Silicon-based cooling package for light-emitting devices

Various embodiments of a thermal energy transfer apparatus that removes thermal energy from a light-emitting device are described. In one aspect, an apparatus comprises a non-metal base plate and a silicon-based cover element disposed on the base plate. The base plate is coated with a first electrically-conductive pattern that forms a first electrode. The base plate is further coated with a second electrically-conductive pattern that is electrically isolated from the first electrically-conductive pattern. The cover element holds the one or more light-emitting devices between the base plate and the cover element with at least a portion of a light-emitting surface of each of the one or more light-emitting devices exposed. The cover element is coated with a third electrically-conductive pattern that is in contact with the second electrically-conductive pattern to form a second electrode when the cover element is disposed on the base plate.

TECHNICAL FIELD

The present disclosure generally relates to the field of transfer of thermal energy and, more particularly, to removal of thermal energy from a light-emitting device.

BACKGROUND

Light-emitting devices, such as vertical-cavity surface-emitting lasers (VCSEL), light-emitting diodes (LED), laser diodes and the like, generate thermal energy, or heat, when in operation. The heat generated by a light-emitting device needs to be removed, or dissipated, from the light-emitting device in order to allow the light-emitting device to achieve optimum performance while keeping the light-emitting device within a safe operating temperature range. With the form factor of light-emitting devices and the applications they are implemented in becoming ever more compact, it is imperative to effectively dissipate the high-density heat generated in an area of small footprint to ensure the safe operation and optimum performance of light-emitting devices.

Many metal-based heat dissipation packages, whether water-cooled or air-cooled, have been developed for use in compact packages to dissipate heat generated by light-emitting devices. For instance, heat exchangers and heat pipes made of a material with high thermal conductivity, such as copper, copper-tungsten alloy, aluminum or iron, for example, are commercially available. However, most metal-based heat exchangers and heat pipes experience oxidation, corrosion and/or crystallization after long periods of operation. Such fouling factors significantly reduce the efficiency of heat transfer of metal-based cooling packages. Other problems associated with metal-based cooling packages include, for example, difficulty in precision alignment in mounting laser diode bars, VCSELs or LEDs or chips in laser diode/VCSEL/LED cooling applications, issues with overall compactness of the package, corrosion of the metallic material in water-cooled applications, difficulty in manufacturing, etc. Yet, increasing demand for higher power density in small form factor motivates the production of a compact cooling package with fewer or none of the aforementioned issues. Moreover, conventional packages typically use wire bonding to provide electrical power to the light-emitting device, but wire bonding may add cost and complexity in manufacturing and may be prone to defects in addition to occupying space unnecessarily.

SUMMARY

This section highlights select features of the present disclosure, and is not to be interpreted as limiting scope of the claimed subject matter. Various embodiments of a silicon-based thermal energy transfer apparatus, or a cooling package, for light-emitting devices are described herein. The novel and non-obvious silicon-based thermal energy transfer apparatus provides a compact form factor, achieves better thermal conductivity than conventional metal-based cooling packages, and is more cost effective. The thermal energy transfer apparatus advantageously removes thermal energy from a light-emitting device and allows electrical power to be provided to the light-emitting device without using wire bonding.

According to one aspect, an apparatus may include a non-metal base plate and a silicon-based cover element. The base plate may be configured to receive one or more light-emitting devices therein. A first area of the base plate may be coated with a first electrically-conductive pattern that forms a first electrode for powering the one or more light-emitting devices. A second area of the base plate may be coated with a second electrically-conductive pattern that is electrically isolated from the first electrically-conductive pattern. The cover element may be configured to be disposed on the base plate to hold the one or more light-emitting devices between the base plate and the cover element with at least a portion of a light-emitting surface of each of the one or more light-emitting devices exposed. An area of the cover element may be coated with a third electrically-conductive pattern that is in contact with the second electrically-conductive pattern to form a second electrode together with the second electrically-conductive pattern for powering the one or more light-emitting devices when the cover element is disposed on the base plate.

