An eyepiece located at the near end of the microscope tube. Often a simple Huygens eyepiece, though other varieties (negative eyepieces, flat field projection eyepieces) are common, depending on application.
SPHERICAL VS. ASPHERIC LENSES
HOW THEY’RE USED IN IMAGING APPLICATIONS
Optical Lenses are often categorized by their shape. Two common surface shapes are spherical and aspherical. Each offers unique characteristics that make it suitable for different use cases.