Illumination optical system for endoscope, optical adapter for endoscope, and optical element
A light transmission optical member for endoscope includes an incident surface provided at a distal end portion of an insertion section, light being made incident on the incident surface as incident light from a proximal end side of the insertion section, and an emission surface for emitting the light as illumination light. The emission surface includes a diffusing section that diffuses the emitted light. The diffusing section includes a plurality of convex-shaped sections extending in a predetermined direction on the emission surface. Each of the convex-shaped sections includes a first slope section having a first angle with respect to the emission surface, and totally reflecting the incident light, and a second slope section having a second angle smaller than the first angle with respect to the emission surface, and transmitting and emitting reflected light totally reflected on the first slope section and the incident light.
1. An illumination optical system configured for use with an endoscope, the illumination optical system comprising:
an optical element comprising:
an incident surface configured to connect to a distal end portion of an insertion section of the endoscope, light from the distal end of the insertion section being made incident on the incident surface as incident light, and
an emission surface for emitting the light as illumination light,
wherein the emission surface includes a diffusing section that diffuses the emitted light,
the diffusing section includes a plurality of convex-shaped sections extending in a predetermined direction on the emission surface, and
each of the convex-shaped sections comprising:
a total reflection surface having a first angle with respect to the emission surface, the total reflection surface totally reflecting the incident light, and
a transmission surface having a second angle smaller than the first angle with respect to the emission surface, the transmission surface transmitting and emitting reflected light totally reflected on the total reflection surface and the incident light.
2. The illumination optical system according to claim 1 , wherein each of the convex-shaped sections includes two convex sections, each of which is formed by the total reflection surface and the transmission surface to be plane symmetrical with respect to a surface orthogonal to the emission surface and parallel to the predetermined direction.
3. The illumination optical system according to claim 1 , wherein when viewed in the predetermined direction, the first angle is equal to or larger than 60° and equal to or smaller than 85° with respect to the emission surface and the second angle is larger than 0° and equal to or smaller than 30° with respect to the emission surface.
4. The illumination optical system according to claim 2 , wherein a depth of a first groove formed by two adjacent total reflection surfaces is larger than a depth of a second groove formed by two adjacent transmission surfaces.
5. The illumination optical system according to claim 1 , wherein a part of the plurality of convex-shaped sections is disposed in a same plane as another part of the plurality of convex-shaped sections, and the plane has a dimension that extends in a same direction as the predetermined direction.
6. The illumination optical system according to claim 1 , wherein a plurality of regions are provided where a part of the plurality of convex-shaped sections is disposed on a same plane as another part of the plurality of convex-shaped sections, and the plane has a dimension that extends in a same direction as the predetermined direction.
7. The illumination optical system according to claim 1 , wherein the illumination optical system for endoscope is an illumination optical system for an endoscope for front view, perspective view, or side view.
8. The illumination optical system according to claim 7 , wherein when the illumination optical system is for a front view, the optical element is a rod lens.
9. The illumination optical system according to claim 7 , wherein when the illumination optical system is for a side view, the optical element is a prism having one of a substantial U shape or a shape of a part of the substantial U shape, the prism including two reflection surfaces for reflecting the incident light.
10. The illumination optical system according to claim 1 , further comprising:
a first optical member provided on a side of the emission surface of the optical element and including a sand grain surface on an opposite side of the side of the emission surface; and
a second optical member bonded to the first optical member by an adhesive on the sand grain surface.
11. An optical adapter configured for use with an endoscope, the optical adapter comprising:
an optical element comprising:
an incident surface configured to connect to a distal end portion of an insertion section of the endoscope, light from the distal end of the insertion section being made incident on the incident surface as incident light, and
an emission surface for emitting the light as illumination light; and
an illumination window for emitting the illumination light emitted from the emission surface of the optical element,
wherein the emission surface includes a diffusing section that diffuses the emitted light,
the diffusing section includes a plurality of convex-shaped sections extending in a predetermined direction on the emission surface, and
each of the convex-shaped sections comprising:
a total reflection surface having a first angle with respect to the emission surface, the total reflection surface totally reflecting the incident light, and
a transmission surface having a second angle smaller than the first angle with respect to the emission surface, the transmission surface transmitting and emitting reflected light totally reflected on the total reflection surface and the incident light.
12. The optical adapter according to claim 11 , wherein the optical adapter for endoscope emits the illumination light from the illumination window in a direction orthogonal to a longitudinal axial direction of the optical adapter or at an angle intersecting the longitudinal axial direction.
13. The optical adapter according to claim 11 , wherein the optical adapter for endoscope emits the illumination light from the illumination window to a front of the distal end portion in a longitudinal axial direction of the optical adapter.
14. An optical element comprising:
an incident surface on which light is made incident as incident light; and
an emission surface for emitting the light as emitted light,
wherein the emission surface includes a diffusing section that diffuses the emitted light,
the diffusing section includes a plurality of convex-shaped sections extending in a predetermined direction on the emission surface, and
each of the convex-shaped sections comprising:
a total reflection surface having a first angle with respect to the emission surface, the total reflection surface totally reflecting the incident light, and
a transmission surface having a second angle smaller than the first angle with respect to the emission surface, the transmission surface transmitting and emitting reflected light totally reflected on the total reflection surface and the incident light.