KR100202741B1 - High-frequency induction coil for vacuum evaporator - Google Patents

Abstract

The present invention relates to a high frequency induction coil of a high frequency induction vacuum evaporation machine.

Conventional vacuum evaporators use a resistive heat source of the electrothermal heater 54 to heat-evaporate deposits. Therefore, a large contact resistance is generated in the bonding terminals, and a large amount of high temperature is generated. Since the resistance is increased due to the change in characteristics and the service life is short, the heat transfer heater 54 is changed after about 400 to 1000 times of deposition, and the operation of the fastening means 74 is troublesome in replacing the heat transfer heater 54 There is a problem that the product generated during the deposition is separated at the time of fastening the electrothermal heater 54 and the deposition chamber 52 is contaminated, resulting in defective deposition.

The present invention is characterized in that a metal plate (4) having excellent electrical conductivity and heat resistance is rounded in a donut shape a suitable number of times to form an induction chamber (6) capable of placing a crucible in the center, (12) and (14) having fixing grooves (8) and (10) are formed in the metal plate (4), and the metal plate (4) A plurality of cutting grooves 18 are formed at equal intervals in the peripheral portion of the coil 2 so as to face the center of the coil 2 so that the high frequency power is concentrated and distributed in the center induction chamber 6, So as to be vacuum-deposited.

Description

High frequency induction coil for vacuum deposition

FIG. 1 is a perspective view of the present invention. FIG.

FIG. 2 is a perspective view of another embodiment of the present invention. FIG.

FIG. 3 is a sectional view of the use state of the present invention. FIG.

FIG. 4 is a diagram showing the melting curve of a deposition material according to frequency in high-frequency induction heating; FIG.

FIG. 5 is a perspective view of the electrothermal heater portion used in the conventional vacuum evaporator; FIG.

FIG. 6 is a sectional view of a conventional vacuum evaporator in use; FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

2: induction coil 4: metal plate

6: guide chamber 8, 10: fixing groove

12, 14: power supply terminal 16:

18: incision groove 20: evaporation dish

22: Deposition

The present invention relates to a high frequency induction coil of a high frequency induction vacuum evaporation machine.

Vacuum evaporator is suitably used for deposition of surface coating (plating) of various cathode ray tube (CRT) panel, mirror, semiconductor, automobile parts and various optical parts such as reflector, metallization of synthetic resin products, There are various problems in the evaporators because they are the energization heating method in which the deposition material is heated and deposited using the resistive heat source of the electrothermal heater.

6, the conventional vacuum evaporator is provided with the electrothermal heater 54 in the evaporation chamber (vacuum chamber) 52 in which the evaporation opening 50 is formed and the evaporation chamber 52 at the lower end thereof, A heating chamber 56 and a vacuum pump 58 are provided and a sealing packing 60 is provided around the opening 50. A melting channel 62 formed at the upper center of the electrothermal heater 54 (Usually aluminum) 64 is placed on the opening 50 in consideration of the degree of vapor deposition, and the evaporation material 66 is placed on the opening 50. In a state where the vacuum of the evaporation chamber 52 is maintained by the vacuum pump 58 When the high-current AC power source (AC 60 Hz: 68) is supplied to the electrothermal heater 54, the electrothermal heater 54 becomes 1500 And the deposition material 64 is melted and sublimated (evaporated) by the thermal energy, and is deposited on the material to be deposited 66. [0064]

The heat transfer heater 54 as the heat generating means is provided with the bonding terminals 72 on the upper part of the pair of support rods 70 as shown in FIG. 5 and the opposite ends of the heat transfer heaters 54 to the opposite bonding terminals 72 A large amount of high temperature is generated at the contact portion because the power source 68 applied is a low potential high current and the contact portion is lifted due to thermal stress and oxidation, Since the resistance is increased due to the change in characteristics and the service life is short, the heat transfer heater 54 is replaced after about 400 to 1000 times of deposition. When the heat transfer heater 54 is exchanged, The work is troublesome because the work is accompanied by the tightening work and the product generated when the deposition is performed is separated at the time of fastening the electrothermal heater 54 and the evaporation chamber 52 is contaminated.

