JPS5855586B2 - bubble memory device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bubble memory device with a reduced external size.

Bubble memory devices usually include a magnetic garnet layer formed on a non-magnetic garnet surface by an LPE method, etc.
This layer consists of a conductor pattern layer for controlling current for bubble generation, copying, etc., a soft ferromagnetic material pattern layer for bubble transfer paths, etc., and a silica layer for insulating and protecting the above layers. Between a bubble memory chip, a device substrate made of alumina or glass epoxy, etc. to which this chip is attached, and lead pins provided on this substrate and protruding outward from the device and connected to the chip and an external peripheral circuit. a pair of orthogonal drive coils that provide a horizontal rotating magnetic field to the chip for bubble transfer, and a permanent drive coil that provides a perpendicular bias magnetic field to the chip to ensure the stable existence of the bubbles. It is made up of magnets, etc.

FIG. 1 is a diagram showing a state in which lead pins are attached to a substrate of an example of a conventional bubble memory device.

Reference numeral 1 denotes a device substrate (hereinafter simply referred to as the substrate) made of glass epoxy or the like, and a bubble memory chip 2 is attached to a recess provided approximately in the center of this substrate.

There are two notches in the substrate 1 that engage with one side 5b of the rotating magnetic field generation drive coil, and outside these notches there is a terminal arrangement part 1a tlb, where the lead pin 4 is inserted.
．． 4a and 4b are fixed.

In order to propagate signals between an external circuit (not shown) and the bubble memory chip 2, the substrate 1 extends from the base of each lead pin 4 to the vicinity of the bonding pad of the bubble memory chip 2.
A signal line 3 is formed on the surface by a printing wiring method or the like.

The memory chip 2 is fixed in the recess of the substrate 1, and the bonding pads and the ends of the respective predetermined signal lines 3 are connected by wire bonding or the like to complete the installation.

After attaching the memory chip 2 to the substrate 1, as shown in FIG. 2, a drive coil 5a is fitted in the X direction, and a drive coil 5b is fitted in the Y direction, and the terminals of both coils are connected to the lead pins 4a and 4b, respectively. Connect to.

Furthermore, a pair of plate-shaped permanent magnet plates (not shown) and a magnetic shunt plate for applying a bias magnetic field in the perpendicular direction to the bubble memory chip 2 are arranged and housed in the shield yoke 6 as shown in FIG. Then, resin 7 is filled on both side peripheral surfaces where the lead pins are arranged to complete the bubble memory device.

The conventional bubble memory device as described above has a large number of lead pins arranged on one side, such as the signal lead pin 4 to the memory chip 2 and the lead pins 4a and 4b to the drive coil. Although only a relatively small number of lead pins to the memory chip 2 are arranged, the substrate 1 is made into an asymmetrical shape in accordance with the long dimension L1 required for arranging the large number of lead pins, and therefore, the shape of the memory device is reduced. There was a problem in that the dimension in the lead pin arrangement direction had to be made unnecessarily long.

In order to avoid such problems, it has been conventionally practiced to use a symmetrical substrate in which half of all the lead pins required for the bubble memory device can be arranged symmetrically on both needle sides.

However, in this case, as can be easily seen from Fig. 2, the inner width of one of the pair of drive coils 5a needs to be longer than the length of the side of the board in the direction in which the lead pins are arranged. The inner width of the coil 5a becomes larger.

The inductance of the coil increases as the width of the coil increases (
(If the number of turns and inner thickness are constant), it will increase proportionally,
Another problem arises in that the load on the drive coil power source is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bubble memory device that solves the problems of the conventional bubble memory device.

In order to achieve the above object, in the present invention, in order to fit one side of the drive coil into the bubble memory chip mounting part near the center, a short terminal arrangement part in which a small number of terminals are arranged with the same width as the chip mounting part is placed on the one stitch side. Although the number is smaller than in the conventional case, an asymmetric substrate is used which has a long terminal arrangement section on the outside where a large number of terminals are arranged, and the terminals from the bubble memory chip and the drive coil terminals are appropriately distributed, so that both devices can be integrated. It was designed to connect to lead pins arranged symmetrically, half on the outside.

