Source: http://www.google.com/patents/US4410790?ie=ISO-8859-1&dq=5,266,072
Timestamp: 2014-03-13 06:35:56
Document Index: 169409752

Matched Legal Cases: ['art 12', 'art 12', 'arts 12', 'art 12', 'art 12', 'art 12']

Patent US4410790 - Heated automobile mirror - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsAn economical mirror unit adapted for exterior mounting on an automobile has a single self-regulating electrical resistance heater disc of a material of positive temperature coefficient of resistivity mounted in a recess on a heat-distributing metal plate and enclosed in the recess by a glass reflecting...http://www.google.com/patents/US4410790?utm_source=gb-gplus-sharePatent US4410790 - Heated automobile mirrorAdvanced Patent SearchPublication numberUS4410790 APublication typeGrantApplication numberUS 06/328,322Publication dateOct 18, 1983Filing dateDec 17, 1981Priority dateDec 17, 1981Fee statusLapsedPublication number06328322, 328322, US 4410790 A, US 4410790A, US-A-4410790, US4410790 A, US4410790AInventorsPeter G. Berg, Stephen J. StrobelOriginal AssigneeTexas Instruments IncorporatedExport CitationBiBTeX, EndNote, RefManPatent Citations (8), Referenced by (22), Classifications (13), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetHeated automobile mirrorUS 4410790 AAbstract An economical mirror unit adapted for exterior mounting on an automobile has a single self-regulating electrical resistance heater disc of a material of positive temperature coefficient of resistivity mounted in a recess on a heat-distributing metal plate and enclosed in the recess by a glass reflecting member mounted over the recess so that the heater serves to defog the reflecting surface of the member. Various portions of the plate have selected different spacings from the glass reflecting member for heating various overlying portions of the reflecting member to a substantially uniform temperature so that the heater is operable at a high temperature to rapidly and uniformly defog the mirror without risk of damage to the glass reflecting member.
We claim: 1. A defogging mirror unit comprises a plate of thermally and electrically conductive metal material formed to provide a recess at one side of the plate, a self-regulating electrical resistance heater of a material of positive temperature coefficient of resistivity having one side mounted in electrically and thermally conducting relation to said one side of the plate inside the recess, contact means for electrically connecting the other side of the heater to a power source for energizing the heater to self-heat and stabilize at a relatively high self-regulated heater temperature, and a glass reflecting member disposed over the plate recess enclosing the heater in the recess so that heat from the heater is distributed to the glass reflecting member for defogging the member, characterized in that, a first part of the plate mounts the heater thereon and forms a central bottom portion of the recess having a first selected spacing from the glass reflecting member for heating a portion of the member overlying the first plate part to a selected temperature, at least one additional plate part forms at least one additional recessed bottom portion surrounding the central recess bottom portion having relatively lesser spacing from the glass reflecting member for heating portions of the member overlying each said additional plate part to corresponding temperature, and peripheral parts of the plate disposed around said additional plate part mount marginal portions of the glass reflecting member thereon and have relatively lesser spacing from the member than the additional plate part for heating said marginal portions of the member to corresponding temperature, whereby heat is distributed to the member for heating said various portions of the member to a substantially uniform temperature.
BACKGROUND OF THE INVENTION The field of this invention is that of defogging mirror units and the invention relates more particularly to a defogging automobile mirror using an electrical resistance heater for defogging the mirror.
SUMMARY OF THE INVENTION Briefly described, the novel and improved defogging mirror unit of this invention comprises a plate of thermally and electrically conductive metal material or the like. The plate is formed to provide a recess in the plate at one side of the plate. An electrical resistance heater of a material of positive temperature coefficient of resistivity is mounted in the plate recess with one side of the heater in electrically and thermally conducting relation to the plate and contact means are arranged for electrically connecting the other side of the heater to a power source such as the battery power source of an automotive engine or the like for energizing the heater. The heater is adapted to self-heat and stabilize at a self-regulated heater temperature in conventional manner. A glass reflecting member is disposed over the plate recess for enclosing the heater in the recess.
