Devices with metal inlays

Abstract

A light emitting device is described herein. The light emitting device includes a hybrid device having a top surface and a bottom surface, a packaging substrate having a metal inlay in an opening in the packaging substrate, and a plurality of conductive vias. The metal inlay is thermally coupled to the bottom surface of the hybrid device. Conductive contacts are disposed on the bottom surface of the packaging substrate, each electrically coupled to one of the plurality of conductive vias. Conductive connectors are electrically coupled between the top surface of the hybrid device and the top surface of the packaging substrate. Each of the conductive connectors is electrically coupled to a respective one of the conductive contacts on the bottom surface of the packaging substrate by a respective one of the conductive vias.

Description

[Technical Field]

[0001] This application claims the benefit of U.S. Provisional Application No. 62 / 970,975, filed February 6, 2020, and U.S. Patent Application No. 16 / 934,905, filed July 21, 2020, which are incorporated herein by reference as if fully set forth. [Background technology]

[0002] Precision controlled lighting applications can require the production and manufacturing of miniature addressable light emitting diode (LED) lighting systems. The smaller size of such systems can require non-traditional components and manufacturing processes. Summary of the Invention

[0003] A light emitting device is described herein. The light emitting device includes a hybrid device having a top surface and a bottom surface, a packaging substrate having a metal inlay in an opening in the packaging substrate, and a plurality of conductive vias. The metal inlay is thermally coupled to the bottom surface of the hybrid device. Conductive contacts are disposed on the bottom surface of the packaging substrate, each electrically coupled to one of the plurality of conductive vias. Conductive connectors are electrically coupled between the top surface of the hybrid device and the top surface of the packaging substrate. Each of the conductive connectors is electrically coupled to a respective one of the conductive contacts on the bottom surface of the packaging substrate by a respective one of the conductive vias. [Brief explanation of the drawings]

[0004] A more detailed understanding will be had from the following description, given by way of example in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 is a top view of an example of an LED array. [Figure 2A] FIG. 1 is a cross-sectional view of an example hybrid device. [Figure 2B] 2B is a cross-sectional view of an example of an LED lighting system incorporating the example hybrid device of FIG. 2A. [Figure 3] FIG. 2C is a cross-sectional view of an example of an application system incorporating the LED lighting system of FIG. 2B. [Figure 4] FIG. 2C is a top view of the example LED lighting system of FIG. 2B. [Figure 5A] 5A, 5B, 5C, and 5D are top views of other example LED lighting systems showing example layouts of passive components, metallization, and other elements. [Figure 5B] 5A, 5B, 5C, and 5D are top views of other example LED lighting systems showing example layouts of passive components, metallization, and other elements. [Figure 5C] 5A, 5B, 5C, and 5D are top views of other example LED lighting systems showing example layouts of passive components, metallization, and other elements. [Figure 5D] 5A, 5B, 5C, and 5D are top views of other example LED lighting systems showing example layouts of passive components, metallization, and other elements. [Figure 6A] 6A, 6B, and 6C are top views of the topmost layers, ie, the first, second, and third layers, of an example four-layer circuit board. [Figure 6B] 6A, 6B, and 6C are top views of the topmost layers, ie, the first, second, and third layers, of an example four-layer circuit board. [Figure 6C] 6A, 6B, and 6C are top views of the topmost layers, ie, the first, second, and third layers, of an example four-layer circuit board. [Figure 6D] FIG. 2 is a bottom view of the bottom or fourth layer of an example four-layer circuit board. [Figure 7] 2C is a diagram of an example of a vehicle headlamp system that may incorporate the LED lighting system of FIG. 2B. [Figure 8] FIG. 2 is a diagram of another example of a vehicle headlamp system. [Figure 9] 2C is a flow diagram of an example method for manufacturing an LED lighting system, such as the LED lighting system of FIG. 2B. DETAILED DESCRIPTION OF THE INVENTION

[0005] Examples of several different optical illumination system and / or light emitting diode ("LED") implementations are described more fully below with reference to the accompanying drawings. These examples are not mutually exclusive, and features found in one example may be combined with features found in one or more other examples to achieve further implementations. Accordingly, it should be understood that the examples shown in the accompanying drawings are provided for illustrative purposes only and that they are not intended to limit the present disclosure in any way. Like elements are referred to with like numerals throughout.

[0006] It is understood that, although terms such as first, second, and third may be used herein to describe various elements, these elements should not be limited by these terms. These terms may be used to distinguish one element from another. For example, a first element may be referred to as a second element, and a second element may be referred to as the first element, without departing from the scope of the present invention. As used herein, the term "and / or" may include any and all combinations of one or more of the associated listed items.

[0007] It is understood that when an element, e.g., a layer, region, or substrate, is referred to as being "on" or extending "upon" another element, it may be directly on or extending directly onto the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, there may be no intervening elements present. It is also understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element and / or may be connected or coupled to the other element via one or more intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements between the element and the other element. It is understood that these terms are intended to encompass elements in different orientations in addition to the orientation depicted in the figures.

[0008] Relative terms such as "lower," "above," "upper," "bottom," "horizontal," or "vertical" may be used herein to describe the relationship of one element, layer, or region to another element, layer, or region as depicted in the figures. It is understood that these terms are intended to encompass devices in different orientations in addition to the orientation depicted in the figures.

[0009] Whether the LEDs, LED arrays, electrical components, and / or electronic parts are housed on one, two, or more electronics substrates may also depend on design constraints and / or application.

[0010] Among the most efficient light sources currently available are semiconductor light-emitting devices (LEDs), or light output emitting devices, such as devices that emit ultraviolet (UV) or infrared (IR) light output. These devices (hereinafter, "LEDs") can include light-emitting diodes, cavity-type light-emitting diodes, vertical-cavity laser diodes, edge-emitting lasers, or the like. LEDs can be attractive candidates for many different applications, for example, due to their small size and lower power requirements. For example, they can be used as light sources (e.g., flashlights and camera flashes) for handheld battery-powered devices such as cameras and mobile phones. They can also be used for, for example, automotive lighting, head-up display (HUD) lighting, horticultural lighting, street lighting, video torches, general lighting (e.g., home, store, office, and studio lighting, theater / stage lighting, and architectural lighting), augmented reality (AR) lighting, virtual reality (VR) lighting, as backlights for displays, and for IR spectroscopy. A single LED will provide light that is less bright than an incandescent light source, therefore, in applications where more brightness is desired or required, a multi-junction device or an array of LEDs (e.g., monolithic LED array, micro LED array, etc.) may be used.

