Display system for rendering a scene with multiple focal planes
Inventors
Bhagavatula, Vijayakumar • Sankaranarayanan, Aswin • Chang, Jen-Hao
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Assignees
Member
Carnegie Mellon UniversityCarnegie Mellon University is a global research institution based in Pittsburgh, Pennsylvania, recognized for interdisciplinary education, research, and innovation in science, engineering, arts, technology, and social sciences. The university leads advancements in artificial intelligence, robotics, digital health, and performing arts. Located in a technology-driven and culturally rich city, CMU powers real-world impact through research centers, industry engagement, workforce training, and initiatives that shape regional and global communities.
Carnegie Mellon University is a global research institution based in Pittsburgh, Pennsylvania, recognized for interdisciplinary education, research, and innovation in science, engineering, arts, technology, and social sciences. The university leads advancements in artificial intelligence, robotics, digital health, and performing arts. Located in a technology-driven and culturally rich city, CMU powers real-world impact through research centers, industry engagement, workforce training, and initiatives that shape regional and global communities.
Publication Number
US-12572028-B2
Publication Date
2026-03-10
Expiration Date
Abstract
A display system includes an optical element positioned in the optical path to receive light from the display module and direct the light into a field of view to display a scene. The optical element has a focal length on an optical axis of the optical element that varies in response to a control signal. A control system is programmed to generate the control signal to cause the optical element to cycle through a series of focal lengths at a frequency. Each focal length of the series corresponds to a focal plane of a series of focal planes. The control system is programmed to vary the light field from the display module to display the scene as a sequence of different image frames, the different image frames being synchronized so that each of the different image frames is presented at a corresponding one of the series of focal planes.
Core Innovation
A display system provides a variable light field along an optical path and uses an optical element positioned in the optical path to direct light from the display element into a field of view. The optical element has a focal length on an optical axis that varies in response to a control signal, and a control system generates the control signal to continuously track the focal length and cycle the optical element through a series of focal lengths, where each focal length corresponds to a focal plane in a series of focal planes.
Tracking the focal plane includes obtaining a measurement of the optical element focal length and varying the light field from the display element based on the measurement. Different image frames are synchronized with the control signal so that each image frame is triggered to be presented at a focal plane of the series of focal planes. During measuring, the control signal continuously adjusts the focal length to sweep across a range between a minimum focal length and a maximum focal length.
A corresponding method varies a light field projected from a display element according to a sequence of different image frames and directs the light field into a field of view with an optical element. The method varies the optical element focal length through a series of different focal lengths while measuring the focal length and varying the light field based on the measuring so that each image frame is presented at a plurality of the focal lengths.
Claims Coverage
The partial content includes three independent claims, covering a display system and two methods. The claims recite three main inventive features centered on a focal-length-swept optical element, measurement-based tracking of focal length, and synchronization of image frames with focal planes, including continuous sweeping between minimum and maximum focal lengths and frequency-lower cycling relative to display frame rate.
Variable light field with focal-length-swept optical element
A display system comprising a display element configured to provide a variable light field along an optical path; an optical element in the optical path that directs light into a field of view and has a focal length varying in response to a control signal; and a control system programmed to generate the control signal to continuously track the focal length and cause the optical element to cycle through a series of focal lengths, each corresponding to a focal plane.
Synchronized image frames with measured focal length
Tracking the focal plane by obtaining a measurement of the focal length of the optical element and varying the light field from the display element based on the measurement so the scene is displayed as a sequence of different image frames, with the different image frames synchronized with the control signal so each image frame is triggered to be presented at a focal plane of the series of focal planes.
Continuous focal-length sweep between minimum and maximum focal length
During measuring of the focal length, configuring the control signal to cause the optical element to continuously adjust the focal length to sweep across a range between a minimum focal length and a maximum focal length.
Displaying scene with focal-plane-multiplexed image frames
A method varying a light field projected from a display element according to a sequence of different image frames; directing the light field with an optical element into a field of view; varying a focal length of the optical element through a series of different focal lengths while measuring the focal length and varying the light field based on the measuring so that the scene is displayed by presenting each image frame at a plurality of the focal lengths; and continuously adjusting the focal length with a control signal to sweep between a minimum focal length and a maximum focal length during measuring.
Depth-of-field rendering using frequency-lower cycling and focal-plane correspondence
A method comprising determining a display frame rate; determining a set of focal planes for displaying a corresponding image frame; generating a first control signal to cycle an optical element through a range of focal lengths at a frequency lower than the display frame rate; measuring the focal length as the optical element cycles; and generating a second control signal based on the measurement to cause the display element to display the corresponding image frame when the focal length corresponds to a plurality of focal planes of the set, such that the image frame corresponds to the plurality of focal planes for the depth of field of the scene.
Across the independent claims, the central coverage is an optical element whose focal length varies under a control signal and cycles through focal planes, measurement-based tracking of focal length, and synchronization of varying image frames with the optical element’s focal plane so the scene is displayed with depth or depth-of-field effects.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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