Dual-Function Optic for Zero-Parallax AR Eye Display
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Solution Overview
Problem
Existing see-through AR displays suffer from parallax and occlusion issues due to non-coincident line-of-sight between the camera and the observer's eye, exacerbated by distance and complex environments.
Innovation Solution
A dual-function optic with a sensor camera imaging optics pipeline and virtual projection point at the eye's retina, incorporating specific coatings and surfaces to align display and camera images, eliminating parallax errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If geometric correction is used to lower display location error, then alignment accuracy is improved, but the solution fails for complex environments with occlusions and requires knowing range or pose of devices
Solution Approach 1:
The patent introduces a beamsplitter as an intermediary optical element that combines the display light path and camera light path into a single optical axis. This mediator enables both the display and camera to share the same line of sight, eliminating parallax errors without requiring complex geometric correction algorithms or knowledge of device pose and range
Solution Approach 2:
The patent merges the display optical path and camera optical path into a single coincident line of sight through the use of a beamsplitter. By combining these previously separate paths, the system achieves zero parallax error and maintains accurate alignment in complex environments with occlusions, without requiring geometric correction
2Length of moving object
If the distance between AR device and complementary camera is increased, then more space is available, but parallax errors worsen
Solution Approach 1:
The beamsplitter acts as an intermediary that allows the display and camera to share the same optical axis regardless of their physical separation. This eliminates the parallax error that would otherwise increase with greater distance between the AR device and camera
Solution Approach 2:
The patent uses optical dimensionality by introducing a beamsplitter that redirects light paths in three-dimensional space. This allows the display and camera to be positioned at different locations while maintaining coincident lines of sight through optical path folding, effectively decoupling physical distance from optical alignment
3Ease of operation
If viewing distance is decreased for better immersion, then user experience is improved, but parallax and occlusion issues worsen
Solution Approach 1:
The beamsplitter serves as an intermediary optical element that maintains precise alignment between display and camera images even at close viewing distances. This mediator ensures that both images share the same line of sight, preventing parallax errors from worsening immersion quality
Solution Approach 2:
The patent employs curved surfaces in the optical elements to control and direct light paths. The curved beamsplitter surface and optical design enable precise image alignment and maintain zero parallax error at close viewing distances, enhancing both immersion and alignment accuracy
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
Achieves zero parallax error between displayed and real-world images, enabling precise alignment and simultaneous viewing of augmented and real-world content.
Implementation Method 1
An exemplary dual-function optic of a bulk substrate material comprises an entrance surface of a bulk substrate material having a convex curvature coated with a hot mirror coating disposed as an upper surface to receive display light rays, wherein said hot mirror coating transmits a visible spectrum of said display light rays as a transmitted light beam, but reflects an infrared spectrum
Implementation Method 2
a 50% beamsplitter surface formed in the bulk substrate material at an angle of 45° to reflect roughly 50% of all wavelengths of light, including both visible and infrared, whereas light that is not reflected is transmitted as a further transmitted light
Implementation Method 3
a bottom curved surface of the bulk substrate material coated with a cold mirror coating disposed at an opposite end of the entrance surface to receive said further transmitted light of said transmitted light beam, wherein the cold mirror coating transmits an infrared spectrum but reflects the visible spectrum such that the bottom curved surface behaves as a concave mirror to reflect the visible spectrum of said further transmitted light with positive optical power
Implementation Method 4
an exterior side surface of the bulk substrate material is disposed at an opposite end of the exit portal surface of the bulk substrate material and coated with a broad-spectrum anti-reflection coating that transmits both visible and infrared spectra of a real world image incident on the exterior side surface
Data Source
AI summary
For see-through AR displays, the current state of art uses geometric correction to lower the display location error, however this is far from an ideal solution and requires knowing range or pose of the devices. A dual-function optic for eye display & camera is disclosed, wherein a sensor camera imaging optics pipeline with a virtual projection point at an eye's retina reduces parallax errors to zero.