In this section, you will learn briefly about the difference in diodes (somewhere I heard something, in some cases I noticed it myself, the information is not confirmed)
Clicking on the diode model will open DATASHEET (technical documentation) of the diode from the manufacturer's website.
Briefly about the temperature of light: temperature is measured in kelvins,
2600-3700K - Warm white (Warm White) the lower the value, the more pronounced the yellow.
3700-5000K - Neutral White (Neutral White) white with a hint of yellow.
5000-8300K - Cool white (Cool White) the higher the value, the whiter the light will be with a predominant blue tint.
LED - A very economical diode, but far from being the brightest. brightness reaches only 200Lumen
Next come different diodes in order of novelty, they all have a wide color temperature palette, different brightness and power options from 2.8V to 36V, while the higher the voltage, the lower the ampere consumption. More information can be found on the CREE website.
One of the first CREE LEDs that was used in large quantities in a flashlight. brightness reaches 251Lumen
It shines much brighter than LED, but also consumes more. brightness reaches 307Lumen
XP-G - brightness 493Lumen
Brightness 586Lumen
Perhaps the most common diode, has an incredible number of shades and varieties such as XM-L T2, T3, T4, T5, T6, U2 + each of the types has a very wide range of color temperatures from yellow to white blue. brightness reaches 1040Lumen
Exactly the same as the previous diode, but brighter and slightly more economical + the color palette is even wider, includes a new XML2-U3 bin, the brightness reaches 1052Lumen
More compact + it's brighter. brightness reaches 1150Lumen
Brightness reaches 1175Lumen
Brightness reaches 1950Lumen
MT-G2 - brightness reaches 1987Lumen
Brightness reaches 1833Lumen
XHP35 Hi - brightness reaches 1483Lumen
Brightness reaches 2546Lumen
Brightness reaches 2654Lumen
Brightness reaches 4022Lumen
Brightness reaches 4292Lumen
A small clipping from an article found on the Internet.
CREE XM-L - this LED has become a real breakthrough in the world of flashlights:
Large range of luminous flux from 250 to 1100lm;
- excellent efficiency even when operating at a quarter of the rated power;
- low price;
The CREE XM-L LED has displaced most of the previously used LEDs from the flashlight market (eg SSC P7, CREE MC-E, Luminus SST-50). After the appearance of flashlights on 3 or more XM-L diodes, the Luminus SST-90 diode passed its positions, the flashlights on which were considered the brightest among mass-produced ones. Moreover, the brightness of LED lights on several XM-L diodes was compared with the brightness of xenon lamps.
The use of XM-L in lens lamps (lamps with beam focusing) was dictated by one big drawback of zooms on the XR-E diode - low brightness with a wide beam (maximum defocusing). The brightness of classic XR-E lenses is catastrophically insufficient for normal illumination of a large uniform circle of illumination. But the whole idea of a lens lamp is its versatility - the ability to shine well both far and near. The problem was solved mainly by reducing the maximum beam opening angle of such lamps (that is, such a lamp did not shine widely anyway).
With the advent of XM-L diodes, this problem was solved. Since these diodes are much brighter, they provide sufficient brightness with a wide beam. However, it is erroneous to assume that a lens lamp on an XM-L diode will have a greater beam range. The structural features of the XM-L LED do not allow the beam to be focused well enough by conventional methods. Most of the light beam during focusing is lost on the inner walls of the lamp. Due to this feature, the lens lights on the XM-L do not exceed but are not inferior in beam range to the classic zooms on the XR-E diodes.
The problem of choosing an LED is acute due to their wide range and unlimited price range. The production technology and parameters of LED lamps are accelerating very quickly. It is difficult to keep up with new products, it is even more difficult to figure out which diode is better, which is newer and what should be bought in this or that case.
Of course, you should choose a light source based on your needs. If you are a fanatic of novelties and like to measure the length and width of the beam in the company of like-minded people, naturally, you need the latest super-bright novelties. For hunters, fishermen, divers and other lovers of active pastime, the brightness, focusing or scattering of the beam, its color shade are important.
Deciphering the bin codes of LEDs
In the production of LEDs, they are assigned bin codes. At first glance, this abracadabra does not mean anything. Only knowing the classification, it becomes completely clear which diode is in front of you. The LED bin includes data on the housing design, color subgroup, color shade, brightness code. There are additional digits related to the internal production code, for the user they have no value.
