CATHODE RAY TUBE
A cathode ray tube (CRT) is a fundamental component of CRT technology. It is a vacuum tube that employs the interaction of electrons and a phosphor-coated screen to create visual images.
The CRT consists of several key elements. At the back of the tube, there is an electron gun composed of a heated cathode that emits electrons and a control grid that regulates the flow of electrons. The electrons are accelerated towards the front of the tube by a series of anodes and focused into a narrow beam.
The front end of the CRT features a screen coated with phosphors, which are substances that emit light when excited by electrons. These phosphors are arranged in pixel-like patterns, forming the basis for image formation. When the electron beam strikes the phosphor-coated screen, it causes the phosphors to emit light, creating a visual display.
To generate the desired images, the electron beam is deflected horizontally and vertically using magnetic fields. This scanning process sweeps across the screen line by line, rapidly illuminating the phosphors to form a complete image. By varying the intensity of the electron beam, different levels of brightness and colors can be achieved.
One of the notable characteristics of CRT technology is the presence of scan lines, which are the visible horizontal lines that make up the image on the screen. The scan lines are a result of the sequential scanning of the electron beam across the screen, with each line being illuminated one after another. These scan lines give CRT displays their unique visual appearance.