In some embodiments, the base plate may include silicon, metal-core printed circuit board (PCB), ceramics, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal.

In some embodiments, the cover element may have a first primary surface and a second primary surface opposite the first primary surface thereof with the first primary surface of the cover element facing the base plate and the one or more light-emitting devices. The second primary surface of the cover element may include a plurality of grooves.

In some embodiments, the base plate may include a first primary surface and a second primary surface opposite to the first primary surface. The first primary surface may include: a non-recessed area and a recess configured to receive the one or more light-emitting devices in the recess, at least a portion of the recess and a first portion of the non-recessed area contiguously coated with the first electrically-conductive pattern, and a second portion of the non-recessed area coated with the second electrically-conductive pattern. The cover element may include a first primary surface and a second primary surface opposite to the first primary surface. The first primary surface of the cover element may be coated with the third electrically-conductive pattern that is configured to be in contact with the second electrically-conductive pattern when the cover element is disposed on the base plate with the first primary surface of the cover element facing the first primary surface of the base plate.

In some embodiments, the recess may include a main portion and a channel portion with the main portion dimensioned to receive the one or more light-emitting devices therein. A first part of the first electrically-conductive pattern may be disposed in the main portion and the channel portion of the recess. A second part of the first electrically-conductive pattern that is contiguous with the first part of the first electrically-conductive pattern may be disposed on the first portion of the non-recessed area of the first primary surface of the base plate. The cover element may be configured to be not in contact with the second part of the first electrically-conductive pattern when the cover element is disposed on the base plate.

In some embodiments, the apparatus may further include a layer of thermally-conductive material disposed on a non-recessed area of the base plate and configured to be in contact with the cover element when the cover element is disposed on the base plate such that the layer of thermally-conductive material functions as a thermal path to transfer thermal energy between the cover element and the base plate.

In some embodiments, the layer of thermally-conductive material may include diamond, copper, tin, silver or carbon nanotubes.

In some embodiments, the apparatus may further include a layer of metallic material disposed on at least a portion of the second primary surface of the base plate. The metallic material may bond the base plate to an external object.

In some embodiments, the apparatus may further include a collimating element disposed on the cover element. The collimating element may include a lens portion that collimates light emitted from the one or more light-emitting devices along a predefined direction.

In some embodiments, the collimating element may be made of glass, polymer, or quartz.

In some embodiments, the apparatus may further include a spacer element disposed on the collimating element with the collimating element disposed between the spacer element and the cover element. The spacer element may include an opening that accommodates at least the lens portion of the collimating element and may allow the light emitted from the one or more light-emitting devices to propagate through the spacer element.

In some embodiments, the spacer element may be made of silicon or ceramic.

In some embodiments, the apparatus may further include a window element disposed on the spacer element with the spacer element disposed between the window element and the collimating element. The window element may be substantially transparent.

In some embodiments, the apparatus may further include the one or more light-emitting devices received on the base plate. The one or more light-emitting devices may be disposed between the base plate and the cover element and configured to receive electrical power from the first electrode and the second electrode to emit light. The one or more light-emitting devices may include one or more vertical-cavity surface-emitting laser (VCSEL) or one or more light-emitting diodes (LED).

In some embodiments, the apparatus may further include an integrated circuit (IC) device disposed on the base plate and configured to receive electrical power from the first electrode and the second electrode to control operations of the one or more light-emitting devices.

In some embodiments, the apparatus may further include a silicon-based heat sink disposed on the IC device. The heat sink may include a first primary surface and a second primary surface opposite the first primary surface thereof with the first primary surface of the heat sink facing the IC device. The second primary surface of the heat sink may include a plurality of grooves.

