JP3588425B2 - Infrared panel heater for heating mounting substrate and reflow furnace using the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heater used in a reflow furnace or other heating device of an SMT (Surface Mount Technology) line.
[0002]
[Prior art]
In the reflow furnace of the SMT line, the printed circuit board on which the electronic components are mounted and the mold resin are directly heated and soldered. As a heater used in the reflow furnace, a commercially available product having a structure in which a heating element is enclosed in ceramics or a structure in which the heating element is molded with a cement-like material has been used.
[0003]
[Problems to be solved by the invention]
The conventional heater as described above has problems that it is heavy, has a large heat capacity, and is expensive. On the other hand, instead of these heaters, it is conceivable to use a heater (for example, using a ceramic fiber) formed by molding a lightweight substance such as a lightweight castable. However, such a lightweight heater generally has the following problems. There is. That is, the wavelength of infrared light that the printed circuit board easily absorbs is about 5 to 8 μm, while the wavelength of infrared light that the mold resin forming the chip of the electronic component easily absorbs is about 1 to 2 μm. However, a lightweight heater mainly emits infrared rays having a wavelength of about 5 to 8 μm, and hardly emits infrared rays having a wavelength of 1 to 2 μm. For this reason, the temperature rising speed varies depending on the distribution of the mold resin on the mounting board. As a result, the temperature varies depending on the location on the mounting board, and a desirable temperature profile cannot be obtained.
[0004]
In view of the above-mentioned conventional problems, an object of the present invention is to provide a heater that is lightweight and inexpensive and that can uniformly heat a mounting substrate.
[0005]
[Means for Solving the Problems]
The mounting panel heating infrared panel heater of the present invention includes a stainless steel panel having a coating layer on one side having a coating layer for increasing the emissivity of infrared rays, and mica as an electrical insulator, and an insulation provided on the other side of the panel. a plate, provided on the other side of the panel through an insulating plate, about a wavelength depending on the configuration of the integrally embedded and ing and light so as to support the heating element on one surface near the ceramic fiber insulation material 5 A case that mainly emits infrared rays of about 8 μm and hardly emits infrared rays of a wavelength of 1 μm to 2 μm, and has an opening for storing the panel, the insulating plate and the heater in a stacked state, and exposing the one surface of the panel. with the door, before Symbol panel, the heater is heated by the infrared radiation radiated from about 1 including the wavelength of 1~2μm that is hardly radiated from the heater An infrared ray having a wavelength range of μm is to substantially uniformly radiated.
In the infrared panel heater for mounting substrate heating configured as described above, the panel heated by receiving the infrared rays emitted by the heater has a wavelength range of about 1 to 8 μm including a wavelength of 1 to 2 μm, which is hardly radiated from the heater. Irradiates the infrared rays substantially uniformly. This allows the panel to emit infrared light that includes both a wavelength that is easily absorbed by the printed circuit board and a wavelength that is hardly emitted from the heater and that is easily absorbed by the mold resin of the electronic component. Therefore, when the infrared panel heater is used in a reflow furnace or the like, the printed board and the electronic components of the mounting board are uniformly heated, and the entire board is uniformly heated.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an exploded perspective view showing a configuration of an infrared panel heater 10 according to one embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the infrared panel heater 10. 1 and 2, an infrared panel heater 10 includes a metal IR (infrared) panel 3 and an insulating plate 4 in a rectangular parallelepiped case configured by combining an upper cover 1 and a lower cover 2 in a lunch box shape. And 5, and a ceramic fiber integral molded heater (hereinafter simply referred to as a heater) 6 are housed in a stacked state in this order.
[0007]
The IR panel 3 is a stainless steel plate, and an IR coating layer 3a for increasing the emissivity of infrared rays is formed on one surface, that is, on the lower surface in the drawing. The insulating plates 4 and 5 are made of mica as an electrical insulator. The insulating plate 4 is arranged below the heater 6, and the pair of insulating plates 5 are arranged on both side surfaces of the heater 6. These insulating plates 4 and 5 are provided for electrical insulation with the IR panel 3 and the lower cover 2, respectively. The heater 6 is integrally buried by vacuum molding so as to support a coil-shaped heating element 6a near one surface (lower surface) of the ceramic fiber heat insulating material. Both ends of the heating element 6a are led out from holes (not shown) provided in the upper cover 1. The bottom surface of the lower cover 2 has a rectangular opening 2a, and the IR coating layer 3a of the IR panel 3 is exposed from the opening 2a. It is preferable that the lower surface of the lower cover 2 is also coated with IR. This is because the soaking degree is further improved. The mounting board 7 on which the electronic components are mounted on the printed board is disposed below the infrared panel heater 10 in FIG. 2 and is heated.
[0008]
In the infrared panel heater 10 configured as described above, the IR panel 3 is heated by receiving the infrared rays emitted by the heater 6. Thus, the IR panel 3 emits infrared light. The mounting board 7 is heated by infrared rays emitted from the IR panel 3. Since the heater 6 has the coil-shaped heating element 6a, the heat distribution on the lower surface of the heater 6 is not always uniform, but the heat distribution is averaged by the IR panel 3 via the insulating plate 4, and the lower surface of the IR panel 3 A substantially uniform heat distribution is obtained throughout.
FIG. 3 is a graph showing a spectrum of infrared rays emitted from the IR panel 3. As shown in the figure, it can be seen that infrared rays having a wavelength of about 1 to 8 μm are emitted substantially uniformly. Although the heater 6 hardly emits infrared rays having a wavelength of 1 to 2 μm, such a result is obtained by emitting infrared rays of about 1 to 8 μm including this range as a secondary wavelength emitted from the IR panel 3. .
[0009]
Of the infrared rays radiated from the infrared panel heater 10 in this manner, infrared rays having a wavelength of about 1 to 2 μm are mainly absorbed by the mold resin of the electronic component. Further, infrared rays having a wavelength of about 5 to 8 μm are mainly absorbed by the printed circuit board. Therefore, the mounting substrate 7 is uniformly heated as a whole, and there is no variation in temperature, so that a desired temperature profile can be obtained. Further, since the heater 6 is lightweight and relatively easy to manufacture, the entire infrared panel heater 10 can be provided at a low weight and at a low cost.
[0010]
Although the IR panel 3 and the lower cover 2 can be formed integrally, it is preferable to use separate members as in the above embodiment from the viewpoint of preventing distortion due to heat. Further, the infrared panel heater 10 configured as described above is particularly suitable for heating not only a printed board but also an object to be processed having similar infrared absorption characteristics. Therefore, the infrared panel heater 10 can be applied to a heating device other than a reflow furnace.
[0011]
【The invention's effect】
The present invention configured as described above has the following effects.
According to the mounting panel heating infrared panel heater of the present invention, the panel is heated by receiving infrared rays emitted by a heater that mainly emits infrared rays having a wavelength of about 5 to 8 μm and emits little infrared rays having a wavelength of 1 to 2 μm. Accordingly, the panel emits infrared light having a wavelength of about 5 to 8 μm, which is easily absorbed by the printed circuit board, and a wavelength of 1 to 2 μm, which is hardly emitted from the heater and easily absorbed by the molding resin of the electronic component. Therefore, if the infrared panel heater is used in a reflow oven or the like, the printed board and the electronic components of the mounting board are uniformly heated, and the entire board is uniformly heated, so that the temperature profile is improved. In addition, since the heater is lightweight and relatively easy to manufacture, it is possible to provide the entire infrared panel heater lightly and inexpensively.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view illustrating a configuration of an infrared panel heater according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of the infrared panel heater.
FIG. 3 is a graph showing a spectrum of the infrared panel heater.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper cover 2 Lower cover 2a Opening 3 IR panel 3a IR coating layer 4,5 Insulating plate 6 Heater (Ceramic fiber integral molding heater)
6a Heating element 10 Infrared panel heater

