The pT-100 is a compact and simple-to-use LED illumination system for transmitted light applications, including brightfield, darkfield, DIC, Dodt gradient contrast and phase contrast.

The system is available in four variants to bring the benefits of LEDs to modern laboratories. A broad white system provides a safer and convenient alternative to halogen by reducing harmful UV exposure to the eyes and is ideal for long hours spent at the microscope, while three narrow bandwidth options (525, 635 and 770 nm) optimise image quality through increased contrast. The pT-100-WHT and pT-100-770 nm are also available as variants with a 3 mm liquid light guide attachment, which is ideal for electrophysiology applications.

CoolLED pT100 Spectrum Graph

Utilising the highly successful pE-100wht technology, we have further developed our LED solutions for Transmitted Light Applications with the pT-100 range.  Whether you’re looking for a broad white 100 W halogen replacement or want to optimise the quality of your images through the use of narrower spectrum wavelengths, the pT-100 can meet your needs.

CoolLED LED illumination technology offers a host of benefits over halogen systems, with instant on/off and irradiance control in 1% steps from the ergonomically designed manual control pod which can be positioned close at hand. Remote control is also available via a TTL trigger.

A true 100 W Halogen replacement: pT-100-WHT

Laboratories familiar with halogen lamps will find that CoolLED’s broad white achieves results which make the move to LEDs simple and apparent.  Colour temperature remains constant as irradiance is increased which makes colour balancing unnecessary and improves standardisation between sessions. Samples will appear identical even though irradiance could be up to five times greater.

In addition, the pT-100-WHT does not produce unwanted light in the UV which makes it safer and more comfortable, as risk of eye damage is significantly lower.

    Narrow bandwidth solutions eliminate background noise

    White light LED systems using a phosphored LED can be a source of background noise when used as a transmitted light source, which reduces image contrast. Narrow bandwidth illumination systems remove this background source to improve image quality and enhance analysis – even in thicker samples and applications requiring infrared light.

    • Higher contrast images: pT-100-525
      Narrow bandwidth at 525 nm is optimised for the spectral response of most scientific cameras and reduces background noise from a phosphored LED.
    • Revealing details in thick samples: pT-100-635
      Narrow bandwidth at 635 nm provides deeper penetration, which is excellent for revealing detail in thicker samples.
    • Infrared illumination of thicker samples: pT-100-770
      Narrow bandwidth at 770 nm provides deeper sample penetration techniques that require the use of infrared light.
    CoolLED pT100 narrow bandwidths
    Liquid Light Guide for added flexibility

    The pT-100-WHT and pT-100-770 nm are also available with a 3 mm liquid light guide as an alternative to using a direct attachment adaptor, offering two main benefits:

    • Enhancing accuracy of sensitive electrophysiology experiments as remote positioning allows the Illumination Systems to be placed outside of a faraday cage, avoiding electrical interference.
    • Added compatibility with microscopes which only feature a liquid light guide input, the collimating optics being an integral part of the microscope.


    • Comfortable operation and reduced risk of eye damage as no unwanted UV
    • Spectral performance matched to 100 W halogen, creating consistent images
    • No variation in colour across irradiance range, removing the need to colour balance
    • Replaces 100 W halogen lamp housing on most current and older microscopes – quick & easy exchange
    • LLG version enhances accuracy for electrophysiology applications


    • A phosphor-free illumination centred around 525 nm optimised for the spectral response of most scientific cameras
    • Improved image contrast compared to white light source


    • A phosphor-free solution for brightfield imaging with a peak of 635 nm providing deeper penetration in thicker samples
    • Reduced phototoxicity of light-sensitive samples


    • A specialised solution for IR contrast techniques such as DIC, Dodt contrast etc.
    • Centred around 770 nm provides the optimal output for deeper sample penetration techniques requiring infrared light
    • LLG version enhances accuracy of electrophysiology applications using thick tissue slices
    Plus all the benefits of LED illumination technology.

    The system comprises a pT-100 LED Light Source, control pod, and power supply.

