VACUUM DEPOSITION HEATING DEVICE

The present invention provides a vacuum deposition heating device, which includes a heating device outer wall (3), a crucible (1) disposed inside the heating device outer wall (3), and a crucible cover (2) positioned on the crucible (1). A primary heating coil (11) is arranged between the crucible (1) and the heating device outer wall (3) and corresponds to outer circumferences of the crucible (1) and the crucible cover (2). The crucible cover (2) has a center in which a jet opening (20) that extends through top and bottom surfaces of the crucible cover (2) is formed. The crucible cover (2) is provided thereon with a secondary heating coil (21) corresponding to an outer circumference of the jet opening (20). The primary heating coil (11) and the secondary heating coil (21) are electrically connected to a power supply and can be controlled individually and independently for heating, so as to effectively reduce a temperature difference in the crucible in a horizontal radial direction to prevent opening jamming and allow for expansion of diameter to thereby increase the amount of material applied, reduce the times of chamber opening, increase manufacturing efficiency. In addition, the structure is simple and the manufacture thereof is easy.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of display technology, and in particular to a vacuum deposition heating device.

2. The Related Arts

Organic light-emitting diode (OLED) is regarded as the next generation of display technology and possesses excellent display performance, particularly being self-luminous, simple structure, ultrathin and ultra-light, fast response speed, wide view angle, low power consumption, and being capable of flexible displaying. Mass production techniques of OLED generally involve vacuum deposition for formation of films of OLED materials.

In a vacuum deposition process conducted in a vacuum deposition chamber, a material is placed in a crucible and the crucible is placed in a heating device to be heated to an evaporation temperature so as to vaporize the material such that the vaporized material molecule jets out of a jet opening of a crucible cover to get deposited on a substrate for formation of a solid state film. Improper control of temperature would cause a relatively low temperature in the crucible cover and vaporized material molecules would deposit on the crucible cover and gets expanded to eventually block (jam) the jet opening of the crucible. Partial jamming of the jet opening will cause inaccuracy of film thickness and thus affecting film quality and the performance of a final product. Full jamming of the jet opening would cause no formation of film and overheating of the material left in the crucible. For the OLED organic materials, overheating would make decomposition of the material, making it useless. Further, preventing opening jamming is the essential requirement for a vacuum deposition process and is also an essential condition for providing high quality films.

To prevent opening jamming and ensure stable vacuum deposition conditions, temperature distribution in two directions, including a vertical axial direction and a horizontal radial direction, of a crucible must be realized. They must meet the following to conditions:

(1) Vertical axial direction: temperature of an upper portion of the crucible must be higher than the temperature of a lower portion, meaning a temperature gradient from top to bottom must be present.

(2) Horizontal radial direction: a temperature difference between a peripheral portion and a central portion of the crucible must be as smaller as possible, meaning the temperature of the crucible must be as consistent as possible in a horizontal direction.

Referring toFIG. 1, a schematic cross-sectional view is given to illustrate a conventional vacuum deposition heating device, which comprises a heating device outer wall300, a crucible100disposed inside the heating device outer wall300, and a crucible cover200positioned on the crucible100. The crucible cover200has a center in which a jet opening201is formed and extending through upper and lower surfaces of the crucible cover200. A heating coil110is arranged between the crucible100and the heating device outer wall300to correspond to outer circumferences of the crucible100and the crucible cover200, wherein the heating coil110has a portion that corresponds to an upper portion of the crucible100and has a relatively large distribution density than a distribution density of a portion of the heating coil110that corresponds to a lower portion of the crucible100so that the upper portion of the crucible is provided with a temperature that is greater than that provided to the lower portion of the crucible. This can effectively overcome the issue that the crucible must show a temperature difference in the vertical direction. However, since the heating coil110is arranged to surround the circumference of the crucible100, there is also a temperature gradient from outer side to inner side in the horizontal direction. In other words, the temperature in the peripheral portion of the crucible100in a radial direction is greater than the temperature in the central portion. The temperature difference in the horizontal radial direction also result in the temperature around the jet opening201of the crucible cover being lower than the temperature around a crucible wall120, and this would impose a great influence on OLED materials having poor thermal conductivity. Further, vaporized material molecules jet out of the jet opening201of the crucible cover is also a process of heat dissipation, and would result in a heat loss rate in the area of opening being greater than that of other portions of the crucible. Heretofore, no technical solution is dedicated to handle the issue of temperature difference in the horizontal radial direction and due to constraints imposed by the temperature difference in the horizontal radial direction, crucibles are prevented from expanding the diameters thereof for the larger the crucible diameter is, the greater the temperature difference would be in the radial direction, making the opening jammed more easily. This condition limits the amount of material that can be received in a crucible and is adverse in reducing the frequency of opening the chamber to change material and maintenance of the machine and thus opposite to the increase of manufacturing efficiency.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a vacuum deposition heating device, which effectively reduces temperature difference in a horizontal radial direction of a crucible, prevents opening from being jammed by material, and allows for expansion of diameter to increase the amount of material applied, reduce the times of opening chamber, and increase the manufacturing efficiency.

