Precision dispensing process control
US6061608A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 2, 1997 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | Sep 2, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An apparatus and method that precisely controls the amount of liquid dispensed from dispensing apparatus onto an article. The present invention controls the weight of the dispensed liquid by using a force transducer that precisely weighs the article and dispensed liquid during the dispensing process. This weight value is input to a computer controller of an automatic dispenser that embodies a computer program that controls a liquid dispensing pump. Liquid is dispensed until the desired weight of liquid that is to be dispensed is reached, defined by an upper limit in the program. The flow of dispensed liquid is reduced when the weight limit is approached, and is stopped when the weight limit is reached. Thus, in the present invention, the weight (or volume) of the dispensed liquid is controlled in real time during the dispensing process. Closed loop control of the dispensing pump using liquid weight as the controlling variable improves the volumetric accuracy and repeatability of the dispensing process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.