What is an infrared LED and how can you welcome it?
The infracherveniyat LED ce crawled widely in almost all areas on our stomach. This device can be used in home and medical equipment, participation in complex technological processes and military services. In the tazi article, we are talking about semiconductors from infra-red spectrum - we will analyze how the devices are, why they say so and in time we will check the accuracy of the correctness with the improvisation of the means.
Containment: 1. What is infrachervo treatment 2. Device and characteristics on IR LED 3. Kakvo sa 4. Girth per application 5. How do you screw up 6. How to check well for IR diode
What is infrachervo treatment
Let's talk about infra-red LEDs, let's take a look at some infrared (IR) emitters. For some reason, the table on the spectrum on the electromagnetic radiation has been cleared up.
Electromagnetic spectrum table
Soil with ultraviolet radiation, with a paint on the scabies, first turning into visible light - from violet to red, trace to infra-black radiation and ending with the usual radio waves, which are used in radio communications. Zonata, defined kato we see the spectrum, senaricha like that, for some reason we see it. All other ranges, which include infra red, but are invisible.
What is sensible in the infrachervenia range? First of all, toy e is completely harmless for the Horat and animals. And secondly, it is absolutely invisible behind the human eye, but not behind the system for electronic registration - from a photo detector to a video camera.This is why IR LEDs are intended to be widely used both in everyday life and in production.
Important. The ultraviolet spectrum is not obvious, but for the difference from the infra-cherveto, the effect is significant: you can damage your eyesight and get serious burns on the skin.
The Auschwitz infrared range is divided into three subranges:
- Close - 0.74 ... 2.5 microns.
- Medium - 2.5 ... 50 microns.
- Far - 50 ... 2000 microns.
Device and characteristics on IR LED
Theoretically, it’s different how infrared LEDs are distinguished from conventional light emitting diodes. But how did you get it into practice? We will analyze the principle for work and for two mats.
Incoherent LEDs
Structurally, it is a “layer cake”, consisting of two types of semiconductor: n and p. Kogato tokat preminava prez tozi pn transition, negative charge on the electronite (n) se combined with yoni on the positive core of the heart (p). In this moment of energy, all liberating and nie vizhdame is radiated to light.
How does an uncoupled LED work?
But, as we know, LEDs can shine in different colors, that is, they emit light from different wavelengths - from ultraviolet to infrared spectrum. Why? The spectrum on the beam on the crystal is influenced by the type of material from which it is directed. For example, LEDs from aluminum nitride work in the ultraviolet spectrum, gallium phosphide is reddened, and devices from gallium arsenide work in the infrared spectrum.
Leave it alone and let's figure out why they say they're not. All the LEDs are very bright, the frequency is strictly defined, but capturing a small part of the spectrum. The Tazi region is not especially golyama and se namira in a rich color din, but not so.
That is, as a single semiconductor shines, yes, we say, blue, togava tosi does not color purely blue with a defined, strictly defined length on the wall, but simply a spectrum on the radiation on the device, then lie in the blue range. For example, a zinc selenide device has a wavelength between 450 and 500 nm, but it is still visible blue. Tova se vyzhda is clear from the table of sjs spectrum in the valley.
Table for colors and spectrum
It’s also important for LEDs and other bright colors, including infrared ones. For yes, for getting rid of them, the purity is strictly defined, the principle is completely different because of it, and the devices themselves, which work on the same principles, are called semiconductors and lasers.
Laser - Coherent LEDs
The semiconductor laser is still a "layered cake", self-sized on the back of the "cake" and has a strictly defined parameter, which is the same as the length of the length of the length of the defined spectrum or a multiple of it. In this case, the edges on the crystal are polyrate to an opaque coating, and the dolnata and gornata are partly opaque.
Whenever you apply a voltage to the crystal, every case when the LED is conventional: the reason and the spectrum from the wave, lying in a certain range. Radiation, soaked in the morning, the soil and all reflecting from the crystals of the walls. Osventov should lie on the vlnata, to which the crystal is tuned, it is still reflected many times, stop the honor, and all of them fall apart, on top of each other in different phases.
Changes in the course of the crystal, which is a resonator, the duration of the forced recombination is determined; Tazi phase se narich process on laser pumping.Vednaga shom saddened nadvishi zagubata, the soil is laziraneto.
How a semiconductor laser works back kjm sdzharzhanieto ↑
Kakvo sa
How can an LED be infrared and can it be different from an ordinary LED? For example, it is quite difficult, for example, infrared semiconductors and a huge variety of form factors - depending on the technical characteristics and purpose.
In computer bears and remote control, for example, conventional three-millimeter devices, in CD devices and laser subminiature printers in SMD or metal glass cases. Infrared illuminators can have a lot of low power, but also slightly powerful infrared LEDs: conventional, with a diameter of up to 10 mm or in SMD cutia.
Try on for appearing on infra-red LEDs
The flower on the balloon can be very different - from transparent and metallic with transparent seer to matte black. Understanding this, the device’s theses can, yes, they distinguish between the device’s bright light from the worm and the yellow balloons - infra-black LEDs and the tezi are color, but nothing else.
As regards the technical characteristics of the infra-red LEDs, the main ones are as follows:
- Ygl on the spread. Kolkoto on the temple is a parameter, sensible in a little lightening of the fall at the top is determined by the surface of the object, but sharply on the golyama of the area, which is slightly curved with infrared lightening. Measured in degrees per platen ygl - steradiani (Ω).