[0011] LEDs may be arranged in an array for some applications. For example, LED arrays may support applications that benefit from fine-grained intensity, spatial, and temporal control of light distribution. This may include, but is not limited to, precise spatial patterning of emitted light from pixel blocks or individual pixels. Depending on the application, the emitted light may be spectrally distinct, adaptive over time, and / or environmentally responsive. LED arrays may provide pre-programmed orientation with varying intensity, spatial, or temporal patterns. The emitted light may be based at least in part on received sensor data and may be used for optical wireless communication. Associated electronics and optics may vary at the emitter level, emitter block level, or device level.

[0012] An LED array can be formed from a one-, two-, or three-dimensional array of LEDs, VCSELs, OLEDs, or other controllable light-emitting systems. The LED array can be formed as an emitter array on a monolithic substrate, by partial or complete segmentation of a substrate, using photolithographic, additive, or subtractive processes, or through assembly using pick-and-place or other suitable mechanical placement. The LED array can be uniformly arranged in a grid pattern or positioned to define a geometric structure, curve, random, or irregular layout.

[0013] Figure 1 is a top view of an example LED array 102. In the example shown in Figure 1, the LED array 102 is an array of emitters 120. The emitters 120 in the LED array 102 may be individually addressable or addressable in groups / subsets.

[0014] A 3x3 close-up of the LED array 102 is also shown in FIG. 1 . As shown in the 3x3 close-up, the LED array 102 may include a plurality of emitters 120, each having a width w1. In embodiments, the width w1 may be approximately 100 μm or less (e.g., 40 μm). The lanes 122 between the emitters 120 may be as wide as w2. In embodiments, the width w2 may be approximately 20 μm or less (e.g., 5 μm). In some embodiments, the width w2 may be as small as 1 μm. The lanes 122 may provide an air gap between adjacent emitters or may include other materials. The distance D1 from the center of one emitter 120 to the center of an adjacent emitter 120 may be approximately 120 μm or less (e.g., 45 μm). It is understood that the widths and distances provided herein are merely examples, and the actual widths and / or dimensions may vary.

[0015] It is understood that while Figure 1 depicts square emitters arranged in a symmetric matrix, any shape and arrangement of emitters may be used in the embodiments described herein. For example, the LED array 102 of Figure 1 may include over 20,000 emitters in any suitable arrangement, such as a 200x100 matrix, a symmetric matrix, an asymmetric matrix, or the like. It is also understood that multiple sets of emitters, matrices, and / or substrates may be arranged in any suitable configuration to implement the embodiments described herein.

[0016] As mentioned above, an LED array, such as LED array 102, can include up to 20,000 or more emitters. 2 These LEDs can have surface areas of 1000 W or more and can require significant power to power them, e.g., 60 Watts. LED arrays such as these may be referred to as micro LED arrays or simply micro LEDs. In some embodiments, micro LEDs may include hundreds, thousands, or even millions of LEDs or emitters arranged together on a centimeter-scale or smaller substrate. Micro LEDs may include an array of individual emitters provided on a substrate, or may be a single silicon wafer or die that is partially or fully divided into segments that form the emitters.

[0017] The controller may be coupled to selectively power subgroups of emitters in the LED array to provide different light beam patterns. At least some of the emitters in the LED array may be individually controlled via connected electrical wiring. In other embodiments, groups or subgroups of emitters may be controlled together. In some embodiments, the emitters may have different colors other than white. For example, at least four of the emitters may be an RGBY group of emitters.

[0018] LED array luminaires can include light fixtures that can be programmed to project different lighting patterns based on selective emitter activation and intensity control. Such luminaires can deliver multiple controllable beam patterns from a single lighting device without moving parts. Typically, this is done by adjusting the brightness of individual LEDs in a 1D or 2D array. Optics, whether shared or individual, can optionally direct the light to specific target areas. In some embodiments, the height of the LEDs, their supporting substrates and electrical wiring, and associated micro-optics can be less than 5 millimeters.

[0019] LED arrays, including LED arrays or μLED arrays, can be used to selectively and adaptively illuminate buildings or areas for improved visual display or to reduce lighting costs. Such LED arrays may also be used to project media facades for decorative motion or video effects. With tracking sensors and / or cameras, selective illumination of areas around pedestrians may be possible. Spectrally distinct emitters can be used to adjust the color temperature of the lighting and to support wavelength-specific horticultural lighting.

[0020] Street lighting is an important application that can greatly benefit from the use of LED arrays. A single type of LED array can be used to mimic various street light types, allowing for switching between, for example, a Type I linear street light and a Type IV semicircular street light by appropriately activating or deactivating selected emitters. Furthermore, street lighting costs can be reduced by adjusting the intensity or distribution of the light beam according to environmental conditions or time of use. For example, the light intensity and distribution area can be reduced when pedestrians are absent. If the emitters are spectrally distinct, the respective color temperatures of the lights can be adjusted according to daylight, twilight, or nighttime conditions.

[0021] LED arrays are also well suited to supporting applications requiring direct or projected displays. For example, warning signs, emergency signs, or information signs can all be displayed or projected using LED arrays. This allows, for example, color-changing or flashing exit signs to be projected. When the LED array contains multiple emitters, text or numerical information may be presented. Directional arrows or similar indicators may also be provided.

[0022] Vehicle headlamps are an LED array application requiring a large number of pixels and a high data refresh rate. Automotive headlights that actively illuminate only selected portions of the road can be used to mitigate problems associated with glare or dazzling for oncoming drivers. Using an infrared camera as a sensor, the LED array can activate only the emitters necessary to illuminate the road while deactivating emitters that may dazzle pedestrians or oncoming drivers. It can also selectively illuminate off-road pedestrians, animals, or signs to enhance the driver's environmental awareness. If the emitters are spectrally distinct, the respective color temperatures of the lights may be adjusted according to daylight, twilight, or nighttime conditions. Some emitters may also be used for optical wireless vehicle-to-vehicle communications.