DESCRIPTION OF THE DRAWINGS Other objects, advantages and details of the novel and improved defogging mirror unit of this invention appear in the following detailed description preferred embodiments of the invention, the detailed description referring to the drawings in which:
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, 10 in FIGS. 1 and 2 indicates the novel and improved heated defogging mirror unit of this invention which is shown to include an electrically and thermally conducting heat-distributing metal plate 12 preferably formed of an inexpensive, light weight, and readily formable material such as aluminum. Preferably the plate is of generally flat configuration as indicated and in accordance with this invention, the plate is formed to provide a recess or well 14 in the plate to be accessible from one side 12a of the plate.
In accordance with this invention, a heater body or disc 16 of a ceramic electrical resistance material or the like having a positive temperature coefficient of resistivity (PTC) is disposed in the recess 14 with one side of the heater disc in electrically and thermally conducting relation to the plate 12. Preferably, the heater disc is formed of a doped barium titanate ceramic material or the like and is adapted to display a sharp, anomolous increase in resistivity when heated to a selected temperature so that the heater self-heats and stabilizes at a self-regulated operating temperature of about 150 energized. The heater disc is provided with metal contact coatings 16.1 and 16.2 on opposite sides of the heater disc for making electrical contact to the ceramic resistance material of the disc.
In that arrangement, one side 16.2 of the heater is electrically connected from the power source 32 through the wire lead 28 and the spring blade 18 and the other side 16.1 of the heater is connected to electrical ground through the plate 12 and the lead 26. When the heater is energized, it generates heat for defogging the glass reflecting member 22. The plate 12 distributes heat to the glass reflecting member as indicated by the waving lines 34 in FIG. 2. In accordance with this invention, the first plate part 12.1 mounting the heater thereon is spaced at a distance D.sub.1 from the glass reflecting member 22 so that the overlying portion D'.sub.1 of the glass reflecting member is heated to a desirable defogging temperature. An additional plate part 12.2 is spaced at a lesser distance D.sub.2 from the glass member, and the peripheral plate parts 12.4 mount the glass member at a relatively lesser spacing from the member 22 or are even directly engaged with the member as indicated at D.sub.3 in FIG. 2, those spacings being selected so that they distribute heat to corresponding overlying portions D'.sub.2 and D'.sub.3 of the glass reflecting member for heating those portions of the reflecting member to corresponding defogging temperatures, thereby to heat the various portions of the member to substantially uniform defogging temperature. If the support means 24 tends to withdraw heat from a plate part 12.3 or the like at a rate different from the rate at which heat is dissipated from other portions of the plate 12, the spacing D.sub.4 of the plate part 12.3 from the glass reflecting member is selected to compensate for that difference to assure that uniform defogging heating of the reflecting member is achieved. In that regard, it is found that spacing of the plate part 12.1 at a distance of about 0.075 inches from the member 22 permits the noted relatively high operating temperature of the heater to be used without risk of injury to the glass reflecting member while a spacing D.sub.2 of about 0.015 inches and a spacing D.sub.3 of 0.000 inches achieves relatively uniform heating of the member 22 at a defogging temperature suitable for the range of temperatures likely to be encountered in use of an automobile. A spacing D.sub.4 of about 0.010 inches from the member 22 compensates for the relatively lesser heat dissipation likely to occur at the rear of the plate 12 where the metal support means 24 has a configuration such as that indicated in FIG. 1. In that way, the mirror unit 10 has a rugged low cost structure and is adapted to permit rapid and uniform defogging of the mirror unit under different environmental conditions without risk of injury to the glass reflecting member 22.