Holographic screen
Encyclopedia
A holographic screen is a display technology that uses coated glass media for the projection surface of a video projector
. "Holographic
" refers to the coating that bundles light using formed microlens
es. The lens design and attributes match the holographic area. The lenses may appear similar to the fresnel lens
es used in overhead projector
s. The resulting effect is that of a free-space display
, because the image carrier appears very transparent. Additionally, the beam manipulation by the lenses can be used to make the image appear to be floating in front of or behind the glass, rather than directly on it. However, this display is only two-dimensional and not true three-dimensional. It is unclear if such a technology will be able to provide acceptable three-dimensional images in the future.
The computer sends the image to the projector. The projector generates light beams which form the image on the screen. When the user touches the screen, a tactile membrane film reacts to these movements, generating electrical impulses that are sent back to the computer. The computer interprets the received impulses and modifies the projected image according to the information.
The projector generates the beams of light that will form the image on the screen's film, which is adhered to the crystal support. These crystal lenses can be a maximum of 16 millimetre (0.62992125984252 in) across. The projector is usually located behind the screen and must be placed a certain angle above or below the user's line of sight to avoid the dazzling the user. Therefore, it must be trapezoidal projector, so it can compensate for the deforming of the images at this angle of displacement
.
The films are thin sheets of plastic applied to the crystal that allow both visualization and interactivity. There are two types of films:
Video projector
A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other...
. "Holographic
Holography
Holography is a technique that allows the light scattered from an object to be recorded and later reconstructed so that when an imaging system is placed in the reconstructed beam, an image of the object will be seen even when the object is no longer present...
" refers to the coating that bundles light using formed microlens
Microlens
A microlens is a small lens, generally with a diameter less than a millimetre and often as small as 10 micrometres . The small sizes of the lenses means that a simple design can give good optical quality but sometimes unwanted effects arise due to optical diffraction at the small features...
es. The lens design and attributes match the holographic area. The lenses may appear similar to the fresnel lens
Fresnel lens
A Fresnel lens is a type of lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design...
es used in overhead projector
Overhead projector
An overhead projector is a variant of slide projector that is used to display images to an audience.-Mechanism:An overhead projector typically consists of a large box containing a very bright lamp and a fan to cool it. On top of the box is a large fresnel lens that collimates the light...
s. The resulting effect is that of a free-space display
Free-space display
A free-space display is a device that projects images into a volume of free space . Commonly a set of lasers with rotating mirrors are used . Such displays have limited imaging capability but are 3D. Alternately a powerful projector may be focused on a narrow wall of suspended aerosol...
, because the image carrier appears very transparent. Additionally, the beam manipulation by the lenses can be used to make the image appear to be floating in front of or behind the glass, rather than directly on it. However, this display is only two-dimensional and not true three-dimensional. It is unclear if such a technology will be able to provide acceptable three-dimensional images in the future.
Working principle
The display design can use either front or rear projection, in which one or more video projectors are directed at the glass plate. Each projector's beam widens as it approaches the surface and then is bundled again by the lenses' arrangement on the glass. This forms a virtual point of origin, so that the image source appears to be an imaginary object somewhere close to the glass. In rear projection (the common use case), the light passes through the glass; in front projection it is reflected.Interactive holographic screens
Interactive holographic screens add gesture support to holographic screens. These systems contain three basic components:- A projectorProjectorProjector may refer to:*Image projector, a device that projects an image on a surface** Video projector, a device that projects a video signal from computer, home theater system etc.** Movie projector, a device that projects moving pictures from a filmstrip...
- A computerComputerA computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
- Two films
The computer sends the image to the projector. The projector generates light beams which form the image on the screen. When the user touches the screen, a tactile membrane film reacts to these movements, generating electrical impulses that are sent back to the computer. The computer interprets the received impulses and modifies the projected image according to the information.
The projector generates the beams of light that will form the image on the screen's film, which is adhered to the crystal support. These crystal lenses can be a maximum of 16 millimetre (0.62992125984252 in) across. The projector is usually located behind the screen and must be placed a certain angle above or below the user's line of sight to avoid the dazzling the user. Therefore, it must be trapezoidal projector, so it can compensate for the deforming of the images at this angle of displacement
Displacement (vector)
A displacement is the shortest distance from the initial to the final position of a point P. Thus, it is the length of an imaginary straight path, typically distinct from the path actually travelled by P...
.
The films are thin sheets of plastic applied to the crystal that allow both visualization and interactivity. There are two types of films:
- Screen film: This film can be opaque or transparent. It is possible to work with different degrees of opacity that can vary between 90% and 98%, depending on the application (interior, exterior, natural lighting, artificial lighting, etc.).
- Tactile membrane: This film enables interactivity. Capacitive projected technology catches user gestures and sends impulses to the computer.
Uses
Most initial uses of this technology are advertising-related, such as shop windows. An interactive holographic screen can be mounted on the shop windows so that passersby can interact with it. Non-interactive holographic screens in shop windows can be coupled with artificial vision software to adapt ads based on the viewer's characteristics (age, sex, etc.).See also
- PhantasmagoriaPhantasmagoriaPhantasmagoria can refer to:* Phantasmagoria, a type of show using an optical device to display moving images* Phantasmagoria, a video game* Phantasmagoria: A Puzzle of Flesh, a video game sequel to Phantasmagoria...
- Video projectorVideo projectorA video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright light to project the image, and most modern ones can correct any curves, blurriness, and other...
- Rear-projection televisionRear-projection televisionRear-projection television or RPTV is a type of large-screen television display technology. Up until the mid-2000s, most of the relatively affordable consumer large screen TVs up to used rear-projection technology...
- Large-screen television technologyLarge-screen television technologyLarge-screen television technology developed rapidly in the late 1990s and 2000s. Various thin screen technologies are being developed, but only the liquid crystal display , plasma display and Digital Light Processing were released on the public market...
- Free-space displayFree-space displayA free-space display is a device that projects images into a volume of free space . Commonly a set of lasers with rotating mirrors are used . Such displays have limited imaging capability but are 3D. Alternately a powerful projector may be focused on a narrow wall of suspended aerosol...
- 3D display3D displayA 3D display is any display device capable of conveying a stereoscopic perception of 3-D depth to the viewer. The basic requirement is to present offset images that are displayed separately to the left and right eye. Both of these 2-D offset images are then combined in the brain to give the...