What is Blu-Ray?

What is Blu-Ray?

Blu-ray, also known as Blu-ray Disc (BD) is the name of a next generation optical disc format jointly developed by the Blu-ray Disc Association (BDA) used to store media and PC content.

BDA is a group of leading consumer electronics and PC companies. It has more than 180 members across world.

Its Board of Directors currently consist of:
Apple, Dell, Hitachi, HP, LG, Matsushita, Mitsubishi, Pioneer, Philips, Samsung, Sharp, Sony, Sun Microsystem(Oracle), TDK, Thomson, Twentieth Century Fox, Walt Disney and Warner Bros

                                                  Logo of Blu-Ray Disc



 High-definition video may be stored on Blu-ray discs with up to 2160p resolution (3840×2160 pixels), at up to 60 frames per second. DVD discs had been limited to a maximum resolution of 480i (NTSC, 720×480 pixels) or 576i (PAL, 720×576 pixels).

Sony unveiled the first Blu-ray disc prototypes in October 2000, and the first prototype player was released in April 2003 in Japan.

Each Blu-ray disc is about 1.2 millimetres thick and 12 cm in diameter.
BLU-RAY has pits that are only 0.15 microns (µm) long. This is more than twice as small as the pits on a DVD.
Blu-ray has track pitch of 0.32 microns than 0.74 microns of DVD.

Discs store digitally encoded video and audio information in pits, spiral grooves that run from the centre of the disc to the edges.
A laser reads the other side of these pits -- the bumps.
Blu-ray uses a blue laser of shorter wavelength (405 nanometres) than a red laser (650 nanometres).

There are three Format of Blu-Ray is available: 

• BD-ROM - Read-only format for software, games and movie distribution.

• BD-R - Recordable format for HDTV recording and PC data storage.

• BD-RE - Rewritable format for HDTV recording and PC data storage.

 

Advantages of Blu-Ray:

• Record high-definition television (HDTV) without any quality loss.

• Instantly skip to any spot on the disc.

• Record one program while watching another on the disc.

• Create playlists.

• Automatically search for an empty space on the disc to avoid recording over a program.

• Blu-ray discs are better armed than current DVDs. They come equipped with a secure encryption system -- a unique ID that protects against video piracy and copyright infringement.

• Blu-ray has a higher data transfer rate -- 36 Mbps.

• Do not have the problems of  birefringence and disc tilt. 

 

What is LI-FI?

What is LI-FI?

Li-FI stands for Light-Fidelity 100x faster than Wireless-Fidelity abbreviated as WI-FI.

 Visible Light Communication (VLC) is another term that is sometimes used for this technology.

This is first introduced by Harald Haas at his TED Global Talk and name this idea as "LI-FI".He is Chairman of Mobile Communications at the University of Edinburgh and co-founder of pureLiFi.

It is wire and UV visible-light communication or infrared and near-ultraviolet instead of radio-frequency spectrum, part of optical wireless communications technology, which carries much more information and has been proposed as a solution to the RF-bandwidth limitations.

Visible light communications (VLC) works by switching the current to the LEDs off and on at a very high rate, too quick to be noticed by the human eye. Although Li-Fi LEDs would have to be kept on to transmit data, they could be dimmed to below human visibility while still emitting enough light to carry data. The light waves cannot penetrate walls which makes a much shorter range, though more secure from hacking, relative to Wi-Fi. Direct line of sight is not necessary for Li-Fi to transmit a signal; light reflected off the walls can achieve 70 Mbit/s.

The first VLC smartphone prototype was presented at the Consumer Electronics Show in Las Vegas from January 7–10 in 2014. The phone uses SunPartner's Wysips CONNECT, a technique that converts light waves into usable energy, making the phone capable of receiving and decoding signals without drawing on its battery.

                       A picture of Office Automation through LI-Fi