U.S. Philips Corporation

Robert F Van Der Ven

Jorg Brambring

A quantity of material is locally deposited on or removed from a substantially flat substrate of a circuit board. The quantity is inspected by carrying out a first measurement of a level of a surface of the material in a direction transversely of the substrate. At least two further measurements are performed of a further level of the substrate in said direction in at least two further locations where the material has not been deposited or removed. A reference level of the substrate is calculated by interpolation between the further measurements to a location of the first measurement. The quantity of material is inspected on the basis of a difference between the first measurement and the reference level.

Method of and device for inspecting a PCB

A color selection electrode (29) for a color television display tube is suspended in the corners of the display window (20) with the aid of suspension means which comprise a flat resilient element (27). The resilient element (27) comprises an embossment (28). The embossment (28) falls partly through a recess (36) in a brace (34) which is connected to the color selection electrode (29). This assembly of the embossment (28) and the recess (36) forms a so-called ball joint. As a result of the hinging action of the ball-joint the color selection electrode (29) is suspended without moments being exerted on the color selection electrode (29). FIG. 2a.

Color television display tube

A shadow mask (20) for a color display tube is formed from one piece. Each side of the shadow mask (20) comprises a bulged portion (23) with a collar (24). Having a center of mass which when viewed in a cross-section perpendicular to the side, is situated substantially in the plane of the shadow mask sheet (21). As a result of this no moments are exerted on the shadow mask (20) when vibrations and shocks occur, so that the mask is not deformed. The angle which the collars (24) make with the longitudinal axis of the display tube is such that electrons reflected at a collar (24) do not land within the pattern of apertures (22) on the shadow mask (20). A magnetic screening cap adapted to the shadow mask construction is also constructed so that electrons reflected at the cap do not land within the pattern of apertures (22) of the shadow mask (20).

Color display tube including a shadow mask sheet with a bulged portion

The haze around the electron beam spot in the corners and at the edge of the display screen is reduced by using in the electron gun a first grid of a construction such that a multipole lens which is mainly a first quadrupole lens is formed in cooperation with the cathode. The first grid in cooperation with the second grid also forms a multipole lens which is also a mainly second quadrupole lens and which is rotated 90.degree. with respect to the first quadrupole lens. Such a system of lenses in the first grid can be formed, for example, by providing in the first grid an aperture with elongated openings both on the side of the cathode and on the side of the second grid. The longitudinal axis of the elongated opening on the side of the cathode is substantially at right angles to the longitudinal axis of the elongated opening on the side of the second grid.

CRT Control grid having orthogonal openings on opposite sides

Disclosed is a color display tube having a color selection electrode comprised of a metal plate having a large number of apertures and a plurality of elongated conductors insulated from the plate which extend across the apertures and divide them into two substantially symmetrical halves. Upon application of a suitable potential difference between the conductors and the plate, electric fields are produced in the apertures which deflect the portions of the beam passing through the respective aperture halves towards each other forming on the display screen a single, overlapping electron spot of a width smaller than that of the aperture.

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Eindhoven, Netherlands

Robert F Van Der Ven