| 摘要 |
The invention relates to an objective (4) and to a method for designing said objective (4) for a dental camera (1), the objective (4) comprising at least two lenses (9, 10, 20, 21) and the dental camera (1) comprising a light source (3) and an image sensor (7). An illuminating beam emitted by the light source (3) is focused by the objective (4), imaged on an object (8) to be measured, and reflected by the object (8) to be measured to form a monitoring beam (12). The monitoring beam (12) passes through the objective (4) and is directed toward the image sensor (7), the illuminating beam (11) being partially reflected by surfaces (9′, 9′, 9″, 10′, 10″, 20′, 20″, 21′, 21″) of the lenses (9, 10, 20, 21) to form reflected beams (17.1 to 17.8). The objective (4) comprises means (27) for tilting each lens (9, 10, 20, 21) relatively to the illuminating beam (11) such that the optical axis (9′″ 10′″, 15.1, 15.2) of each lens (9, 10, 20, 21) forms an angle of tilt (α,β) with the illuminating beam (11), the size of said angle being such that the reflected beams (17.1 to 17.8) can be reflected in a direction away from the pupil of the monitoring beam (12). |
| 主权项 |
1. An objective for use in a dental camera that includes a light source, an image sensor, and a telecentric diaphragm, the objective comprising:
at least two lenses including a first lens and a second lens; and a holding unit arranged to hold the at least two lenses such that: (i) an illuminating beam received on a light source side of the objective is guided by the at least two lenses and emanated from an object side of the objective, and (ii) a monitoring beam, formed by a reflection of the illuminating beam from an object to be measured and received from the object side of the objective, is guided by the at least two lenses and emanated from the light source side of the objective towards an aperture of a telecentric diaphragm and onto the image sensor, wherein the holding unit is arranged to hold the first lens such that an optical axis of the first lens forms a first angle of tilt with respect to the illuminating beam so that a reflected beam from a concave light source side surface of the first lens is reflected in a direction extending away from the aperture of the telecentric diaphragm, and wherein the holding unit is arranged to hold the second lens of the at least two lenses such that an optical axis of the second lens forms a second angle of tilt with respect to the illuminating beam to correct for aberrations caused by the tilt of the first lens at the first angle. |
