Abstract: An intraoral camera including a main body case, an intraoral insertion component mounted on the front side of the main body case, an imaging window provided to the intraoral insertion component, and an imaging device that is optically linked to the imaging window and is disposed inside the main body case or inside the intraoral insertion component. Illumination elements are disposed at portions of an outer peripheral wall face that are substantially opposite each other in the horizontal direction. These illumination elements are inclined toward the outside of the imaging window in the center of the imaging window, and the outer peripheral wall face that is substantially opposite these illumination elements in the vertical direction is constituted as a light collecting face that is inclined toward the outside of the imaging window in the center of the imaging window.

Abstract: The intraoral camera of the present invention comprises a main body case (1), an intraoral insertion component (3) mounted on the front side of the main body case (1), an imaging window (3a) provided to the intraoral insertion component (3), and an imaging device (10) that is optically linked to the imaging window (3a) and is disposed inside the main body case (1) or inside the intraoral insertion component (3). Illumination elements (9) are disposed at portions of an outer peripheral wall face (17) that are substantially opposite each other in the horizontal direction. These illumination elements (9) are inclined toward the outside of the imaging window in the center of the imaging window (3a), and the outer peripheral wall face (17) that is substantially opposite these illumination elements (9) in the vertical direction is constituted as a light collecting face that is inclined toward the outside of the imaging window in the center of the imaging window (3a).

Abstract: To provide a compact and low-cost projector lens capable of appropriately performing temperature correction and obtaining excellent image quality although using a plurality of plastic lens elements, a first lens unit having negative refractive power and a second lens unit having positive refractive power are provided from the screen side, the first lens unit includes a negative meniscus lens element 1b being a plastic lens element, being convex to the screen side and having an aspherical surface, the second lens unit includes: a negative lens element 2b being a plastic lens element and having an aspherical surface; and at least two positive lens elements having anomalous dispersibility and a temperature coefficient of a negative refractive index, and an image plane fluctuation by a temperature change due to a temperature coefficient of a negative refractive index of the plastic lens elements 1b and 2b of the first and second lens units is corrected by the temperature coefficient of the predetermined negative

Abstract: To provide a compact and low-cost projector lens capable of appropriately performing temperature correction and obtaining excellent image quality although using a plurality of plastic lens elements, a first lens unit having negative refractive power and a second lens unit having positive refractive power are provided from the screen side, the first lens unit includes a negative meniscus lens element 1b being a plastic lens element, being convex to the screen side and having an aspherical surface, the second lens unit includes: a negative lens element 2b being a plastic lens element and having an aspherical surface; and at least two positive lens elements having anomalous dispersibility and a temperature coefficient of a negative refractive index, and an image plane fluctuation by a temperature change due to a temperature coefficient of a negative refractive index of the plastic lens elements 1b and 2b of the first and second lens units is corrected by the temperature coefficient of the predetermined negative

Abstract: A zoom lens system with temperature compensation function includes the first lens group having a positive refractive power, the second lens group that has negative refractive power and moves along an optical axis, the third lens group having a plastic lens of positive refractive power, the fourth lens group that has positive refractive power and moves along the optical axis, the first lens barrel which extends from the first lens group to the third lens group, and the second lens barrel which extends from the third lens group to an image pickup element, and expansion or contraction of at least one of lens barrels in accordance with temperature change cancels variation of image location caused by temperature change of the lens groups.

Abstract: A zoom lens includes a first lens group (1) having a positive refracting force that is fixed, a second lens group (2) having a negative refracting force that is movable along an optical axis and provided with a function of varying magnification, a third lens group (3) having a positive refracting force that is fixed, and a fourth lens group (4) having a positive refracting force that is movable along an optical axis and provided with a function of correcting fluctuations of an image plane resulting from varying magnification or changing an object distance (4), the first, second, third and fourth lens groups being disposed from an object side in this order, wherein the third lens group (3) and the fourth lens group (4) both include a positive glass spherical lens (L5, L8) and a plastic aspherical lens (L6, L7) having weaker refracting power. Thus, a compact zoom lens having a high magnification ratio of 20 times can be obtained at low cost.

Abstract: A zoom lens system with temperature compensation function includes the first lens group having a positive refractive power, the second lens group that has negative refractive power and moves along an optical axis, the third lens group having a plastic lens of positive refractive power, the fourth lens group that has positive refractive power and moves along the optical axis, the first lens barrel which extends from the first lens group to the third lens group, and the second lens barrel which extends from the third lens group to an image pickup element, and expansion or contraction of at least one of lens barrels in accordance with temperature change cancels variation of image location caused by temperature change of the lens groups.

Abstract: A zoom lens includes a first lens group (1) having a positive refracting force that is fixed, a second lens group (2) having a negative refracting force that is movable along an optical axis and provided with a function of varying magnification, a third lens group (3) having a positive refracting force that is fixed, and a fourth lens group (4) having a positive refracting force that is movable along an optical axis and provided with a function of correcting fluctuations of an image plane resulting from varying magnification or changing an object distance (4), the first, second, third and fourth lens groups being disposed from an object side in this order, wherein the third lens group (3) and the fourth lens group (4) both include a positive glass spherical lens (L5, L8) and a plastic aspherical lens (L6, L7) having weaker refracting power. Thus, a compact zoom lens having a high magnification ratio of 20 times can be obtained at low cost.