Patent Application
20130314416
This disclosure generally relates to volumetric displays, and more particularly relates to a volumetric display that uses multiple arrays of electrowetting mirrors to direct light rays from a projector into a dispersion block.
Several varieties of three dimensional (3D) volumetric displays have been demonstrated that do not require a person viewing the display to wear glasses or limit head movements. However, many of these displays rely in spinning minors or projecting as many as three hundred sixty distinct images to display a volumetric image. What is needed is a simpler volumetric display.
In accordance with one embodiment, a volumetric display is provided. The volumetric display includes a dispersion block, a projector, and a plurality of arrays of electrowetting minors. The dispersion block is configured to define a plurality of voxels characterized as being visibly apparent when illuminated by impinging light. The projector is configured to project one or more light rays for illuminating one or more of the plurality of voxels. The plurality of arrays of electrowetting mirrors are arranged about the dispersion block. Each electrowetting minor is operable to reflect a light ray from the projector toward a selected voxel.
Further features and advantages will appear more clearly on a reading of the following detailed description of the preferred embodiment, which is given by way of non-limiting example only and with reference to the accompanying drawings.
The present invention will now be described, by way of example with reference to the accompanying drawings, in which:
The display 10 generally includes a dispersion block 12, sometimes known as a volumetric diffuser, in which an image 14 appears when properly directed light rays 16 are projected into the dispersion block 12. In general, the dispersion block 12 defines a plurality of voxels that typically become visibly apparent when illuminated by impinging light. An example of the display 10 described herein was demonstrated using a volumetric diffuser that included a transparent container formed of glass to define the dispersion block 12. The transparent container was filled with a solution or mixture of food grade powdered cornstarch suspended in water. However, other suitable materials are contemplated for making the dispersion block 12, such as Aerogel™ available from BuyAerogel.com. Another suitable dispersion block may be formed by laser etching a pattern of diffusion locations within a volume of glass. Such a volumetric diffuser may be provided by Crystal Moments Pte. Ltd., Website:
The display 10 generally also includes a projector 20 configured to project one or more of the light rays 16 for illuminating one or more of the voxels 18 in the dispersion block 12. As suggested by
The display 10 generally also includes a plurality of arrays 22a, 22b, 22c (hereafter often the arrays 22) of electrowetting minors 24a1, 24a2, 24a3, 24a4, 24a5, 24a6, 24b1-24b6, 24b1-24b6 (hereafter often the mirrors 24) arranged about the dispersion block 12. While
By way of example and not limitation, an electrowetting minor may use Galinstan as the ‘oil’ layer in an electrowetting cell to provide a reflective surface that can be oriented or angled by applying voltages to the electrowetting cell. A suitable array of electrowetting mirrors is described in U.S. patent application Ser. No. 13/071,925 by Kuhlman et al., titled DISPLAY USING A TRANSREFLECTIVE ELECTROWETTING LAYER, filed Mar. 25, 2011, the entire contents of which are hereby incorporated by reference herein. In general, each of the minors 24 is operable to reflect a light ray (16a, 16b, 16c) from the projector 20 toward a selected voxel 26 at a selected location in the dispersion block 12. Accordingly, the projector 20 and arrays 22 of minors 24 cooperate to intersect a plurality of light rays 16a, 16b, 16c at the selected voxel 26 so that the selected voxel 26 is more apparent than voxels illuminated by one of the light rays 16 as it passes through the dispersion block 12 toward the selected voxel 26.
The display 10 may also include an optical device 28 interposed between the projector 20 and the arrays 22. As the projector 20 may have a limited angular range of directions that the light rays 16 can be projected. As such, the optical device 28 is provided to direct the light rays 16 from the projector 20 to arrays 22. By way of example and not limitation, the optical device may include an electrowetting lens as shown in U.S. Pat. No. 7,352,512 to Hendriks et al., titled VARIABLE FOCUS LENS, issued Apr. 1, 2008. Alternatively, the optical device 28 may include a movable mirror, or a switchable minor generally described as being operable to two states: transparent or reflective. For example, an LCD filled with crystals that are reflective in one state is available from Kentoptronics, or an electrowetting cell filled with liquid gallium, or an electrochromic minor. A more detailed description of how to time-multiplex and direct images for displays can be found in U.S. patent application Ser. No. 12/853,647 by Kuhlman et al., titled DUAL VIEW DISPLAY SYSTEM, filed Aug. 9, 2010, the entire contents of which are hereby incorporated by reference herein.
The display 10 may also include an anti-reflective coating 30 upon the dispersion block at least where light rays reflected by the arrays enter the dispersion block. The anti-reflective coating 30 may help to prevent or reduce a portion of the light rays 16 from reflecting off the dispersion block 12, thereby reducing the amount of light energy impinging on the selected voxel 26, and potentially reflecting toward a person viewing the display 10. A suitable anti-reflective film is Vikuiti ARMP-200 available from 3M corporation.
While
The light rays 16 projected by the projector may be determined based on a three-dimensional model of an object that is to be seen as the image 14 in the dispersion block 12. Then determining how many of light rays 16 are to intersect at the selected voxel may be based on how brightly the selected voxel 26 is to be illuminated. Selecting which of the minors 24 light rays are to impinge on, and determining the angle or orientation of the particular mirror so that the light ray impinges on the selected voxel 26 is a simple matter of geometry.
Accordingly, a volumetric display 10 using electrowetting minor arrays 22 is provided. By using the arrays 22 to direct the light rays 16 toward a selected voxel 26, a volumetric display 10 is provided that uses a fixed diffusion media (the dispersion block 12), and is able to independently adjust the angle of reflection by each of the minors 24 forming each array (22a, 22b, 22c) for each individual light ray (16a, 16b, 16c). As such, the arrays 22 provide greater flexibility of reflection angles than is otherwise possible with fixed minors, and so is able provide for greater alignment of the light rays 16 into the dispersion block 12 to account for dimensional variations due to manufacturing tolerances and in-use vibration.
While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow.
