Mounted LED Features

• Wavelengths Ranging from 265 nm to 5200 nm (See LED Quick Links Table to the Right)
• White, Broadband, and Dual-Peak LEDs Also Available
• Integrated Memory Stores LED Operating Parameters
• Thermal Properties Optimized for Stable Output Power
• Microscope- and SM-Thread-Compatible Collimation Adapters Available
• 4-Pin Female Mating Connector for Custom Power Supplies can be Purchased Separately

Each Thorlabs uncollimated, mounted LED consists of a single LED mounted to the end of a heat sink with 6 mm deep, SM1 (1.035"-40) internal threads. LEDs with Ø1.20" heat sinks have the same outer diameter as an SM1 Lens Tube, allowing them to fit inside a 30 mm Cage System. A selection of our LEDs are mounted to larger heat sinks, as they generate more heat during operation. These heat sinks are enclosed in Ø57.0 mm vented plastic housings and include four 4-40 tapped holes on the front for integration with 30 mm cage systems.

Every LED features an EEPROM chip which stores information about the LED (e.g., current limit, wavelength, forward voltage). When controlled by a Thorlabs LED driver designed to read the EEPROM chip, the data can be used to implement smart safety features. 

These mounted LEDs possess good thermal stability properties, eliminating the issue of degradation of optical output power due to increased LED temperature. For more details, please see the Stability tab.

Please note that mounted LEDs are not intended for use in household illumination applications.

LED Collimation
Our adjustable collimation adapters can translate a Ø1" (Ø25 mm) or Ø2" (Ø50 mm) lens by up to 11 mm or 20 mm, respectively. Each adjustable collimation adapter includes an internal SM2 (2.035"-40) thread adapter so that the LEDs can be easily integrated with Thorlabs' SM2-threaded components, such as our Ø2" lens tubes. These adapters are offered in versions with and without an AR-coated aspheric condenser lens.

In addition, microscope collimation adapters are available that incorporate an AR-coated aspheric lens. These adapters mate to the epi-illumination ports on select Leica DMI, Nikon Eclipse Ti, Olympus IX/BX, or Zeiss Axioskop microscopes. Thorlabs also offers mounted LEDs with pre-attached microscope collimation adapters.

We offer suggestions for collimating most LEDs. Click on the info icon () for each LED below for details. The Collimation tab provides additional information on collimating an LED.

Driver Options
Thorlabs offers six drivers compatible with some or all of these LEDs: LEDD1B, UPLED, DC40, DC2200, DC4100, and DC4104 (the latter two require the DC4100-HUB). See the tables below for driver compatibility information, and the LED Drivers tab for a list of specifications. The UPLED, DC40, DC2200, DC4100, and DC4104 drivers are capable of reading the current limit from the EEPROM chip of the connected LED and automatically adjusting the maximum current setting to protect the LED.

Multi-LED Source
A customizable multi-LED source may be constructed using our mounted LEDs and other Thorlabs items. This source may be configured for integration with Thorlabs' versatile SM1 Lens Tube Systems and 30 mm Cage Systems. Please see the Multi-LED Source tab for a detailed item list and instructions.

Thorlabs also offers integrated, user-configurable 4-Wavelength High-Power LED Sources.

Relative Power

The actual spectral output and total output power of any given LED will vary due to variations in the manufacturing process and operating parameters, such as temperature and current. Both a typical and minimum output power are specified to help you select an LED that suits your needs. Each mounted LED will provide at least the minimum specified output power at the maximum current. In order to provide a point of comparison for the relative powers of LEDs with different nominal wavelengths, the spectra in the plots below have been scaled to the minimum output power for each LED. This data is representative, not absolute. Excel files with normalized and scaled spectra for each set of the mounted LEDs can be downloaded by clicking below the graphs.

LED Lifetime and Long-Term Power Stability

One characteristic of LEDs is that they naturally exhibit power degradation with time. Often this power degradation is slow, but there are also instances where large, rapid drops in power, or even complete LED failure, occur. LED lifetimes are defined as the time it takes a specified percentage of a type of LED to fall below some power level. The parameters for the lifetime measurement can be written using the notation B_XX/L_YY, where XX is the percentage of that type of LED that will provide less than YY percent of the specified output power after the lifetime has elapsed. Thorlabs defines the lifetime of our LEDs as B₅₀/L₅₀, meaning that 50% of the LEDs with a given item # will fall below 50% of the initial optical power at the end of the specified lifetime. For example, if a batch of 100 LEDs is rated for 150 mW of output power, 50 of these LEDs can be expected to produce an output power of ≤75 mW after the specified LED lifetime has elapsed.

