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Publication numberUS3676943 A
Publication typeGrant
Publication dateJul 18, 1972
Filing dateJul 27, 1970
Priority dateJul 27, 1970
Publication numberUS 3676943 A, US 3676943A, US-A-3676943, US3676943 A, US3676943A
InventorsThomas L Kidd Jr, Albert D Mcclain Jr
Original AssigneeGen Electric
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Non-flammable, thin, integrally illuminated control panel overlay
US 3676943 A
A non-flammable control panel overlay with legible indicia openings, integral illumination and integral supporting means comprises a metallic member with indicia openings on the front thereof backed by a non-flammable, transparent backing member mounted in a recessed area on the back of the member behind the indicia openings, an electroluminescent lamp mounted in a second recessed area behind the transparent backing member and ribs on the back side of the member comprising the unetched areas left when the various mounting recesses are formed. Such a metallic overlay is made by mechanically engraving the indicia, on the front of a metal blank and then chemically etching the rear of the blank, in a stepwise fashion to form the various recesses and remove unnecessary material, until breakthrough to the indicia occurs.
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Description  (OCR text may contain errors)

United States Patent Kldd, Jr. et a]. [451 July 18, 1972 [541 NON-FLAMMABLE, THIN, 3,284,941 11/1966 Kaup .40/130 M INTEGRALLY ILLUMINATED 2,707,346 5/1955 Fuller, Jr. ..40/l33 CONTROL PANEL OVERLAY Primary ExammerRobert W. Michell [72] Inventors: Thomas L. Kidd, Jr., Norristown; Albert Assistant Examiner-Richard Carter D. McClain, Jr., Philadelphia, both of Pa. AttorneyPaul F. Prestia, Allen E. Amgott, Melvin M. Goldenberg, Henry W. Kaufmann, Frank L. Neuhauser and Oscar [73] Ass1gnee. General Electric Company B wadde" [22] Filed: July 27, 1970 [21] Appl. No.: 64,879 [57] ABSTRACT A non-flammable control panel overlay with legible indicia Related ApPucafinn openings, integral illumination and integral supporting means [62] Division of 706,044 6 1968 Patent comprises a metallic member with indicia openings on the 3 ,5 80 7 5 5 front thereof backed by a non-flammable, transparent backing member mounted in a recessed area on the back of the 52 us. Cl 40/130M 40/133 member behind the indicia elemduminescem [51] Int G09f 13/22 lamp mounted in a second recessed area behind the trans- [58] Field of Search ..4o/i'5dM"i'55"'i'33 A 133B backing member and ribs the back Side member comprising the unetched areas left when the various [56] References cued mounting recesses are formed. Such a metallic overlay is made by mechanically engraving the indicia, on the front of a metal UNITED STATES PATENTS blank and then chemically etching the rear of the blank, in a 3 4 stepwise fashion to form the various recesses and remove uni'g 'ggg i a necessary material, until breakthrough to the indicia occurs.

u er 3,038,271 6/1962 Macl-lutchin et al ..40/130 M 2 Claims, 4 Drawing Figures NON-FLAMMABLE, THIN, INTEGRALLY ILLUMINATED CONTROL PANEL OVERLAY This application is a division of our application Ser. No. 706,044, filed Feb. 16, 1968, now US. Pat. No. 3,580,755.

INTRODUCTION The invention herein described was made in the course of or under a contract with the Department of the Air Force.

This invention relates to a non-flammable control panel overlay suitable for use in aircraft and spacecraft. More specifically it pertains to such overlays which are thin, selfsupporting and integrally illuminated.

BACKGROUND OF THE INVENTION In the interest of weight reduction and space saving in and around the cockpit areas of aerospace vehicles, numerous efforts have been made to reduce the weight and volume of control panel display assemblies. Among the results of these efforts are displays which include a panel overlay comprised of transparent plastic material with electroluminescent or small incandescent lamps embedded therein. Replacement of individual embedded lamps in these overlays without replacement of the whole overlay is difficult if not impossible. Further, because such plastic overlays have little inherent stiffness, they usually require a backing member for support. Undesirable extra weight results because of the use of such support.

The biggest disadvantage of these plastic overlays, however, is their flammability. The organic matter contained in these overlays adds to the fire hazard present in any cockpit. Minimization of this hazard is one of the objectives of the present invention.

While metallic control panel displays would avoid the flammability problem of plastic overlays, no practical means for providing integrally illuminated indicia therein has been known. In addition to the bulk and weight of bulbs, sockets and mountings therefor, another factor inhibiting the use of metallic displays has been difficulty in producing clear lettered indicia openings in thin metallic face members. The

present invention is also directed to that problem.

