WO1998056548A1

WO1998056548A1 - Method and apparatus for separating el lamps from panels

Info

Publication number: WO1998056548A1
Application number: PCT/US1998/011112
Authority: WO
Inventors: Ralph Mcguigan
Original assignee: Durel Corporation
Priority date: 1997-06-12
Filing date: 1998-06-04
Publication date: 1998-12-17

Abstract

Lamps are blanked by perforating an EL panel (10) in the outlines of lamps, passing the panel between a first set of rollers (24) operating at a first rate of travel and then passing the panel between a second set of rollers (23) operating at a second rate of travel while a portion of the panel remains between the first set of rollers. The second rate is greater than the first rate and the second set of rollers gently pulls the lamps from the panel. If the panel is blanked into rows and columns of lamps, a second separator (33, 35) is provided, orthogonal to the first.

Description

METHOD AND APPARATUS FOR SEPARATING EL LAMPS FROM PANELS

BACKGROUND OF THE INVENTION

This invention relates to the manufacture of electroluminescent (EL) panels and, in particular to a device for separating blanks or pre-punched lamps from a panel .

As used herein, an EL "panel" is a single sheet including one or more luminous areas, wherein each luminous area is an EL "lamp." An EL lamp is essentially a capacitor having a dielectric layer between two conductive electrodes, one of which is transparent. The dielectric layer includes a phosphor powder or there is a separate layer of phosphor powder adjacent the dielectric layer. The phosphor powder radiates light in the presence of a strong electric field, using very little current.

A modern (post-1980) EL panel includes a front electrode that is typically a thin, transparent layer of indium tin oxide or indium oxide on a substrate such as a sheet of polyester or polycarbonate, which provides mechanical support for the other layers . Such coated sheets are commercially available. The panel is typically made by screen printing a phosphor layer on the front electrode, then screen printing a dielectric layer on the phosphor layer, and then screen printing a rear electrode on the dielectric layer.

Individual lamps are cut or are punched from a panel using a die in what is known as a "blanking" operation and the lamps are then assembled into other devices, e.g. for backlighting the dial of a wristwatch. The blanking operation is manually intensive, expensive, and can cause some good lamps to fail because of poor handling. A partial solution to the problem is to perforate the outline of the blanks rather than cutting through the panel . This enables lamps to be tested in a panel and to be handled together as a panel. Lamp separation entails gently tugging the lamps from the panel and supplying the lamps to the next work station. A problem with this approach is that it does not eliminate manually handling the lamps. Frequently, lamps are rolled or curled by the person trying to separate the lamps from the panel , which stresses the layers in the lamps and often leads to lamp failure. Further, a person cannot consistently apply the same force to the lamps for separating the lamps, leading to further damage to the lamps when excessive force is applied.

In view of the foregoing, it is therefore an object of the invention to automate the separation of EL lamps from a panel.

Another object of the invention is to provide a mechanism for gently separating EL lamps from a panel .

A further object of the invention is to increase the number of good lamps per EL panel . Another object of the invention is to provide an apparatus for applying a consistent force to EL lamps for separating the lamps from a panel .

SUMMARY OF THE INVENTION

The foregoing objects are achieved in this invention in which lamps are blanked by perforating an EL panel in the outlines of lamps, passing the panel between a first set of rollers operating at a first rate of travel and then passing the panel between a second set of rollers operating at a second rate of travel while a portion of the panel remains between the first set of rollers. The second rate is greater than the first rate and the second set of rollers gently pulls the lamps from the panel. If the panel is blanked into rows and columns of lamps, a second separator is provided, orthogonal to the first. BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention can be obtained by considering the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view of an EL panel after blanking to produce perforations along the separation lines of the panel ;

FIG. 2 is a top view of apparatus for separating lamps from an EL panel in accordance with the invention;

FIG. 3 is a top view of an alternative embodiment of apparatus for separating lamps from an EL panel;

FIG. 4 is a side view of the apparatus illustrated in FIG. 3; and FIG. 5 is a side view of an alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an EL panel in which a plurality of lamps are defined by perforations. In panel 10, a plurality of lamps, such as lamps 12 and 14, have been blanked in rows and columns by perforating an outline of each lamp. Although adjoining rows and adjoining columns share a common perforation, this is not necessary in order to obtain the advantages of the invention.