According to another aspect, an apparatus may include a silicon-based cover element and a non-metal base plate. The cover element may include a recess configured to receive one or more light-emitting devices therein. The cover element may further include one or more openings such that at least a portion of a light-emitting surface of each of the one or more light-emitting devices is exposed when the one or more light-emitting devices are received in the one or more recesses of the cover element. The one or more light-emitting devices and the cover element may be disposed on the base plate with the one or more light-emitting devices sandwiched between the cover element and the base plate. A first area of the base plate may be coated with a first electrically-conductive pattern that forms a first electrode for powering the one or more light-emitting devices. A second area of the base plate may be coated with a second electrically-conductive pattern that is electrically isolated from the first electrically-conductive pattern. An area of the cover element may be coated with a third electrically-conductive pattern that is in contact with the second electrically-conductive pattern to form a second electrode together with the second electrically-conductive pattern for powering the one or more light-emitting devices when the cover element is disposed on the base plate.

In some embodiments, the base plate may include silicon, metal-core printed circuit board (PCB), ceramics, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal. The cover element may include a first primary surface and a second primary surface opposite the first primary surface thereof with the first primary surface of the cover element facing the base plate and the one or more light-emitting devices. The second primary surface of the cover element may include a plurality of grooves.

In some embodiments, the apparatus may further include the one or more light-emitting devices, an IC device, and a silicon-based heat sink. The one or more light-emitting devices may be received in the recess of the cover element. The one or more light-emitting devices may be disposed between the base plate and the cover element and configured to receive electrical power from the first electrode and the second electrode to emit light. The one or more light-emitting devices may include one or more VCSEL or one or more LED. The IC device may be disposed on the base plate and configured to receive electrical power from the first electrode and the second electrode to control operations of the one or more light-emitting devices. The heat sink may be disposed on the IC device. The heat sink may include a first primary surface and a second primary surface opposite the first primary surface thereof with the first primary surface of the heat sink facing the IC device. The second primary surface of the heat sink may include a plurality of grooves.

According to yet another aspect, an apparatus may include one or more light-emitting devices, a base plate, a cover element, a layer of thermally-conductive material, an IC device, and a heat sink. The base plate may be made of an electrically-insulating and thermally-conductive material. The base plate may include a first primary surface and a second primary surface opposite to the first primary surface. The first primary surface may include a non-recessed area and a recess configured to receive the one or more light-emitting devices in the recess. At least a portion of the recess and a first portion of the non-recessed area may be contiguously coated with a first electrically-conductive pattern that forms a first electrode for powering the light-emitting diode. A second portion of the non-recessed area may be coated with a second electrically-conductive pattern that is electrically isolated from the first electrically-conductive pattern. The cover element may be made of a silicon-based material or a ceramic material. The cover element may be configured to be disposed on the base plate to hold the one or more light-emitting devices between the base plate and the cover element with at least a portion of a light-emitting surface of each of the one or more light-emitting devices exposed. The cover element may include a first primary surface and a second primary surface opposite to the first primary surface. The first primary surface of the cover element may be coated with a third electrically-conductive pattern. The third electrically-conductive pattern may be configured to be in contact with the second electrically-conductive pattern to form a second electrode for powering the light-emitting device when the cover element is disposed on the base plate with the first primary surface of the cover element facing the first primary surface of the base plate. The second primary surface of the cover element may include a plurality of first grooves. The layer of thermally-conductive material may be disposed on the non-recessed area of the base plate and configured to be in contact with the cover element when the cover element is disposed on the base plate such that the layer of thermally-conductive material functions as a thermal path to transfer thermal energy between the cover element and the base plate. The IC device may be disposed on the base plate and configured to receive electrical power from the first electrode and the second electrode to control operations of the one or more light-emitting devices. The heat sink may be made of a silicon-based material or a ceramic material. The heat sink may be disposed on the IC device. The heat sink may include a first primary surface and a second primary surface opposite the first primary surface thereof with the first primary surface of the heat sink facing the IC device. The second primary surface of the heat sink may include a plurality of second grooves.

DETAILED DESCRIPTION

Overview

The present disclosure describes embodiments of a thermal energy transfer apparatus that removes thermal energy from a light-emitting device and allows electrical power to be provided to the light-emitting device without using wire bonding. While aspects of described techniques relating to a thermal energy transfer apparatus that removes thermal energy from a light-emitting device can be implemented in any number of different applications, the disclosed embodiments are described in context of the following exemplary configurations.

