Frequently Asked Questions (FAQ) About Luxeon LEDs
If you can't find an answer to your question here, please contact us here. We will do our best to respond within one business day.
Our current "Top Ten" Questions (Updated Jan 6, 2008)
- When will lenses be available for the Rebel Star LEDs?
- When will K2 or Rebel TFFC LEDs start shipping?
- Can I get a Rebel Star in a color other than white or RGB?
- Can I get a K2 Star in a color other than white, red, blue or green?
- Do you have 1500mA drivers for the K2 LEDs?
- Are Luxeon LEDs available in UV?
- Are Luxeon LEDs available in IR?
- Can I buy just the K2 or Rebel Star base?
- When will you have the new K2 with TFFC?
- What is the brightest white LED available?
Technical Questions
Questions About Ordering
Glossary
When will lenses be available for the Rebel Star LEDs?
The manufacturer hopes to release a tri-lens for the Rebel Star LEDs in 2008.
When will K2 or Rebel TFFC LEDs start shipping?
The last update we received from our supplier is that we will start to receive inventory for the K2 and Rebel TFFC LEDs in late May or early June, however this is just a projection and is not guaranteed.
Can I get a Rebel Star in a color other than white or RGB?
Not yet. We hope to expand our line of color Rebel Stars in 2008.
Can I get a K2 Star in a color other than white, red, blue or green?
Not yet. We hope to expand our line of color K2 Stars in 2008.
Do you have 1500mA drivers for the K2 LEDs?
At the present time there are no off-the-shelf 1500mA drivers available for the K2 LEDs We are actively looking for a supplier and hope to have something available in 2008. In the meantime if you want to power the K2 (or other Luxeon LEDs that are rated to operate at currents higher than 1000mA), you will need to design your own driver. A very simple (but not very efficient) driver can be built using an LM317 voltage regulator configured as a constant current regulator. You will find a sample circuit here.
Are Luxeon LEDs available in UV?
Luxeons are not available in wavelengths below 455nm (Royal Blue). The manufacturer has not announced any plans to produce UV LEDs.
Are Luxeon LEDs available in IR?
Luxeons are not available in wavelengths above 625nm (Red). The manufacturer has not announced any plans to produce IR LEDs.
Can I buy just the K2 or Rebel Star base?
We plan on releasing a line of Rebel and K2 Star bases in early 2008. Watch our website for announcements.
When will you have the new K2 with TFFC?
The K2 with TFFC is available to order now from here.
What is the brightest white LED available?
The brightest single LED that we currently offer is the Rebel XML-PWN1-0080, which is rated at 145 lumens. The soon to be released K2 TFFC will surpass that with lumen outputs that can exceed 200 lumens The brightest LED assembly that we offer is the 7007-PWC-10-3 Rebel Star tri-LED which has an output rating of 540 lumens with the same footprint and size as a standard Luxeon Star LED.
Do you provide free samples?
Unfortunately we are unable to supply evaluation samples of our products. We can however accept orders for single piece quantities from our website.
How do I power Luxeon LEDs?
Luxeon (and other LEDs) are current driven devices and must have input current carefully regulated. For testing and experimentation a simple DC voltage source with current limiting resistor will work quite well. However, while you can power Luxeon LEDs using just a current limiting resistor, it is highly recommended that a commercial driver or Pulse Width Modulation circuit be used for anything more than just bench testing.
More details about powering Luxeon LEDs can be found in the manufacturers application brief "Electrical Drive Information".
Can Luxeon LEDs be dimmed?
Yes, dimming can be achieved using Pulse Width Modulation (PWM). The dynamic range the LED exceeds 1,000:1.
How do I convert lumens to candelas and vice-versa?
Lumens and candelas measure very different effects and it really is not possible to convert from one to the other. Lumens measures how much light is produced as measured at the light source. Candelas measure how much light actually falls on a surface.
If you want to compare the performance of traditional LEDs to Luxeons for your application, we recommend that you simply try the Luxeon LEDs.
What are the max and min switching frequencies for Luxeon?
The maximum and minimum switching frequencies for Luxeon are determined by your drive current. If you are not exceeding the Maximum DC Forward Current, then t here is no minimum frequency. The Luxeon response time is the only restriction for the maximum frequency. If you are not exceeding either the Maximum Peak Pulsed Forward Current nor the Maximum Average Forward Current, then the Maximum Duty Factor of the pulse that is driving the LEDs is limited to 70% for Green/Cyan/Blue/White LEDs and to 65% for Red/Red-Orange/Amber LEDs.
