Lighting Knowledge

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Lighting Knowledge

Types of lighting

Direct-indirect lighting, diffuse lighting, semi-indirect lighting, indirect lighting, semi-direct lighting, direct lighting

Light Failure

In the use of the light source, over time, the luminous flux continues to diminish in the process of becoming light failure.

Light

Light is a kind of radiation that can be observed by human eyes, and it is proved by experiments that light is electromagnetic radiation, and the wavelength of this part of electromagnetic wave ranges from about 0.77 micrometers of red light to 0.39 micrometers of violet light. Electromagnetic waves with wavelengths above 0.77 microns and up to about 1,000 microns are called “infrared”. Waves with wavelengths of 0.39 microns or less to 0.04 microns or less are called “ultraviolet”. Infrared and ultraviolet rays do not cause vision, but the presence of such luminous objects can be measured and detected using optical instruments or photographic methods. Therefore, the concept of light in optics can also be extended to infrared and ultraviolet, and even X-rays are considered light, while the visible spectrum is only a part of the electromagnetic spectrum.

Luminous flux (Lm)

Luminous fux (luminous fux) refers to the radiant power perceived by the human eye, which is equal to the product of the radiant energy of a certain wavelength and the relative visibility of that wavelength per unit time. Because the human eye to different wavelengths of light relative visibility is different, so different wavelengths of light radiation power is equal, its luminous flux is not equal.

Light source efficiency (Lm/W)

Light source in a unit of time to the surrounding space radiated out and make the human eye produce the energy of light perception
Calculation formula: Ф into = 683P into the V into the
Where Ф into the wavelength into the luminous flux, lumens (lm).
P into a wavelength into the radiant flux (energy emitted by the radiation source in a unit of time, in units of W); V into the wavelength into the spectral luminous efficiency.
683-maximum spectral efficiency, for bright vision, in the entry = 555nm, the value of 6831m/W. Such as multi-color light and its luminous flux for the sum of monochromatic light, that is, into the n = Ф into the 1 + Ф into the 2 + Ф into the 3 +… =Km>[P into V into]

Luminous intensity (Cd)

Luminous intensity (Luminous intensity), in photometry, referred to as light intensity or luminosity. Used to indicate the light source in a given direction on the unit stereo angle within the luminous flux of physical quantities, the international unit of candela, symbol: cd, formerly known as candlelight, branch light.

Illumination (Lx)

Light intensity is a physical term for the luminous flux of visible light received per unit area. It is referred to as illuminance and has the unit lux (Lux or lx). A quantity used to indicate the intensity of light and the extent to which an object’s surface area is illuminated.

Color Temperature (K)

Color temperature is a unit of measurement that indicates the color component contained in light. Theoretically, blackbody temperature refers to the color of an absolute blackbody after it has been heated from absolute zero (-273°C). After being heated, a blackbody gradually changes from black to red, turns yellow, whitens, and finally emits blue light. When heated to a certain temperature, the spectral composition of the light emitted by the blackbody, known as the temperature of the color temperature, the unit of measurement for the “K” (Kelvin)

Color rendering

Color rendering refers to the property that light sources of different spectra present different colors when they illuminate objects of the same color. The color rendering index (Ra) is usually used to indicate the color rendering of a light source. The higher the color rendering index of a light source, the better its color rendering performance.

Concept of Glare

Glare (Dazzle) refers to the visual conditions in the field of view due to inappropriate brightness distribution, or extreme brightness contrast in space or time, so as to cause visual discomfort and reduce the visibility of objects. The visual field produces a bright sensation that the human eye cannot adapt to, which may cause aversion, discomfort or even loss of visual acuity, excessive brightness in a localized area of the visual field or excessive brightness changes before and after.

Four factors affecting glare

1:Luminaire brightness
2:The length of the room and the height of the lamps and lanterns installed (i.e., distance to height ratio)
3:The level of visual adaptation expressed by the average horizontal illuminance
4:Type of luminaire, such as whether the luminaire is side-illuminated, etc.

Brightness (Cd/M2)

The luminous intensity per unit area of a luminous body in the direction of the line of sight.
Calculation formula: As a result of a luminescent body in the retina imaging formed by the visual sensory and retinal illuminance of the object image is directly proportional to the illuminance of the object image of the larger, we feel the brighter; and the illuminance of the object image and the luminous body in the direction of the line of sight of the projection area inversely proportional to the luminous intensity of the luminous body in the direction of the line of sight is directly proportional to the intensity of the luminous body, there are: La = la / (Scosa)
Where La – luminous body along the a direction of the surface brightness (cd/m2); la – luminous body along the a direction of the luminous intensity (cd).
Scosa – luminous body in the direction of the line of sight on the projected surface (m2); in all the light metrics, brightness is the only direct cause of the eye visual sensory quantities.

Relationship between color temperature and illuminance

Relationship between luminous flux, light intensity, illuminance, and brightness

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