Light sources: what shines for us. Natural light sources: examples

Light always surrounds us in nature. Both sunlight, moonlight, and starlight are the most important sources of light to human life. But also, due to the need for additional light, people learned to create light on their own. Understanding the fundamental difference between natural and artificial light is the starting point in describing natural and artificial light sources. Natural light sources exist in nature and are beyond the control of humans. They include sunlight, moonlight, starlight, various plant and animal sources, radioluminescence, and, of course, fire.

Artificial light sources can be controlled by people. Examples of such sources- flames from burning logs, flames from an oil or gas burner, electric lamps, light from photochemical reactions, and various other reactions, such as light from reactions with explosives.
Because of their obvious advantages in terms of availability, safety, cleanliness, and remote control, electric lamps have replaced almost all other artificial sources of lighting in human life. However, since the energy required to operate such artificial light sources is provided mainly by the consumption of natural resources, we come to the conclusion that it is necessary to use natural light sources to the maximum extent possible.

The exploitation of natural light sources remains one of the biggest challenges in lighting.

Designers and architects put great effort into making maximum use of these types of light sources.

Do you know what characteristics they have? You can learn everything about them from our article.

And LED sources of ultraviolet radiation can be read. Try to figure out what areas such sources are used in?

From a practical point of view, light sources can be classified in terms of qualities of the light they produce. These qualities are critical to the lighting result and should be the first consideration when choosing a lighting source.

The most natural light comes from the sun, and moonlight is also natural. Its origin makes it absolutely pure and it does not consume natural resources. At the same time, artificial sources usually require the consumption of natural resources such as fossil fuels to convert stored energy into light energy. Electric lighting, on the one hand, is superior in all respects to ordinary flames from the combustion of wood, gas, oil, but is also a source of pollution. At the same time, electricity can be obtained from natural energy sources such as wind, hydro, geothermal and solar energy.
The operating principle of an electric incandescent lamp determines almost all parameters of the light created by such a lamp. In general, incandescent light bulbs produce light using the incandescent principle, which heats the metal until it glows.
At the same time, most other types of lamps emit light through a complex system of chemical reactions, during which electrical energy is converted into light energy.

In this case, the release of thermal energy is always a side effect.

These processes usually occur in such lamps in relation to the generated light more efficiently than in incandescent lamps - due to complexity and other limitations. For example, a fluorescent lamp generates light by applying electrical voltage to a gas, which in turn emits ultraviolet radiation, which is finally converted into visible light by a special substance that provides the necessary glow. This process generates light for approximately 400 percent more efficient than is the case with conventional incandescent lamps.

LIGHT SOURCES. LIGHTS

Light source– a device in which some type of energy is converted into optical radiation. There are 2 types of optical radiation: thermal and luminescent.

Thermal optical radiation occurs when bodies heat up. Action is based on this principle incandescent lamps (LN) And halogen incandescent lamps (GLN).

Halogen incandescent lamps, in addition to the filament body in the glass bulb, contain halogens concentrated on its walls. For example, iodine, evaporating from the walls, covers the filament and thereby prevents its destruction.

Incandescent lamps have an extremely simple switching circuit; their operation is practically not affected by environmental conditions. But they have very low efficiency. (only 3%), color different from natural light and a relatively short service life - up to 1000 hours.

Compared to conventional incandescent lamps, halogen lamps have a more stable luminous flux over time and an increased service life. They are recommended for use in cases where the required lamp power is 1000 W or more, as well as in rooms with increased requirements for color rendering when it is impossible to use fluorescent lamps.

Luminescent optical radiation is created in gas-discharge lamps as a result of an electric discharge in gases, vapors or their mixtures, while a special substance glows - a phosphor located on the inner walls of the lamp.

There are different types of fluorescent lamps low pressure:

LL – fluorescent lamp;

LB – white light lamp;

LD – daylight;

LDC – daylight with improved color rendering;

LE – close in spectrum to sunlight;

and lamps high pressure (arc):

DRL – arc mercury;

DRI – mercury arc with radiating additives;

DNaT – arc sodium tubular;

DKsT – arc xenon tubular;

DRIMGL – arc mercury with radiating additives, metal halide, etc.