For example:
XPGWHT-L1-1C0-R5 is a diode with XPG package, color - WHT (white), subgroup L1 - white, 1C0 - shade according to ANSI table, R5 - brightness code (139-148 lumens at 350 mA).
Cree XLAMP XR-E
A common, but rather outdated LED. It is a small crystal with a protective glass lens mounted on a substrate that acts as a heat sink and serves as the basis for contacts.
The light output depends on the brightness code and ranges from Q2 (87.4 to 93.9 lumens) to R2 (114 to 122 lumens) at 350 mA. As a rule, a diode of this class is used in inexpensive flashlights. The maximum temperature of the light-emitting crystal is up to 150 °C, when operating with a maximum current of not more than 1 A and a voltage of not more than 3.9 V.
Available in colors:
warm white - 2700-3600°K;
neutral white - 3700-5000°K;
cold white -5000-10000°K.
Cree XLAMP XP
- XPE. This series is particularly popular due to the combination of robust design, high light output and reasonable cost. Externally, the crystal is larger than the previous series, the reflector is shallow. Maximum temperature 150 °C, current 1 A, voltage 3.4 V. Cree XPE has a wider temperature scale of colors, the “Outdoor white” shade has been introduced into the scale with a range of 4000-5300°K. This is a more natural cold white color. Luminance bins: N4, P2, P3, P4, Q2, Q3, Q4, Q5, R2, R3, these are 144-280 lm. Luminous efficiency 19-34 lm/W.
- XPC. This series is a modification of XP-E with a current of 0.5 A and a voltage of 3.5 V. Color shades and luminous flux power are in the same range as that of the prototype. The light output is higher (35-59 lm / W), respectively, we can talk about a clear advantage in this parameter. XPE and XPC are used in small handheld flashlights.
- XPG. New generation LED with superbrightness and efficiency. It has a relatively large crystal area, can withstand up to 1.5 A. Light output leaves far behind its predecessors and is in the range from 90 to 139 lm / W. Maximum luminous flux 346-534 Lm. The color shade is divided into 4 groups. Luminance bin classification: Q4, Q5, R2, R3, R4, R5, S2, S3 - determined at a current of 700 mA. Diodes of this class are used for powerful handheld, sporting flashlights. For long-range, super-bright flashlights, the latest XP-G2 system should be used, which has more light output at standard characteristics.
Cree XM-L
Very powerful LED (10 W) used in professional flashlights and stationary lighting sources. The crystal is 2.5 times larger than XPG, which provides a wide beam of light. If you use a shallow reflector, you get a large jellied spot from the lantern. The luminous flux at a current of 3 A can reach 900 lm. The maximum luminous flux depending on the brightness bin is 1008 lm. The classification of brightness bins is determined at a current of 700 mA, the following are used: S6, T2-T6, U2, U3 (similar to Cree J-A5).
Which diode to choose?
If light characteristics are important to you, then you don’t have to look at the brand of the LED, since it determines only design features. There is no need to buy a powerful Cree XM-L diode for a key fob flashlight, XPE is enough here. For powerful and reliable light sources, XP-G, XP-G2, XM-L, XM-L2 are better suited.
The color group is a matter of taste. The best options are neutral or natural white. The exception is professionals who use LEDs in their optics and the spectral shade is important to them.
The power of the flashlight depends on the power source, but the brightness directly on the bins. At a current of 350 mA, Q5 and R2 will be the brightest, at a current of 700 mA - T6, S3 or U2, U3. When choosing brightness bins, keep in mind that some of them, for example, U, can only work in the cold spectrum, so for flashlights with soft, warm light, it is better to choose something of their T encoding.
Error
- Body diameter - 28 mm.
- Head diameter - 32.5 mm.
- The depth of the battery compartment is 71 mm.
- The diameter of the battery compartment (internal) is 23 mm.
