Vacuum drying apparatus and vacuum drying method using the same

An embodiment of the present invention provides a vacuum drying apparatus and a vacuum drying method. The vacuum drying apparatus includes a chamber in which a substrate table is arranged, the chamber being provided with a wind deflector therein, wherein the wind deflector comprises a top opening, a bottom opening and a body part connecting the top opening with the bottom opening. During the vacuum drying, the bottom opening is in tight contact with a surface of the substrate table, and there is a gap between the top opening and the top of the chamber and a material on the substrate table is covered by the wind deflector.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Chinese Patent Application No. 201510079423.1 filed on Feb. 13, 2015 in the State Intellectual Property Office of China, the whole disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure relates to the field of drying technology, in particular, relates to a vacuum drying apparatus and a vacuum drying method using the same.

Description of the Related Art

An OLED display device includes a plurality of film layers arranged in sequence on a substrate. These film layers may be formed by various means such as evaporation, ink jet printing. The ink jet has advantages of such as high utilization ratio of material, large size of printing. Thus, it is an important means for producing large size OLED display apparatus in batch.

Typically, after the ink jet printing operation has been completed, it is desired to move the substrate into a vacuum drying apparatus to be dried such that the solvent in the ink droplets is volatilized to form a film layer finally. The conventional vacuum drying apparatus is shown inFIG. 1. The vacuum drying apparatus includes a chamber1′ in which a substrate table2′ is arranged and at the bottom of which two extraction ports3′ are arranged symmetrically. The substrate4′ (called as material) is arranged on the substrate table2′. During drying, the extraction ports3′ extract gases from the chamber1′ to reduce the pressure in the chamber1′, so as to promote the volatilizing the solvent in the ink droplets for drying.

During the drying, gas flow in the chamber1′ is directed to the extraction ports3′ from the substrate table2′. The closer the gas flow to the extraction ports3′, the larger the speed of the gas flow becomes. It causes the speed of the gas flow at the peripheral region of the substrate4′ to be greater than that of the gas flow at the central region of the substrate4′, such that the speed of drying ink droplets at the peripheral region of the substrate4′ to be greater than that of drying ink droplets at the central region of the substrate4′. After the ink droplets at the peripheral region of the substrate4′ have been dried, the ink droplets at the central region of the substrate4′ are still in liquid state, and thus they will flow towards the peripheral region of the substrate4′, and finally, the film layer at the peripheral region of the substrate4′ has a thickness greater than that of the film layer at the central region of the substrate4′. It may degrade the display effects of the OLED display apparatus.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a vacuum drying apparatus and a vacuum drying method that can improve the phenomenon that the drying speed at various positions on the material is not uniform during the vacuum drying.

In view of the above, embodiments of the present invention are provided by way of examples as follows.

An embodiment of the present invention provides a vacuum drying apparatus includes a chamber in which a substrate table is arranged, the chamber being provided with a wind deflector therein, wherein the wind deflector comprises a top opening, a bottom opening and a body part connecting the top opening with the bottom opening, and wherein during the vacuum drying operation, the bottom opening is in tight contact with a surface of the substrate table, and there is a gap between the top opening and the top of the chamber and a material on the substrate table is covered by the wind deflector.

In an example, the body part of the wind deflector is a side wall connecting the top opening with the bottom opening.

In an example, the wind deflector is movable up and down.

In an example, the vacuum drying apparatus further comprises a wind deflector elevation driver connected with the wind deflector and configured to drive the wind deflector to move up and down.

In an example, the wind deflector elevation driver comprises an elevation mechanism configured to drive the wind deflector to move up and down and an elevation driving mechanism configured to drive the elevation mechanism to move up and down.

In an example, the elevation driving mechanism comprises a motor, a coupling, a lead screw, a nut and a guide shaft, and wherein the motor is connected to an end of the lead screw by the coupling, the nut being mounted around the lead screw and connected with the elevation mechanism, and wherein the elevation mechanism moves up and down in a direction of the guide shaft, the guide shaft being connected to the top of the chamber and perpendicular to the substrate table.