By doing so, the inductance of the drive coil does not increase, and there is also no problem that more lead pins are arranged on the outer side than on the other side, making the dimension of the device in the lead pin arrangement direction unnecessarily long.

Although some of the terminals of the drive coil cannot be attached to the substrate, there is no difficulty in manufacturing this point, for example, if all the lead pins are treated as an integrated lead frame up to the middle of the manufacturing process, as will be described later.

An embodiment of the present invention will be explained in detail below with reference to FIGS. 4 to 7.

FIG. 4 shows a board 1' according to this embodiment, in which the longer terminal array portion 1a' has 1. Since only one terminal of the drive coil is arranged, the length L2 of this part is 1.2.
It is shorter than the length Ll of the terminal array portion 1a of the conventional board 1 shown in the figure by the length of three drive coil terminals.

Specifically, when the pitch of the lead pins is 2.54 mm, L1 was 22.86 mtrt in the conventional case, but L2 is shortened to 15.24 mm according to the embodiment of the present invention.

On the other hand, compared to the case of using a symmetrical board equipped with a terminal arrangement section in which seven terminals are arranged on each side, the inner width of the drive coil 5a to be inserted is narrower by 7.62 mm, and the inductance of the corner coil is also reduced. .

FIG. 5 shows a lead frame 8 for this embodiment in which 14 lead pins are symmetrically arranged and integrated into 7 lead pins.

After assembling the pair of drive coils 5a and 5b on the board 1a', as shown in FIG. Although not shown, as in the case of the board 1 shown in FIG. Furthermore, the terminal of the drive coil 5a is connected to the base of the lead pin 4a', and the terminal of the coil 5b is connected to the base of the lead pin 4b.
Connect to the base of /.

A connecting frame (hereinafter referred to as a dam) between each lead pin of the lead frame 8 has a function of preventing resin from flowing out between the lead pins during a resin filling and molding operation (hereinafter referred to as a mold) of a device.

After molding, the dam is cut off using a press or the like to complete the external shape as shown in FIG.

It goes without saying that the present invention can be easily practiced without using a lead frame with integrated lead pins by using an appropriate jig.

As described above, according to the present invention, the bubble memory device can be made smaller without increasing the inductance of the drive coil.

[Brief explanation of the drawing]

FIGS. 1 to 3 show an example of a conventional bubble memory device, and show the state in which lead pins are attached to a substrate, the state in which a drive coil is further combined, and the completed state, respectively. 4 to 1 show an embodiment of the present invention, and are diagrams of the board, lead frame for this embodiment, 1 drive coil insertion and lead frame mounting state, and completed outline, respectively. 1.1'...Substrate, 1 a + 1 a'+
1 b, 1 b'・-,. Terminal arrangement section, 4 J 4a l 4a'l 4b l
4b'--Lead pin, 5a, 5b...
Drive coil, 8...Lead frame.

Claims (1)

[Claims] 1. In order to fit one of the pair of orthogonal drive coils into the bubble memory chip mounting section near the center, a short terminal arrangement section in which a small number of terminals are arranged with the same width as the chip mounting section is placed on the one-stitch side. To,
Using an asymmetric device board that has a long terminal arrangement section on the fine needle side that arranges multiple terminals, the terminals from the bubble memory chip and drive coil terminals are connected to lead pins arranged symmetrically, half on each side of the device. A bubble memory device characterized by: 2. During the manufacturing process, the symmetrically arranged lead pins are worked as an integrated lead frame, and after each lead pin base is fixed to the bubble memory device exterior,
2. The bubble memory device according to claim 1, wherein the connecting frame between each lead pin is cut and removed.