JP2011119384A - Depressurized drying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a depressurized drying apparatus capable of solving problems in a conventional depressurized drying apparatus, providing a stable upper lid sealing operation for a long period of time, and causing no large damage to the apparatus at the occurrence of an abnormality. <P>SOLUTION: A depressurized drying apparatus 1 used for removing a solvent in a coated film coated on a substrate includes a vacuum vessel having a body 2 and an upper lid 3, an upper lid opening/closing mechanism for opening and closing the vacuum vessel by vertically moving the upper lid, an exhausting device exhausting air from the vacuum vessel, a carrying mechanism carrying the substrate into the vacuum vessel, and a substrate holding mechanism holding the substrate in the vacuum vessel. The upper lid opening/closing mechanism is driven by a servo motor 5 and has a drive torque detection mechanism in a drive system. The servo motor stops at the time of preset closing torque value detection by the drive torque detection mechanism to close the upper lid. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  TECHNICAL FIELD The present invention relates to a drying apparatus for removing volatile components in a coating film applied on a substrate, and in particular, a reduced-pressure drying apparatus used for drying a color resist coating film for a color filter applied on a glass substrate. About.

  As color filters used in the liquid crystal display, red (R: Red), green (G: Green), and blue (B) corresponding to the three primary colors of light on the glass substrate 30, as shown in FIGS. In general, a pixel in which colored pixels 31, 32, and 33 formed by using three color resists (Blue) are regularly arranged is used.

  As a method for forming the colored pixels, a color resist is applied on the glass substrate 30 and is pre-dried, then exposed through a photomask having a predetermined pattern, developed and patterned, and finally after-sales. A series of steps of baking and completely curing the pixels is repeated for each color. In actual products, elements such as black matrix 34 and photo spacers are added in addition to RGB three colors, so resist coating, drying, exposure, development, curing treatment, etc. on one glass substrate This process is repeated many times.

  As a method for drying the resist coated on the glass substrate, a pre-baking process by low-temperature heating or a vacuum drying apparatus without heating is used in order to prevent hot fogging. The vacuum drying apparatus efficiently removes the solvent in the coating film by placing the substrate in a vacuum container, exhausting the air in the container and reducing the pressure, but this process is a batch process. Therefore, in a continuous processing line, it is necessary to perform a series of operations such as transferring a substrate, opening / closing a vacuum vessel, exhausting, releasing atmospheric pressure, etc. without waste.

  As an operation of the reduced pressure drying apparatus, the substrate is transferred into the vacuum container, and after the transfer unit is retracted, the upper lid of the vacuum container is closed and the exhaust process is started. The vacuum vessel is evacuated by a vacuum pump. During processing, the degree of vacuum in the apparatus is monitored by a measuring instrument, and when a predetermined set pressure is reached, exhaust is terminated, the pressure is released to atmospheric pressure, the upper lid is opened, the substrate is unloaded, and the processing is completed ( Patent Document 1).

  Conventionally, in order to quickly and accurately open and close the upper cover of the vacuum vessel, the upper cover is opened and closed using a servo motor, and the closing position of the upper cover is controlled by counting pulses that drive the servo motor.

JP 2006-19472 A

  In order to maintain the degree of vacuum in the vacuum drying apparatus, a packing is used between the upper cover of the vacuum vessel and the main body of the apparatus, which is in contact with the upper cover. If it comes to the end, a leak will occur, the degree of vacuum will not increase easily, and the processing time will increase. Leakage can be prevented by increasing the pushing amount of the upper lid by the amount of packing, but if the upper lid closing position is set by the pulse counter, the upper lid will always stop at the same position, so that leakage will occur. Happens. In practice, it is difficult to always set the setting value of the pulse counter optimally in anticipation of the sag of the packing.

  Another problem is that if the transport unit is not completely retracted for some reason, the transport unit may be destroyed if the upper lid is unconditionally lowered according to the set value of the counter. there were.

