Biological signal acquisition device and method for acquiring biological signal

1. A biological signal acquisition device comprising:

an electrode made up of a plurality of cell electrodes, and comes into contact with a biological body; and

a controller that acquires an electrical signal from the biological body through a pair of cell electrode groups made up of a part or all of the plurality of cell electrodes,

wherein the controller

determines a contact condition between the part or all of the plurality of cell electrodes and the biological body, based on a detection signal acquired by scanning the part or all of the plurality of cell electrodes, and

selects the cell electrodes making up the pair of cell electrode groups, based on the determined contact condition so that contact resistances between the cell electrode groups and the biological body are equal between the pair of cell electrode groups.

2. The biological signal acquisition device according to claim 1 , wherein the controller determines the contact condition, based on a signal intensity of the detection signal.

3. The biological signal acquisition device according to claim 1 , wherein the controller selects the cell electrodes making up the pair of cell electrode groups from the cell electrodes determined to be in contact with the biological body, based on the detection signal.

4. The biological signal acquisition device according to claim 3 , wherein the controller selects the cell electrodes making up the pair of cell electrode groups so that a sum of a contact area between the cell electrodes making up one of the pair of the cell electrode groups, and the biological body is equal to a sum of a contact area between the cell electrodes making up the other of the pair of the cell electrode groups, and the biological body.

5. The biological signal acquisition device according to claim 3 , wherein the controller selects the cell electrodes making up the pair of cell electrode groups so that numbers of the cell electrodes making up the respective cell electrode groups are equal between the pair of cell electrode groups.

6. The biological signal acquisition device according to claim 1 , wherein the controller selects the cell electrodes making up the pair of cell electrode groups from the cell electrodes determined to be in contact with the biological body, based on the detection signal.

7. The biological signal acquisition device according to claim 6 , wherein the controller selects the cell electrodes making up the pair of cell electrode groups so that a sum of a contact area between the cell electrodes making up one of the pair of the cell electrode groups, and the biological body is equal to a sum of a contact area between the cell electrodes making up the other of the pair of the cell electrode groups, and the biological body.

8. The biological signal acquisition device according to claim 6 , wherein the controller selects the cell electrodes making up the pair of cell electrode groups so that numbers of the cell electrodes making up the respective cell electrode groups are equal between the pair of cell electrode groups.

9. The biological signal acquisition device according to claim 1 , wherein

the controller selects a pair of candidate groups made up of a part or all of the plurality of cell electrodes,

one or more of the cell electrodes in at least one of the pair of candidate groups are opened so that contact resistances between the cell electrodes and the biological body are equal between the pair of candidate groups, and

at least one of the pair of cell electrode groups is made up of the cell electrodes not opened in the candidate group.

10. The biological signal acquisition device according to claim 1 , wherein the controller obtains an electrocardiographic waveform based on the electrical signal.

11. The biological signal acquisition device according to claim 1 , wherein

the controller selects a pair of candidate groups made up of a part or all of the cell electrodes making up the electrode, based on a differential signal intensity between the candidate groups, and

selects the cell electrodes making up the cell electrode groups corresponding to the respective candidate groups from the cell electrodes making up the respective candidate groups.

12. The biological signal acquisition device according to claim 1 , wherein when the contact condition between any of the cell electrodes and the biological body changes, the controller again acquires the detection signal from the cell electrode, the contact condition of which has been changed, by again scanning the relevant cell electrode.

13. A method for acquiring a biological signal in which an electrode made up of a plurality of cell electrodes is brought into contact with a biological body to acquire an electrical signal from the biological body, the method comprising:

acquiring a detection signal by scanning a part or all of the plurality of cell electrodes;

determining a contact condition between the part or all of the plurality of cell electrodes and the biological body, based on the detection signal;

deciding a pair of cell electrode groups from the plurality of cell electrodes, based on the determined contact condition;

selecting the cell electrodes making up the pair of cell electrode groups so that contact resistances between the cell electrode groups and the biological body are equal between the pair of cell electrode groups in the decision of the pair of cell electrode groups; and

acquiring the electrical signal from the pair of cell electrode groups.