Concentrating lens, photodetector with concentrating lens, concentrating lens unit

A concentrating lens that concentrates light incident along an optical axis direction and emits the light, the lens comprising:

• an incident surface that is a surface on a first side in the optical axis direction;
• and
• an emitting surface and a reflective surface that are surfaces on a second side in the optical axis direction,
• wherein the incident surface includes a central portion and an outer portion surrounding the central portion when viewed in the optical axis direction,
• the incident surface is formed by an inner surface of a depression portion recessed toward a center of the central portion,
• the reflective surface surrounds the emitting surface when viewed in the optical axis direction,
• the reflective surface extends so as to go toward the first side as going toward an outside,
• a first light incident on the outer portion of the incident surface transmits through the outer portion, is reflected by the reflective surface, reflected by the incident surface, and incident on the emitting surface,
• a second light incident on the central portion of the incident surface transmits through the central portion and is incident on the emitting surface,
• the central portion reflects the first light reflected by the reflective surface, toward the emitting surface and transmits the second light, and
• wherein when a region on the incident surface is defined as a non-effective region, light incident on the region in parallel to the optical axis direction not being incident on the emitting surface, the non-effective region is set on the incident surface such that a concentration efficiency of the concentrating lens for the light parallel to the optical axis direction is 50% or more.

A concentrating lens that concentrates light incident along an optical axis direction and emits the light, the lens comprising:

• an incident surface that is a surface on a first side in the optical axis direction;
• and
• an emitting surface and a reflective surface that are surfaces on a second side in the optical axis direction,
• wherein the incident surface includes a central portion and an outer portion surrounding the central portion when viewed in the optical axis direction,
• the incident surface is formed by an inner surface of a depression portion recessed toward a center of the central portion,
• the reflective surface surrounds the emitting surface when viewed in the optical axis direction,
• the reflective surface extends so as to go toward the first side as going toward an outside,
• a first light incident on the outer portion of the incident surface transmits through the outer portion, is reflected by the reflective surface, reflected by the incident surface, and incident on the emitting surface,
• a second light incident on the central portion of the incident surface transmits through the central portion and is incident on the emitting surface,
• the central portion reflects the first light reflected by the reflective surface, toward the emitting surface and transmits the second light, and
• when a region on the incident surface is defined as a non-effective region, light incident on the region in parallel to the optical axis direction not being incident on the emitting surface, the non-effective region is set on the incident surface such that an area of the non-effective region is 50% or less of an entire area of the incident surface.

A concentrating lens that concentrates light incident along an optical axis direction and emits the light, the lens comprising:

• an incident surface that is a surface on a first side in the optical axis direction;
• and
• an emitting surface and a reflective surface that are surfaces on a second side in the optical axis direction,
• wherein the incident surface includes a central portion and an outer portion surrounding the central portion when viewed in the optical axis direction,
• the incident surface is formed by an inner surface of a depression portion recessed toward a center of the central portion,
• the reflective surface surrounds the emitting surface when viewed in the optical axis direction,
• the reflective surface extends so as to go toward the first side as going toward an outside,
• a first light incident on the outer portion of the incident surface transmits through the outer portion, is reflected by the reflective surface, reflected by the incident surface, and incident on the emitting surface,
• a second light incident on the central portion of the incident surface transmits through the central portion and is incident on the emitting surface,
• the central portion reflects the first light reflected by the reflective surface, toward the emitting surface and transmits the second light, and
• when a region on the incident surface is defined as a non-effective region, light incident on the region in parallel to the optical axis direction not being incident on the emitting surface, the incident surface does not include the non-effective region.