[0023] A silicon backplane may be provided adjacent to the LED array to individually drive or control each LED or emitter in the array. In some embodiments, the silicon backplane may include: circuitry for receiving power from one or more sources to power various portions of the silicon backplane; circuitry for receiving image input from one or more sources to display an image via the LED array; circuitry for communication between the silicon backplane and an external controller (e.g., a vehicle headlamp controller, a general lighting controller, etc.); circuitry for generating signals, such as pulse-width modulation (PWM) signals, to control operation of each LED or emitter in the array based on the received image input and communications received from external sources; and multiple LED drivers for individually driving the LEDs or emitters in the array based on the generated signals. In embodiments, the silicon backplane may be a complementary metal-oxide semiconductor (CMOS) backplane, which may include as many drivers as there are LEDs or emitters in the corresponding LED array. In some embodiments, the silicon backplane may be an application-specific integrated circuit (ASIC). In some embodiments, one driver may be provided for any number of groups of LEDs or emitters, and control may be of groups of LEDs or emitters rather than individual. Each driver may be individually electrically coupled to a corresponding LED or emitter or group of LEDs or emitters. While silicon backplanes are described above with respect to specific circuits, those skilled in the art will understand that silicon backplanes used to drive LED arrays as described herein may include more, fewer, or different components potentially performing different functions without departing from the embodiments described herein.

[0024] As described above, individual drivers in a silicon backplane can be electrically coupled to individual LEDs or emitters or groups of LEDs or emitters in an LED array. Therefore, the LED array must be located in close proximity to the silicon backplane. In embodiments, this can be achieved by individually coupling copper pillar bumps or other connectors in an array of connectors on the surface of the LED array to corresponding connectors on the opposing surface of the silicon backplane. Silicon backplanes such as those described above can become very hot during operation, especially given their proximity to the LED array. Therefore, heat dissipation can be a challenge in such devices. While several solutions for heat dissipation in semiconductor devices are known, such solutions often involve structures that dissipate heat through the top of the device. However, due to the light emission from the LED array, heat dissipation through the top of the device may not be practical or possible. The embodiments described herein provide a structure that can enable effective and efficient heat dissipation through the bottom of the device.

[0025] Furthermore, an LED array, such as LED array 102, and an associated silicon backplane may require numerous passive components, such as resistors, capacitors, and crystals, to be placed on the circuit board in close proximity to the silicon backplane. In addition to providing heat dissipation through the bottom side of the device, the embodiments described herein may also provide an LED package that allows for the placement of numerous passive components (e.g., 27 or more) on the top side of the circuit board in close proximity to the backplane and LED array. The embodiments described herein may also provide a low-profile LED array package that can accommodate one or more passive components and allow for the dissipation of heat generated by the silicon backplane and LED array.

[0026] FIG. 2A is a cross-sectional view of an example hybrid device 200. In the example shown in FIG. 2A , the hybrid device 200 includes a silicon backplane 204. A first surface 203 of an LED array 202, e.g., μLEDs, can be mounted on a first surface 205 of the silicon backplane 204. For ease of explanation, the first surface 205 of the silicon backplane 204 may be referred to herein as the top surface, and the first surface 203 of the LED array 202 may be referred to herein as the bottom surface. However, one skilled in the art will understand that the first surface 205 can be the bottom surface when the hybrid device 200 is flipped over, the side surface when the hybrid device 200 is oriented on its side, etc. Similarly, the first surface 203 can be the top surface when the hybrid device 200 is flipped over, the side surface when the hybrid device 200 is oriented on its side, etc. As described above, an array of connectors (not shown) on the first surface 205 of the silicon backplane 204 may be soldered, reflowed, or otherwise electrically and mechanically coupled to the array of connectors on the bottom surface of the LED array 202. The array of connectors may be any array of connectors, such as an array of copper pillar bumps. The LED array 202 may have a depth D1. In embodiments, the depth D1 may be, for example, between 5 μm and 250 μm. The silicon backplane 204 may have a depth D2. In embodiments, the depth D2 may be, for example, between 100 μm and 1 mm. The hybrid device 200 may also be referred to as a hybrid die.

[0027] Figure 2B is a cross-sectional view of an example of an LED lighting system 250 incorporating the example hybrid device 200 of Figure 2A. In the example shown in Figure 2B, the hybrid device 200 is packaged within a packaging substrate 208.

[0028] In the example shown in FIG. 2B , the second surface 207 of the silicon backplane 204 may be mounted to the first surface 209 of the metal inlay 210. The second surface 207 of the silicon backplane 204 may be referred to herein as the bottom surface, and the first surface 209 of the metal inlay 210 may be referred to herein as the top surface. However, those skilled in the art will understand that the second surface 207 may be the top surface when the hybrid device 200 is flipped over, may be the side surface when the hybrid device 200 is turned on its side, etc. Similarly, the first surface 209 may be the bottom surface when the hybrid device is flipped over, may be the side surface when the hybrid device 200 is turned on its side, etc. In the example shown in FIG. 2B , the second surface 207 of the silicon backplane 204 and the first surface 209 of the metal inlay 210 are connected by the metal layer 206. Metal layer 206 may be any metal with good thermal properties that allows for heat transfer between silicon backplane 204 and metal inlay 210. In an embodiment, metal layer 206 may be silver. Metal layer 206 thermally couples silicon backplane 204 to metal inlay 210.

[0029] The metal inlay 210 can be one or more layers of one or more metals with good thermal properties. In embodiments, the metal inlay 210 is a single piece of metal, such as a piece or block of copper or aluminum. The metal inlay 210 can have a second surface 211 that can contact another circuit board, heat sink, or other metal inlay or piece (examples of which are described below) to aid in heat transfer from the LED array 202 and silicon backplane 204 through the metal inlay 210 to the circuit board, heat sink, or other inlay or piece. The second surface 211 of the metal inlay 210 is sometimes referred to herein as the bottom surface. However, those skilled in the art will understand that the second surface 211 can be the top surface when the hybrid device 200 is turned upside down, the side surface when the hybrid device 200 is turned on its side, etc. The metal inlay 210 can also include a side surface. Depending on the shape, the metal inlay 210 can have multiple sides or a single side, which can be a top surface, a bottom surface, etc., depending on the orientation of the hybrid device 200. A portion of the first and / or second surface 209 / 211 of the metal inlay 210 can be a conductive pad or can have a conductive pad coupled to it, the conductive pad can cover a portion of the first and / or second surface 209 / 211, the conductive pad can cover the entire first and / or second surface 209 / 211, or the conductive pad can extend beyond the first and / or second surface 209 / 211.

