Display technology and Holographic Display

First I wish to share few views on “How actually we see an object”, by the means of scientific way. You probably know that we experience "light" by seeing it bounce off something before being absorbed into our eyes.

Light is the energy that our eyes detect when we see. When there's no light, we won't be able to see anything even if there is nothing physically wrong with us. Light occurs in waves, where the distance between one peak to another is called wavelength. Light is visible at 400-700 nm wavelength. (1 nm or nanometer is one-billionth of a meter.) Microwaves and infrared rays have longer wavelengths than visible light; while ultraviolet rays, x-rays and gamma rays have shorter wavelengths than visible light.

Light may differ in color, brightness and purity. Color, or hue, is dependent upon the wavelength of light. Low-frequency light, or light with longer wavelengths, is reddish; while high-frequency light, or light with shorter wavelengths, is bluish. The brightness of light, on the other hand, is measured by the wave's amplitude (or height). High-amplitude light waves are brighter than low-amplitude light waves. Lastly, purity or saturation is measured by the amount of white light added. Pure light has lesser added white light than saturated light. The Color Tree is oftentimes used to demonstrate the different properties of light. Hue moves around the tree; saturation goes outward; and brightness moves upward.

Display technology

This topic is going to be very interesting for people who call Gadget Geeks. Although there are plenty of technologies available around I will talk about Common applications that uses as electronic visual displays (televisions or computer monitors).

Display devices

In generally we can say a device with an output device for presentation of information in visual or tactile form. If the input information is supplied as an electrical signal, the display is called an electronic display.

In current generation we can list some of the methods that in use for Display technology,

Eidophor, Electroluminescent display (ELD), Electronic paper E Ink Gyricon,  Vacuum fluorescent display (VFD), Light emitting diode display (LED), Cathode ray tube (CRT) (Monoscope), Liquid crystal display (LCD) (TFT LED Blue Phase IPS),  Plasma display panel (PDP), ALiS Digital Light Processing (DLP), Liquid crystal on silicon (LCoS)

And also we can list some of the methods for next generation methods as follows,

Organic light-emitting diode (OLED) (AMOLED),  Organic light-emitting transistor (OLET), Surface-conduction electron-emitter display (SED), Field emission display (FED), Laser TV Quantum dot Liquid crystal,  MEMS display IMoD, TMOS DMS,  Quantum dot display (QD-LED), Ferro liquid display (FLD), Thick-film dielectric electroluminescent technology (TDEL), Telescopic pixel display (TPD), Laser phosphor display (LPD), Flexible display Musion Eyeliner Fog display

Most popular technologies that has being in the recent past,

Cathode ray tube

Cathode ray tube (CRT) is a vacuum tube with an electron gun (a source of electrons or electron emitter) and a fluorescent screen used to view images. This will accelerate and deflect the electron beam onto the fluorescent screen to create the images. The technology uses an evacuated glass envelope which is large, deep, fairly heavy, and relatively fragile. For safety purpose, the face is typically made of thick lead glass so as to be highly shatter-resistant and to block most X-ray emissions, particularly if the CRT is used in a consumer product. A cathode ray tube is a vacuum tube which consists of one or more electron guns, possibly internal electrostatic deflection plates, and a phosphor target. In television sets and computer monitors, the entire front area of the tube is scanned repetitively and systematically in a fixed pattern called a raster. Controlling the intensity of each of the three electron beams, one for each additive primary color (red, green, and blue) with a video signal as a reference an image is produced. In all modern CRT monitors and televisions, the beams are bent by magnetic deflection, a varying magnetic field generated by coils and driven by electronic circuits around the neck of the tube.

CRTs have largely been overshadowed by more modern display technologies such as LCD, plasma display, and OLED, which as of 2012 offer lower manufacturing and distribution costs.

LED display

An LED display is a flat panel display, which uses light-emitting diodes as a video display. An LED panel is a small display, or a component of a larger display. They are typically used outdoors in store signs and billboards, and in recent years have also become commonly used in destination signs on public transport vehicles or even as part of transparent glass area. LED panels are sometimes used as form of lighting, for the purpose of general illumination, task lighting, or even stage lighting rather than display.

