Orientation-independent device configuration and assembly

The present disclosure is directed to orientation-independent device configuration and assembly. An electronic device may comprise conductive pads arranged concentrically on a surface of the device. The conductive pads on the device may mate with conductive pads in a device location in circuitry. Example conductive pads may include at least a first circular conductive pad and a second ring-shaped conductive pad arranged to concentrically surround the first conductive pad. The concentric arrangement of the conductive pads allows for orientation-independent placement of the device in the circuitry. In particular, the conductive pads of the device will mate correctly with the conductive pads of the circuitry regardless of variability in device orientation. In one embodiment, the device may also be configured for use with fluidic self-assembly (FSA). For example, a device housing may be manufactured with pockets that cause the device to attain neutral buoyancy during manufacture.

TECHNICAL FIELD

The present invention relates to electronic devices, and more specifically, to devices that may be populated into circuitry without concern as to a particular orientation for the device.

BACKGROUND

In a typical electronics manufacturing process, circuitry including, but not limited to, printed circuit boards, flexible substrates, packages such as multichip modules (MCM), etc. may be populated with electronic devices using pick-and-place operations. For example, the circuitry may be routed through machines equipped with vision systems for identifying device placement locations in the circuitry and manipulators configured to pick up devices from a supply location (e.g., rail, reel, etc.) and place the devices into the previously identified device locations. Pick-and-place manufacturing has been effective at least from the standpoint of accurately populating circuitry with a variety of devices at a speed substantially faster than manual device insertion.

However, applications are now emerging wherein circuitry may need to be populated with high volumes of the same device. For example, recent developments in light emitting diode (LED) technology have created substantial demand for LED-based light sources due to their high quality light, low power consumption and long life. Manufacturing large-scale lighting (e.g., for commercial or professional use) may involve populating circuitry with thousands of the same LED. While pick-and-place manufacturing can do the job, high machine time and upkeep costs, limited production speed, etc. for performing such simple/repetitive assembly can be prohibitive.

Electronic manufacturing methods better suited for high volume production are now in development. For example, fluidic self-assembly (FSA) is a manufacturing method that relies upon the wetting behavior of liquids (e.g., solder) to populate circuitry. For example, electronic components (e.g., LED dies) may be assembled by drawing a circuit substrate through an agitated liquid bath. The liquid bath may be heated above the melting point of solder that has been pre-printed on the circuit board. Due to the agitation, bond pads on the components may randomly contact the molten solder on the circuit substrate, at which point the solder provides enough wetting and lubrication for the components to naturally find their device locations (e.g., their minimum energy configuration). In particular, the wetting effect of the melted solder may cause conductive pads or bumps on the devices to be drawn to conductive pads in the device locations.

Regardless of the type of manufacturing used, device misorientation is a problem that continues to plague device manufacturers with delays due to rework, device malfunctions due to incorrectly attached components, etc. Existing electronic components are orientation-dependent in that their pin/pad layout requires the component to be populated into circuitry in a particular orientation for proper component operation. For correct orientation, pick-and-place manufacturing may rely upon the components being properly oriented in their carriers (e.g., tubes, reels, etc.). However, devices are often incorrectly oriented in their carriers due to, for example, packaging errors, movement during shipment, etc. FSA manufacturing is even more problematic in regard to device orientation in that during population in FSA there is little control for device orientation.

DETAILED DESCRIPTION

As referenced herein, “circuitry” may comprise any substrate onto which electronic devices may be inserted, placed, populated, etc. Examples of circuitry may include, but are not limited to, circuit boards, flexible substrates, packages such as multichip modules (MCM), etc. Device orientation, as referenced herein, may pertain to the orientation of a device with respect to a desired orientation dictated by a device location on a substrate into which the device is being populated (e.g., during the manufacture of circuitry). In some instances, conductive pads on the device may still mate with conductive pads in a device location even when the device orientation is twisted out of proper alignment. In traditional electronic devices, this situation may result in incorrect conductive pad coupling, and without correction, malfunction of the device/circuitry.

