Large area evaporation boat

Abstract

The present invention relates to the technical field of flexible luminescent material evaporation, and in particular to a large-area evaporation boat, comprising an evaporating dish, a heating portion and a temperature-equalizing portion; a material inlet is formed on the top of the evaporating dish, and a cavity for evaporating material is formed inside; the heating portion is installed at the bottom of the evaporating dish for heating the evaporating dish; the temperature-equalizing portion is installed between the top surface of the heating portion and the bottom surface of the evaporating dish. By adding the temperature-equalizing portion between the heating portion and the evaporating dish, each part of the bottom of the evaporating dish can be heated evenly, ensuring that the vapor density of each area above the evaporating dish is the same, which is beneficial to improving the coating quality.

Description

Technical Field

[0001] The invention relates to the technical field of flexible luminescent material evaporation, in particular to a large-area evaporation boat. Background Art

[0002] In the manufacturing process of OLED (Organic Light-Emitting Diode), thousands of processes are involved. The substrate coating process of OLED is one of the thousands of processes. In the substrate coating process of OLED, the evaporation material placed on the evaporation boat is heated and evaporated with the help of an evaporation boat, so that the evaporation material is heated to produce evaporation material and is plated on the flexible substrate. As the size of OLED continues to increase, it is necessary to evaporate the evaporation material on a larger area of ​​flexible substrate. Due to the small size of the traditional evaporation boat, it is no longer suitable for the production of large-size OLEDs. After the size of the traditional evaporation boat is increased proportionally, the various parts of the evaporation dish are prone to uneven heating, which seriously affects the coating quality. Therefore, how to make the various parts of the larger evaporation dish evenly heated has become a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0003] The invention provides a large-area evaporation boat, which is used to solve the problem of how to make each part of a relatively large-sized evaporation dish be heated evenly.

[0004] In one aspect, the present invention provides a large-area evaporation boat, comprising:

[0005] The evaporating dish has a material inlet formed on the top and an evaporating material containing cavity formed inside;

[0006] A heating part, installed at the bottom of the evaporating dish, used for heating the evaporating dish;

[0007] The temperature-uniform part is installed between the top surface of the heating part and the bottom surface of the evaporating dish so that all parts of the bottom of the evaporating dish are heated evenly.

[0008] In some embodiments, the temperature-averaging portion is a temperature-averaging plate with a solid structure.

[0009] In some of the embodiments, a first thermally conductive silicone grease layer is disposed between the top surface of the temperature homogenizing plate and the bottom surface of the evaporating dish.

[0010] In some of the embodiments, a heating chamber is formed at the bottom of the temperature-averaging portion, a heat transfer chamber is formed at the top, a gas diffusion channel connected to the heating chamber and the heat transfer chamber respectively is formed in the middle, and a liquid reflux channel connected to the heating chamber and the heat transfer chamber respectively is formed at the edge; a liquid storage pad is provided in the heating chamber; a liquid medium capable of phase change is stored in the liquid storage pad.

[0011] In some embodiments, the gas diffusion channel is a Laval channel.

[0012] In some embodiments, the heating unit includes:

[0013] Electric heating element;

[0014] The insulating heat-conducting shell is wrapped around the electric heating element, and the top surface is in contact with the bottom surface of the temperature-averaging part.

[0015] In some of the embodiments, a second thermally conductive silicone grease layer is disposed between the top surface of the insulating thermally conductive shell and the bottom surface of the temperature-uniform portion.

[0016] In some embodiments, it also includes:

[0017] The temperature measuring probe is embedded in the temperature-averaging part or in the bottom of the evaporating dish.

[0018] In some embodiments, a heat-insulating cavity is formed inside the side wall of the evaporation dish.

[0019] In some embodiments, the bottom surface of the evaporating dish is greater than 300 cm 2 , the distance between the top surface and the bottom surface is less than 10cm.

