Products, Materials + Tools | Nov 13, 2006

Future Lighting Solutions launches Usable Light Tool

Often, when evaluating high-power LEDs, typical flux values, which are measured at a junction temperature of 25°C, are considered only. Such an analysis is incomplete and inaccurate for determining the expected level of light from the light source in a "real world" environment.

The purpose of this tool is to provide a true "real world" evaluation and comparison of high-power LEDs by taking into account the effects of 7 critical relationships (see diagram):

Working principals of the Usable Light Tool

While respecting the maximum Junction Temperature specified, the Usable Light Tool optimizes the Drive Current to maximize the light output of the selected LED. The models created for each LED are based on values obtained directly from the LED manufacturer's datasheets.  The tool incorporates 3 major sources of data as well as a variety of secondary data points, which are explained below.

Data Source 1:  As seen in the graph below the Light Output increases as the Drive Current does.

However, as the drive current increases, so does the power consumption, and the greater the power consumption, the more heat is generated.

Data Source 2:  As seen in the graph below, as the Drive Current increases, the Forward Voltage increases.

Since power consumption is the product of current and voltage, the rise of Forward voltage also increases the power consumption, which generates additional heat.

Data Source 3:  Finally, as seen in the graph below, the Light Output decreases as the Junction Temperature increases.

The Usable Light Tool also incorporates the following data points for running it's proprietary current optimizing algorithm:

  • Ambient Temperature

  • Heat Sink Thermal Resistance

  • Power LED Junction to Case Thermal Resistance

  • Effects of Junction Temperature on Forward Voltage

  • Recommended Junction Temperature

  • Number of LEDs

  • Maximum allowable Drive Current

  • Power LED Flux Bin

  • Power LED Forward Voltage Bin

As was stated above, the Usable Light tool calculates the drive current that will maximize the usable flux that will not exceed the advised maximum junction temperature.  However, the optimal current also maximizes the luminous efficacy for the calculated maximum usable flux.  Therefore, the optimal current may not always be the maximum current.

See Future Lighting Solutions in our buyer's guide.

Add comment

You can add a comment by filling out the form below. Plain text formatting. Comments are moderated.

Question: What is 1 + 4 ?
Your answer:
FEATURED

LumiTop 4000: Comprehensive Optical Wafer Testing for μLEDs

LumiTop 4000: Comprehensive Optical Wafer Testing for μLEDs Instrument Systems offers a unique camera-based measurement solution for μLED wafer testing that generates 2-dimensional, pixel-resolved optical analyses within given cycle times. The LumiTop 4000 has a resolution of 12 MP and can detect the smallest of defects and inhomogeneities on the wafer. ... Read more »

FEATURED

Lumileds Maximizes Field Usable Lumens: New LUXEON HL2X LED

Lumileds Maximizes Field Usable Lumens: New LUXEON HL2X LED Lumileds introduces the LUXEON HL2X, the ideal choice for roadway lighting and sports lighting fixtures with the highest flux and efficiency in an industry standard package. "With 318+ lumens at 700 mA and 85°C, LUXEON HL2X delivers more 'field usable lumens' for optical engineers to work with. ... Read more »

EDITORIAL

Australian Associated Press Recently Wrote: Red Light Could Improve Over-40s' Eyesight

Australian Associated Press Recently Wrote: Red Light Could Improve Over-40s' Eyesight A small LED torch that emits deep red light could help improve declining eyesight, scientists have said: A study by University College London, involving a small sample size of 24 people, has shown that staring at long wavelength light for three minutes every day can "significantly improve vision" ... Read more »

EDITORIAL

Signify Invests to Broaden Its UV-C Lighting Portfolio for Professional Disinfection

Signify Invests to Broaden Its UV-C Lighting Portfolio for Professional Disinfection Signify, the world leader in lighting, is increasing its UV-C lighting production capacity and expanding its UV-C product portfolio. The company is leveraging more than 35 years of expertise in UV-C lighting to address the growing global need for the disinfection of air, surfaces and objects. Read more »