A device which is suitable for applying a lacquer film to a disc-shaped registration carrier, as well as a method to be used therewith

Abstract: The present invention relates to a device and a method suitable for applying a lacquer film to a disc-shaped registration carrier (2), wherein atomized lacquer constituents are exhausted during the application of the liquid lacquer. The device is provided with a separator (12), in which the lacquer particles present in said atomized constituents are caught, wherein said separator (12) comprises a cyclone.

Description: The invention relates to a device for collecting excess atomized lacquer from an apparatus for applying a lacquer film to a disc-shaped registration carrier comprising at least one exhaust pipe in which an air stream containing excess atomized lacquer is withdrawn from an area adjacent to the registration carrier and sent to an interior of a cyclone, the cyclone comprising a container with a bottom, top and an interconnecting side wall that collectively define the interior therein, wherein the container is provided with an exhaust pipe in which the air stream containing excess atomized lacquer flows to direct the air stream into a circular flow pattern within the interior of the container, whereby the lacquer is collected and withdrawn from within the interior of the cyclone through a lacquer discharge channel. The invention furthermore relates to a method for applying a lacquer film to a disc-shaped registration carrier, wherein atomized lacquer constituents are exhausted during the application of the liquid lacquer to the disc-shaped registration carrier. U.S. 5,672,205 relates to a coating apparatus wherein in the resist application the resist solution portions scattered around from the wafer are collected in the cup, and sent as a waste solution from the drain opening at the bottom of the cup through the drain pipe to the tank. At the same time the air present in the cup is also discharged as a waste gas from the drain opening together with the waste solution. This means that the waste solution and the air are sent together from the cup to the tank in which the separation of the waste solution and the air (liquid-gas separation) is carried out. JP-10 004 050-A relates to a substrate processing apparatus wherein below a cup a stage is disposed with a mist separator inserted between said stage and an exhaust hole of the cup. JP-03 288 569-A relates to a treatment apparatus for controlling exhaust by providing a filter trapping the powder solidified and generated by a mist trap between the mist trap provided on the upstream side of an exhaust flow path of a gas-liquid mixture. JP 09 150 101-A relates to a substrate treating device wherein a resist is supplied to the surface of the substrate from a nozzle. A cup is arranged in proximity to this substrate so as to enclose its circumference wherein a mist capturing plate is disposed in the cup in the position where the mists collide against the spiral air flow, said mist capturing plate captures and recovers the mists within the cup. With a device known from EP-0 594 252 for applying a lacquer film to a disc-shaped registration carrier, such as CDs or CD recordables, a liquid lacquer is applied to the disc-shaped registration carrier whilst the disc-shaped registration carrier is being rotated. By rotating the disc-shaped registration carrier, the liquid lacquer being applied is spread uniformly over the surface of the disc-shaped registration carrier. In order to apply the thin lacquer film relatively quickly, the disc-shaped registration carrier is rotated at a relatively high rotational speed. As a result of the high rotational speed during the so-called spinning out of the lacquer film, air swirls are formed near the outer edge or near the circumference of the disc-shaped registration carrier. In combination with the spinning off of excess liquid lacquer from the disc-shaped registration carrier, this leads to the formation of a mist of small liquid particles. This mist is carried off by for example a downward air flow. So far the mist has been discharged into the environment together with the exhausted air, which is undesirable, however. In the first place, the fan or pump carrying out the exhaustion operation as well as the pipes are fouled by lacquer particles precipitating from the mist. Moreover, the emission of air containing lacquer particles is unacceptable for environmental reasons. The object of the invention is to provide a device wherein atomized constituents formed during the application of a lacquer film to a disc-shaped registration carrier are discharged in a relatively clean manner. The present invention is not restricted to any particular lacquer, i.e. a lacquer comprising pigments, dyes, a UV hardening lacquer etc. may be used in the present invention. This objective is accomplished with the device according to the invention in which device the exhaust pipe and the lacquer discharge channel are both located in the lower half of the container. Since the liquid lacquer particles are caught in said separator, said particles will not end up in the fan, the pump, the piping and the environment. The use of a cyclone makes it possible in a simple manner to obtain a separation between relatively heavy lacquer particles and the other atomized constituents. Said other atomized constituents substantially comprise air and possibly