JP2022165405A - Radiation shield structure for electronic device - Google Patents

Abstract

To provide radiation resistance by surely shielding exposure of radiation to an electronic device in a state where the electronic device is mounted on a substrate.SOLUTION: A radiation shield structure for an electronic device comprises: a first shield cover which is molded into a shape covering the electronic device mounted on a front face of a wiring board with a radiation shield material when shielding the electronic device mounted on the wiring board from radiation, and of which a whole edge is soldered to the wiring board; a second shield cover which is molded into a shape covering a rear face of the wiring board in a location where the electronic device is mounted, with a radiation shield material, and of which the whole edge is soldered to the rear face of the wiring board; a first junction pattern region formed from a copper foil in a region where the whole edge of the first shield cover is soldered, in the wiring board at a front face side of the wiring board and around the location where the electronic device is mounted; and a second junction pattern region formed from a copper foil in a region where the whole edge of the second shield cover is soldered, at a rear face side of the wiring board.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to radiation shielding structures for electronic devices.

In recent years, in the space industry, businesses using small satellites by venture companies have been launched. In such a business, the electronic devices (including electronic equipment) used in small satellites are marketed as COTS (Commercial Off-The-Shelf) because it takes time and cost to develop them for space. There is an increasing use of commercially available and off-the-shelf products.

However, commercial products and off-the-shelf products are not designed with anti-space environments in mind, and do not guarantee resistance to radiation such as gamma rays. For this reason, a process is provided in which the electronic devices to be used are exposed to radiation in advance using a radiation irradiation facility, and screening is performed to determine the degree of performance deterioration and failure.

Furthermore, in the design of satellite mounting, heavy metals (for example, tungsten and lead) with shielding effects are used to provide enclosures and shielding structures for housing electronic devices, substrates, and the like.

Japanese Patent Publication No. 2006-518112 Japanese Patent Publication No. 2007-531981 JP-A-2002-166899

3rd Space Seminar "Space environment for spacecraft design", Japan Aerospace Exploration Agency, Haruhisa Matsumoto, May 8, 2015, Kyoto University Museum, 3rd floor lecture room

By the way, when an electronic device is used in a space environment, the die, which is a semiconductor (silicon, etc.) enclosed in the package of the electronic device, is exposed to radiation, especially gamma rays containing charged particles. become.

When exposed to radiation, permanent damage and performance degradation due to potential fluctuations in the die, called the total dose effect, as well as temporary malfunction of electronic devices due to charged particles passing through the die, called the single event effect occurs and causes satellite malfunction.

Therefore, the present embodiment aims to provide a radiation shielding structure for an electronic device that can reliably shield the electronic device from being exposed to radiation while the electronic device is mounted on a substrate, thereby imparting radiation resistance. and

A radiation shielding structure for an electronic device according to this embodiment includes a first shielding cover and a second shielding cover for shielding an electronic device mounted on a wiring board from radiation. The first shielding cover is shaped to cover the electronic device mounted on the surface of the wiring board with a radiation shielding material, and the entire edge is soldered to the wiring board. Also, the second shielding cover is formed in a shape that covers the rear surface of the wiring board where the electronic device is mounted with the radiation shielding material, and the entire edge is soldered to the rear surface of the wiring board. On the other hand, the wiring substrate is provided with a first bonding pattern area and a second bonding pattern area of copper foil. The first bonding pattern area is formed on the surface side of the wiring board in the area where the entire edge of the first shielding cover is soldered around the mounting location of the electronic device. Also, the second joint pattern area is formed in the area where the entire edge of the second shielding cover is soldered on the back side of the wiring board.

