Multi-layered, three-dimensional display

Details Multi-layered, three-dimensional display Multi-layered, three-dimensional display

2000-10-13

2004-04-13

Dudek, James (Department: 2871)

Liquid crystal cells, elements and systems

Particular structure

Having significant detail of cell structure only

C349S088000

Reexamination Certificate

active

06721023

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to electro-optic imaging devices for three-dimensional (3D) display applications. More particularly, the present invention concerns a method and apparatus for volumetric 3D displays utilizing stacked, multi-layered, two-dimensional (2D), flat panel technology, such as non-conventional LCD technology.
BACKGROUND OF THE INVENTION
With the continuously increasing demand for improved electronic imaging displays, and with the increasing bandwidth of computers, several 3D imaging display methods have been suggested, including stereovision, computer graphics, holography, vibrating or rotating screens, and split images, all of which have their advantages and drawbacks.
Stereovision has been increasingly developed in recent years; however, it is not a real 3D imaging method and therefore it has its limitations. Specifically, stereovision only takes into account binocular disparity (static parallax), but the other depth information, such as eye accommodation, convergence and motion parallax, are neglected. Another disadvantage is the need for viewing aids, such as eyeglasses and the like.
Computer graphics using 3D animation are also not real 3D. They give the impression of 3D information by shifting and/or rotating motion, and therefore, they have two basic drawbacks: first, a real, physiological 3D perception is not possible, and second, this method requires active intervention during perception, reducing attention and/or intervention for other actions.
Although conventional holography is a real depth 3D imaging method, it is not electronic, and it is therefore not a real-time display application. There are research and development programs on electronic holography at universities, but commercialization is so far not yet practical, due to the large space bandwidth requirements which at present necessitate the use of super computers.
Vibrating or rotating screen displays belong to another class of more recent, real depth imaging displays wherein a volume 3D image is created by lateral or rotational volume-sweeping of a 2D illuminated screen or disk. The disadvantage of this system obviously lies in the cumbersome opto-mechanical projection system.
Split image display refers to a relatively new method of 3D imaging, wherein an illusion of depth is created by projecting to the viewer's eye, via Fresnel lenses, two pseudoscopic images of two different focal lengths, i.e., a foreground image and a background image. The two different focal contents force the viewer to constantly refocus his eyes, thereby creating an eye accommodation and convergence effect. Static and motion parallax also exist with this method. The method does not utilize any mechanical volume sweeping, however, its drawback obviously lies in the limited detailed depth information available from specific objects. For example, an object in the foreground will have a 2D appearance, even though the overall image creates a 3D illusion.
In two different attempts to achieve real depth, or volumetric, 3D displays without referring to mechanical volume sweeping, the use of multi-layered, stacked 2D sliced images or image contours is proposed.
The first proposal teaches the stacking of two types of 2D panels: namely, gas discharge, or plasma, panels on the one hand, and liquid vapor devices on the other. One disadvantage of plasma displays obviously is associated with the production and handling of devices based on vacuum tube technology. Another disadvantage lies in the limited resolutions achievable with this technology.
The second proposal, as described in U.S. Pat. No. 5,745,197, teaches the use of stacked, planar, light-absorbing elements consisting of conventional LCD panels sandwiched between polarizers and quarter-wave plates. For practical reasons, LCD devices may be divided into three classes: (a) devices including conventional pairs of polarizers, (b) devices including one single polarizer, and (c) polarizer-free devices. The reason for this division lies in the fact that polarizers absorb an important part, over 50%, of the display illumination. Therefore, conventional LCD devices, as taught by said patent, are disadvantageous because of the necessity to introduce additional elements such as polarizers, which significantly reduce the brightness, and as a consequence the number of stacked layers, or depth, in a device. The reduced brightness necessitates increased lamp power, which in turn increases power consumption and heat dissipation.
Another disadvantage of utilizing conventional LCD technology is the limited viewing angle. To reduce this problem, additional optical compensation layers, such as quarter wave plates, may be introduced. Such additional compensation layers, however, further complicate the system and increase its cost.
Also, by limiting the image display operation principle of the LCD to absorption modulation (absorptive grey shades), an essential part of image perception based on light scattering is lost. In addition, the necessity to apply a rear backlight is disadvantageous, from both the aspect of the varying quantity of light arriving from different layers, which again limits the achievable depth of the scene or object to be displayed, and from the aspect of additional geometrical depth requirements of the display.
Other examples of possible flat-panel media that may be used for stacking in multi-layered display assemblies are:
1) inorganic or organic, electroluminescent light-emitting diode (OLED) layers;
2) electrochromic layers; and
3) non-linear, electro-optic layers.
The disadvantages of each of these media are: under (1), their permanent color and light-absorbing characteristics, which limit the number and depth of the layers; under (2), their slow response times, which make them impractical for real-time applications; and under (3), their need for high-intensity illumination, which implies expensive and/or bulky light sources.
SUMMARY OF THE INVENTION
The general object of the present invention is to provide methods of, and devices for, real-depth, volumetric 3D electro-optical image displays wherein the 3D images are achieved by utilizing multi-layered structures of electro-optical flat panel display technology, and wherein each of these layers represents a slice through the object to be displayed.
It is a specific object of the present invention to provide a multi-layered structure by stacking an assembly of layers on top of each other, utilizing at least two plastic substrates folded as many times as necessary to achieve the desired number of layers.
It is a further object of the present invention to utilize suitable 2D flat panel media of very high transmittance, having low absorbance, low reflectance or low scattering, in the areas where no image is displayed, so that the 3D image composed of said media does not become obscured in depth, to obtain good quality 3D images having good optical clarity. Advantageously, suitable 2D flat panel media are chosen from non-conventional, polarizer-free liquid crystal (LC) media, including polymer-dispersed liquid crystals (PDLC) and derivatives thereof, such as nematic curvilinear aligned phases (NCAP) and polymer stabilized cholesteric textures (PSCT) or guest-host (GH) dichroic or pleochroic LCs, and combinations and derivatives of these non-conventional media. Such media allow maximal light utilization because they minimize losses of polarizer and in-depth absorption, so as to allow larger depths and numbers of layers to be realized in 3D display devices.
Still another object of the present invention is to provide suitable illumination systems so as to make the image visible during operation of the 3D devices. Specifically, side-coupled illumination, in combination with scattering PDLC layers, enables homogeneous illumination of the object through its 3D depth, so as to allow larger depths and numbers of layers to be realized in 3D display devices.
A yet further object of the present invention addresses the attachment of suitable optical elements on top of a multi-layered imaging (MLI) st

Affiliated with

Also associated with

Rating

Multi-layered, three-dimensional display does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Multi-layered, three-dimensional display, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-layered, three-dimensional display will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3244616