Protocad, Inc.

Hewlett-packard Company

Ronald G Reed

Robert K McCullough

Robin R Schmuckal

John T Rasper

Michael Gustafson

A process of forming plated through-holes in a printed circuit board involves placing a film of fluid ink having electrically conductive properties on a side wall of the hole, curing the film to a solid and electroplating a layer of metal on the conductive ink film. The conductive ink preferably is a composition including conductive particles such as carbon and silver flakes. The ink also preferably includes a thermosetting or radiation curable binder and a thinner. The film of ink is cured before the layer of metal is electroplated thereon. The plated through-hole is protected from the etchant when the conductors are etched by placing a radiation curable putty material into the hole, curing it, and then depositing a layer of resist on top of the cured putty and a conductive sheet clad to the substrate of the circuit board.

Printed circuit board through hole technique

A process of forming plates through-holes in a printed circuit board involves placing a film of fluid ink having electrically conductive properties on a side wall of the hole, curing the film to a solid and electroplating a layer of metal on the conductive ink film. The conductive ink preferably is a composition including conductive particles such as carbon and silver flakes. The ink also preferably includes a thermosetting or radiation curable binder and a thinner. The film of ink is cured before the layer of metal is electroplated thereon. The plated through-hole is protected from the etchant when the conductors are etched by placing a radiation curable putty material into the hole, curing it, and then depositing a layer of resist on top of the cured putty and a conductive sheet clad to the substrate of the circuit board.

Plated through-holes in a printed circuit board

An anode used in electroplating is formed by a plurality of individual anode segments. The anode segments are arranged in predetermined patterns. The segments of certain patterns are selectively energized to establish an effective anode size that relates to the size of the article to be electroplated, thereby establishing an electrical field of uniform characteristics to transfer ions from the anode to the article at a uniform deposition rate over the whole surface of the article. By adjusting the effective size of the anode to correspond or relate to the size of the article, the non-uniform deposition rates associated with concentrated localized field are avoided, and the physical size of the electroplating apparatus can be reduced. An electrophoretic ion filter is also placed between the cathode and the article. This ion filter is preferably formed of a plastic porex material, such as porous polypropylene or polyethylene.

Variable size segmented anode array for electroplating

Plated through holes in a printed circuit board can be conveniently produced during manufacture of the circuit board under the control of a computer controlled plotter by the use of a pen-like instrument which positively displaces a thick film fluid conductive adhesive on a tip of the instrument. The fluid is smeared onto the side walls of the hole by moving the tip in a peripheral motion around the side wall of the hole. Copper is electroplated directly onto the conductive adhesive. Resist material is applied in a similar fashion prior to etching the circuit traces on the surface sheets of the circuit board.

Forming plated through holes in a printed circuit board by using a

A conductor clad board from which the printed circuit board is produced is operatively retained for manipulation in a plotter controlled by a computer. Etchant-resist material is laid down in a printed circuit conductor pattern on at least one conductive sheet of the board by a marking instrument operatively manipulated by the plotter. The computer controls the application of the resist material in accordance with printed circuit board computer aided design information in the computer memory. Both conductive sheets of the board can be marked with resist after establishing the orientation of the board so the printed circuit patterns on opposite sides of the board occupy a predetermined aligned relationship. After etching, the board is again retained in the plotter and holes are drilled through the board by using drill apparatus operatively adapted for use and manipulation by the plotter.

Process for use in rapidly producing printed circuit boards using a

Drilling apparatus is adapted for use with a computer controlled plotter to selectively use the plotter as an automatically positionable hole drilling device. A drill motor of the drilling apparatus is carried and manipulated by a carrier mechanism of the plotter in a manner similar to that in which a conventional plotter instrument is manipulated. A coupling apparatus is attached to the carrier mechanism for the purpose of selectively mechanically connecting to and establishing a pneumatic seal for supplying pressurized gas to operate the drill motor. An alignment apparatus is connected between the carrier mechanism and the drilling apparatus to position an axis through the drill bit of the drill motor orthogonal to the plotter table. An actuator apparatus moves the drill motor toward the plotter table to drill holes in the material positioned on the plotter table.

Drill apparatus for use with computer controlled plotter

An optical sight for a computer controlled plotter includes a magnifying lens positioned in an image path through the sight. The magnifying lens magnifies the image of the reference point located by the sight about an optical axis through the sight. The magnification achieves greater accuracy in locating the reference point. An electronic device which responds to light impinging thereon is positioned in the image path at the optical axis. Position signals supplied by the electronic means are related to the location of the impinging light of the reference point relative to the optical axis. The position signals are used by a computer controlling the plotter to manipulate the plotter to automatically locate the reference point.

Optical sight for computer controlled plotter with improved locating

The horizontal and vertical deflection factors for a split anode beam penetration color CRT are compensated for changes and remain constant as trace color is varied. In an electro-statically deflected tube a correction lens near an expansion mesh and electrically connected to the split anode faceplate alters the radial velocities of electrons leaving the mesh such that their point of impact upon the faceplate is unaffected by changes in axial velocity induced to change trace color. In a magnetically deflected tube a correction lens in the neck near entrance to the deflection yoke is supplied with a voltage that varies in conjunction with that of the faceplate. The axial velocity of the electrons in the region of magnetic deflection is adjusted to produce amounts of deflection that remain constant despite changes in the faceplate voltage.

Beam penetration CRT with internal automatic constant deflection factor

The magnitude of a DC high voltage supplied to an internal element of a CRT is varied by a thermionic valve that is located within the envelope of the CRT and that forms a voltage divider with an external load resistor. Only a small scale signal referenced near ground is needed to produce a several thousand volt change in the high voltage supplied to the internal CRT element. The variable high voltage may control a variable deflection factor, variable spot size, or in the case of a beam penetration CRT, either variable persistence or variable trace color. In a particular beam penetration color CRT having a split anode the thermionic valve comprises a tetrode flood gun coupled by an electron mirror to a plate region in the neck of the CRT.

Growing community of inventors

Colorado Springs, CO, United States of America

Ronald G Reed