Further, when the electrothermal heater 54 is used, the heat accumulation rate (heat shrinkability of the electrothermal heater) is high, but the temperature rising time is slow and the cooling time is slow due to non- The temperature of the contact portion rises by the contact resistance when the high temperature of the contact heater is increased to increase the resistance of the contact portion and to increase the deposition efficiency and to increase the initial temperature of the electrothermal heater 54. [ And precipitation wear is further intensified, so that the life is shortened.

Accordingly, the present inventor filed the same application as the present application for a high-frequency induction heating vacuum deposition method which can perform economical and high-quality vacuum deposition by using high frequency induction heating, which has a number of merits in place of energization heating by an electric heater It is an object of the present invention to provide a high frequency induction coil for a vacuum evaporator which is a heating means for practically achieving a vacuum deposition method using high frequency induction heating.

In order to achieve the above-mentioned object, a high frequency induction coil is wound around a central portion of an evaporation dish on which evaporation material is placed, and a coil is formed into a plate shape to increase the heat radiation efficiency during cooling, The induction coils are connected to a plurality of induction coils by means of a single number or a connection line depending on the conditions of deposition materials and deposition conditions.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a high frequency induction coil 2 according to the present invention. A metal plate 4 having excellent electrical conduction and heat resistance is wound round a predetermined number of times in a donut shape to form an induction chamber 6 are formed and the power feeding terminals 12 and 14 having the fixing grooves 8 and 10 at the upper and lower ends of the coil 2 are formed.

The cross-sectional area of the coil 2 is set to a cross-sectional area having a sufficient heat capacity. Since the coil 2 has a larger surface area than the thicker one, it can be manufactured as a pipe or a plate. When the pipe 2 is used as a pipe, the volume is relatively large and occupies a large amount of occupied space. So that efficient cooling is achieved.

The high temperature is generated only in the evaporation dish 20 placed in the induction chamber 6 by the electromagnetic induction and only the low heat is generated due to the high temperature radiation generated in the evaporation dish 20, The contact resistance between the support rod 36 and the feed terminal 12 (14) does not matter, and when the vacuum is released after deposition, the coil 2 is naturally cooled without cooling, Is achieved more easily.

In the above, the coil (2) It is possible to use aluminum or aluminum alloy or platinum plating on the surface of copper which is easy to manufacture and obtain even if the melting point is somewhat low and the coil 2 can be manufactured by copper only, In the case of vapor deposition, it is not preferable because there may be a defective cyanide (a phenomenon in which a blue color is stronger than other colors in a cathode ray tube) due to the chemical action of copper.

On the other hand, a magnetic force line penetrating into the evaporation dish as a load generates a current. On the contrary, a magnetic force line flowing to the outside does not contribute to efficiency and is a heat loss. Therefore, in the present invention, And a plurality of cut-away grooves 18 are formed at equal intervals of three or more to allow the high-frequency power to be concentratedly distributed at the center.

FIG. 2 is a perspective view of another embodiment of the present invention. The high frequency induction coils of FIG. 1 are spaced apart from each other by a predetermined distance and then connected by a connection line 16, And a plurality of suitable induction coils 2 may be connected in series or in parallel using not only two but also connecting wires.

When the plurality of coils 2 are connected using the connection line 16, the coils 2 are aligned in the same direction so as to exclude interference between them.

In order to transmit maximum energy to the load, the coil 2 should be designed so that the evaporation dish 20 as a load is coupled as close as possible to the induction chamber 6 and crosses at a portion where many magnetic lines of force are heated. The higher the density, the more current is induced in the load.

Further, when the evaporation dish 20 is not located in the center of the induction chamber 6 but slightly shifted toward one side of the coil 2, the heating speed is increased by crossing more magnetic lines of force on the surface adjacent to the coil 2, It is preferable to install the evaporation dish 20 so as to be located at the center of the induction chamber 6 because the coupling degree is lowered and is heated at a slow speed.

