JP2005326529A - Vacuum processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum processing apparatus wherein a prescribed degree of vacuum can be always obtained even when exhaustion and damage of an O-ring are generated. <P>SOLUTION: A liquid crystal injection apparatus 100 as the vacuum processing apparatus is an apparatus for performing a process to inject a liquid crystal into a liquid crystal cell 6 from a liquid crystal pan 4 in which the liquid crystal is stored. A variable valve 8 adjusting the speed for evacuating the inner part of a chamber 20 is provided in an exhausting system and a vacuum gauge 11, a vacuum meter 12, a controller 13 and an actuator 14 are provided in the apparatus. The controller 13 checks the degree of vacuum measured by the vacuum meter 12 and actuates the variable valve 8 via the actuator 14 so that the exhausting speed is a predetermined exhausting speed to adjust the exhausting speed in an initial step for evacuating the inner part of the chamber 20 from atmospheric pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum processing apparatus represented by, for example, a liquid crystal injection apparatus that injects liquid crystal into a liquid crystal cell.

  In a vacuum processing apparatus, a chamber for processing an object to be processed in a vacuum atmosphere is provided with a door for taking in and out the object to be processed, and an O-ring is provided between the chamber body and the door. It is configured so that it can be sealed. When vacuum processing is performed, after the workpiece is set in the chamber under atmospheric pressure, the chamber is evacuated from atmospheric pressure to a predetermined vacuum level. In this early stage of exhaust, it is necessary to exhaust slowly over time in order to prevent the workpiece in the chamber from being damaged by a sudden pressure change, and it is automatically performed according to a preset exhaust velocity program. Exhaust has been done.

  In the vacuum processing apparatus, the door is opened and closed for loading and unloading the processing object for each batch, so that the O-ring is consumed and damaged when used for a long time. If the O-ring is worn or damaged, the chamber and the door may not be intimately contacted at the initial stage of exhaust, and the original exhaust speed program may not provide a predetermined degree of vacuum, which hinders the manufacturing process. It will be.

(1) A vacuum processing apparatus according to a first aspect of the present invention includes a vacuum chamber that performs predetermined vacuum processing on an object to be processed, an exhaust system that includes an exhaust speed adjusting means for adjusting an exhaust speed of the vacuum chamber, and a vacuum chamber A pressure measuring means for measuring the pressure in the vacuum chamber, and when the pressure measured by the pressure measuring means becomes a reference pressure lower than atmospheric pressure, the exhaust speed adjusting means is operated according to a predetermined exhaust program to Control means for exhausting the pressure to a final pressure suitable for vacuum processing and for gradually increasing the exhaust capacity of the exhaust speed adjusting means until the pressure in the vacuum chamber reaches the reference pressure.
(2) The vacuum processing apparatus according to claim 2 is an apparatus for performing processing for injecting liquid crystal into a liquid crystal cell from a liquid crystal container for storing liquid crystal as the predetermined vacuum processing in the vacuum processing apparatus according to claim 1, And a moving mechanism for relatively moving the liquid crystal cell and a gas introduction system for introducing an inert gas into the vacuum chamber.
(3) In the vacuum processing apparatus according to claim 1 or 2, the exhaust speed adjusting means is preferably a rotary variable valve provided in a piping part of the exhaust system and increasing or decreasing an exhaust port cross-sectional area of the piping part.

  According to the present invention, the evacuation speed adjusting means is provided to control the evacuation speed in the vacuum chamber at the initial stage of evacuation. Therefore, even if the O-ring is worn or damaged, a predetermined vacuum required for vacuum processing is obtained. You can get a degree.

  Hereinafter, as a vacuum processing apparatus according to an embodiment of the present invention, a liquid crystal injection apparatus will be described as an example with reference to FIGS. FIG. 1 is an overall configuration diagram schematically showing an outline of a liquid crystal injection device according to the present embodiment.

  The liquid crystal injection device 100 includes a chamber body 1, an opening / closing door 2, an elevating mechanism 3 for placing the liquid crystal dish 4 and elevating in the arrow direction, and a holder 5 for holding the liquid crystal cell 6. An O-ring 1a is interposed between the chamber main body 1 and the open / close door 2 so that a sealed state can be maintained. The door 2 is provided with a lock mechanism (not shown), and the door 2 can be pressed against the chamber body 1. The chamber 20 is a housing composed of a chamber body 1, an O-ring 1 a and an opening / closing door 2.