1A and 1B are a top view and a cross-sectional view showing a radiation shielding structure for an electronic device according to a first embodiment. FIG. 2 is a cross-sectional view showing a radiation shielding structure for an electronic device according to a second embodiment. FIG. 3 is a top view showing the radiation shielding structure of the electronic device according to the second embodiment. FIG. 4 is a plan view showing a specific arrangement example of through holes applied to the radiation shielding structure for an electronic device according to the second embodiment. FIG. 5 is a cross-sectional view showing how radiation is incident when shielding is not sufficient due to restrictions in the structure of the first embodiment. 6A and 6B are a top view and a cross-sectional view showing the radiation shielding structure of the electronic device according to the third embodiment. FIG. 7 is a cross-sectional view of the structure of the third embodiment for explaining adverse effects caused by a closed space. 8A and 8B are a top view and a cross-sectional view showing a radiation shielding structure for an electronic device according to a fourth embodiment. FIG. 9 is a cross-sectional view showing a radiation shielding structure for an electronic device according to a fifth embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION (hereinafter simply referred to as embodiment) for carrying out the present invention will be described in detail below with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art will naturally include within the scope of the present invention any suitable modifications that can be easily conceived while maintaining the gist of the invention. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual embodiment, but this is only an example and does not apply to the present invention. It does not limit interpretation. In addition, in this specification and each figure, the same reference numerals are given to components that exhibit the same or similar functions as those described above with respect to the previous figures, and redundant detailed description may be omitted as appropriate. .

As described above, when an electronic device is used in a space environment, the die, which is a semiconductor enclosed in the package of the electronic device, is exposed to radiation, particularly gamma rays having charged particles.

When exposed to radiation, permanent damage and performance degradation due to potential fluctuations in the die, called the total dose effect, as well as temporary malfunction of electronic devices due to charged particles passing through the die, called the single event effect occurs and causes satellite malfunction.

In order to improve the radiation exposure of such semiconductors, conventionally, a structure in which a single semiconductor device has a shielding effect has been proposed, as disclosed in Patent Documents 1 and 2. However, not all electronic devices are compatible with these techniques, and many of them are expensive and not commercially available.

Recently, in the packaging of electronic devices, it is called a QFP (Quad Flat Package) package, in which external connection terminals for electrically connecting the die in the device to an external circuit, power supply, and ground are drawn out from all four sides of the package. A BGA (Ball Grid Array) package, in which external connection terminals are arranged in a grid pattern on the bottom of the package, is the mainstream.

With the miniaturization of devices, the arrangement intervals of the external terminals themselves are on the order of 1 to 0.1 mm, such as 0.65 mm, making it extremely difficult to implement shielding measures for the device alone.

Therefore, in the following description, an embodiment in the case of a QFP (Quad Flat Package) package and an embodiment in the case of a BGA (Ball Grid Array) package will be taken up.

(First embodiment)
FIG. 1 shows a radiation shielding structure for an electronic device according to a first embodiment, where (a) is a top view and (b) is a cross-sectional view. In FIG. 1, 11 is an electronic device in a QFP package, 12 is a wiring board on which the electronic device 11 is mounted, 131 and 132 are bonding pattern areas made of copper foil, 14 is a through hole, and 151 and 152 are shielding covers made of lead. . 1(a) shows a transparent cover 151 from above the mounting surface of the electronic device 11, and FIG. 1(b) shows a cross section of the mounting surface of the wiring board 12 viewed from the side. ing.

As shown in FIGS. 1(a) and 1(b), an electronic device 11 has a die 111 housed in a package 112 made of a molding material, and a plurality of external connection terminals 113 drawn out from the four sides of the package 112 at predetermined intervals. Configuration.

The wiring board 12 has a structure in which a wiring path is formed inside. A land 121 for connection is formed at a position facing the terminal 113 at the mounting position of the electronic device 11, and a ground layer 122 is formed in the board. be. In the wiring board 12, bonding pattern areas 131 and 132 made of copper foil (pad) are provided around the front surface of the mounting position of the electronic device 11 and around the opposite back surface so as to face each other. Through holes 14 are formed at predetermined intervals between the copper foils of the bonding pattern regions 131 and 132 . Through hole 14 is connected to ground layer 122 formed inside wiring board 12 .

The upper shielding cover 151 has a shape in which the edge faces the bonding pattern area 131 formed on the surface of the wiring board 12 , covers the electronic device 11 from above, and has the edge bonded to the bonding pattern area 131 . is fixed by soldering. In addition, the lower shielding cover 152 has a shape in which the edge faces the joint pattern area 132 formed on the back surface of the wiring board 12, and is fixed by soldering while the edge is joined to the joint pattern area 132. be done.

For example, in the present embodiment, the shielding covers 151 and 152 use lead, which is easy to process, as a radiation shielding material. Lead has affinity with solder used when mounting the electronic device 11 on the wiring board 12, and has a high shielding property by soldering.

