Pancake Optical Display Layout for Chromatic Aberration Control
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Solution Overview
Problem
Conventional optical display systems in virtual reality devices suffer from chromatic aberration and stray light, which degrade image quality and viewing experience, particularly in immersive head-mounted displays.
Innovation Solution
Incorporating a reflection-type Pancharatnam-Berry lens operating in the Bragg regime, along with refractive lenses for chromatic aberration correction, to selectively reflect and transmit polarized light, thereby reducing chromatic dispersion and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pancake lens display assembly with reflective polarizer and quarter-wave plate is used, then circular polarization is achieved, but chromatic aberration and ghost images occur due to wavelength-dependent focal length
Solution Approach 1:
The patent changes the polarization state parameter from circular to linear by removing the quarter-wave plate, and modifies the reflective polarizer to a partial reflector that transmits one polarization and reflects the other. This parameter change eliminates the wavelength-dependent phase delay that causes chromatic aberration in conventional designs.
Solution Approach 2:
The patent extracts and removes the quarter-wave plate from the conventional pancake lens assembly. This extraction eliminates the source of wavelength-dependent phase modulation while preserving the essential polarization-selective reflection function through the modified partial reflector and reflective polarizer combination.
2Reliability
If a reflective polarizer and quarter-wave plate are used to achieve circular polarization, then the optical system provides immersive VR experience, but stray light and ghost images reduce image quality
Solution Approach 1:
The patent converts the potentially harmful effect of multiple reflections into a beneficial polarization-selective filtering mechanism. By using a partial reflector that transmits one polarization state and reflects another, the system eliminates ghost images caused by unwanted reflections while maintaining the desired optical path for the correct polarization state.
3Volume of moving object
If the optical path is tripled between partially reflective surface and reflective polarizer, then compact size is achieved, but only 25% of polarized display light enters viewer's eyes
Solution Approach 1:
The patent makes the optical system multi-functional by designing the partial reflector to simultaneously achieve compact folding of the optical path and improved light transmission efficiency. The system maintains the tripled optical path for compactness while the modified polarization-selective architecture ensures higher percentage of display light reaches the viewer compared to conventional designs.
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 proposed solution effectively reduces chromatic aberration and enhances image quality by minimizing lateral color shift and ghost images, providing a superior viewing experience.
Implementation Method 1
a reflection-type Pancharatnam-Berry lens, which is placed after the first optic unit and works in the Bragg regime, and which reflects the image light of the first polarization and transmits the image light of the second polarization
Implementation Method 2
reflection-type Pancharatnam-Berry lens, which is placed after the first optic unit and works in the Bragg regime
Implementation Method 3
a partial reflector, which transmits the image light without changing its polarization and reflects the image light with its polarization being changed to a second polarization
Implementation Method 4
a first optic unit, placed after the partial reflector, which includes at least one refractive lens for chromatic aberration correction
Implementation Method 5
Due to the wavelength-dependent focal length of the viewing optics, this visual artifact is called chromatic aberration (CA), which results from the dispersion characteristics of the dielectric constant
Data Source
AI summary
An optical display system and an electronics device are disclosed. The optical display system comprises: a display, which generating image light of a first polarization; a partial reflector, which transmits the image light without changing its polarization and reflects the image light with its polarization being changed to a second polarization; a first optic unit, placed after the partial reflector, which includes at least one refractive lens for chromatic aberration correction; and a reflection-type Pancharatnam-Berry lens, which is placed after the first optic unit and works in the Bragg regime, and which reflects the image light of the first polarization and transmits the image light of the second polarization.