In an example, the elevation mechanism comprises an elevation plate and an elevation shaft, the elevation plate being connected with the nut and connected with the wind deflector by the elevation shaft passing though the top of the chamber, and wherein the elevation plate is provided with a guide hole thereon matched with the guide shaft, the elevation plate being placed idly around the guide shaft through the guide hole.

In an example, the elevation plate is connected with a guide sleeve in the guide hole, the guide sleeve being placed idly around the guide shaft.

In an example, the elevation driving mechanism comprises a cylinder and a guide shaft, the cylinder comprising a cylinder rod which has an end connected with the elevation mechanism, and wherein the elevation mechanism is movable up and down in a direction of the guide shaft, the guide shaft being connected to the top of the chamber and perpendicular to the substrate table.

In an example, the elevation mechanism comprises an elevation plate and an elevation shaft, the elevation plate being connected with the cylinder rod and connected with the wind deflector by the elevation shaft passing through the top of the chamber, and wherein the elevation plate is provided with a guide hole thereon matched with the guide shaft, the elevation plate being placed idly around the guide shaft through the guide hole.

In an example, the elevation plate is connected with a guide sleeve in the guide hole, the guide sleeve being placed idly around the guide shaft.

In an example, the elevation mechanism further comprises a retractable bellows mounted around the elevation shaft and configured to seal a region connecting the elevation plate with the top of the chamber.

In an example, the wind deflector elevation driver further comprises an elevation limit mechanism configured to limit an upper limit position and a lower limit position of the wind deflector.

In an example, the elevation limit mechanism comprises an upper limit position sensor, a lower limit position sensor and a sensor mount, the upper limit position sensor and the lower limit position sensor being fixed to the sensor mount, all of the upper limit position sensor, the lower limit position sensor and the motor being connected with a controller, and wherein the controller is configured to control the work state of the motor on the basis of the signals transmitted from the upper limit position sensor and/or the lower limit position sensor.

In an example, the side wall of the wind deflector is at an angle less than or equal to 90 degrees with respect to the surface of the substrate table.

In an example, the wind deflector has a square or circular cross section parallel to the bottom opening.

In an example, the material is substrate of an OLED display device which has been processed by an ink jet printing, and a layer of ink droplets is formed on the substrate by the ink jet printing.

In an example, an extraction port is arranged at the bottom of the chamber or a plurality of extraction ports are distributed uniformly or in a predetermined form on the positions corresponding to the wind deflector at the bottom of the chamber.

The embodiment of the present invention provides a vacuum drying apparatus as described above. During drying operation, the bottom opening of the wide deflector is in tight contact with the substrate table while leaving a gap between the top opening and the top of the chamber such that the gas flow in the wind deflector is directed from a surface of the substrate table through the top opening of the wind deflector to the external of the wind deflector and then out of the chamber. In this way, the gas flow is prevented from flowing directly out of the chamber from the substrate table. As the speed of the gas flow at various positions in the wind deflector is relatively uniform, the phenomenon that the drying speed is not uniform at various positions of the material may be suppressed.

An embodiment of the present invention also provides a vacuum drying method for drying material using the vacuum drying apparatus as described above, the method comprising:

providing the material onto the substrate table;

covering the material by the wind deflector, the bottom opening of the wind deflector being in tight contact with the substrate table, and leaving a gap between the top opening of the wind deflector and the top of the chamber; and

evacuating the chamber.

The embodiment of the present invention provides a vacuum drying method for drying material using the vacuum drying apparatus as described above, to cover the material by the wind deflector. During drying operation, the bottom opening of the wide deflector is in tight contact with the substrate table while leaving a gap between the top opening of the wind deflector and the top of the chamber such that the gas flow in the wind deflector is directed from a surface of the substrate table through the top opening of the wind deflector to the external of the wind deflector and then out of the chamber. In this way, the gas flow is prevented from flowing directly out of the chamber from the substrate table. As the speed of the gas flow at various positions in the wind deflector is relatively uniform, the phenomenon that the drying speed is not uniform at various positions of the material may be suppressed.

