Image Processing Reference
In-Depth Information
Micro lens
Color filter
Light
shield
OPF
Photodiode
Si
Transistor
Interconnect
Si
(a)
(b)
FIGURE 5.74
Comparison of schematic structures: (a) silicon-based PD; (b) OPF-based PD. (Reprinted with permission from
Isono, S., Satake, T., Hyakushima, T., Taki, K., Sakaida, R., Kishimura, S., Hirao, S. et al.,
Proceedings of the 2013
IEEE International Interconnect Technology Conference, paper ID
3030, 2013.) Copyright [2013] by the Japan Society
of Applied Physics.
ML
OCF
Transparent
electrode
Protecting film
OPF
Pixel
electrode
Metal layers
Pixel circuit
FIGURE 5.75
A cross-sectional schematic of pixels. (Reprinted with permission from Mori, M., Hirose, Y., Segawa, M.,
Miyanaga, I., Miyagawa, R., Ueda, T., Nara, H. et al.,
2013 Symposium on VLSI Technology
, 2-4, pp. 22-24, Kyoto,
2013.) Copyright [2013] by the Japan Society of Applied Physics.
feedback amplifier (FBA) circuit
65
is employed, as shown in Figure 5.77, with a pixel circuit
and timing diagram shown in Figure 5.77a and (b), respectively.
An FBA is composed of a differential amplifier and a source follower buffer (not
shown in the figure). During the reset period, a tapered reset signal is applied to the
reset gate, which lowers the cutoff frequency of the low-pass filter (LPF). A reset opera-
tion is carried out by monitoring the signal level,
V
sig
, which is the output of the reset
