JPH0964582A - Shield case structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make uniform the quantity of heat being generated from a device over the surface thereof by fixing an independent metal piece to a part of the surface of a shield case and projecting planar parts, in parallel with each other, from the surface of the shield case and the surface of a circuit board. SOLUTION: A heating device 3 is mounted on a circuit board 6 and brought into contact with an independent metal piece 1 having a planar part 5 formed on the shield case plane 2. This structure prevents the temperature in a unit from increasing over an allowable limit due to the heating device 3. When the position and the number of independent metal pieces 1 are set appropriately depending on the number, the quantity of heat and the mounting position of heating device 3, the shield case plane 2 can be used commonly. Since it is not required to prepare a machining die of the shield case for every product, rationalization can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield case structure used for assembling a tuner of a television receiver or a high speed digital signal processing circuit unit.

[0002]

2. Description of the Related Art Since a conventional typical electromagnetic wave shield structure, for example, a circuit block constituting a high-speed digital signal processing circuit of a television receiver handles high frequency components, mutual interference (crosstalk) between adjacent circuit blocks. As a typical example of the preventive measure (1), there is a form in which the circuit board is covered with a shield case.

[0003]

In this case, if a mounted component on the circuit board has a heating element of relatively high power consumption, heat is trapped in the shield case and the temperature rises to a high limit of the heat resistance of the mounted component. I rarely cross over. In such a case, there is a risk that performance and reliability during use may be impaired. Further, when the allowable limit value is exceeded, there is a drawback that the cost of parts such as a heat sink for heat radiation and the cost of mounting become high. Further, since the heat sink is attached, the volume of the shield case of the unit becomes large, and the atmospheric temperature in the shield case is hardly lowered.

The present invention solves the above-mentioned problems of the prior art, and the amount of heat from a heat-generating component is directly and quickly conducted to the surface of the heat-generating component and directly to a projecting flat portion that is in contact with the maximum area. By conducting heat to the case and further dissipating the heat from the surface of the shield case to the outside of the shield case, the effect of suppressing the temperature inside the shield case to a relatively low level is enhanced.

[0005]

In order to efficiently conduct heat from the heat-generating component to the shield case, it is necessary to maximize the contact area with the heat-generating component.

In this case, since the contact with the surface of the heat-generating component is uniform over the entire contact surface, the heat conduction efficiency becomes high. Therefore, it is necessary that the peripheral portion of the plane contact portion be freely deformed.

In the configuration of the present invention, the amount of heat generated from the surface of the heat-generating component on the circuit board is efficiently conducted to the shield case by direct conduction, thereby minimizing the temperature rise of the air in the shield case. It will be realized.

Further, when the position of the heat-generating component is limited, the protrusion which comes into contact with the heat-generating component is not formed as a separate piece, but a part of the shield case is expanded to form a protrusion.

[0009]

As a result, a heat sink or the like for radiating heat is not required, so that the cost of parts and the installation cost can be rationalized, and the unit can be designed thin. Further, the position of the heat-generating component of the circuit board differs depending on the product, but the position of the heat-generating component is not limited by forming a separate piece in contact with the heat-generating component. As a result, the shield case is a means to have the advantage that it can be commonly used even for products having different heat-generating component positions.

[0010]

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

(Embodiment 1) Sectional views 1 and 2 of a shield case structure according to an embodiment of the present invention are side views of the essential portions of FIG. In the figure, reference numeral 1 is a metal separate piece having a flat surface forming portion that comes into contact with a heat generating component. 2 is the shield case surface parallel to the circuit board. 3 is a heat-generating component mounted on the circuit board. Reference numeral 4 is an L-shaped projection forming portion for attachment to the shield case provided on the metal separate piece 1. Reference numeral 5 is a plane forming portion that comes into contact with the heat generating component. 6 is a circuit board. 7 is a hole of a shield case provided for fitting the L-shaped projection forming portion and for heat dissipation.

(Embodiment 2) A shield case structure according to an embodiment of the present invention is shown in FIGS. FIG. 3 is a plan view of a protrusion forming piece to be brought into contact with a heat generating component according to one embodiment of the present invention, and FIG. 4 is a main part in a state where the protrusion forming piece to be brought into contact with a heat generating component according to one embodiment of the present invention is attached to a shield case. A sectional view is shown. In this case, a separate metal piece having a convex flat surface forming portion that comes into contact with the heat generating component is integrated with the shield case. Needless to say, the flat surface of the shield case parallel to the circuit board may be formed by drawing.

[0013]

By using the shield case structure of the present invention as a circuit mounting unit, it is possible to prevent the temperature inside the unit from rising above an allowable limit due to heat-generating components. Also,
The shield case can be commonly used by appropriately setting the position and the number of separate metal pieces according to the number of heat-generating components, the amount of heat, and the mounting position. As a result, a great rationalization can be achieved, such as eliminating the need to manufacture a processing case for the shield case for each product.

[Brief description of drawings]

FIG. 1 is a sectional view of a shield case structure according to an embodiment of the present invention.

FIG. 2 is a side view of a protrusion forming piece according to an embodiment of the present invention.

FIG. 3 is a plan view of a projection forming piece according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of an essential part of a state where the protrusion forming piece according to the embodiment of the present invention is attached to the shield case.

[Explanation of symbols]

 1 Heat-dissipating metal contact piece 2 Shield case flat surface 3 Heat-generating component 4 L-shaped projection piece 5 Flat surface forming part 6 Circuit board 7 hole

Claims (4)

[Claims] 1. A metal shield case which encloses a circuit board and shields against electromagnetic interference, wherein a separate metal piece is attached to a part of the shield case surface and is parallel to the shield case surface and the circuit board surface. Shield case structure characterized by forming a protruding flat surface. 2. The shield case structure according to claim 1, wherein parallelism with the circuit board is ensured by providing a freely deformable portion in the peripheral portion of the protrusion flat surface portion of the separate piece. 3. The shield case structure according to claim 1, wherein an L-shaped projection provided on a part of the separate piece is fitted and attached to a hole provided in the shield case. 4. The shield case structure according to claim 1, wherein the projection plane portion is formed by drawing a part of the shield case.