EXPLANATION OF REFERENCE NUMERALS

Exemplary embodiments of the present disclosure will be described clearly and entirely with reference to the attached drawings. The embodiments are only given by way of examples, instead of all of embodiments of the present invention. From these embodiments, all of other embodiments that can be envisaged apparently by the skilled person in the art will fall within the scope of the present disclosure.

An embodiment of the present invention provides a vacuum drying apparatus. As illustrated inFIG. 2, the vacuum drying apparatus includes a chamber1. A substrate table2and a wind deflector3are arranged in the chamber1. The wind deflector3includes a top opening32, a bottom opening33and a body part31(for example, the side wall shown) connecting the top opening32with the bottom opening33. During the vacuum dry, the bottom opening33is in tight contact with a surface of the substrate table2, and there is a gap between the top opening32and the top of the chamber1and the material4is arranged in the wind deflector3or covered by the wind deflector3.

FIG. 2shows two extraction ports (not marked) arranged symmetrically at the bottom of the chamber1. It should be understood that the skilled person in the art may envisage one extraction port is arranged at center of the bottom of the chamber1or a plurality of extraction ports are distributed uniformly or in a predetermined form on the positions, corresponding to the wind deflector, at the bottom of the chamber1so as to achieve more uniform distribution of gas flow, thoughFIG. 2only shows two extraction ports. In an example, the plurality of extraction ports in form of a ring may be arranged at the bottom of the chamber1. In the art, an arrangement of extraction ports in a certain predetermined form of distribution may be obtained by such as simulations or experiments to achieve optimum distribution of gas flow.

In particular, in an example, the material4is a substrate of an OLED display device which has been processed by the ink jet printing. As an example, a layer of ink droplets is formed on the substrate by the ink jet printing. By means of the vacuum drying apparatus according to the present disclosure, the solvent in the ink droplets on the substrate may be volatized to finally form various film layers for the OLED display device.

The embodiment of the present invention provides a vacuum drying apparatus as described above. During drying operation, the bottom opening of the wind deflector is in tight contact with the substrate table while leaving a gap between the top opening and the top of the chamber such that the gas flow in the wind deflector is directed from a surface of the substrate table through the top opening of the wind deflector to the external of the wind deflector and then out of the chamber. In this way, the gas flow is prevented from flowing directly out of the chamber from the substrate table. As the speed of the gas flow at various positions in the wind deflector is relatively uniform, the phenomenon that the drying speed is not uniform at various positions of the material may be suppressed.

In order to place the material4in the wind deflector3, preferably, the wind deflector3may be movable up and down. The wind deflector3may be elevated manually. In order to improve the elevation speed and accuracy of the wind deflector3, preferably, the wind deflector3may be elevated automatically.

When the wind deflector3is elevated automatically, the vacuum drying apparatus includes a wind deflector elevation driver50connected with the wind deflector3and configured to drive the wind deflector3to move up and down.

In an example, the wind deflector elevation driver50includes an elevation mechanism52configured to drive the wind deflector3to move up and down and an elevation driving mechanism51configured to drive the elevation mechanism52to move up and down. Specifically, the elevation driving mechanism51is disposed above the elevation mechanism52.

In order that the skilled person in the art can understand the wind deflector elevation driver50in the embodiment of the present invention more clearly, the embodiment of the present invention provides the following two structures of the wind deflector elevation driver50. The two structures of the wind deflector elevation driver50have different driving modes from each other.

In a first wind deflector elevation driver50, the elevation driving mechanism51includes a motor511, a coupling514, a lead screw515, a nut516and a guide shaft523. The motor511is connected to an end of the lead screw515by the coupling514, the nut516being mounted around the lead screw515and connected with the elevation mechanism52. The elevation mechanism52moves up and down in a direction of the guide shaft523. One end of the guide shaft523is connected to the top of the chamber1and perpendicular to the substrate table2while the other end of the guide shaft523is connected with a fixing plate513. The guide shaft523supports the fixing plate513in which a through hole is arranged so as to allow the lead screw515to pass through. In addition, the motor511is fixed on the fixing plate513by a motor mount512. In operation, the motor511drives the lead screw515to rotate by the coupling514such that the nut516drives the elevation mechanism52to move up and down.

