What are the LED Lighting Terms_Part II

Color Rendering Index (CRI)

Refers to the appearance of a target object under a light source compared with the original color under a reference light source (such as daylight), how realistic the performance is the same as the original color

 

Contrast sensitivity (contrastsensitivity)

The ability to detect differences in brightness, if stated qualitatively, it is equal to the reciprocal of the contrast limit

 

Cutoff angle ofa luminaire

Measured from the lowest point, the angle between the first ray of naked light that cannot be seen by the human eye and the vertical line

 

Diffuse reflection

Refers to the process in which the incident light beam is reflected back within a certain angle range

 

Diffused lighting

Refers to an illumination method in which the incident light does not mainly come from a single special direction

 

Diffuser

Refers to a device that can reflect or scatter the light emitted by a light source, usually mainly through diffusion

Direct glare

Glare caused by extremely high brightness, insufficient light source shielding, or high-brightness reflection in the field of view.

 

Directional lighting (directionallighting)

Refers to lighting mainly from a single direction on the work surface or target

 

Disability glare

Refers to the glare that reduces visual function and visibility

 

Discomfort glare

Glare that instructs people to feel uncomfortable

 

Fenestration

Refers to any daylighting method that uses window openings or window opening arrangements (usually controlled by light media) to introduce daylight.

 

Field angle or beam angle (field angle)

On a plane perpendicular to the centerline of the beam, the luminosity is equal to the angle between the two directions of 10% of the maximum luminosity.

 

Floodlight

Refers to a light projector designed to illuminate a scene or object when the lighting requirements of the reference scene or object are much stronger than its background.

 

Flushmounted or recessed luminaire

Refers to a lamp installed in the ceiling (or placed in a wall or other compartment). The opening of the lamp is usually in line with the plane where it is located.

General lighting

Provide a lighting design that shows a substantially uniform distribution of illuminance in all areas.

Glare

There is a sense of light in the visual field that the human eye cannot adapt to, which may cause disgust, discomfort or even loss of clarity

 

Illuminance (luxor foot candle)meter

An instrument that measures illuminance on a flat surface.

 

Intensity

Abbreviation of luminous intensity and radiant intensity

 

inverse-square law

E=I/d2–The illuminance is inversely proportional to the square of the distance and directly proportional to the luminosity

 

Isolux (isofootcandle) line)

Refers to a curve drawn with appropriate coordinates on all points of the same illuminance on the illuminated surface; different isoilluminance lines constitute an isoilluminance diagram.

lamp lumen depreciation factor (LLD)

A multiplier used in lighting calculations to indicate the relationship between the initial illuminance of the tube and the expected minimum illuminance at the end of the use of the tube

 

Lamp shielding angle

Refers to the angle between the light shielding body or the plane of the armor plate and the horizontal plane closest to the tangent direction of the light and the armor plate. Usually the shading angle of the electric lamp is greater than (never less than) the shading angle of the armor plate

 

Lens

A glass or plastic component used in lamps that can change the direction of light or control the distribution of light

 

Light

Radiation energy that can excite the retina to produce visual ability; the visible spectrum of electromagnetic waves ranges from 380 to 770nm (10-9m)

Light loss factor (light loss factor, LLF)

A coefficient used to calculate the magnitude of illuminance under known conditions and over a period of time, which takes into account factors such as temperature, voltage changes, the amount of dust accumulation on the outside of lamps and rooms, the depreciation of electric lamps, and atmospheric conditions. Formerly also known as maintenance factor.

 

Local lighting

Provides illuminance for small areas or local areas of lighting design, which does not provide any more significant general surrounding lighting

 

Localized general lighting

Refers to the use of lamps and lanterns on the work post to provide lighting, usually also includes the surrounding lighting of the work post

 

Louver

A string of reflectors used to shield or absorb unwanted light at a certain angle, usually arranged in geometric shapes

 

Louver shielding angle

Refers to the angle between the horizontal plane of the light shielding body or the shutter and the plane that hides all the equipment in the lamp

 

Louvered ceiling

It belongs to a ceiling type area lighting system, which uses multiple grid-shaped shutters to shield the light source installed on it

 

Lumen calculation method (lumen (or flux) method)

A lighting design program used to determine the relationship between the number and type of electric lamps or lamps, the characteristics of the room, and the average illuminance level of the working surface. It considers both the direct luminous flux and the reflected luminous flux.