[0030] The metal inlay 210 may be embedded in the substrate 208. More specifically, in the illustrated embodiment, the metal inlay 210 is embedded in the substrate 208 such that the metal layer 206, the silicon backplane 204, and the LED array 202 extend above and protrude through a first surface 213 of the substrate 208. The first surface 213 is sometimes referred to herein as the top surface, but may be a side surface or a bottom surface depending on the orientation of the LED lighting system 250. In some embodiments, all or a portion of the metal layer 206 and / or the silicon backplane 204 may be embedded in the substrate 208. The substrate 208 may have an opening exposing inner surfaces 217 a, 217 b of the substrate 208. The opening may extend completely through the entire thickness T of the substrate 208. Depending on the shape, the opening may have multiple inner surfaces or a single inner surface 217, which may be the top surface, the bottom surface, etc. depending on the orientation of the LED lighting system 250. 2B, hybrid device 200 is positioned such that at least metal inlay 210 is within the opening and has its sides in contact with inner surfaces 217a, 217b of substrate 208. In such an embodiment, hybrid device 200 may be secured to inner surfaces 217a, 217b of substrate 208 via a suitable adhesive. In other embodiments, substrate 208 may be molded around hybrid device 200 such that at least the sides of metal inlay 210 are in direct contact with inner surfaces 217a, 217b of substrate 208. In other embodiments, the opening may be wider than hybrid device 200, leaving a space between inner surfaces 217a, 217b and at least the sides of metal inlay 210.

[0031] The illustrated LED lighting system 250 may also include a metal pad 218 thermally coupled to the second surface 211 of the metal inlay 210. The metal pad 218 may facilitate connection of the metal inlay 210 to other circuit boards, other metal inlays, and / or heat sinks. In embodiments, the metal pad 218 may not be included, and the metal inlay 210 may be placed in direct contact with other circuit boards, other metal inlays, and / or heat sinks. In the illustrated embodiment, the metal pad 218 completely covers the second surface 211 of the metal inlay 210 and overlaps a portion of the second surface 215 of the substrate 208. The second surface 211 is sometimes referred to herein as a bottom surface, but may also be a leaf surface, a side surface, etc. depending on the orientation of the LED lighting system 250. As will be understood by those skilled in the art, the metal pad 218 may only partially cover the second surface 211 of the metal inlay 210, may completely cover the second surface 211 of the metal inlay 210 without overlapping with the second surface 215 of the substrate, or may extend further to cover a larger area of ​​the second surface 215 of the substrate 208.

[0032] Passive components 216 may be mounted on a first surface 213 of the substrate 208. In the example shown in FIG. 2B , the passive components 216 are mounted to metal pads 221 on the first surface 213. Bottom metal pads or contacts 220 may also be provided on a second surface 215 of the substrate 208. Each of the passive components 216 may be coupled to a respective metal pad or contact 220 on the second surface 215 of the substrate 208 by a respective via 219. The vias 219 may include a metal material that is lined, filled, or otherwise electrically coupled between the metal pads 221 and the metal pads or contacts 220 to provide electrical connection between the passive components 216 and the metal pads or contacts 220 on the bottom surface of the substrate 208 for electrical connection to another circuit board (shown in FIG. 3 ). The silicon backplane 204 may also be electrically coupled to the passive components 216 via conductive connectors 212. 2B, metallization on the first surface 213 of the substrate 208 may complete the electrical connection between the conductive connectors 212 and the respective passive components 216. Examples of metallization are shown and described below in connection with FIG.

[0033] Although only two conductive connectors 212 are shown in FIG. 2B , any number of conductive connectors 212 may be included. For example, LED lighting system 250 may include 27 or more passive components 216 and a similar number of conductive connectors 212. In the illustrated embodiment, conductive connectors 212 are wires, such as ribbon wires. However, conductive connectors 212 may be any suitable type of conductive connector, such as a flexible circuit. The conductive connectors may be completely covered by an encapsulant 214. The encapsulant 214 may protect the conductive connectors 212 and, in embodiments, may also function to provide contrast, for example, for images displayed by LED array 202. In embodiments, the encapsulant may be an epoxy or silicone material with carbon fillers, which may create a dark or black appearance. This encapsulant may also be referred to herein as a light-tight encapsulant.

[0034] FIG. 3 is a cross-sectional view of an application system 300 incorporating the LED lighting system 250 of FIG. 2B . The application system 300 may include a circuit board 224 having a number of metal pads (not shown) on a first surface 301. The metal pads may be located at positions corresponding to the positions of the corresponding metal pads 218 and 220 of the LED lighting system 250. The circuit board 224 may also include a metal inlay 226, which may include a metal pad positioned to correspond to the metal pad 218 of the LED lighting system 250. The metal pads 218 and 220 of the LED lighting system 250 may be soldered to the corresponding metal pads on the circuit board 224. A layer of solder 222 is shown as a uniform layer between the second surface 211 of the substrate 208 and the first surface 301 of the circuit board 224. However, in embodiments, the solder 222 may be located only between the corresponding metal pads and / or may extend slightly over or not completely cover the metal pads. The placement of the metal inlay 210 of the LED lighting system 250 in close proximity to and thermally coupled with the circuit board 224, and particularly the metal inlay 226 in the circuit board 224, if included, may allow for good heat transfer from the hybrid device 200 to the circuit board 224 via the LED array 202, the silicon backplane 204, and the second or bottom surfaces 203, 207, and 211 of the metal inlay 210. The first surface 301 of the substrate 224 is sometimes referred to herein as the top surface, but may also be the bottom surface, side surface, etc., depending on the orientation of the application system 300.

[0035] Additionally, electrical coupling between metal pads 220 and corresponding metal pads on circuit board 224 may enable electrical coupling between passive components 216, silicon backplane 204, and circuit board 224. Circuit board 224 may be part of a larger system used in a particular application, such as a vehicle lighting or flashing application (an example vehicle lighting system is described below in connection with FIGS. 7 and 8). In addition to heat sink 230, circuit board 224 may include other circuit elements necessary for the larger system.

