Biophotonics I W. Petrich

Transcription

1 Biophotonics I W. Petrich Slides of lecture #04 November 6 th, Lecture Biophotonics I will be credited with 2 CP subject to successfully passing the exam There will be a written exam ( Klausur ) on February 5th 2018 registration: Prof. Dr. Petrich Biophotonics I (WS 2017/18) 1

2 SUMMARY of lecture#3 ( refractive errors of the human eye Myopia ( Kurzsichtigkeit ) correction: defocusing lens (negative refractive power) Hyperopia ( Weitsichtigkeit ) correction: focusing lens (positive refractive power) Presbyopia ( Altersweitsichtigkeit ) correction: focusing lens (positive refractive power) I.1.4. sensing A) receptor density Resolution due to sensor density at fovea centralis: ~1 B) rods and cones C) biochemistry and time resolution From: chm.bris.ac.uk rods cones vision scoptic photopic total number [Mio.] density@ 0 [mm - ²] ~ density@ 20 [mm - ²] Wavelength of max. sensitivity [nm] ~ , 530,560 Color vision No Yes Sensitivity high low Response time fast slow Retinal pathway convergence high lower Prof. Dr. Petrich Biophotonics I (WS 2017/18) 2

3 Ferry-Porter law: Critical flicker frequency proportional to logarithm of luminescence Prof. Dr. Petrich Biophotonics I (WS 2017/18) 3

4 the brain makes the image From: H. Gross (Ed.), Handbook of Optical Systems, Vol 4: Survey of Optical Instruments, Wiley-VCH 2008 Prof. Dr. Petrich Biophotonics I (WS 2017/18) 4

5 the brain makes the image From: H. Gross (Ed.), Handbook of Optical Systems, Vol 4: Survey of Optical Instruments, Wiley-VCH 2008 Prof. Dr. Petrich Biophotonics I (WS 2017/18) 5

6 the brain makes the image From: H. Gross (Ed.), Handbook of Optical Systems, Vol 4: Survey of Optical Instruments, Wiley-VCH 2008 Prof. Dr. Petrich Biophotonics I (WS 2017/18) 6

7 D) attempts towards color metrics RGB chart using the original 1931 colors Mix of intensities of the original 1931 colors to track the outer horseshoe line: Prof. Dr. Petrich Biophotonics I (WS 2017/18) 7

8 Biophotonics I D) attempts towards color metrics CIE Normfarbtafel Prof. Dr. Petrich Biophotonics I (WS 2017/18) 8

9 Prof. Dr. Petrich Biophotonics I (WS 2017/18) 9

10 Ophthalmology 119(4) doi: /j.ophtha Prof. Dr. Petrich Biophotonics I (WS 2017/18) 10

11 visual acuity and 20/20 vision 1 arc minute 20 ft ~ 6m 1.75mm Ophthalmology 119(4) doi: /j.ophtha Prof. Dr. Petrich Biophotonics I (WS 2017/18) 11

12 Prof. Dr. Petrich Biophotonics I (WS 2017/18) 12

13 Figure 1) Detailed view of the subretinal implant on the microchip, which for its part has 1,500 pixels on a surface area of 3 3 mm. The chip consists of 1,500 microphotodiodes, each of which is connected to an amplifier and an electrode. Each microphotodiode collects the incident light signal, and an amplified electrical signal is sent by the electrode to the bipolar cells. The entire implant consists of the subretinal chip, a power supply cable (polyimide film and a thin silicone cable with gold wires), and the secondary coil, which is affixed to bone in the retroauricular region. Prof. Dr. Petrich Biophotonics I (WS 2017/18) 13

14 Proc. Roy Soc. B 280 (2013) Prof. Dr. Petrich Biophotonics I (WS 2017/18) 14

15 REMINDER: magnifying glass Magnification: B 1 B G 1 G M tan BB1 b l tan b l GG with 1 f 1 b 1 g 1 1 M b f b 1 b f 1 b g it follows that if b ~ s >> f the magnification M becomes b g l M s f s Example: D = +20D f = 5 cm with s = 25 cm the magnification becomes M = 5 ( 5x or x5 ) Prof. Dr. Petrich Biophotonics I (WS 2017/18) 15