- ML - power from 0.25 to 1.6 W. Designed mainly for emergency lighting of small rooms;
- MX - power from 2 to 4 watts. Used for lighting residential premises;
- XB - power 3-5 watts. The scope of application is quite wide - from portable lights to lighting large warehouses;
- XH - ceramic LED power from 0.6 to 1 W. Due to the high luminous flux / power ratio (150-180 lm / W) they can be used to illuminate houses, offices, etc.;
- XHP35 - powerful (13 W) LEDs. Designed for directional radiation, for example, with light signaling on roads and lighting parking lots;
- XM - power 10 watts. Used in portable flashlights and headlights;
- XP is the most extensive line. Power from 2 to 10 watts. Both white and colored are produced. Due to the variety of models, they can be used in almost any application;
- XQ - miniature LEDs with a power of 1 to 3 watts. Available in both white and color versions. Used for night illumination of architectural structures, as well as greenhouses and large vehicles;
- XR - white and colored diodes with power from 2 to 4 watts. Designed to illuminate night buildings, transport, concert venues;
- XT-E - 5W led. Available in white and blue. The scope of application is quite wide - from household flashlights to lighting warehouses and residential premises.
- P2 Oval 4-mm - colored, presented in red, blue and green. Designed for use in various RGB devices, for example, for backlighting monitors and billboards;
- P2 Oval 5-mm - colored LEDs designed specifically for use in LED-modules such as "creeping line" and various information signs on roads, airports, etc. Presented in red, green, blue and yellow (amber) colors;
- P2 Round 5-mm - both colored and white are presented here, designed to work in conditions of high humidity and temperature changes, therefore they can be used outdoors. Colored LEDs are available in red, blue, green and yellow. White LEDs are divided into two types: cool white and warm white, that is, cold and warm shades;
- SMD - colored and white LEDs in a surface mount package. They are marked with the type CLx. Color LEDs can be divided into single-color, that is, having one pair of anode-cathode and glowing in one color, and full-color, which have three pairs of anode-cathode and are, in fact, three multi-colored (RGB) LEDs in one package . White LEDs, similar to P2 Round output LEDs, come in cool white and warm white varieties;
- P4 - white and colored LEDs designed to create directional radiation, so they can be used to illuminate store signs, traffic signal lights, etc.
- Luminous flux/power ratio (Lm/W) is lower.
- The crystal gets hotter.
- The crystal degrades faster due to increased heat.
- in railway transport;
- automotive industry;
- in street lighting in big cities, etc.
- high-power LEDs, collectively called XLamp;
- super-bright products (High-Brightness)
- MX - LEDs, the power of which is from 2 to 4 watts. Such devices are used for lighting residential buildings.
- ML - power 0.25-1.6 W. They mainly serve as emergency lighting in small rooms.
- XH - are ceramic LED light emitting diodes with a power of 0.6-1 W. They have a high luminous flux / power ratio (150-180 Lumen / W), so they can be used for lighting offices, houses, etc.
- XB - have a power of 3 to 5 watts. They have a fairly wide scope - from portable lights to lighting large warehouses.
- XHP35 are fairly powerful LEDs (13W). Such devices are intended for directional radiation, for example, when illuminating parking lots and light signaling on roads;
- XM - endowed with a power of 10 watts. Found application in headlights and portable flashlights.
- XP - this subgroup represents the most extensive line, the power of which is from 2 to 10 watts. Not only white, but also colored ones are produced. Due to the variety of models, they can be used in almost any application.
- XR - are white and colored diodes, the power of which is from 2 to 4 watts. They are used to illuminate night buildings, concert venues, transport.
- XQ - are miniature LED devices, the power of which is from 1 to 3 watts. Made in white and color. Scope - night illumination of various architectural structures, as well as large vehicles and greenhouses.
- XT-E - led LEDs with a power of 5 watts. Color - white and blue. They have a fairly wide scope - starting with household flashlights and ending with the illumination of residential premises and warehouses.
- P2 Oval 4-mm - colored products, presented in blue, red and green versions. They are used in various RGB devices, for example, to illuminate billboards and monitors.
- P2 Round 5-mm - color and white Cree LEDs that can operate in temperature extremes and in high humidity conditions, therefore they are often used outdoors. White LEDs are divided into two types: warm white and cool white (i.e. warm and cold shades). Colored LEDs are available in red, yellow, blue, green.
- P2 Oval 5-mm - colored LEDs, specially designed for use in LED modules, for example, "creeping line", and various information signs at airports, on roads, etc. They can be red, yellow (amber), green and blue.
- SMD - white and colored LEDs. Color LED products are divided into single-color (with one pair of anode-cathode, glow in one color) and full-color (with three pairs of anode-cathode). In fact, they are three multi-colored LEDs (RGB) in one package. White LEDs come in cool white and warm white varieties.
