Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Ophthalmic lenses or blanks
Reexamination Certificate
1998-04-30
2001-04-10
Lam, Cathy (Department: 1775)
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Ophthalmic lenses or blanks
C359S245000
Reexamination Certificate
active
06213602
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method for applying an electrical contact system to a substrate, and to the resulting metallized substrate. A preferred embodiment involves applying a tab to a conductive metal bus bar on an optical substrate, such as an ophthalmic lens, using a bonding agent and, if necessary, a conductive intermediate. The instant method is particularly useful in preparing electrooptic devices, such as electrochromic lenses.
BACKGROUND OF THE ART
The transmittance properties of electrochromic materials change in response to electrically driven changes in oxidation state. Thus, when an applied voltage from an external power supply causes electrons to flow to (reduction) or from (oxidation) an electrochromic material, its transmittance properties change. In order to maintain charge neutrality, a charge balancing flow of ions in the electrochromic device is needed. By enabling the required electron and ion flows to occur, an electrochromic device facilitates reversible oxidation and reduction reactions during optical switching.
Conventional electrochromic cells comprise at least one thin film of a persistent electrochromic material, i.e. a material responsive to the application of an electric field of a given polarity to change from a high-transmittance, non-absorbing state to a low-transmittance, absorbing or reflecting state. Since the degree of optical modulation is directly proportional to the current flow induced by an applied voltage, electrochromic devices demonstrate light transmission tunability between high-transmittance and low-transmittance states. In addition, these devices exhibit long-term retention of a chosen optical state, requiring no power consumption to maintain that optical state. Optical switching occurs when an electric field of reversed polarity is applied.
To facilitate the aforementioned ion and electron flows, at least one electrochromic film which is both an ionic and electronic conductor is in ion-conductive contact, preferably direct physical contact, with an ion-conducting material layer. The ion-conducting material may be inorganic or organic, solid, liquid or gel, and is preferably an organic polymer. The electrochromic film(s) and ion-conductive material are disposed between two electrodes, forming a laminated cell. As voltage is applied across the electrodes, ions are conducted through the ion-conducting material.
When the electrode adjacent to the electrochromic film is the cathode, application of an electric field causes darkening of the film. Reversing the polarity causes reversal of the electrochromic properties, and the film reverts to its high-transmittance state. Typically, an electrochromic film such as tungsten oxide is deposited on a substrate coated with an electroconductive film such as tin oxide or indium tin oxide to form one electrode. The counter electrode is typically a similar tin oxide or indium tin oxide coated substrate. A complimentary electrochromic film, for example an iridium oxide film, can also be used.
An electrochromic device, such as an electrochromic lens, also requires a means for delivering electrical current from a power source to each of its electrodes. This can be accomplished via use of a bus bar, as disclosed in U.S. Pat. Nos. 5,520,851 and 5,618,390 to Yu, et al.
U.S. Pat. No. 5,471,338 to Yu, et al., discloses the use of a conductive silver epoxy bus bar to make electrical connection to an electrochromic device.
U.S. Pat. No. 3,630,603 to Letter discloses an electrochromic eyewear control circuit. U.S. Pat. No. 4,991,951 to Mizuno discloses metal eyeglass frames used in conjunction with electrooptic lenses.
U.S. Pat. No. 4,335,938 to Giglia discloses electrochromic devices having a layer of tungsten oxide in contact with a layer of organic electrolyte resin comprising a hydrophilic layer of 2-acrylamido-2-methylpropanesulfonic acid homopolymer and an electrode means for changing electrochromic properties of the device.
U.S. Pat. No. 5,327,281 to Cogan discloses the use of epoxy to seal a cavity formed when a spacer is used to separate electrodes and contains a liquid electrolyte injected between the spaced electrodes.
U.S. Pat. No. 5,657,150 to Kallman, et al., discloses electrochromic devices and the use of contacts connecting first and second electrodes to flex circuits or other means of wiring.
SUMMARY OF THE INVENTION
This invention is directed to a method for applying conductive metal bus bar/tab systems to various substrates and to the resulting metallized substrates. More particularly, this method involves applying a conductive metal bus bar and tab to the bus bar target area of a substrate having a peripheral edge region situated between first and second expanse surfaces in a manner which provides reliable electrical contact between the tab and bus bar, and which allows the bus bar and tab to be used as electrical conduits between a power source and an electrode disposed on the substrate, preferably on one of the substrates' expanse surfaces.
For example, in electrooptic applications, a bus bar comprising a conductive metal coating is applied to the peripheral edge region of an optical substrate having or which will have an electroconductive film on an adjacent expanse surface. The conductive metal coating and electroconductive film are disposed so as to overlap at or near the interface of the peripheral edge region and the expanse surface. The connecting portion of a tab, preferably its connecting end, is affixed to the metal coating in a manner which ensures electrical contact, for example via use of a suitable solder or conductive bonding agent, or a non-conductive bonding agent in conjunction with a conductive intermediate.
As used herein, the term ‘bus bar’ refers to a strip, coating or band of one or more low resistance, electrically conductive metals or metal alloys that is applied to a substrate. A bus bar is generally positioned so that it is in contact with or will contact an electroconductive material disposed on the substrate. As such, bus bars can be used to distribute electrical current from a power source across an electroconductive film. The term ‘tab’, as used herein, refers to a conductive wire or strip which links or connects a bus bar to a power source through a circuit, for example an electrooptic or electrochromic control circuit. A tab, which can be either an integral part or a separate component of such a circuit, is generally affixed to a bus bar at a connecting end, though this invention contemplates tab connection along any portion of its surface.
A conductive metal bus bar preferably is applied to the peripheral edge region of a substrate having or which will have a metal or metal oxide electroconductive film (e.g., fluorine-doped tin oxide, tin-doped indium oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, etc.) on an adjacent expanse surface (hereinafter referred to as an electroconductive expanse surface). Electrical contact between the bus bar and an electroconductive film is preferably made at the interface of the peripheral edge region and an electroconductive expanse surface of a given substrate by causing the electroconductive film on the expanse surface to overlap the bus bar, or vice versa. It is desirable that a bus bar have a lower electrical resistance than the electroconductive film that it contacts. For example, bus bar sheet resistances of less than 20 ohms/sq. are preferred when electroconductive films having sheet resistances of 20-25 ohms/sq. are used.
In one embodiment of the instant invention, a conductive metal bus bar, e.g., a gold, chromium or silver-containing metal coating, is applied to the peripheral edge region of a shaped substrate using a conventional deposition technique, with masking as needed. As used herein, the term ‘shaped substrate’ refers to a substrate prepared by grinding or cutting the perimeter of an oversized blank substrate to a smaller size having a desired shape. This grinding process is commonly referred to as edging. For ophthalmic lenses, disk-shaped, oversized blank le
Lam Cathy
Marmo Carol A.
Mitchell William C.
PPG Industries Ohio Inc.
LandOfFree
Metal bus bar and tab application method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Metal bus bar and tab application method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metal bus bar and tab application method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2527468