Patent ID: 8514198

Claim:
An electro-optical device comprising: a screen on which an image is displayed; a first substrate and a second substrate that are provided opposite to each other; liquid crystal that is sandwiched between the first substrate and the second substrate; an electrostatic capacity detecting section that outputs a detection signal whose level corresponds to the value of a capacitance that is formed by the liquid crystal, a first electrode, and a second electrode, wherein both of the first electrode and the second electrode are provided on a surface of the first substrate that faces the second substrate; an image displaying section that includes the liquid crystal, a third electrode, and a fourth electrode, the image displaying section controlling the transmission factor of the liquid crystal for displaying an image on the screen; a driving section that supplies an electric potential to the third electrode and supplies an electric potential to the fourth electrode so as to control the state of alignment of the liquid crystal, the driving section switching over the driving state of the liquid crystal at a predetermined cycle between a first driving state in which a first fixed potential is applied to the third electrode whereas a data potential that is in accordance with gradation to be displayed is applied to the fourth electrode and a second driving state in which a second fixed potential is applied to the third electrode whereas the data potential is applied to the fourth electrode; a first memorizing section that memorizes the level of the detection signal outputted by the electrostatic capacity detecting section in a state in which a detection target object is not in contact with the screen as reference data; a second memorizing section that memorizes the level of the detection signal outputted by the electrostatic capacity detecting section in a state in which a judgment is made as to whether the screen is contacted or not as detection target data; a controlling section that controls the operation of writing into the first memorizing section and the second memorizing section and the operation of reading out of the first memorizing section and the second memorizing section so as to ensure that the driving state of the liquid crystal corresponding to the reference data that is read out of the first memorizing section should be the same as the driving state of the liquid crystal corresponding to the detection target data that is read out of the second memorizing section; a difference data generating section that generates a difference between the reference data that has been read out of the first memorizing section and the detection target data that has been read out of the second memorizing section as difference data; and a judging section that judges whether the detection target object is in contact with the screen or not on the basis of the difference data.