Sealant dispenser and control method thereof

Abstract

Disclosed is a sealant dispenser for more precisely dispensing a sealant onto a substrate, and a control method thereof. The sealant dispenser includes a stage on which a substrate is mounted; a nozzle for dispensing a sealant while making a relative motion with the substrate; a syringe coupled to the nozzle, for storing the sealant; and a distance sensor installed on both sides of a lower portion of the syringe, for measuring a vertical distance between a principal plane of the substrate and an outlet of the nozzle. According to the principles of the present invention, because the nozzle and the syringe have substantially the same central axis, the response speed of the sealant to be dispensed is increased and the start point and the end point of paste pattern are more precisely dispensed. Also, by minimizing the distance between the nozzle and a measuring point provided by the distance sensor, it becomes possible to dispense the sealant at higher precision.

Description

RELATED APPLICATION[0001]This application is a divisional of application Ser. No. 11 / 125,528 filed May 10, 2005, which claims priority to Korean Patent Application No. 10-2004-0033395 filed May 12, 2004, the contents of both are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates in general to a sealant dispenser, and more specifically, to a sealant dispenser for more precisely applying (or dispensing) a sealant onto a substrate, and a control method thereof.[0004]2. Background of the Related Art[0005]In general, liquid crystal display (LCD) is lighter and smaller by volume than a traditional image display device using cathode-ray tube (CRT). Therefore, making great strides in recent years, LCD has been widely applied in many display devices, such as computer monitors and TVs.[0006]In case of the LCD, there is a certain space between an upper substrate and a lower substrate, and the space is filled with liqui...

AI Technical Summary

Benefits of technology

The present invention is a sealant dispenser and control method that solves problems in the related art. The invention features a low pressure for dispensing sealant, a high precision in dispensing, and an accurate control over the dispensing position and amount. The invention includes a stage for mounting a substrate, a nozzle for dispensing sealant, a distance sensor for measuring the vertical distance between the substrate and the nozzle, and a position detecting sensor for detecting the horizontal position of the nozzle. The invention also includes an adjusting part for adjusting the position of the syringe storing the sealant. The invention provides a sealant dispenser with improved precision and control over the dispensing position and amount.

Problems solved by technology

This is because if the cell gap is not uniform or if liquid crystal is applied too much or insufficiently, the screen uniformity over the entire screen of an LCD will be deteriorated.

Firstly, since the nozzle and the syringe are spaced a designated distance apart, the flow path of the sealant is bent in “L” shape. In detail, the distance sensor and the syringe of the related sealant dispenser are separately installed in the head unit while maintaining a designated distance from each other. This is why the flow path of the sealant has an “L” shape.

In that light, the related art dispenser requires a high pressure for discharging the sealant, and the usage of a highly viscous sealant was limited.

Secondly, according to the related art sealant dispenser, the nozzle is installed on the lower portion of the bracket, so that there is a great distance between the position on the substrate where the sealant is discharged and the position on the substrate where a laser beam is reflected.

Therefore, the distance sensor cannot get an accurate a vertical distance from the point to which the sealant is actually discharged to the nozzle.

Thirdly, since the flow path of the sealant in the related art sealant dispenser is in “L” shape, the sealant is relatively slowly discharged.

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