In the wiring board 12 on which the electronic device 11 is mounted, the shielding covers 151 and 152 made of lead are placed on the front surface and the rear surface of the substrate around the mounting position of the electronic device so that the electronic device 11 is surrounded by the shielding covers 151 and 152. , 152 can be directly soldered, bonding pattern areas 131 and 132 are formed by copper foil (pad).

After the electronic device 11 is mounted on the wiring board 12, the shielding covers 151 and 152 are soldered to the bonding pattern regions 131 and 132 of the wiring board 12, thereby firmly fixing the shielding covers 151 and 152. FIG.

As a result, when the electronic device 11 is mounted on the wiring board 12, the radiation is shielded from both the front side and the back side, and the exposure of the electronic device to the radiation is reliably shielded to improve the radiation resistance. can have.

In addition, in this embodiment, between the bonding pattern regions 131 and 132 formed of copper foil (pads) for fixing the shielding covers 151 and 152, predetermined through holes 14 for connecting to the ground layer 122 provided on the wiring board 11 are provided. A large number are formed at intervals of . According to this structure, the shielding covers 151 and 152 soldered to the joint pattern regions 131 and 132 themselves have the same potential as the ground layer. Therefore, a current leak path is formed, and in addition to the radiation shielding effect, the electronic device 11 is prevented from being charged.

In addition, heat generated by the electronic device is transmitted to the shielding covers 151 and 152 via the ground layer 122 and the through holes 14 of the wiring board 12, so that a heat dissipation effect can be obtained. Further, regarding the shielding covers 151 and 152, in addition to closely contacting the package 112 of the electronic device 11, by increasing the bonding area with the bonding pattern regions 131 and 132 and the number of through holes 14, the heat dissipation effect can be improved. be.

(Second embodiment)
FIG. 2 is a cross-sectional view showing a radiation shielding structure for an electronic device according to the second embodiment, FIG. 3 is a top view of the structure viewed from above, and FIG. 4 is a through hole of the same embodiment. It is a top view showing an example of arrangement. 2 to 4, the same parts as in FIG. 1 are denoted by the same reference numerals, and different parts will be described here.

2 to 4, reference numeral 16 denotes a large number of through holes formed in the wiring board 12. As shown in FIG. Reference numerals 171 and 172 denote shielding plates made of tungsten, which has a radiation shielding rate six times higher than that of lead. The shielding plate 171 is arranged between the upper surface of the package 112 of the electronic device 11 and the inner upper surface of the shielding cover 151 to face them. Also, the shielding plate 172 is arranged between the rear surface of the wiring board 12 and the inner bottom surface of the lower shielding cover 152 so as to face both. In this way, while the shielding plates 171 and 172 made of tungsten are interposed so as to sandwich the electronic device 11 and the wiring board 12 , the shielding covers 151 and 152 are attached to the bonding pattern regions 131 and 131 of the wiring board 12 . By soldering to 132, the shielding plates 171 and 172 made of tungsten, which is difficult to process, can be easily fixed, thereby realizing a further shielding effect. It should be noted that the shielding effect can be obtained with either one of the shielding plates 171 and 172 .

In addition, in the present embodiment, the wiring substrate 12 is formed with a large number of through holes 16 in a staggered pattern not only in the bonding pattern regions 131 and 132 but also in the vicinity of the electronic device, and the through holes 16 are filled with solder. do. As a result, it is possible to reduce the amount of radiation incident from the side surface of the wiring substrate 12 reaching the die 111 at the radiation incident portion in FIG. 2, thereby improving the radiation resistance.

Specifically, the through holes 16 are arranged, for example, as shown in FIG. That is, in a lattice shape in which the sides of a plurality of hexagons are brought into close contact with each other, each through-hole 16 is arranged with its midpoint aligned with each apex and center point of the hexagon as a reference point. Furthermore, the radius r of the hole diameter of each through hole 16 is set to 1/4 or more of the hexagonal side α. As a result, a path larger than the hole diameter can always be passed through, and a certain amount of attenuation can be guaranteed.

Also, from the ratio of the lead content of the solder that fills the through holes 16, for example, if the lead content is 60% and the thickness of the lead plate that can be expected to have a radiation attenuation effect is 3 mm, the total hole diameter of the through holes 16 will be doubled. The number of through holes may be increased so as to obtain 6 mm of .