The minimum frequency on all Luxeon is limited to 1 kHz at the maximum duty cycles described above. Since at lower frequencies the peak junction temperature is higher than the average max junction temperature, light output and lifetime of the device can be sacrificed. The maximum frequency is only limited by the response time. For more information about how to pulse-drive LEDs please read the application brief, "Custom Luxeon Design Guide". Be sure to check the table for Electrical Maximum Ratings for Pulsed Operation.
What is the Luxeon's typical response time?
Less than 100ns. (1ns is equal to 1billionth of a second.)
Are Luxeon light sources weatherproof?
It depends on the applications design, engineering parameters and manufacturing processes that you are using. A thorough set of environmental tests have been performed on Luxeon Emitters and can be found in the application brief, "Custom Luxeon Design Guide".
Where can I get information about Luxeon's reliability?
Lumileds has done extensive reliability testing on the Luxeon light sources. Detailed information can be found in the application brief, "Custom Luxeon Design Guide".
Are the Relative Spectral Power Distribution Graphs Radiometric or Photometric?
They are all Radiometric.
Should I use a tape or adhesive to aid in thermal contact?
Whenever possible, we recommend that you mount Luxeon LEDs directly to a heat sink using mechanical fasteners. Tapes and adhesives can aid in thermal contact with uneven surfaces but they also add thermal resistance.
Keep in mind that unless otherwise noted, the base of Luxeon emitters and stars is not electrically neutral and that you must be sure to isolate the base from the heat sink.
I'm not a technician or engineer. Is there a simple way for me to light my Luxeon?
The simplest option is to use a pre-built LED driver. The PowerPuck drivers are the easiest to use. Just connect the input to a DC voltage source and the output to the LED and you are business. The BuckPuck drivers offer more flexibility such as output on/off and dimming control.
What is the difference between a standard Luxeon Star and a Luxeon/O?
The Luxeon/O is a single emitter mounted on a square aluminum core PC board with a lens (Luxeon collimator) that will focus the light output to 10°.
What is the difference between a standard Luxeon Star and a Luxeon/C?
The Luxeon/C is a single emitter mounted on a square aluminum core PC board and includes an AMP connector.
What is the difference between a standard Luxeon Star and a Luxeon/IDC?
The Luxeon/IDC is a single emitter mounted on a square aluminum core PC board that is equipped with Zierick Insulation Displacement Connectors.
How do I order Luxeon LEDs?
You can order Luxeon LEDs right here.
What does it cost to ship?
To determine the cost of shipping, add the parts that you want to order to the cart and then click on the Calculate Shipping Costs button. This will provide you with a list of all the shipping option we offer, their ship times and costs.
Can you provided "Binned" LEDs?
No. As an online retailer specializing in servicing experimenters and small production runs, we are unable to supply binned product. Minimum order quantities for each bin number are very high. (1k+ to 10K+) We are unable to pre-select binned LEDs from our existing inventory.
Thin Film Flip Chip (TFFC)
Thin Film Flip Chip is a manufacturing process that provides significant improvement to lumen and output power for Luxeon LEDs.
Pulse Width Modulation (PWM)
Pulse Width Modulation is a constant stream of pulses of a fixed frequency, fixed amplitude and variable duration that can be used to control the current to an LED, effectively controlling the light output. The duty cycle of the pulse can fall within the following range: 0%< duty cycle <100%.
Lumens
Lumens measures how much light is produced as measured at the light source.
Batwing
Batwing Luxeons (sometimes called 'low dome' LEDs) have a clear resin dome with a nearly flat top surface. Batwings project a flatter, forward distributed light designed to evenly fill an illuminated surface.
Side Emitting
Just like the name suggest, side emitting LEDs project most of the generated light sideways. This produces a toroid of light that is useful for lighting large opaque surface areas. Side emitting LEDs are commonly used in flashlights with a reflector that directs the light forward.
Lambertian
Lambertian LEDs (sometimes called 'high dome' LEDs) have a high hemispherical dome that project a wider beam pattern of 140 degrees without any loss of light intensity. They produce an even distribution of light in all directions.
|