Fluorescent lamps are more economical, they have a longer service life (6-14 thousand hours), they create uniform illumination in the field of view, are not accompanied by thermal radiation, and their emission spectrum is close to the spectrum of natural light.

The disadvantages of such lamps are:

presence of ballasts;

stroboscopic effect;

high sensitivity to temperature conditions: the best conditions correspond to 15-40 0 C; when the temperature drops to 0 0 C, the amount of emitted light decreases by 2 times and the conditions for igniting low-pressure lamps sharply worsen. That's why Low pressure fluorescent lamps are not used on construction sites.

GOST 12.1.046-85 (Lighting standards for construction sites) gives the following recommendations for the use of light sources:

a) to perform external construction and installation work, the following lamps must be used:

LN with a platform width of up to 20 m;

DRL, DNAT – 20-150 m;

DRI – 150-300 m;

DKsT, DKsSh with a site width of over 300 m;

b) LN lamps must be used to carry out construction and installation work indoors.

In administrative premises it is necessary to use only LL lamps.

The leader in the global production of light sources is a Canadian companyVertek. One lampVertekable to illuminate an area of ​​up to 20 hectares.

Lamps– these are lighting devices that redistribute the light of the source within large (up to 4¶) solid angles.

One or more light sources can be installed in luminaires.

The correct choice of lighting characteristics of the lamp guarantees the quality of lighting with the minimum required power of the lighting installation.

The most important lighting characteristic of a lamp is its light distribution, which is defined:

a) luminous intensity curve;

b) light distribution coefficient;

c) form factor.

Light intensity curves are lines of equal luminous intensity drawn in polar coordinates in the meridional plane. Typically, these curves are plotted for a conventional light source with a luminous flux of 1000 lm. Types of luminous intensity curves: concentrated, broad, cosine, sine, etc.

Light distribution coefficient (K With ) equal to the ratio of the luminous flux directed to the lower hemisphere (F l. n.) to the total luminous flux of the lamp (F l.):

K s = F l.n. /F l. .

According to the light distribution coefficient, all lamps are divided into 5 classes:

P(direct light): Kc more than 80%;

N(mainly direct light): Ks = 60-80%;

R(scattered light): K s = 40-60%;

IN(mainly reflected light): Kc = 20-40%

ABOUT(reflected light): Kc less than 20%.

Class P luminaires are used mainly for lighting industrial premises and construction sites, class H - for lighting administrative and laboratory premises. Lamps of classes P, B, O are used when there are special requirements for the quality of lighting. Reflected light luminaires are used in industrial and public spaces with light polished surfaces of walls and ceilings, where the reflection coefficient ρ > 0.3.

Shape factor (K f ) is equal to the ratio of the maximum luminous intensity in the meridional plane to the conditional arithmetic mean value of luminous intensity:

K f = I max /I avg.

The installation of luminaires must provide safe and convenient access to them for maintenance.

By degree of protection you from dust, moisture and explosion luminaires are classified as follows:

CLASSIFICATION OF LUMINAIRES

BY PROTECTION BY PROTECTION BY PROTECTION

FROM DUST FROM EXPLOSION FROM MOISTURE

Unprotected Increased Explosive Resistance - Unprotected

reliability permeable

Open-Closed Splash-proof

Jet-proof

Dustproof

Waterproof

Fully Partially washable

Dustproof Sealed

Fully Partially

Open The lamps do not have any dust protection.

IN blocked luminaires, the ingress of dust into the luminaire is limited by the non-sealed light-transmitting shell.

IN dustproof In lamps, the penetration of dust inside is difficult, but is not excluded in quantities that do not interfere with their satisfactory operation.

IN completely dustproof lamps are provided with dust protection for both current-carrying parts and the lamp bulb, and in partially dustproof– only live parts.

IN splash-proof lamps, it is excluded that live parts and the lamp bulb will be exposed to drops and splashes falling at an angle with the vertical of no more than 45 0 .

Jet-proof the design provides protection when the lamp is doused with a stream of water from any direction.

Waterproof the design must ensure protection of live parts and the lamp bulb from water ingress when the lamp is immersed in water for a limited time, and hermetically sealed– when immersed for an unlimited period of time.

