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Light, the Eye and Optics. Light aka Visible Electromagnetic Radiation.

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Presentation on theme: "Light, the Eye and Optics. Light aka Visible Electromagnetic Radiation."— Presentation transcript:

1 Light, the Eye and Optics

2 Light aka Visible Electromagnetic Radiation

3 Wavelength ≈ 1/Frequency

4 Visible Spectrum: 400-700 nm

5

6 6   Visibility as a Function of WaveLength (V   Light Adapted Eye)

7 Why 400-700 nm?

8 Visible Spectrum (400-700 nm) versus Nature of Sunlight

9 Polarization (Orientation of Electric Field)

10 Light Facts Speed of Light 186,000 miles/s; 300 Million m/s (psychologically instantaneous) Energy in light is wavelength dependent E = h * frequency = h * 1/wavelength (shorter wavelengths have greater energy) Psychological light measurement units: LUMEN Total light “flux” emitted by a source (WATTS x Visibility Function) LUX Illumination (Light distribution falling on a surface) (lumens/m 2 ) LUMINANCE Light from reflective surface as captured by the eye (lumens/sr/m 2 ) candela/m 2 (nit)

11 Refraction of Light Bend toward normal entering dense medium. Bend away from normal leaving dense medium. Snell’s Law: sin θ 1 /sin θ 2 = n 2 /n 1 …… n 1 sin θ 1 = n 2 sin θ 2 http://en.wikipedia.org/wiki/Snell's_law http://en.wikipedia.org/wiki/Snell's_law

12 The Human Eye

13 Six Extraocular Muscles

14 The Human Eye

15

16 Physiological Optics

17 Power of Lens Increases with Curvature

18 Refraction of Light Bend toward normal entering dense medium. Bend away from normal leaving dense medium. Snell’s Law: sin θ 1 /sin θ 2 = n 2 /n 1 …… n 1 sin θ 1 = n 2 sin θ 2 http://en.wikipedia.org/wiki/Snell's_law http://en.wikipedia.org/wiki/Snell's_law

19 Accommodation of the Lens (Variable Focal Length)

20 Refractive States of the Eye Emmetroia Hyperopia Myopia (Astigmatism)

21 Hyperopia

22 Myopia

23 Corneal Astigmatism

24 Simulated Astigmatism

25 “Correcting” Astigmatism with Spherical Lenses

26 End


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