Optical biological information detecting apparatus and optical biological information detecting method
An optical biological information detecting apparatus includes a light emitting unit which emits observation light of a specific wavelength band to optically observe a desired portion of a tissue of a skin of a human body, and an annular light guide unit which guides the observation light to a desired area of a surface of the skin corresponding to the desired portion of the tissue of the skin, and which annularly irradiates the observation light onto the desired area of the surface of the skin. The apparatus further includes a light receiving unit which is disposed at a position surrounded by the annular light guide unit, and which receives scattered light scattered by the desired portion of the tissue of the skin after the observation light is annularly irradiated onto the desired area of the surface of the skin by the annular light guide unit.
1. An optical biological information detecting apparatus, comprising:
a light emitting unit which emits observation light of a specific wavelength band to optically observe a desired portion of a tissue of a skin of a human body;
an annular light guide unit which is adapted to contact a desired area of a surface of the skin corresponding to the desired portion of the tissue of the skin, which guides the observation light to the desired area of the surface of the skin, and which annularly irradiates the observation light onto the desired area of the surface of the skin; and
a light receiving unit which is disposed at a position surrounded by the annular light guide unit, and which receives scattered light scattered by the desired portion of the tissue of the skin after the observation light is annularly irradiated onto the desired area of the surface of the skin by the annular light guide unit, the light receiving unit including an optical filter, a light receiving element and a holder portion which has a light shielding function and in which the light receiving element and the optical filter are disposed to adapt the optical filter to contact a position of the surface of the skin surrounded by the annular light guide unit, and the holder portion shielding light excluding the scattered light toward the optical filter.
2. The optical biological information detecting apparatus according to claim 1 , wherein
the annular light guide unit comprises:
a light guiding ring portion which comprises an outer circumferential surface and an inner circumferential surface defining a circular hole, the outer circumferential surface being provided with an incident surface on which the observation light is incident from the light emitting unit, and the inner circumferential surface being provided with an emission surface to emit the observation light incident in the incident surface; and
a diffusion/reflection ring portion which is disposed in the circular hole of the light guiding ring portion, which comprises an outer circumferential surface facing the inner circumferential surface of the circular hole and a skin surface facing surface facing the desired area of the surface of the skin, the outer circumferential surface being provided with an incident surface on which the observation light emitted from the emission surface of the light guiding ring portion is incident, the skin surface facing surface being provided with an annular emission surface to annularly diffuse the observation light incident in the incident surface and to annularly irradiate the diffused observation light onto the desired area of the surface of the skin, and which guides the observation light incident in the incident surface to the annular emission surface by reflection.
3. The optical biological information detecting apparatus according to claim 2 , wherein
each of the light guiding ring portion and the diffusion/reflection ring portion has the same predetermined height as to each other in a direction crossing the surface of the skin and are disposed in a direction along the surface of the skin without generating a step in the crossing direction, and
the light emitting unit and the light receiving unit are disposed within a range of the predetermined height.
4. The optical biological information detecting apparatus according to claim 2 , further comprising:
a diffusion/irradiation ring portion which is provided to correspond to the annular emission surface of the skin surface facing surface of the diffusion/reflection ring portion and to face the desired area of the surface of the skin, which transmits the annularly diffused observation light emitted from the annular emission surface of the diffusion/reflection ring portion, and which annularly diffuses and irradiates the annularly diffused observation light toward the desired area of the surface of the skin.
5. The optical biological information detecting apparatus according to claim 1 , wherein
the observation light emitted from the light emitting unit is a light of an infrared band of 800 nm or more which has a low absorbance to melanine pigment contained in the skin.
6. The optical biological information detecting apparatus according to claim 1 , wherein
the annular light guide unit comprises a reflection layer that reflects the observation light emitted from the light emitting unit to the desired area of the surface of the skin, and
the reflection layer prevents the scattered light until the scattered light is received by the light receiving unit after being scattered in the desired portion of the tissue of the skin from being mixed with the observation light in the light guide unit.
7. The optical biological information detecting apparatus according to claim 1 , wherein:
the optical filter transmits only light of a specific wavelength band of 800 nm or more among the scattered light toward the light receiving unit.
8. The optical biological information detecting apparatus according to claim 1 , wherein
the light receiving unit has a spectral sensitivity characteristic which reacts with only light of a specific wavelength band among the scattered light toward the light receiving unit.
9. The optical biological information detecting apparatus according to claim 1 , wherein
the optical biological information detecting apparatus is combined with a wristwatch which comprises a time piece module and a body case including an internal space to store the time piece module and a back cover,
the light emitting unit, the light guide unit, and the light receiving unit are provided in the internal space of the body case of the wristwatch, and
the back cover is provided with an observation light/scattered light transmitting structure which transmits the observation light annularly irradiated from the light guide unit to the desired area of the surface of the skin and which transmits the scattered light scattered by the desired portion of the tissue of the skin after the observation light is annularly irradiated onto the desired area of the surface of the skin by the annular light guide unit.