  The problem to be solved by the present invention is to solve these problems in the conventional vacuum drying apparatus, to realize a stable upper lid sealing operation over a long period of time, and to cause no significant damage to the apparatus even when an abnormality occurs. We propose a vacuum drying device that only requires

  As a means for solving the above-mentioned problems, the invention described in claim 1 is a vacuum drying apparatus used for removing a solvent in a coating film coated on a substrate, and is a vacuum comprising a main body and an upper lid. There is a container, an upper lid opening / closing mechanism that moves the upper lid up and down to open and close the vacuum container, an exhaust device that exhausts air in the vacuum container, a transport mechanism that transports the substrate into the vacuum container, and a vacuum container. The upper lid opening / closing mechanism is driven by a servo motor, and has a drive torque detection mechanism in the drive system, the servo motor having a preset closing torque value, The vacuum drying apparatus is characterized in that it stops when the drive torque detection mechanism detects and the upper lid closes.

  The invention described in claim 2 is the vacuum drying apparatus according to claim 1, wherein the drive torque detection mechanism is built in the servo motor.

  According to a third aspect of the present invention, the drive torque detecting mechanism can set an emergency stop torque value smaller than this in addition to the closing torque value, and the upper lid starts to descend from the top dead center. In the interval from before the upper lid closing position to the upper lid closing interval provided between the bottom dead center, the servo motor stops when the drive torque detection mechanism detects the emergency stop torque value, and the upper lid is closed. 3. The reduced-pressure drying apparatus according to claim 1, wherein the servo motor is stopped when the drive torque detection mechanism detects the closing torque value in the section. 4.

  In the vacuum drying apparatus according to the present invention, the upper lid opening / closing mechanism is driven by a servo motor, a drive torque detection mechanism is provided in the drive system, and when the drive torque detection mechanism detects a preset closing torque value, the servo motor Since the upper lid is closed and the upper lid of the vacuum vessel is closed, the upper lid is surely sealed even when the packing of the vacuum vessel is sunk, and there is no possibility that a vacuum leak will occur. Therefore, the problem that the processing time becomes longer than necessary due to a vacuum leak is solved.

  When the drive torque detection mechanism is built in the servo motor, the mechanism of the entire apparatus is simplified, resulting in a reduction in the cost of the apparatus and a reduction in failure.

  In addition, the detection of the closing torque value is effective when the upper lid exists in the upper lid closing section provided between the position before the upper lid closing position and the bottom dead center, and before the upper lid reaches the upper lid closing section, In the case where the upper lid has a mechanism that stops at an emergency stop torque value smaller than the closing torque value, even if the transport mechanism or the like interferes with the descending upper lid due to some trouble, for example, the driving torque The servo motor can be stopped by detecting this from a slight change in the motor, and can function as a safety device for minimizing damage to the device.

It is the perspective view which showed typically the structure of the vacuum dryer concerning this invention. It is the cross-sectional schematic diagram which showed the A-A 'cross section of FIG. It is the graph which showed the relationship between the position of the vacuum vessel upper cover in the normal state of the vacuum drying apparatus which concerns on this invention, and a drive shaft torque. It is the graph which showed the relationship between the position of a vacuum vessel upper cover, and drive shaft torque when the contact accident generate | occur | produced in the reduced pressure drying apparatus which concerns on this invention. It is a plane schematic diagram of the color filter for liquid crystal displays. FIG. 6 is a schematic cross-sectional view showing the X-X ′ cross section of FIG. 5.

Hereinafter, a vacuum drying apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view schematically showing the structure of a vacuum drying apparatus according to the present invention. FIG. 2 is a schematic cross-sectional view showing the AA ′ cross section of FIG.
The reduced-pressure drying apparatus 1 according to the present invention is a reduced-pressure drying apparatus used for removing a solvent in a coating film applied on a substrate 30, and is a vacuum composed of a vacuum container body 2 and a bowl-shaped vacuum container upper lid 3. A container, an upper lid opening / closing mechanism 4 that opens and closes the vacuum container by moving the upper lid 3 up and down, an exhaust device that exhausts air in the vacuum container, a transport mechanism 9 that transports the substrate into the vacuum container, and a vacuum container The upper lid opening / closing mechanism 4 is driven by a servo motor 5 and has a drive torque detection mechanism in the drive system, the servo motor 5 being set in advance. The reduced-pressure drying apparatus is characterized in that when the drive torque detection mechanism detects the closed torque value, the upper lid 3 is closed.