    Power requirements
    100-240 V a.c. 50/60 Hz

    Power consumption
    1 W (standby)
    20 W (full irradiance)

    pT-100 Light Source (direct fit): 66 mm (diameter) x 128 mm(l) Weight 0.42 kg
    pT-100 Control Pod: 102 mm(w) x 110 mm(d) x 50 mm(h) – Weight 0.55 kg
    pT-100 Power supply: 55 mm(w) x 95 mm(d) x 40 mm(h) – Weight 0.19 kg

    Environment & Safety
    • Mercury-free & Laser-free
    • Energy Efficient
    • Long lifetime
    • No bulb replacements
    • Quiet operation
    • No special disposal regulations or issues
    • Reduced risk of eye damage.  Care should be taken when viewing samples using the microscope eyepiece while the transmitted light source is switched on. Users should select the lowest irradiance setting on the pod before using the eyepiece and increase irradiance as necessary.

    Control pod for operation and access to settings and usage history.

    Manual control for instant on/off and irradiance control in 1% steps from 0 – 100%

    Via single TTL for on/off control using a BNC connection on the control pod.  Triggering speed <150 µs

    Direct fit to a microscope

    Specify a Microscope Adaptor from CoolLED’s range of transmitted port microscope adaptors.


    Industry-leading 36 months. Read more here. 

    All data correct at time of publication

    pT100wht SpectComparisonGraph Oct18 002 1024x605 1

    We are often asked about the power, intensity or irradiance of CoolLED Illumination Systems. The answer is not as simple as you might believe from many websites and data sheets, and it can be difficult to compare data from these sources as measuring set ups differ.

    Photons are also lost as light travels from the light source to sample plane. The only way to objectively compare light sources is by measuring irradiance at the sample plane.  To understand why we use the term irradiance and how to measure and compare light sources with accuracy and precision, download our white paper. Or please contact us if you have further questions.


    For performance data, please contact us

    • We were advised to purchase the pT-100 to replace a light source on an older Leica microscope and have not been disappointed.  Set-up was simple and I was able to carry out the installation myself without difficulty.  We work with plant material and micro fungi, and have found the quality of the light produced to be ideal for our purposes. The range and incremental nature of the brightness settings is of particular benefit for the different scientists that use that microscope.  We will certainly look at this unit again when the requirement arises.

      James Holmes, UK (pT-100)

    • For temperature sensitive applications such as ours, we strongly recommend changing conventional halogen-driven transmitted light sources for LED units such as the pT-100-WHT.

      Dimitri Kalleas & Alex Laude, Newcastle University (pT-100)

    • The key improvement in switching to the CoolLED is the field of view is more evenly illuminated than with the original 100 w tungsten halogen bulb.

      Dr. Ronald Harris, Harris Innovation, USA (pT-100)

    • Set up was very easy and pT-100 Light Source was simple to operate. LEDs gave nice even illumination at 2% power. Higher powers were not necessary due to the brightness of the LED: 2% power with 5 ms or 10 ms exposure. There were no obvious signs of cell stress due to light toxicity over the duration of the 60 min or 180 min experiments I ran. Overall they are neat, simple to use and very efficient.

      Tim Self, Head of School of Life Sciences imaging (SLIM), University of Nottingham, UK (pT-100)

    CoolLED for Optogenetics

    CoolLED for Optogenetics

    CoolLED Multi-Wavelength LED Microscopy Illumination

    CoolLED Multi-Wavelength LED Microscopy Illumination

    No optical filter sets for this product
    pT-100-XXX-YYY-ZZ: pT-100 direct fit Light Source, interchangeable microscope adaptor to customer-specified microscope, remote manual control pod, and power supply.
    pT-100-XXX-L15-ZZ: pT-100 Illumination System includes Light Source, Control Pod, 1.5 m long, 3 mm diameter liquid light guide & ZZ Plug.
    Select from 770 nm or WHT (White) Transmitted Illumination ONLY.
    pT-100-XXX-L3-ZZ: pT-100 Illumination System includes Light Source, Control Pod, 3 m long, 3 mm diameter liquid light guide & ZZ Plug. Select from 770 nm or WHT (White) Transmitted Illumination ONLY.

    To specify wavelength (XXX):  select from WHT, 525, 635, or 770

    To specify microscope code (YYY): see Adaptors

    To specify power cable (ZZ):  10 = Australia, 20 = Europe, 30 = UK, 40 = USA



    No imaging software available for this product