FIGS. 1-9illustrate examples of thermal energy transfer apparatuses for a single light-emitting device.FIGS. 10-27illustrate examples of thermal energy transfer apparatuses for multiple light-emitting devices. More specifically,FIGS. 10-20illustrate various example designs to accommodate a multi-light-emitting-device package with single silicon cover element or quad-silicon cover elements.FIGS. 21 and 22illustrate a multi-light-emitting-device package integrated with a driver/controller and disposed on a base plate, with each light-emitting device covered by a respective silicon cover element.FIGS. 23 and 24illustrate a large scale light-emitting device package integrated with a driver/controller and disposed on a whole silicon wafer, with each light-emitting device covered by a respective silicon cover element.FIG. 25-27illustrate a wafer-level package with silicon heat sinks for a high-power multi-light-emitting-device package integrated with a driver/controller. It would be appreciated that, although various example designs that accommodate a quad-light-emitting-device package are shown inFIGS. 10-27, the principle and scope of the present disclosure also extend to designs that accommodate different numbers of light-emitting devices (e.g., two, three, five, six, eight, twelve, sixteen, and so on).

In the various designs, the light-emitting devices are connected with corresponding silicon cover elements that provide not only electrical connection to provide electrical power to the light-emitting devices but also thermal path to transfer heat away from the light-emitting devices. That is, each cover element provides a function in the context of thermal management with respect to the light-emitting devices, and may be constructed of single-crystal silicon. The high-precision etched cover element(s) and base plate in each design provide accurate alignment to allow automated mass production and assembly of the thermal energy transfer apparatuses with light-emitting devices packaged therein.

The multi-light-emitting-device packages of the various examples of the present disclosure provide an illumination source for general lighting or special-purpose high-power lighting for commercial, industrial and/or military applications. In various implementations, one or more light-emitting devices may be LED or substituted with VCSEL or other laser source to provide an illumination source for time-of-flight applications or other high-power applications.

Illustrative First Thermal Energy Transfer Apparatus

FIGS. 1 and 2illustrate an embodiment of a thermal energy transfer apparatus100that removes thermal energy from a light-emitting device120when the light-emitting device120is bonded, attached or otherwise coupled to the thermal energy transfer apparatus100. The thermal energy transfer apparatus100comprises a base plate110that has a first primary surface110aand a second primary surface110bopposite to the first primary surface110a. The base plate110is non-metal, and is thermally conductive and electrically insulating such that heat may be transferred from the light-emitting device120to the base plate110.

In at least one embodiment, the base plate110may be made of a silicon-based material. For example, the base plate110may be fabricated from a silicon wafer, such as a single-crystal silicon wafer. Accordingly, batch manufacturing of a plurality of base plates110from a single silicon wafer may be achieved using known or to-be-developed semiconductor or micro-electromechanical-system (MEMS) fabrication processes for high production volume with high yield rate. Alternatively, the base plate110may be made of a ceramic material such as, for example, aluminum nitride (AlN). Still alternatively, the base plate110may include metal-core printed circuit board (PCB), diamond, carbon-fiber, nanotubes, or thermally-conducting crystal.

The base plate110has a recess118on the first primary surface110a. The recess118is dimensioned to receive the light-emitting device120substantially snugly such that the light-emitting device120cannot be moved in a direction substantially parallel to the first primary surface110aor the second primary surface110bwhen the light-emitting device120is received in the recess118. That is, one or more dimensions of the recess118are fabricated to substantially match one or more dimensions of the light-emitting diode120in order to allow the light-emitting device120to fit snugly in the recess118when the light-emitting device120is bonded, attached or otherwise coupled to the base plate110to be received in the recess118.

For illustrative purpose, assuming the light-emitting device120has a width dimension X2, as shown inFIG. 1, preferably the bottom of the recess118has a dimension X1 that is the same as or substantially the same as X2 within an acceptable range of tolerance.

