JP3291216B2 - Liquid thermosetting resin curing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for curing a liquid thermosetting resin used in a molding step of sealing a light emitting element such as an LED lamp with a liquid thermosetting resin. After curing of the resin by heat), it is suitably used for curing an object which should not cause uneven curing such as keloid in the appearance of the cured product, such as a cured product having a glass effect.

[0002]

2. Description of the Related Art Conventional curing apparatuses include a batch type oven (stand-alone) type and a conveyor curing oven type.

As shown in FIG. 6, in a batch oven type, a mold jig 82 is provided at the center of a curing furnace 81, and a heater 83 as a heat source is provided on one side wall of the curing furnace 81. A hot-air stirring type provided with a stirring blade 84 for stirring the air in the curing furnace 81 is generally used.

As a batch oven type, a hot air circulation type shown in FIG. 7 has also been proposed. This hot air circulation type curing apparatus has a mold jig 92 installed in the center of a curing furnace 91 and openings 93 and 94 formed in a top wall and a lower portion of one side wall of the curing furnace 91, respectively.
These openings 93 and 94 are communicated in an airtight manner by a communication pipe 95.

A sensor 96 for detecting the temperature in the curing furnace 91 is mounted in the communication pipe 95 at a position near the opening 93, and a fan 97 is provided at an upper position of the sensor 96. ) Is provided with a heater 98 as a heat source. Further, the baffle plate 9 for stably guiding the warm air (indicated by a white arrow in the drawing) blown out from the opening 94 toward the bottom surface of the mold jig 92 is provided in the curing furnace 91.
9,99 are provided. In the above configuration, the openings 93 and 94, the communication pipe 95, the fan 97, and the heater 98 constitute a hot air circulation unit.

[0006] Conveyor curing furnace types include:
There are a hot air stirring type shown in FIG. 6 with a conveyor and a hot air circulation type shown in FIG. 7 with a conveyor.

[0007]

However, the hardening device of the hot air stirring type shown in FIG. 6 has the following various problems. That is, (1) it is not possible to preferentially supply hot air to a place where it is desired to supply it. (2) Since the heating of the mold jig 82 is heat conduction by hot air (air contact), it takes time until the mold jig 82 reaches the temperature in the curing furnace 81 (a large heating loss). (3) In the curing furnace 81, a temperature difference occurs between a place where the hot air is well stirred and a place where it is not.

[0008] Of these problems, in particular, regarding the problem (1), when a light emitting element such as an LED lamp is sealed with a resin, for example, the following problems occur. That is, LE
For a product in which a light emitting element such as a D lamp is sealed with a resin, what is required for the function is the beauty of the surface condition of the lens surface. It is desirable to accelerate the curing of the resin. However, with the above-described conventional hot-air stirring type curing device, it is not possible to supply hot air preferentially to the bottom surface side of the resin filling portion serving as the lens surface side. Shrinkage occurs, causing a problem that a lens surface having a beautiful shape cannot be formed.

In the curing apparatus of the hot air circulation type shown in FIG. 7, the problems (1) and (3) hardly occur, but the problem (2) similarly occurs.

Further, in the conveyor curing furnace of the type shown in FIG. 6 in which a conveyor is attached to the hot-air stirring type, the above-mentioned (1), (2), (3) )
Problems occur.

In the conveyor curing oven of the type shown in FIG. 7 in which a conveyor is attached to the hot air circulation system, the problems (1) and (3) described above hardly occur.
The problem (2) similarly occurs.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and an object of the present invention is to supply hot air preferentially to a place where hot air is to be supplied, to prevent heating loss of a mold jig, An object of the present invention is to provide a curing device for a liquid thermosetting resin in which a heating time is reduced, a temperature distribution in a furnace is stabilized, and the like.

[0013]

According to a first aspect of the present invention, there is provided an apparatus for curing a liquid thermosetting resin in which a light emitting element attached to a lead frame is inserted into a liquid thermosetting resin. A mold jig filled with a curable resin, a heating plate for directly heating by contacting the lower surface of the mold jig installed in a curing furnace, and heating means for heating the heating plate, By heating the heating plate by a heating means, the mold jig is directly heated to cure the filled thermosetting resin.

