TVs "as thin as wallpaper" that emit sound directly from the screen without the need for speakers will be among the big draws when the doors of the CES tech show open later on Thursday.

Big name brands LG, Samsung and Sony all used events on Wednesday to unveil what they each believe are the next generation of televisions.

They included LG's new Signature OLED W, which is only 2.57mm thick and attaches to walls using magnetic brackets, creating the illusion it is mounted into the wall.

Rival Sony meanwhile introduced the latest generation of its Bravia televisions, some of which contain a new technology called Acoustic Sound, which uses vibrations through the screen to emit sound without the need for any additional speakers.

The show floor of the Las Vegas Convention Centre will open for the first time on Thursday, with more than 170,000 people expected to attend over the four-day event.

Smart household appliances are also expected to draw big crowds after Samsung unveiled a second generation of the Family Hub smart fridge that houses a touchscreen on the door.

The new appliance now responds to voice commands for the first time.

LG also revealed a smart fridge able to understand voice commands as part of a link with Amazon's Echo artificial intelligence software, the same technology that powers the Echo speaker.

Some 600 start-up firms will also have the chance to raise awareness of their products, with sleep and well-being technology among the most popular trends already emerging at the show.

Smart mattresses and anti-snoring devices are among those that will be on show, as is Nightingale, an ambient sound device designed to emit "sound blankets" that cut out background noises such as street traffic or dripping taps that can wake people up.