LED Lighting Terminology
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception. Similarly, luminous emittance is the luminous flux per unit area emitted from a surface. Luminous emittance is also known as luminous exitance.
In SI derived units these are measured in lux (lx) or lumens per square metre (cd * sr * m – 2). In the CGS system, the unit of illuminance is the phot, which is equal to 10,000 lux. The foot-candle is a non-metric unit of illuminance that is used in photography.
Illuminance was formerly often called brightness, but this leads to confusion with other uses of the word. “Brightness” should never be used for quantitative description, but only for non quantitative references to physiological sensations and perceptions of light.
The human eye is capable of seeing somewhat more than a 2 trillion-fold range: The presence of white objects is somewhat discernible under starlight, at 5 × 10– 5 lux, while at the bright end, it is possible to read large text at 108 lux, or about 1,000 times that of direct sunlight, although this can be very uncomfortable and cause long-lasting after images.
Colour temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, horticulture, and other fields. The colour temperature of a light source is the temperature of an ideal black body radiator that radiates light of comparable hue to that of the light source. Colour temperature is conventionally stated in the unit of absolute temperature, the Kelvin, having the unit symbol K.
Color temperatures over 5,000K are called cool colours (bluish white), while lower colour temperatures (2,700–3,000 K) are called warm colours (yellowish white through red). This relation, however, is a psychological one in contrast to the physical relation implied by Wien’s displacement law, according to which the spectral peak is shifted towards shorter wavelengths (resulting in a more bluish white) for higher temperatures.
Unit: x, y
The chromaticity diagram illustrates a number of interesting properties of the CIE XYZ color space:
The diagram represents all of the chromaticities visible to the average person. These are shown in color and this region is called thegamut of human vision. The gamut of all visible chromaticities on the CIE plot is the tongue-shaped or horseshoe-shaped figure shown in color. The curved edge of the gamut is called the spectral locus and corresponds to monochromatic light (each point representing a pure hue of a single wavelength), with wavelengths listed in nanometers. The straight edge on the lower part of the gamut is called the line of purples. These colors, although they are on the border of the gamut, have no counterpart in monochromatic light. Less saturated colors appear in the interior of the figure with white at the center.
It is seen that all visible chromaticities correspond to non-negative values of x, y, and z (and therefore to non-negative values of X, Y, and Z).
If one chooses any two points of color on the chromaticity diagram, then all the colors that lie in a straight line between the two points can be formed by mixing these two colors. It follows that the gamut of colors must be convex in shape. All colors that can be formed by mixing three sources are found inside the triangle formed by the source points on the chromaticity diagram (and so on for multiple sources).
An equal mixture of two equally bright colors will not generally lie on the midpoint of that line segment. In more general terms, a distance on the xy chromaticity diagram does not correspond to the degree of difference between two colors. In the early 1940s, David MacAdam studied the nature of visual sensitivity to color differences, and summarized his results in the concept of a MacAdam ellipse. Based on the work of MacAdam, the CIE 1960, CIE 1964, and CIE 1976 color spaces were developed, with the goal of achieving perceptual uniformity (have an equal distance in the color space correspond to equal differences in color). Although they were a distinct improvement over the CIE 1931 system, they were not completely free of distortion.
It can be seen that, given three real sources, these sources cannot cover the gamut of human vision. Geometrically stated, there are no three points within the gamut that form a triangle that includes the entire gamut; or more simply, the gamut of human vision is not a triangle.
Light with a flat power spectrum in terms of wavelength (equal power in every 1 nm interval) corresponds to the point (x,y) = (1/3,1/3).
Color Rendering Index
The color rendering index (CRI) (sometimes called color rendition index), is a quantitative measure of the ability of a light source to reproduce the colors of various objects faithfully in comparison with an ideal or natural light source. Light sources with a high CRI are desirable in color-critical applications such as photography and cinematography. It is defined by the International Commission on Illumination as follows:
Color rendering: Effect of an illuminant on the color appearance of objects by conscious or subconscious comparison with their color appearance under a reference illuminant.
The CRI of a light source does not indicate the apparent color of the light source; that information is under the rubric of the correlated color temperature (CCT).
CRI’s ability to predict color appearance has been criticized in favor of measures based on color appearance models, such as CIECAM02 and, for daylight simulators, the CIE Metamerism Index. CRI is not a good indicator for use in visual assessment, especially for sources below 5000 kelvins (K).
A newer version of the CRI, R96a, has been developed, but it has not replaced the better-known Ra general color rendering index
Colour Rendering Index (CRI) or Ra scale measures the ability of the light source to produce faithfully the colours of various objects in comparison with the natural light source. Natural outdoor light has a CRI of 100.
Based on CIE international standards, the Australian Standards group the Colour Rendering Index for lamps as shown below:
|1A||90 – 100||Excellent||Galleries, medical examinations, colour mixing|
|1B||80 – 89||Very good||Home, hotels, offices, schools|
|2A||70 – 79||Good||Industry, offices, schools|
|2B||60 – 69||Fairly good||Industry, offices, schools|
|3||40 – 59||Acceptable||Industry, sports halls|
|4||20 – 39||Poor||Traffic lighting|
|A beam similar to that of a torch is emitted by reflector lamps. This beam is usually shown accompanied by a ‘beam angle’ in degrees. This is a guide as to how light from the beam is concentrated or spread out.