According to a second aspect of the present invention, there is provided an apparatus for curing a liquid thermosetting resin according to the first aspect, wherein the hot air is circulated from a lower side to an upper side in the curing furnace. The air circulation means is provided.

According to a third aspect of the present invention, there is provided an apparatus for curing a liquid thermosetting resin according to the first or second aspect, wherein the heat capacity of the heating plate is twice or more the heat capacity of the mold jig. By setting, the temperature drop of the heating plate due to heat exchange is suppressed.

According to a fourth aspect of the present invention, there is provided an apparatus for curing a liquid thermosetting resin, comprising: a mold jig filled with the liquid thermosetting resin in a state where the light emitting element attached to the lead frame is inserted. A heating plate for directly contacting and heating the lower surface of the mold jig installed in the curing furnace, a far-infrared heater for heating the heating plate, and hot air from the lower side to the upper side in the curing furnace. A hot air circulating means for circulating toward the mold, and heating the heating plate with the far-infrared heater to directly heat the mold jig to cure the filled thermosetting resin. .

According to a fifth aspect of the present invention, there is provided a liquid thermosetting resin curing apparatus according to the second, third or fourth aspect, wherein the heating means and the hot air circulating means can be individually controlled. It was done.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the liquid thermosetting resin curing device of the present invention is applied to a batch type oven type.

This curing device has a structure in which a heating plate 3 is installed at the center of a curing furnace 1 and a mold jig 2 is placed on the heating plate 3. The heating plate 3 has a heater 4 and a thermocouple 5 as heat sources embedded therein.

That is, by adopting a structure in which the mold jig 2 is placed on the heating plate 3, the heat efficiency is improved by the heat conduction due to the contact. At this time, the heat capacity of the heating plate 3 is set to be at least twice the heat capacity of the mold jig 2 in consideration of the heat taken from the heating plate 3 in the initial stage of heating the mold jig 2. Thereby, the temperature drop of the heating plate 3 due to heat exchange can be suppressed. As a material of the heating plate 3, a stainless steel material having the highest heat capacity per unit volume is preferable in consideration of thermal efficiency.

On the other hand, openings 11 and 12 are formed in the top wall of the curing furnace 1 and the lower part of one side wall, respectively.
The communication pipes 13 communicate airtightly with each other.

A sensor 14 for detecting the temperature in the curing furnace 1 is mounted in the communication pipe 13 at a position near the opening 11, and a fan 15 is provided at an upper position thereof. 2) is provided with a heater 16 which is a heat source for circulating hot air. The curing furnace 1 has an opening 1
There are provided air guide plates 17, 17 for guiding the warm air (indicated by white arrows in the figure) blown out of the mold 2 to the mold jig 2. The air guide plates 17 and 17 are
By changing the air flow to the mold jig 2, the heating of the mold jig 2 can be eliminated, and the heating can be stably performed. Theoretically, if the air volume sent to each part of the mold jig 2 (central part, left and right side parts, etc.) is the same, warm air sent to each part of the mold jig 2 (central part, left and right parts, etc.) Are the same.

In the above configuration, the openings 11 and 12, the communication pipe 13, the fan 15, and the heater 16 constitute hot air circulation means.

FIG. 2 shows a step of resin-sealing a semiconductor element using a curing device having such a structure.

That is, after filling the resin filling portion 22 of the mold case 21 provided in the mold jig 2 with the liquid thermosetting resin 35, the LED lamp or the like attached to the lead frame cup 32 of the lead frame 31. The light emitting element 33 is inserted to a predetermined position and placed on the heating plate 3 in the curing furnace 1. At this time, the heater 4 in the heating plate 3 has already been turned on, and the temperature of the heating plate 3 is controlled to a preset temperature. At this time, the fan 15 in the communication pipe 13 has already been driven, and the heater 16 has already been turned on (however, the heater 16 is turned on while driving the fan 15 to circulate the wind). The wind is blown into the furnace from the opening 12 on the lower side of the curing furnace 1,
The inside of the curing furnace 1 is in a state where the temperature is stable. That is, the mold jig 2 filled with the thermosetting resin 35
Is supplied into a curing furnace 1 which is heated and has a stable temperature.