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS2564836 *Feb 2, 1949Aug 21, 1951Charles Parker CompanyNonblurrable mirrorUS2565256 *Apr 4, 1949Aug 21, 1951Myers James DHeated mirrorUS3052787 *Aug 31, 1959Sep 4, 1962Gen Motors CorpHeated mirrorUS3940822 *Feb 19, 1975Mar 2, 1976All Weather Truck Mirror Co., Inc.Rear view safety mirrorUS3976854 *Jul 31, 1974Aug 24, 1976Matsushita Electric Industrial Co., Ltd.Constant-temperature heaterUS3996447 *Nov 29, 1974Dec 7, 1976Texas Instruments IncorporatedPTC resistance heaterUS4237366 *Mar 19, 1979Dec 2, 1980Texas Instruments IncorporatedHeated automobile mirrorUS4283117 *Dec 10, 1979Aug 11, 1981Ellis Harold GSide view mirror apparatus for vehicles* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS4631391 *Jun 21, 1984Dec 23, 1986Stettner & Co.Electrical heating device, especially for mirrorsUS5079406 *Jul 12, 1990Jan 7, 1992Laszlo NagyHeating device using a voltage stabilizerUS5285054 *Mar 6, 1992Feb 8, 1994Air-Shields, Inc.Thermal probe having resiliently biased temperature sensor for use with heatable panelsUS5352869 *Feb 8, 1994Oct 4, 1994Air-Shields, Inc.Heatable transparent panel structure utilizing thermal probe having resiliently biased temperature sensorUS5446576 *Nov 4, 1992Aug 29, 1995Donnelly CorporationElectrochromic mirror for vehicles with illumination and heating controlUS5459533 *Nov 12, 1993Oct 17, 1995See Clear Eyewear Inc.Defogging eye wearUS5475530 *Aug 31, 1990Dec 12, 1995Aisin Seiki Kabushiki KaishaOutside mirror for a vehicleUS5594585 *Jun 13, 1995Jan 14, 1997Murakami Kaimeido Co., Ltd.Vehicle mirrorUS5610756 *May 17, 1995Mar 11, 1997Donnelly CorporationElectrochromic mirror for vehiclesUS5749118 *Feb 5, 1993May 12, 1998Holland; Dewey T.Heated wiper bladeUS5808777 *Mar 3, 1997Sep 15, 1998Donnelly CorporationElectrochromic mirror for vehiclesUS6084217 *Mar 29, 1999Jul 4, 2000Illinois Tool Works Inc.Heater with PTC element and buss systemUS6307188 *May 25, 2000Oct 23, 2001Illinois Tool Works Inc.Heater with PTC element an buss systemUS6455823Oct 6, 2000Sep 24, 2002Illinois Tool Works Inc.Electrical heater with thermistorUS6495809Mar 1, 2002Dec 17, 2002Illinois Tool Works Inc.Electrical heater with thermistorUS6644820 *Jan 30, 2002Nov 11, 2003Texas Instruments IncorporatedTemperature stabilized mirror for switching optical signalsUS7009498Mar 5, 2002Mar 7, 2006Lang-Mekra North America, LlcMirror arrangement for motor vehiclesUS7205510Mar 21, 2005Apr 17, 2007W.E.T. Automotive Systems Ltd.Heater for an automotive vehicle and method of forming sameUS7306283Nov 17, 2003Dec 11, 2007W.E.T. Automotive Systems AgHeater for an automotive vehicle and method of forming sameUS7741582Oct 24, 2007Jun 22, 2010W.E.T. Automotive Systems AgHeater for automotive vehicle and method of forming sameUS8507831May 12, 2010Aug 13, 2013W.E.T. Automotive Systems AgHeater for an automotive vehicle and method of forming sameUS8544942May 12, 2011Oct 1, 2013W.E.T. Automotive Systems, Ltd.Heater for an automotive vehicle and method of forming same* Cited by examinerClassifications U.S. Classification219/219, 219/522, 219/541, 338/22.00R, 219/505, 219/203, 359/512International ClassificationH05B3/84, H05B3/14Cooperative ClassificationH05B3/845, H05B3/141European ClassificationH05B3/84E, H05B3/14CLegal EventsDateCodeEventDescriptionDec 26, 1995FPExpired due to failure to pay maintenance feeEffective date: 19951018Oct 15, 1995LAPSLapse for failure to pay maintenance feesMay 23, 1995REMIMaintenance fee reminder mailedFeb 25, 1991FPAYFee paymentYear of fee payment: 8Apr 6, 1987FPAYFee paymentYear of fee payment: 4Dec 7, 1981ASAssignmentOwner name: TEXAS INSTRUMENTS INCORPORATED, DALLAS, TX. A CORFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:BERG, PETER G.;STROBEL, STEPHEN J.;REEL/FRAME:003964/0270Effective date: 19811202RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google