Explosionproof the design must prevent the occurrence of an explosion when the luminaire body is exposed to the environment. This is achieved by limiting the maximum permissible temperature of its surface. At the same time, the design of the lamp

prevents the spread of an explosion that occurs inside to the external environment.

Using lamps increased reliability against explosion does not exclude the possibility of an explosion occurring inside the lamp being transmitted to the external environment, but reduces this probability to a minimum by using a special explosion-proof cartridge.

The selected luminaire must satisfy the following requirements:

comply with environmental conditions;

provide the necessary light distribution and eliminate glare;

be economical.

Environmental conditions determine the design of the lamp.

A special type of lamps are slot fibers, used for lighting explosion- and fire-hazardous industries. The luminaires consist of an optical system, a group of high-power light sources (20-40 kW) located outdoors, and a light guide channel up to 100 m long with a diameter of up to 1.5 m.

Widely used on construction sites spotlights– lighting devices that redistribute light within small solid angles and provide angular concentration of the light flux.

For lighting, for example, halogen spotlights of the IO-02, ISU-01 type and spotlights for incandescent lamps - PZM, NO are used.

Advantages of spotlights:

efficiency,

favorable ratio of vertical and horizontal illumination for three-dimensional vision,

less congestion of the territory with poles and overhead wiring,

ease of maintenance.

Disadvantages: the need for measures to reduce glare and eliminate shadows.

CALCULATION OF ARTIFICIAL LIGHTING

Design of artificial lighting begins during development construction organization projects And work project.

Roughly identify the categories of visual work in various areas of the construction site and draw up a map of the location of construction sites according to illumination standards (zoning).

Pre-installed source data:

the lighting system is determined;

select the type of light source (lamp);

the type of lamps is selected taking into account air pollution and in accordance with explosion and fire safety requirements;

the distribution of lamps is carried out and their quantity is determined; lamps can be arranged in rows, in a checkerboard pattern, or in a diamond pattern;

lighting standards in the workplace are determined.

Lighting calculations are carried out using the following methods.

1 method. To calculate the overall uniform illumination with a horizontal working surface, taking into account the luminous flux reflected from the ceiling and walls, it is used "light flux method".

The luminous flux of a lamp F l (lm) with incandescent lamps or the luminous flux of a group of lamp lamps with fluorescent lamps is calculated by the formula:

where E n – normalized minimum illumination, lux;

S – area of ​​the illuminated room, m2;

Z = E av / E min = 1.1…1.5 – minimum illumination coefficient;

K – safety factor equal to 1.4...1.8;

N – number of lamps (incandescent lamps) in the room;

Η – coefficient of utilization of the luminous flux of lamps, depending on the index (indicator) of the room I and the reflection coefficients of the ceiling ρ p, walls ρ st and floor ρ r.

The room indicator is determined by the formula:

where A and B are the length and width of the room, respectively, m;

Нр – height of luminaires above the design surface, m.

Based on the value of the luminous flux, select the nearest standard LN lamp or fluorescent lamps of the lamp (and their required quantity) and determine the electrical power of the entire lighting system.

Method 2. To calculate general localized and local lighting, lighting of inclined planes, as well as to check the calculation of uniform general lighting, when the reflected luminous flux can be neglected, use "point method".

The essence of the method is to determine the illumination of a point by the luminous flux incident from the light emitter. In this case, the surface illumination is equal to:

where I a is the luminous intensity in the direction from the source to a given point

working surface, cd;

α is the angle that determines the direction of the light intensity in the calculated

point (the angle between the normal to the working surface and the

facing the light source), 0 .

When calculating the illumination created at a point by several lamps, the illumination from each of them is calculated, and then the arithmetic sum of the illumination is found.

Method 3. For approximate calculations it is used "power density method". This method allows you to determine the power of each lamp to create standardized illumination in the room.

In all cases when it is impossible to place conventional lamps above the illuminated surface to illuminate open spaces with an area of ​​more than 5000 m2, use spotlight lighting.

When calculating floodlighting, a standardized illumination and a safety factor are selected that takes into account the aging and dustiness of the lamps. Then the type of floodlight is selected, the smallest height for its installation from the conditions of minimal glare, the arrangement of masts and the angles of inclination of the optical axis of the floodlights in the vertical and horizontal planes are designed.

