Near-Eye Display Optics Using Polarized Light Splitting to Eliminate Ghosting
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Solution Overview
Problem
Existing near-eye display optical systems suffer from low light efficiency and ghosting issues due to the use of plate glass with transflective films, leading to significant light loss and double images.
Innovation Solution
A near-eye display device incorporating a polarizer, phase delay layers, a polarized light splitter, and a curved mirror to convert and reflect light efficiently, reducing energy loss and eliminating ghosting by utilizing polarized light states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If plate glass with transflective film is used to refract and reflect light, then the optical system can be compact, but light efficiency is reduced due to energy loss
Solution Approach 1:
The patent changes the optical parameters by replacing the transflective film on plate glass with a polarized light splitter that utilizes polarization state changes. The system employs a polarizer to convert light into linearly polarized light, then uses a quarter-wave plate to convert it to circularly polarized light, and finally uses the polarized light splitter to reflect or transmit based on polarization orientation, achieving high light efficiency without energy loss from traditional transflective films
Solution Approach 2:
The patent uses a composite optical system comprising multiple functional layers: a polarizer layer, a quarter-wave plate layer, and a polarized light splitter layer. These composite optical elements work together to manipulate light polarization states, enabling the system to achieve both compact form factor and high light efficiency by controlling light through polarization rather than relying on energy-lossy transflective coatings
2Device complexity
If plate glass with transflective film is used to reflect light, then the optical path can be folded, but ghosting occurs due to double reflection on upper and lower surfaces
Solution Approach 1:
The patent eliminates ghosting by changing the reflection mechanism from surface reflection (which causes double images from upper and lower surfaces) to polarization-based reflection. The polarized light splitter reflects light based on its polarization orientation rather than surface geometry, ensuring that only a single reflected image is produced while still enabling optical path folding for compact design
Solution Approach 2:
The patent introduces a polarizer and quarter-wave plate as intermediary elements between the light source and the reflecting surface. These intermediaries convert the light into circularly polarized light before it reaches the polarized light splitter, ensuring that the reflection occurs based on polarization state rather than surface reflection, thereby eliminating ghosting while maintaining the ability to fold the optical path
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 light efficiency and eliminates ghosting, providing improved visual quality and compactness by optimizing the optical system's design.
Implementation Method 1
a polarizer, positioned on the light outgoing side of the display device, and configured to convert light emitted from the display device into first linearly polarized light
Implementation Method 2
a first phase delay layer, positioned on a side of the polarizer distal to the display device, and configured to convert the first linearly polarized light transmitted by the polarizer into circularly polarized light
Implementation Method 3
a polarized light splitter, positioned on a side of the first phase delay layer distal to the polarizer, obliquely arranged relative to the polarizer, and configured to transmit the first linearly polarized light and reflect a second linearly polarized light with a polarization direction perpendicular to a polarization direction of the first linearly polarized light
Implementation Method 4
a second phase delay layer, positioned on a side of the polarized light splitter proximal to the first phase delay layer, and configured to convert the circularly polarized light transmitted by the first phase delay layer into the second linearly polarized light or partially polarized light including the second linearly polarized light
Implementation Method 5
a curved mirror, positioned on a reflected light path of the polarized light splitter and on a side of the second phase delay layer distal to the polarized light splitter, and configured to partially reflect the circularly polarized light or the elliptically polarized light converted by the second phase delay layer again to a position of a human eye and partially transmit ambient light
Data Source
AI summary
A near-eye display device, including: a display device (1) for displaying an image; an imaging lens (2) on a light-outgoing side of the display device (1) and for imaging the image displayed on the display device (1); a polarizer (3) on the light-outgoing side and for converting light emitted from the display device (1) into linearly polarized light; first and second phase delay layers (41,42), on a side of the polarizer (3) distal to the display device (1) and for converting a polarization state of incident light; a polarized light splitter (5) on a side of the second phase delay layer (42) distal to the polarizer (3); and a curved mirror (6) on a reflected light path of the polarized light splitter (5) and for partially reflecting light transmitted by the second phase delay layer (42) to human eyes and partially transmitting ambient light.