[0036] In embodiments, the metal inlay 226 may be disposed within the circuit board 224 in any of the manners described above with respect to the metal inlay 210 of the LED lighting system 250. The circuit board 224 may also be thermally coupled to a heat sink 230 for further heat dissipation. A second surface 303 of the circuit board 224 may be attached to a first surface 305 of the heat sink 230 via a thermal interface material (TIM) 228. Herein, the second surface 303 may also be referred to as a bottom surface, and the first surface 305 may also be referred to as a top surface, although they may each be a bottom surface, a top surface, a side surface, etc. depending on the orientation of the application system 300.

[0037] Figure 4 is a top view showing the top surface 400 of the LED lighting system 250 of Figure 2B. The top view shows the first or top surface of the LED array 202, the first or top surface 205 of the silicon backplane 204 that is not covered by the LED array 202, the encapsulant 214 that covers the conductive connectors 212, the passive components 216, metallization 232 that electrically couples the conductive connectors 212 to respective ones of the passive components 216, and the first or top surface 213 of the substrate 208 that is not covered by the silicon backplane 204, the encapsulant 214, the metallization 232, and the passive components 216. Although not shown in Figure 4, the conductive connectors 212 can be electrically coupled to metal pads on the first surface 213 of the substrate 208, and the metallization 232 can be a layer of metal that is patterned or etched to form electrical connections between the metal pads (not shown) and the passive components 216.

[0038] As shown in FIG. 4, the LED lighting system 250 has a length l1 and a width w1. In an embodiment, the length l1 may be approximately 30 mm, and the width w1 may be approximately 22 mm. The silicon backplane 204 may have a length l2 and a width w2 (not labeled for clarity). In an embodiment, the length l2 may be approximately 15.5 mm, and the width w2 may be approximately 6.5 mm. The LED array 202 may have a length l3 and a width w3. In an embodiment, the length l3 may be approximately 11 mm, and the width w3 may be approximately 4.4 mm.

[0039] Given these example dimensions, a relatively large surface area (660 mm in the example above) 2 ), of which a relatively large portion is the LED array (approximately 100mm in the example above). 2 Therefore, this design provides sufficient space for mounting passive electronic components on the LED array package.

[0040] As described above, a silicon backplane may include: circuitry for receiving power from one or more sources to power various portions of the silicon backplane; circuitry for receiving image input from one or more sources to display an image via an LED array; circuitry for communication between the silicon backplane and an external controller (e.g., a vehicle headlamp controller, a general lighting controller, etc.), such as circuitry for generating signals, e.g., pulse-width modulation (PWM) signals, to control operation of individual LEDs or emitters in the array based on the received image input and communications received from external sources; and multiple LED drivers for individually driving the LEDs or emitters in the array based on the generated signals. For communication, the silicon backplane may have multiple digital interfaces, which may require multiple (e.g., 100 or more) physical connection input / output (I / O) pins to connect to either passive components on substrate 208 or to an external circuit board, such as a control board. In some embodiments, the external board or device may be a vehicle headlamp that may be communicatively coupled to various control modules within the automobile to receive control signals.

[0041] Furthermore, the silicon backplane may require multiple external power sources (e.g., two or more) to power the hybrid device. In embodiments, the hybrid device may include groups of I / O pins corresponding to two or more power sources, such as a digital power source, an analog power source, and an LED power source. Each external power source may require one or more passive components located in close proximity to the corresponding I / O pin (e.g., within 10 mm of at least one of the I / O pins). In embodiments, such passive components may include at least one individual decoupling capacitor, and in some cases, five or more decoupling capacitors. Furthermore, the silicon backplane may require resistors to accurately set the LED current, capacitors other than the decoupling capacitors, and / or crystals to set the frequency for a universal asynchronous receiver-transmitter (UART). Many or all of these passive components should be located as close as possible to the silicon backplane pins (e.g., within 10 mm of at least one of the I / O pins). For example, the crystal used to set the frequency for a UART may have a very high frequency, which may be sensitive to noise. Additionally, each of these passive components may need to be electrically coupled to the silicon backplane, which may make space on the substrate 208 challenging.

[0042] In embodiments, passive components that need to be located close to the I / O pins of the silicon backplane may be mounted on the top surface of the packaging substrate 208. In embodiments, all passive components supporting the silicon backplane may be mounted on the packaging substrate 208, while in other embodiments, some passive components (e.g., those that can be spaced further from the I / O pins of the silicon backplane) may be mounted on another circuit board, such as a control board. As mentioned above, the silicon backplane 204 may use conductive connectors 212, such as ribbon wires or flexible circuits, to make the potentially numerous electrical connections between the silicon backplane 204 and the substrate 208. This saves space on the substrate 208 that can be used for the passive components themselves and for other routing, as described in more detail below. Furthermore, in the case of micro LEDs, large key currents, such as 17 A, may be required. Routing such large currents may require large traces. To accommodate routing for passive components and save space on the packaging substrate for passive components, a multi-layer substrate structure is described below, where each layer has a different function. This allows, for example, the use of large traces for routing high currents, while also allowing analog and digital grounds to be properly separated on different layers.

[0043] 5A, 5B, 5C, and 5D are top views 500A, 500B, 500C, and 500D of another example LED lighting system showing an example layout of passive components, metallization, and other elements. Figure 5D shows an example layout of passive components 216 and some of the surface metallization and board through connections (e.g., vias).

[0044] In the example shown in FIG. 5D , 27 passive components 216a-216zz are mounted on the first surface 213 of the substrate 208. However, those skilled in the art will understand that more or fewer passive components 216 may be mounted on the substrate without departing from the embodiments described herein. As discussed above, for example, all of the passive components supporting the silicon backplane may be located on the first surface 213 of the substrate 208, or some of the passive components supporting the silicon backplane may be located on the first surface 213 of the substrate 208 while others are mounted on another circuit board, such as a control board. The passive components may include, for example, capacitors (decoupling or non-decoupling), resistors, and / or crystals, as discussed above, or may include other types of passive components not specifically mentioned. In the central region of the substrate 208, an LED array 202 is shown mounted on the silicon backplane 204.

