Why Black Stripe is bordering a color TV screen?

The black bordering is the envelope of the picture tube. The picture tube has to withstand the high atmospheric air pressure, because the glass envelope is evacuated. In older TVs, a special glass or plastic shields were placed before the picture tube to protect any glass from hitting the viewer in case of an implosion. But modern TVs incorporate implosion protection without any shield. In one arrangement a metal rim band called kimcode is held around the tube by a tension strap. The black bordering is nothing but this metal band for implosion protection, which prevents the glass from spilling over if the implosion happens.

Mechanism of Remote control in TV

In earlier days, remote controls were based on Ultrasonics. The controlling circuitry included a hand held transmitter and a TV-based receiver circuit. Electronic filters and stepper motors were used to allow/select certain frequencies and perform various functions depending on the key pressed. But the recent remote controls use Infra-red rays and a special binary coding mechanism. The code, intensity and wavelength of the IR wave, help to select different functions. Depending on the key pressed, a signal is sent out by IR source, say, an injection laser diode (ILD). IT generates a code in a parallel format. This is converted to a series format by a shift register. This signal is received by photo-sensitive devices such as an avalanche photo diode at the receiver. Here another shift register is used to convert the code back to a parallel form. This operates a one-of-n-decoder, which selects one function from a set of 'n' predefined functions and executes it.