Image reading apparatus and semiconductor device
An image reading apparatus for reading an image includes a light receiving element that receives light from the image so as to perform photoelectric conversion, an amplifier which is electrically connected to the light receiving element, and amplifies a signal generated by photoelectric conversion, a switch element which is electrically connected to both ends of the amplifier so as to be parallel to the amplifier, a first capacitance which are electrically connected to both ends of the amplifier so as to be parallel to the amplifier, and a second capacitance which has one end which is electrically connected to one end of the light receiving element and one end of the amplifier. A second signal of which potential is changed after potential of a first signal input to a control terminal of the switch element is changed is applied to another end of the second capacitance.
1. An image reading apparatus for reading an image, the apparatus comprising:
a light receiving element that receives light from the image so as to perform photoelectric conversion;
an amplifier which is electrically connected to the light receiving element, and amplifies a signal generated by photoelectric conversion;
a switch element which is electrically connected to both ends of the amplifier so as to be parallel to the amplifier;
a first capacitance which is electrically connected to both ends of the amplifier so as to be parallel to the amplifier; and
a second capacitance which has one end which is electrically connected to one end of the light receiving element and one end of the amplifier,
wherein
a second signal of which potential is changed after potential of a first signal input to a control terminal of the switch element is changed is applied to another end of the second capacitance.
2. The image reading apparatus according to claim 1 , wherein
the second signal is a signal obtained by reversing a polarity of the first signal.
3. The image reading apparatus according to claim 2 , wherein
the second capacitance is capacitance between a first wire for electrically connecting one end of the light receiving element, one end of the amplifier, one end of the switch element, and one end of the first capacitance, and a second wire on which the second signal is propagated.
4. The image reading apparatus according to claim 3 , wherein
the first wire and the second wire are provided in the same wiring layer among a plurality of wiring layers provided on a semiconductor substrate.
5. The image reading apparatus according to claim 3 , wherein
the first wire has a first comb-tooth shaped portion,
the second wire has a second comb-tooth shaped portion,
first comb-tooth shaped portions and second comb-tooth shaped portions are provided so as to mesh with each other, and
the second capacitance is capacitance between the first comb-tooth shaped portion and the second comb-tooth shaped portion.
6. The image reading apparatus according to claim 1 , wherein
a value of the second capacitance is equal to parasitic capacitance between the control terminal and a terminal of the switch element, which is connected to the one end of the second capacitance.
7. A semiconductor device comprising:
a light receiving element that receives light so as to perform photoelectric conversion;
an amplifier which is electrically connected to the light receiving element, and amplifies a signal generated by photoelectric conversion;
a switch element which is electrically connected to both ends of the amplifier so as to be parallel to the amplifier;
a first capacitance which is electrically connected to both ends of the amplifier so as to be parallel to the amplifier; and
a second capacitance which has one end which is electrically connected to one end of the light receiving element and one end of the amplifier,
wherein
a second signal of which potential is changed after potential of a first signal input to a control terminal of the switch element is changed is applied to another end of the second capacitance.