Scattering Region Polarization Separation Lens Virtual Image Display
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Solution Overview
Problem
Existing see-through type virtual image display devices suffer from low see-through transmittance near the center of the visual field due to the processing of ambient light on the light-emitting region of the light-guiding plate, requiring additional optical systems for high transmittance, which increases device size.
Innovation Solution
A virtual image display device incorporating a scattering member with a scattering region, a projection optical system, a light-blocking member, a first polarizing member to restrict image light to a specific polarization direction, a second polarizing member to restrict external light to a different polarization direction, and a polarization separation lens element with refractive power to selectively act on polarized light, allowing for improved see-through transmittance without increasing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If processing such as formation of dots and application of a scattering material is performed on the light-emitting region of the light-guiding plate, then image light can be scattered to achieve virtual image display, but see-through transmittance decreases in the vicinity of the center of the visual field
Solution Approach 1:
The patent divides the display region into image display region and transparent display region, and further segments the light-guiding plate into light-emitting region and light-transmitting region. This segmentation allows different regions to serve different functions: the light-emitting region scatters image light while the light-transmitting region maintains high transparency for ambient light, thereby resolving the contradiction between virtual image display functionality and see-through transmittance.
Solution Approach 2:
The patent applies different optical properties to different regions of the light-guiding plate. The light-emitting region has scattering properties to direct image light, while the light-transmitting region has high transparency to allow ambient light passage. This local differentiation of optical quality enables simultaneous achievement of virtual image display and high see-through transmittance in different visual field regions.
2Illumination intensity
If an optical system with high see-through transmittance is separately required to achieve high see-through transmittance in the vicinity of the center of the visual field, then see-through display performance improves, but device size increases
Solution Approach 1:
The patent merges the functions of image light scattering and ambient light transmission into a single integrated light-guiding plate structure. By combining the light-emitting region with scattering properties and the light-transmitting region with high transparency in one component, the system achieves high see-through transmittance without requiring separate optical systems, thereby preventing device size increase.
Solution Approach 2:
The light-guiding plate is designed with multi-functionality: it simultaneously serves as an image light guiding path, a scattering element for virtual image formation, and a transparent window for ambient light transmission. This universal component performs multiple functions that would traditionally require separate optical elements, maintaining compact device size while achieving high see-through transmittance.
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 enhances see-through transmittance by selectively scattering and polarizing image and external light, enabling a more compact and efficient virtual image display device with improved visual recognition of both virtual and external images.
Implementation Method 1
a scattering member including a scattering region for scattering image light as a pixel display region
Implementation Method 2
a first polarizing member arranged at a face side of the scattering member and including a first polarizing region provided corresponding to the scattering region, the first polarizing region being configured to restrict the image light scattered by the scattering member to a first polarization direction
Implementation Method 3
a second polarizing member arranged at an external side of a position of the first polarizing member and including a second polarizing region configured to restrict the external light to a second polarization direction different from the first polarization direction
Implementation Method 4
a polarization separation lens element arranged at a face side of the first polarizing member and having refractive power configured to selectively act on polarized light of the image light
Data Source
AI summary
A virtual image display device includes: a scattering member including a scattering region for scattering image light as a pixel display region, a projection optical system configured to irradiate the scattering region with the image light, a light-blocking member arranged at an external side of the scattering member and configured to suppress incidence of external light on the scattering region, a first polarizing member arranged at a face side of the scattering member and including a first polarizing region provided corresponding to the scattering region, a second polarizing member arranged at an external side of a position of the first polarizing member and including a second polarizing region for restricting the external light to a second polarization direction, and a polarization separation lens element arranged at a face side of the first polarizing member and having refractive power that selectively acts on polarized light of the image light.