- Outgoing power. That se is measured in wool (W) or milvati (mW) and can be varied from a dozen milivata to a little cotton wool.
- Working current. For the sake of warranty, please declare the specifications, including MTBF and source power at the source.Measured in ampere (milliampere).
- Prolonged voltage drop. Voltage, some drop at the top of the matrix at rated current. Depend on the crystal material and usually do not overhang 2 volts.
- Set the maximum allowable voltage. Reverse polarity voltage, some of the crystal can be wasted without electrical damage. For infrared devices, usually a little from 1 volt.
- The length has been cut out for a valnata. As the LED is laser, then all the grounds are one length per wall and the product is disassembled. This is an ordinary infrared LED, which is often covered by the radiation from it, which is measured in nanometers or micrometers (nm or microns).
Girth per application
IR LED can be used almost everywhere today.
In Domakinsky Uredi… Remote control units (RCU), laser printers, computer bears, CD players, etc.
Remote control with infrared LED (the glow is invisible, but the camera on the mobile phone is not detectable)
In the system for sighurnost. Organized on an invisible alarm fence, invisibly illuminated on the object for night cameras for video surveillance.
Organization on LED barriers
Vvv military sphere... Invisible from the naked eye of the laser, infra-red sights, systems for pointing at rockets, rangefinders, searchlights for devices for night vision.
Device for night vision with IR illumination
In medicine… Monitor for heart rate, aparati for blood pressure, thermometry, devices for treatment and prevention of leather and skins, scanners, devices for laser surgery and many others.
Infrared blood pressure monitor
Industrially equipped… Sensors for movement and armor, flaw detection, distance measuring, IR field and plumb, devices for transmitting information via optical communication lines, sources for pumping the power of a laser solid body.
Laser IR LED with optical cable, connected to it back kjm sdzharzhanieto ↑
How do you screw up
Connected to an infrared LED is not distinguishable from connected to a conventional one, emitting light. And you need to connect the DC verigata through a limiting resistor, which will determine the rating of the working current for the device. E, do not take away that the infrared LED is a polar device, therefore, it is necessary to apply the "plus" of the anode and the "minus" of the cathode. In this case, it is small, if a resistor is included in the verigata, it is not a value.
Nai-simple circuit for connection to IR LED
For yes, calculate the cost of the current-limiting resistor, tryabva, you know:
- voltage drop to the top of the LED in time for direct injection (available in the passport);
- LED rated working current (available in the passport);
- resistance to voltage protection.
The calculation itself is exceptionally simple. Take out the voltage drop in the semiconductor from protecting the voltage and intend to drop the voltage of the pres resistor:
U = Usup. - Drop the top of the LED
Now, we calculate the cost of the resistor, which is more important to determine the need for a current to exceed the verigata, using the law per ohm:
R=U/I
kadeto:
- R e necessary resistance to the resistor in ohms;
- U e voltage drop on the resistor (see parvata formula) in volta;
- I e nominal current prez LED in amps.
Ako LED is relatively powerful, instead of a resistor, it uses a driver - an electronic current stabilizer.A driver is also needed, but the voltage is not stable.
Important! Driver trip and osiguri accurately or slightly current, for which a particular LED is rated.
Connected to LEDs through a simple driver, sloben to an integrated stabilizer
Dolnata often on the figure showing the answer to the value of the resistor with the required current.
How to check the correctness of the IR diode
Let us teach you how to check if you are healthy on the IR LED. Let's remember some of the most common damage on a daily basis - damage to the IR diode for remote control (RCU). How can you check if the LEDs are working, without letting them splurge on their own remotely? In the edges on the edges of the radiation on the takiva of the device, it is invisible for horata. Yes, it's invisible, but it looks perfect on a video camera.
Take a smartphone, put it in the photo mode, bring it remotely to the camera on a mobile device, the onslaught is arbitrary and the bud is on display. Ako vsichko e along with the remote control, then we see how the LEDs for the ground and the moment.
Checking for IR LED in remote control with the help of a camera on a mobile phone
The result can be obtained from a web camera or any other video camera with a control display.
Ima and a friend method for testing on an infrared LED - with the help of a multiset (tester). It is much more convenient, but the LED is not soldered anywhere. For yes, send tov, imate the need from all sorts of multisets, some ima mode on the testvane on the diode.
Tova device ima mode on testvane on diode
The infrared LED is checked by checking the last beginning. The device is now switching to the power supply mode on the diode (the arrow is indicated in the picture above) and connect the LED conductors to the other side, first one polarity, next to the other. Be aware that voltage drops are measured in tosy mode.
Scheme for connecting to an infrared diode kjm tester
When one from the polarity, it decreases by voltage, then on the crosshair on the emitter it is still much smaller and the camera on the smartphone is still visible as a diode of light.
Battery LED check
Is it possible to check the LEDs without pre-capturing the scarf? Moga. Vzemama multitset and vvarshvame operation, as in the previous case. Thanks to the current-limiting resistor, the design elements of the yama will affect the quality of the test.
Tova e vsichko, some tryabva yes you know for infrared LEDs. We now know how these devices work, how they work and where they are used.