In accordance with the requirements of GOST 12.1.046-85, the following types of floodlights are recommended for lighting construction sites and areas: PSM, PZR, PZS, PKN, ISU, OUKsN, SKsN.

SNiP 05/23/95. Natural and artificial lighting.

A reference book for electrical lighting design. Ed. G.M. Knorring. M., 1976.

Labor protection in mechanical engineering. Ed. E.Ya.Yudina and S.V. Belova. M., 1983.

There are natural, or natural, light sources. This is the Sun, stars, atmospheric electrical discharges (for example, lightning). The moon is also considered a light source, although it would be more correct to classify it as a light reflector, since it does not emit light itself, but only reflects the sun's rays falling on it. Natural light sources exist in nature independently of humans.

Light sources. Luminescent pump: 1 - contacts; 2 - a glass tube, coated on the inside with phosphor and filled with an inert gas. Incandescent lamp: 1 - cylinder; 2 - filament; 3 - holder; 4 - base. Mercury gas discharge lamp.

An electric arc can also be a source of light.

But there are many light sources created by man. These are bodies, substances and devices in which energy of any kind, under certain conditions that depend on a person, is converted into light. The simplest and oldest of them are a fire, a torch, a torch. In the ancient world (Egypt, Rome, Greece) vessels filled with animal fat were used as lamps. A wick (a piece of rope or a rag twisted into a rope) was lowered into the vessel, which was saturated with fat and burned quite brightly.

Subsequently, until the end of the 19th century, the main sources of light were candles, oil and kerosene lamps, and gas lanterns. Many of them (for example, candles and kerosene lamps) have survived to this day. All these light sources are based on the combustion of flammable substances, which is why they are also called thermal. In such sources, light is emitted by tiny, hot solid carbon particles. Their luminous efficiency is very low - only about 1 lm/W (the theoretical limit for a white light source is about 250 lm/W).

The greatest invention in the field of lighting was the creation in 1872 by Russian scientist A. N. Lodygin of an electric incandescent lamp. Lodygin's lamp was a glass vessel with a carbon rod placed inside it; the air was pumped out from the vessel. When an electric current was passed through the rod, the rod heated up and began to glow. In 1873 - 1874 A. N. Lodygin conducted experiments on electric lighting of ships, enterprises, streets, and houses. In 1879, the American inventor T. A. Edison created an incandescent lamp with a carbon filament, convenient for industrial production. Since 1909, incandescent lamps with a zigzag tungsten wire (incandescent filament) began to be used, and after 3–4 years the tungsten filament began to be manufactured in the form of a spiral. At the same time, the first incandescent lamps filled with inert gas (argon, krypton) appeared, which significantly increased their service life. Since the beginning of the 20th century. Electric incandescent lamps, due to their efficiency and ease of use, are beginning to quickly and widely replace other light sources based on the combustion of flammable substances. Currently, incandescent lamps have become the most widespread light sources.

All the numerous varieties of incandescent lamps (more than 2000) consist of the same parts, differing in size and shape. The structure of a typical incandescent lamp is shown in the figure. Inside a glass flask from which air has been evacuated, a tungsten wire spiral (incandescent body) is fixed to a glass or ceramic rod using holders made of molybdenum wire. The ends of the spiral are attached to the inputs. During the assembly process, air is pumped out of the lamp bulb through the stem, after which it is filled with inert gas and the stem is welded. For mounting in a socket and connecting to the electrical network, the lamp is equipped with a base to which the inputs are connected.

Incandescent lamps are distinguished by areas of application (general-purpose lighting, for car headlights, projection, floodlights, etc.); according to the shape of the filament body (with a flat spiral, bi-spiral, etc.); by flask size (miniature, small-sized, normal, large-sized). For example, for subminiature lamps, the bulb length is less than 10 mm and the diameter is less than 6 mm; for large-sized lamps, the bulb length reaches 175 mm or more, and the diameter is more than 80 mm. Incandescent lamps are manufactured for voltages from fractions to hundreds of volts, with a power of up to tens of kilowatts. The service life of incandescent lamps is from 5 to 1000 hours. Luminous efficiency depends on the design of the lamp, voltage, power and burning time and is 10–35 lm/W.

