Heated automobile mirror
First 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.
1 Assignment
0 Petitions
Accused Products
Abstract
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.
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Citations
6 Claims
- 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.
Specification