Abstract: A multi-beam apparatus for inspecting or processing a sample with a multitude of focused beams uses a multitude of detectors for detecting secondary radiation emitted by the sample when is irradiated by the multitude of beams. Each detector signal comprises information caused by multiple beams, the apparatus equipped with a programmable controller for processing the multitude of detector signals to a multitude of output signals, using weight factors so that each output signal represents information caused by a single beam. The weight factors are dynamic weight factors depending on the scan position of the beams with respect to the detectors and the distance between sample and detectors.

Abstract: The height of a surface (25) along an axis (4) is determined by measuring the axial position of an irradiated spot (31) formed on the surface at the intersection of the surface and the axis. Radiation reflected by the surface and collected by a lens (8) forms an image spot (32) on the axis (4). The position of the image spot is determined by measuring the intensity of the radiation at at least three positions along the axis by means of a detection unit (35). The output signals (44, 44') of the detection unit are processed in an electronic means (43) for determining the position of the highest radiation intensity and for supplying a signal (43') whose magnitude represents the axial position of the image spot (32), hence, of the irradiated spot (31 ).

Abstract: Method of positioning an object on a carrier, device suitable for carrying out this method, and suction tube suitable for use in the device.The method is for laser soldering of an electronic component (7) on a pc-board (1). The component is positioned on a contact face (3) of the pc-board (1) by a device comprising a vibration transducer (53, 69, 85) which is brought into mechanical hard contact with the component (7) while the component is held against the pc-board. Subsequently, a laser (205, 207) heats solder present on the contact face and vibrations generated by the laser in the solder are passed on to the vibration transducer while the mechanical hard contact is being maintained. The vibration transducer then checks for the presence of mechanical contact between the object and the carrier and/or the melting of the solder from a comparatively strong decrease in the vibration amplitude during melting of the solder.

Abstract: Methods, devices and an image sensor for investigating an object (13) by means of a reflectable radiation beam (25) which forms a spot (24) on the object which can be moved relative to the object (13), whereby the actual position of the spot on the object is determined by means of the reflected portion of the radiation beam detected by an optical detector (23), while the desired position of the spot relative to the object is determined by means of a multidimensional image sensor (21). The radiation beam can subsequently be moved relative to the object until the actual position of the spot corresponds to the desired position of the spot, or differences between the actual and the desired position of the spot may be determined as a measure for differences in the distance between the object and a reference plane (62).

Abstract: A measuring device comprises at least two transducer units for sensing input quantities (A.sub.i) and for producing signals which are proportional to the logarithm of the input quantities. The measuring device also includes a normalization circuit which determines the ratio of a linear combination of input quantities to the sum of the input quantities. The normalization circuit thus comprises a number of first identical bipolar transistors which correspond to the number of input quantities. The transistors include a base, an emitter and a collector. An output signal of a transducer unit is applied to the base of the corresponding first transistor. The emitters of these transistors are collectively connected to a constant current source via an emitter junction.

Abstract: A measuring device comprises a detector (1) for a quantity x to be measured, which detector is adapted to produce two signals I.sub.1 and I.sub.2 which relate to x as x=(I.sub.1 -I.sub.2)/(I.sub.1 +I.sub.2). The device further comprises a processing circuit (3) which includes a first and a second logarithmic converter (9, 11) whose inputs receive input signals V.sub.1 and V.sub.2 which are proportional to the first and the second measuring signal I.sub.1, I.sub.2, respectively. The outputs of the logarithmic converters are connected to first and second inputs (12A, 12B) of a subtractor circuit (13) which produces at its output (14) an output signal U(x) which depends on the quantity x to be measured. If a subtractor circuit is used which is adapted to determine the hyperbolic tangent of the difference between the signals logV.sub.1 and logV.sub.2 present at its two inputs (12A, 12B), the relationship between u(x) and x will be linear.