Cage-Compatible Diffuse Backlight LED

  • LED Backlight with Ø25 mm Diffused Aperture Size
  • Integrates with 30 mm Cage Systems
  • Compatible with Thorlabs' LED Drivers

Application Idea

The LEDD1B T-Cube LED Driver can be used to drive the LEDBW1 Backlight LED. 


Ø25 mm Diffuse Backlight LED, Cold White

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Item # LEDBW1
Min Typical Max
LED Power Outputa,b 251 mW 358 mW -
Forward Voltagea,b - 3.9 V -
Maximum Irradiancea,b,c - 6.3 µW/mm2 -
General Specifications
Color Cold White
Correlated Color Temperatured 6500 K
Diffused Aperture Sizee Ø25 mm
Maximum Current (CW)a 2000 mA
Electrical Powera 7800 mW
Typical Lifetimea 100 000 h
Operating Temperaturef 0 to 40 °C
Storage Temperature -40 to 70 °C
Risk Groupg RG0 - Exempt
Output Spectrumd
(Click to View)

Click Here for Raw Data
  • Measured at 25 °C
  • When Driven with the Maximum Current
  • Measured at a Distance of 200 mm
  • Due to variations in the manufacturing process and operating parameters such as temperature and current, the actual spectral output of any given LED will vary. Correlated color temperature specs are only intended to be used as a guideline.
  • To discuss alternative diffused aperture sizes, please contact Tech Support.
  • Non-Condensing
  • According to the Standard IEC 62471:2006, Photobiological Safety of Lamps and Lamp Systems
LEDBW1 Bottom Light LED with LEDD1B Driver and CFS1M Filter Mount
Click to Enlarge
The CFS1(/M) Sliding Filter Mount can be used with the LEDBW1 Cage-Compatible LED Backlight to filter specific wavelength ranges of the output.


  • High-Power Diffuse Illuminator Ideal for Machine Vision Applications
  • Ø25 mm Diffused Aperture Size
  • 100 000 Hour Lifetime
  • Compatible with Our 30 mm Cage System  
  • Low-Profile Housing
  • Integrated Memory (EEPROM) Stores LED Operating Parameters
  • Integrated M8 Connector for use with Thorlabs' LED Drivers

Thorlabs' Cage-Compatible Diffuse Backlight LED is a high-power, cold white LED that provides stable, uniform illumination. By integrating a Ø25 mm diffused window, this LED backlight produces a flatter field of illumination as compared to a point source, making it ideal for machine vision applications.

Constructed from anodized aluminum, this LED housing features four through holes that are compatible with our Ø6 mm ER cage rods. This allows for integration with our 30 mm cage systems and DIY Cerna components, such as the CSA1001 Fixed Arm. Each cage rod through hole is accompanied by two side-located locking setscrews, which can be secured using a 5/64" (2.0 mm) hex key or balldriver.

To ensure proper operation and to maximize operating lifetime, this LED backlight must be mounted onto an appropriate heat sink; the housing includes four counterbored slots that accept 1/4" (M6) cap screws (not included) for compatibility with both imperial and metric hole patterns. For convenient connection to the drivers listed on the LED Drivers tab, this LED backlight has a connection cable with an M8 connector; see the Pin Diagrams tab for the M8 connector pin information.

This LED backlight features an EEPROM chip which stores information about the LED (e.g., current limit, forward voltage). When controlled by a Thorlabs DC2200, DC4100, DC4104, or UPLED LED driver, the data can be used to implement smart safety features.

White Light LEDs
This illuminator is a cold white LED featuring a broad spectrum that spans several hundred nanometers; see the table to the right for a typical output spectrum. It has a correlated color temperature of 6500 K, which indicates that the color appearance is similar to a black body radiator at the same temperature. In general, a cold white LED has a stronger blue component to the spectrum than a warm white or neutral white LED. Compared to warm white LEDs, cold white LEDs are more suitable for fluorescence microscopy applications or use with cameras with white balancing due to their higher intensity at most wavelengths. To discuss LED backlights with other correlated color temperatures or nominal wavelengths, please contact Tech Support.

Driver Options
Thorlabs offers five drivers compatible with this LED backlight: DC2200, UPLED, LEDD1B, DC4100, and DC4104 (the latter two require the DC4100-HUB). See the LED Drivers tab for compatibility information and a list of specifications. We recommend using the DC2200 for applications that require the full power of the LED; the LEDBW1 LED has a higher maximum current rating than the the UPLED, LEDD1B, DC4100 and DC4101 drivers are able to provide, which will limit the achievable LED output power when used with these drivers. In addition, the DC2200, DC4100, DC4104, and UPLED 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.