There are two types of LED panels: conventional (using discrete LEDs) and surface-mounted device (SMD) panels.[citation needed] Most outdoor screens and some indoor screens are built around discrete LEDs, also known as individually mounted LEDs. A cluster of red, green, and blue diodes is driven together to form a full-color pixel, usually square in shape. These pixels are spaced evenly apart and are measured from center to center for absolute pixel resolution. The largest LED display in the world is over 500 meters long and is located in Suzhou, China, covering the Yuanrong Times Square.[citation needed] The largest LED television in the world is the Center Hung Video Display at Cowboys Stadium, which is 160 ft × 72 ft (49 m × 22 m), 11,520 square feet (1,070 m2).

Most indoor screens on the market are built using SMD technology - a trend that is now extending to the outdoor market. An SMD pixel consists of red, green, and blue diodes mounted in a single package, which is then mounted on the driver PC board. The individual diodes are smaller than a pinhead and are set very close together. The difference is that the maximum viewing distance is reduced by 25% from the discrete diode screen with the same resolution.

Liquid crystal display

A liquid crystal display (LCD) is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals. Liquid crystals do not emit light directly.

LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images which can be displayed or hidden, such as preset words, digits, and 7-segment displays as in a digital clock. They use the same basic technology, except that arbitrary images are made up of a large number of small pixels, while other displays have larger elements.

LCDs are used in a wide range of applications including computer monitors, televisions, instrument panels, aircraft cockpit displays, and signage. They are common in consumer devices such as video players, gaming devices, clocks, watches, calculators, and telephones, and have replaced cathode ray tube (CRT) displays in most applications. They are available in a wider range of screen sizes than CRT and plasma displays, and since they do not use phosphors, they do not suffer image burn-in. LCDs are, however, susceptible to image persistence.[1]

The LCD screen is more energy efficient and can be disposed of more safely than a CRT. Its low electrical power consumption enables it to be used in battery-powered electronic equipment. It is an electronically modulated optical device made up of any number of segments filled with liquid crystals and arrayed in front of a light source (backlight) or reflector to produce images in color or monochrome. Liquid crystals were first discovered in 1888.[2] By 2008, worldwide sales of televisions with LCD screens exceeded annual sales of CRT units; the CRT became obsolete for most purposes.

Holographic display

Holographic display is a type of display technology that has the ability to provide all four eye mechanisms which are binocular disparity, motion parallax, accommodation and convergence.

Electro-holographic display

Electro-holographic display is a type of holographic display that uses electroholography for recording and reconstructing 3D objects. This display has advantages over other 3D displays; for example, it can reconstruct 3D images with full parallax.

The early prototypes of tele-immersive displays require users to wear special goggles and ­a head device that tracks the viewpoints of users looking at the screen. On the other end, the people that appear as 3-D images are being tracked with an array of seven ordinary video cameras, while two other video cameras capture real light patterns projected in each room to calculate distances. This enables the proper depth to be re-created on the screen. So, if a viewer moves his head to the right, he can see the corresponding images that would be seen if he were actually in the room with the person on the screen.

Images on the screen are split and polarized to create a different image for each eye. The goggles then combine these images so that the brain recognizes only one 3-D image. This process is similar to how those old 3-D movie glasses work. Early experiments, like the one at UNC in May, have experienced some glitches, similar to those of normal video-conferencing. The scenes being projected are only refreshed three times per second, which creates a jerky image. If that rate could be improved to 10 frames per second, it would create a seamless projected image that would be like looking through a window at another person. Scientists are developing new technologies to support this type of communication, including:

Internet2 - This would replace the current Internet infrastructure. This new network will have a higher bandwidth and speeds 1,000 times faster than today's Internet. This high-bandwidth, high-speed network is necessary to transfer the large amounts of data that tele-immersion will produce.

Display technologies - Stereo-immersive displays would have to present a clear view of the scenes being transmitted.

Haptic sensors would allow people to touch projections as if they were real.

Desktop supercomputers would perform the trillions of calculations needed to create a holographic environment. Another possibility to support these environments would be a network of computers that share power.

Tele-immersion will blur the lines between real and computer-generated images. It will be the ultimate tele-commuting technology, almost entirely eliminating the rush-hour drive to work. Instead of commuting, people could attend board meetings by projecting themselves into the company's conference room. And if your job requires you to travel, you could still be home for dinner by tele-immersing yourself into the family kitchen. Because this technology is still in the early stages of development, the possibilities are truly endless.

Thanks to all of you.