Depending on the requirements, the specular reflections of an object ("specular highlights") can be intensified or attenuated with beam illumination. This is also referred to as a bright field or dark field configuration.

Dark fieldmicroscopy

Samples observed under dark-field microscopy should be carefully prepared since dust and other particles also scatter the light and are easily detected. Glass slides need to be thoroughly cleaned of extraneous dust and dirt. It may be necessary to filter sample media (agar, water, saline) to exclude confusing contaminants. Sample materials need to be spread thinly; too much material on the slide creates many overlapping layers and edges, making it difficult to interpret structures.

Dark fieldexperience

Dark-field microscopy is ideally used to illuminate unstained samples causing them to appear brightly lit against a dark background. This type of microscope contains a special condenser that scatters light and causes it to reflect off the specimen at an angle. Rather than illuminating the sample with a filled cone of light, the condenser is designed to form a hollow cone of light. The light at the apex of the cone is focused at the plane of the specimen; as this light moves past the specimen plane it spreads again into a hollow cone. The objective lens sits in the dark hollow of this cone; although the light travels around and past the objective lens, no rays enter it.

Dark fieldFLIGHT

Dark-field microscopy has many applications in microbiology. It allows the visualization of live bacteria, and distinguishes some structure (rods, curved rods, spirals, or cocci) and movement.

Our Lighting Advisor provides individual product recommendations by guiding you step by step to a selection of suitable lighting and components. Select the lighting for your vision system as early as possible during your design process.

The right lighting is key for any image processing system. It helps determine whether an inspection task is handled efficiently or not.

Dark FieldDenver

The entire field appears dark when there is no sample on the microscope stage; thus the name dark-field microscopy. When a sample is on the stage, the light at the apex of the cone strikes it. The rays scattered by the sample and captured in the objective lens thus make the image.

The right lighting in a computer vision setup significantly impacts image processing results. Here, we explain the key factors that contribute to optimal lighting.

Dark fieldimmersive

Bar lights produce a narrow strip of light useful for inspecting long, thin workpieces or highlighting the edges of an object.

Application example: These very versatile lights can be used for many applications, including character recognition or quality inspection on long, thin workpieces.

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The right illumination is critical in a vision system. Properly combining lighting with the camera and lens ensures the best possible results in your application.