SE466626B - Device for encasing electronic components consisting of a lower and an upper casing part, which enclose a printed circuit board and are filled with electrical cladding material which encases the printed circuit board - Google Patents

Abstract

Device for encasing electronic components consisting of a plate casing 1, 2 filled with cladding material 5 and with the extension piece 14 also filled with the same material 5 and with the cladding material 5 being compressed in elastic deformation in the extension piece 14. A seal in the extension piece 14 is thereby ensured. <IMAGE>

Description

466 626 Description The present invention seeks to solve the above problems.

The invention is based on a glued hermetic capsule where elastic adhesive joints are constantly locked under mechanical compression, the elastic adhesive joint also functions as a bushing for an extension on a thin flexible printed circuit board, which thus functions partly as an electronics carrier inside the capsule and partly as a cable function. Inside the capsule, the circuit is enclosed by an elastic inert and heat-resistant enclosure material, this is the same material as the adhesive.

Manufacturing technology for the thin flexible printed circuit board is known in the art as so-called flex card, TAB technology or according to Swedish patent 85005425-2 Exemplary embodiment see figure 1.

Figure 1 shows a cross section of a finished capsule. The lower capsule half (1) is made of pressed sheet metal, for example 0.3-0.4 mm thick. At the bottom of this capsule half (1), a circuit consisting of a flexible printed circuit board (3) and mounted components (11) is glued with the glue (4). The lower half of the canister (1) is filled with a flexible enclosure mass (5), which can consist of silicone rubber or gel or high-purity flexible epoxy plastic, etc.

An upper canister half (2) is arranged on top of the lower one (1) in such a way that the joint (14) at the highest point in the bend is filled with casing mass (5).

The upper half of the capsule (2) is designed with a ridge that encloses an air cushion (6). At the highest point of the upper capsule half (2) there is a hole (7) which is soldered again with solder (8). An extension of the flexible pattern plate (3) extends between the lower capsule half (1) and the upper capsule half (2) and continues outside the capsule as a flat cable (10).

The portion of the printed circuit board (3, 11) that passes between the capsule halves and on the outside must be insulated with suitable rubber insulation.

The capsule halves (1, 2) are fixed to each other by a depression (9).

Before pressing in (9), the circuit (3, 11) must be mounted in the lower half of the canister (1) and the liquid canister mass (5) must be filled to the width. Then the upper half of the canister (2) is laid on, the deflection (12) sinking into the canister mass (5) so much that the canister mass (5) floats out and fills a part of the joint (14).

Stop (13) must be provided on the lower canister half (1) so that the upper canister half (2) does not sink further down than a millimeter-thick layer of canister mass (5) remains in the joint (14).

When applying the upper capsule half, the evacuation hole (7) must be open.

Thereafter, the encapsulating mass (5) is cured, which then changes to a solid rubber-like shape. After this step, a mechanical pressure is applied to the upper capsule half (2) at the joint (14) so that its rubber-like casing mass (5) is compressed at this point at the same time as a fixation in the form of a recess (9) is made. The cured rubber-like casing mass (5) present in the joint (14) will then be in a state of elastic deformation and tends to fill the joint (14) even if minor deformations occur between the capsule halves (1, 2) and the casing mass (5). ) takes place e.g. due to temperature differences and differences in the coefficient of temperature expansion. The joint (14) then does not become as dependent on the adhesion of the enclosure mass (5). Finally, the hole (7) was soldered again.

The enclosed air cushion (6) serves to equalize the pressure at the different volumes that the enclosure mass (5) assumes at different temperatures. \ _,.-_

Claims (1)

3,466,626 Claims. Device for encapsulating electronics consisting of a lower capsule half (1) and an upper capsule half (2), both of sheet metal. These enclose an at least partially flexible pattern plate (3) and are filled with an elastic housing mass (5) which encloses the pattern plate (3) and fills the joint (shelter) between the lower capsule half (1) and the upper housing half (Z). Characterized by the fact that the casing mass in the joint is compressed during elastic deformation and that this deformation is locked in that the capsule halves (1,2) have one or more indentations (9) which prevent the upper capsule half (2) from being able to separate from the lower one. capsule half (l).