As shown, the elevation mechanism52includes an elevation plate521and an elevation shaft522. The elevation plate521is connected with the nut516and connected with the wind deflector3by the elevation shaft522passing though the top of the chamber1. When the lead screw515rotates, the nut516drives the elevation plate521to move up and down to further drive the wind deflector3to move up and down.

In a further embodiment, the elevation plate521moves up and down in a direction of the guide shaft523. In particular, the connecting means between the elevation plate521and the guide shaft523may be arranged such that the elevation plate521is provided with a guide hole (not marked) thereon matched with the guide shaft523, the elevation plate521being placed idly around the guide shaft523through the guide hole. In order to improve the wear resistance of the elevation plate, preferably, the elevation plate521is connected with a guide sleeve in the guide hole, the guide sleeve being placed idly around the guide shaft523. The guide sleeve may be made from wear-resistant metals such as copper. Such connection means results in a simple structure of the wind deflector elevation driver50. As the elevation plate521is placed idly around the guide shaft523, the guide shaft523may limit the rotation of the elevation plate521along with the lead screw while limiting the elevation direction of the elevation plate521.

Certainly, the elevation plate521and the guide shaft523may also be connected by other means, for example, the elevation plate is provided with a T-shaped protrusion thereon while the guide shaft is provided with a guide groove thereon corresponding to the protrusion. Certainly, the guide shaft may be provided with the T-shaped protrusion thereon while the elevation plate may be provided with the guide groove thereon corresponding to the protrusion. The T-shaped protrusion and the guide groove cooperate with each other and slide with respect to each other such that the elevation plate moves up and down in the direction of the guide shaft. They may also limit the rotation of the elevation plate along with the lead screw.

In a second wind deflector elevation driver50, the elevation driving mechanism includes a cylinder and a guide shaft. The cylinder includes a cylinder rod which has an end connected with the elevation mechanism. The elevation mechanism is movable up and down in a direction of the guide shaft. One end of the guide shaft is connected to the top of the chamber and perpendicular to the substrate table while the other end of the guide shaft is connected to the fixing plate. The guide shaft supports the fixing plate in which a through hole is arranged to allow the cylinder rod to pass through. In addition, the cylinder is fixed on the fixing plate by a cylinder mount. When the cylinder works, the cylinder rod drives the elevation mechanism to move up and down.

In this case, the elevation mechanism includes an elevation plate and an elevation shaft, the elevation plate being connected with the cylinder rod and connected with the wind deflector by the elevation shaft passing through the top of the chamber. When the cylinder rod moves up and down, it drives the elevation plate to move up and down.

In addition, the connecting means between the elevation plate and the guide shaft is same to that in the first wind deflector elevation driver50. For example, the elevation plate is provided with a guide hole thereon matched with the guide shaft, the elevation plate being placed idly around the guide shaft through the guide hole.

It should be noted that the skill person in the art can also acquire other available means apparently on the basis of the above two wind deflector elevation driver50. The detailed description will be omitted herein.

In a further embodiment, in consideration of the elevation shaft522passing through the top of the chamber1, in order to prevent the elevation shaft522from reducing the vacuum degree in the chamber1during the movement or elevation, preferably, the elevation mechanism52may further include a retractable bellows524mounted around the elevation shaft522and configured to hermetically connect the elevation plate521with the top of the chamber1. When the elevation shaft522moves up and down, the retractable bellows524extends or retracts along with it and seals a region connecting the elevation plate521with the top of the chamber1so as to avoid reduction of the vacuum degree in the chamber1.