- P4 - white and colored products, designed to receive directional radiation. It is used for illumination of signal lamps of transport, signboards of shops, etc.
Critical error: The image processing libraries Graphics Draw (gd) or ImageMagick (imagick) must be included in the PHP configuration to generate thumbnails.
Tank007 is a fairly well-known manufacturer of flashlights based on light guide technology. In this review, there will be two models: both are placed in the TK373 case, however, one uses the XM-L T6 as a luminous element, and the second uses the XR-E Q.
In this article, you will learn about the differences between these two models, their advantages and disadvantages, and you will also have an idea about battery life.
Series Features
Flashlights Tank007 TK373 compare favorably with the presence of a zoom: you can change the distance of the optical system and, accordingly, the shape of the light beam by rotating the head of the model.
In this way, you can get both a narrow beam, used to illuminate distant objects, and a wide field of illumination, most often used by tourists, to highlight everything that is nearby. By rotating the head of the flashlight, you can achieve intermediate values, setting the optimal beam shape for each situation.
Case size:
The models under consideration have different lengths: a flashlight with an XR-E Q5 diode is 120 mm, and with an XM-L T6 luminous element it is 130 mm.
The second model is one centimeter longer due to the deeper reflector needed due to the significantly larger element area of the XM-L T6.
Both models are stable when installed on the end, which allows the lanterns to be used as a candle on the table.
Batteries
Four lamps were taken for review: two models with each type of LED. In one pair (XR-E and XM-L), three Maxus brand AAA Alkaline batteries with a total voltage of 4.8 V were installed as power in the cartridges. As an alternative, Panasonic brand lithium-ion batteries were inserted into the second pair, charged up to 4.18 V.
Testing
A comparative analysis of the four lights showed that at the time of launch, the XM-L T6 glow on a lithium-ion battery was the brightest. The second brightest was a model with the same LED, but on batteries, the third and fourth - XR-E Q5 with batteries and XR-E Q5 with batteries, respectively.
However, after twenty minutes the brightness level of the second model (XM-L T6 battery-powered) began to decrease and caught up with the third flashlight, and after another ten minutes it fell to the level of the fourth position.
As a result of tests at the 76th minute, the XM-L T6 flashlight on three AAA batteries reduced its brightness to a minimum, after flashing several times beforehand. At the same time, the brightness level of the XM-L T6, running on battery, has not changed much. The same could be observed in the XR-E Q5 model with the same power supply. Thanks to this, it can be understood that the driver of the diodes in question is optimally configured to work with lithium-ion batteries.
Flashlights powered by alkaline batteries, during operation, gradually reduced the flow of light. Most likely, this was due to the fact that it is very difficult for drivers to stabilize the current from AAA cells due to the batteries' inability to deliver the required current value. On a model with a more energy-intensive XM-L T6 diode, the change in brightness is much more noticeable than on the XR-E Q5.
(gallery)images/tech/fonar(/gallery)
Further research
Meanwhile, the test continued, and at the 89th minute, the XM-L T6 flashlight, powered by a battery, suddenly turned off. A very good result, considering that this model always gave out maximum brightness: until the battery was completely discharged, the light flux remained almost at the same level.
The XR-E Q5, powered by batteries, produced a steady stream of light for 3 hours until the end of the test. The diode driver worked with the greatest efficiency: the light flux almost did not lose its brightness level during this time.
The remaining flashlight, the XR-E Q5 on AAA batteries, gave out a weak stream of light by the end of the test, but did not go into low brightness mode.
Conclusions from the test results
The brightest throughout the work remained the first flashlight, XM-L T6 on a lithium-ion battery. This model is excellent if you need very bright light. But do not forget about additional power sources and the ability of the flashlight to turn off completely.
For most users, the battery-powered XR-E Q5 is better. With enough light, the flashlight lasts much longer, and the zoom optics make it more versatile: you can take it with you for fishing, hiking or traveling.
The interest of large companies in reducing energy costs makes them think about redistributing the budget for lighting fixtures. CREE LEDs can be a good help for the widespread introduction of economical and durable lighting sources.
Description
The American company CREE has been actively engaged in the research and production of semiconductor lighting products since 1987, and is currently one of the largest manufacturers of high-power LEDs in the world.