Embodiments consistent with the present disclosure may include an electronic device with conductive pads arranged concentrically on a surface of the device. The conductive pads on the device may mate with conductive pads in a device location in circuitry. Example conductive pads may include at least a first circular conductive pad and a second ring-shaped conductive pad arranged to concentrically surround the first conductive pad. The concentric arrangement of the conductive pads allows for orientation-independent placement of the device in the circuitry. In particular, the conductive pads of the device will mate correctly with the conductive pads of the circuitry regardless of variability in device orientation. In one embodiment, the device may also be configured for use with fluidic self-assembly (FSA). For example, a device housing may be manufactured with pockets that cause the device to attain neutral buoyancy during manufacture.

In one embodiment, a device may comprise, for example, a device housing, at least one electronic component and conductive pads. The at least one electronic component may be enclosed within the device housing. The conductive pads may be structurally coupled to the device housing and electronically coupled to the at least one electronic component. Consistent with the present disclosure, the conductive pads may be arranged concentrically on the device.

The conductive pads may comprise, for example, at least a first conductive pad and a second conductive pad. The first conductive pad may be circular in shape, while the second conductive pad may be ring-shaped and arranged to concentrically surround the first conductive pad. The first conductive pad may be electronically isolated from the second conductive pad by at least one of an air gap or an insulator. In one example configuration, the first conductive pad may further have a surface area larger than a surface area of the second conductive pad.

In one embodiment, the first conductive pad may be electronically coupled to a first terminal on the at least one electronic component and the second conductive pad is electronically coupled to a second terminal on the at least one electronic component. For example, at least one of the first conductive pad may be electronically coupled to the first terminal by a wire bond or the second conductive pad may be electronically coupled to the second terminal by a wire bond. Alternatively, at least one of the first conductive pad may be electronically coupled to the first terminal by direct die attachment or the second conductive pad may be electronically coupled to the second terminal by direct die attachment. It is also possible for the first conductive pad to be electronically coupled to the first terminal by direct die attachment and the second conductive pad to be electronically coupled to the second terminal by a wire bond. In at least one example implementation, the at least one electronic component is a light emitting diode (LED), the first terminal is a cathode and the second terminal is an anode.

In one example implementation, the device may be for use in a fluidic self-assembly (FSA) manufacturing process. For example, the housing may comprise gas pockets formed in the housing to allow the device to attain neutral buoyancy during the FSA manufacturing process. The gas pockets may be formed by outgassing during manufacture of the housing. Embodiments consistent with the present disclosure may further comprise circuitry including a substrate having at least one device location into which a device is populated during manufacture of the circuitry. The at least one device location may include conductive pads structurally coupled to the substrate and electrically coupled to at least one circuit path in the substrate. The conductive pads may be arranged concentrically on the substrate. For example, the conductive pads may comprise at least a first conductive pad and a second conductive pad, the first conductive pad being circular in shape and the second conductive pad being ring-shaped and arranged to concentrically surround the first conductive pad. The first conductive pad may be electronically isolated from the second conductive pad by at least one of an air gap or an insulator. In one example configuration, the first conductive pad may also have a surface area larger than a surface area of the second conductive pad. The circuitry may further comprise a device populated into the at least one device location, the device including at least two conductive pads smaller in size than the first and second conductive pads and arranged to at least electrically couple to the first and second conductive pads. An example method consistent with the present disclosure may comprise populating circuitry with at least one device, the at least one device comprising conductive pads arranged concentrically on a surface of the at least one device to mate with conductive pads arranged concentrically at a device location in the circuitry and affixing the at least one device to the circuitry.

FIG. 1illustrates an example orientation-independent device configuration and assembly consistent with the present disclosure. Initially, it is important to recognize that the example illustrated inFIG. 1is merely for the sake of explanation herein, and is not intended to limit any embodiments of the present disclosure to a required implementation. Various embodiments of the present disclosure may employ alternative materials, layouts, manufacturing processes, etc. and still be considered within the scope of the systems, methods, teachings, etc. disclosed herein.

FIG. 1discloses circuitry100onto which devices102are being populated. Devices102are disclosed as light emitting diodes (LEDs), but may be any electronic device populated into circuitry100. InFIG. 1, circuitry100may be populated with devices102through an FSA manufacturing process. However, other manufacturing processes are also usable including, for example, a pick-and-place manufacturing process. In an example FSA manufacturing process, circuitry100(e.g., a substrate including at least one device location108) may be submerged in liquid104also containing loose devices106. Liquid104may then be agitated to help facilitate moving loose devices106to device locations108in circuitry100, and may be heated to melt solder previously applied to conductive pads110and112in device locations108. While only two conductive pads110and112are illustrated in the example ofFIG. 1, additional conductive pads may be included as necessary (e.g., based on the pin out of device102, etc.). For example, first conductive pad110may be circular in shape, and second conductive pad112may be ring-shaped and arranged to concentrically surround first conductive pad110. First conductive pad110may also be electronically isolated from second conductive pad112by insulators114(e.g., air gaps, ring-shaped insulating material, etc.). As circuitry100is withdrawn from liquid104, the conductive pads of loose devices106may adhere to the molten solder on conductive pads110and112(e.g. via wetting), and thus, loose devices106may become populated devices102.

However, as loose devices106float freely in agitated liquid104their orientation may change frequently. The conductive pad layouts in existing electronic devices may be sensitive to orientation change. In particular, there may be only one orientation allowing the conductive pads in a device to mate correctly to corresponding conductive pads110and112. The probability of incorrect device orientation in circuitry100, especially in FSA where there is little or no control over the orientation of device106prior to placement, becomes extremely problematic from the standpoint of the need for rework and/or the possibility for malfunction if incorrectly placed devices are not corrected.

Embodiments consistent with the present disclosure help to remedy this situation by providing an orientation-independent mounting system. Since conductive pads110and112are arranged concentrically on a surface of device102, twisting device102in either direction about the central concentric axis will not change how the conductive pads on device102make contact with conductive pads110and112in circuitry100. Eliminating the need to be aware of device orientation reduces the sensitivity involved when populating circuitry100, and may increase the overall speed of manufacturing processes, be it pick-and-place, FSA or even manual assembly.

FIG. 2illustrates example orientation-independent device housing configurations consistent with the present disclosure. As illustrated by the top view, device102may comprise, for example, an LED including a circular housing and lens similar to example devices102inFIG. 1. Further detail is provided in the bottom view of device102wherein a similar conductive pad arrangement including conductors200and202may be employed to mate with conductive pads110and112in device location108as disclosed inFIG. 1. During device placement, conductive pad200may be coupled to first conductive pad110in device location108while conductive pad202may be coupled to second conductive pad112in device location108.

Moreover, other configurations are possible consistent with the present disclosure. For example, device102′ presents another example LED with a rectangular housing and lens. Device102′ demonstrates that the shape of the housing may be variable without affecting the conductive pad arrangement. An alternative conductive pad arrangement is shown for device102′ wherein smaller conductive pads204and206are employed to mate with the previously presented conductive pad arrangement shown in silhouette on device102′ at208. Conductive pads204and206in device102′ may mate to conductive pads110and112, respectively, at device location108. The configuration may also be reversed with the smaller conductive pads being utilized at device location108and fully concentric conductive pads being employed on device102′. At least one advantage of the conductive pad arrangement illustrated for device102′ is that orientation-independence may still be possible with smaller conductive pads204and206. Utilizing smaller conductive pads204and206may, for example, make orientation-independent placement possible for devices with smaller housings, may yield more cost-effective devices, etc.

FIG. 3illustrates an example conductive pad arrangement consistent with the present disclosure. Device102″ may comprise a first conductive pad300having a significantly larger surface area than a second conductive pad302. First conductive pad300having a significantly larger area may help with component centering during circuit assembly. For example, during an FSA assembly process the larger first conductive pad300may facilitate device102″ to naturally find proper seating in device location108(e.g., via the wetting provided by the liquefied solder). In instances where device102″ is an LED, the enlarged surface area of first conductive pad300may also help to improve the operation of device102″ (e.g., thermal dissipation may increase in device102″ due to heat transferring through the large surface area provided by first conductive pad300).

FIG. 4illustrates in cross section example orientation-independent device electronics configurations consistent with the present disclosure. Exampled device102may comprise a housing400, lens402and electronic component404(e.g., an integrated circuit, chip, die, etc.). Conductive pads200and202(e.g., including202A and202B representing different sides of the same conductive pad202) may be structurally coupled to housing400and electronically coupled to conductive pads200and202. During population of circuitry100′, conductive pad200may be coupled to conductive pad110and conductive pads202(including202A and202B) may be coupled to conductive pad112(e.g., including112A and112B representing different sides of the same conductive pad112).

In the “one wire bond” example illustrated inFIG. 4, electronic component404may be electronically coupled to conductive pad200via direct die attach and to conductive pad202via wire bond406. Since conductive pads202A and202B are in actuality different sides of the same conductive pad202, a single wire bond may suffice for the coupling.

A “two wire bond” example inFIG. 4, discloses an additional wire bond408between electronic component404and conduction pad200(e.g., replacing the direct die attach to conduction pad200as shown in the one wire bond). A third “direct attach” example replaces the wire bonds with direct die attachments to pad202(202B and202A) as shown at410and412. The choice of whether to use direct die attach or wire bonding may depend on, for example, the type of electronic component404, device102, circuitry100′, etc.

FIG. 5illustrates an alternative example housing configuration consistent with the present disclosure. Device106′ may comprise a housing300′ in which gas pockets500are formed (e.g., during the manufacture of device106′). For example, volatile components may be added to the plastic prior to molding the device, causing housing300′ to outgas during device manufacture (e.g., during molding, reaction, curing, etc.). One example of material that may be employed in housing300′ is microcellular polyethylene terephthalate (MCPET). Gas pockets500may allow device106′ to attain neutral buoyancy in fluid104as shown at502(e.g., during an FSA manufacturing process). FSA schemes that involve sweeping of devices106′ onto a roll-to-roll flexible substrate may only require two-dimensional (2-D) agitation along the surface of the fluid104rather than three-dimensional (3-D) agitation in the liquid volume to induce self-assembly onto a substrate. This improvement may greatly reduce assembly time during FSA.

FIG. 6illustrates example operations associated with orientation-independent device configuration and assembly consistent with the present disclosure. In operation600, circuitry may be populated with at least one orientation independent device. Optional operations602and604may then be performed based on, for example, the need for error checking in the circuitry. For example, in a large panel LED light source it may be possible for some device locations to be left unpopulated without substantially affecting the operation of the light source. Thus, the occasional missing LED may not be noticeable to someone viewing the light source. However, in circuitry wherein having all devices being placed is essential, operations602and604may be necessary. In operation602a check for unpopulated device locations may be performed, and if any unpopulated locations are discovered, in operation604these empty device locations may be populated via automated or manual rework operations. In operation606the populated devices may then be permanently affixed to the device locations. For example, reflow, epoxy curing or another attachment process may be performed to affix placed devices into their device locations.

The terms “electronically coupled,” “electrically coupled,” and the like as used herein refers to any connection, coupling, link or the like by which electrical signals and/or power carried by one system element are imparted to the “coupled” element. Such “electronically coupled” devices, or signals and devices, are not necessarily directly connected to one another and may be separated by intermediate components or devices that may manipulate or modify such signals. Likewise, the terms “connected” or “coupled” as used herein in regard to mechanical or physical connections or couplings is a relative term and does not require a direct physical connection.

The present disclosure is directed to orientation-independent device configuration and assembly. An electronic device may comprise conductive pads arranged concentrically on a surface of the device. The conductive pads on the device may mate with conductive pads in a device location in circuitry. Example conductive pads may include at least a first circular conductive pad and a second ring-shaped conductive pad arranged to concentrically surround the first conductive pad. The concentric arrangement of the conductive pads allows for orientation-independent placement of the device in the circuitry. In particular, the conductive pads of the device will mate correctly with the conductive pads of the circuitry regardless of variability in device orientation. In one embodiment, the device may also be configured for use with fluidic self-assembly (FSA). For example, a device housing may be manufactured with pockets that cause the device to attain neutral buoyancy during manufacture.

The following examples pertain to further embodiments. According to one aspect there is provided a device. The device may comprise a device housing, at least one electronic component enclosed within the device housing and conductive pads structurally coupled to the device housing and electronically coupled to the at least one electronic component, the conductive pads being arranged concentrically on the device.

According to another aspect there is provided circuitry. The circuitry may comprise a substrate including at least one device location into which a device is populated during manufacture of the circuitry, the at least one device location including conductive pads structurally coupled to the substrate and electrically coupled to at least one circuit path in the substrate, the conductive pads being arranged concentrically on the substrate.

According to another aspect there is provided a method. The method may comprise populating circuitry with at least one device, the at least one device comprising conductive pads arranged concentrically on a surface of the at least one device to mate with conductive pads arranged concentrically at a device location in the circuitry and affixing the at least one device to the circuitry.