Why can photoelectric bulbs replace the vision of the eye?
When you step closer to an airplane station or some hotel’s automatic door or some hotel, the door opens automatically; when you enter, the door closes automatically. Automatic door how to see you, right?
Everyone knows humans and most animals use their eyes to see objects because rays of light or reflected rays of the object emit enter the human eye. Light of a small amount of energy is called a photon (photon). Different photons of energy correspond to light of different wavelengths and look at it to see different colors. When the photon enters the eye with a trillionth of a quantity when it reaches the eye’s retina, it causes excitement of eye cells on the retina, that excitement is transmitted to the cerebrum, forming vision, we immediately see the object.
On one side of the automatic door, there was a light source. Its infrared rays illuminate the other’s photoelectric (cells) bulbs. Since the human eye cannot see infrared rays, usually you are unaware. When you walk in front of the door, your body obscures the infrared rays; the photoelectric bulb immediately senses the light ray variation signal, the corresponding electric circuit stimulating reaction opens the door, like seeing a person. Therefore, they call the photoelectric bulb used in this job the electric eye. The human body itself also emits very weak infrared rays. Some electric eyes can also directly “see” that signal. This can eliminate the installation of the light source unit on the automatic door.
The photoelectric bulb consists of an anode (anode) and a cathode (cathode). The cathode has a light-sensitive material. When light shines on the cathode, the photon’s energy is transferred to the electron in the cathode, causing electron emission. This process is called the photoelectric effect. In 1905, Einstein correctly explained this phenomenon and thus received the Nobel Prize for physics. Electrons emitted from the cathode are attracted to them by the anode, forming an electric current proportional to light intensity. Suppose the photoelectric bulb is improved further, using a series of metal electrode plates to magnify the photoelectric emission signal through the secondary electron emission method. In that case, the photoelectric amplification bulb is formed. It takes at least more than tens of thousands of photons to cause the vision of the human eye, while the photoelectric amplification bulb can be seen one at a time, much more sensitive than the human eye. So, in terms of photon count, nuclear physics studies, etc. Photovoltaic amplifiers all have important applications.
Photovoltaic bulbs can be used for automatic door opening, burglar alarms, traffic light control, etc., and measuring light intensity, luminescence counts, etc.