Virtual picture
In optics, a virtual image of a light- reflecting or luminous object is an optical image that, in contrast to a real image , cannot be displayed on a screen at the place where it appears. With converging lenses , it occurs when the object is between the focal point and the lens .
No rays of light emanate from the location of the virtual image (hence the term "virtual"), but the rays seem to come from the image, since our perception assumes that the rays of light are straight and , if necessary, extends the ray that hits the eye backwards.
Examples are:
- The reflection in a flat mirror . It is behind the mirror (even if there is a wall there) at the same distance as the object and is the same size as this (even if the mirror is much smaller).
- The magnifying glass image that a collecting lens creates from an object within the focal length .
- The image that is created through the eyepiece of a light microscope . Analogous to the magnifying glass, the eyepiece enlarges the real intermediate image that is generated by the objective.
- The image that you see of an object when you look at it through a diverging lens .
literature
- Eugene Hecht: Optik , Oldenbourg, 5th edition 2009, ISBN 978-3-486-58861-3 . P. 259
- Wolfgang Zinth, Ursula Zinth: Optics light rays - waves - photons. Oldenbourg Verlag Munich, 4th edition 2013, ISBN 978-3-486-72136-2 . P. 87