Modern science is actively developing in various directions, trying to cover all possible potentially useful areas of activity. Among all this, it is necessary to single out optoelectronic devices that are used both in the process of data transmission, and their storage or processing. They are used almost everywhere where a more or less sophisticated technique is used.
What it is?
By optoelectronic devices, which are also known as optocouplers, we mean special semiconductor-type devices capable of sending and receiving radiation. These structural elements are called the photodetector and light emitter. They can have different options for communication with each other. The principle of operation of such products is based on the conversion of electricity into light, as well as the inverse of this reaction. As a result, one device can send a certain signal, and the other receives and decrypts it. Optoelectronic devices are used in:
- communication units of equipment;
- input circuits of measuring devices;
- high voltage and high current circuits;
- powerful thyristors and triacs;
- relay devices and so on.
All such products can be classified into several basic groups, depending on their individual components, design or other factors. About it below.
Emitter
Optoelectronic devices and devices are equipped with signal transmission systems. They are called emitters and, depending on the type, the products are divided as follows:
- Laser and LEDs. Such elements are among the most universal. They are characterized by high efficiency, a very narrow beam spectrum (this parameter is also known as quasi-chromaticity), a fairly wide range of operation, maintaining a clear radiation direction and a very high speed. Devices with such emitters work for a very long time and are extremely reliable, they are small in size and perfectly show themselves in the field of microelectronic models.
- Electroluminescent cells. Such a structural element does not show a very high conversion quality parameter and does not work for too long. At the same time, devices are very difficult to manage. However, they are best suited for photoresistors and can be used to create multi-element, multifunctional structures. Nevertheless, due to its shortcomings, now emitters of this type are rarely used, only when it is really impossible to do without them.
- Neon lamps. The light output of these models is relatively low, and they also do not withstand damage and do not work long. They are large in size. They are used extremely rarely in certain types of devices.
- Glowing Llamas. Such emitters are used only in resistor equipment and nowhere else.
As a result, LED and laser models are optimally suitable for almost all areas of activity and only in some areas where it is impossible to do otherwise, other options are used.
Photo detector
The classification of optoelectronic devices is also carried out according to the type of this part of the design. As the receiving element, different types of products can be used.
- Photo thyristors, transistors and diodes. All of them relate to universal devices capable of working with an open type transition. Most often, silicon is the basis of the design and because of this product they get a fairly wide range of sensitivity.
- Photoresistors. This is the only alternative, the main advantage of which is to change the properties in a very complex way. This helps to implement all kinds of mathematical models. Unfortunately, it is photoresistors that are inertial, which significantly narrows the scope of their application.
Beam reception is one of the most basic elements of any such device. Only after it can be received, further processing begins, and it will be impossible if the communication quality is not high enough. As a result, great attention is paid to the design of the photodetector.
Optical channel
The design features of the products can be shown quite well by the designation system used for photoelectronic and optoelectronic devices. This also applies to the data transmission channel. There are three main options:
- The extended channel. The photodetector in this model is distant to a fairly serious distance from the optical channel, forming a special fiber. It is this design option that is actively used in computer networks for active data transfer.
- Closed channel. This type of construction uses special protection. It perfectly protects the channel from external influences. Models are used for the galvanic isolation system. This is a fairly new and promising technology, now continuously improving and gradually replacing electromagnetic relays.
- Open channel. This design implies an air gap between the photodetector and the emitter. Models are used in diagnostic systems or a variety of sensors.
Spectral range
From the point of view of this indicator, all types of optoelectronic devices can be divided into two types:
- Near range. The wavelength in this case ranges from 0.8-1.2 microns. Most often, such a system is used in devices using an open channel.
- Far range. Here the wavelength is already 0.4-0.75 microns. It is used in most types of other products of this type.
Design
According to this indicator, optoelectronic devices are divided into three groups:
- Special This includes devices equipped with several emitters and photodetectors, sensors for presence, position, smoke, and so on.
- Integral. Such models additionally use special logic circuits, comparators, amplifiers and other devices. Among other things, their exits and entrances are galvanically isolated.
- Elementary. This is the simplest version of products in which the receiver and emitter are present in only one instance. They can be either thyristor or transistor, diode, resistive, and in general, any other.
The devices can use all three groups or each individually. Structural elements play a significant role and directly affect the functionality of the product. At the same time, sophisticated equipment can use the simplest, most elementary varieties, if appropriate. But the reverse is also true.
Optoelectronic devices and their application
In terms of the use of devices, they can all be divided into 4 categories:
- Integrated circuits. They are used in a wide variety of devices. The principle is used between different structural elements using separate parts that are isolated from each other. This prevents the components from interacting in any way, except for what was provided by the developer.
- Insulation. In this case, special optical resistor pairs, their diode, thyristor or transistor varieties and so on are used.
- Conversion. This is one of the most common use cases. In it, the current is transformed into light and applied in this way. A simple example is all kinds of lamps.
- Inverse transformation. This is already the exact opposite, in which it is light that is transformed into a current. Used to create all kinds of receivers.
In fact, it is difficult to imagine almost any device running on electricity and devoid of some kind of optoelectronic components. They may be presented in small numbers, but will still be present.
Summary
All optoelectronic devices, thyristors, diodes, semiconductor devices are structural elements of different types of equipment. They allow a person to receive light, transmit information, process or even store it.