volatile lacquer constituents. Another embodiment of the device according to the invention is characterized in that said cyclone is connected to an air pipe from another process station, preferably a station in which a UV lamp is disposed. Said UV lamp is for example used in another station, where curing of the lacquer film that has been applied to the disc-shaped registration carrier takes place. The UV lamp generates heat, and in order to achieve a reliable operation it is desirable to cool said lamp. Exhaustion from the UV lamp not only provides a cooling effect, but also the ozone being formed is removed thereby. Thus, an efficient air control is realised by a combination of exhausting and subsequently supplying the air to the cyclone. Another embodiment of the device according to the invention is characterized in that said cyclone is provided with a container, two pipes arranged coaxially therein, wherein a gap is present between the ends of said two pipes, whilst a channel opens into a space present between said container and a pipe, whilst on the side remote from said container said channel opens near the circumference of a registration carrier to be provided with a lacquer film. Additional air is supplied via a first pipe, which air is discharged, together with the other atomized constituents, via the second pipe. As a result of the supply of air from the first pipe, a relatively good swirling air flow is formed in the cyclone. Preferably, air from another process station, preferably a station in which a UV lamp is disposed as-described before, is supplied through said first pipe. The invention will now be explained in more detail with reference to a drawing, wherein: Figure 1 is a cross-sectional view of a device for applying a lacquer film; Figure 2 is a cross-sectional view of a separator comprising a cyclone according to the invention; and Figure 3 is a cross-sectional view,. in the direction indicated by III-III, of the separator of Figure 2. Corresponding parts are indicated by the same numerals in the figures. Figure 1 shows a device 1 for applying a lacquer film to a disc-shaped registration carrier 2, which device 1 is provided with a cup-shaped container 3, in which a support 5 which is rotatable about a central axis 4 is disposed. Support 5 is driven in the direction indicated by arrow P1 by means of a motor 6. A lacquer supply channel 7 discharges into cup-shaped container 3, via which channel lacquer is applied to disc-shaped registration carrier 2. Cup-shaped container 3 is furthermore provided with one or more discharge pipes 23 for discharging excess lacquer in the direction indicated by arrow P4, and with a number of exhaust pipes 9 for exhausting atomized lacquer constituents. Said exhaust pipes 9 are preferably disposed at the position where air swirls form a mist 11 of small liquid particles, namely at the outer edge or near the circumference of the disc-shaped registration carrier 2. In a special embodiment of the device according to the present invention it is preferred to arrange exhaust pipe 9 round the entire circumference of disc-shaped registration carrier 2. Thus an annular exhaust pipe 9 is obtained, which is disposed near the outer edge 10. It is also possible, however, to arrange a number of exhaust pipes 9 in regularly spaced-apart relationship along outer edge 10. Before discussing the separator comprising a cyclone according to the present invention, the operation of device 1, which is known per se, will first be discussed in more detail. Support 5 and the disc-shaped registration carrier 2 present thereon are rotated at a relatively high speed of rotation in the direction indicated by arrow P1 by means of motor 6. Lacquer is applied to the disc-shaped registration carrier 2 from lacquer supply channel 7, near the centre of disc-shaped registration carrier 2, whereby the rotation of the disc-shaped registration carrier 2 will cause the lacquer to spread. Excess lacquer falls into cup-shaped container 3 near the outer edge 10 of disc-shaped registration carrier 2, and is discharged via one or more discharge pipes 23. As a result of said rotation, air swirls are formed near the outer edge 10 of disc-shaped registration carrier 2, which air swirls, together with the excess liquid lacquer, form a mist 11 of air and small liquid lacquer particles. Said mist 11 is exhausted through exhaust pipe 9 in the directions indicated by arrows P2. Figure 2 shows a separator comprising a cyclone 12 according to the invention, which is provided with a cylindrical container 13 and two pipes 14, 15 coaxially disposed therein. A gap 16 is present between the facing ends of pipes 14, 15. Container 13 is furthermore provided with an inlet 17, into which exhaust pipes 9 discharge. Pipes 9 preferably extend tangentially to the central axis 18 of container 13. Container 13 is furthermore provided with a lacquer discharge channel 19 near its bottom side. One end 20 of pipe 15 remote from pipe 14 is connected to a fan or pump (not shown) for drawing air through cyclone 12. One end 21 of pipe 14 remote from pipe 15 is connected to an air supply channel, which is for example connected to an air pipe which is used for cooling a UV lamp which is disposed nearby. The operation of cyclone 12 is as follows. Air is drawn from pipe 15, via end 20, by means of the fan, as a result of which air is drawn in from pipes 9 and 14. The air which is present