  In FIGS. 1 and 2, only the structure of the apparatus necessary for the present invention is schematically shown, and therefore, the basic portion, the control apparatus, the transport mechanism, the positioning apparatus, and the like that are present in the actual apparatus are omitted.

  1 and 2, only the exhaust pipe 6 is shown as an exhaust device, but the actual exhaust device includes a vacuum pump, a reserve tank, a valve, piping, a control device, and the like. As the vacuum pump, since a solvent vapor is present in the exhaust, it is preferable to use a dry pump that does not use oil. Furthermore, when a high vacuum is required, a mechanical booster pump or the like is used in combination. The degree of vacuum in the vacuum vessel is constantly monitored by the vacuum gauge 8.

  The upper lid opening / closing mechanism 4 is not particularly limited, but is preferably a mechanism with less dusting properties in consideration of use in a clean room. Moreover, it is preferable that the upper lid can be opened and closed quickly. From such a viewpoint, a mechanical drive system using a servo motor is a preferable mechanism. As means for converting the rotational movement of the servo motor into the vertical movement of the upper lid, there are a rack / pinion system, a system using a chain and a sprocket, or a method using a screw shaft. In FIG. 1, the upper lid 3 is held by four shafts, and each shaft constitutes an upper lid opening / closing mechanism 4 having a servo motor.

  As a drive torque detection mechanism installed in the drive system of the upper lid opening / closing mechanism 4, an independent torque detector may be used, or when the servo motor itself has a built-in torque detection function, this is used. May be. As a servo motor with a built-in torque detection function, a commercially available motor with a torque limiter can be used. As the torque detection mechanism, a mechanism capable of setting a torque set value and further capable of setting several stages of torque values is desirable. For example, if a two-stage torque value can be set, the tightening torque value of the upper lid 3 and the emergency stop torque value when an abnormality occurs can be set separately.

A packing 7 is provided between the main body 2 and the upper lid 3 of the vacuum container. The upper lid 3 moves on the main body 2 so that the upper lid 3 is covered with the substrate and the substrate is placed in the space of the upper lid 3. This prevents the leakage of vacuum inside the vacuum vessel when the vacuum vessel is closed. As the packing 7, a low-volatility stick-shaped rubber is used, but if it is frequently used for a long period of time, it gradually wears out and wears down. When the packing sags, the position where the lowered upper lid 3 contacts is shifted downward. At this time, if the closing position of the top lid 3 is simply determined by the number of pulses from the start position of the servo motor, it will always stop at the same position. When pulling starts, the vacuum leaks and the degree of vacuum does not increase easily. The degree of vacuum is measured by a vacuum gauge 8.

FIG. 3 is a graph showing the relationship between the position of the upper lid of the vacuum vessel and the drive shaft torque in the normal state of the vacuum drying apparatus according to the present invention.
The upper lid descends from the top dead center along the upper lid moving direction 20. The drive shaft torque of the upper lid opening / closing mechanism when the upper lid descends is substantially constant. When the upper lid comes into contact with the packing, the drive shaft torque rapidly increases. When the drive shaft torque reaches a preset closing torque set value, the drive torque detection mechanism detects this, stops the servo motor, and starts evacuating the vacuum vessel.

  Compared to the initial state 21 in which the packing is not sunk, in the state 22 at the time of packing aging, the position where the packing contacts is shifted downward. Even in that case, however, the upper lid continues to descend, and when the upper lid comes into contact with the packing, the drive shaft torque is reliably increased, and the upper lid is securely tightened until the closing torque set value is reached, and the vacuum vessel is sealed. Therefore, there is no problem in exhausting the vacuum vessel. At this time, the closing position of the upper lid is also shifted downward.

