In Orwell's 1984, what is the purpose of the telescreen?
In 1984, the telescreen is a tool used by the Party to detect instances of rebellion. You will notice in Part One, Chapter One, for instance, how Winston keeps his back to the telescreen when writing in his diary. This is to prevent the Party from seeing his diary because he knows that if they found it, he would face some harsh and violent punishment, like a forced labour camp.
That the telescreen cannot be turned off (except by Inner Party members) gives us another glimpse into its purpose. The telescreen is designed to monitor every movement and capture every conversation between Party members, whether they are at home, at work or in some other public place. As such, the telescreen also functions as a deterrent against breaking the rules. People are far less likely to commit a crime, for instance, if they know that Big Brother is indeed watching them and that they have little chance of getting away with it.
The telescreen is a propaganda tool used by the state ("Big Brother") to get into people's heads and control them. It also monitors everyone's actions and speech, completely controlling every aspect of human existence. These telescreens are everywhere - there is no escaping them in this horrible society Orwell has shown us.
The telescreen is used to constantly survey the people and put them under pressure of the government. they use them to make sure everyone is following big brother.
The people are under constant surveillance, which is a characteristic of a dystopia. They have no freedom of movement and their emotions, words, actions are also observed to discern whether they are loyal supporters of the Party.
The purpose of the telescreen is to maintain control over the Oceanic society. The party uses it as a tool to differentiate between the supporters of Big Brother, a manifestation of the Party, and dissidents, those that want to oppose or rebel against an authoritative party. It functions as a form of surveillance; people are unable to escape the scrutiny and are never sure when they are being observed or listened to. This ensures that they are wary of not only their words and actions but also their thoughts as they are given away by their facial expressions.