Dynamic Parallax Barrier Light Steering for Far-View 3D Displays
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Solution Overview
Problem
Existing autostereoscopy techniques struggle to provide robust and accurate stereoscopic views, especially for users located far away from the light field display unit, due to small angles between gaze vectors and the need for precise barrier adjustments at subpixel accuracy, leading to cross-talk and degraded color reproduction.
Innovation Solution
A system and method employing a parallax barrier with an active optical element that dynamically steers light based on user locations, using tracking means to determine eye positions and control the active optical element to direct light accurately towards each eye, allowing for precise light steering and high-quality virtual image presentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing autostereoscopy techniques use a static or simple dynamic parallax barrier, then the device complexity is low, but the measurement precision of user eye location and the manufacturing precision of barrier positioning deteriorate, leading to cross-talk and poor color reproduction for far-away viewers
Solution Approach 1:
The system performs preliminary eye tracking to determine the relative location of the user's eyes before generating the light field image. This preliminary action allows the system to pre-calculate the optimal barrier configuration and active optical element control parameters, ensuring high precision light steering without requiring complex real-time adjustments during image display
Solution Approach 2:
The patent introduces an active optical element as an intermediary between the light-emitting unit and the parallax barrier. This intermediary component dynamically steers light towards the detected eye locations, bridging the gap between the fixed barrier structure and the variable user position, thereby achieving high precision light direction without requiring the barrier itself to be highly complex
2Manufacturing precision
If the parallax barrier is adjusted at high precision for far-away viewers, then the autostereoscopic view quality improves, but the device complexity and control difficulty increase significantly
Solution Approach 1:
The patent replaces the traditional mechanical approach of physically moving or adjusting the parallax barrier with an optical control approach using active optical elements. Instead of mechanically repositioning barrier portions to achieve precise light steering, the system uses electrically controllable active optical elements that can dynamically adjust light direction through changes in optical properties, thereby achieving high positioning precision without complex mechanical control systems
Solution Approach 2:
The active optical element changes its optical parameters (such as refractive index or orientation) in response to detected eye locations. This parameter change allows the element to dynamically steer light towards the user's eyes without physical movement, achieving precise barrier positioning effect through optical parameter modulation rather than mechanical adjustment
3Area of stationary object
If the viewing distance increases beyond 1 meter, then the user comfort and viewing area improve, but the angle between gaze vectors becomes exceedingly small, causing existing techniques to fail in providing robust autostereoscopy
Solution Approach 1:
The system creates a computational model (copy) of the light field that accounts for the small gaze vector angles at large viewing distances. By generating a light field image specifically tailored to these angular conditions and using eye tracking to detect the precise relative eye locations, the system can accurately reproduce the intended stereoscopic effect even when the physical angles are exceedingly small, effectively copying the ideal viewing geometry into the computational model
4Adaptability or versatility
If a dynamic parallax barrier using LC layer is used, then the adaptability to different viewing conditions improves, but the resolution of the LC layer limits the granularity of control, causing cross-talk and color degradation for far-away viewers
Solution Approach 1:
The patent segments the light control function between the parallax barrier (which provides the basic optical routing structure) and the active optical element (which provides fine-grained dynamic control). This segmentation allows the LC layer to handle adaptability to different viewing conditions while the active optical element compensates for the limited granularity by providing additional precision in light steering through higher resolution or more responsive control mechanisms
Solution Approach 2:
The system dynamically adjusts the active optical element based on real-time eye tracking data to compensate for the fixed granularity of the LC layer. This dynamic adjustment allows the system to adapt to different viewing conditions and user positions, effectively overcoming the resolution limitations of the LC layer by adding a layer of dynamic control that can make fine adjustments beyond the static LC barrier capabilities
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 high-quality, accurate, and computationally-efficient autostereoscopic views for users, even at distances greater than 1 meter away, by dynamically controlling the active optical element to align light directions with user gaze vectors, reducing cross-talk and enhancing color reproduction.
Implementation Method 1
controlling the active optical element, based on the relative location of the first eye and of a second eye of at least one user, to direct light corresponding to a first set of photo-emitting cells towards the first eye and light corresponding to a second set of photo-emitting cells towards the second eye
Implementation Method 2
The opaque portions selectively block light emanating from certain pixels of the light field display unit in certain directions, while the transparent portions allow said light to pass through in certain other directions
Data Source
AI summary
A light field image is displayed via a light field display unit to produce a synthetic light field. A first viewing direction and a second viewing direction are determined for a given first photo-emitting cell and a given second photo-emitting cell of the light field display unit, based on a relative location of a first eye and a second eye with respect to an image plane of the light field display unit, respectively. A given first portion and a given second portion of an active optical element that lie respectively on optical paths of the given first photo-emitting cell and the given second photo-emitting cell are controlled, to direct light corresponding to the given first photo-emitting cell and light corresponding to the given second photo-emitting cell along the first viewing direction and the second viewing direction, respectively.