Folded Optical Module Layout for Compact HMD Image Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical modules in VR devices face challenges in achieving compactness without compromising image clarity and immersive experiences, as current approaches often limit compatibility with various screen sizes.
Innovation Solution
An optical module design featuring a folded light path structure with a lens group, polarizing element, beam splitting element, and phase retarder, where the ratio of half the display screen size to the distance from the beam splitting element to the display screen is controlled within specific ranges to ensure compactness and compatibility with different screen sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the optical module is downsized to reduce weight and spatial footprint, then the device becomes more compact, but the image clarity and immersive experiences are compromised
Solution Approach 1:
The patent employs a folded light path design that redirects light through multiple reflections off the polarizing element, effectively folding the optical path into a more compact spatial arrangement. This allows the optical module to maintain adequate optical path length for image quality while reducing the overall device volume and weight.
Solution Approach 2:
The polarizing element serves multiple functions simultaneously: it acts as a beam splitter to create the folded light path, functions as a wave plate to control polarization state, and serves as a structural component of the optical module. This multi-functionality reduces the number of separate components needed, enabling miniaturization without sacrificing optical performance.
2Volume of moving object
If the optical module is miniaturized, then the device weight and spatial footprint are reduced, but the compatibility with various screen sizes is limited
Solution Approach 1:
The patent establishes specific parameter ranges for the optical module components, particularly the distance between the display screen and polarizing element (0.05D1≤L1≤0.15D1) and the effective diameter of the polarizing element (0.7D1−0.2D1/2≤B1≤0.8D1+0.2D1/2). These parameter relationships allow the optical module to be scaled proportionally with different screen sizes while maintaining consistent optical performance and compact form factor.
3Volume of moving object
If the distance from the beam splitting element to the display screen is reduced for compactness, then the optical module becomes smaller, but the brightness uniformity across the field of view deteriorates
Solution Approach 1:
The patent applies local quality optimization by carefully positioning the polarizing element at specific distances from the display screen based on the screen size parameters. This localized parameter control ensures that the folded light path maintains appropriate geometry for achieving uniform brightness distribution across the field of view, while still enabling overall compactness of the optical module.
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 design achieves improved compactness and compatibility with various screen sizes while maintaining image quality, ensuring uniform brightness and reduced brightness differences across the field of view, enhancing user experience.
Implementation Method 1
the optical module further includes a polarizing element, a beam splitting element and a phase retarder
Implementation Method 2
the polarizing element and the beam splitting element are provided with at least one lens therebetween
Implementation Method 3
the phase retarder is located on the light-emitting side of the display screen
Implementation Method 4
a lens group located on a light-emitting side of the display screen; the lens group includes at least one lens
Data Source
AI summary
The disclosure provides an optical module and a head mounted display. The optical module includes: a display screen with a size of D1; a lens group located on a light-emitting side of the display screen; the lens group includes at least one lens; the optical module further includes a polarizing element, a beam splitting element and a phase retarder, wherein the polarizing element and the beam splitting element are provided with the at least one lens of the lens group therebetween, and the phase retarder is located on the light-emitting side of the display screen; wherein a distance from the beam splitting element to the display screen is A3, which satisfies:1<(D1/2)/A3<9.