(Third Embodiment)
FIG. 5 is a cross-sectional view of the structure of the first embodiment, showing how radiation is incident when shielding is not sufficient due to restrictions. FIG. The radiation shielding structure of the electronic device concerned is shown, (a) is a top view, (b) is sectional drawing. 6(a) shows a transparent state through the shielding cover 151 from above the mounting surface of the electronic device 11, and FIG. 6(b) shows a cross section of the mounting surface of the wiring board 12 viewed from the side. ing. 5 and 6, the same parts as in FIG. 1 are denoted by the same reference numerals, and different parts will be described here.

In the first embodiment shown in FIG. 1, a large number of through holes 14 filled with solder are provided in the substrate 12 to shield the incidence of radiation from the outside. , board area, high pattern density for signal wiring, etc., it is conceivable that sufficient through holes 14 for shielding cannot be arranged. In this case, as shown in FIG. 5, the radiation is incident on the die 111 from the side surface of the wiring substrate 12 at the point where the radiation is incident from the obliquely downward direction in the drawing, on the surface opposite to the surface on which the electronic device 11 is mounted. However, it is difficult to secure the radiation shielding effect that

Therefore, in the third embodiment, as shown in FIG. It is made wider than the opposing range of the shielding area by the shielding cover 151 and the joint pattern area 131 arranged on the upper side in the figure. A plurality of through holes 141 are formed in the bonding pattern region 131 on the mounting surface side of the substrate 12 and connected to lands 133 formed on the back surface side. A plurality of through holes 142 are also formed in the bonding pattern region 132 on the back side of the substrate 12 and connected to the lands 134 formed on the front side. According to this structure, the shielding range of the shielding cover 152 arranged on the back surface of the wiring board 12 is a wider range than the opposing surface of the shielding range of the shielding cover 151 arranged on the front surface of the wiring board 12. Even if through holes cannot be arranged, it is possible to shield the radiation incident on the die 111 from the obliquely downward direction of the wiring board 12 .

(Fourth embodiment)
FIG. 7 is a structure of the third embodiment, and is a cross-sectional view for explaining the adverse effects caused by the closed space. FIG. 8 is an electronic device according to the fourth embodiment, which improves the adverse effects caused by the closed space shown in FIG. (a) is a top view, and (b) is a sectional view. 8(a) shows a transparent state through the shielding cover 151 from above the mounting surface of the electronic device 11, and FIG. 8(b) shows a cross section of the mounting surface of the wiring board 12 viewed from the side. ing. 7 and 8, the same parts as those in FIG. 6 are denoted by the same reference numerals, and different parts will be described here.

When operating electronic devices in a vacuum environment such as outer space, outgassing emitted from organic materials condenses in the vacuum environment and adheres to other devices, especially optical devices, etc., resulting in deterioration of performance. known to have adverse effects. To avoid this, a technique called degassing (vacuum baking) is used. In this method, the target device is exposed to a space evacuated by a vacuum chamber, and heated with a heater to a high temperature to release the gas that is stored inside the material used in the target device in advance. is.

As shown in FIG. 7, in the shielding structure of the third embodiment shown in FIG. 6, a shielding cover 151 and a shielding cover 151 and a shielding cover 151 and a shielding cover 151 are provided in the bonding pattern region 131 on the front side and the bonding pattern region 132 on the back side provided on the wiring board 12, respectively. By soldering the cover 152, sealed spaces 301 and 302 are formed on the front side and the back side, respectively. Depending on the material used in the shielding cover, outgassing may be generated, but since the space is sealed by the shielding, if a small amount of leakage occurs over a long period of time, the electronic device 11 inside the shielding cover will be damaged. It may adversely affect other equipment, including Further, when exposed to an environment where air pressure fluctuations occur, tensile stress or compressive stress is applied to the shielding cover 151, the shielding cover 152, the bonding pattern region 131, the bonding pattern region 132, and the wiring substrate 12, causing breakage or the like. There is also the possibility of doing so.