The sample plot to the right shows example data from long-term stability testing over a 45 day period for a 340 nm mounted LED, which had a lifetime of >3,000 hours (~125 days). The small power drop experienced by the LED after it is turned on is typical behavior during the first few minutes of operation. It corresponds to the period of time required for the LED to warm up to the point where it is thermally stable. Please note that this graph represents the performance of a single LED; the performance of individual LEDs will vary within the stated specifications.

Optimized Thermal Management

The thermal dissipation performance of these mounted LEDs has been optimized for stable power output. The heat sink is directly mounted to the LED mount so as to provide optimal thermal contact. By doing so, the degradation of optical output power that can be attributed to increased LED junction temperature is minimized (see the graph to the left).

Video Insight: Collimate Light from an LED

Collimating light from an LED or other large, incoherent source can be a surprisingly challenging task. The emitter’s size and the collimating lens’ focal length and numerical aperture (NA) all influence the characteristics of the collimated beam. It can also be hard to know when the lens is positioned optimally. In this video, two collimation approaches are demonstrated. In addition, two lenses with different NAs and focal lengths are used to show that a benefit of increasing the lens’ NA is collecting more power from the LED, but that a higher NA comes at a cost of increasing the rate at which the collimated beam diverges.

Two Collimation Methods for LEDs

As demonstraded in the Video Insight above, the distance between the selected collimating optic and the LED may need to be adjusted to ensure that the LED is suitably collimated. Collimation can only be achieved over a local region of the beam path. In this collimated region the beam has minimal divergence and will not converge at any point (see images below for comparison). As with any beam, perfect collimation is not achievable; any collimated beam diverges at some rate. For incoherent sources like LEDs, the rate of divergence is higher when the emitter size is larger. Two methods for achieving a collimated beam are outlined here.

Method 1: Form an Image of the LED at Infinity

1. Power on the LED.
2. Place a viewing screen ~1-2 feet away from the collimating optic.
3. Adjust the distance between the collimating optic and the LED to form an image of the LED on the viewing screen (Image A below).
4. Move the viewing screen farther away from the LED.
5. Repeat steps 3 and 4 as much as space allows.
6. Returning the viewing screen to ~1-2 feet away from the collimating optic should show a non-converging, homogenous beam. The beam should be somewhat circular, may have a slightly polygonal shape, and should not be a clear image of the LED itself. Image C shows an example of a collimated beam.
7. Once the optimal position of the collimating optic has been found, lock the position of the collimating optic in place.

Note: Space contraints may limit this approach's usefulness. When space is limited, method 2 (below) may be more advantageous.

Method 2: Use the Divergence of the Beam to Set the Collimating Optic Position

1. Determine the expected beam diameter (D₂) a distance L away from the output of the collimating optic:

Figure 1 shows the propagation of the beam emitted by the LED and passing through the collimating optic. The expected divergence angle of the beam (Φ_e) after the collimating optic is given by

where d is the lateral size of the LED, and f is the focal length of the lens or collimating optic. The expected beam diameter D₂ a distance L away from the collimating optic can be calculated using

where

Substituting equation 1 into equation 3 yields ΔD=Ld/f, so we have

2. Power on the LED.
3. Place a viewing screen at distance L away, and adjust the position of the collimating optic to set D₂ on the viewing screen.
4. This is the optimal position of the collimating optic; lock the position of the collimating optic in place.

The table below provides examples of how the half viewing angle changes for select LEDs with the addition of a Ø1" aspheric condenser lens (ACL2520U). See the Collimation Adapter tab in the info icons (  ) below for the recommended collimating optic for select LEDs. 

Item #	Color	Nominal Wavelengtha	Calculated Lens to Emitter Distanceb	Half Viewing Anglec
				+1 mm Out of Focusd	at Calculated Focusing Distance	-1 mm Out of Focusd
M850L3	IR	850 nm	13.8 mm	3.29°	3.10°	3.93°
M940L3	IR	940 nm	13.9 mm	3.42°	2.46°	3.70°

• The specifications listed in the table above are nominal values specified by the LED manufacturer.
• Calculated distance between the respective mounted LED and the ACL2520U lens used to collimate the beam.
• Power loss to 1/e² (13.5%). The divergence data was calculated using Zemax.
• ±1 mm out of focus from Calculated Distance between the respective mounted LED and the ACL2520U lens used to collimate the beam.

