Methods for measuring the sorbate content of substrates

US6178812A · kind A · utility

Assignee

• LPKF LASER & ELECTRONICS AG · DE

Inventors

• Joerg Kickelhain · Neustadt, DE
• Olaf Schulz · Berlin, DE
• Frank Imkenberg · Hannover, DE

Key dates

• Filing date: Aug 13, 1999
• Grant date: Jan 30, 2001
• Expiry date: Aug 13, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N33/246
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to methods for measuring the sorbate content in substrates, using a sensor with a measuring chamber. Said chamber contains a support medium whose partial pressure of sorbate is determined in order to determine the sorbate content of the substrate. According to the first method, the temperature of the support medium is varied up to a value at which the partial pressure of sorbate in the measuring chamber no longer varies with the temperature of the support medium, and slightly over this value. This partial pressure of sorbate is then used to determine the sorbate content of the substrate. According to the second method, the temperature of the support medium is kept essentially constant and the speed at which the partial pressure of sorbate of the support medium approaches the stable end value is determined. The sorbate content of the substrate is then determined taking into account the known dependency relationship between said speed and the vapor or solution partial pressure in the substrate. The two methods provide a way of measuring relatively high humidity contents of substrates based on the determination of the equilibrium moisture content.