  An exhaust pump 7, a variable valve 8, a main valve 9, and a leak valve 10 are connected to the chamber body 1 through piping. The variable valve 8 and the main valve 9 are arranged in parallel to the exhaust pump 7. The variable valve 8 is a rotary variable valve that increases or decreases the cross-sectional area of the exhaust port of the piping portion, that is, the opening degree, according to the rotation angle of the valve body. The rotary variable valve can adjust the exhaust speed more accurately than the baffle type exhaust speed adjusting mechanism. The leak valve 10 is connected by piping to a gas supply tank (not shown).

  In addition, the liquid crystal injection device 100 includes a vacuum gauge 11, a vacuum gauge 12, a controller 13, and an actuator 14. The vacuum gauge 12 measures the degree of vacuum (pressure value) in the chamber 20 from the pressure information detected by the vacuum gauge 11. The controller 13 switches between the variable valve 8 and the main valve 9 in accordance with a preset exhaust program (exhaust process recipe), or via the actuator 14 based on the degree of vacuum measured by the vacuum gauge 12. The exhaust speed is controlled by changing the opening of the variable valve 8.

  Hereinafter, the exhaust process associated with the liquid crystal injection process will be described in detail with reference to FIGS. FIG. 2 is a flowchart showing all steps when liquid crystal injection processing is performed using the liquid crystal injection device 100 according to the present embodiment, and processing is performed by a program executed by the CPU of the controller 13. Hereinafter, the opening is defined as 0% when the variable valve 8 is completely closed and 100% when the variable valve 8 is fully opened, and is divided equally between 0% and 100%.

  Prior to starting the program according to FIG. 2, the operator sets the liquid crystal dish 4 and the liquid crystal cell 6 storing the liquid crystal at predetermined positions in the chamber body 1 and closes the open / close door 2. At this stage, the liquid crystal cell 6 is not in contact with the liquid crystal in the liquid crystal dish 4, and the pressure in the chamber 20 is atmospheric pressure. When the program shown in FIG. 2 is started by turning on a start switch (not shown), the liquid crystal injection process is started. In step S1, the opening degree of the variable valve 8 is set to an initial value OP1, for example, 20%. In step S <b> 2, the exhaust in the chamber 20 is performed by the exhaust pump 7 through the variable valve 8.

  In step S3, the pressure in the chamber 20 is checked based on the measurement signal from the vacuum gauge 12. If the pressure in the chamber 20 is equal to or lower than the reference pressure for starting the exhaust program under atmospheric pressure, the process proceeds to step S5, and the opening degree of the variable valve 8 is set according to the exhaust process recipe. % Is maintained. If the pressure in the chamber 20 does not reach the reference pressure, the process proceeds to step S4, and the pressure in the chamber 20 is again increased while gradually increasing the opening of the variable valve 8, that is, increasing α. To check. Since the opening degree of the variable valve 8 is gradually increased, the pressure in the chamber 20 does not change rapidly. If the pressure in the chamber 20 becomes equal to or lower than the reference pressure, the process proceeds to step S5, the opening of the variable valve 8 is reset to 20% of the initial value OP1 according to the exhaust process recipe, and the exhaust program is started.

  In step S6, exhaust for a predetermined time is performed. In step S7, it is checked whether there is a problem in the exhaust state. Here, if there is a problem that disturbs the process, the liquid crystal injection process is interrupted. If there is no problem in the exhaust state, the process proceeds to step S8, the opening degree of the variable valve 8 is set to 0%, and the inside of the chamber 20 is kept in a state of not exhausting for a predetermined waiting time. In step S9, it is checked whether or not the target pressure (target vacuum level) has been reached. If the target pressure has not been reached, the process returns to step S5, the opening of the variable valve 8 is reset to the first opening OP2, for example, 30% according to the exhaust process recipe, and steps S5 to S9 are repeated. If the target pressure has been reached in step S9, the process proceeds to step S10. Here, the target pressure in step S9 is set as P1 and P2 (<P1) with respect to the initial value OP1 and the first opening degree OP2, respectively. That is, the target pressure is set for each opening degree of the variable valve 8.

