# US 2014/0360281 A1 · Stress measurement sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360281 A1 - Document ID: US20140360281A1 - Status: Published application - Kind: A1 - Application number: 14/245,335 - Filed: 2014-04-04 - Published: 2014-12-11 - Earliest claimed: 2013-04-08 - Assignees: Pro-Micron GmbH; Horst Siedle GmbH & Co. KG - Inventors: Christian Helbig; Sebastian Lotz - Web page: https://patentgrep.com/patent/US20140360281A1 ## CPC - G01L 1/165: {with acoustic surface waves} - G01B 7/00: Measuring arrangements characterised by the use of electric or magnetic techniques - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - G01L 9/0042: {Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms (details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively)} - H03H 2003/028: {for obtaining desired values of other parameters} - Y10T 29/42: Piezoelectric device making - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A stress measurement sensor provided with a sensor element that operates according to the SAW principle, comprising a base composed of a first material and the sensor element, which is fixed to the base with a joining material, is to be developed such that it can also be used at higher temperatures and has improved measurement properties. In addition, it is suggested that the joining material be a glass solder. ## Claims ### Claim 1 A stress measurement sensor provided with a sensor element that operates according to the SAW principle, comprising a base composed of a first material, and the sensor element, which is fixed to the base with a joining material, wherein the joining material is a glass solder. ### Claim 2 (depends on 1) The stress measurement sensor according to claim 1, wherein the material combination comprising the first material of the base, the glass solder and a carrier crystal of the sensor element is selected in such a way that the following relationships apply to the thermal expansion coefficients of the materials involved, namely the thermal expansion coefficient of the first material of the base CTEbase, the thermal expansion coefficient of the glass solder CTEglass solder and the thermal expansion coefficients of the carrier crystal of the sensor element that operates according to the SAW principle CTESAW: CTESAW−3≦CTEbase≦CTESAW+7; i. CTEglass solder≦CTEbase−2; ii. wherein the unit for the values for the thermal expansion coefficients is given in ppm/K. ### Claim 3 (depends on 2) The stress measurement sensor according to claim 2, wherein the following relationship applies to the thermal expansion coefficients of the first material of the base and the thermal expansion coefficients of the carrier crystal of the sensor element that operates according to the SAW principle CTESAW: CTESAW−1≦CTEbase≦CTESAW+5; i. wherein the unit for the values for the thermal expansion coefficients is given in ppm/K. ### Claim 4 (depends on 2) The stress measurement sensor according to claim 2, wherein the following relationship applies to the thermal expansion coefficients of the first material of the base, CTEbase, and the thermal expansion coefficients of the glass solder, CTEglass solder: CTEglass solder≦CTEbase−4. ii. ### Claim 5 (depends on 1) The stress measurement sensor according to claim 1, wherein the first material of the base is a steel. ### Claim 6 (depends on 5) The stress measurement sensor according to claim 5, wherein the first material of the base is an austenitic steel or a duplex steel. ### Claim 7 A method for forming a stress measurement sensor having a sensor element that operates according to the SAW principle, which method comprises the following steps: a. provision of a base composed of a base material; b. provision of a sensor element operating according to the SAW principle, and having a carrier crystal; c. provision of a glass solder; d. connecting the base to the carrier crystal by means of interlayering, fusing and subsequent solidifying of the glass solder. ### Claim 8 (depends on 7) The method according to claim 7, wherein the combination comprising the base material, sensor element with carrier crystal and glass solder is selected in such a way that the following relationships apply to the thermal expansion coefficients of these materials, thus the thermal expansion coefficients of the base material CTEbase, the thermal expansion coefficients of the carrier crystal CTESAW and the thermal expansion coefficients of the glass solder CTEglass solder: CTESAW−3≦CTEbase≦CTESAW+7; i. CTEglass solder≦CTEbase−2; ii. wherein the unit for the values for the thermal expansion coefficients is given in ppm/K. ### Claim 9 (depends on 8) The method according to claim 8, wherein the combination comprising the base material, sensor element with carrier crystal and glass solder is selected in such a way that the following relationship is maintained for the thermal expansion coefficients of the base material CTEbase and the thermal expansion coefficients of the carrier crystal of the sensor element that operates according to the SAW principle CTESAW: CTESAW−1≦CTEbase≦CTESAW+5; i. wherein the unit for the values for the thermal expansion coefficients is given in ppm/K. ### Claim 10 (depends on 8) The method according to claim 8, wherein the combination comprising the base material, sensor element with carrier crystal, and glass solder is selected in such a way that the following relationship is maintained for the thermal expansion coefficients CTEbase of the base material and CTEglass solder of the glass solder: CTEglass solder≦CTEbase−4. ii. ### Claim 11 (depends on 7) The method according to claim 7, wherein a steel is selected for the base material. ### Claim 12 (depends on 7) The method according to claim 7, wherein a maximum process temperature is selected for the fusing of the glass solder that is ≦500° C. ### Claim 13 (depends on 4) The stress measurement sensor according to claim 4, wherein the following relationship applies to the thermal expansion coefficients of the first material of the base, CTEbase, and the thermal expansion coefficients of the glass solder, CTEglass solder: CTEglass solder≦CTEbase−8. ii. ### Claim 14 (depends on 10) The method according to claim 10, wherein the following relationship is maintained for the thermal expansion coefficients CTEbase of the base material and CTEglass solder of the glass solder: CTEglass solder≦CTEbase−8. ii. ### Claim 15 (depends on 11) The method according to claim 11, wherein the steel is an austenitic steel or a duplex steel. ### Claim 16 (depends on 12) The method according to claim 12, wherein the maximum process temperature is in from about 300° C. up to about 500° C.