In accordance with the invention, EL panel 10 is fed in the direction indicated by arrow 15 to a separator having two consecutive pairs of rollers operating at slightly different speeds for separating the lamps. The lamps separate from the panel along the perforations . The lamps in the first column, i.e. the column containing lamp 12, are separated from panel 10 and then subsequent columns are separated. Each column of EL lamps is then fed to another device for separating the lamps within a column. FIG. 2 illustrates the preferred embodiment of the separator constructed in accordance with the invention. Separator 20 includes tray 21 for receiving lamp panel 10. Tray 21 is fixed and has a low friction surface or has a moving belt for conveying panel 10 to cylindrical rollers 23 and 24. The left-hand side of tray 21 ends in rails 28 and 29 that define opening 31 for receiving the detached columns of lamps .

A second pair of cylindrical rollers (not shown) underneath rollers 23 and 24 engage rollers 23 and 24 to separate the columns from panel 10 as the panel passes between the rollers. As illustrated in FIG. 2, roller 24 is slightly larger in diameter than roller 23. The spacing of the rollers is adjustable. In FIG. 2, roller 23, and the roller underneath, are movable relative to roller 24 to accommodate lamps of different sizes.

The rollers are rotated at the same rate, thereby causing the surface speed of roller 23 to be greater than the surface speed of roller 24. When column 26 engages roller 23, and the roller underneath, the column is gently pulled from the adjoining column and out of panel 10. The empty panel is supported at the edges by rails 28 and 29.

After separation, column 26 falls between rails 28 and 29 onto belt 31 for further separation by rollers 33 and 35. Rollers 33 and 35 and a second pair of rollers (not shown) underneath rollers 33 and 35 engage the lamps to separate the lamps as the column passes between the rollers. The spacing of these rollers is also adjustable. Roller 35, and the roller underneath, are movable relative to roller 33 to accommodate lamps of different sizes.

Roller 35 is larger in diameter than roller 33 and rotates at the same number of revolutions per minute as roller 33, giving roller 35 a greater surface speed than roller 33 and providing a gentle tug on the lamps to separate the lamps along the perforations between the lamps . The apparatus of FIG. 2 thus provides pairs of consecutive rollers operating at different speeds to separate EL lamps from a panel. A first separator feeds a second separator operating in a direction orthogonal to the direction of the first separator, thereby completely separating all lamps from a panel without manual intervention. The perforations need not be parallel to the rollers for separation to occur, as shown by the separation of a column of lamps from a panel. Preferably, rollers 23 and 24 are parallel and do not apply sufficient force for separating lamps within a column. A second separator is provided for separating lamps within a column.

FIG. 3 illustrates a separator constructed in accordance with an alternative embodiment of the invention in which each roller includes a plurality of wheels turned by a common shaft. In FIG. 3, rollers 41 and 42 have the same diameter and are driven by pulleys 45 and 46 in which pulley 45 is smaller than pulley 46. The result is that roller 41 rotates slightly faster than roller 42, thereby separating the lamps from each other. The difference in the surface speed of the rollers is not great. In a preferred embodiment of the invention, the downstream rollers operate at approximately 105% of the speed of the upstream rollers. The difference is speed depends, in part, upon the frailty of the lamps and the degree of perforation. A twenty percent difference in speed is likely to be excessive under all circumstances.

The spacing of the rollers is adjustable and is determined by the size of the lamps to be separated. In particular, the spacing of the rollers is determined by the longitudinal dimension of the lamps; that is, the dimension of the lamps along the line of travel. The rollers are separated by a distance s and this distance is slightly greater than longitudinal dimension d, e.g., approximately 0.05 inches greater. The rollers should not be separated less than d because this would cause the rollers to pull or stress the lamps .