Luminaire

Refers to the complete lighting equipment, including one or more electric lights and its accessory equipment

 

Luminaire dust depreciation factor (luminairedirt depreciation factor, LDD)

 

A multiplier used to calculate the illuminance, indicating the relationship between the illuminance of the luminaire when it is clean and new and the illuminance of the luminaire after dust accumulation

 

Lamp efficiency

Refers to the ratio of the luminous flux emitted by the lamp to the luminous flux emitted by the lamp

 

luminance photometric brightness

Refers to the luminosity per unit area of ​​any illuminated surface in a known direction from that direction. All visible objects have some brightness

 

luminance contrast

Refers to the relationship between the brightness of the target object and its direct background brightness

 

luminance difference

Refers to the difference in brightness between the two regions

 

luminance ratio

The ratio of the brightness of the two areas in the field of view

 

luminous ceiling

It belongs to a ceiling type area lighting system, which is composed of a continuous plane that can be penetrated by light. The light source is installed on the top and can be diffused or controlled to change the light emitting method.

luminance efficacy of a Light source

Equal to the total luminous flux emitted by the lamp divided by the total input power, in lumens/watt

 

luminous flux

Refers to the total amount of light emitted by a light source in a certain unit time, generally referred to as light beam, and the unit is lumens

 

luminous intensity

A point light source radiates in a known direction. The luminous flux emitted within a unit solid angle is called candlelight or lumens/solid angle.

 

Lux

SI system of illuminance unit, the illuminance of one lux can be obtained by irradiating a first-class bright beam on a working surface of one square meter

 

Matte surface

Refers to reflection is mainly a diffuse component that can be ignored, see diffusereflection

 

Mercury lamp

Refers to a high-intensity discharge lamp (HID), which is mainly formed by applying mercury to 105Pa (about one atmospheric pressure) to emit light.

 

Mounting height above the work-plane

Refers to the distance from the work surface to the center of the light source of the luminaire, or the distance to the ceiling (referring to hidden luminaires).

 

Point method

Also known as the point-by-point method, it is a lighting design program that uses the lighting brightness data of the lamps to determine the illuminance of the lighting system installed in different locations. The total illuminance at a certain point is equal to the sum of the direct illuminance of the lamp and the illuminance between the surface of the room.

Primary playing area

Refers to the entire competition area where the illuminance level must be maintained

 

Quality of lighting

The measurement of lighting distribution in a visual environment. This term is often used as a positive evaluation to indicate whether all lighting meets the requirements of visual function, visual comfort, ease of viewing, safety, and aesthetics.

 

Reflectance (reflectance of asurface or medium)

Namely DXr/Di, which represents the ratio of reflected luminous flux to incident luminous flux

Reflected glare

Refers to the glare caused by the highly reflective bright light produced by polished objects or smooth objects in the field of view

 

Reflection

Refers to a general term describing the process of incident luminous flux leaving from the illuminated surface or the incident surface of the medium

 

Reflector

Refers to a device that regenerates light flux by reflection

 

Room utilization factor (utilance)

Refers to the ratio of the luminous flux received by the working surface to the luminous flux emitted by the lamp

 

Secondary playing area

Refers to the area between the main competition area and actual obstacles (such as fences)

 

(Shielding angle (of a luminaire))

Refers to the angle between the horizontal line passing through the center of the light source and the first line of naked light that can be seen by the human eye

 

Spotlight

Refers to a lamp with a very narrow beam angle to illuminate a specific area

 

Stray light

Generally refers to light that exceeds the line of sight of the eye’s retina

 

Subjective brightness

Refers to any main attributes related to light perception produced by light perception, including all visual attributes of brightness, illuminance, brightness, dimming or darkness

 

Supplementary lighting

Refers to the lighting that provides additional quality and quantity of illuminance, which cannot be obtained by a general lighting system, and is usually installed for special work needs

 

Surface mounted luminaire

Refers to lamps directly installed on the ceiling

Task lighting

Refers to the direct lighting of a particularly illuminated area or area that provides sufficient illuminance depending on the workplace.

Transmission

P=Xt/Xi; refers to the ratio of the transmitted luminous flux to the incident luminous flux

 

transmittance

Refers to the process in which the luminous flux leaves the illuminated surface or the other side of the incident surface of the medium

 

Tungsten-halogen lamp

Refers to an inflatable tungsten filament incandescent lamp

 

Veiling luminance

Refers to a lighting method that reduces the contrast of retinal images. In the field of vision, you can use this method to change the visual function and brightness of the strong light area

 

Veiling reflection

The use of light curtain diffuse reflection will reduce the contrast of brightness and make the target more unclear

 

Visibility (visibility)

Refers to the quality and state of human vision. Outdoors, it refers to the distance at which the target can be detected by human eyes. Indoors, it refers to the ability to see the actual object clearly in a standard visual environment

 

Visual acuity

A measure of visual ability that refers to the clarity of recognizable targets

Visual angle

Refers to the arc angle from the observation point to the target or specific object, usually measured in arc

 

Visual field

If the head and eyes are kept fixed, the trajectory range of the target or point in space that the human eye can see

 

Visual perception

An explanation that refers to the transmission of real external impressions from the retina to the brain when the human eye sees it

 

Visual performance

Taking speed and accuracy into consideration, a quantitative assessment of the illuminance of the workplace

 

Visual surround

In addition to the part of the field of vision other than the job

 

Visual task

Traditionally refers to the visual conditions necessary to complete a given task, under which all relevant targets and work details can be seen.

 

work-plane

Usually refers to the place where the work is completed, where the illuminance is standardized and measured. Unless otherwise stated, it is generally assumed to be on a horizontal plane 0.76 meters (30 inches) above the floor.