A general object of the present invention is to provide a thin, non-flammable, integrally illuminated panel assembly.

Another object is to provide a non-flammable, lightweight, integrally illuminated, self-supporting panel overlay.

A further object of this invention is to provide an inexpensive, easily manufactured, integrally illuminated, non-flammable panel overlay including highly legible illuminated character openings therein.

It is also an object to provide improved methods for making metallic control panel overlays with precisely formed character openings therein.

BRIEF DESCRIPTION OF THE INVENTION These and other objects are met, in accordance with the present invention, by a metallic overlay with indicia openings therein, a non-flammable, flat, transparent backing member mounted in a recessed area behind the indicia openings, and an electroluminescent lamp mounted in a second recessed area behind the transparent backing member. The overlay may also include integral supporting ribs on the back side thereof.

The necessary character openings and recesses and integral reinforcement ribs on the back side of the overlay are made preferably by mechanically engraving the front of the overlay in the shape of the character openings desired and applying a temporary support material, such as a maskant, to the whole overlay including the first engraved areas. Recesses are then chemically etched, in stages, on the back of the overlay, exposing from the reverse side the previously engraved characters and providing mounting seats for a permanent transparent support member behind the etched character openings and for an electroluminescent lamp behind the transparent support member. Unetched areas on the back of the overlay provide integral supporting ribs therefor.

DETAILED DESCRIPTION OF THE INVENTION While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter of the present invention, this invention may be better understood from the following description, taken in conjunction with the following drawings, in which:

FIG. 1 is a front view of a control panel overlay comprising the preferred embodiment-of the present invention;

FIG. 2 is a rear view of the overlay shown in FIG. 1;

FIG. 3 is a cross section of the overlay shown in FIGS. 1 and 2; and

FIG. 4 is a rear view of a metal blank engraved and etched in accordance with the present invention to produce the overlay shown in FIGS. l-3.

Referring more specifically to FIG. 1 there is shown an anodized aluminum overlay l with indicia openings 2 and a control switch 3.

In FIG. 2 the rear of overlay 1 is seen with switch 3 removed. Also seen in FIG. 2 are integrally formed supporting ribs 4 for the overlay 1 and electroluminescent lamps 5 including necessary connectors and wiring.

A cross section of the same control panel overlay is shown in FIG. 3, in which is also shown, a flat transparent backing member 6, specifically a piece of zinc borosilicate glass, mounted behind indicia openings 2 in a recessed area 7. Mounted behind backing member 6 in a second recessed area 8 is an electroluminescent lamp 5. The connectors and connecting wire for electroluminescent lamp'5 as well as control switch 3 is omitted from FIG. 3 for purposes of clarity.

Other materials may, of course, be substituted for those described above. However, the overlay 1 will generally be comprised of a metallic material for purposes of non-flammability. Zinc borosilicate glass is selected in the preferred form of the present invention for the transparent backing member because of its flexibility and high temperature resistance relative to other glasses and for its non-flammability relative to plastics. Transparent backing member 6, bonded generally with a chemically adhesive such as an epoxy cement in recessed area 7, supports the free centers of indicia openings 2. Backing member 6 may be tinted to control color or brightness in the illuminated indicia openings.

In use, the metallic overlay of the present invention is either assembled with a dust cover on the back thereof or mounted on some form of control panel backing member.

To produce the highly legible indicia openings in the overlays of the present invention, the indicia are first mechanically engraved on one side of a metal blank to a uniform depth somewhat less than the blank thickness. The remaining unengraved thickness holds the free centers of the indicia characters and makes possible very precise character formation. Support material is then applied to the engraved side of the blank and the reverse side is chemically etched. When this process is complete the thickness of the blank in the area surrounding the indicia is sufficiently reduced to expose the indicia on the reverse side of the blank. Openings in the shape of complex indicia characters are thus formed with good precision. In the process of chemical etching the back side of the indicia, mounting recesses for backing member 6 and lamps 5 may also be formed and excess material around integral supporting ribs may be removed.

For example, the metallic overlay shown in FIGS. l-3 was made from a five inch by seven inch blank of 0.091 inch thick 7075-T6 aluminum. (In other examples, 606l-T6 aluminum has also been used with equal success. These materials are commercially recognized as structural grade aluminum alloy.)

A rear view of this metal blank following engraving and etching is seen in FIG. 4. The indicia were formed on one side of the blank, by mechanical engraving, to a flat depth of 0.01 inch, with a cutter having a side taper on the order of 3. Generally the width of the indicia character lines was about 0.026 inch and the ratio of line length to line width was about 6 to l.