On the other hand, the heating coil used for high-frequency heating is not constant in shape and size, and can be composed of various colors. The shapes of the coils are determined according to the heating area, the frequency, the material and the application of the heating material, and the penetration depth of the heating material. As the types of the coils are varied, the shapes of the heating coils can also be widely varied, such as circular, square, pancake, spiral, And the inductance loss is large when the number of coils is small because the frequency of use is high. As a result, the overlapping portion between the connecting lead length and the coils appears, so the heating efficiency of the single winding coil is lower than that of the circular multiple coil.

The heating efficiency refers to the degree to which the electric field generated in the coil is applied to the load. Since the circular coil among the various types of coils has the highest heating efficiency, in the present invention, the circular coil 2 .

If the interval of the coil 2 is narrow, the heating depth is deepened. On the contrary, if the pitch of the coil is wide, the heating depth is low and the heating depth of the coil center is slightly deeper than the outer angle.

Coils with dense pitches have deeper depths because the magnetic flux penetration is deeper than the surface, but if the coil spacing is too narrow, mutual resistance to current flow will occur and eventually the inductance balance will collapse . On the contrary, in the case of a coil having a wide pitch, the magnetic flux is diverged to a large area, so that a part of the magnetic flux is lost and the heating depth is thinned.

Therefore, when the coil 2 is manufactured, the gap between the turns of the coil 2 is approximately 0.5 to 1.5 times the thickness of the coil to obtain uniform heating. When the length of the coil 2 is 8 times or less the diameter, Heating and higher efficiency can be obtained.

In order to match a coil with a small inductance to a higher frequency, there is a simple method of widening the coil width. However, since there is a limitation, the coil can be considered as a series, parallel, The calculation of the total coil value can be easily obtained by Ohm's law.

In addition, when the plurality of coils 2 are connected in series or in parallel using the connection wires 16, the directions of the coils should coincide with each other so as to exclude mutual interference. If the magnitudes of the loads applied to the coils are different By adjusting the coil value, the heating temperature can be adjusted. In this case, the coil value can be adjusted by using a tuning stub or a trumborn.

However, since the heating efficiency varies depending on the frequency, it is very important to select the frequency in a high frequency application. If the penetration depth is too high, the outer surface of the evaporation dish 20 is heated, and the efficiency of the heat is increased. On the other hand, if the penetration depth is too high due to the high frequency, So that the magnetic fluxes cancel each other out, which also lowers the efficiency.

Therefore, the selection of an appropriate frequency should be selected in consideration of the aspect of heat exiting from the surface of the molten metal to the outside and the factor of the magnetic line canceling on the central portion. In the present invention, the frequency suitable for melting is lower than quench- ing at an effective high frequency of 50 kHz to 1000 kHz, A frequency in the range of 100 kHz to 300 kHz is suitable, in which the penetration depth is 10% to 20% of the diameter of the evaporation dish 20.

On the other hand, in the present invention, the evaporation dish (20) It is preferable to fabricate a material having a melting point much higher than that of the material such as tungsten or molybdenum because the high temperature before and after the heat treatment is generated. Further, if the thickness of the evaporation dish 20 is made thinner than the penetration depth, effect can achieve rapid heating since the high frequency power is also concentratedly heated over the entire portion of the evaporation dish 20, and rapid cooling can be achieved at the same time, so that the deposition rate can be improved.

FIG. 4 shows a melt line according to the frequency, wherein the melt line refers to a line where the deposit 22 melts and becomes a boundary between the melt and the material. In the case of a low frequency, the temperature of the deposition material is higher than ambient, the melting wire is in a V shape, the molten wire is in a molten state in an appropriate state, the molten wire is in a U shape, And the molten wire becomes W-shaped.

In high-frequency induction heating, eddy currents are mainly responsible for heating, which generates heat when a current flows through a resistive conductor, which is proportional to the square of the current flowing and the time the resistors and currents flow through the conductor. The eddy current (We) generated in the heating furnace high frequency induction coil is as follows.

ef ² Bm ² --------- (expression)

here e is the frequency, f is the frequency, and Bm is the magnetic flux density. As shown in the above equation, the eddy current loss is proportional to the square of the frequency, so that the frequency is more influenced by the hysteresis loss.