In 1876, Russian engineer P. N. Yablochkov invented an alternating current carbon arc lamp. This invention marked the beginning of the practical use of electric charge for lighting purposes. The system of electric lighting using alternating current using arc lamps - “Russian light”, created by P. N. Yablochkov, was demonstrated at the World Exhibition in Paris in 1878 and enjoyed exceptional success; Soon, companies were founded in France, Great Britain, and the USA to use it.

Since the 30s. XX century Gas-discharge light sources are becoming widespread, which use radiation generated by an electrical discharge in inert gases or vapors of various metals, especially mercury and sodium. The first samples of mercury lamps in the USSR were manufactured in 1927, and sodium lamps in 1935.

Gas-discharge light sources are a glass, ceramic or metal (with a transparent window) shell of cylindrical, spherical or other shape, containing gas and sometimes a certain amount of metal vapor or other substances. Electrodes are soldered into the shell, between which an electric discharge occurs.

The most widely used for lighting buildings and structures are fluorescent lamps, in which the ultraviolet radiation of an electrical discharge in mercury vapor is converted using a special substance - a phosphor - into visible, i.e., light radiation. The luminous output during the service life of fluorescent lamps is several times greater than that of incandescent lamps for the same purpose. Among such light sources, mercury fluorescent lamps are the most widespread. Such a lamp is made in the form of a glass tube (see figure) with a layer of phosphor applied to its inner surface. Tungsten spiral electrodes are soldered into the tube at both ends to excite an electrical discharge. A drop of mercury and a little inert gas (argon, neon, etc.) are introduced into the tube, which increases the service life and improves the conditions for the occurrence of an electric discharge. When the lamp is connected to an alternating current source, an electric current arises between the electrodes of the lamp, exciting the ultraviolet glow of mercury vapor, which in turn causes the phosphor layer of the lamp to glow. The luminous efficiency of fluorescent lamps reaches 75–80 lm/W. Their power ranges from 4 to 200 W. The service life exceeds 10 thousand hours. The length of fluorescent lamps ranges from 130 to 2440 mm. Based on the shape of the tube, lamps can be straight, V-shaped, W-shaped, ring-shaped, or candle-shaped. Such lamps are widely used for indoor lighting, in photocopiers, in illuminated advertising, etc. For highway lighting, sodium lamps with a luminous efficiency of up to 140 lm/W are used. Streets are usually illuminated with mercury lamps with a luminous efficiency of 80–95 lm/W. In addition to high luminous efficiency, gas-discharge light sources are characterized by simplicity and reliability in operation.

A completely new type of light source is lasers, which produce highly targeted light beams that are exceptionally bright and uniform in color. And the future of lighting lies in LEDs.

Light sources are one of the most popular products. Billions of lamps are produced and consumed annually, a significant share of which are still incandescent and halogen lamps.

The consumption of modern lamps - compact fluorescent and LED - is growing rapidly. The ongoing changes in quality give hope that light sources will become an important tool for the designer, architect, and planner.

About illumination and color temperature of light

A number of lamp parameters determine how applicable they are in a particular project.

Luminous flux determines the amount of light the lamp produces (measured in lumens). A 100 W incandescent lamp installed in a chandelier has a luminous flux of 1200 lm, a 35-watt halogen lamp has a luminous flux of 600 lm, and a 100 W sodium lamp has a luminous flux of 10,000 lm.

Different types of lamps have different luminous efficiency, which determines the efficiency of converting electrical energy into light and, consequently, the different economic efficiency of application. The luminous output of a lamp is measured in lm/W (lighting engineers say “lumens per watt,” meaning that each watt of electricity consumed is “converted” into a certain number of lumens of luminous flux).

Moving from quantity to quality, consider color temperature(T color, unit of measure - degree Kelvin) and color rendering index(Ra). When choosing lamps, the designer must take into account for a particular installation. A comfortable environment greatly depends on whether the light in the room is “warm” or “cool” (the higher the color temperature, the “cooler” the light).