Please note that this LED backlight is not intended for use in household illumination applications.

Thorlabs also offers a range of unmounted, mounted, collimated, and fiber-coupled LEDs that are designed for a variety of applications, including microscopy, illumination, and measurements. For questions on choosing an appropriate LED and to discuss mounting requirements, please contact Tech Support.

Pin Out
Pin Specification Color
1 LED Anode Brown
2 LED Cathode White

Pin Connection - Male

The diagram to the right shows the male connector of the LEDBW1 Backlight. 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. 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.

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.

Compatible Drivers LEDD1B UPLEDa DC2200a DC4100a,b DC4104a,b
Click Photos to Enlarge LEDD1B Driver upLED Driver DC2200 Driver DC4100 Driver DC4104 Driver
LED Driver Current Output (Max)c 1.2 A 1.2 A LED1 Terminal: 10.0 A
LED2 Terminal: 2.0 Ad
1.0 A per Channel 1.0 A per Channel
LED Driver Forward Voltage (Max)e 12 V 8 V 50 V 5 V 5 V
Modulation Frequency Using External Input (Max) 5 kHz - 250 kHzf,g 100 kHzg
(Simultaneous Across all Channels)
100 kHzg
(Independently Controlled Channels)
External Control Interface(s) Analog (BNC) USB 2.0 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 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 - Yes Yes Yes Yes
LCD Display - - Yes Yes Yes
  • Automatically Adjusts the Driver's Current Limit via EEPROM Readout from LED
  • The DC4100 and DC4104 can power and control up to four LEDs simultaneously when used with the DC4100-HUB. The LEDBW1 requires the DC4100-HUB when used with the DC4104 driver.
  • LEDs with maximum current ratings higher than the driver's maximum current output can be driven, but will not reach full power.
  • The LED sold below is compatible with the LED2 Terminal.
  • LEDs with forward voltage greater than the driver's maximum forward voltage cannot be driven. All drivers in this table are capable of driving the LEDBW1.
  • Small Signal Bandwidth: Modulation not exceeding 20% of full scale current. The driver accepts other waveforms, but the maximum frequency will be reduced.
  • The LEDBW1 produces light by stimulating emission from phosphor, which limits the modulation frequency. As a white LED, the LEDBW1 may not turn off completely when modulated above 10 kHz at duty cycles below 50%.

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

Light Emitting Diode (LED) Selection Guide
Click Photo to Enlarge
(Representative; Not to Scale)
Type Unmounted LEDs Pigtailed LEDs LEDs in
SMT Packages
LED Arrays LED Ring Light Cage-Compatible
Diffuse Backlight LED
Light Emitting Diode (LED) Selection Guide
Click Photo to Enlarge
(Representative; Not to Scale)
Type PCB-
Mounted LEDs
Mounted LEDs
Collimated LEDs for Microscopyb Fiber-
Coupled LEDs
High-Power LEDs for Microscopy Multi-Wavelength
LED Source Optionsd
  • Measured at 25 °C
  • These Collimated LEDs are compatible with the standard and epi-illumination ports on the following microscopes: Olympus BX/IX (Item # Suffix: -C1), Leica DMI (Item # Suffix: -C2), Zeiss Axioskop (Item # Suffix: -C4), and Nikon Eclipse (Bayonet Mount, Item # Suffix: -C5).
  • Typical power when used with MM Fiber with Ø400 µm core, 0.39 NA.
  • Our Multi-Wavelength LED Sources are available with select combinations of the LEDs at these wavelengths.
  • Typical power for LEDs with the Leica DMI collimation package (Item # Suffix: -C2).
  • Minimum power for the collimated output of these LEDs. The collimation lens is installed with each LED.
  • Typical power for LEDs with the Olympus BX and IX collimation package (Item # Suffix: -C1).
  • Typical power for LEDs with the Zeiss Axioskop collimation package (Item # Suffix: -C4).
  • Percentage of LED intensity that emits in the blue portion of the spectrum, from 400 nm to 525 nm.
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Cage-Compatible LED Backlight

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LEDBW1 Support Documentation
LEDBW16500 K, 251 mW (Min) 30 mm Cage-Compatible Diffuse Backlight LED, 2000 mA