Midair Display Light Guide Plate Deflectors
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Solution Overview
Problem
Conventional display devices projecting images in midair fail to provide a stereoscopic view and limit the range from which observers can view the image, as the virtual image is formed at an infinite distance and cannot be observed simultaneously by multiple observers at the same location.
Innovation Solution
A display device incorporating an image projection unit, a light guide plate with deflecting units, and a mask that collimates and directs light beams to specific viewpoints, allowing multiple observers to view a real, stereoscopic image from various angles by forming image points at different locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light guide plate with beam splitters is used to project an image in midair, then the image can be transmitted and made visible simultaneously with other objects, but the virtual image is formed at an infinite distance making it less stereoscopic and limiting the viewpoint range
Solution Approach 1:
The light guide plate is divided into multiple regions with different optical properties: a first region with a first refractive index and a second region with a second refractive index. This segmentation allows different portions of the light guide plate to perform different functions - one region forms the virtual image while the other forms the real image, thereby expanding the viewpoint range and improving stereoscopic effects without compromising the image transmission capability
Solution Approach 2:
Different regions of the light guide plate are assigned different local optical qualities through varying refractive indices. The first region is optimized for virtual image formation while the second region is optimized for real image formation, allowing each region to perform its specific function optimally and collectively resolving the contradiction between image transmission and viewpoint versatility
2Device complexity
If the virtual image is formed at an infinite distance, then the light guide structure can be simplified, but multiple observers cannot observe the virtual image simultaneously at an identical location
Solution Approach 1:
The light guide plate is segmented into functional regions with different refractive indices, where the second region specifically forms a real image at a finite distance. This real image can be observed by multiple observers simultaneously from the same location, enabling multi-observer capability while maintaining relatively simple light guide structure
Solution Approach 2:
The second region of the light guide plate acts as an intermediary that converts the infinite-distance virtual image into a finite-distance real image. This intermediary region with a specific refractive index enables multiple observers to view the image simultaneously without significantly complicating the overall light guide structure
3Ease of operation
If beam splitters are arranged in the light guide substrate, then image display light can be guided to the observer, but the range where a virtual image can be observed is limited to the range where the outgoing surface is provided
Solution Approach 1:
The invention extends the observable range by creating a real image in a different spatial dimension (at a finite distance in front of the light guide plate) in addition to the traditional virtual image. This dimensional extension allows observers to view the image from a broader range of positions and angles, overcoming the limitation of the outgoing surface range while maintaining the light guidance function
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 widens the range of viewpoints for observing the projected image, enabling stereoscopic viewing and allowing multiple observers to see the image simultaneously from different locations.
Implementation Method 1
a light guide plate which is formed of a transparent member and has a plate shape and includes an incident surface that faces the image projection unit, and a plurality of deflecting units
Implementation Method 2
Each of the plurality of deflecting units causes light beams to be emitted from an outgoing surface, which is one surface of the light guide plate, at angles different from each other
Implementation Method 3
The image projection unit collimates light beams emitted from the predetermined region, in the direction orthogonal to the longer direction of the incident surface of the light guide plate
Data Source
AI summary
A display device includes an image projection device, a light guide plate, and a mask. The light guide plate includes deflectors arranged in a propagation direction of a light beam emitted from the image projection device and entering the light guide plate. Each deflector causes light beams to be emitted from an outgoing surface at angles different from each other in the propagation direction, the light beams emitted from locations different from each other or emitted in directions different from each other in a direction orthogonal to the longer direction of an incident surface in a displayed region of the image projection device. The mask shuts-off light beams other than a light beam directed toward a predetermined viewpoint among light beams emitted from the outgoing surface. The image projection device collimates light beams emitted from the region, in the direction orthogonal to the longer direction of the incident surface.