  The position of the top dead center and the bottom dead center of the upper lid may be set by setting a pulse counter as usual, or by another method such as a limit switch.

  FIG. 4 is a graph showing the relationship between the position of the vacuum vessel top lid and the drive shaft torque when a contact accident occurs in the vacuum drying apparatus according to the present invention. For example, when the transport mechanism or the like comes into contact with the descending upper lid due to insufficient retraction, the drive shaft torque rapidly increases. At this time, if an emergency stop torque value smaller than the closing torque set value is set in advance, the torque detection mechanism can detect this and stop the drive of the servo motor. This is effective in reducing damage to the device due to a contact accident, and functions as a safety device.

  However, in this case, in order to prevent the motor from stopping at this small torque value in the normal upper lid closing operation, the emergency stop torque value is detected from the upper lid provided between the front of the upper lid closing position and the bottom dead center. When the upper lid exists inside the closed section 23, it is necessary to make it invalid. The upper lid closing section start position may be set by setting a pulse counter or a limit switch. Even if the emergency stop torque is not set, the motor is stopped at least when the closing torque value is detected in the event of a contact accident, so that there is a moderate damage reduction effect.

  When evacuation of the vacuum container is started, the upper lid is pushed with a large force by the atmospheric pressure, so that it usually tends to descend further than the upper lid closing position. Therefore, in order to prevent the upper lid opening / closing mechanism from being destroyed at this time, a play capable of absorbing this movement is required between the upper lid and the upper lid opening / closing mechanism.

As described above, in the vacuum drying apparatus according to the present invention, the opening and closing of the upper lid is directly driven by the servo motor, and the torque detection mechanism is provided in the drive system, so that the opening and closing of the upper lid is quick and the upper lid closing position is located. Since it is controlled not by the coordinates but by the tightening torque value, the upper lid is securely closed even if the packing is sunk, which not only solves the problem that it takes a long time to evacuate due to leakage. Even if the upper lid interferes with another device, damage can be minimized.

DESCRIPTION OF SYMBOLS 1 ... Decompression drying apparatus 2 ... Vacuum container main body 3 ... Vacuum container upper cover 4 ... Upper cover opening-closing mechanism 5 ... Servo motor 6 ... Exhaust pipe 7 ... Packing 8 ... Vacuum Total 9 ... Transport mechanism 10 ... Substrate holding mechanism 20 ... Upper lid moving direction 21 ... Initial state 22 ... State during packing aging 23 ... Upper lid closed section 30 ... Glass substrate 31 ... R pixel 32 ... G pixel 33 ... B pixel 34 ... Black matrix

Claims (3)

  A vacuum drying apparatus used for removing a solvent in a coating film applied on a substrate, comprising: a vacuum container comprising a main body and an upper lid; and an upper lid opening / closing mechanism for opening and closing the vacuum container by moving the upper lid up and down. An exhaust device that exhausts air in the vacuum container; a transport mechanism that transports the substrate into the vacuum container; and a substrate holding mechanism that holds the substrate in the vacuum container. It is driven by a motor and has a drive torque detection mechanism in the drive system, and the servo motor stops when the drive torque detection mechanism detects a preset closing torque value and closes the upper lid. A vacuum drying apparatus characterized by that.   The reduced-pressure drying apparatus according to claim 1, wherein the drive torque detection mechanism is built in the servo motor.   The drive torque detection mechanism can set an emergency stop torque value smaller than this in addition to the closing torque value, the upper lid starts to descend from the top dead center, and the bottom dead center from the front of the upper lid closing position. The servo motor stops when the drive torque detection mechanism detects the emergency stop torque value in the interval until the upper lid closing interval provided between them, and in the upper lid closure interval, the drive torque detection mechanism 3. The vacuum drying apparatus according to claim 1, wherein the servo motor is stopped when the closing torque value is detected.

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