliability for augmented reality applications by effectively overlaying virtual information onto real-world environments.
Implementation Method 1
a path conversion member configured to change a path of light of the first image to a second direction
Implementation Method 2
the path conversion member comprises a wedge-type prism comprising a plurality of wedged facets
Implementation Method 3
a focusing member configured to focus the light of the first image in the second direction, wherein the path conversion member is configured to occupy a space according to an angle
Implementation Method 4
a focusing member configured to focus the light of the first image in the second direction
Implementation Method 5
The path conversion member comprises a first hologram optical element having a hologram pattern that is configured to change the light of the first image incident in the first direction to exit in the second direction
Implementation Method 6
The focusing member may comprise a polarization-selective lens for light having a first polarization state and having substantially no refractive power for light having a second polarization state
Implementation Method 7
a polarization-selective lens for light having a first polarization state and having substantially no refractive power for light having a second polarization state
Data Source
Figure 1~2A
Figure 2B~3
Figure 4~5
AI summary
An optical window system includes: a path conversion member configured to change a path of light of a first image from a first direction to a second direction, the path conversion member being translucent to light incident in the second direction; and a focusing member configured to focus the light of the first image in the second direction. Moreover, the path conversion member is configured to occupy a space according to an angle, defined by a first length of the path conversion member in the first direction and a second length of the path conversion member in the second direction, satisfying a predetermined condition, thereby reducing a system thickness and providing a wide field of view.