LED brings great changes to the optical microscope industry

by:ALLTOP      2020-02-13
At present, in the microscope, the existing light source is shi ying- Halogen incandescent lamps, currently LED is entering the microscope, because halogen sources usually consume 50 W-100 W. However, it can be seen that halogen sources are still very advantageous. They are essentially blackbody radiators. LED light sources can be customized to provide the correct quality of light for professional tasks. At present, in the microscope, the existing light source is shi ying- Halogen incandescent lamps, currently LED is entering the microscope, because halogen sources usually consume 50 W-100 W. However, it can be seen that halogen sources are still very advantageous. They are essentially blackbody radiators. This means that they produce a continuous spectrum without any bulge, so any object of any visible color can be seen and any visible color can be separated by optical filtering. Clive Beech, Component Manager of Plessey, a British LED manufacturer, said the advantage of halogen is that it is a good broad-spectrum light source. The spectrum is very uniform and the color is very good. Each has its own strengths, and the optical microscope is not complete. Some microscopes do the same work every day, such as counting white blood cells, requiring a narrow range of illumination. The others are common, in which the required number of lighting options is more. The observer may look directly at the eyepiece or connect to the display of the microscope camera. Researchers sometimes need excellent and accurate color rendering performance, requiring high contrast between what they are looking for and what they are not interested in, thus requiring a good combination of spectrum and lighting direction. The problem with halogen is to protect the sample from heat. Beech said: it has a high load of infrared rays, which is harmful to any tissue sample or organic material, so you must filter it out. The LED avoids this layer of filtration because the standard blue core plus phosphor technology does not produce IR. Plessey optical designer Samir Mezouari said that most can simulate blackbody emission spectra. But the challenge is how to get good performance. Sufficient optical power is also in place. Beech said: our standard white LED is 12V 8W 1000 lm and the lens is in a 7x 7mm package. The four connection points of the device are laid flat on a single chip with square faces, with almost no gaps between emitters, thus eliminating artifacts. LED brings about transformation. Although more current is needed, large-size chip LED is also possible, and the size or quantity of chip joint lines needs to be increased. These are potential problems with microscope illumination. Even if Kohler illumination minimizes this effect, the residual image of the light source structure may be superimposed on the view of the object. Even if the necessary joint lines are used, the light from the LED source is stronger than that from halogen lamps. For very sensitive samples, LED can be used for Micro flash photography to further reduce heat and infrared rays. Beech said: you cannot divide halogen by reducing energy input, but you can use LED. Light can be captured by a camera that is always on, and samples that cannot be captured by a halogen bulb can be imaged by an LED. It is also easier to use LED for space lighting. For example, Leica makes the LED ring pass through the objective lens of the reflection microscope, which can generate light from only one angle and display surface features. Due to the long service life of the LED, the LED can be built into the optical instrument, thus avoiding the steps of rearrangement and calibration required when replacing halogen bulbs and saving space, there is no need to replace the bulb's finger space and less heat dissipation space. The contrast enhancement step is to replace halogen with LED of continuous spectrum. For contrast enhancement, some microscopes contain switchable optical filters that can be replaced by LEDs of various wavelengths. Beech said that you can't always want to image with a uniform spectrum. For example, with blue light illumination, the red light sample component will become darker, thus increasing the contrast. He added that with LED, you can make a wide spectrum of phosphor. Especially for pathology, I will choose the wavelength. Mezouari said: imagine red, green, blue and white LEDs emitting some broad spectrum peaks with specific wavelengths. Then, for example, you can turn off red and find the spectral formula of the specific sample you want. Camera digital image processing is an important part of microscope. Mezouari believes that highly enhanced images can be obtained by combining images taken at different wavelengths. Which wavelength of LED to choose depends on the work at hand, but if a camera is used, Beech recommends matching red and green with blue light and RGB filtering of the camera chip. In extreme situation under only 'with LED existing of or will halogen most energy filter out get of short-wave long (Blue)Light can provide higher resolution. There is also some evidence that long-term exposure to intense blue light may have adverse effects on human eyes. LED light source, before science becomes clearer, when the operator may expose himself to strong light, at this time, the preventive measure may be to limit the light source to halogen analog or green wavelength or longer wavelength. For severe short-term exposure, there is already a light bio-safety standard. Completely canceling spectral illumination may be an error because a sample may only include a monochromatic material that is inconsistent with the light source. For multi-wavelength LED light sources, the light must be combined in some way. Mezouari said: you can use a miniature LED array with a small diffuser to obtain hundreds instead of thousands of lumens, but it is enough. If you have enough space, use a separate LED and a few centimeters long mixing rod. Or if you only have red, green and blue, you can use PRISM reflectors to mix and sometimes add mixing rods.
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