Biosensor having light emitting and receiving elements to obtain a biological signal
A biosensor includes light emitting elements and a light receiving element disposed on a principal surface of a wiring board; a light shielding portion disposed between a light-emitting-element sealing portion and a light-receiving-element sealing portion; a base medium having light transmitting properties, disposed in parallel with the wiring board with the light shielding portion therebetween; an adhesion layer having light transmitting properties, configured to bond the base medium with the light-emitting-element sealing portion, the light-receiving-element sealing portion, and the light shielding portion; and a first electrocardiograph electrode attached to a principal surface of the base medium. The refractive index of the base medium is set to be higher than that of the adhesion layer, and a surface of the first electrocardiograph electrode which is adjacent to the base medium is roughened so that stray light passing through the base medium will be scattered.
1. A biosensor comprising:
a wiring board;
a light emitting element and a light receiving element disposed on a principal surface of the wiring board;
a light-emitting-element sealer disposed on the principal surface of the wiring board and adjacent to the light emitting element to seal the light emitting element;
a light-receiving-element sealer disposed on the principal surface of the wiring board and adjacent to the light receiving element to seal the light receiving element;
a light shielding portion disposed between the light-emitting-element sealer and the light-receiving-element sealer;
a base medium with light transmitting properties disposed in parallel with the wiring board with the light shielding portion therebetween;
an adhesion layer with light transmitting properties disposed between the base medium and at least one of the light shielding portion, the light-emitting-element sealer, and the light-receiving-element sealer, the adhesion layer provided to bond the base medium with the at least one of the light shielding portion, the light-emitting-element sealer, and the light-receiving-element sealer; and
a plane electrode disposed on a principal surface of the base medium such that the plane electrode does not overlap the light emitting element and the light receiving element when viewed from a direction normal to the principal surface of the wiring board, wherein the plane electrode is configured to monitor a potential of a body.
2. The biosensor according to claim 1 , wherein a refractive index of the adhesion layer is higher than a refractive index of the base medium, and the light shielding portion comprises a roughened surface to scatter light passing through the adhesion layer.
3. The biosensor according to claim 1 , wherein the adhesion layer is at least partially divided with a first portion adjacent to the light emitting element and a second portion adjacent to the light receiving element.
4. The biosensor according to claim 3 , wherein the adhesion layer is divided such that an angle between a direction in which the adhesion layer is divided and a direction parallel with a straight line connecting the light emitting element and the light receiving element in a plane parallel to the principal surface of the wiring board is less than or equal to 50°.
5. The biosensor according to claim 3 , wherein the adhesion layer is fully divided into the first portion adjacent to the light emitting element and the second portion adjacent to the light receiving element.
6. The biosensor according to claim 1 , wherein the light transmitting properties of the adhesion layer have a lower light transmittance than the light transmitting properties of the base medium.
7. The biosensor according to claim 6 , wherein the adhesion layer comprises a double-sided tape that includes a strip-like core member made of paper or nonwoven fabric and adhesive layers formed on both sides of the core member.
8. The biosensor according to claim 1 , wherein the light emitting element comprises a pair of light emitting devices configured to emit light beams at different wavelengths.
9. The biosensor according to claim 1 , wherein the light-emitting-element sealer and the light-receiving-element sealer each comprise a circular truncated cone shape that surrounds the light emitting element and the light receiving element, respectively.
10. A biosensor comprising:
a wiring board;
a light emitting element and a light receiving element disposed on a principal surface of the wiring board;
a light-emitting-element sealer disposed on the principal surface of the wiring board and adjacent to the light emitting element to seal the light emitting element;
a light-receiving-element sealer disposed on the principal surface of the wiring board and adjacent to the light receiving element to seal the light receiving element;
a light shielding portion disposed between the light-emitting-element sealer and the light-receiving-element sealer;
a base medium with light transmitting properties disposed in parallel with the wiring board with the light shielding portion therebetween;
an adhesion layer with light transmitting properties disposed between the base medium and at least one of the light shielding portion, the light-emitting-element sealer, and the light-receiving-element sealer, the adhesion layer provided to bond the base medium with the at least one of the light shielding portion, the light-emitting-element sealer, and the light-receiving-element sealer; and
a plane electrode disposed on the base medium and configured to monitor a potential of a body,
wherein a refractive index of the base medium is higher than a refractive index of the adhesion layer, and the plane electrode comprises a roughened surface to scatter light passing through the base medium.