Earlier this month the US Patent & Trademark Office published a patent application from Microsoft that reveals a new transparent display system for devices such as a notebook, smartphone or other (mobile) devices. In the larger scope of things, Microsoft's invention covers a projection-type display that is used in conjunction with a relatively transparent holographic optical element (HOE) to provide a display to the user. The new display would allow the user to better view content in daylight. The technology could be used in a heads-up display.
Microsoft's Patent Background
Today's typical mobile devices have several noticeable shortcomings. Many mobile devices may be difficult to use in bright sunlit environments because the display screens are relatively dim due in part to the fact that only a very small fraction of the light emitted by the display reaches the eye of the operator of the mobile device (i.e., the human operator's eye) coupled with the large amount of battery power used for the brightness of even relatively dim displays. Additionally, because mobile devices are used in public environments where third parties may eavesdrop and see sensitive information on the screen of the mobile device, these mobile devices present certain inherent privacy concerns. In addition, current mobile devices provide only limited "augmented reality" applications for integrating mobile device capabilities specific to their location and environment.
Microsoft Invents a Projection Type of Display for Mobile Devices
Microsoft's invention generally relates to various implementations of a projection-type of display device that may be connectively coupled to a mobile device where the light generated by a small projection device is directed at a transparent holographic optical element (HOE) to provide a user display.
Depending on the implementation, the HOE may be transparent, partially transparent, or semi-transparent. In some implementations, the projector and the HOE may be configured to produce and magnify a virtual image that is perceived as being displayed at a large distance from the viewer of the image through the HOE.
In some implementations, the HOE may comprise a volume grating effective at only the narrow wavelengths of the projection device to maximize transparency while also maximizing the light reflected from the display projector to the human operator's eye.
Some implementations may comprise "augmented reality" applications that produce a virtual image that, when projected at infinity, appears in the space beyond the mobile device and superimposed on the "real world" (as opposed to a real image in the plane of the display surface).
For such implementations, the mobile device may be used with pointing and telestration applications including but not limited to use as a portable head-up display for an operator of the mobile device.
Theoretically the technology could be applied to a future Xbox headset application much like Oculus. Although Microsoft mentions a heads-up display as noted above, the emphasis of the patent is for the notebook (and smartphone).
Microsoft's New Technology Applied to Notebooks
Microsoft's patent FIG. 2 is a side view of a notebook comprising a an input device and/or an embedded display screen # 214 commonplace in many mobile devices. The display device # 200 could be used as an auxiliary or extra display in addition to a conventional display that is activated by changing the transparent cover to the vertical viewing position.
The mobile base # 210 further comprises a processor and a memory (e.g., described with respect to FIG. 5) that may be used to produce the image for the auxiliary display device using the holographic optical element, in addition to any of several other processing tasks typical to mobile devices.
Operatively coupled to the mobile base is a projection device #220 for generating the real image that will be viewed via the holographic optical element (HOE) shown as patent point #230.
The HOE is a thin and transparent surface that is attached to the mobile base via a rotatable hinge 212. In the stowed or inactive position, the HOE simply covers the primary display screen of the notebook. In the deployed or active position, as shown in patent FIG. 2, the HOE transforms the real image for the projection device into a virtual image that is visible to the user when viewed through the HOE. In this mode, the HOE functions as a window through which a projected (and magnified) view of the image displayed by the projection device becomes visible. In other words, the holographic optical element (HOE) reflects a diverging modulated real image projected by the projection device into a virtual image that is directed toward the operator of the mobile device.
Microsoft's patent FIG. 3 is a side view of the example mobile device and display device of FIG. 2 illustrating operation of the various components of the display device.
In several implementations, Microsoft states that the projection device may operate to generate a real image that is only a few millimeters in diameter. In several such implementations, the internal projection surface (also referred to as a "display") may comprise either a liquid crystal on silicon (LCOS) device used in LCOS projectors or digital micromirror devices (DMDs) used in digital light processing (DLP) projectors used in televisions.
Both LCOS and DMD devices use little power to operate and are about the size of an integrated circuit. As such, these devices may be integrated into the front edge of a mobile device below and co-exist with an embedded display screen.
Microsoft used a notebook example because it's likely the target device. The other example provided was that of a smartphone, though the patent figure didn't explain any detail as did the notebook.
Microsoft filed their patent application under serial number 354353 back in Q1 2012 and published by USPTO earlier this month. Considering that this is a patent application, the timing of such a product to market is unknown at this time.
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