Pin Connection - Male

The diagram to the right shows the male connector of the mounted LED assembly. It is a standard M8 x 1 sensor circular connector. Pins 1 and 2 are the connection to the LED. Pin 3 and 4 are used for the internal EEPROM in these LEDs. If using an LED driver that was not purchased from Thorlabs, be careful that the appropriate connections are made to Pin 1 and Pin 2 and that you do not attempt to drive the LED through the EEPROM pins.

Creating a Custom Multi-LED Source for Microscope Illumination

Thorlabs offers the items necessary to create your own custom multi-LED light source using two or three of the mounted LEDs offered below. As configured in the following example, the light source is intended to be used with the illumination port of a microscope. However, it may be integrated with other applications using Thorlabs' versatile SM1 Lens Tube and 30 mm Cage Systems. Thorlabs also offers integrated, user-configurable 4-Wavelength LED Sources.

Design & Construction

First, light will be collimated by lenses mounted in lens tubes. Dichroic mirrors mounted in kinematic cage cubes then combine the output from the multiple LEDs. The mounted LEDs may be driven by LEDD1B Compact T-Cube LED Drivers (power supplies are sold separately). The LEDD1B LED Drivers allow each LED's output to be independently modulated and can provide up to 1200 mA of current. Please take care not to drive the LED sources above their max current ratings.

When designing your custom source, select mounted LEDs from below along with dichroic mirror(s) that have cutoff wavelength(s) between the LED wavelengths. The appropriate dichroic mirror(s) will reflect light from side-mounted LEDs and transmit light along the optical axis. Please note that most of these dichroic mirrors are "longpass" filters, meaning they transmit the longer wavelengths and reflect the shorter wavelengths. To superimpose light from three or more LEDs, add each in series (as shown below), starting from the back with longer wavelength LEDs when using longpass filters. Shortpass filters may also used if the longer wavelength is reflected and the shorter wavelength is transmitted. Sample combinations of compatible dichroic mirrors and LEDs are offered in the three tables below.

It is also necessary to select an aspheric condenser lens for each source with AR coatings appropriate for the source. Before assembling the light source, collimate the light from each mounted LED as detailed in the Collimation tab. For mounting the aspheric lenses in the SM1V05 Lens Tubes using the included SM1RR retaining rings, we recommend the SPW801 Adjustable Spanner Wrench. A properly collimated LED source should have a resultant beam that is approximately homogenous and not highly divergent at a distance of approximately 2 feet (60 cm). An example of a well-collimated beam is shown on the Collimation tab.

After each LED source is collimated, thread the SM1V05 Lens Tubes at the end of each collimated LED assembly into their respective C4W Cage Cube ports using SM1T2 Lens Tube Couplers. Install each dichroic filter in an FFM1 Dichroic Filter Holder, and mount each filter holder onto a B4C Kinematic Cage Cube Platform. Each platform is then installed in the C4W Cage Cubes by partially threading the included screws into the bottom of the cube, and then inserting and rotating the B4C platform into place. Align the platform to the desired position and then firmly tighten the screws. To connect multiple cage cubes and the microscope adapter, use the remaining SM1T2 lens tube couplers along with an SM1L05 0.5" Lens Tube between adjacent cage cubes. Finally, adjust the rotation, tip, and tilt of each B4C platform to align the reflected and transmitted beams so they overlap as closely as possible.

If desired, a multi-LED source may be constructed that employs more than three LEDs. The limiting factors for the number of LEDs that can be practically used are the collimation of the light and the dichroic mirror efficiency over the specified range. Heavier multi-LED sources may be supported with our Ø1" or Ø1.5" Posts.

Ray data for Zemax is available for some of the bare LEDs incorporated into these high-powered light sources. This data is provided in a zipped folder that can be downloaded by clicking on the red document icons () next to the part numbers in the pricing tables below. Every zipped folder contains an information file and one or more ray files for use with Zemax:

• Information File: This document contains a summary of the types of data files included in the zipped folder and some basic information about their use. It includes a table listing each document type and the corresponding filenames.
• Ray Files: These are binary files containing ray data for use with Zemax.

For the LEDs marked with an superscript "a" in the table to the right, the following additional pieces of information are also included in the zipped folder:

• Radiometric Color Spectrum: This .spc file is also intended for use with Zemax.
• CAD Files: A file indicating the geometry of the bare LED. For the dimensions of the high-power mounted LEDs that include the package, please see the support drawings provided by Thorlabs.
• Sample Zemax File: A sample file containing the recommended settings and placement of the ray files and bare LED CAD model when used with Zemax.

The table to the right summarizes the ray files available for each LED and any other supporting documentation provided.

