Optics: image projectors – Projected image combined with real object
Reexamination Certificate
2001-06-11
2002-11-19
Adams, Russell (Department: 2851)
Optics: image projectors
Projected image combined with real object
C345S005000, C345S007000, C359S489040, C359S493010, C359S506000, C359S630000, C359S888000, C359S890000, C348S014070, C348S014100, C348S014120
Reexamination Certificate
active
06481851
ABSTRACT:
AREA OF THE ART
The invention concerns the area of presentational displays and, more specifically, an improved display system that alters transparency in synchrony with video content.
DESCRIPTION OF THE PRIOR ART
For years writers and filmmakers of science fiction have envisioned display terminals in the future as being see-through yet still able to fully display a high quality image. The practical aspects of such a display is that it permits the viewer to see beyond the display to the background behind and also, the display itself appears less bulky and less intrusive in the viewer's environment. A transparent display offers the unique feature of being placed in environments, such as retail spaces and tradeshows, and does not obstruct the view of important signage and products. While filmmakers can easily simulate this type of video display using computer generated graphics, the actual invention and construction of this kind of video display has been frustrated by numerous problems as evident in the prior art.
A rear projection holographic projection screen
4
, as seen in Prior Art
FIG. 1
, is marketed by Proscreen Inc. of Central Point, Oregon and is one of several technologies that permits a transparent image. A projector
6
, located on a rear side of the rear projection holographic screen
4
, is angled acutely so that a background
2
is seen. The technology of this type of screen is limited by several obvious problems. First, the holographic material is not manufactured in sufficient size which means several pieces must be positioned together forming a visible joint line
3
. Another drawback is that the projector
6
is visible through the screen
4
exposing a blindingly bright projector lens. Another drawback is that the projector
6
and the screen
4
are separate and removed from one another adding complexity to installations, rather than having one single display device. Still another major drawback to the screen
4
is that it is not truly transparent, but milky appearing with luminous colored auras. Another problem is that the image quality is poor lacking accurate color reproduction and lacking sufficient black color levels for appropriate contrast.
A front projection holographic screen
8
seen in prior art
FIG. 2
has been developed as well and suffers from the same problems described above for the rear projection holographic projection screen
4
. The front projection holographic screen
8
is manufactured by Pronova and sold through a U.S. dealer MCSI of Berkeley, Calif. The screen
8
also suffers from having small visible tiles
5
which further deteriorates the image quality.
Another attempt at a transparent display system uses a liquid crystal display panel (LCD)
10
with a see-through screen
12
as illustrated in prior art FIG.
3
. The LCD panel
10
is commonly used as an attachment that fits onto an overhead projector. The problem with such a device is that it requires a backlight (not shown) to make the image fully visible. When no backlight is used the display appears dull and unimpressive. Another drawback is the grid formation between the pixels blocks a portion of the transparency. Still another drawback is that LCD panels are not readily available in large sizes and are more expensive then other displays, such as cathode ray tube (CRT) displays.
Prior art
FIG. 4
illustrates a beamsplitter
14
that permits the background
2
to be seen while reflecting a video display
16
with an image bearing screen
18
. The use of a beamsplitter
14
and other types of reflective/transparent panels has been well known in the art. The “Peppers ghost illusion” utilizes such an arrangement, but in Shakespearean times actual people were the source of reflections creating a live ghostly image on stage. In recent times the video display
16
is used to display images upon the beamsplitter
14
. U.S. Pat. 5,923,469 to Machtig et al. illustrates a variation of this reflected display arrangement using a projector creating a large presentational display with a housing that is extremely open and minimalist in its design (not shown). The beamsplitter permits images to be seen with the same quality as the original source barring one major exception and drawback. The image bearing screen
18
and the light emanating from it must compete with the ambient light from the background
2
. If the light from the background
2
is very intense it will wash out the reflected image from the image bearing screen
18
. It is for this reason the “Peppers ghost illusion” is usually coordinated with great detail to controlled ambient lighting. Another major drawback is that black levels on video displays are associated with the lack of light being produced by the display. Hence, black and other dark colors do not reflect well upon the beamsplitter
14
. For example, if a white spaceship were imaged against black space (not shown) it would appear in the reflection of the beamsplitter
14
that the white spaceship was not in space because the background
2
would appear in the area of the reflection that black space appeared on the image bearing surface
18
. The neutralizing effects of ambient light from the background
2
and the reflection of the image bearing screen
18
and the lack of contrast as a result of the beamsplitter
14
not effectively reflecting dark colors from the image bearing screen renders the display arrangement of prior art
FIG. 4
impractical for most display uses. For these reasons computer displays, televisions displays, and even large public venue projection displays do not produce high quality images if based upon the arrangement illustrated in prior art FIG.
4
.
OBJECTS AND SUMMARY OF THE INVENTION
It is object of the present invention to provide a reflected display system that has an electronically adjustable contrast layer that is adjustable from a transparent to a darkened state for improving the quality of a reflected image.
It is a further object of the present invention to provide a reflected display system that has an electronically adjustable contrast layer that is adjustable between a transparent to a darkened state for improving the quality of a reflected image.
It is yet another object of the present invention to provide a reflected display system that has an electronically adjustable contrast layer that is adjustable from a transparent to a darkened state for improving the quality of a reflected image and the layer being synchronized with video content.
It is a still further object of the present invention to provide a reflected display system that has an electronically adjustable contrast layer that is adjustable between a transparent to a darkened state for improving the quality of a reflected image and the layer being synchronized to video content.
It is an additional object of the present invention to provide an ambient light detector for automatically adjusting an electronically adjustable contrast layer for improving the quality of a reflected display image.
Finally, it is an object of the present invention to provide numerous improvements to the performance and configurations of optical elements of a reflected display.
The present invention aims to provide a transparent video display system that overcomes the significant drawbacks of the prior art as previously discussed. Chiefly the present invention enables a transparent-reflective display to have alterable states of use so that images are viewed upon a transparent piece of glass that can alter to a darkened piece of glass. An assembly that consists of a beamsplitter and an electronically adjustable contrast layer is constructed as a thin sheet of glass and is positioned to reflect a video display. The electronically adjustable contrast layer consists of a shuttering capable material that can be electronically engaged to be in a transparent state and also an opaque (or darkened) state. Liquid crystal shutters are ideal for this invention except they are expensive and not readily available in larger sizes. The preferred electronically adjustable contrast layer is fabricat
Machtig Jeffrey S.
McNelley Steve H.
Adams Russell
Crosby Heafey Roach & May LLP
Cruz Magda
Videotronic Systems
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