A Blu-ray is a shiny disc. 

A Blu-ray is a shiny disc. 
It uses a blue light to work. This light is very special. It helps the disc hold more information. This makes movies look very clear. 
Because it holds so much, it can play high-quality video. It can even play very clear 4K video. Some discs hold even more than others.
These discs are the same size as a DVD. They are made of plastic. A tough coating helps stop scratches. 
Many people use these discs to watch films at home. It is a great way to see movies.
A Blu-ray is a digital disc used to store data. 

Blu-ray gets its name from the blue laser it uses. A DVD uses a red laser to read data. The blue laser has a shorter wavelength. This means it can pack information much closer together. Because of this, a Blu-ray disc can hold much more data than a DVD. This extra space allows for high-definition video. This makes the picture look very clear on a screen.
Standard discs can hold 25GB of data. Many movie discs use two layers to hold 50GB. 
A Blu-ray is a special digital disc used to store lots of information. 

This technology works using a tiny beam of light called a laser. While a DVD uses a red laser, a Blu-ray uses a blue laser. This blue laser has a shorter wavelength, which is a way to measure the light.
People have been working on this for a long time. Sony showed the first prototypes in October 2000. A man named Kees Schouhamer Immink even won an Emmy award for his work on DVDs and Blu-ray. The first player was released in Japan in April 2003. However, the format was not released to the whole world until June 20, 2006. 
There are many different sizes for how much data a disc can hold. A standard single-layer disc holds 25GB of data. Most movies use a dual-layer disc, which holds 50GB. 

You might notice that Blu-ray discs feel very sturdy. This is because makers added a tough coating called Durabis.
A Blu-ray Disc, often called a BD, is a high-capacity digital optical disc storage format. It was designed to replace the older DVD format by providing much higher data density. This allows the disc to store high-definition video, such as 720p and 1080p resolutions. Today, Blu-ray is a primary medium for feature films and video games. It is used by major gaming consoles, including the PlayStation 3, PlayStation 4, PlayStation 5, Xbox One, and Xbox Series X. 
The technology relies on a blue laser to read data from the disc. This is the namesake of the format. While DVDs use a red laser with a longer wavelength, Blu-ray uses a blue laser operating at 405 nanometers. This shorter wavelength allows the laser to focus on much smaller spots. Because the laser can focus so tightly, information can be stored at a much higher density.
Blu-ray discs come in several different capacities depending on their layers. A standard single-layer disc holds 25GB of data. The industry standard for feature-length movies is the dual-layer disc, which holds 50GB. For users with BDXL re-writer drives, even larger capacities are available. These include triple-layer discs holding 100GB and quadruple-layer discs holding 128GB. 

The development of Blu-ray was a long process involving many companies. Sony unveiled the first prototypes in October 2000. The first prototype player was released in Japan in April 2003. However, these early players lacked a standard for pre-recorded movies. Hollywood studios required digital rights management, or DRM, to prevent unauthorized copying. This led to the creation of the Advanced Access Content System, known as AACS. The Blu-ray Disc Association (BDA) was formed to manage the format's development. 
When Blu-ray was released worldwide on June 20, 2006, it entered a period known as the high-definition optical disc war. It competed directly against the HD DVD format. HD DVD had a head start in the market, and early Blu-ray sales were slow. However, the format gained massive support through the Sony PlayStation 3 console. Major film studios also began choosing Blu-ray over HD DVD. By January 2007, Blu-ray discs were outselling HD DVDs. In 2008, Warner Bros. announced it would release movies only on Blu-ray. This caused a chain reaction where retailers like Walmart and Best Buy dropped HD DVD. Toshiba eventually discontinued HD DVD in February 2008, leaving Blu-ray as the industry standard.
Video quality on Blu-ray has continued to evolve through various specifications. The initial specification supported a maximum resolution of 1080p. It allowed for up to 24 progressive or 29.97 interlaced frames per second. Newer revisions allowed players to support even higher resolutions. Ultra HD Blu-ray players can now play 4K resolution at up to 60 frames per second. 
To ensure the discs remain functional, manufacturers developed special coatings. Because the blue laser requires a very thin layer for high density, the discs are sensitive to damage. In 2005, TDK announced a thin, ultra-hard polymer coating called Durabis. This coating protects the bare discs from scratches and damage. This advancement meant that bulky protective cartridges were no longer necessary for consumers.
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