AR Head-Mounted Display Pupil Steering Projector
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Solution Overview
Problem
Conventional head-mounted displays are limited by their size and weight, leading to reduced brightness of projected images due to the need for high intensity light sources, which are large and heavy, and have high power consumption.
Innovation Solution
A head-mounted display device that uses an eye tracker to determine the pupil position and projects images over a reduced area, eliminating the need for high intensity light sources by directing the light precisely towards the pupil using a beam steerer and combiner, such as a Fresnel or pancake combiner, to enhance brightness and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If images are projected over a large area to provide wide field of view, then field of view is improved, but brightness of projected images deteriorates
Solution Approach 1:
The system performs preliminary eye tracking to determine pupil position before projecting images. This allows the projector to pre-position the light beam at the correct location, eliminating the need to project over a large area and thereby maintaining brightness while providing adequate field of view through sequential tracking.
Solution Approach 2:
The head-mounted display dynamically adjusts the projection area based on real-time pupil position feedback from the eye tracker. Instead of using a static large projection area, the system continuously adapts the beam direction and target area to match the user's gaze, maintaining brightness while enabling wide field of view through dynamic repositioning.
2Illumination intensity
If high intensity light sources are used to compensate for reduced brightness, then brightness is improved, but device weight and size deteriorate
Solution Approach 1:
The eye tracker performs preliminary measurement of pupil position before the projector activates. This preliminary action allows the system to direct light precisely where needed from the start, eliminating waste and enabling the use of lower intensity light sources that are smaller and lighter, while still achieving sufficient brightness at the target location.
Solution Approach 2:
Instead of illuminating a large area uniformly, the system concentrates light intensity locally at the pupil position. This local quality approach allows the use of lower overall power light sources that deliver high intensity only where needed, reducing the size and weight of the light source while maintaining brightness at the target.
3Illumination intensity
If high intensity light sources are used to compensate for reduced brightness, then brightness is improved, but power consumption deteriorates
Solution Approach 1:
The system performs preliminary eye tracking to determine the exact pupil position before projecting light. This preliminary measurement enables the projector to activate only when and where needed, directing light precisely at the pupil. This eliminates unnecessary illumination and allows the use of lower power light sources that consume less energy while maintaining sufficient brightness.
Solution Approach 2:
The system concentrates light delivery to a small local area (the pupil) rather than illuminating a large area. This local quality approach dramatically reduces the total energy required, as the light source only needs to provide sufficient intensity at the small target area, resulting in lower power consumption while maintaining brightness where it matters.
4Illumination intensity
If images are projected over a reduced area toward the pupil, then brightness is improved, but field of view deteriorates
Solution Approach 1:
The system dynamically adjusts the projection area and beam direction based on real-time pupil tracking. By continuously adapting the projection target to follow the user's gaze, the system maintains a small concentrated projection area for brightness while effectively providing a wide field of view as the small area moves across the user's visual field.
Solution Approach 2:
The eye tracker performs preliminary determination of pupil position before the projector directs the beam. This preliminary action ensures that the reduced projection area is always positioned correctly at the pupil, maintaining brightness while the tracking system enables the reduced area to cover a wide effective field of view as the user moves their eyes.
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 solution results in compact, lightweight, and low-power head-mounted displays that provide improved brightness and efficiency for augmented and virtual reality applications.
Implementation Method 1
the beam steerer is configured to change a direction of the light from the light projector based on the position of the pupil
Implementation Method 2
the combiner is configured to combine the light from the light projector and light from an outside of the head-mounted display device for providing an overlap of the rendered image and a real image
Data Source
AI summary
A head-mounted display device for providing images to a wearer includes a focus-supporting light projector and a beam steerer. The focus-supporting light projector is configured to project light for rendering images based at least on virtual reality contents and/or augmented reality contents. The light projected from the focus-supporting light projector corresponds to an image plane that is selected based at least in part on a position of a pupil of an eye of the wearer. The beam steerer is configured to change a path of the light projected from the focus-supporting light projector based on the position of the pupil of the eye of the wearer.