[0020] The beneficial effects of the present invention are as follows: the large-area evaporation boat of the present invention can add evaporation material into the evaporation material holding chamber through the feed port by providing an evaporation dish, a heating part and a temperature-equalizing part. The heating part is installed at the bottom of the evaporation dish, and is used to heat the evaporation dish, so that the evaporation material is heated to produce an evaporation substance and is plated on a large-sized flexible substrate. The temperature-equalizing part is installed between the top surface of the heating part and the bottom surface of the evaporation dish, so that each part of the bottom end of the evaporation dish is evenly heated, ensuring that the steam density of each area above the evaporation dish is the same, which is beneficial to improve the coating quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of some specific embodiments of a large-area evaporation boat of the present invention;

[0022] Figure 2 It is a schematic structural diagram of some other specific embodiments of a large-area evaporation boat of the present invention;

[0023] Figure 3 yes Figure 1 The schematic diagrams of the structures of some specific embodiments of the heating part in the large-area evaporation boat are shown.

[0024] In the accompanying drawings, 110, evaporating dish; 111, heat-insulating cavity; 120, heating part; 121, electric heating element; 122, insulating heat-conducting shell; 130, temperature-averaging part; 131, heating cavity; 132, heat transfer cavity; 133, gas diffusion channel; 134, liquid reflux channel; 135, liquid storage pad; 140, first thermal grease layer; 150, second thermal grease layer; 160, temperature measuring probe; 200, evaporating material. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] As described in the background technology, as the size of OLEDs continues to increase, it is necessary to evaporate evaporation materials on a larger area of ​​flexible substrates. Since the size of traditional evaporation boats is small, they are no longer suitable for the production of large-sized OLEDs. After the size of traditional evaporation boats is increased proportionally, various parts of the evaporation dish are prone to uneven heating, which seriously affects the coating quality. Therefore, how to make various parts of a larger-sized evaporation dish evenly heated has become a technical problem that needs to be solved urgently by those skilled in the art.

[0027] To solve the above problems, refer to Figure 1 , Figure 2 and Figure 3 The present invention provides a large-area evaporation boat, comprising an evaporation dish 110, a heating unit 120 and a temperature-uniform unit 130. It should be noted that the bottom surface area of ​​the evaporation dish 110 is greater than 300 cm 2 , and can even reach several square meters, and the distance between the top surface and the bottom surface is less than 10cm. That is, the area of ​​the evaporating dish is large, and the depth of the evaporating material holding cavity is shallow, which can meet the coating needs of large-sized flexible substrates. A feed inlet is formed at the top of the evaporating dish 110, and an evaporating material holding cavity is formed inside the evaporating dish 110. The evaporating material 200 can be added to the evaporating material holding cavity through the feed inlet. The heating part 120 is installed at the bottom of the evaporating dish 110, and is used to heat the evaporating dish 110 so that the evaporating material 200 is heated to produce evaporation material and is plated on a large-sized flexible substrate. The temperature-averaging part 130 is installed between the top surface of the heating part 120 and the bottom surface of the evaporating dish 110. By adding the temperature-averaging part 130 between the heating part 120 and the evaporating dish 110, each part of the bottom of the evaporating dish 110 can be evenly heated, ensuring that the steam density of each area above the evaporating dish is the same, which is beneficial to improve the coating quality.

[0028] In some embodiments, such as Figure 1As shown, the temperature balancing part 130 is a solid temperature balancing plate made of heat-conducting materials such as stainless steel, copper or aluminum, which can evenly disperse heat to various parts of the bottom of the evaporating dish 110. Preferably, the temperature balancing plate is made of copper, which has higher heat conduction efficiency. The area of ​​the temperature balancing plate should be equal to or slightly larger than the bottom area of ​​the evaporating dish 110.