Using Mounted LEDs in Cerna^® Microscope Systems

Mounted LEDs, which can have either narrowband or broadband spectra, are useful for a range of applications within Thorlabs' Cerna microscopy platform:

• Fluorescence Microscopy
• Brightfield Microscopy
• Near Infrared/Infrared (NIR/IR) Microscopy

If you are interested in using a mounted LED with a Cerna modular microscopy system, the mounted LED can be attached by way of the single-cube epi-illuminator module (Item # WFA2001), which contains AR-coated optics optimized for the 350 - 700 nm wavelength range. The mounted LED and epi-illuminator module are connected together by an externally threaded coupler (Item # SM1T10, provided with the WFA2001), which includes two knurled locking rings (Item # SM1NT, also provided with the WFA2001) that are tightened by hand. The mounted LED is then powered by a driver, sold separately. Please see the LED Drivers tab to identify the appropriate driver for your mounted LED. If you wish to connect multiple mounted LEDs to the epi-illuminator module, contact Technical Support.

Please see the Overview tab to choose the appropriate color spectrum of mounted LED for your imaging needs. Again, note that the epi-illuminator module is optimized for 350 - 700 nm wavelength illumination sources. 

Certain mounted LEDs are also compatible with our illumination kits for trans-illumination. Please contact Technical Support if you wish to use an LED not currently offered as a component of these kits, as the collimating optics are optimized for certain beam characteristics.

To fully support the max optical power of the LED you intend to drive, ensure that the max voltage and max current of the driver are equal to or greater than those of the LED. Drivers matching these conditions are listed in the Recommended Drivers columns of the LED tables below.

Compatible Drivers	LEDD1B	UPLEDa	DC40a	DC2200a	DC4100a,b	DC4104a,b
Click Photos to Enlarge
LED Driver Current Output (Max)c	1.2 A	1.2 A	4.0 Ad	LED1 Terminal: 10.0 A LED2 Terminal: 2.0 Ae	1.0 A per Channel	1.0 A per Channel
LED Driver Forward Voltage (Max)f	12 V	8 V	14.0 Vd	50 V	5 V	5 V
Modulation Frequency Using External Input (Max)	5 kHzg	-	5 kHzg	250 kHzg,h	100 kHzg (Simultaneous Across all Channels)	100 kHzg (Independently Controlled Channels)
External Control Interface(s)	Analog (BNC)	USB 2.0	USB 2.0, TTL, and Analog (BNC)	USB 2.0 and Analog (BNC)	USB 2.0 and Analog (BNC)	USB 2.0 and Analog (8-Pin)
Main Driver Features	Very Compact Footprint 60 mm x 73 mm x 104 mm (W x H x D)	USB-Controlled	Driver Current Up to 4.0 A, Manual and USB-Controlled	Touchscreen Interface with Internal and External Options for Pulsed and Modulated LED Operation	4 Channelsb	4 Channelsb
EEPROM Compatible: Reads Out LED Data for LED Settings	-
LCD Display	-	-	-

• Automatically limits to LED's max current via EEPROM readout.
• The DC4100 and DC4104 can power and control up to four LEDs simultaneously when used with the DC4100-HUB. The LEDs on this page all require the DC4100-HUB when used with the DC4100 or DC4104.
• LEDs with maximum current ratings higher than the driver's maximum current output can be driven, but will not reach full power. See the tables below for the maximum current rating and recommended drivers for each LED.
• The DC40 LED Driver is designed to automatically select the appropriate current/voltage combination for the LEDs on this page. Please note that the maximum current and forward voltage are interdependent; the DC40 driver cannot drive an LED with a 14.0 V forward voltage at 4.0 A. Please see the full web presentation for more information.
• The mounted LEDs sold below are compatible with the LED2 Terminal.
• LEDs with forward voltage greater than the driver's maximum forward voltage cannot be driven. See the tables below for the forward voltage specification and recommended drivers for each LED.
• Several of these LEDs produce light by stimulating emission from phosphor, which limits their modulation frequencies. The M565L3, M595L4, and all purple or white LEDs may not turn off completely when modulated above 10 kHz at duty cycles below 50%. The MBB1L3 LED may not turn off completely when modulated at frequencies above 1 kHz with a duty cycle of 50%. When the MBB1L3 is modulated at frequencies above 1 kHz, the duty cycle may be reduced; for example, 10 kHz modulation is attainable with a duty cycle of 5%.
• Small Signal Bandwidth: Modulation not exceeding 20% of full scale current. The driver accepts other waveforms, but the maximum frequency will be reduced.

This tab includes all LEDs sold by Thorlabs. Click on More [+] to view all available wavelengths for each type of LED pictured below.