Color rendering is an important parameter that is often forgotten. The more continuous and uniform the spectrum of a lamp, the more visible the colors of objects in its light. The Sun has a continuous spectrum of radiation and the best color rendition, while T color varies from 6000K at noon to 1800K at dawn and sunset. But not all lamps can compare with the Sun.

If from artificial sources thermal radiation continuous spectrum and no problems with color rendering, then discharge lamps, having stripes and lines in their spectrum, greatly distort the colors of objects.

The color rendering index of thermal sources is 100; for bit sources it ranges from 20 to 98. However, the color rendering index does not allow one to draw a conclusion about the nature of color rendering, and can sometimes confuse the designer. Thus, fluorescent lamps and white LEDs have good color rendering (Ra=80), but at the same time they render some colors unsatisfactorily.

Another extreme case is when the color rendering index is more than 90 - in this case, some colors are reproduced unnaturally saturated.

Lamps fail. In addition, the luminous flux of the lamp decreases during operation. Service life is the main operational parameter of light sources.

When designing a lighting installation, we must not forget about maintenance, since frequent replacement of lamps increases the cost of operation and introduces discomfort.

Incandescent lamps

The tungsten coil in the flask is heated by electric current. To reduce the rate of tungsten sputtering and, accordingly, increase the service life of the lamp, the bulb is filled with an inert gas. According to the principle of operation, an incandescent lamp is classified as a thermal light source, i.e., a significant proportion of the energy consumed is spent on thermal and infrared radiation.

Typical luminous efficacy for incandescent lamps is 10–15 lm/W, and the service life rarely exceeds 2000 hours. The advantages of these lamps: low price and quality of light (T color = 2700, Ra = 100). A continuous spectrum qualitatively reproduces the colors of surrounding objects. Incandescent lamps are gradually being replaced by discharge light sources and LED lamps.

Halogen incandescent lamps

The addition of halogens to the bulb of an incandescent lamp and the use of quartz glass made it possible to take a serious step forward, obtaining a new class of light sources - halogen incandescent lamps. The luminous efficiency of modern GLNs is 30 lm/W. The typical color temperature is 3000K and the color rendering index is 100. The “point” shape of the light source with the help of reflectors allows you to control the light beam.

The resulting sparkling light determined the priority of such lamps in interior design, where they took the lead. Another advantage is that the quantity and quality of light from the lamp is constant throughout its service life. Popular are low-voltage “halogen” lamps with a power of 10–75 W with a reflector that focuses the beam at an angle of 10–40°.

The disadvantages of GLN are obvious: low luminous efficiency, short service life (on average 2000–4000 hours), the need to use (for low-voltage) step-down transformers. Where the aesthetic component is more important than the economic one, you have to put up with them.

Fluorescent lamps

Fluorescent lamps (LL) - low-pressure discharge lamps - are a cylindrical tube with electrodes, which is filled with an inert gas and a small amount of mercury. When turned on, an arc discharge occurs in the tube, and the mercury atoms begin to emit visible light and ultraviolet light. The phosphor applied to the walls of the tube emits visible light under the influence of ultraviolet rays.

The basis of the luminous flux of the lamp is the radiation of the phosphor; visible mercury lines make up only a small part. The variety of phosphors (mixtures of phosphors) makes it possible to obtain light sources with different spectral composition, which determines the color temperature and color rendering index.

Fluorescent lamps provide soft, uniform light, but its distribution in space is difficult to control due to the large surface area of ​​the radiation. To operate fluorescent lamps, special ballasts are required. The lamps are durable - service life up to 20,000 hours.

Luminous output and service life have made them the most common light sources in office lighting.

Compact fluorescent lamps

The development of fluorescent lamps led to the creation of compact fluorescent lamps (CFLs). This is a light source similar to a miniature fluorescent lamp, sometimes with a built-in electronic ballast and a threaded base E27 (for direct replacement of incandescent lamps), E14, etc.

The difference lies in the reduced tube diameter and the use of a different type of phosphor. A compact fluorescent lamp can successfully replace incandescent lamps.