[0029] In other embodiments, such as Figure 2 As shown, a heat receiving chamber 131 is formed at the bottom of the temperature-averaging portion 130. A heat transfer chamber 132 is formed at the top of the temperature-averaging portion 130. A gas diffusion channel 133 is formed in the middle of the temperature-averaging portion 130. The gas diffusion channel 133 is connected to the heat receiving chamber 131 and the heat transfer chamber 132 respectively. A liquid reflux channel 134 is formed at the edge of the temperature-averaging portion 130. The liquid reflux channel 134 is connected to the heat receiving chamber 131 and the heat transfer chamber 132 respectively. A liquid storage pad 135 is installed in the heat receiving chamber 131. The liquid storage pad 135 stores a liquid medium that can undergo phase change. Figure 2 The direction of the middle arrow shows the flow direction of the gaseous medium and the liquid medium. When the heating part 120 heats the heat receiving chamber 131, the liquid medium is converted into a high-pressure gaseous medium, flows into the heat transfer chamber 132 through the gas diffusion channel 133, and diffuses rapidly in the heat transfer chamber 132. Afterwards, when the gaseous medium encounters the side wall of the temperature equalizing part 130 with a lower temperature, it is converted into a liquid medium, and flows back into the heat receiving chamber 131 through the liquid reflux channel 134, and diffuses rapidly in the heat receiving chamber 131 with the help of the liquid storage pad 135. Compared with the solid structure of the temperature equalizing plate, the temperature equalization effect is better.

[0030] It should be noted that the microstructure of the liquid storage pad 135 is composed of a series of interconnected micro channels.

[0031] Preferably, the gas diffusion channel 133 is a Laval channel, which can accelerate the gaseous medium to improve the heat conduction efficiency.

[0032] Preferably, there are more than two gas diffusion channels 133 , which are evenly distributed along the circumference of the temperature-averaging portion 130 to improve heat conduction efficiency.

[0033] It should be noted that when the temperature averaging portion 130 is a solid temperature averaging plate, there is always a gap between the top surface of the temperature averaging plate and the bottom surface of the evaporating dish 110, and the gap cannot be observed from a macroscopic point of view. However, the gap will affect the heat conduction efficiency. Therefore, a first thermal grease layer 140 is provided between the top surface of the temperature averaging plate and the bottom surface of the evaporating dish 110, which effectively improves the heat conduction efficiency.

[0034] Specifically, in the example, Figure 1 and Figure 3As shown, the heating part 120 includes an electric heating element 121 and an insulating heat-conducting shell 122. The electric heating element 121 can be connected to an external power source and can convert electrical energy into heat energy to heat the temperature-averaging part 130 and the evaporating dish 110. The insulating heat-conducting shell 122 is coated on the outside of the electric heating element 121, and the top surface is in contact with the bottom surface of the temperature-averaging part 130, playing the role of insulation and heat conduction.

[0035] Preferably, the material of the heating element is any one of tungsten, molybdenum, rhenium, and nickel-chromium alloy. The material of the insulating heat-conducting shell 122 is any one of aluminum nitride, boron nitride, silicon carbide, and silicon nitride.

[0036] Preferably, the heating portion 120 is circular, square, triangular or irregular in shape.

[0037] Preferably, a second thermally conductive silicone grease layer 150 is disposed between the top surface of the insulating heat-conducting shell 122 and the bottom surface of the temperature-averaging portion 130. The second thermally conductive silicone grease layer 150 can fill the microscopic gap between the top surface of the insulating heat-conducting shell 122 and the bottom surface of the temperature-averaging portion 130 to improve heat conduction efficiency.

[0038] It should be noted that if Figure 2 As shown, when a heating cavity 131 is formed at the bottom of the temperature-averaging portion 130, a heat transfer cavity 132 is formed at the top, a gas diffusion channel 133 is formed in the middle, and a liquid reflux channel 134 is formed at the edge, a heating portion 120 with a smaller size is only required to be arranged directly below the gas diffusion channel 133. In this way, the heating function can be realized by means of a conventional heater with a smaller size without increasing the size of the heating portion 120, which can greatly reduce the difficulty of manufacturing and position transfer of the heating portion 120.