The control of the heating plate 3 is performed based on the result of measuring the temperature of the heating plate 3 by the thermocouple 5.
In this case, as shown in FIG. 2, since the bottom side of the mold jig 2 directly contacts the heating plate 3, the bottom side 22a of the resin filling portion 22 can be heated preferentially.

The hot air blown into the curing furnace 1 is
As shown in FIG. 1, in order to accelerate the resin curing from the surface of the thermosetting resin 35a to be the lens surface 36, the air guide plate 1
It is guided to the bottom side of the mold jig 2 by 7 and 17 and flows upward along the side surface from the bottom of the mold jig 2 to form the top wall after warming the upper side of the resin filling portion 22 as well. The air is sucked from the opened opening 11 and returns to the inside of the communication pipe 13 again.

At this time, the temperature of the hot air sucked from the opening 11 is detected by the sensor 14, and the heater 16 is turned on and off based on the detected temperature, so that the mold jig 2 is constantly controlled. Supply a constant temperature hot air.

By adopting such a hot air circulation system, the temperature distribution in the curing furnace 1 can be stabilized. In addition, by providing the heating plate 3 having a high heat capacity in the curing furnace 1, heat escape due to opening and closing a door (not shown) of the curing furnace 1 can be prevented. In addition, having the heating plate 3 having a high heat capacity in the curing furnace 1 is the same as obtaining a high heat insulating property in the curing furnace 1, and there is little loss due to escape of heat and high curing efficiency. Furnace 1 is obtained.

As described above, in addition to the direct heating of the mold jig 2 by the heating plate 3, a circulation path of hot air (indicated by a white arrow in FIG. 1) is formed, and the inside of the resin filling portion 22 is formed. The thermosetting resin 35 is cured, but is heated preferentially from the bottom side 22a of the resin filling portion 22 as described above, so that the thermosetting resin on the bottom side (semicircular portion) 22a of the resin filling portion 22 is formed. The resin curing is promoted from the surface of the conductive resin 35a.

That is, according to the curing device of the present embodiment,
Since the curing of the thermosetting resin 35 filled in the resin filling portion 22 of the mold case 21 is accelerated from the surface portion of the thermosetting resin 35a located at the lower part in the resin filling portion 22, the resin is hardened. The curing shrinkage occurs on the liquid surface side of the thermosetting resin 35 filled in the resin filling section 22 and the lens surface 36
The surface portion of the thermosetting resin 35a is formed in a clean semicircular shape. FIG. 3 shows the LED lamp after molding.

FIGS. 4 and 5 show an example in which the liquid thermosetting resin curing device of the present invention is applied to a conveyor curing furnace type.

This curing device is provided with a conveyor 7 for curing a resin while conveying a mold jig 2 in a curing furnace 1. The heating plates 3, 3, ...
The driving pulley 71 and the driven pulley 72 of the conveyor 7
Is attached to the transport chain 73 wound around. The driving motor 7 linked to the driving pulley 71
By driving the transport chain 73 by the rotational drive of the heating plate 4, the heating plates 3
.. Sequentially move in the curing furnace 1 in a certain direction (the direction indicated by the arrow A in FIG. 5).

In this case, since the heating plates 3, 3,... Are attached to the transport chain 73 and move, the heaters 4 for heating and controlling the temperature of the heating plate 3, as in the embodiment shown in FIG. Or thermocouple 5 cannot be embedded. That is, the wiring is entangled by the movement. Therefore, in the present embodiment, the transport chain 7 located on the upper side is
3, far-infrared heaters 8, 8 at a certain interval
Are used as heat sources for heating the heating plates 3, 3,.... In this case, in order to efficiently guide the far infrared rays to the heating plates 3, 3,..., The reflecting plates 9, 9,...
・ It is provided.