In accordance with another aspect of the invention, the housings for mounting the rollers preferably includes indicia for indicating the center to center spacing of the rollers. Indicia 38 and 39 are on the centerlines of the rollers and are separated a distance s or, preferably, by a distance equal to s - , where is equal to 0.05". Thus, by separating the rollers according to the indicia, the slight extra space is always included for assuring that both sets of rollers are not on the same lamp at the same time.

In FIG. 4, panel 10 is fed to a first pair of pinch rollers, 51 and 52, by belt 53. Preferably the surface speeds of rollers 51 and 52 match the surface speed of belt 53. Belt 53 is driven by a suitable source (not shown) . Pinch rollers 51 and 52 feed panel 10 to a second pair of pinch rollers, 55 and 56, that operate at slightly higher surface speed than pinch rollers 51 and 52. Pinch rollers 55 and 56 feed the separated lamps to belt 58 for transport to further assembly apparatus (not shown) . Belt 58 preferably operates at the same surface speed as pinch rollers 55 and 56.

In FIG. 5, a belt encircles one of the rollers in each pair of rollers. Roller 51 and belt 61 feed a strip of lamps to roller 55 and belt 62. Roller 51 and belt 61 operate at the same surface speed, as do roller 55 and belt 62. In accordance with the invention, roller 51 has a lower surface speed than roller 55, thereby causing the lamps to separate as a strip of lamps is feed from one belt to the other.

The invention thus provides a suitable means for gently separating individual lamps from a panel automatically and without manual handling. The panel, and separated lamps, are essentially always planar, thereby minimizing damage to the lamps due to flexing. The apparatus applies a consistent force to separate the lamps, further minimizing damage to the lamps.

Having thus described the invention it will be apparent to those skilled in the art that various modifications can be made within the scope of the invention. For example, a belt and roller can be used instead of a pair of rollers for separating lamps in accordance with the invention. The surface speed of the rollers is not limited by the invention because the invention is concerned only with the difference in the speed of the consecutive rollers. In one embodiment of the invention, a surface speed of 2-5 feet per second was adequate. The rollers touch but do not pinch the lamp between the rollers, which would damage the lamps. The rollers are preferably slightly resilient, having a rubber or vinyl coating. The perforation can be in any form suitable for the materials from which the panel is made. For example, a series of slits or a plurality of laser- drilled holes can be used as perforations for defining each lamp or a die can be modified by a toolmaker by a process known as "nicking" to provide the perforations. Alternatively, one can rely on the slight gap between blades at each corner of the lamps to leave a small bridge that holds the lamps in a panel .

Claims

What is claimed as the invention is:

1. A method for separating EL lamps from a perforated panel, said method comprising the steps of: passing the panel between a first set of rollers operating at a first rate of travel; passing the panel between a second set of rollers operating at a second rate of travel while a portion of the panel remains between the first set of rollers; wherein the second rate is greater than the first rate.

2. The method as set forth in claim 1 and further including the steps of: passing the panel between a third set of rollers operating at a third rate of travel; passing the panel between a fourth set of rollers operating at a fourth rate of travel while a portion of the panel remains between the third set of rollers; wherein the fourth rate is greater than the third rate and the third and fourth sets of rollers are orthogonal to the first set of rollers, thereby completely separating the lamps from the panel .

3. Apparatus for separating EL lamps from a panel, said apparatus comprising: a first pair of rollers rotating at a first surface speed; a second pair of rollers rotating at a second surface speed; wherein the first surface speed is less than the second surface speed; the pairs of rollers move the panel in a first direction; and the first pair of rollers is separated from the second pair of rollers by a distance greater than the longest dimension of a lamp in said first direction.

4. The apparatus as set forth in claim 3 wherein said first pair of rollers have the same diameter as the second pair of rollers.

5. The apparatus as set forth in claim 3 wherein said first pair of rollers rotate at the same number of revolutions per second as the second pair of rollers.

6. The apparatus as set forth in claim 3 wherein the rollers in at least one pair of rollers is cylindrical.

7. The apparatus as set forth in claim 3 wherein the rollers in at least one pair of rollers each include a plurality of wheels turned by a common shaft.

8. The apparatus as set forth in claim 3 and further comprising a pair of belts, wherein a belt encircles one roller in each pair of rollers.