To achieve the above object, the present invention provides a vacuum deposition heating device, which comprises heating device outer wall, a crucible disposed inside the heating device outer wall, and a crucible cover positioned on the crucible;

a primary heating coil being arranged between the crucible and the heating device outer wall and corresponding to outer circumferences of the crucible and the crucible cover; the crucible cover having a center in which a jet opening that extends through top and bottom surfaces of the crucible cover is formed, the crucible cover being provided thereon with a secondary heating coil corresponding to an outer circumference of the jet opening; the primary heating coil and the secondary heating coil being electrically connected to a power supply and being independently controllable for heating.

The secondary heating coil is of a helical form, comprising a tailing end located at a terminal of an innermost turn and an electrode end located at a terminal of an outermost turn; the tailing end is positioned on the crucible cover; and the electrode end projects outside the crucible cover and partially extends downward in a vertical direction.

An electrical connector is arranged between the crucible and the heating device outer wall at a location corresponding to a lower tip of the electrode end; the electrode end is inserted into the electrical connector; and the electrical connector is electrically connected to a heating circuit.

The primary heating coil has a coil distribution density arranged in an upper portion of the crucible and greater than a coil distribution density arranged in a lower portion of the crucible.

In a vacuum deposition process, application of electricity to the primary heating coil and the secondary heating coil is controlled individually so as to have a temperature of the crucible cover higher than a temperature of the crucible.

The secondary heating coil is provided with a protective cover.

The protective cover is made of a metal.

The protective cover and the secondary heating coil are welded together; or alternatively, the protective cover is provided with a retention slot and the secondary heating coil is fit into and retained in the retention slot.

The crucible cover is provided with a first thermal couple at a location corresponding to an outer edge of the secondary heating coil to monitor a temperature of the crucible cover; and the crucible is provided with a second thermal couple at a location adjacent to a bottom thereof to monitor a temperature of the crucible.

The present invention also provides a vacuum deposition heating device, which comprises a heating device outer wall, a crucible disposed inside the heating device outer wall, and a crucible cover positioned on the crucible;

a primary heating coil being arranged between the crucible and the heating device outer wall and corresponding to outer circumferences of the crucible and the crucible cover; the crucible cover having a center in which a jet opening that extends through top and bottom surfaces of the crucible cover is formed, the crucible cover being provided thereon with a secondary heating coil corresponding to an outer circumference of the jet opening; the primary heating coil and the secondary heating coil being electrically connected to a power supply and being independently controllable for heating;

wherein the secondary heating coil is of a helical form, comprising a tailing end located at a terminal of an innermost turn and an electrode end located at a terminal of an outermost turn; the tailing end is positioned on the crucible cover; and the electrode end projects outside the crucible cover and partially extends downward in a vertical direction;

wherein the primary heating coil has a coil distribution density arranged in an upper portion of the crucible and greater than a coil distribution density arranged in a lower portion of the crucible;

wherein in a vacuum deposition process, application of electricity to the primary heating coil and the secondary heating coil is controlled individually so as to have a temperature of the crucible cover higher than a temperature of the crucible.

The efficacy of the present invention is that the present invention provides a vacuum deposition heating device, which comprises a primary heating coil arranged around circumferences of a crucible and a crucible cover and a secondary heating coil arranged on the crucible cover, wherein the primary heating coil and the secondary heating coil are controllable independently for heating so as to ensure a temperature from top to bottom present in the crucible and at the same time effectively reducing a temperature difference in the crucible in a horizontal radial direction to prevent opening jamming and allow for expansion of diameter to thereby increase the amount of material applied, reduce the times of chamber opening, increase manufacturing efficiency. In addition, the structure is simple and the manufacture thereof is easy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 2-4, the present invention provides a vacuum deposition heating device, which comprises a heating device outer wall3, a crucible1disposed inside the heating device outer wall3, and a crucible cover2positioned on the crucible1.

