A 3D TV, or three-dimensional television, is a television that can display images in three dimensions, creating a sense of depth and realism. To qualify as a 3D TV, the device must have the following features:

1. 3D Display Technology: The TV must use a display technology capable of showing images in 3D. This can be achieved through various methods, such as active shutter glasses, polarized glasses, or lenticular screens.

2. 3D Content: The TV must be capable of displaying 3D content. This means it should have the necessary hardware and software to process and display 3D signals.

3. 3D Glasses: To experience the 3D effect, viewers must wear special 3D glasses. These glasses synchronize with the TV to alternate the images seen by each eye, creating the illusion of depth.

According to a report by Statista, the global 3D TV market was valued at approximately $4.6 billion in 2020 and is expected to grow at a CAGR of 5.5% from 2021 to 2027. This growth is driven by the increasing demand for high-quality entertainment experiences and the advancement of 3D display technologies. The report also highlights the importance of 3D content availability, as it is a crucial factor in determining the success of a 3D TV.

The active shutter glasses method is one of the most common 3D display technologies used in modern 3D TVs. These glasses use liquid crystal shutters to alternate the images seen by each eye at a high refresh rate, typically 120Hz. This method provides a clear and immersive 3D experience, but it requires synchronization with the TV and can be uncomfortable for some viewers due to the weight and heat generated by the glasses.

Polarized glasses are another popular method for 3D TVs. These glasses use polarized filters to separate the images for each eye. The TV must have two separate image streams, one for each eye, which are then polarized differently. This method is less expensive and more comfortable than active shutter glasses but may not provide as sharp or immersive an experience.

Lenticular screens are a newer technology that uses a lenticular lens to create the 3D effect. This method does not require special glasses and can be viewed from multiple angles. However, it is less common in consumer TVs due to its higher cost and limited 3D content availability.

In conclusion, a 3D TV must have 3D display technology, be capable of displaying 3D content, and require the use of 3D glasses to qualify as a true 3D TV. The choice of 3D display technology depends on the viewer's preferences and the available content.