Switchable Quarter-Wave Plate Display for Monocular Multi-Depth-of-Field VR
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Solution Overview
Problem
Conventional VR devices typically provide stereo images with a single depth of field, limiting the immersive experience by not allowing users to see multiple depths simultaneously.
Innovation Solution
A display system utilizing switchable quarter wave plates and a reflective polarizer, combined with lenses and half mirrors, to generate multiple focal distances and virtual image distances through time division multiplexing of 2D image sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional binocular parallax 3D display is used, then stereo images can be generated, but only a single depth of field is provided
Solution Approach 1:
The patent employs switchable wave plates (first and second quarter wave plates) that can dynamically change their optical states through voltage control. These wave plates switch among multiple optical states at high frequency, enabling dynamic adjustment of focal distances and virtual image distances to achieve multi-depth-of-field display
Solution Approach 2:
The patent uses time division multiplexing with periodic switching of the wave plates. The 2D image sources display different information at different moments, and the wave plates switch optical states periodically to generate multiple virtual image distances, allowing users to perceive images at different depths through temporal multiplexing
2Adaptability or versatility
If switchable wave plates are used to generate multiple focal distances, then monocular multi-depth-of-field display is achieved, but device complexity increases
Solution Approach 1:
The switchable wave plates serve multiple functions: they act as quarter wave plates in different optical states, function as focal length adjusters, and enable time division multiplexing. The same optical components (wave plates, lenses, half mirrors, reflective polarizer) are used to achieve both 2D and 3D display modes as well as multiple depth of field effects
Solution Approach 2:
The patent changes the optical parameters of the wave plates by applying different voltages to switch among multiple optical states. This parameter change approach allows the same physical components to produce different focal distances and virtual image distances without requiring multiple separate optical paths or components
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
Enables a monocular multi-depth-of-field VR display, enhancing the immersive experience by allowing users to see multiple depths of field simultaneously, improving image quality and depth perception.
Implementation Method 1
a first switchable quarter wave plate, a first lens, a half mirror, a second switchable quarter wave plate, and a reflective polarizer... both the first quarter wave plate and the second quarter wave plate have electrodes. The first quarter wave plate is driven at a first voltage and the second quarter wave plate is driven at a second voltage
Implementation Method 2
a linear polarizer is attached to the display module and configured to generate linearly polarized light
Implementation Method 3
a first lens, a half mirror, a second switchable quarter wave plate, and a reflective polarizer
Data Source
AI summary
A display system includes a display module configured to emit light, where a linear polarizer is attached to the display module and configured to generate linearly polarized light. In a light path from the display module to an eye, the display system further includes a first switchable quarter wave plate, a first lens, a half mirror, a second switchable quarter wave plate, and a reflective polarizer. The first quarter wave plate is driven at a first voltage and the second quarter wave plate is driven at a second voltage, so that the display system generates an image at a first depth of field; the first quarter wave plate is driven at the first voltage and the second quarter wave plate is driven at a third voltage, so that the display system generates an image at a second depth of field different from the first depth of field.