[0045] For clarity, the conductive connectors 212 are not shown in FIG. 5D . However, the pins 506 to which the conductive connectors 212 are soldered or otherwise electrically coupled are shown. In other words, the pins 506 can be electrically coupled to corresponding I / O pins (not shown) of the silicon backplane 204. Although the I / O pins of the silicon backplane are not shown in FIG. 5D , they can correspond to the locations in FIGS. 2A-2C where, for example, the conductive connectors 212 are attached to the top surface of the silicon backplane 204. As shown in FIG. 5D , the pins 506 can be routed to the passive components 216 a - 216 zz by the metallization 232 and can be routed to other components or layers by the metallization 502. At least some of the passive components 216 a - 216 zz should be in proximity to the I / O pins (not shown) of the silicon backplane 204. For example, passive components 216 a - 216 zz may be within 10 mm of at least one of the I / O pins of silicon backplane 204 .

[0046] In Figure 5D, one metallization 502 is labeled and electrically coupled to via 504, and one metallization 232 is labeled and electrically coupled to one of the passive components 216zz. The routing of via 504 is shown on each of the four layers of an example four-layer circuit board structure in Figures 6A, 6B, 6C, and 6D below. Example locations of groups of pins 506 for receiving from three example power sources are also labeled in Figure 5D, including, for example, digital power location or group 508, LED power location or group 510, and analog power location or group 512, and corresponding passive components or passive component groups (e.g., passive components 216y, 216z, 216zz, 216a, 216b, 216c, 216d, 216e, 216f, 216g, and 216h, although more or fewer of these passive components may be used for various power sources). The groups of pins 506 may correspond to corresponding groups of I / O pins (not shown) on a silicon backplane.

[0047] Figures 5A, 5B, and 5C show additional surface metallization that may be used for routing. Figure 5A shows a positive power trace 520, including a corresponding metal pad. Figure 5B shows a ground trace 530 for digital ground (located on a separate layer). Figure 5C shows an analog ground 540 that is separate from the digital ground, located on a separate layer. While specific layouts are shown in Figures 5A, 5B, 5C, and 5D, one skilled in the art will recognize that multiple different layouts are possible, consistent with the embodiments described herein.

[0048] Figures 6A, 6B, and 6C are top views 600A, 600B, and 600C of the top, first, second, and third layers of an example four-layer circuit board. Figure 6D is a bottom view 600D of the bottom, fourth, layer of an example four-layer circuit board.

[0049] Figure 6A is a top view 600A of the top or first layer of an example four-layer circuit board. This top or first layer may be similar to the first surface 213 of the substrate 208 shown in Figures 5A, 5B, 5C, and 5D. Figure 6A particularly shows the LED array 202, the silicon backplane 204, and various surface routing. Board through connections (e.g., vias) 504 are also labeled in Figure 6A to show the correspondence between the board through connections 504 in Figures 6A, 6B, 6C, and 6D.

[0050] FIG. 6B is a top view 600B of the second layer of an example four-layer circuit board. As mentioned above, each layer of a multi-layer circuit board may perform a different function. In an embodiment, the second layer shown in FIG. 6B may be for control signal routing and may include traces 550 that may perform that function. Board feedthroughs 504 are also labeled. As shown in FIG. 6B, a portion of the metal inlay 210 may extend through the example second layer shown in FIG. 6B.

[0051] FIG. 6C is a top view 600C of the third layer of an example four-layer circuit board. In an embodiment, the third layer may include a digital ground plane 560, which may be separated from the analog ground 540 of the top or first layer, as described above. The digital ground plane 560 may function as a ground connection for the digital blocks of the silicon backplane and as an EMC shield. This may avoid ground bouncing between the analog and digital circuits, which could otherwise cause electromagnetic compatibility (EMC) issues and circuit malfunctions. The board feedthroughs 504 are also labeled. As shown in FIG. 6C, a portion of the metal inlay 210 may extend through the example third layer shown in FIG. 6C.

[0052] Figure 6D is a bottom view 600D of the bottom or fourth layer of an example four-layer circuit board. The bottom or fourth layer may represent the second surface 215 of the substrate 208 of Figure 2B. Figure 6D also shows the second surface 211 of the metal inlay 210. Metal pads 218 may be attached to this surface of the metal inlay 210 (not shown in Figure 6D). Figure 6D shows metal traces 570, which may include metal contacts 220 in the embodiment of Figure 2B. These may be electrically coupled to passive components 216 by board feedthroughs 504 or possibly other vias, and may optionally be electrically coupled to other traces or components on the top or first layer.

[0053] Although Figures 6A-6D specifically illustrate a four-layer circuit board, the four-layer circuit board may be implemented as a multi-layer circuit board having fewer or more layers than four, depending, for example, on the number of external power supplies, digital interfaces, passive components, or potentially other features included.

[0054] Figure 7 is a diagram of an example vehicle headlamp system 700 that may incorporate, for example, LED lighting system 250 of Figure 2B. The example vehicle headlamp system 700 shown in Figure 7 includes a power line 702, a data bus 704, an input filter and protection module 706, a bus transceiver 708, a sensor module 710, an LED direct current to direct current (DC / DC) module 712, a logic low dropout (LDO) module 714, a microcontroller 716, and an active headlamp 718. In an embodiment, the active headlamp 718 may include an LED lighting system such as, for example, LED lighting system 250 of Figure 2B.

[0055] The power line 702 can have an input for receiving power from the vehicle, and the data bus 704 can have inputs / outputs through which data can be exchanged between the vehicle and the vehicle headlamp system 700. For example, the vehicle headlamp system 700 can receive commands, such as commands to turn on turn signals or turn on headlamps, from elsewhere in the vehicle and can transmit feedback to elsewhere in the vehicle if desired. A sensor module 710 can be communicatively coupled to the data bus 704 and can provide additional data to the vehicle headlamp system 700 or elsewhere in the vehicle, for example, related to environmental conditions (e.g., time of day, rain, fog, or ambient light levels), vehicle status (e.g., parked, moving, speed, or direction of travel), and the presence / location of other objects (e.g., vehicles or pedestrians). A headlamp controller separate from the vehicle controller communicatively coupled to the vehicle data bus can also be included in the vehicle headlamp system 700. In FIG. 7 , the headlamp controller can be a microcontroller, such as microcontroller (μc) 716. The microcontroller 716 may be communicatively coupled to the data bus 704 .

[0056] The input filter and protection module 706 may be electrically coupled to the power line 702 and may support various filters to, for example, reduce conducted emissions and provide power immunity. Additionally, the input filter and protection module 706 may provide electrostatic discharge (ESD) protection, load dump protection, alternator field decay protection, and / or reverse polarity protection.