Therefore, in the present embodiment, as shown in FIG. 8, the internal space 301 formed by the shielding cover 151 and the internal space 302 formed by the shielding cover 152 of the wiring board 12 are connected and ventilated. A hollow through-hole (not filled with solder) 143 is formed in the wiring board 12 and connected to the land 133 formed on the back surface, and between the inner space 302 formed by the shielding cover 152 and the outer space on the front side of the wiring board 12. A hollow through-hole (not filled with solder) 144 is formed at a position for connecting and ventilating, and is connected to a land 134 formed on the surface. In this embodiment, the bonding pattern area 131 on the mounting surface side and the bonding pattern area 132 on the back surface side are each extended inward, and the through holes 143 and 144 are formed in the extended areas. According to this structure, as indicated by the arrows in the figure, between the inner space 301 formed by the shielding cover 151 and the inner space 302 formed by the shielding cover 152 and the outer space, an outgassing path is secured, and under a pressure fluctuation environment, It is possible to prevent the occurrence of tensile stress or compressive stress that occurs in.

(Fifth embodiment)
FIG. 9 is a cross-sectional view showing a radiation shielding structure for an electronic device according to a fifth embodiment. Here, a radiation shielding structure is shown in which an electronic device 21 with a BGA package is mounted on a flexible wiring board 22 . In FIG. 9, the electronic device 21 has a structure in which a die 211 is housed in the mold resin of a BGA package 212, and solder balls as external connection terminals 213 are arranged on the bottom surface of the package 212 in a grid pattern.

In this embodiment, as shown in FIG. 9, a bendable flexible substrate or a rigid flexible substrate is attached to the wiring substrate 22 on which the electronic device 21 is mounted as a means for reliably shielding the entire circumference of the electronic device 21 from incident radiation. use the substrate. The electronic device mounting portion of the wiring board 22 is provided with lands 221 for connecting the external connection terminals 213 of the electronic device 21 to the internal wiring paths.

As a radiation shielding structure, the flexible wiring board 22 on which the electronic device 21 is mounted is covered by a shielding cover 231 formed in a box shape with one side open and made of lead that shields radiation. The electronic device 21 including the bent side surface of the wiring substrate 22 is accommodated from the upper side of the electronic device 21 in a state where the outer side thereof is bent into a mountain fold. In addition, a box-shaped shielding cover is formed by using a shielding block 232 formed in a convex shape so as to secure a gap that is narrower than the opening surface of the shielding cover 231 and that allows the wiring board 22 to be pulled out by lead that shields radiation. The wiring board 22 accommodated in 231 is pressed from the back side.

The wiring board 22 is bent along the edge of the shielding cover 231 into a valley fold. At this time, copper foils 241 and 242 are provided in the bonding area between the wiring board 22 and the shielding cover 231, and the shielding cover 231 is fixed by soldering in a state where the edges thereof are joined to the copper foils 241 and 242. .

In addition, copper foils 251 and 252 are provided at the joint portion of the wiring board 22 with the shielding block 232 , and the shielding block 232 is fixed by soldering in a state of being joined to the copper foils 251 and 252 .

All of the copper foils 241 , 242 , 251 and 252 should be connected to the ground of the wiring board 22 . As a result, the shielding cover 231 and the shielding block 232 are connected by soldering to the ground, so that the electronic device 21 and the wiring board 22 themselves can be prevented from being charged and a heat radiation effect can be obtained.

That is, in the present embodiment, the shield cover is formed in a box shape with one side open, designed to have a depth capable of accommodating the sides of the electronic device 21 and the flexible wiring board 22 on which the electronic device 21 is mounted. 231 covers the upper surface of the electronic device 21, and for the lower surface of the electronic device 21, for example, a convex shape made of lead with a size that can be fitted with the shielding cover 231 on the upper surface with a gap that allows the flexible wiring board 22 to be pulled out is provided. , the portion of the wiring board 22 on which the electronic device 21 is mounted is sandwiched between the box-shaped shielding cover 231 and the convex-shaped shielding block 232 .

As described above, according to the structure of the present embodiment, it is possible to reliably block the incidence of radiation from all around including the incidence of radiation on the die 211 obliquely downward from the end of the wiring board 22 .

Furthermore, since the flexible wiring board 22 with elasticity is used and sandwiched between the shielding cover 231 and the shielding block 232, the tensile stress or compressive stress due to atmospheric pressure fluctuations is absorbed by the elasticity of the flexible substrate and each of the shielding covers 231, 231, and 232. 232, and the effect of securing the outgassing discharge path is exhibited.