Claims (2)

A stainless steel panel with a coating layer on one side that increases the emissivity of infrared rays,
An insulating plate made of mica as an electrical insulator, provided on the other surface side of the panel,
Through said insulating plate provided on the other surface side of the panel, heating element by the configuration of the integrally embedded and ing and light so as to support one surface near the ceramic fiber insulation material having a wavelength of about 5~8μm A heater that mainly emits infrared light and hardly emits infrared light having a wavelength of 1 to 2 μm ;
A case having an opening for storing the panel, the insulating plate and the heater in an overlapping state, and exposing the one surface of the panel ,
Before Symbol panel, the heater is heated by the infrared radiation emitted, and wherein the substantially be uniformly emits little infrared wavelength range of about 1~8μm having wavelengths 1~2μm not radiated from the heater Infrared panel heater for mounting board heating . In a reflow furnace in which a heating target on which electronic components are mounted is heated by an infrared panel heater and soldered, the infrared panel heater includes:
A stainless steel panel with a coating layer on one side that increases the emissivity of infrared rays,
An insulating plate made of mica as an electrical insulator, provided on the other surface side of the panel,
Through said insulating plate provided on the other surface side of the panel, heating element by the configuration of the integrally embedded and ing and light so as to support one surface near the ceramic fiber insulation material having a wavelength of about 5~8μm A heater that mainly emits infrared light and hardly emits infrared light having a wavelength of 1 to 2 μm ;
A case having an opening for storing the panel, the insulating plate and the heater in an overlapping state, and exposing the one surface of the panel ,
Before Symbol panel, the heater is heated by the infrared radiation emitted, and wherein the substantially be uniformly emits little infrared wavelength range of about 1~8μm having wavelengths 1~2μm not radiated from the heater Reflow furnace.

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