Often high-powered microscopes cannot provide excellent quality images due to incorrect use of light sources, which generally leads to inadequate illumination of the object. You should keep in mind that any properly illuminated specimen should be free of glare and the light should be evenly dispersed in the field of view.
What are the main sources of illumination for a microscope?
- Halogen Lamps: Halogen illumination provides white light, which is recommended for most uses of miscroscopes. But since it is a hot type of light, it is not a good idea to use it for observing live specimens.
- LED lamps: Using a microscope with LED illumination is a good alternative to halogen, since the light emitted has a blue hue and the temperature does not affect the object being illuminated.
- Ultraviolet Light Lamps: In a microscope that uses ultraviolet light, it obtains radiation with a wavelength of approximately 200 nm, which provides greater resolving power than visible light. This type of illumination is invisible to the human eye, it is not captured by the retina and it is also very harmful; that is why the image is not observed directly, on the contrary it must be visualized by fluorescence, photography or a digital sensor.
How do LED lamps work?
LED technology offers numerous advantages that also bring enormous benefits in microscopy. A light emitting diode (LED) is a semiconductor device that emits light when a voltage is applied to its terminals (electroluminescence). Unlike conventional filament bulbs, LED sources are a “cool” light source (they do not generate any heat) and provide high intensity light similar to that of halogen bulbs. LED lamps require very little maintenance, and have a long life. They are also more efficient than tungsten bulbs in terms of the amount of energy they convert into light.
White LED light is particularly useful as an illumination source in microscopy and is produced by adding phosphors to blue LEDs. LED illumination can be placed in a ring-shaped microscope to allow multidirectional illumination.
What are the main applications of LED lighting?
LED lamps can produce bright white light of high intensity to produce excellent illumination for various imaging tasks. It has the advantage of being cool light, and therefore, cannot damage heat-sensitive samples or cause temperature-induced focus changes, which can impact the accuracy of metrology applications. The ability to select directional light from the LED illuminator ring provides opportunities to create shadows or edges for measurement and inspection applications. The system makes possible observations of extremely low-contrast edges that are usually invisible under episcopic illumination.
Advantages of LED illumination in the microscope
- Crisp, natural light for a variety of incident light applications.
- Consumes less energy.
- It lasts longer compared to halogen lamps, saving energy and money.