VLE 2 Optical Instruments I

Optics and optical technologies

Lecture 02:

Optical instruments I

1

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

Additional literature:

•Demtröder, W.: Experimentalphysik 2 – Elektrizität und Optik, Springer, 1999.

•Pedrotti, F.: Optik für Ingenieure, Springer, 2002.

•Hering, E.: Physik für Ingenieure, Springer, 2007.

•Gerthsen: Physik, Springer, 2009.

All books are available in the university network www.springerlink.de as *.pdf.

2

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

Overview

1.The human eye

2.Magnification glass

3.Telescope

4.Projector

5.Camera

6.Achromates

7.Optical light fibres

3

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

1. The human eye

4

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

Important parts

source: SAOT SA08

5

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

The eye as optical instrument

source: Uni Karlsruhe – Optische Systeme	source: Uni Karlsruhe – Optische Systeme
Eye	Brain
• Bad lens with many lens aberrations	• Correction of the aberrations

Adaptive optical instrument

•Different distances

•Huge dynamic range

6

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

Anatomy of the eye

Lens: bi convex, built from multiple layers

Cornea: main refractive power of the eye

Anterior chamber: filled with transparent liquid

Pupil: disc shaped aperture

Sclera: outer intransparent hull of the eye

Eye muscle: variation of the curvature of the eye lens

Retina: light sensitive layer of the eye

Rod cells: bright - dark

Fovea: zone of the best vision

Cone cells: colour vision

Optical nerve

Rod cells: bright - dark

		Vitreous humour: clear gel,
	Iris: changes the size
		variation of the curvature
				Source: Demtröder Experimentalphysik 2
		radius of the lens
	of the pupil

7

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

Blind Spot

Small experiment to prove the existence of the blind spot:

 Cover your left eye and fixate the X with your right eye

X

1

2

3

In dependence of you distance to the screen a few numbers will “disappear”.

The blind spot is not recognized in daily life because the brain merges it with the surrounding. Hence the white background leads to a white area at the blind spot.

8

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

Retina

Nerve layer
Light	Blood vessel	Cone cell

Rod cell

choroid

Ganglion cells	Bipolar cells	Nerve	fibre

Retina:

Light sensitive layer of the eye Cells: rods and cones

Rod cell:

Bright-dark vision

Very sensitive to light

Cone cell:

Colour vision

3 types for red, green and blue

Only in the Fovea

source: OSRAM

9

Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany

Ametropia

Short-sightedness/myopia

Normal sight

Far-sightedness/hyperopia

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Prof. M. Schmidt

Institute of Photonic Technologies, Univ. Erlangen, Germany