Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1998-12-03
2001-08-07
Young, Lee (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S620000, C338S004000, C427S103000
Reexamination Certificate
active
06269534
ABSTRACT:
FIELD OF INVENTION
The invention relates to a method for producing an electric resistor, in particular a resistance strain gauge, in which an insulating layer and a resistive layer are sequentially applied to a carrier element, as well as to a method for producing a mechano-electric transducer with a resistor thus produced.
BACKGROUND OF THE INVENTION
In accordance with DE 34 29 649 A1, such resistors, which can be used as resistance strain gauges, are known. Such a resistor has a resistive layer applied to a carrier, an electrically non-conducting layer being arranged between the carrier and resistive layer.
The resistive layer and/or the non-conducting layer is either vapor deposited or sputtered onto the carrier.
The carrier to which the layer structure explained above is applied is a small surface in this case. Should such a structure be applied to non-flat surfaces, the mode of procedure described above is no longer possible, since conformity with previously accurately dimensioned electrical properties is no longer ensured.
It is therefore the object of the invention to specify a method for producing an electric resistor which can be applied reliably to carrier elements with non-flat surfaces.
SUMMARY OF THE INVENTION
According to the invention, the object is achieved by virtue of the fact that the insulating layer or the resistive layer is applied to a backing sheet, the side of the backing sheet carrying the insulating layer or resistive layer being covered with a flexible film layer whose adhesion to the insulating layer or resistive layer is stronger than the adhesion of the backing sheet to the insulating layer or resistive layer, and the film layer is peeled with the insulating layer or resistive layer from the backing sheet and applied to the carrier element, the carrier element being heat treated to burn out the film layer and sinter on the insulating layer or resistive layer.
The advantage of the invention consists in that the existing structure is produced on a carrier material in the form of the backing sheet and, after production, is placed on the carrier element with the aid of the transport film in the manner of a decal. Because of this mode of procedure, the desired layer structure can be mounted on any conceivable geometrical shape of the carrier element, and can be sintered to form an adhesively strong layer during the subsequent heat treatment.
A resistor is produced in this way, which adheres reliably to non-flat surfaces of carrier elements even during longlasting mechanical and thermal loading. This is particularly advantageous when the carrier element is a component which is to be mechanically loaded and consists of sinterable material.
It is advantageous for the insulating layer or the resistive layer to be applied to the backing sheet using a printing technique and to be dried. As a result, it is possible not only for simple unstructured layers, but also for structured patterns such as entire resistor networks to be applied to a non-flat surface of a carrier element.
It is possible with the aid of such a production method to produce roll-on structures which have dimensions specified by a computer and which acquire their necessary geometrical structure and tolerances only upon being applied to the non-flat surface.
In a development, after the application of the insulating layer to the backing sheet a resistive layer is applied to this insulating layer, the film layer completely covering the insulating layer and the resistive layer subsequently being arranged.
In this embodiment, both the insulating layer and the resistive layer are arranged on a single backing sheet and are transported with only one film layer.
In one embodiment, the insulating layer is printed onto the backing sheet in the form of a glass frit, and after the drying of the glass frit a conductive paste is printed as resistive layer onto the insulating layer and dried, the film layer subsequently being applied in the form of a synthetic resin film.
As an alternative to this, an insulating layer arranged on a first backing sheet and dried is applied to the carrier element by means of the film layer and heat treated, and subsequently the resistive layer printed on a second backing sheet and dried is arranged on the already heat-treated insulating layer with the aid of a second film layer positioned on it, and subsequently likewise heat treated.
The method has the advantage, depending on the application, both that the entire structure can be produced on one backing sheet and can be transported onto the carrier element from the backing sheet by means of a single film layer, or that also each layer of the structure can be produced individually on a backing sheet. The individually produced layer is likewise positioned on the carrier element by means of a film.
In a method for producing a mechano-electric transducer which has strain-sensitive precision resistors which are applied to an insulating layer arranged on a carrier element, the precision resistors and structures of an electronic evaluation system are applied to a common insulating layer, at least the insulating layer being applied to a backing sheet, the side of the backing sheet carrying the insulating layer being covered with a flexible film layer whose adhesion to the insulating layer is stronger than the adhesion of the backing sheet to the insulating layer, the film layer being peeled with the insulating layer from the backing sheet and applied to the carrier element, the carrier element being heat treated for the purpose of burning out the film and sintering on the insulating layer.
It is possible with the aid of such production methods for very small sensor structures to be applied simply and correctly even to angular structures of the carrier element.
In a refinement, before the application of the film layer, the insulating layer, a conductor track layer and, thereupon, a patterned resistive layer which has the strain-sensitive precision resistors and thick-film resistors of the electronic evaluation system are sequentially printed onto the backing sheet and dried, the film layer completely covering the arrangement of insulating layer, conductor track layer and patterned resistive layer, and this arrangement being removed from the backing sheet with the aid of the film layer and being placed on the carrier element such that the insulating layer makes direct contact with the carrier element.
The advantage of this method consists in that the entire sensor structure is positioned on the carrier element in one step.
In order to ensure the adhesion of this sensor structure to the carrier element, the carrier element is wetted with a primer before the insulating layer is placed on.
Particularly if the carrier element is the component which is to be mechanically loaded, the insulating layer is arranged directly on the component to be mechanically loaded owing to the elimination of an intermediate carrier. The mechanical load to be detected is tapped in this case directly from the component to be loaded without occurrence of signal corruptions caused by the intermediate carrier. The insulating layer and the component to be mechanically loaded are intimately interconnected by the subsequent heat treatment.
In another development, after the heat treatment of the insulating layer on the carrier element, the conductor track layer produced on a second backing sheet is peeled from this second backing sheet with the aid of the second film layer arranged over this conductor track layer, and positioned on the insulating layer and the carrier element is subsequently subjected to further heat treatment, and, after this heat treatment of the conductor track layer, the patterned resistive layer produced on a second backing sheet is applied to the conductor track layer by means of a third film layer covering this patterned resistive layer, and is likewise heat treated. Each layer can thus be produced individually and be sintered individually on the carrier element. This has the advantage, in particular for the patterned resistive layer, that ch
Mattmann Erich
Weber Klaus
Mannesmann VDO AG
Mayer Brown & Platt
Smith Sean
Young Lee
LandOfFree
Method for producing an electric resistor and a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing an electric resistor and a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing an electric resistor and a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2496448