The thermocouple 10 for measuring the heating temperature of the heating plates 3, 3,... Is arranged at a position in contact with the heating plates 3, 3,. In this case, the thermocouple 10
It is necessary to arrange it so that it is not caught by Further, as a means for preventing the catch, the support arm 10a supporting the thermocouple 10 is allowed to freely swing in the direction shown by the arrow B in FIG. That is, the thermocouple 10 measures the temperature of the heating plate 3 while swinging like a pendulum in a direction indicated by an arrow B in FIG. 5 by sliding contact with the upper surface of the heating plate 3.

In FIG. 5, the thermocouple 10 is shown only at the position immediately before the transfer chain 73 exits from the curing furnace 1, but actually controls the far infrared heaters 8, 8,... Each far-infrared heater 8,
・ ・ Each one is attached to the upper part of. When a loader or unloader is connected to the curing furnace 1, a fully automatic curing furnace can be realized.

Since the other structure is the same as the structure of the curing device shown in FIG. 1, the same members are denoted by the same reference numerals, and the detailed description is omitted. However, in FIG. 5, the circulation path of the warm air is provided at two places in the traveling direction of the heating plates 3, 3,... (That is, the traveling direction of the mold jigs 2, 2,...). May be appropriately provided at a place where temperature measurement is desired, and the number thereof is determined by the length of the conveyor 7. For example, there is a six-zone type in which the conveyor 7 is divided into six zones along the traveling direction and a circulation path is provided for each of the divisions.

Incidentally, the curing time of the thermosetting resin is about 90.
In the case of a batch type oven, the breakdown is [starting up (furnace temperature set value reaching time) 50 minutes + holding (holding time after furnace temperature reaching) 40 minutes = 90 minutes], and curing using the heating plate 3 In the case of a furnace, [26 minutes rise + 64 minutes hold = 9
0 minutes]. In other words, the curing furnace using the heating plate 3 can shorten the rise time by 24 minutes. Therefore, if the holding time in the case of the curing oven using the heating plate 3 is set to 40 minutes as in the case of the batch type oven, the curing time as a whole is 66 minutes and 24 minutes (= 90−6).
6) It can be shortened.

The heater 4 for heating and the heater 16 for circulating hot air shown in FIG. 1, and the far-infrared heater 8 shown in FIG. 5 and the heater 16 for circulating hot air shown in FIG. Each can be controlled separately. This makes it possible to cure the resin under conditions in which there is a difference between the temperature of the heating plate 3 and the ambient temperature in the curing furnace 1. By operating only the heater 4 and the far-infrared heater 8 and intensively heating only the lower surface of the mold jig 2, the upper and lower surfaces of the thermosetting resin are cured with a temperature difference. Is also possible. Further, the heater 4 and the far-infrared heater 8 are not used, and only the hot air circulation is used, and a usage like a conventional conveyer curing oven can be performed.

[0041]

According to a first aspect of the present invention, there is provided a liquid thermosetting resin curing apparatus, comprising a mold jig filled with a liquid thermosetting resin in a state where a light emitting element mounted on a lead frame is inserted. A heating plate for directly contacting and heating a lower surface of a mold jig installed in a curing furnace; and a heating unit for heating the heating plate, and heating the heating plate by the heating unit to form a mold jig. Is heated directly to cure the filled thermosetting resin, so that it can be supplied preferentially to the place where hot air is to be supplied, and the heating jig has a small heating loss so that the mold jig can reach the furnace temperature. The time to reach can be shortened. In addition, since a heating plate having a high heat capacity is provided in the curing furnace, heat escape due to opening and closing the door of the curing furnace can be prevented. Also,
By providing a heating plate having a high heat capacity in the curing furnace, a high heat insulating property can be obtained in the curing furnace, so that a loss due to escape of heat is small and a curing furnace with high thermal efficiency can be realized.

According to a second aspect of the present invention, there is provided an apparatus for curing a liquid thermosetting resin according to the first aspect, wherein the hot air is circulated from a lower side to an upper side in the hardening furnace. Since the circulation means is provided, the temperature distribution in the furnace can be kept stable.

According to a third aspect of the present invention, there is provided an apparatus for curing a liquid thermosetting resin according to the first or second aspect, wherein the heat capacity of the heating plate is set to be at least twice the heat capacity of the mold jig. Thereby, a temperature drop of the heating plate due to heat exchange can be suppressed.

