Patent US3574933A successfully refreshed from Google Patents.
US3574933A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making printed circuit boards with plated-through holes
Assignee: GTE Sylvania Inc
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Filing: 1968-11-29
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Granted: 1971-04-13
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Expires: 1988-11-29
Abstract
Abstract Artwork for printed circuit boards with plated-through holes is made with terminal area pads having center openings covered with an optical filter, preferably a colored strip. By appropriately filtering light passing through the artwork, two master transparencies are made photographically, one with and the other without center hole images corresponding to the center openings in the pads. The transparency with such images is used to expose a photosensitized copper-clad board for locating centers of the holes preparatory to drilling of the board. The transparency without center hole images is used to transfer the same circuit pattern to the drilled board after the holes have been metallized and the board is again photosensitized. The board is plated with etch-resistant metal, stripped and finally is etched to complete the circuit pattern on one or both sides of the board.
Inventors
- 👤 Art E Cassingham
- 👤 Arvin C Skyrud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:00
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/0073; H05K3/0082; H05K3/40; H05K3/42; H05K1/00; H05K1/02; H05K1/11; H05K1/115; H05K1/116; H05K2203/00; H05K2203/05; H05K2203/0548; H05K2203/056; H05K3/0002; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/49155; Y10T29/49156
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
118 words
The method of making a printed circuit board with platedthrough holes consisting of the steps of; forming a circuit pattern on an art sheet with conductor termination pads having center openings; photographically making a first transfer master having the image of said art sheet circuit pattern including said pad openings; photographically making a second transfer master having the image of said art sheet circuit pattern without images of the pad openings; imaging a side of a board through said first master and forming holes in the board coincident with the pad opening images and thereafter plating the sides of said holes; and imaging the perforate board through said second master and permanently forming the desired circuit pattern thereon.
Claim 2
Independent Claim
118 words
The method of making a printed circuit board with platedthrough holes consisting of the steps of; forming a circuit pattern on an art sheet with conductor termination pads having center openings; photographically making a first transfer master having the image of said art sheet circuit pattern including said pad openings; photographically making a second transfer master having the image of said art sheet circuit pattern without images of the pad openings; imaging a side of a board through said first master and forming holes in the board coincident with the pad opening images and thereafter plating the sides of said holes; and imaging the perforate board through said second master and permanently forming the desired circuit pattern thereon.
Claim 3
Dependent Claim
24 words
The method according to claim 1 in which the making of the second transfer master includes optically filtering out images of the pad openings.
Claim 4
Dependent Claim
20 words
The method according to claim 2 in which light is color filtered as it passes through the pad center openings.
Claim 5
Dependent Claim
22 words
The method according to claim 2 in which certain wavelengths of the light are blocked upon passage through the pad center openings.
Claim 6
Independent Claim
177 words
The method of making a printed circuit board with plated-through holes consisting of the steps of; forming a circuit pattern on an art sheet with conductor termination pads having center openings covered with optical filters; exposing photographic film to light passing through said art sheet including said pad center openings and making a first transparency of the circuit pattern with images of the pad center openings; similarly exposing photographic film to light passing through said art sheet but optically blocking light passing through the filters in the pad center openings and making a second transparency of the circuit pattern without images of the pad center openings; transferring the pattern image of the first transparency to a circuit board and forming holes through said board on centers located by images of the pad center openings; covering the sides of said holes in said perforate board with an electrically conductive coating; transferring the pattern image on the second transparency to the circuit board in registration with the holes formed therein; and forming said circuit pattern permanently on said board.
Claim 7
Independent Claim
177 words
The method of making a printed circuit board with plated-through holes consisting of the steps of; forming a circuit pattern on an art sheet with conductor termination pads having center openings covered with optical filters; exposing photographic film to light passing through said art sheet including said pad center openings and making a first transparency of the circuit pattern with images of the pad center openings; similarly exposing photographic film to light passing through said art sheet but optically blocking light passing through the filters in the pad center openings and making a second transparency of the circuit pattern without images of the pad center openings; transferring the pattern image of the first transparency to a circuit board and forming holes through said board on centers located by images of the pad center openings; covering the sides of said holes in said perforate board with an electrically conductive coating; transferring the pattern image on the second transparency to the circuit board in registration with the holes formed therein; and forming said circuit pattern permanently on said board.
Claim 8
Dependent Claim
48 words
The method according to claim 5 in which the art sheet circuit pattern is made with pads having center openings covered with translucent colored strips; and disposing a colored filter between the art sheet and film for blocking light from said pad openings in making said second transparency.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |