HK1104116A - Insert molding electronic devices - Google Patents

Description

Insert molded electronic device

Background

The following description relates to packaging electronic devices.

Computer memory and other peripheral devices may be embedded in the computer or may be external devices selectively connectable to the computer through an external interface. Some peripheral devices are now small enough to be embedded in small, thin, card-like packaging components that can be plugged into specially designed sockets typically found in portable personal computers or digital cameras. Due to the many possible methods of making interfaces between computers and such devices, respective standards have been established by the personal computer memory card international association ("PCMCIA"), the japan electronic data interchange council ("JEDIC"), the international organization for standardization ("ISO"), the compact flash association ("CFA"), and so forth. These standards specify the shape and size of the device housing and the design of the connector/computer interface. Such peripheral devices, which may or may not conform to industry standards, are commonly referred to as PC cards.

One method for providing a plastic housing for a PC card is to manufacture two injection molded shells, place the electronic device between the two shells, and then mate the two shells together by sonic welding or using an adhesive. Another approach is to simultaneously injection mold the top and bottom of the PC card housing to enclose the electronic device. To hold the electronic device in place during the encapsulation process, locating pins are placed in the electronic device during the injection molding process to suspend the electronic device in place in the mold. The resulting PC card has holes in both the housing and the electronic device (which are not part of the final PC card) caused by the alignment pins.

Disclosure of Invention

This specification describes methods and apparatus for packaging electronic devices. In general, in one aspect, the invention includes positioning an electronic device on a base and over-molding (over-mold) a cover over at least a portion of the base and a portion of the electronic device. The cover and the base together form an enclosure for the electronic device.

Implementations of the method may include one or more of the following features. The electronic device may be a thin walled semiconductor, printed circuit board, or flash memory module. The electronic device may be adhered to the base prior to over-molding the lid. The base may include a recess for placement of the electronic device. The base may include one or more raised features and the electronic device may include one or more corresponding recesses. The electronic device may be positioned on the base by engaging one or more raised features with one or more recesses. The cover and/or base may include an opening that provides access to an interface on the electronic device. The base may be plastic and the lid may be of a thermoplastic material such as Acrylonitrile Butadiene Styrene (ABS) or other suitable material.

In general, in another aspect, the invention includes positioning an electronic device on a base, positioning a faceplate on at least one of the base and the electronic device, the faceplate having a surface area less than a surface area of the base, over-molding a cover into the base and at least a portion of the electronic device, wherein an upper surface of the faceplate is substantially exposed.

Implementations may include one or more of the following features. The panels may be plastic and may be formed by injection molding and/or die cutting. The panel may be adhered to the base and/or the electronic device.

The invention may achieve some, all, or none of the following advantages. A solid housing for an electronic device is formed that can be stronger, more durable, and hold the electronic device more firmly in place than a housing formed by mating two shells with a gap between the shells. The creation of an outer shell reduces the risk of damaging or misaligning the electronic device, which may occur when mating two shells encapsulating the electronic device by sonic welding. A solid housing may be provided for an electronic device without the need to form alignment pins and corresponding holes in the electronic device, as is required when encapsulating the electronic device in a single injection molding process. By limiting the pressure on the device during molding in one direction, the risk of damage to the electronic device during injection molding is further reduced. Furthermore, the over-molding into the pre-fabricated shell may omit at least one manufacturing step, i.e., mating the two shells by sonic welding or application of an adhesive. The panel may be embedded in the housing, for example, to provide an area for marking the contents of the electronic device in a contrasting color, thereby avoiding subjecting the packaged electronic device to subsequent printing processes that could potentially damage the electronic device (such as pad printing the marked area into the housing).

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features and advantages of the invention will become apparent from the following description, the accompanying drawings, and the claims.

Drawings

These and other aspects will now be described in detail with reference to the following drawings.

FIG. 1A shows a PC card.

FIG. 1B is a cross-sectional view along line A-A of the PC card shown in FIG. 1A.

Fig. 2 is an exploded view of the electronics and housing base.

Fig. 3 is a flow chart showing a process of insert molding an electronic device.

Fig. 4A is an exploded view of an injection molding apparatus.

Fig. 4B is a perspective view of a portion of the injection molding apparatus of fig. 4A.

Fig. 5 shows the housing base.

Fig. 6 shows the housing base.

FIG. 7A shows a PC card including an embedded panel.

FIG. 7B is a cross-sectional view along line B-B of the PC card of FIG. 7A.

Fig. 8 is an exploded view of the electronics, inset panel, and housing base.

Like reference symbols in the various drawings indicate like elements.

Detailed Description

FIG. 1A shows a PC card 100 formed from a base 5, a cover 60, and an electronic device 40 partially enclosed by the base 5 and the cover 60. The base 5 is manufactured by injection molding or die cutting. The electronic device 40 is positioned on a base that acts as a positioning device during the overmolding process, and then a lid 60 is overmolded over the base 5 and at least a portion of the electronic device 40, thereby creating a strong and durable enclosure for the electronic device 40. The over-molded cover 60 over the base 5 leaves an opening 70 that exposes a portion of the electronic device 40, including the interface 50. FIG. 1B shows a cross-sectional view of PC card 100 shown in FIG. 1A taken along line A-A. The lid 60 and base 5 may be formed from suitable materials including, for example: thermoplastic materials such as Acrylonitrile Butadiene Styrene (ABS), polycarbonate, ABS polycarbonate, styrene, polystyrene, acrylic, nylon or polyester. The above list of materials is not intended to be exhaustive and other suitable materials may be used to form the lid 60 and base 5, with different materials being used for the lid 60 and base 5, respectively.

Fig. 2 shows an embodiment of the base 5 comprising a planar portion 10 and a side 20. An example of an injection molded base housing is disclosed in U.S. patent No. 5,833,785 entitled "encapsulating a Small-format electrical Device" to Centofante at 11/10 of 1998, which is hereby incorporated by reference in its entirety. Images, text, etc. may be applied to the outer surface of the planar portion 10 of the base 5, such as by pad printing or ink jet printing, prior to over-molding the cover 60 into the base 5. The applied image may be checked for print quality to see compliance with commercial specifications. If the printing does not match, the base 5 can be discarded without causing the electronic device 40 to be lost or damaging the electronic device 40, as may occur when printing an image on the housing after the electronic device is packaged.

The electronic device 40 may be, for example, a thin walled semiconductor device such as a Printed Circuit Board (PCB) as shown. The electronic device 40 has an interface 50, which interface 50 may for example comprise conductor contacts, such as gold traces, for connecting with another electronic device. Interface 50 may be configured and attached to electronic device 40 using conventional techniques, and may optionally be configured according to standards established by CFA, PCMICIA, JEDIC, ISO, or other organizations. When assembled, the housing forms a thin rectilinear solid, with the cover 60 and base 5 defining the planar surface and thin side walls of the housing and providing access to the interface 50 for the rigid housing of the electronic device 40. In one embodiment, the PC card may include a PCB configured to form a flash memory module for insertion into an electronic device such as a digital camera or mobile phone. For example, this technique can be used to form a memory module, such as a miniSD memory module manufactured by SanDisk, with final dimensions of approximately 21.5cm by 20.0cm by 1.4 mm.

Fig. 3 shows a process 300 for at least partially enclosing electronic device 40 in an enclosure formed by base 5 and cover 60. The electronic device 40 is manufactured according to industry standards or otherwise (step 305). The base 5 is manufactured, for example, using the techniques described above (step 310). The order of steps 305 and 310 is not critical and either the electronic device 40 or the base 5 may be manufactured first.

The electronic device 40 is positioned on the base 5 (step 315). Referring to fig. 2, in one embodiment, the electronic device 40 may be disposed within a recess 30, the recess 30 providing a friction force suitable for holding the electronic device 40 in place during the over-molding of the cover 60. Positioning the electronic device 40 in the recess 30 may also provide a thinner PC card 100. Referring to fig. 6, in another embodiment, the raised feature 610 is disposed on the base 600 (e.g., on the base 600 or within a recess 620 in the base 600). The raised features 610 protrude sufficiently from the surface of the base 600 or recess 620 to engage a corresponding recess or recess formed in the electronic device 40 to hold the electronic device 40 in place during over-molding of the lid 60. Two raised elements 610 are shown in fig. 6, however, any number of raised elements may be used. The shape of the raised feature 610 is not critical and may be conical, hemispherical, cubic, cylindrical, rectilinear, pyramidal, or some other configuration. Alternatively, the electronic device 40 may be positioned at a desired location on the base 5 and held in place by the use of adhesives, vacuum systems, or other convenient means.

Referring again to fig. 3, the base 5, upon which the electronic device 40 is placed, is placed within an injection mold cavity that will be used to over mold the lid 60 (step 320). This step may be omitted if the base 5 is formed in an injection mold, the electronic device 40 being positioned on the base 5 without removing the base 5 from the mold, the same mold being used to form the cover 60. The lid 60 is over-molded onto the base 5 and the electronic device 40 (step 325). A shut-off mechanism may be used to prevent over-overmolding of at least a portion of the electronic device 40, particularly the interface 50. The shut-off mechanism may be a raised portion of the inner surface of the injection mold cavity that faces a portion of the electronic device when the mold is closed, thereby preventing any molding material from covering the area of the electronic device covered by the shut-off mechanism. The base 5 acts as a locating means for the electronic device 40 during the overmolding process, thereby eliminating the need for locating pins and corresponding holes in the electronic device 40 and preventing movement of the electronic device. After the injection is complete, the molding material may be hardened and the injection mold 400 opened and the resulting PC card 100 may be removed (step 330).

A description of An exemplary method and apparatus For injection molding is provided in U.S. Pat. No. 5,833,903 entitled "injection molding Encapsulation For An Electronic Device direct to injection molding", issued to Centofante at 10.11.1998, which is hereby incorporated by reference in its entirety.

In one embodiment, the exemplary injection molding apparatus shown in fig. 4A and 4B may be used to over mold the lid 60. For illustrative purposes, the techniques described are for creating a PC card 100 as shown in FIG. 1, although the techniques described below with reference to FIGS. 4A and 4B may be used to form differently configured PC cards, such as PC cards having a base as shown in FIGS. 5 or 6 (described below). Referring to fig. 4A, the injection mold 400 includes a top plate 410 and a base plate 420. The top plate includes an inlet 415 that provides a path for injecting molding material, such as thermoplastic material, into the injection mold 400. Fig. 4B shows the inner surface 412 of the top plate 410, including a distribution runner (distribution runner)425 and a grate 422. The gate 422 may communicate with the inlet 415 through a distribution rotor 425. In another embodiment, the gate 422 may communicate directly with the inlet 415. The gate 422 allows thermoplastic material to enter into a top mold cavity 424, which mold cavity 424 forms the shape of the overmolded cap 60. The top mold cavity 424 includes a shut off mechanism 423 that prevents the thermoplastic material from covering a portion of the electronic device 40. The shut off mechanism 423 may be a raised area where the top mold cavity 424 contacts a portion of the electronic device 40 when the mold is closed, thereby preventing a cavity from being formed in this area that would receive the molding material.

The top plate 410 includes pins 428 configured to engage corresponding apertures 435 formed in the base plate 420 to connect the top plate and the base plate. The base plate 420 includes a recess 430 for placing the pre-formed base 5 in the mold 400 during over-molding of the lid 60. The electronic device 40 is positioned on the base 5 during the overmolding process, optionally attached to the base 5. After the base 5 and the electronic device 40 are positioned within the recess 430 of the base plate 420, the top plate 410 is secured to the base plate 420 using the pins 428 that engage the corresponding apertures 435. Thermoplastic material is injected into the mold cavity 424 through the inlet 415 to cover a portion of the electronic device 40 and the planar surface 10 of the base 5 to form the lid 60. The thickness of the cover 60 varies with the surface topology of the base 5. For example, the base 5 may include sidewalls and surface features of different heights. In one embodiment, the cover 60 may be overmolded such that the overmolding increases the height of the finished PC card from the base 5 by approximately 0.2mm above the existing side walls of the base 5.

The over-molded material may be a thermoplastic material, such as ABS, and may or may not be the same color as the base 5. During the injection molding process, the thermoplastic material bonds to the base 5 and at least some portions of the electronic device 40. The heat and pressure generated by the injection molding process melts the surface of the base 5 that is in contact with the molding material, resulting in a chemical bond between the base 5 and the cover 60. In addition, as the lid 60 cools, the plastic shrinks during cooling, forming a mechanical bond between the base 5 and the lid 60. Over-molding with a thermoplastic material in a plastic family similar to that used to form the base 5 can improve the bond between the lid 60 and the base 5.

In one embodiment, by injecting the first plastic layer at a low pressure to form a protective shell over the electronic device 40, the risk of damage to the electronic device 40 due to over-molding at high pressure may be reduced. The plastic may be a chemically activated heat curable material that hardens rapidly. A second layer of plastic is then injected at high pressure to complete the formation of the over-molded lid. The first and second layers may be formed in the same molding process (i.e., without removing the base 5 and electronic device 40 from the mold cavity), or may be performed as a two-step molding process.

Fig. 2 shows an embodiment of the base 5 comprising an area of reduced thickness with respect to the planar portion 10, which constitutes a recess 30 for accommodating an electronic device 40. In another embodiment shown in fig. 5, the base 500 includes a side 530, the side 530 extending along the entire perimeter of the base 500 except for the opening 527. A recess 520 for receiving an electronic device may be formed in the base 500 such that an edge of the recess coincides with an opening 527 in a side 530 of the base 500. The electronic device 40 may be positioned within the recess 520 so that an interface on the electronic device is accessible through the opening 527 for connection with another electronic device. The recess 520 limits lateral movement of the electronic device within the base 500, thereby holding the electronic device 40 in place during the overmolding process. By providing the boundary of the opening 527 and forming a portion of the side 525 of the fourth side of the recess 520, the electronic device 40 may be prevented from moving toward the opening 527.

Fig. 6 shows another embodiment of a base 600. The base 600 includes a planar portion 605 that includes a recessed region 620 and a notch 640 adjacent to an edge of the recessed region 620. The electronic device may be positioned within the recess 620, which limits lateral movement of the electronic device within the base 600 during over-molding of the lid. As previously described, the electronic device may be further held in place by using the raised features 610 to engage corresponding recesses in the electronic device. The electronic device may be positioned with the interface facing the base 600 so that the interface may be accessed through the cutout 640 so that an electrical connection can be established with another electrical device. Alternatively, if the electronic device has an interface on both sides and/or an interface at the end of the electronic device, the interface may be accessed from the base side through the cutout 640 or from the cover side by forming the cover so as to keep the interface exposed as described above.

FIG. 7A shows another embodiment of a PC card 700 that includes an inset panel 710. PC card 700 is made up of a base 720, a lid 730, an inset panel 710, and an electronic device 740 partially enclosed by base 720 and lid 730. The cover 730 includes an opening for exposing the interface 750 of the electronic device 740, and an opening for embedding the panel 710. FIG. 7B shows a cross-sectional view of PC card 700 taken along line B-B.

The inset panel 710 can provide an area of contrasting color to the rest of the housing (or at least contrasting color to the lid 730) suitable for labeling or printing. For example, the PC card 700 may include a black thermoplastic base 720 and lid 730, a white inset panel 710, and then the white inset panel 710 may be printed or handwritten in a contrasting color. Traditionally, creating labels with contrasting color backgrounds (e.g., black labels on a white background) requires printing a white field directly onto the cover and printing text on the white field. Printing the white fields on the black cover requires several passes, requiring more time and expense. After several passes, the white field may not be completely opaque or may not meet commercial specifications. In addition, multiple printing processes may damage the delicate electronic devices packaged within the PC card.

Referring now to fig. 8, an exploded view of the base 720 with attached inset panel 710 and the electronic device 740 is shown. The base 720 is configured to receive an electronic device, as described above with reference to fig. 2, 5, and 6. For illustrative purposes, the base 720 is shown similar to the base 5 of FIG. 2. The inset panel 710, which has a surface area 830 that is smaller than the top surface of the electronic device 740, can be bonded to the electronic device 740 using, for example, an adhesive. Alternatively, the embedded plastic panels 710 may be positioned such that some or all of the embedded panels 710 are in contact with the upper surface of the base 720.

In one embodiment, the inset panel 710 is positioned within a recess formed in the base 720. The recess may be designed such that the inset panel 710 may be placed within the recess that forms a friction fit between the inset panel 710 and the base 720. The friction fit prevents the inset panel 710 from moving laterally when positioned on the base 720 and holds the inset panel 710 stationary during the over-molding process. The inset panel can be preformed using conventional techniques, for example, by injection molding or die cutting, or can be made of any suitable material, for example, a thermoplastic material such as Acrylonitrile Butadiene Styrene (ABS), polycarbonate, ABS-polycarbonate, styrene, polystyrene, acrylic, nylon, or polyester. The above list of materials is not meant to be exhaustive and other suitable materials may be used. In one embodiment, inset panel 710 is approximately 8mm by 12mm by 0.1-0.3mm in size for use with a PC card approximately 21.5cm by 20.0cm by 1.4mm in size.

During the over-molding process, a cut-off mechanism is used to prevent molding to the top surface (or at least a portion) of the inset panel 710. In one embodiment, the lid 730 may be coplanar with the inset panel 710. The overmold material can be any suitable material, including, for example: thermoplastic materials such as Acrylonitrile Butadiene Styrene (ABS), polycarbonate, ABS polycarbonate, styrene, polystyrene, acrylic, nylon or polyester. The above list of materials is not meant to be exhaustive and other suitable materials may be used. Over-molding with a molding material in a plastic family similar to the material used in the base 720 and inset panel 710 provides improved adhesion between the lid 730 and the base 720 and inset panel 710. During the injection molding process, the molding material adheres to the base 720, portions of the electronic device 740, and the sides (or at least portions thereof) of the embedded panel 710.

In another embodiment, inset panel 710 is added to PC card 700 after over-molding lid 730. The base 720 including the electronic device 740 is placed within the injection mold 400 for over-molding. A shut-off mechanism is used to prevent the molding material from accumulating on at least a portion of the electronic device 740, forming a recess in the lid configured to receive the inset panel 710. The inset panel 710 is inserted into the recess and attached to the base 720 or the bottom of the electronic device 740, for example, using an adhesive or a friction fit.

In another embodiment, the cover or base may be manufactured such that the cover or base may include an inset panel. For example, the inset panel may be pre-molded or die cut. The inset panel can then be placed within an injection mold, or a lid or base can be molded to surround the inset panel. The electronic device may be positioned on the lid or base and the corresponding base or lid over-molded as described above. Alternatively, the resulting lid or base, including the embedded panels, may be mated into a pre-molded corresponding base or lid using conventional techniques such as sonic welding.

Some of the steps described herein may be performed using a robot or computer controlled device, such as positioning the electronic device on a base, transferring the base to an injection mold for molding and/or removing a PC card from the injection mold.

Although only a few embodiments have been described in detail above, other modifications are possible. For example, more than one electronic device may be at least partially enclosed in a single housing using the described techniques. The housing may be configured in shapes other than a rectilinear solid. The techniques described herein are not limited to forming "PC cards" and may be used to package any electronic device. The steps of the methods described herein may be performed in a different order and still achieve desirable results. Other embodiments are within the scope of the following claims.

Claims (38)

1. A method of packaging an electronic device, comprising:

positioning an electronic device on a base; and

the cover is over-molded to at least a portion of the base and a portion of the electronic device, the cover and the base comprising an enclosure for the electronic device.

2. The method of claim 1, wherein the electronic device is a thin walled semiconductor device.

3. The method of claim 1, wherein the electronic device is a printed circuit board.

4. The method of claim 3, wherein the printed circuit board is a flash memory module.

5. The method of claim 1, further comprising:

the electronic device is adhered to the base prior to over-molding the lid.

6. The method of claim 1, wherein positioning the electronic device on the submount comprises positioning the electronic device in a recess formed in the submount.

7. The method of claim 1, wherein the base includes one or more raised features and the electronic device includes one or more corresponding recesses, and wherein positioning the electronic device on the base includes engaging the one or more raised features within the one or more recesses.

8. The method of claim 1, wherein the step of over-molding the cover includes forming an opening in the cover to provide access to an interface on the electronic device.

9. The method of claim 1, wherein the base includes an opening to provide access to an interface on the electronic device.

10. The method of claim 9, wherein the step of over-molding the lid comprises including an opening to provide a second access to an interface on the electronic device.

11. The method of claim 1, wherein the base is formed of a plastic material.

12. The method of claim 1, wherein the cover is formed from a thermoplastic material.

13. The method of claim 12, wherein the thermoplastic material is Acrylonitrile Butadiene Styrene (ABS).

14. An apparatus, comprising:

a base;

an electronic device positioned on the base; and

a cover overmolded onto the base and at least a portion of the electronic device, the cover and the base enclosing the electronic device.

15. The apparatus of claim 14, wherein the electronic device is a thin walled semiconductor device.

16. The apparatus of claim 14, wherein the electronic device is a printed circuit board.

17. The device of claim 16, wherein the printed circuit board is a flash memory module.

18. The apparatus of claim 14, wherein the electronic device is adhered to the base prior to over-molding the lid.

19. The apparatus of claim 14, wherein the base includes a recessed portion configured to receive the electronic device.

20. The apparatus of claim 14, wherein the base includes one or more raised features and the electronic device includes one or more corresponding recesses, and wherein the one or more raised features are configured to engage the one or more recesses.

21. The apparatus of claim 14, wherein:

the cover includes an opening;

the electronic device includes an interface; and

the interface is accessible through an opening in the cover.

22. The apparatus of claim 14, wherein:

the base comprises an opening;

the electronic device includes an interface; and

the interface is accessible through an opening in the base.

23. The apparatus of claim 14, wherein:

the cover includes an opening;

the base comprises an opening;

the electronic device includes one or more interfaces; and

the one or more interfaces may be accessible through an opening in the base and an opening in the lid.

24. The apparatus of claim 14, wherein the base is formed of a plastic material.

25. The apparatus of claim 14, wherein the cover is formed from a thermoplastic material.

26. The apparatus of claim 25, wherein the thermoplastic material is Acrylonitrile Butadiene Styrene (ABS).

27. A method of packaging an electronic device, comprising:

positioning an electronic device on a base;

positioning a faceplate on at least one of the base and the electronic device, the faceplate having a surface area less than a surface area of the base; and

the cover is overmolded onto the base and at least a portion of the electronic device, wherein an upper surface of the panel is substantially exposed.

28. The method of claim 27, wherein the panel is formed by injection molding.

29. The method of claim 27, wherein the panel is formed of a plastic material.

30. The method of claim 27, wherein the panel is formed by die cutting.

31. The method of claim 27, further comprising adhering the panel to the base.

32. The method of claim 27, further comprising adhering the panel to an electronic device.

33. An apparatus, comprising:

a base;

an electronic device positioned on the base;

a faceplate positioned on at least one of the base and the electronic device, the faceplate having a surface area less than a surface area of the base; and

a cover overmolded onto the base and at least a portion of the electronic device, wherein an upper surface of the panel is substantially exposed.

34. The apparatus of claim 33, wherein the panel is formed by injection molding.

35. The apparatus of claim 33, wherein the panel is formed of a plastic material.

36. The apparatus of claim 33, wherein the panel is formed by die cutting.

37. The apparatus of claim 33, wherein the panel is adhered to the base.

38. The apparatus of claim 33, wherein the panel is adhered to the electronic device.