LEDs cannot be manufactured with consistent optical properties as a result of the production processes involved. Brightness and color can vary substantially from component to component even in the same production batch. This is why LEDs have to be tested during production and in their final application. Comprehensive optical characterization is also essential during research and development of LEDs and for LED-based products.
Delta OHM has developed a unique solutions for determining luminous intensity, luminous flux, color, CRI, Color Temperature, Spectrum of LEDs.
The measurement systems generate very accurate results with reliable reproducibility in conformity with the guidelines of the CIE 127 document of the International Commission on Illumination. DeltaOHM manufacture the HD30.1 high-performance spectroradiometer to deliver these solutions.
Three areas of application are defined for our LED measurement products:
Laboratory applications: In research and development and in quality control;
Production testing: Wafer testing and die sorting in front-end, and testing and sorting of packaged LEDs in back-end;
Purchasing: especially regarding LED coming from China;
Since the development of high-brightness blue and white LEDs, the market for LED light has been booming. LEDs are used in displays, illuminated advertisements and lamps. The new light of white LEDs is already being integrated in cars, aircraft, traffic lights and classic architectural lighting. It's no surprise that a brilliant future has been predicted for LEDs. In the same time there are not easy or portable solution to evaluate these light source, usually random tested by a laboratory.
Companies like Osram, Philips and General Electric heavily work to improve LED light. DeltaOHM is cooperating intensively with LED integrator and user performing metrology analysis in his accredited laboratories. This commitment represents an investment in the future because joining forces in this way provides information on the needs of industry when it comes to measuring LEDs so this is why DELTA OHM was introducing you the new portable all-in-one SpectroRadiometer HD30.1.
The HD30.1 is manufactured by Delta Ohm for the spectral analysis of light in the visible range and ultraviolet. The instrument has been designed by combining maximum flexibility, cost reduction and ease of use.
The sensor coded HD30.S1 analyzes the visible spectral range (380nm-780nm) and calculates the following photo-colorimetric quantities:
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. These are measured in lux (lx)
Correlated Color Temperature CCT [K],
The color 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. Color 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 colors (bluish white), while lower color temperatures (2,700–3,000 K) are called warm colors (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 blueish white) for higher temperatures.
Trichromatic Coordinates [x,y] (CIE 1931) or [u',v'](CIE1978),
The CIE 1931 color spaces are the first defined quantitative links between physical pure colors (i.e wavelengths) in the electromagnetic Visible spectrum and physiological perceived colors in human Color Vision. The mathematical relationships that define these color spaces are essential tools for color management. They allow one to translate different physical responses to visible radiation in color inks, illuminated displays, and recording devices such as digital cameras into a universal human color vision response.
CRI (color rendering index, R1…R14, Ra),
The CIE color rendering index (CRI) is a method to determine how well a light source's illumination of eight sample patches compares to the illumination provided by a reference source. Cited together, the CRI and CCT give a numerical estimate of what reference (ideal) light source best approximates a particular artificial light, and what the difference is.
Photosynthetically Active Radiation, often abbreviated PAR, designates the spectral range (wave band) of solar radiation from 400 to 700 nanometers that photosynthetic organisms are able to use in the process of photosynthesis. This spectral region corresponds more or less with the range of light visible to the human eye. Photons at shorter wavelengths tend to be so energetic that they can be damaging to cells and tissues, but are mostly filtered out by the ozone layer in the stratosphere. Photons at longer wavelengths do not carry enough energy to allow photosynthesis to take place.
The sensor coded HD30.S2 analyzes the ultraviolet spectral band (220 nm-400 nm) and calculates the following radiometric quantities:
UVA irradiance (W / m2),
UVB irradiance (W / m2)
UVC irradiation (W / m2)
Ultraviolet (UV) light is electromagnetic radiation with a wavelength from 400 nm to 10 nm, shorter than that of visible light but longer than X-rays. The ultraviolet light is used in the most various industrial and civil sectors. Quite often it is not enough to know the total emission of the source, but it is crucial to know how this light is distributed in the spectrum.