CREE LEDs are produced using the technology of growing an emitting structure on a silicon carbide crystal, which at one time became an innovative breakthrough for the company (previously known production methods involved the use of sapphire). This approach made it possible not only to reduce the cost of production, but also to reduce the thermal resistance of the substrate.
Application
CREE LEDs can be used primarily where high brightness is required with minimal energy consumption: railway transport, automotive industry, street lighting in large cities, etc.
Classification
In general, CREE LEDs can be divided into two groups: powerful called XLamp and super-bright - High-Brightness.
XLamp LEDs are divided into the following subgroups:
In the XT-E family, there is a modification XT-E High-Voltage White, designed to operate at an increased supply voltage (48 V). Its power is 3.5 W and it can serve as a replacement for, for example, 48-volt halogen lamps.
Below is a range of the most common XLamp LEDs:
Super-bright High-Brightness LEDs are divided into the following groups:
The appearance of the High-Brightness LEDs is shown in the figure below:
CREE fakes
Cree's success has led to the emergence of a large number of counterfeits of its products on the market. The technical characteristics of such copies are noticeably inferior to the original:
All this leads to the fact that the number of operating hours is reduced by an order of magnitude (15-20 thousand hours against the original 50-100 thousand).
The photo below shows for comparison the original CREE XM-L and a fake from the Chinese company Latticebright, which has received quite a lot of “fame” in fake CREE LEDs.
Visually, you can immediately pay attention to the fact that the size of the fake crystal is smaller than the original one. Also, the original conductive tracks are recessed inside the circuit board, so they are not so noticeable.
In the photo above: the original CREE XP-E is on the left, the fake is on the right. The original can be seen inside the lens recesses that the copy does not have. Again, CREE has a larger die size.
The video below demonstrates the disassembly of a headlight with a fake XM-L2 LED and the subsequent visual comparison with the original - a noticeable difference in the size of the case and crystal:
The photo below clearly shows the light spots of the original (right) and fake LEDs:
Connection
CREE LEDs require a 9-12V (typical) power supply, although higher voltages can be used, as long as you choose the right current through the diode. Connect the LEDs in parallel using quenching resistors. The switching circuit is shown in the figure below.
The resistor values are calculated based on the source voltage and the current consumed by the LED.
Sequential connection of high-power LEDs leads to an uneven distribution of voltage across them and, accordingly, uneven wear, resulting in failure of the entire circuit.
Pros and cons of CREE LEDs
The main advantages of LEDs are their low power consumption and long service life - the manufacturer guarantees 100,000 hours of operation, which is 50 life cycles of a conventional incandescent lamp (or about 5 for a fluorescent lamp).
Of the minuses, the high cost of LED lamps can be noted - with a power of 45 W, their cost is from 2000 rubles without taking into account the cost of the power supply, despite the fact that similar lamps on fluorescent lamps cost from 400 to 700 rubles. Although it should be noted that in terms of price / quality ratio, CREE LEDs have no analogues.
Another disadvantage of LEDs is the specific nature of the spectrum of their glow, which is unpleasant for some people. This drawback is complemented by the fact that they give directional radiation, that is, to obtain the usual illumination in the room, more lamps will be required than with traditional light sources.
The third disadvantage is that for the stable operation of LED lamps, power and cooling sources are required, the cost of which is comparable to the cost of the lamps themselves. Thus, the payback period of LED technology is about several years.
Comparison of CREE LEDs
Below is a comparison table of some models of XP LED families (power 5 W for XP-G2 and 10 W for XP-L) and XPH35 (power 13 W). The comparison took into account relative dimensions, maximum luminous flux and relative cost.
There is also a luminous flux comparison chart for the most popular LEDs of the XM, XP, XR series:
CREE LED assemblies and strips
In addition to discrete LEDs, CREE manufactures assemblies and strips.
LED assembly is the integration of several crystals into one package to increase the power and intensity of radiation. Typical representatives of this class are shown below:
The power of such assemblies can reach 32 W (XLamp XHP70) with a luminous flux of 4022 Lm.
CREE LED strips are based on CXA type LEDs, the characteristics of some are shown below:
There is also a second generation LED of this type, labeled CXB. They are characterized by a higher luminous flux/power ratio for the same dimensions.