That is, when the frequency is low, the hysteresis is large and the frequency is high, the eddy current loss increases. When the frequency is higher than 50 kHz, the loss is relatively small because the eddy current loss, which is proportional to the square of the frequency, Hysteresis is negligible when the operating frequency is significantly higher than 100 kHz. Of course, non-magnetic and magnetic materials such as copper and aluminum, even if the frequency of use is somewhat low, will heat up above the magnetic transformation point to lose hysteresis loss and then be heated only by eddy currents.

Reference numeral 24 denotes an evaporation chamber, reference numeral 26 denotes a vacuum valve, reference numeral 28 denotes a vacuum pump, reference numeral 30 denotes a deposition opening, reference numeral 32 denotes a deposit, reference numeral 34 denotes a hermetic packing, Reference numeral 38 denotes a fixing means, 42 denotes an evaporation plate support rod, 44 denotes a heat reflecting plate, 46 denotes a deposition material, 48 denotes a deposited material detection sensor, and FV denotes a high frequency power source.

According to the present invention constructed as described above, the feed terminals 12 and 14 of the induction coil 2 are placed on and contacted with a pair of the power supply supporting rods 36 provided in the evaporation chamber 24, And the evaporation plate 20 is placed on the support rod 42 and the evaporation material 46 is placed on the evaporation material plate 40 in a size taking the deposition area into consideration. The evaporation material 32 is placed on the opening 30, (Several tens KVAR) having a frequency in the range of 100 kHz to 300 kHz is supplied to the power supply terminals 12 and 14 of the coil 2 through the power supply support rods 36 while the vacuum of the evaporation chamber 24 is maintained. The high frequency supplied to the coil 2 is guided to the evaporation dish 20 so that the evaporation dish 20 is heated to 1500 And the deposition material 46 is instantaneously melted and evaporated (or sublimated) by the thermal energy, and is deposited on the deposited material 32.

Since a plurality of cutting grooves 18 are formed at the edge of the induction coil 2 so that the high frequency current is guided to the center of the coil 2 to be concentratedly distributed and thus mostly guided to the nearby evaporation dish 20, .

The coil 2 and the evaporation chamber 24 are cooled by releasing the vacuum after the deposition. In the conventional case, forced cooling is performed due to the axial heat resistance of the electrothermal heater 54. However, in the present invention, The natural quench of the coil 2 is achieved by shutting off the high-frequency power supply FV applied to the coil 2 and releasing the vacuum without requiring forced cooling since it is produced in a wide rectangular shape and generates only a slight heat.

In the present invention, the feed terminals 12 and 14 are fastened to the power supply support rods 36 so that a slight contact resistance is generated. However, high temperature is generated in the evaporation dish 20 as a load due to the induction action, There is no wear of the contact portion of the coil 2 and the lifetime of the coil 2 is permanently increased. Therefore, the replacement of the fastening structure can be easily performed even if the replacement is not troublesome.

Since the evaporation dish 20 and the evaporation material 46 themselves, which are to be heated, are directly heated by using the high frequency induction heating, the efficiency is high, the evaporation material is instantly melted to finely fuse the evaporation particles, It is possible to reduce the amount of the deposition material and the operation is free because it does not require preliminary time such as preheating or slow cooling.

In addition, it is a useful invention having an effect that the evaporation dish 20 and the evaporation material 46 to be heated can be completely separated and blocked from the coil 2 as the heating source, thereby preventing various contamination.

Claims (3)

An induction chamber 6 capable of appropriately winding the plate-shaped metal plate 4 having excellent electrical conduction and heat resistance in a donut shape and accommodating the evaporation plate of the evaporation material in the center thereof is formed and the high frequency power supply terminal 12) (14). The high frequency induction coil according to claim 1, wherein a plurality of cut-out grooves (18) are formed at equal intervals in the edge portion of the metal plate (4). The high frequency induction coil according to claim 1 or 2, wherein the plurality of coils (2) are connected by a connection line (16).