Inspection apparatus and inspection method for detecting anomalies of optical elements of an additive manufacturing device

An inspection apparatus for examining an optical element with respect to an anomaly of the optical element, for use in an additive manufacturing device for producing a three-dimensional workpiece by irradiating raw material powder layers applied within an irradiation plane with a processing beam emitted by an irradiation system, wherein the optical element is arranged along an optical beam path formed by the irradiation system, between an irradiation source of the irradiation system and the irradiation plane, wherein the inspection apparatus has an illumination device, a sensing device and a control unit, wherein

• the illumination device has at least one illumination source, which is configured such that it emits illumination beams that generate at least one illumination pattern on the optical element, wherein
• the sensing device is configured such that it senses a reflected beam which comprises at least a part of the illumination beams that is reflected by the optical element, wherein
• the control unit is configured such that the illumination pattern on the optical element can be specified by the control unit, and wherein
• the control unit is configured such that it temporarily stores sensing data which comprise data from the sensing device,
• wherein
• the control unit is further configured such that the sensing data are recorded during illumination of the optical element with mutually different illumination patterns on an optical surface of the optical element, so that the anomaly of the optical element can be represented as an optical anomaly feature in the sensing data.

An inspection method for examining an optical element with respect to an anomaly of the optical element, for use in an additive manufacturing device for producing a three-dimensional workpiece by irradiating raw material powder layers applied within an irradiation plane with a processing beam emitted by an irradiation system, wherein the optical element is arranged along an optical beam path formed by the irradiation system, between an irradiation source of the irradiation system and the irradiation plane, wherein the inspection method comprises the following steps:

• i) illuminating the optical element in order to generate an illumination pattern on the optical surface of the optical element, wherein, at the same time as the illumination step,
• ii) a reflected beam is sensed, said reflected beam comprising at least a part of the illumination beams that is reflected by the optical element, wherein
• iii) the illumination pattern on the optical element can be predefined, and wherein
• iv) sensing data which comprise data from the sensing device are temporarily stored,
• wherein
• the sensing data are recorded during illumination of the optical element with mutually different illumination patterns on an optical surface of the optical element, so that the anomaly of the optical element can be represented as an optical anomaly feature in the sensing data.

An additive manufacturing device for producing a three-dimensional workpiece by irradiating raw material powder layers applied within an irradiation plane with a processing beam emitted by an irradiation system, the device comprising an inspection apparatus for examining an optical element with respect to an anomaly of the optical element, wherein the optical element is arranged along an optical beam path formed by the irradiation system, between an irradiation source of the irradiation system and the irradiation plane, wherein the inspection apparatus has an illumination device, a sensing device and a control unit, wherein

• the illumination device has at least one illumination source, which is configured such that it emits illumination beams that generate at least one illumination pattern on the optical element, wherein
• the sensing device is configured such that it senses a reflected beam which comprises at least a part of the illumination beams that is reflected by the optical element, wherein
• the control unit is configured such that the illumination pattern on the optical element can be specified by the control unit, and wherein
• the control unit is configured such that it temporarily stores sensing data which comprise data from the sensing device,
• wherein
• the control unit is further configured such that the sensing data are recorded during illumination of the optical element with mutually different illumination patterns on an optical surface of the optical element, so that the anomaly of the optical element can be represented as an optical anomaly feature in the sensing data.