Specifically, a primary heating coil11is arranged between the crucible1and the heating device outer wall3and corresponds to outer circumferences of the crucible1and the crucible cover2. The crucible cover2has a center in which a jet opening20that extends through top and bottom surfaces of the crucible cover2is formed to allow, in a vacuum deposition process, vaporized deposition material molecules to jet out of jet opening20and get deposited on a substrate to form a solid state film. The crucible cover2is provided thereon with a secondary heating coil21corresponding to an outer circumference of the jet opening20. The primary heating coil11and the secondary heating coil21are electrically connected to a power supply and can be controlled individually and independently for heating so that control of temperature distribution of the crucible2in both a vertical axial direction and a horizontal radial direction can be achieved simultaneously, whereby a temperature difference in the horizontal radial direction of the crucible can be effectively reduce, while a temperature gradient is maintained from top to bottom of the crucible to effectively prevent opening jamming.

Specifically, the secondary heating coil21is of a helical form, comprising a tailing end211located at a terminal of an innermost turn and an electrode end212located at a terminal of an outermost turn. The tailing end211is positioned on the crucible cover2and the electrode end212projects outside the crucible cover2and partially extends downward in a vertical direction.

Specifically, an electrical connector22is arranged between the crucible1and the heating device outer wall3at a location corresponding to a lower tip of the electrode end212. The electrode end212is partly inserted into the electrical connector22. The electrical connector22is electrically connected to a heating circuit23. The electrical connector22can be in the form of a socket for easy insertion and withdrawal, whereby during a vacuum deposition process, the secondary heating coil21can be conveniently removed for changing the material disposed in the crucible. Once the crucible is re-installed, the secondary heating coil21can be conveniently re-mounted.

Specifically, a heating device base24is arranged under the crucible1.

Specifically, the primary heating coil11has a coil distribution density that is arranged in an upper portion of the crucible1and is greater than a coil distribution density thereof arranged in a lower portion of the crucible1so that the upper portion of the crucible2is provided with a temperature that is slightly higher than that of the lower portion. This effectively handles the issue that the crucible2needs to have a temperature difference in the vertical axial direction and a temperature gradient from top to bottom is present in the crucible2thereby effectively preventing opening jamming and maintaining stable deposition conditions.

Specifically, in a vacuum deposition process, application of electricity to the primary heating coil11and the secondary heating coil21can be controlled individually such that the temperature of the crucible cover2is higher than the temperature of the crucible1thereby effectively reducing a temperature difference of the crucible2in the horizontal radial direction to further prevent opening jamming and better maintain stable deposition conditions.

As shown inFIG. 4, the secondary heating coil21is provided with a protective cover30to provide protection to the secondary heating coil21and prevent deformation thereof. The protective cover30has a shape and a size respectively corresponding to a shape and a size of the secondary heating coil21in order to house and receive the secondary heating coil21therein. Further, the protective cover30has a center in which a hole31is formed and corresponds to the jet opening20. The hole31has a size substantially equal to or greater than a size of the jet opening20.

Specifically, the protective cover30is made of metal, such as titanium, aluminum, and stainless steel.

Specifically, the protective cover30can be fixed, through welding, to the secondary heating coil21; or alternatively, the protective cover30is provided with a retention slot and the secondary heating coil21is fit into and retained in the retention slot.

Specifically, the crucible cover2is provided with a first thermal couple25at a location corresponding to an outer edge of the secondary heating coil21to monitor the temperature of the crucible cover2; and the crucible1is provided with a second thermal couple26at a location adjacent to a bottom thereof to monitor the temperature of the crucible1so as to ensure that the temperature of the crucible cover2is slightly higher than the temperature of the crucible1and also lower than a decomposition temperature of the material.

In summary, the present invention provides a vacuum deposition heating device, which comprises a primary heating coil arranged around circumferences of a crucible and a crucible cover and a secondary heating coil arranged on the crucible cover, wherein the primary heating coil and the secondary heating coil are controllable independently for heating so as to ensure a temperature from top to bottom present in the crucible and at the same time effectively reducing a temperature difference in the crucible in a horizontal radial direction to prevent opening jamming and allow for expansion of diameter to thereby increase the amount of material applied, reduce the times of chamber opening, increase manufacturing efficiency. In addition, the structure is simple and the manufacture thereof is easy.