[0039] Specifically, in the exemplary embodiment, the large-area evaporation boat further includes a temperature measuring probe 160 for detecting the temperature of the temperature-averaging portion 130 or the evaporation dish 110 .

[0040] In some embodiments, such as Figure 1 As shown, the temperature measuring probe 160 is embedded in the temperature-averaging portion 130 to detect the temperature of the temperature-averaging portion 130 and thereby control the heating temperature.

[0041] In other embodiments, such as Figure 2As shown, there are two temperature probes 160. One of the temperature probes 160 is embedded in the middle of the bottom of the evaporating dish 110 to detect the temperature of the middle of the bottom of the evaporating dish 110. The other temperature probe 160 is embedded in one side of the bottom of the evaporating dish 110 to detect the temperature of one side of the bottom of the evaporating dish 110. On the one hand, directly embedding the temperature probe 160 in the bottom of the evaporating dish 110 is more conducive to accurately controlling the appropriate heating temperature. On the other hand, the temperatures detected by the two temperature probes 160 can be compared. When the difference in the detected temperature values ​​is greater than 2°C, it proves that a large area of ​​the evaporation boat is abnormal.

[0042] Preferably, the temperature measuring probe 160 is a thermocouple or a platinum resistance.

[0043] Preferably, a heat-insulating cavity 111 is formed inside the side wall of the evaporating dish 110. The heat-insulating cavity 111 has a heat-insulating effect, which can effectively reduce the loss of heat, save electric energy, and extend the heat preservation time of the evaporating dish 110.

[0044] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0045] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0048] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A large-area evaporation boat, characterized in that: include: The evaporating dish has a material inlet formed on the top and a cavity for evaporating material formed inside; the bottom area of ​​the evaporating dish is greater than 300 cm 2 , the distance between the top surface and the bottom surface is less than 10 cm; a heat-insulating cavity is formed inside the side wall of the evaporating dish; A heating unit, installed at the bottom of the evaporating dish, for heating the evaporating dish; A temperature-uniform portion installed between the top surface of the heating portion and the bottom surface of the evaporating dish, so that each part of the bottom end of the evaporating dish is heated uniformly; There are two temperature measuring probes; one of the temperature measuring probes is embedded in the middle of the bottom of the evaporating dish, and is used to detect the temperature of the middle of the bottom of the evaporating dish; the other temperature measuring probe is embedded in one side of the bottom of the evaporating dish, and is used to detect the temperature of one side of the bottom of the evaporating dish; The temperatures detected by the two temperature measuring probes can be compared. When the difference between the detected temperature values ​​is greater than 2°C, it is proved that the large-area evaporation boat is abnormal. A heat receiving cavity is formed at the bottom of the temperature-averaging portion, a heat transfer cavity is formed at the top, a gas diffusion channel is formed in the middle portion and is connected to the heat receiving cavity and the heat transfer cavity respectively, and a liquid reflux channel is formed at the edge and is connected to the heat receiving cavity and the heat transfer cavity respectively; a liquid storage pad is arranged in the heat receiving cavity; a liquid medium capable of phase change is stored in the liquid storage pad; when the heating portion heats the heat receiving cavity, the liquid medium is converted into a high-pressure gaseous medium, flows into the heat transfer cavity through the gas diffusion channel, and diffuses rapidly in the heat transfer cavity; thereafter, when the gaseous medium encounters the side wall of the temperature-averaging portion with a lower temperature, it is converted into a liquid medium, and flows back into the heat receiving cavity through the liquid reflux channel, and diffuses rapidly in the heat receiving cavity with the help of the liquid storage pad; The gas diffusion channel is a Laval channel, which can accelerate the gaseous medium; The heating part is arranged directly below the gas diffusion channel; The heating unit comprises: Electric heating element; An insulating heat-conducting shell, covering the electric heating element, with a top surface in contact with a bottom surface of the temperature-uniform portion; A second thermally conductive silicone grease layer is arranged between the top surface of the insulating thermally conductive shell and the bottom surface of the temperature-uniform portion.

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