High Pressure Discharge Lamps

Recent developments make it possible to use high-pressure discharge lamps for lighting. Metal halide (MHL) are suitable for a number of indicators. These lamps have a burner with emitting additives placed in the outer bulb. The burner contains a certain amount of mercury, halogen (usually iodine) and atoms of chemical elements (Tl, In, Th, Na, Li, etc.).

The combination of emitting additives achieves interesting parameters: high luminous efficiency (up to 100 lm/W), excellent color rendering Ra = 80–98, Tsv range from 3000 K to 6000 K, average service life up to 15,000 hours. To operate these lamps, ballasts and special lamps are required. It is recommended to use these sources to illuminate large areas, high ceilings, and spacious halls.

LED lamps

LEDs, semiconductor light-emitting devices, are called the light sources of the future. If we talk about the current state of “solid-state lighting technology,” we can say that it has come out of its infancy. The achieved characteristics of LEDs (luminous efficiency up to 140 lm/W, Ra=80–95, service life 70,000 hours) have already provided leadership in many areas.

The power range of LED sources, the implementation of different types of sockets in lamps, and lamp control made it possible to quickly meet the growing requirements for light sources. The main advantages of LEDs remain their compact size and control of color parameters (color dynamics).

In ancient times, humanity thought that we could see thanks to tentacle rays that come out of the eyes, as if testing objects by touch. It seems ridiculous and funny. But actually, Where does it come from? There are natural and artificial light sources. Modern ideas say that light is electromagnetic waves or a stream of photons. In fact, light is radiation, but only that part of it that can be perceived by the eye. That is why it is called When light propagates, its wave qualities are revealed. Which we will talk about below.

Light

What is this? To put it bluntly, this is an electromagnetic wave. It is perceived through human eyes. True, there are boundaries of perception - from 380 to 780 nm. At lower levels, there is a stream of ultraviolet radiation, which a person cannot see, but feels. On the skin it appears as a tan. There is also infrared radiation, which only some living organisms can see, and people perceive it as heat.

Light comes in different colors. If you remember the rainbow, it has seven colors. The violet color present in it is formed by a beam of wavelength 380 nm, red - 625, but green - 500, more than violet, but less than red. Many artificial light sources emit white waves. White light occurs when all the other primary colors are mixed - red, orange, yellow, green, cyan, indigo and violet.

Properties

Thanks to experiments, it was possible to establish that light has an electromagnetic nature. Simply put, light is electromagnetic radiation that can be seen.

Light boasts that it has the ability to pass through transparent substances and bodies. Thanks to this, sunlight easily penetrates through the atmosphere to the earth. But at the same time it is refracted. When an opaque body or object meets the path of light, the light is reflected from them. Thus, we accept the reflected color with the eye and see not only the color, but also the shape.

A certain part of the light is absorbed by objects, and they heat up. Light objects do not heat up as much as dark objects because they absorb more light and reflect less. That's why they look dark. The lion's share of information about what surrounds us comes through vision. Thanks to him, we analyze everything. Good vision and a high level of performance are very related to lighting.

Sources

The bodies from which light emanates are the sources of light. There are natural and artificial light sources. The most popular and vital natural source of light is the Sun, namely solar radiation - the radiant flux of a star that reaches the surface of our planet in the form of direct and diffuse light. In natural light, or more precisely in its spectrum, there are ultraviolet rays, which are simply necessary for humans. Diffuse is a characteristic feature of natural lighting. It is beneficial for vision. After we have dealt with many concepts, we can begin to explain what it is - artificial and natural light sources.

Artificial sources

Until the end of the 19th century, the only thing was fire, in all its interpretations. Later, the rapid development of electric light sources began actively. Over almost 130 years of their existence, fire was almost completely replaced - kerosene lamps and candles appeared. They are still used when there is an accident at the station, when the lighting suddenly goes out, for a romantic evening, to create an appropriate atmosphere. On camping trips, when the flashlights have run out, you can light a fire for more extensive illumination.

Is a fire an artificial or natural source of light? It should be sorted out. The flame of burning dry twigs, as well as the flame of a candle, gas burner, and so on, are artificial sources. I would like to note one feature. Artificial light sources can be controlled by people.

