Apple exploring interactive, glasses-free 3D holographic displays

The U.S. Patent and Trademark Office this week revealed a new patent application from Apple. Originally filed on Jan. 14 of 2010, the application entitled "Three-Dimensional Display System" describes a projection screen with an "angularly responsive reflective surface."

The 18-page filing is very similar to another 25-page filing discovered by AppleInsider in 2008. But in addition to advanced 3D technology, Apple's latest filing describes a new and advanced method of multi-touch input, through manipulation of three-dimensional holograms that can be touched by a user.

The new application notes that while 3D has been popular at various points over many years, it usually falls out of favor because users are not interested in wearing the eyewear that is often required to render a three-dimensional image for the viewer.

"While these approaches have been generally successful," the application says, "they have not met with widespread acceptance because observers generally do not like to wear equipment over their eyes. In addition, such approaches are impractical, and essentially unworkable, for projecting a 3D image to one or more casual passerby, to a group of collaborators, or to an entire audience such as when individual projects are desired. Even when identical projections are presented, such situations have required different and relatively undeveloped technologies, such as conventional autostereoscopic displays."

The described invention is a display system that delivers a 3D picture and interactive interface without the need for headgear or glasses. It provides two embodiments: one of a traditional stereoscopic 3D display, while another describes a "realistic holographic 3D display experience."

"The positions of one or more observers are also tracked in real time so that the images that are being projected to the observers can be continually customized to each observer individually," the application reads. "The real time positional tracking of the observer(s) also enables 3D images having a realistic vertical as well as horizontal parallax."

It continues: "In addition, each 3D image can be adjusted according to the observers' individually changing viewing positions, thereby enabling personally customized and individuated 3D images to be viewed in a dynamic and changeable environment. Further, the positional tracking and positionally responsive image adjustment enable synthetization of true holographic viewing experiences."

The application states that the invention would need a number of "building blocks" for it to work, including:

• A two-dimensional projector, including analog mirrors, a polygon scanner or similar device, and driver circuitry.
• A 3D imager (which may be part of the 2D projector).
• A projection screen having a surface function.
• A display interface.
• A digital signal processor.
• A host central processing unit with 3D rendering capability.

The described 3D display is accomplished by a screen deflecting images into observers' respective left and right eyes. An advanced camera system would sync with the projection system, ensuring that the light beam for the left and right images would correctly reach the observer's respective left and right eyes.

The application also describes an "unobtrusive 3D virtual desktop" which would allow users to "manipulate objects within the desktop by reaching into the virtual display" and "grasping" and "pushing" the objects. It describes a new form of interacting with a computer, this time accomplishing multi-touch with projected objects in a 3D space.

"The manipulation of the virtual objects occurs because the feedback mechanism recognizes observer movements, such as finger movements, at the locations of the virtual objects and reconfigures the display of the virtual objects in response," it states.

The invention of a "Three-Dimensional Display System" is credited to Christoph H. Krah, who was also credited with multi-touch applications related to tactile keyboards and computer mice for Apple.