[0057] An LED DC / DC module 712 may be coupled between the filter and protection module 706 and the active headlamp 718 to receive the filtered power and provide drive current to power the LEDs in the LED array of the active headlamp 718. The LED DC / DC module 712 may have an input voltage between 7 and 18 volts, with a nominal voltage of approximately 13.2 volts, and an output voltage that may be slightly (e.g., 0.3 volts) higher than the maximum voltage for the LED array (determined, for example, by factory or field calibration and operating conditioning due to load, temperature, or other factors).

[0058] The logic LDO module 714 may be coupled to the filter and protection module 706 to receive the filtered power. The logic LDO module 714 may also be coupled to the microcontroller 716 and the active headlamps 718 to provide power to the silicon backplane (e.g., CMOS logic) within the microcontroller 716 and / or the active headlamps 718.

[0059] The bus transceiver 708 may have, for example, a universal asynchronous receiver / transmitter (UART) or a serial peripheral interface (SPI) and may be coupled to a microcontroller 716. The microcontroller 716 may translate vehicle input based on or including data from the sensor module 710. The translated vehicle input may include a video signal that can be transferred to an image buffer within the active headlamp module 718. Additionally, the microcontroller 716 may load a default image frame at startup to check for open / short pixels. In embodiments, the SPI interface may load the image buffer into CMOS. The image frame may be a full frame, a differential frame, or a partial frame. Other functions of the microcontroller 716 may include control interface monitoring of CMOS status, including die temperature, and logic LDO outputs. In embodiments, the LED DC / DC output may be dynamically controlled to minimize headroom. In addition to providing image frame data, other headlamp functions may also be controlled, such as auxiliary use in conjunction with sidelights or turn signals and / or activation of daytime running lights.

[0060] Figure 8 is a diagram of another example vehicle headlamp system 800. The example vehicle headlamp system 800 shown in Figure 8 includes an application platform 802, two LED lighting systems 806 and 808, and optical systems 810 and 812. The two LED lighting systems 806 and 808 may be LED lighting systems such as LED lighting system 250 of Figure 2B, or may include LED lighting system 250 plus some or all of the other modules in vehicle headlamp system 700 of Figure 7. In the latter embodiment, LED lighting systems 806 and 808 may be vehicle headlamp subsystems.

[0061] LED lighting system 808 may emit light beam 814 (shown between arrows 814a and 814b in FIG. 8 ). LED lighting system 806 may emit light beam 816 (shown between arrows 816a and 816b in FIG. 8 ). In the embodiment shown in FIG. 8 , secondary optics 810 is adjacent to LED lighting system 808, and light emitted from LED lighting system 808 passes through secondary optics 810. Similarly, secondary optics 812 is adjacent to LED lighting system 806, and light emitted from LED lighting system 806 passes through secondary optics 812. In alternative embodiments, secondary optics 810 / 812 may not be provided in the vehicle headlamp system.

[0062] When included, secondary optics 810 / 812 may be or include one or more light guides. The one or more light guides may be edge-lit or may have an internal opening defining the inner edge of the light guide. The internal openings of the one or more light guides may accommodate LED lighting systems 808 and 806 (or active headlamps of a vehicle headlamp subsystem) that inject light into the inner edge (inner-opening light guides) or outer edge (edge-lit light guides) of the one or more light guides. In embodiments, the one or more light guides may shape the light emitted by LED lighting systems 808 and 806 as desired, such as to have a gradient, a chamfered distribution, a narrow distribution, a wide distribution, or an angular distribution.

[0063] Application platform 802 may provide power and / or data to LED lighting systems 806 and / or 808 via lines 804, which may include one or more or portions of power lines 702 and data bus 704 of Figure 7. There may be one or more sensors (which may be sensors within example vehicle headlamp system 700 or other additional sensors) inside or outside the housing of application platform 802. Alternatively, or in addition, as shown in example vehicle headlamp system 700 of Figure 7, each LED lighting system 808 and 806 may include its own sensor module, connectivity and control module, power module, and / or LED array.

[0064] In an embodiment, vehicle headlamp system 800 may represent an automobile with a steerable light beam, where LEDs may be selectively operated to provide the steerable beam. For example, an array of LEDs (e.g., LED array 102) may be used to define or project a shape or pattern, or to illuminate only selected sections of a road. In an example embodiment, infrared cameras or detector pixels in LED lighting systems 806 and 808 may be sensors (e.g., similar to the sensors in sensor module 710 of FIG. 7) that identify portions of a scene (e.g., a road or a crosswalk) that require illumination.

[0065] FIG. 9 is a flow diagram of an example method 900 for manufacturing an LED lighting system, such as LED lighting system 250 of FIG. 2B.

[0066] In the example method 900 of FIG. 9 , a thermally conductive inlay may be embedded in a first substrate (902). In embodiments, this may be done by placing the thermally conductive inlay within an opening in the first substrate. In some embodiments, the thermally conductive inlay may be adhered to an exposed inner surface of the substrate using an adhesive or may be press-fit. In some embodiments, the substrate may be molded around the thermally conductive inlay. Passive components may be surface mounted on the first substrate (904). In embodiments, passive components may be mounted, for example, by soldering, to at least some of the multiple metal contacts on a first or top surface of the first substrate. In embodiments, vias and other surface metallization may already be formed in the first substrate when the thermally conductive inlay is embedded, or the vias and other surface metallization may be formed later.

[0067] An LED array, such as a micro LED array, may be attached to a first or top surface of the silicon backplane (906). In embodiments, the LED array may include an array of connectors, such as copper pillar bumps, which may be individually coupled to drivers in the silicon backplane by soldering, reflow, or other methods. A thermally conductive material may be dispensed onto the first substrate (908). In embodiments, the thermally conductive material may be dispensed at least on metal pads attached to or part of a thermally conductive inlay. In other embodiments, the thermally conductive material may be dispensed directly onto at least the thermally conductive inlay. In some embodiments, the thermally conductive material may cover the entire first or top surface of the first substrate. In embodiments, the thermally conductive material may be silver. The backplane with the attached LED array may be die-attached to the first substrate (910), for example, by placing it on the thermally conductive material and allowing it to harden.