According to a fourth aspect of the present invention, there is provided a liquid thermosetting resin curing apparatus comprising: a mold jig filled with a liquid thermosetting resin in a state where a light emitting element attached to a lead frame is inserted; A heating plate that directly contacts and heats the lower surface of the mold jig installed in the curing furnace, a far-infrared heater that heats the heating plate, and directs warm air from the lower side to the upper side in the curing furnace. With hot air circulation means to circulate,
By heating the heating plate with the far infrared heater,
Because the mold jig is directly heated to cure the thermosetting resin that is filled, even in a conveyor curing furnace, hot air can be preferentially supplied to the place where hot air is to be supplied, and there is little heating loss Therefore, the time until the mold jig reaches the furnace temperature can be reduced. In addition, by having a heating plate with a high heat capacity in the curing furnace, high heat insulation can be obtained in the curing furnace, so that there is little loss due to escape of heat and a conveyor curing furnace with high thermal efficiency can be realized. it can.

According to a fifth aspect of the present invention, there is provided an apparatus for curing a liquid thermosetting resin according to the second, third or fourth aspect, wherein the heating means or the far-infrared heater and the hot air circulating means are separately provided. Since control is possible, it is possible to cure the resin under a condition in which there is a difference between the temperature of the heating plate and the ambient temperature in the curing furnace. In addition, by operating only the heating means and the far-infrared heater and intensively heating only the lower surface of the mold jig, the resin can be cured by providing a temperature difference between the upper surface and the lower surface of the thermosetting resin. it can. Further, by using only the hot air circulation without using the heating means or the far-infrared heater, the same usage as the conventional conveyor curing furnace can be performed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an example in which a curing device for a liquid thermosetting resin of the present invention is applied to a batch type oven type.

FIG. 2 is a cross-sectional view showing a main part of a step of resin-sealing a semiconductor element using the curing device of the present invention.

FIG. 3 is a front view showing the molded LED lamp.

FIG. 4 is a schematic side view showing an example in which the liquid thermosetting resin curing device of the present invention is applied to a conveyor curing furnace type.

FIG. 5 is a schematic front view showing an example in which the liquid thermosetting resin curing device of the present invention is applied to a conveyor curing oven type.

FIG. 6 is an overall configuration diagram showing a batch-type oven (stand-alone) type as an example of a conventional curing device.

FIG. 7 is an overall configuration diagram showing a conveyer curing furnace type as an example of a conventional curing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Curing furnace 2 Mold jig 3 Heating plate 4 Heater 5, 10 Thermocouple 7 Conveyor 8 Far infrared heater 13 Communication pipe 15 Fan 16 Heater 17 Wind guide plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/56 B29C 35/08

Claims (5)

(57) [Claims] 1. A method in which a light-emitting element mounted on a lead frame is inserted and a mold jig filled with a liquid thermosetting resin is directly in contact with a lower surface of the mold jig installed in a curing furnace. And a heating means for heating the heating plate. The heating means heats the heating plate, thereby directly heating the mold jig and filling the thermosetting resin. A curing device for a liquid thermosetting resin, characterized in that the device is cured. 2. The liquid thermosetting resin curing device according to claim 1, further comprising a hot air circulating means for circulating hot air from a lower side to an upper side in the curing furnace. 3. The temperature drop of the heating plate due to heat exchange is suppressed by setting the heat capacity of the heating plate to be at least twice the heat capacity of the mold jig. Curing device for liquid thermosetting resin. 4. A molding jig filled with a liquid thermosetting resin in a state where a light emitting element attached to a lead frame is inserted, and directly contacts a lower surface of the molding jig installed in a curing furnace. A heating plate for heating the heating plate, a far-infrared heater for heating the heating plate, and a hot-air circulating unit for circulating warm air from a lower side to an upper side in the curing furnace; An apparatus for curing a liquid thermosetting resin, wherein a heating plate is heated to directly heat the mold jig to cure the filled thermosetting resin. 5. The liquid thermosetting resin curing device according to claim 2, wherein the heating means or the far-infrared heater and the hot air circulating means are individually controllable. .