1. An image pickup device comprising:
sensing elements arranged in a matrix;
a digital counter; and
an AD converter provided for each column of said sensing elements,
wherein each AD converter first retains in a memory unit as an initial value an electric signal corresponding to a signal of a corresponding sensing element, which is an analog signal, and said AD converter then initiates charge or discharge of said memory unit at a rate corresponding to a magnitude of an input fixed signal, measures a time period from either a charge start time or a discharge start time until said electric signal of said memory unit becomes equal to a reference signal, and recognizes said measured time period as a digital value,
wherein each AD converter includes an integrator, a comparator, and a digital memory,
wherein an output of said integrator is connected to an input of said comparator, an output of said comparator is connected to a loading trigger terminal of said digital memory, and
wherein said digital counter is connected to an input terminal of said digital memory, and output from said digital counter is stored in said digital memory is the digital value.
2. The image pickup device according to claim 1, wherein said initial value is determined by integrating for a certain period of time said signal of said corresponding sensing element with said integrator, and a determined initial value is either charged or discharged using said integrator.
3. The image pickup device according to claim 2, wherein said memory unit is an output portion of said integrator.
4. The image pickup device according to claim 1, wherein said integrator includes an operational amplifier, a resistor connected to an input terminal of said operational amplifier, and a capacitor connected between said input terminal and an output terminal of said operational amplifier.
5. The image pickup device according to claim 1, wherein said integrator includes an operational amplifier and a switched capacitor circuit, which is connected to an input terminal of said operational amplifier.
6. The image pickup device according to claim 1, wherein sensing elements arranged in a column direction are selectively connected to a vertical output line, and said vertical output line and a corresponding AD converter are connected via a voltage amplifier.
7. The image pickup device according to claim 1, wherein
sensing elements arranged in a column direction are selectively connected to a vertical output line,
said vertical output line and a corresponding AD converter are connected via a noise reduction circuit, and
said noise reduction circuit has a function to reduce a noise signal of said signal from said sensing element after sensing.
8. The image pickup device according to claim 1, wherein reading of a row is commenced prior to conclusion of outputting of a signal of another row after sensing from an AD converter.
9. An image pickup device according to claim 1, wherein said image pickup device is incorporated in an image pickup system that includes an optical system, which focuses light to said image pickup device, and a signal processing circuit, which processes an output signal from said image pickup device.
10. The image pickup device according to claim 1, wherein a process of either re-charging or re-discharging in order to ensure that an electric signal exceeding said reference signal reaches said reference signal is repeated more than twice.
11. The image pickup device according to claim 1, wherein a process of either re-charging or re-discharging, in order to ensure that an electric signal exceeding said reference signal reaches said reference signal, is conducted through a synchronous operation of two or more AD converters provided for each column of said sensing elements.
12. An image pickup device comprising:
sensing elements arranged in a matrix;
a digital counter; and
an AD converter provided for each column of said sensing elements,
wherein each AD converter includes a memory unit, retains in said memory unit as an initial value an electric signal corresponding to a signal of a corresponding sensing element, which is an analog signal, initiates charge or discharge of said memory unit by a subsequently input first fixed signal, measures a time period from a start of said charge or said discharge until said electric signal of said memory unit becomes equal to a reference signal, initiates charge or discharge of said memory unit by a subsequently input second fixed signal, measures a time period for an electric signal exceeding said reference signal of said memory unit after measurement becomes equal to said reference signal, and recognizes the measured time period as a digital signal,
wherein each AD converter includes an integrator, a comparator, and a digital memory,
wherein an output of said integrator is connected to an input of said comparator, an output of said comparator is connected to a loading trigger terminal of said digital memory, and
wherein said digital counter is connected to an input terminal of said digital memory and output from said digital counter is stored in said digital memory as the digital value.
13. The image pickup device according to claim 12, wherein said first fixed signal is same as said second fixed signal.
14. The image pickup device according to claim 12, wherein sensing elements arranged in a column direction are selectively connected to a vertical output line, and said vertical output line and a corresponding AD converter are connected via at least a voltage amplifier.
15. The image pickup device according to claim 12, wherein
sensing elements arranged in a column direction is selectively connected to a vertical output line,
at least a noise reduction circuit is connected between said vertical output line and a corresponding AD converter, and
said noise reduction circuit has a function to reduce a noise signal of said signal from said sensing element after sensing.
16. The image pickup device according to claim 12, wherein a differential voltage of said electric signal exceeding said reference signal and said reference signal is amplified by an amplifier prior to being charged or discharged.
17. The image pickup device according to claim 16, wherein said differential voltage of said electric signal exceeding said reference signal and said reference signal are retained in a first terminal, and said amplifying means voltage-amplifies said differential voltage retained in said first terminal via said amplifier after sample holding, and overwrites said differential voltage subsequent to said voltage amplification onto said first terminal.
18. The image pickup device according to claim 12, reading of a row is commenced prior to conclusion of outputting of a signal of another row of a digital data output operation after AD conversion.
19. An image pickup device according to claim 12, wherein said image pickup device is incorporated in an image pickup system that includes an optical system, which focuses light to said image pickup device, and a signal processing circuit, which processes an output signal from said image pickup device.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A power tool comprising:
a housing having an air intake hole and an air exhaust hole formed therein, the housing having an inner surface,
a brushless motor including:
a stator having an outer surface engaged with the housing, the stator having:
a cylindrical stator;
an insulating member fixed to the cylindrical stator; and
a coil fixed to the insulating member; and
a rotor rotatably disposed in the stator;
a fan fixed to the rotor; and
a circuit board directly fixed to the insulating member and electrically connected to the coil;
wherein the cylindrical stator is positioned between the circuit board and the fan.
2. The power tool according to claim 1, wherein the cylindrical stator, the insulating member, and circuit board define a first surface,
wherein the first surface and the inner surface define a ventilation path in the housing.
3. The power tool according to claim 1, wherein the circuit board is fixed to the insulating member by a screw.
4. The power tool according to claim 1, further comprising a permanent magnet fixed to the rotor; and
an element fixed to the circuit board and facing the permanent magnet for detecting a position of the rotor.
5. The power tool according to claim 1, wherein the housing includes a handle housing,
wherein the power tool further comprises:
a hammer;
an anvil;
a hammer case that is disposed in front of the motor and accommodates the hammer and the anvil;
a battery fixed to the handle housing.
6. The power tool according to claim 1, further comprising a switching element fixed to the circuit board.
7. The power tool according to claim 1, wherein the rotor is rotatably supported by the housing.
8. The power tool according to claim 1, wherein the inner surface has a plurality of ribs, the plurality of ribs contacting with the cylindrical stator.
9. A power tool comprising:
a motor housing having an air intake hole and an air exhaust hole formed therein, the housing having an inner surface and a front portion;
a brushless motor including:
a stator having an outer surface engaged with the housing, the stator having:
a cylindrical stator;
an insulating member fixed to the cylindrical stator; and
a coil fixed to the insulating member; and
a rotor rotatably disposed in the stator;
a hammer case that is disposed on the front portion of the motor housing;
a hammer accommodated in the hammer case and connecting the rotor;
an anvil accommodated in the hammer case and receiving an impact force from the hammer;
a circuit board directly fixed to the insulating member and electrically connected to the coil;
a handle housing extending downward from the motor housing and having a lower end; and
a battery fixed to the lower end of the handle housing,
wherein the stator is positioned between the circuit board and the fan.