in pipe 9, which air contains the atomized lacquer constituents, is introduced tangentially into the space 22 between container 13 and pipe 15 and will start to circulate in said space (refer in particular to Figure 3). Said pipe 14 preferably projects a small distance into container 13. When such a construction is used, a substantially undisturbed circulating air flow of the atomized constituents is generated between container 13 and pipes 14, 15, as a result of which no lacquer particles will be discharged in the direction indicated by arrow P3 via pipe 15. The relatively heavy lacquer particles are thereby moved towards the wall of container 13 and will slide along the wall of container 13 in the direction of lacquer discharge channel 19. The other atomized constituents, viz. the mist 11 from which the relatively heavy lacquer particles have been removed, are drawn in the direction of gap 16. The relatively lighter lacquer particles are carried along with the air flow to the top of container 13. As a result of the circulating air flow in container 13, the relatively lighter lacquer particles will agglomerate after some time, thus forming heavier lacquer particles, which are then moved to the wall of container 13, from where they will slide into lacquer discharge channel 19. Subsequently, the substantially clean air is carried off in the direction indicated by arrow P3 via pipe 15. The air being supplied in the direction indicated by arrow P4 via pipe 14 may have been utilized already, for example for cooling a UV lamp disposed in a station where curing of the lacquer applied to the registration carrier takes place. In this manner it is possible, using a single fan or pump, to create an air flow which can be utilized for cooling the UV lamp, for exhausting atomized constituents as well as for separating lacquer particles from the atomized constituents. The magnitude of the air flow and the degree of circulation of the atomized constituents can be influenced by changing the dimension of gap 16.

Claims: A device for collecting excess atomized lacquer from an apparatus (1) for applying a lacquer film to a disc-shaped registration carrier (2) comprising at least one exhaust pipe (9) in which an air stream containing excess atomized lacquer is withdrawn from an area adjacent to the registration carrier (2) and sent to an interior of a cyclone (12), the cyclone (12) comprising a container (13) with a bottom, top and an interconnecting side wall that collectively define the interior therein, wherein the container (13) is provided with an exhaust pipe (9) in which the air stream containing excess atomized lacquer flows to direct the air stream into a circular flow pattern within the interior of the container (13), whereby the lacquer is collected and withdrawn from within the interior of the cyclone (12) through a lacquer discharge channel (19), characterized in that the exhaust pipe (9) and the lacquer discharge channel (19) are both located in the lower half of the container (13). A device according to claim 1, characterized in that said cyclone (12) is provided with a pipe (14) for supplying air to the container (13). A device according to claims 1 - 2, characterized in that said cyclone (12) comprises a first pipe (14) and a second pipe (15) arranged coaxially within the container (13), wherein the first pipe (14) supplies air to the cyclone (12), wherein a gap (16) is present between the opposing ends of said two pipes (14,15), wherein the second pipe (15) draws air through the cyclone (12). A device according to claims 2 and 3, characterized in that the second pipe (15) is connected to a pump, whilst the first pipe (14) comprises the pipe for supplying air. A device according to claims 2 - 4, characterized in that the first pipe (14) for supplying air originates at a station in which a UV lamp is disposed. A device according to claim 3, characterized in that the gap (16) present between the ends of the two pipes (14,15) is positioned substantially in the centre of said container (13). A method for collecting excess atomized lacquer from an apparatus (1) for applying a lacquer film to a disc-shaped registration carrier (2) comprising: withdrawing air containing excess atomized lacquer from an area adjacent to the registration carrier (2) through at least one conduit (9); transporting the withdrawn air containing excess atomized lacquer into an interior of a cyclone (12) having a container (13) with a bottom, top and interconnecting side wall that collectively define the interior therein, where the exhaust pipe (9) and the lacquer discharge channel (19) are both located in the lower half of the container (13); directing the withdrawn air containing excess atomized lacquer into a circular flow pattern; collecting a first a volume of heavier particles at the side wall and a second volume of lighter particles near the top; and discharging the collected volumes in the lower half of the cyclone (12). A method according to claim 7, characterized in that air from a station in which a UV lamp is disposed is drawn through said cyclone (12), which air absorbs said atomized constituents.

Inventors: VAN DER BLIJ FREDRIK WILHELM, VAN DER HORST GIJSBERTUS NICOL, VAN DER BLIJ, FREDRIK WILHELM, VAN DER HORST, GIJSBERTUS NICOLAAS MARIA
Applicants: OTB GROUP BV, OTB GROUP B.V.
Application year: 1999
Main classification: B05C11
IPC codes: B04C5, G11B7, B05C11, B04C7