Some lamp types are manufactured with a variety of beam angles. Lighting designers take advantage of this to tailor lighting schemes.
The beam angle is decided first by knowing the value of ‘peak intensity’. Peak intensity is quoted in candelas and measured in front of the lamp on an imaginary line called the axis, which usually runs directly through the centre of the lamp.
To one side of the axis the luminous intensity gradully diminishes. The line at which the intensity has diminished to half is called the line of haft peak intensity. The line of haft peak intensity is also measured for the other side. The angle between the two lines of haft peak intensity is the beam angle.
The IP Code (or Ingress Protection Rating, sometimes also interpreted as International Protection Rating) consists of the letters IP followed by two digits or one digit and one letter and an optional letter. As defined in international standard IEC 60529, IP Code classifies and rates the degrees of protection provided against the intrusion of solid objects (including body parts like hands and fingers), dust, accidental contact, and water in mechanical casings and with electrical enclosures.
The standard aims to provide users more detailed information than vague marketing terms such as waterproof. However, no edition of the standard is openly published for unlicensed readers.
The digits (characteristic numerals) indicate conformity with the conditions summarized in the tables below. Where there is no protection rating with regard to one of the criteria, the digit is replaced with the letter X.
For example, an electrical socket rated IP22 is protected against insertion of fingers and will not be damaged or become unsafe during a specified test in which it is exposed to vertically or nearly vertically dripping water. IP22 or 2X are typical minimum requirements for the design of electrical accessories for indoor use.
|IP Indication||Solid Particle Protection||Liquid Ingress Protection||Mechanical impact resistance||Other Protections|
|IP||Single Number: 0-6||Single Number: 0-8||Single Number: 0-9||Single Letter|
|Mandatory||Mandatory||Mandatory||No longer used||Optional|
WHAT IS LED LIGHTING AND WHY SHOULD
YOU CONSIDER Using LED’s (Light Emitting Diodes)
In our modern world of technology and competitiveness businesses and the general community. Are becoming more aware of operational cost, power consumption, and health issues for staff and now carbon emissions. We can help you with a large percentage of these costs and other benefits such as a healthy Environment to work in.
LED (Light Emitting Diode) is the way of the future and is now being used over a wide range of applications. Aviation lighting, automotive lights, Traffic signals, signs, Video displays, Commercial lighting and mining to name a few.
In today’s economical scene, business and the community are sceptical in spending a dollar. Unless the benefits and savings are clearly explained changing to LED is simply the right choice not only in terms of power savings but also helping our well being and the environment for now and the future.
Businesses have a view that converting to an LED lighting systems is expensive and complicated to incorporate into their existing lighting systems. WRONG: in fact most of our LED lights may be retro fitted into your existing futures.
Dollars saving in your lighting power costs, maintenance, and Replacement costs, superior lighting, less fatigue and improve healthy work environment.
With modern technology LED light supply a very high level of brightness and constant cover as compared to conventional lights.
One of the big advantages of LED lighting is the high luminous efficiency. Compare to a conventional incandescent globe of say 60 to 100watts emits about 15 lm / w and a standard 150 lm/w.
By switching over to LED lighting you will save up to 80% on your lighting electricity costs and these expenses will continue to rise!
Did you also know that fluoro globes fade in light output over time; the actual lumens become a fraction of the original specifications. Then you have the flicker, UV, hazardous mercury, fire hazard and extra power consumption running the ballast unit in the fluoro and soon the restricted used of these fluoro tubes.
The Savings add up and so does the return on your investment to LED lighting
LED lights present many advantages over incandescent lights.
Lower electricity consumption: Draws only a fraction of the power for equal light.
Improved robustness: Due to solid state design limited wear factor unlike conventional lighting.
Saving on replacement costs: Due to solid state design and longer usage life
Faster switching: On warm up just instant light
No heat emitted: Ideal for us in air-conditioned areas
Light efficiently: A 3watt LED globe replaces a 20watt conventional globe
Uniform lighting: Gives a better constant spread
LED lights: Have a usable life of up to 50,000. 50 times more than a halogen globe.
LED lights: Will save up to 80% plus on your lighting power costs.
LED lights: Require far less maintenance saving dollars in labour costs.
LED lights: Are cool to touch and eliminate burning if touched like conventional globes and tubes.
LED lights: Produce far less heat than conventional or halogen lights and provide a heaving saving on air-conditioning costs
LED lights: Produce more light per watt than incandescent globes and globes.
How can we help you?
We can conduct a survey of your Premises and property for lighting needs and identify what is required and show you the savings by switching to LED lighting.
LEDLites PTY LTD is a privately owned Australian family business.
Our LEDs lighting are marked by a C-Tick number N29928 which is the required compliance and approved registration in Australia.