Curved Beam Splitter Display for Thin Aerial Image Formation
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Solution Overview
Problem
Existing display devices face challenges in achieving thinness while maintaining the height at which an aerial image forms, and higher-order aerial images are generated due to specularly reflected light components causing multiple reflections.
Innovation Solution
The use of a display device with a polarized-beam splitter having a curved surface and a retroreflective member arranged to face the concave side, along with a diffuser and polarizing plate, reduces the device thickness and minimizes higher-order aerial image visibility by adjusting the angles of incidence and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a flat beam splitter is used in the display device, then the device structure is simple, but the aerial image forms at a fixed height that cannot be increased without increasing device thickness
Solution Approach 1:
The patent applies a curved surface beam splitter instead of a flat beam splitter. The curved surface modifies the optical path of reflected light, enabling the aerial image to form at a greater floating distance while keeping the device thickness reduced. This curvature transformation is the key innovation that resolves the contradiction between increasing image height and maintaining thin device profile.
2Length of moving object
If the beam splitter surface is curved, then the floating distance of the aerial image is increased, but the manufacturing complexity increases
Solution Approach 1:
The patent specifies that the beam splitter has a curved surface with a particular radius of curvature (R = 500mm in the embodiment). This defined curvature parameter provides a manufacturable solution that achieves the desired optical effect while maintaining reasonable manufacturing feasibility through standard optical fabrication techniques.
3Length of moving object
If the retroreflective member is positioned to maximize aerial image height, then higher-order aerial images are generated due to specularly reflected light components
Solution Approach 1:
The patent positions the retroreflective member asymmetrically relative to the beam splitter, with its surface normal not aligned with the optical axis. This asymmetric arrangement, combined with the curved beam splitter surface, directs specularly reflected light away from the observation region, thereby suppressing the formation of harmful higher-order aerial images while maintaining the desired primary aerial image height.
Solution Approach 2:
The patent effectively extracts or removes the harmful specularly reflected light components from the observation path by strategic positioning of the retroreflective member and utilizing the curved beam splitter to redirect these components away from the viewer's field of view.
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 allows for a thinner display device with increased floating distance of the aerial image and reduced visibility of higher-order images, enhancing the display's effectiveness.
Implementation Method 1
a retroreflective member for retroreflecting light representing a design to generate light representing the design
Implementation Method 2
a beam splitter having a curved surface... The beam splitter is a polarized-beam splitter
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A display device capable of displaying an aerial image by using retroreflection is provided. The display device includes: a generator configured to generate light representing a design of the aerial image as an original image; a retroreflective member configured to retroreflect the light representing the design; and a beam splitter including a curved surface, wherein the beam splitter is disposed such that a concave side thereof faces the retroreflective member.