The difference in reflection of objects by metallographic microscope illumination
1. Direct illumination: Light is directed directly onto an object to obtain a clear image. This type of light is very effective when we need to obtain objects with high contrast height. But when we use it to shine on bright or reflective objects, it can cause mirror reflection.
2. Dark field of view: Light is projected onto the surface of an object at an angle, resulting in slanted scattered light reaching the camera, creating bright points on a dark background or field of view. With this illumination method, if there is no color difference on the surface of the object, nothing can be seen through the visual system. These two observation methods are usually equipped in a metallographic microscope.
3. Back lighting: Light that emits a uniform field of view from the back of an object, and the side profile of the object can be seen through the camera. Back lighting is often used to measure the size of an object and determine its direction.
4. Scattered lighting: Reflective lighting, providing a soft, directionless light that resembles a dazzling shadow, suitable for highly reflective objects. Due to the effect of this lighting, we compare this light to calm, directionless light on cloudy days.
5. Coaxial lighting: The formation of a uniform surface light source emitting in a vertical direction, through a semi transparent mirror at a 45 degree angle, causes the light source to illuminate the surface of an object in a vertical downward direction. This type of light source is particularly helpful for detecting highly reflective flat objects.
usage method
1. Use a research dark field microscope, or remove the condenser from a regular optical microscope and replace it with a dark field condenser.
2. Whether using a dry objective or an oil immersed objective, a large drop of tar should be added to the upper lens of the condenser during mirror inspection.
3. Place the prepared bacterial suspension specimen slide on the stage and raise the condenser to the top to allow the oil to come into contact with the slide.
4. Zoom in on the light source.
5. Adjust and focus the optical axis of the spotlight. Use a 10 * objective lens to find the object being tested, turn down the iris aperture of the condenser until the outline of the field of view aperture can be seen in the field of view, and then slowly adjust the condenser up and down to make the image of the field of view aperture clearer. If the field of view aperture is not in the center of the field, use the two adjustment buttons on the outside of the condenser to adjust it. When the bright light point is adjusted to the center of the field, turn it up again to observe.
