Television – Camera – system and detail – Solid-state image sensor
Reexamination Certificate
1998-03-12
2003-01-28
Garber, Wendy R. (Department: 2712)
Television
Camera, system and detail
Solid-state image sensor
C348S294000, C348S303000, C348S308000
Reexamination Certificate
active
06512543
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a physical quantity distribution sensor, a method of driving said sensor and a method of producing said sensor.
Recently, there is increased a demand for a semi-conductor device for sensing the spatial distribution of a physical quantity in a variety of fields. Particular attention is placed on a solid-state imaging device for sensing a light quantity as the physical quantity. More specifically, such a so-called amplifier-type solid-state imaging device is designed in the following manner. A plurality of storage sections are arranged to store a signal electric charge obtained through photo-electric conversion at the associated one of a plurality of photoelectric conversion sections. Each storage section is connected to the operation control portion of a transistor such as the gate of a field-effect transistor (FET) or the base of a bipolar transistor, or provision is made such that the storage section also serves as an operation control section. Accordingly, an electric current flowing in each transistor is controlled based on that potential of the associated storage section which varies with the amount of a signal electric charge.
With reference to
FIG. 12
, the following description will discuss the arrangement and operation of a physical quantity distribution sensor of prior art with an amplifier-type solid-state imaging device taken as an example.
As shown in
FIG. 12
, pixels
2
are arranged in a plurality of rows and a plurality of columns in an imaging region (generally, a region in which a physical quantity is to be sensed and stored)
1
. Each pixel
2
comprises a photoelectric conversion/storage section
3
and a driving transistor
5
having a gate
4
.
A selected-row-driving transistor
10
is disposed in each selected-row-driver
8
, and a voltage is to be supplied to each selected-row-driving transistor
10
from a selected-row-driving-voltage input portion
9
. Whether or not each selected-row-driving transistor
10
is electrically conductive, is controlled by a voltage of each output portion
7
of a shift register for row selection
6
. An output of a selected-row-driving transistor
10
is connected to a plurality of row-select-transistors
12
arranged in the row through one of row selection lines
11
, which allows a single pixel row to be selected out of the plurality of pixel rows.
The row-select-transistors
12
arranged in the same column are connected to a corresponding one of load transistors
14
through one of vertical signal lines
13
. The output potential of each photoelectric conversion/storage section
3
varies with the amount of signal electric charge stored therein. The output potential of each photoelectric conversion/storage section
3
is given to the gate
4
of a corresponding driving transistor
5
which is connected to one of power supply lines
17
. There is formed a source follower circuit in which the driving transistor
5
serves as a driving transistor and in which the load transistor
14
connected to a second power supply voltage (Vss) terminal
15
and to a gate input portion
16
, serves-as a load transistor. A power supply voltage.(Vdd) is supplied to each power supply line
17
from a first power supply voltage (Vdd) terminal
27
.
An output of the source follower circuit including the driving transistor
5
and the load transistor
14
is supplied to one of horizontal signal lines
24
through a signal column selection transistor
23
disposed in the associated one of column selection drivers
22
. Whether or not signal column selection transistors
23
are electrically conductive, is controlled by voltages generated at output portions
21
of a shift register
20
for column selection. According to this control, a single pixel column is selected out of the plurality of pixel columns. An output of the source follower circuit in a selected column, is selectively sent to an impedance conversion section
25
through the horizontal signal line
24
, and then supplied to an output portion
26
through the impedance conversion section
25
.
After the signals are read out from all the pixels
2
arranged in the selected row, a reset voltage input portion
28
sends a reset voltage to the selected-row-reset-driving transistor
29
in the selected-row-driver
8
for the selected row, thereby to drive the pixel reset transistors
30
in the selected row through a pixel-reset-voltage-supply line
19
associated with the selected row. This resets the signal electric charges stored in the photoelectric conversion/storage sections
3
in the selected row. Then, these photoelectric conversion/storage sections
3
again start storing signal electric charges.
According to the above-mentioned arrangement of prior art, each pixel has a photoelectric conversion section and an electric charge storage section, or a photoelectric conversion/storage section
3
having both conversion and storage functions as in the above example, a row-select-transistor
12
, a driving transistor
5
for amplifying an output of the photoelectric conversion/storage section
3
, and a reset transistor
30
for resetting the electric charge stored in the electric charge storage section or the photoelectric conversion/storage section
3
. Further, there are required a number of input/output lines such as the power supply lines
17
for driving transistors, the row-select-lines
11
, the pixel-reset-voltage-supply lines
19
, the vertical signal lines
13
and the like.
This complicates each pixel in arrangement and makes it difficult to enhance the performance thereof. It is also difficult to reduce each pixel in area to increase the number of pixels in the same area and to reduce the device in size.
In view of the foregoing, it is an object of the present invention to provide a physical quantity distribution sensor reduced in the number of input lines connected to pixels to simplify the pixels in arrangement, thus enabling to increase the number of pixels in the same area and to reduce the device in size.
SUMMARY OF THE INVENTION
The present invention provides a physical quantity distribution sensor comprising: a plurality of sensor/storage sections each having a sensor element for sensing a received physical quantity and a storage element for storing the information of physical quantity sensed by the sensor element; a selector for selecting at least one of the plurality of sensor/storage sections; and a plurality of buffers each capable of detecting and supplying the information stored in at least one selected sensor/storage section, and wherein there is disposed at least one selection signal transfer line for transferring an output of the selector, that power supply input portions of the buffers are connected to the selection signal transfer line, and that the buffers are operated using, as a power voltage, an output of the selector entered into the buffers through the selection signal transfer line.
The present invention provides another physical quantity distribution sensor having a plurality of unit cells arranged in N rows and M columns (each of N and M being a natural number not less than 2), each of the plurality of unit cells comprising (i) a sensor/storage section having (a) a sensor element for sensing a physical quantity and (b) a storage element for storing the information of physical quantity sensed by the sensor element, and (ii) a reset element for resetting the storage element, and this physical quantity distribution sensor is characterized in that there are disposed: a row selector for selecting one row out of the N rows; buffers in the M columns each for detecting and supplying the information stored in the storage element of the sensor/storage section in a selected row; and N selection signal transfer lines each for transferring an output signal of the row selector to each of the N rows, and that power supply input portions of the buffers in the M columns are connected to the N selection signal transfer lines and arranged to receive a power voltage through the selection signal tran
Kuroda Takao
Masuyama Masayuki
Garber Wendy R.
Matsushita Electric - Industrial Co., Ltd.
McDermott & Will & Emery
Nguyen Luong
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