Biomedical Engineering Reference
In-Depth Information
Photoelectrical response
Element absorbance
1.2
1
0.8
0.6
0.4
0.2
0
400
500
600
700
(a)
Wavelength (nm)
Photoelectrical response
Element absorbance
1.2
1
0.8
0.6
0.4
0.2
0
400
500
600
700
(b)
Wavelength (nm)
Photoelectrical response
Element absorbance
1.2
1
0.8
0.6
0.4
FIGURE 16.6
Action spectra for (a) wild-type, (b) 4-keto, and
(c) 3,4-didehydro BR-PVA photosensor based
on the amplitudes of the PER. The dashed lines
denote the uncorrected absorption spectra of
the photosensors.
0.2
0
400
500
600
700
(c)
Wavelength (nm)
16.5.3.2 Imaging Array Electronics
The design principles are the same as for the photosensors, although the amplification is
increased to 980 because of expected degradation of the PER. The response is amplified
with an instrumentation amplifier (INA126), and the peak photovoltage is stored in a
small capacitor as shown in Figure 16.10. A microcontroller (PIC17C43) is used to digitize
the stored charges and transfer them to a computer for postprocessing (36).
