Introduction
Optical sensors are instruments that emit a visible or infrared beam from the light emission element in them.
A reflective-type photovoltaic sensor remains usually used to detect the reflected light beam from the target.
A Thubeam sensor remains used to measure the change in the amount of light, which occurs because the target crosses the optical axis, emitting a beam of light from the light-emitting element, then received by the light reception element and by the light sensor three models, as follows:
Reflective model
This model contains light-emitting elements and light receivers in one room, where the sensor receives light that reflects from the target.
Model (Thrubeam)
this form contains a transmitter and receiver separated from each other.
And when the target remains located between the transmitter and the receiver, the light is cut off. Reflective model this model includes both light-emitting elements and light receivers in one chamber. When light remains emitted from the inverter element, it reflects and returns to the light reception element, and when the target is present, the morning is interrupted.
Light sensors are, therefore, photovoltaic devices that convert photon-shaped photons, whether visible or infrared, into electron-shaped electrical signals and remain classified into several types in what comes: light-emitting light cells are light devices that release free electrons from a light-sensitive material when they collide with a photon with sufficient energy, as the amount of energy photon has depends on the frequency of light, as the frequency increases, the greater the photon energy that converts light energy into electricity.
Photoconductive cells:
They work by changing their resistance when exposed to light, and photovoltaic occurs through light collisions with a semiconducting material that controls current flow when passing through them, which means that more light produces more current at a particular effort, and the most common conductive material is cadmium sulfide used in LDR light cells.
Photovoltaic cells generate power commensurate with the receiving radioactive light energy, dropping light energy on two semiconductors, resulting in a 0.5-volt voltage, and selenium remains often used, especially in solar cells.
The photovoltaic sensor is a type of key, relying on the principle of its work on the presence of switches. That works and depends on whether or not to receive light. These sensors reveal the presence or absence of an object without direct contact and do not contain corrosive mechanical parts. These keys can remain installed at a considerable distance, and these sensors remain indicated to remain involved in large applications in the industry.
fiber optic sensors
the types of optical sensors include the point sensor, the distributed sensor, the external sensor, the internal sensor, the beam sensor, the reflective diffuser sensor, and the retroflex sensor, and depends on the principle of its work on two components: the transmitter, the optical source, the receiver, i.e., the optical detector, and two types of these devices depend on where to change the light beam for the sensor.
The external optical sensor remains known to do so if the light beam leaves the fiber optic cable before it continues on its path, but if it continues in the fiber cable optical and not inside the same line it remains known as the internal optical sensor. there mean three types of optical sensors based on optical sensor and transceiver mode; these types are as follows:
one-way light sensor:
place the transmitter and receiver in the light sensor, where they point to each other, and create a straight path to the light beam, and when the body passes between this path, the intensity of light changes, which means the discovery of the object. Reflective sensor: the transmitter and the receiver are parallel, and when the body passes, it reflects on the transmitted light. The receiver measures that reflection.
Retroflex sensor: the transmitter and receiver are placed in one chamber, sending the transmitter a light beam that reflects through the reflector and remains received by the receiver, and if an object enters between the path of the light beam, it breaks down, depending on the difference in the intensity of light and some other factors the thing can remain detected. one of the most important applications of optical sensors remains: satellites. Imaging. Medical tools. Quality and process control applications.
recoil sensors
UV these sensors measure the strength or intensity of UV radiation. A shorter wavelength than visible rays characterizes this type, although longer than x-rays, and remains indicated to receive a kind of energy signal. The signals outside mean electrical signals directed directly at an electrical meter.
These signals can remain converted into a digital-analog converter and then into a computer to collect data. create reports and graphs, and remain used in several areas such as pharmaceuticals. Automobiles, and robots, which remain also used in the chemical industry.
Some of the most prominent types include UV light tubes:
used to monitor UV air treatments, water treatment with the same radiation, and solar radiation.
light sensors:
used to measure the intensity of fallen light. UV spectrum sensors: devices used in scientific imaging, measuring the radiation spectrum that burns human skin.
reflective sensors – infrared
It is an electronic device that measures and detects infrared radiation, and these devices have two types: active and passive. Active sensors work by emitting rays from active sensors and notice them because they contain two parts:
the light-emitting diode and the receiver.
When a Physical object approaches the sensor, the infrared light is reflected from the light-emitting diode and detected by the receiver. It remains used heavily in barrier detection systems such as robots, and negative sensors detect and do not emit radiation.
Radiation from the light-emitting diode.
one of its most important applications is work that requires motion detection. such as in-house security systems. When a moving object enters, generating infrared rays in the detector sensor range. The device measures the difference in radiology levels between the two thermal, electrical elements. Then the sensor sends an electronic signal to the private computer, which issues a warning.
laser sensors
This type remains highly illuminated, allowing measurement or positioning to remain given precisely. And is fast-measuring, including distance sensors, laser projectors, laser light curtains, and PV laser sensors.
Review Optical Sensors – Introduction, Reflective model and More.