To control glare from the front. of the panel and to improve its appearance, the blank was anodized, by a conventional anodization process, after it had been mechanically engraved.

A chemical etch maskant coating, specifically Organocerame, Inc. maskant no. 1-1010, was then flow coated on both sides of the blank. After allowing the maskant to dry it was cut and removed in the area defining backing member recess 7. This exposed area was then etched to a depth of 0.01 inch with a conventional sodium hydroxide etchant bath at l80200 F. Typically, this bath was made up of ounces of sodium hydroxide crystals, 0.3-0.4 ounces of sodium gluconate and 0.2-1.0 ounces of sodium sulfide per gallon of water. (Other maskants, other sodium hydroxide baths, and other types of etchants, such as hydrochloric acid baths, have been used.)

Maskant was then cut and removed from the area defining lamp mounting recess 8 and the area 9 surrounding supporting ribs 4 which are alternatively describable as unrecessed areas. These areas were etched with the conventional sodium hydroxide etchant described above until breakthrough to the flat bottomed indicia engraving was achieved. The recessed areas produced by the two step etching process just described are seen most clearly in FIG. 4.

The complex indicia characters thus formed by the combined mechanical engraving-chemical etch procedure of the present invention are much superior in sharpness and legibility to any heretofore known to have been produced by either mechanical or chemical means alone.

In order to complete the metallic overlay produced as described above, it is necessary to provide a permanent supporting means for the area surrounding, and the free centers of the indicia openings. It is also necessary to remove the remaining maskant from the overlay.

In the preferred form of the present invention a zinc borosilicate backing member 6 is bonded with a conventional epoxy cement in recess 7. A problem arises however in that the epoxy cement makes it difficult to remove the maskant from the front of the overlay. Therefore it has been found best to apply a polyvinyl alcohol (PVA) parting layer and a silicone rubber overcoat to the back of the indicia after the chemical etching process. The maskant is then easily removed from the front of the overlay and a PVA parting layer and silicon rubber overcoat is applied to the front of the overlay. After removing the previously applied PVA-silicone from the back thereof, the glass backing member may be permanently bonded in place. The PVA-silicone on the front of the metallic panel overlay is then easily removed without damage to the indicia openings.

While the foregoing invention has been described with reference to particular embodiments thereof for purposes of clarity and convenience, it should be understood that numerous modifications may be made by those skilled in the art without departing from the inventions true spirit and scope. Therefore the appended claims are intended to cover all such equivalent variations as come within the true spirit and scope of the present invention.

What we claim as new and desire to secure by letters patent of the United States is: y

l. A control panel overlay comprising a thin, sheet-like metallic member having a first recessed area on the back thereof, a second recessed area within and smaller than said first recessed area, indicia openings through said overlay in said second recessed area, a flat, transparent backing member for support of said indicia openings and the free centers surrounded by said openings, said backing member conforming to the shape of and seated in said second recessed area, and an electroluminescent lamp conforming to the shape of and seated in said first recessed area.

2. A control panel overlay, as recited in claim 1, further including additional recessed areas of predetermined shape and depth, the unrecessed areas surrounding all of said recessed areas being adapted to provide integral structural support to the overlay. at

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2155936 *Oct 29, 1937Apr 25, 1939Hermon A FullerElectric sign
US2707346 *Sep 9, 1952May 3, 1955Fuller Jr Thomas J DIlluminated translucent signs
US3038271 *Jul 22, 1959Jun 12, 1962United States Radium CorpSelf-luminous signs
US3284941 *Sep 19, 1963Nov 15, 1966Felsenthal Instr IncIlluminated panel and method for making same
US3404474 *Jun 21, 1965Oct 8, 1968James F. JohnsonLighted sign
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4619624 *Sep 30, 1985Oct 28, 1986Kerr Iii CharlesMethod of making improved electroluminescent panels
US4667273 *Aug 30, 1985May 19, 1987VibrachocElectroluminescent panel and method for manufacturing same
US5114157 *Jun 11, 1990May 19, 1992Snk CorporationGame machine having plural display panel units and plural memory cartridges
US5747757 *Sep 10, 1996May 5, 1998Monopanel Technologies, Inc.Tamper resistant membrane switch
US5987793 *Jan 16, 1998Nov 23, 1999Sony CorporationIlluminative display device and electronic apparatus equipped with same
US6137072 *May 26, 1999Oct 24, 2000Ferro CorporationControl panel
U.S. Classification40/544, 40/580
International ClassificationG09F13/04, B60Q3/04, G09F13/22
Cooperative ClassificationG09F13/04, B60Q3/044, G09F2013/227, H01H2009/186
European ClassificationB60Q3/04B, G09F13/04