Observation apparatus, optical deflection unit, and image formation method

1. An observation apparatus comprising:

a case including a transmissive window;

an image sensor housed in the case;

an optical system housed in the case, the optical system being configured to condense light incident inside the case by transmitting through the transmissive window to form an image of a sample inside a container placed on the transmissive window above the image sensor;

a light source housed in the case, the light source being configured to emit light to an outside of the case without passing through the optical system; and

an optical deflection unit having a surface configured to deflect light emitted from the light source to an outside of the case in a first direction going toward the transmissive window, such that an angle of exit defined as the angle between the first direction and an optical axis of the optical system is different from an angle of incidence defined as the angle between a second direction in which light emitted to the outside of the case is incident on the optical deflection unit, and the optical axis.

2. The observation apparatus according to claim 1 , wherein a pencil of light containing light deflected in the first direction by the optical deflection unit and passing through a point on the sample is distributed straddling an outer edge of a pupil of the optical system in a pupil plane of the optical system.

3. The observation apparatus according to claim 2 , wherein the angle of exit is larger than the angle of incidence.

4. The observation apparatus according to claim 2 , wherein the angle of exit is smaller than the angle of incidence.

5. The observation apparatus according to claim 1 , wherein the angle of exit is larger than the angle of incidence.

6. The observation apparatus according to claim 1 , wherein the angle of exit is smaller than the angle of incidence.

7. The observation apparatus according to claim 1 , wherein the surface of the optical deflection unit comprises at least one reflective surface configured to reflect light incident on the optical deflection unit.

8. The observation apparatus according to claim 7 , wherein the at least one reflective surface includes a reflective surface inclined with respect to the optical axis.

9. The observation apparatus according to claim 8 , wherein the reflective surface inclined with respect to the optical axis includes a metal thin-film mirror or a dielectric multilayer film mirror formed on a surface of a base material.

10. The observation apparatus according to claim 9 , wherein the at least one reflective surface includes a plurality of inclined faces arranged in a direction intersecting the optical axis.

11. The observation apparatus according to claim 8 , wherein the at least one reflective surface includes a plurality of inclined faces arranged in a direction intersecting the optical axis.

12. The observation apparatus according to claim 11 , wherein the at least one reflective surface is a partially reflective mirror or a splitter configured to reflect a portion of incident light and transmit the rest.

13. The observation apparatus according to claim 7 , wherein the optical deflection unit further includes an adjustment unit configured to adjust the angle of the at least one reflective surface with respect to the optical axis.

14. The observation apparatus according to claim 13 , wherein

the optical deflection unit further includes a prism plate having a plurality of refractive surfaces arranged in a direction intersecting the optical axis,

each of the plurality of refractive surfaces

is a refractive surface inclined with respect to the optical axis that refracts light incident on the optical deflection unit, and

is provided on an optical path between the at least one reflective surface and the transmissive window.

15. The observation apparatus according to claim 7 , wherein

the optical deflection unit further includes at least one refractive surface configured to refract light incident on the optical deflection unit, and

the at least one refractive surface is provided on an optical path between the at least one reflective surface and the transmissive window.

16. The observation apparatus according to claim 7 , wherein

the optical deflection unit further includes a prism plate having a plurality of refractive surfaces arranged in a direction intersecting the optical axis,

each of the plurality of refractive surfaces

is a refractive surface inclined with respect to the optical axis that refracts light incident on the optical deflection unit, and

is provided on an optical path between the at least one reflective surface and the transmissive window.

17. The observation apparatus according to claim 16 , wherein the at least one reflective surface is a partially reflective mirror or a splitter configured to reflect a portion of incident light and transmit the rest.

18. The observation apparatus according to claim 1 , wherein

the optical deflection unit further includes a first face that does not face opposite the transmissive window, and

at least a portion of the first face is a plane parallel to the transmissive window.

19. An image formation method comprising:

emitting light from an inside of a case to an outside of the case;

deflecting, with a surface of an optical deflection unit, the light emitted to the outside of the case to a first direction proceeding toward a transmissive window of the case; and

condensing, with an optical system inside the case, light incident inside the case by transmitting through the transmissive window to form an image of a sample inside a container placed on the transmissive window above an image sensor, wherein

an angle of exit defined as the angle between the first direction and an optical axis of the optical system is different from an angle of incidence defined as the angle between a second direction in which light emitted to the outside of the case is incident on the optical deflection unit, and the optical axis.