  In step S10, the exhaust path is switched from the variable valve 8 to the main valve 9, and exhaust is continued in step S11. In step S12, it is checked whether or not the final target pressure, that is, the degree of vacuum at which liquid contact is possible, for example, 1 Pa, has been reached. The liquid contact is to immerse the end face (liquid crystal inlet) of the liquid crystal cell 6 in the liquid crystal in the liquid crystal dish 4. If the final target pressure has not been reached in step S12, the process returns to step S11 and further exhausts. If the final target pressure has been reached in step S12, the main valve 9 is closed in step S13, and the chamber 20 is held in a state where the chamber 20 is not exhausted for a predetermined waiting time.

  After the standby time in step S13 has elapsed, the process proceeds to step S14. In step S <b> 14, the liquid crystal dish 4 is raised by the elevating mechanism 3 to perform liquid contact. In step S <b> 15, the inlet of the leak valve 10 is opened and an inert gas such as nitrogen gas is introduced into the chamber 20. In step S16, it is checked whether or not the pressure in the chamber 20 has reached a predetermined pressure (1 atm or slightly higher than 1 atm). If the predetermined pressure has been reached, the process waits as it is, and if the predetermined pressure has not been reached, the process returns to step S15 to continue the introduction of nitrogen gas. During the standby time of step S17, the inside of the liquid crystal cell 6 is vacuum and the outside is 1 atm or slightly higher than 1 atm, so that the liquid crystal in the liquid crystal dish 4 is in the liquid crystal cell 6 due to the atmospheric pressure difference. Injected into. When the predetermined time has elapsed, the injection operation is normally completed.

  Hereinafter, the time change of the state of the valves 8 and 9 and the time change of the degree of vacuum in the chamber 20 will be specifically described along the processing steps of the flowchart of FIG. 2 with reference to FIG. The upper part of FIG. 3 shows the time change of the state of the variable valve 8 and the main valve 9, and the lower part of FIG. 3 shows the time change of the degree of vacuum in the chamber 20. The time when the exhaust is started is set to t0, and at this time, the opening degree of the variable valve 8 is set to 20% of the initial value. However, the process described in the present embodiment assumes that the O-ring 1a is not in an ideal state but is slightly worn or damaged.

  The pressure in the chamber 20 is checked at time t1. If the pressure in the chamber 20 remains atmospheric, the pressure in the chamber 20 is checked again while gradually increasing the opening of the variable valve 8 (step S4). As shown in the figure, since the pressure in the chamber 20 becomes equal to or lower than the reference pressure less than the atmospheric pressure at time t2 (Yes at Step S3), the opening degree of the variable valve 8 is set to 20% (Step S5).

  After exhausting at time t2 to t3 when the opening degree of the variable valve 8 is 20%, the opening degree of the variable valve 8 is set to 0%, and the target pressure (target vacuum degree) is set during the standby time from time t3 to t4. Is checked (step S9). If the target pressure has not been reached, the opening of the variable valve 8 is reset to 30%, and after exhausting from time t4 to t5, the target pressure (target vacuum level) during the standby time from time t5 to t6. It is rechecked whether or not it has been reached (step S9). If the target pressure has been reached (Yes at step S9), the exhaust path is switched from the variable valve 8 to the main valve 9 at time t6 (step S10). Therefore, the use time zone of the variable valve 8 is time t0 to t6, and the variable valve 8 is not used from time t6.

  Exhaust is performed using the main valve 9, and since the final target pressure is reached at time t7, the main valve 9 is closed. This state is a degree of vacuum that can be in contact with the liquid, for example, 1 Pa. After waiting for a predetermined time from time t7, the liquid is contacted (step S14).

  For example, nitrogen gas is introduced into the chamber 20 at time t8 (step S15). In a state where the pressure in the chamber 20 has reached a predetermined pressure (1 atmosphere or slightly higher than 1 atmosphere) (Yes in step S16), the liquid crystal in the liquid crystal dish 4 is injected into the liquid crystal cell 6. Holding for a predetermined time (step S17), the injection operation is normally completed.

  Next, with reference to FIG. 4, the effect of the liquid crystal injection apparatus 100 by this Embodiment is demonstrated. Also in the graph of FIG. 4, times t0, t1, t2, and t3 correspond to the graph of FIG. 3, but the waiting time at times t3 to t4 is 0 and is omitted from the graph. In the above-described process, it is assumed that the O-ring 1a is slightly worn or damaged, and the time change of the pressure in the chamber 20 in this case is represented by a solid line of the curve A. That is, if the O-ring 1a is slightly damaged or the like, the O-ring 1a is not elastically deformed and cannot be covered in a state where the exhaust is gently exhausted. Therefore, by gradually increasing the opening of the variable valve 8, the O-ring 1a is elastically deformed at time T, and thereafter the pressure in the chamber 20 decreases.