In addition, the wind deflector elevation driver50further includes an elevation limit mechanism53configured to limit an upper limit position and a lower limit position of the wind deflector3. As illustrated inFIG. 3, when the wind deflector3is raised to the upper limit position, the wind deflector3departs from the substrate table2. At that time, the material4may be placed on the substrate table2. As illustrated inFIG. 2, when the wind deflector3is lowered to the lower limit position, the bottom opening33of the wind deflector3comes into tight contact with the substrate table2. At that time, the chamber1may be evacuated to dry the material4.

In an example, the elevation limit mechanism53includes an upper limit position sensor531, a lower limit position sensor532and a sensor mount533, the upper limit position sensor531and the lower limit position sensor532being fixed to the sensor mount533. As illustrated inFIG. 3, the sensor mount533is fixed between the fixing plate513and the top of the chamber1. The upper limit position sensor531corresponds to the highest position of the elevation plate521to limit the upper limit position of the wind deflector3. As illustrated inFIG. 2, the lower limit position sensor532corresponds to the lowest position of the elevation plate521to limit the lower limit position of the wind deflector3.

All of the upper limit position sensor531, the lower limit position sensor532and the motor511are connected with a controller. The controller is configured to control the work state of the motor511on the basis of the signals transmitted from the upper limit position sensor531and/or the lower limit position sensor532. When the wind deflector3reaches the upper limit position, the upper limit position sensor531transmits a signal to the controller and the controller controls the motor511to stop working. When the wind deflector3reaches the lower limit position, the lower limit position sensor532transmits a signal to the controller and the controller controls the motor511to stop working.

In order to achieve uniform speed of gas flow in the wind deflector3, the side wall31of the wind deflector3is at an angle less than or equal to 90 degrees with respect to the surface of the substrate table2. When the side wall31of the wind deflector3is at an angle equal to 90 degrees with respect to the surface of the substrate table2, the wind deflector3has a shape of cylinder and has a simple production process. When the side wall31of the wind deflector3is at an angle less than 90 degrees with respect to the surface of the substrate table2, the size of the top opening32is less than that of the bottom opening33, which may enable the speed of the gas flow in the wind deflector3to become more uniform.

Preferably, as illustrated inFIGS. 4-5, the wind deflector3has a square or circular cross section parallel to the bottom opening33. In this case, the process for producing the wind deflector3becomes relatively simple. Certainly, the shape of the wind deflector3may also be other shape such that the wind deflector3is adapted to the shape of the material4or the speed of the gas flow in the wind deflector3becomes more uniform.

An embodiment of the present invention also provides a vacuum drying method for drying the material4using the vacuum drying apparatus as described above, as illustrated inFIGS. 2 and 3. The vacuum drying method includes: providing the material4onto the substrate table2; covering the material4by the wind deflector3, the bottom opening33of the wind deflector3being in tight contact with the substrate table2, and leaving a gap between the top opening32of the wind deflector3and the top of the chamber1; and evacuating the chamber1.

It should be noted that before the material4is placed on the substrate table2, the wind deflector3may be raised at first, and the wind deflector3will not be lowered until the material4has been placed on the substrate table2such that the bottom opening33of the wind deflector3comes into tight contact with the substrate table2and the wind deflector3covers the material4.

The embodiment of the present invention provides a vacuum drying method for drying the material using the vacuum drying apparatus as described above, to cover the material by the wind deflector. During drying operation, the bottom opening of the wide deflector is in tight contact with the substrate table while leaving a gap between the top opening and the top of the chamber such that the gas flow in the wind deflector is directed from a surface of the substrate table through the top opening of the wind deflector to the external of the wind deflector and then out of the chamber. In this way, the gas flow is prevented from flowing directly out of the chamber from the substrate table. As the speed of the gas flow at various positions in the wind deflector is relatively uniform, the phenomenon that the drying speed is not uniform at various positions of the material may be suppressed.

Although several exemplary embodiments have been shown and described, the present invention is not limited to those and it would be appreciated by those skilled in the art that various changes, equivalents or modifications may be made to these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.