Summary
The CREE product range is rapidly expanding - a few years ago the XLamp lineup was several times smaller. This suggests that the company's products are in great demand, and the scale of counterfeiting may underline this. With economy and quality at an affordable price, CREE products promise to be an effective replacement for traditional lighting sources in the future.
Today, the American company Cree is the world leader in the production of high-power LEDs that have been able to replace conventional incandescent lamps in most lighting fixtures. The range of products is constantly updated. Due to the quality, efficiency and reasonable cost, the products of this company are an excellent replacement for traditional and familiar lighting sources.
Application
Cree LEDs are used primarily where it is necessary to obtain the highest brightness at a lower energy cost. So, they found their application:
Classification
All LEDs produced by the American company Cree are divided into two fairly extensive groups:
In turn, each of the listed groups has certain subgroups that differ in characteristics, case type and coding. As new developments are introduced into mass production, the number of subgroups increases accordingly. So, for example, in 2012, powerful Cree XM L2 LEDs began to be produced. They are released on the platform of a new modification of silicon carbide, have a 20% increased brightness and light output. Power and current consumption remained unchanged. In other words, this company was able to create a more efficient device, while maintaining the level of energy consumed. The model is used to create directional lighting. Also a well-known representative of the first generation XM-L is the powerful Cree T6 WC LED. With high technical performance, it is an excellent option for lighting products.
Powerful Cree LEDs
This group is designed for currents that exceed 350 mA. Such LEDs are widely used in almost all areas of life, replacing gas discharge lamps and incandescent lamps.
There are quite a few models of such devices. This LED is Cree T6, XM, XP, XM1, XM12 and so on. They differ from each other in brightness, efficiency, luminous flux directivity, color parameters and other characteristics.
To choose the most powerful Cree LED, consider their varieties.
Main subgroups
Powerful Cree LEDs are divided into the following subgroups:
Super bright LEDs
High-Brightness LEDs have been developed for high quality billboards and full color video screens, backlighting, decorative and architectural lighting. Their operating current of this product is from 30 to 50 mA.
Subgroups
High-Brightness LEDs are divided into the following subgroups:
Characteristics of diodes
Before mounting the diodes on the board or installing them in a lamp or lantern, they are binned. This concept means sorting by the main parameters: by brightness, color temperature (warm, cold, neutral), as well as for color semiconductors by wavelength. With a bin, you can classify a diode and determine whether it is suitable for a particular purpose.
Brightness options are considered the most interesting feature for users. Depending on which group of diodes the Cree XM L and XP-G LED belongs to, XR-E is studied at different current strengths.
Let's look at some of the most common encodings.
XM L (at 700 mA) | XM 1, XP, XR, XM 12 (at 350 mA) |
|||||||
Brightness bin | ||||||||
300 to 320 Lumens | 280 to 300 Lumens | 260 to 280 Lumens | 87.4 to 93.9 Lumens | 93.9-100 Lumens | 100 to 107 Lumens | 107 to 114 Lumens | 114 to 122 Lumens |
|
If you need a bright one, then you can stop your choice on T5 or Q5 (this is an average). If you need high power, then XM l T6 or U2 LEDs are suitable, while the latter will be the brightest Cree LED.
In addition to brightness, the manufacturer marks its products with a tint bin. The most common are neutral, warm, cold and natural shades.
Advantages and disadvantages of Cree LEDs
The main advantages of these products include their low power consumption and a fairly long service life. So, the manufacturer gives a guarantee for 100 thousand hours of work, which is about 50 life cycles of a simple incandescent lamp or 5 cycles for a fluorescent lamp.
Among the shortcomings, one can single out a rather high price for LED lamps. So, with a power of 45 W, they cost more than 2000 rubles (not including the cost of the power supply). At the same time, the price for the same lamps on fluorescent lamps is from 400 to 700 rubles. Although it is worth noting that in terms of price / quality ratio, products such as Cree LEDs have no analogues.
Also, the disadvantages of such LEDs include a rather specific spectrum of luminescence, which is unpleasant for some people. This minus is complemented by the fact that they have directional radiation, which means that in order to get the usual illumination in the room, it will be necessary to install more lamps than when using traditional and familiar lighting sources.
And another drawback is that to ensure the stability of the LED lamps, a power source and cooling are needed, the price of which can be compared with the cost of the lamps themselves. Based on this, the payback period of such LED technology can reach several years.