On the other hand, in the ideal case where the O-ring 1a is new and not damaged at all, the pressure in the chamber 20 decreases from the exhaust start time (time t0) as shown by the broken line in the curve B.
In this ideal case, from time t0 to t3, the opening degree of the variable valve 8 is constant 20% as shown by the broken line.

  In the present embodiment, a pressure change curve substantially similar to that in an ideal case can be obtained by increasing the opening degree of the variable valve 8 from 20% to 45% during the period from time t1 to t2. Therefore, even if the O-ring 1a is slightly damaged, it can be used normally and the life of the O-ring 1a can be extended. In addition, since the degree of damage to the O-ring 1a can be grasped from the relationship between the opening of the variable valve 8 and the pressure change curve, the maintenance and replacement timing of the O-ring 1a can be predicted, and adverse effects on the production schedule can be avoided. .

As can be seen from the liquid crystal injection apparatus 100 according to the present embodiment described above, the present invention has a step of controlling the pressure (degree of vacuum) in the vacuum chamber until the final pressure is reached according to the exhaust program, and this step is started. It is characterized in that the exhaust capacity is gradually increased when exhausting at least the inside of the vacuum chamber in the atmospheric pressure state in the previous stage. Therefore, the present invention is not limited to the above-described embodiment as long as the characteristics are not impaired. In particular, the present invention can be effectively applied to a vacuum processing apparatus that processes a workpiece to be damaged or a lightweight workpiece such as powder or flakes that are easily damaged by a sudden pressure change in the initial stage of exhaust.
In the present embodiment, the variable valve 8 corresponds to the exhaust speed adjusting means, the vacuum gauge 11 and the vacuum gauge 12 constitute pressure measuring means, and the controller 13 and the actuator 14 constitute control means.

1 is an overall configuration diagram schematically showing an outline of a liquid crystal injection device according to an embodiment of the present invention. It is a flowchart which shows all the processes which perform a liquid-crystal injection process using the liquid-crystal injection apparatus which concerns on embodiment of this invention. FIG. 3 is a graph corresponding to the flowchart of FIG. 2, which is a graph (upper stage) showing a time change of the state of the variable valve 8 and the main valve 9 and a graph (lower stage) showing a time change of the degree of vacuum. FIG. 3 is a graph (upper stage) showing the time change of the opening degree of the variable valve 8 in the initial stage of FIG. 2 and a graph (lower stage) showing the time change of the degree of vacuum.

Explanation of symbols

1: Chamber body 1a: O-ring 2: Opening / closing door 3: Elevating mechanism 4: Liquid crystal dish 5: Holder 6: Liquid crystal cell 7: Exhaust pump 8: Variable valve 9: Main valve 10: Leak valve 11: Vacuum gauge 12: Vacuum gauge 13: Controller 14: Actuator 20: Chamber 100: Liquid crystal injection device

Claims (3)

A vacuum chamber for performing predetermined vacuum processing on an object to be processed;
An exhaust system having an exhaust speed adjusting means for adjusting an exhaust speed of the vacuum chamber;
Pressure measuring means for measuring the pressure in the vacuum chamber;
When the pressure measured by the pressure measuring means becomes a reference pressure lower than atmospheric pressure, the exhaust speed adjusting means is operated according to a predetermined exhaust program, and the pressure in the vacuum chamber is suitable for the vacuum processing. A vacuum processing apparatus comprising: a control means for evacuating to a final pressure and gradually increasing the exhaust capacity of the exhaust speed adjusting means until the pressure in the vacuum chamber reaches the reference pressure. The vacuum processing apparatus according to claim 1,
The predetermined vacuum process is a process of injecting the liquid crystal into a liquid crystal cell from a liquid crystal container that stores liquid crystal,
A vacuum processing apparatus, further comprising: a moving mechanism that relatively brings the liquid crystal container and the liquid crystal cell closer together and a gas introduction system that introduces an inert gas into the vacuum chamber. The vacuum processing apparatus according to claim 1 or 2,
The vacuum processing apparatus, wherein the exhaust speed adjusting means is a rotary variable valve that is provided in a piping section of the exhaust system and increases or decreases an exhaust port cross-sectional area of the piping section.

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