In addition, although several shielding structures are used together in the above embodiment, they may be used individually. In addition, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying constituent elements without departing from the gist of the present invention at the implementation stage. Also, various inventions can be formed by appropriate combinations of the plurality of constituent elements disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, components across different embodiments may be combined as appropriate.

DESCRIPTION OF SYMBOLS 11... Electronic device, 111... Die, 112... Package, 113... External connection terminal, 12... Wiring board, 121... Land, 122... Ground layer, 131, 132, 133, 134... Bonding pattern area (copper foil), 14 , 141, 142, 143, 144 through holes 151, 152 shielding cover (lead) 16 through holes 171, 172 shielding plate (tungsten) 21 electronic device 211 die 212 package 213... External connection terminal (solder ball) 22... Flexible wiring board 221... Land 231... Shielding cover (lead) 232... Shielding block (lead) 241, 242, 251, 252... Copper foil 301, 302 …interior space.

Claims (9)

A radiation shielding structure for an electronic device that shields an electronic device mounted on a wiring board from radiation,
a first shield molded into a shape that covers the electronic device mounted on the surface of the wiring board by the radiation shielding material, and having all edges soldered to the wiring board;
a second shield that is shaped to cover the rear surface of the wiring board where the electronic device is mounted by the radiation shielding material, and that has all edges soldered to the rear surface of the wiring board;
A first bonding pattern area made of copper foil formed on the surface side of the wiring board, around the mounting location of the electronic device, in the area where the entire edge of the first shield of the wiring board is soldered. When,
A radiation shielding structure for an electronic device, comprising: a second bonding pattern area of copper foil formed in an area where the entire edge of the second shield is soldered on the back side of the wiring board. 2. The radiation shielding structure for an electronic device according to claim 1, wherein said first joint pattern area and said second joint pattern area are both connected to the ground of said wiring board. The wiring substrate includes a plurality of through holes penetrating and connecting the first bonding pattern region and the second bonding pattern region, and heat generated in the electronic device is transferred through the plurality of through holes to the second bonding pattern region. 2. A radiation shielding structure for an electronic device according to claim 1, transmitting to one shield and said second shield. interposed between the electronic device and the first shield and/or between the surface of the wiring substrate facing the mounting position of the electronic device and the second shield, 2. The radiation shielding structure for an electronic device according to claim 1, further comprising a shielding plate made of a shielding material having a shielding rate higher than that of said second shielding member and said second shielding member. 2. A radiation shield for an electronic device according to claim 1, wherein a plurality of through-holes are densely arranged in the vicinity of the mounting position of said electronic device on said wiring board, and solder is filled into each hole of said plurality of through-holes. structure. In a lattice shape in which sides of a plurality of hexagons are brought into close contact with each other, each vertex of the plurality of hexagons and a center point of the plurality of hexagons are set as reference points, and the center point of the through holes is set as the reference point. are formed on the wiring board according to the points, and the radius of each of the plurality of through holes: r is set to 1/4 or more of the side of the hexagon: α, and a certain amount of 2. The radiation shielding structure for an electronic device according to claim 1, which ensures an attenuation effect. 2. The electronic device according to claim 1, wherein the shielding range of said second shield arranged on the back surface of said wiring board is wider than the shielding range of said first shield arranged on the front surface of said wiring board. Radiation shielding structure for the device. A first internal space formed by the first shield on the front side of the wiring board and a second internal space formed by the second shield on the back side of the wiring board are connected. A hollow through-hole is formed in the wiring board at a position where the air is ventilated and a position where the second internal space and the external space on the surface side of the wiring board are connected to each other and the air is vented. 8. The radiation shielding structure for an electronic device according to claim 7, wherein The wiring board is made of a flexible material,
The first shield is formed in a box shape with one side open by the shielding material for shielding the radiation, and the wiring board on which the electronic device is mounted is mounted on the outside of the mounting range of the electronic device. In a folded state, the electronic device is accommodated from the upper side including the folded side surface of the wiring board,
The second shield is formed in a convex shape narrower than the opening surface of the first shield by the shielding material for shielding the radiation, and the wiring substrate housed in the first shield is viewed from the rear surface side. 2. The radiation shielding structure of an electronic device as claimed in claim 1, wherein said convex upper surface is housed inside said first shield.

Images