Let's think like this: in principle, the fire burns on its own, giving off heat as well. You can warm up next to it, and see friends in the dark sitting opposite and singing with a guitar. It seems like a fire is a natural source of light. He gives his unreflected light, like the Moon. But then the fire begins to go out, and it becomes necessary to add more wood. The more wood, the larger the flame. This means it can be controlled. Moreover, the fire was originally created by the tourists themselves. And artificial sources are those created by man. This suggests a conclusion: a fire is still an artificial source of light.

Technical devices of the most varied structures are also artificial. These are incandescent lamps, spotlights, electric lamps, etc. There are bodies that cannot emit on their own, but emit reflected light, for example, the Moon.

Let's take a closer look at which light sources are natural.

Natural sources

All objects from which natural light flows should be classified as natural sources. They are natural sources of light. It does not matter what kind of wave emission occurs, as a primary or secondary property. Natural light sources play a huge role in the life of all living organisms. Natural sources in nature are not controlled by humans:

• Sunlight.
• Fire, a natural source of light.
• Starlight.
• Glow of various animal and plant organisms.

And this is not the entire list. You can list other natural light sources. Examples: The sun scorching on a July day, stars that can be observed at night and arranged into bizarre constellations, lightning tearing through loose clouds, a comet with a luxurious tail or the aurora, shimmering and causing admiration. Natural light can be seen as insects and some types of fish glistening in the grass, like small grains of gold, swimming importantly almost on the seabed.

Interstellar gas

A rarefied gaseous environment fills the space between the stars. The gas is transparent. The bulk of the interstellar gas is observed closer to the galactic plane. This layer is many hundreds of parsecs thick. The chemical composition is similar to most stars - hydrogen, helium and some heavy particles. Gas is in atomic, molecular and ionized form, all depending on density and temperature. The gas absorbs and in return they give it the available energy. Ultraviolet radiation emanating from hot stars begins to heat the gas. Then the gas itself begins to emit light. A person observes it as a bright nebula.

Bioluminescence

The tricky word refers to the ability of living organisms to glow. This skill is achieved independently or with the help of symbionts. The Greek word bios means life. And the Latin “lumen” means light. Such a talent as creating light does not belong to everyone. This requires specially luminous organs and the possession of a more developed organism. For example, in the photophores of fish, in special organelles in unicellular eukaryotes, in the cytoplasm of bacteria. Let's remember fireflies and some aquatic organisms that live on the bottom of the oceans (deep-sea cuttlefish, radiolaria). Bioluminescence is a product of chemical processes, the energy that is released begins to be released in the form of light. In other words, it is a special type of chemiluminescence.

Radioluminescence

This process is caused by the influence of ionizing radiation. Such chemical compounds that emit gamma and x-rays, alpha, beta particles are used to create a radioluminescent layer in some substances. For example, dyes, which consist of a mixture of zinc sulfide and a substance that emits ionizing radiation, emit light for a long period of time. This period is measured in years and even decades. Such substances are widely used in special paints. They covered the dials of watches and instruments.

Spread of Light

Light does not have the ability to bend around obstacles it encounters on its path. It spreads in a straight line. And nothing else. Therefore, a shadow is formed behind an object that does not have transparent properties. The shadow is not always black. Since scattered and reflected rays of light that come from other objects get there. Artists know this especially well.

Rays of light are not able to pass through a dark barrier. For example, if the Moon is between the Sun and the Earth, solar eclipses occur.

Light sources. "Hot" and "cold"

Consider natural light sources. Examples of warm sources are the Sun. It is not only the main source of light, but also heat. Therefore, in the understanding of humanity, light means heat. Hot lava, which quickly rushes down the slope of the volcano, also releases enormous amounts of heat, but slightly less light.

Everyone has encountered “cold” light in their life. These are fireflies, rotten ones. But the bodies of the owners of such light do not heat up.

Point light source

When studying light phenomena, the concept of a “point source of light” appeared. It is not a discovery that all light sources have their own size. The natural source of light is a star. The sun is a yellow dwarf. There are stars that are much larger, but are perceived by people as point sources of light, because they are located at an enormous distance from our planet.

In conclusion, I would like to mention the natural sources of light in our mortal existence - this is joy and happiness! May they never leave you and illuminate your path in life.