[0068] A backplane may be wirebond attached to the first substrate (912). This may be done, for example, by soldering or otherwise electrically coupling metal contacts, pads, or pins on the backplane to metal contacts, pads, or pins on the first or top surface of the first substrate using a ribbon wire, flexible circuit, or other connector. An encapsulant material, such as those described in detail above, may be dispensed onto or molded around the wirebonds (e.g., ribbon wire, flexible circuit, or other conductive connector) (914). In embodiments, this may result in the wirebonds being completely covered by the encapsulant material.

[0069] The first substrate may be surface mounted on the second substrate (916). In embodiments, metal pads or contacts on the second or bottom surface of the first substrate may be soldered or otherwise electrically coupled to metal pads or contacts on the first or top surface of the second substrate. Additionally, in some embodiments, a thermally conductive inlay embedded in the second substrate may be thermally coupled to a thermally conductive inlay embedded in the first substrate, for example, by soldering pads or portions thereof on both thermally conductive inlays together or by directly soldering the thermally conductive inlays together. The second substrate may be attached to the first or top surface of the heat sink (918), for example, using a thermal interface material (TIM).

[0070] Although the embodiments have been described in detail, those skilled in the art will appreciate that, given this specification, modifications may be made to the embodiments described herein without departing from the spirit of the inventive concept, and therefore, it is not intended that the scope of the invention be limited to the specific embodiments shown and described.

Claims

1. a hybrid device having a top surface and a bottom surface; a packaging substrate having a metal inlay in an opening of the packaging substrate and a plurality of conductive vias, the metal inlay thermally coupled to the bottom surface of the hybrid device; a plurality of conductive contacts on a bottom surface of the packaging substrate, each electrically coupled to one of the plurality of conductive vias; a first plurality of conductive contacts on a top surface of the packaging substrate, each electrically coupled to one of the plurality of conductive contacts on the bottom surface of the packaging substrate by one of the plurality of conductive vias; a second plurality of conductive contacts on the top surface of the packaging substrate, each electrically coupled to one of the plurality of conductive contacts on the bottom surface of the packaging substrate by one of the plurality of conductive vias; a plurality of conductive connectors, each electrically coupled between the top surface of the hybrid device and one of the first plurality of conductive contacts on the top surface of the packaging substrate; a plurality of passive electronic components, each disposed on one of the second plurality of conductive contacts on the top surface of the packaging substrate; and the hybrid device having a silicon backplane and a monolithic array attached to the silicon backplane via an array of bumps, the monolithic array having a plurality of light emitting segments; device.

2. The device of claim 1 , wherein a side of the metal inlay contacts an inner surface of the opening in the packaging substrate.

3. 3. The device of claim 2, wherein the silicon backplane comprises a plurality of drivers, one of the plurality of drivers electrically coupled to provide a drive current to one or a subset of the plurality of light-emitting segments.

4. 3. The device of claim 2, wherein the plurality of light-emitting segments comprises at least 20,000 light-emitting segments spaced 20 μm or less apart.

5. The device of claim 1 further comprising a layer of thermally conductive metallic material between the top surface of the metallic inlay and the bottom surface of the hybrid device.

6. The device of claim 1 , wherein the metal inlay comprises a solid copper material embedded in the packaging substrate.

7. The device of claim 1 , wherein the plurality of conductive contacts on the bottom surface of the packaging substrate are an interface to an external control board.

8. 10. The device of claim 1, further comprising at least one metallization layer on the top surface of the packaging substrate electrically coupled between the plurality of conductive connectors and the plurality of conductive vias.

9. a control board, The top surface and The bottom and a control circuit on the control board; a plurality of first conductive contacts on the top surface; a first metal inlay within the top surface opening; a control board having a light emitting device package, a hybrid device on the top surface of a packaging substrate; a plurality of second conductive contacts on a bottom surface of the packaging substrate; a second metal inlay embedded in the top surface of the packaging substrate; a light emitting device package having and the hybrid device includes a silicon backplane and a monolithic array attached to the silicon backplane via an array of bumps, the monolithic array having a plurality of light emitting segments; the bottom surface of the packaging substrate is disposed on the top surface of the control board, and the first conductive contacts on the top surface of the control board are electrically coupled to the second conductive contacts on the bottom surface of the packaging substrate. device.

10. the light emitting device package further comprising a plurality of conductive connectors electrically coupled between a top surface of the hybrid device and the top surface of the packaging substrate; the packaging substrate further includes a plurality of conductive vias, each of the plurality of conductive vias electrically coupled between a respective one of the plurality of conductive connectors and a respective one of the plurality of second conductive contacts on the bottom surface of the packaging substrate; 10. The device of claim 9.

11. The device of claim 10 , wherein the plurality of conductive connectors are one of a wire, a ribbon wire, and a flexible circuit.

12. The device of claim 10 further comprising a light-tight encapsulation covering the plurality of conductive connectors.

13. 13. The device of claim 12, wherein the light-tight encapsulant is one of silicone or epoxy with a carbon filler.

14. 10. The device of claim 9, wherein the silicon backplane comprises a plurality of drivers, one of the plurality of drivers electrically coupled to provide a drive current to one or a subset of the plurality of light-emitting segments.

15. 10. The device of claim 9, wherein the plurality of light-emitting segments comprises at least 20,000 light-emitting segments spaced 20 μm or less apart.

16. 10. The device of claim 9, further comprising a layer of thermally conductive metallic material between the top surface of the second metallic inlay and the bottom surface of the hybrid device.

17. 10. The device of claim 9, wherein the second metal inlay comprises a solid copper material embedded in the packaging substrate.

18. a hybrid device having a top surface and a bottom surface, the hybrid device having a silicon backplane and a monolithic array attached to the silicon backplane via an array of bumps, the monolithic array having a plurality of light emitting segments; a packaging substrate having a metal inlay in an opening of the packaging substrate and a plurality of conductive vias, the metal inlay thermally coupled to the bottom surface of the hybrid device; a plurality of conductive contacts on a bottom surface of the packaging substrate, each electrically coupled to one of the plurality of conductive vias; a plurality of conductive connectors electrically coupled between the top surface of the hybrid device and the top surface of the packaging substrate, each of the plurality of conductive connectors electrically coupled to a respective one of the plurality of conductive contacts on the bottom surface of the packaging substrate by a respective one of the plurality of conductive vias; a light-tight encapsulant covering the plurality of conductive connectors; A device having

19. 20. The device of claim 18, wherein the light-tight encapsulant is one of a silicone or an epoxy with a carbon filler.

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