Moreover, the recess118has a depth Y1, as shown inFIG. 1, such that the top surface of the light emitting device120is higher than the first primary surface110awhen the bottom surface of the light-emitting device120, which is opposite to the top surface, is received in the recess118. In other words, the depth Y1 of the recess118is at least the same as or less than the height Y2 of the light-emitting device120.

In at least one embodiment, at least a portion of the first primary surface110aof the base plate110that is not recessed (hereinafter referred to as the “non-recessed area”) and at least a portion of the recess118may be contiguously coated with a first electrically-conductive pattern114athat forms a first electrode, e.g., anode, for powering the light-emitting device120. That is, the portion of the first electrically-conductive pattern114athat is disposed on the recess118and the portion of the first electrically-conductive pattern114athat is disposed on the non-recessed area of the first primary surface110aare contiguous and hence electrically coupled together. When the light-emitting device120is received in the recess118, the light-emitting device120contacts, and hence is electrically coupled to, the first electrically-conductive pattern114a.

In at least one embodiment, at least a portion of the recess118that is covered by the light-emitting device120when the light-emitting device120is received in the recess118may be coated with a layer of thermally-conductive material112. During operation, the layer of thermally-conductive material112aids the transfer of thermal energy, or heat, from the light-emitting device120to the base plate110by conduction to dissipate at least some of the heat generated by the light-emitting device120. This tends to enhance the performance as well as longevity of the light-emitting device120. In at least one embodiment, the layer of thermally-conductive material112may comprise diamond. In another embodiment, the layer of thermally-conductive material112may comprise copper, tin or silver. Alternatively, the layer of thermally-conductive material112may comprise carbon nanotubes.

In at least one embodiment, the non-recessed area of the first primary surface110aof the base plate110and at least a portion of the layer of thermally-conductive material112may be contiguously coated with the first electrically-conductive pattern114asuch that the light-emitting device120contacts, and hence is electrically coupled to, the first electrically-conductive pattern114awhen the light-emitting device112is received in the recess118of the base plate110.

Moreover, at least another portion of the first primary surface110aof the base plate110that is not recessed and not coated with the first electrically-conductive pattern114ais coated with a second electrically-conductive pattern114b. The first electrically-conductive pattern114aand the second electrically-conductive pattern114bare electrically isolated from each other.

With the bottom of the recess118coated with the layer of thermally-conductive material112and the first electrically-conductive pattern114a, when the depth Y1 of the recess118is the same as, or even slightly less than the height Y2 of the light-emitting device120, the top surface of the light-emitting device120will be higher than the first primary surface110aof the base plate110when the light-emitting device120is received in the recess118.

In at least one embodiment, at least a portion of the second primary surface110bis coated with a layer of metallic material116. The layer of metallic material116allows the bonding of the base plate110to an external object, such as a heat sink which may be, for example, a substrate, a printed circuit board (PCB), a passive cooler, an active cooler, etc. In another embodiment, the second primary surface110bis configured to allow the base plate110to be mounted on, bonded to, or otherwise attached to a heat sink which may be, for example, a substrate, a PCB, a passive cooler, an active cooler, etc. This would allow heat transferred from the light-emitting device120to the base plate110to be further transferred to such a heat sink for dissipation, thus further aiding heat removal from the light-emitting device120.

Illustrative Second Thermal Energy Transfer Apparatus

FIGS. 3-6illustrate another embodiment of the thermal energy transfer apparatus100, which comprises one or more additional components than that shown inFIGS. 1 and 2, as described below.

In at least one embodiment, in addition to the base plate110, the thermal energy transfer apparatus100may further comprise a cover element130that is non-metal, and is thermally conductive and electrically insulating. The cover element130has a second primary surface130aand a first primary surface130bthat is opposite to the second primary surface130a. The cover element130further has an opening135such that a portion of the top surface, e.g., a light-emitting surface, of the light-emitting device120is exposed and another (non-exposed) portion of the top surface of the light-emitting device120is in contact with the first primary surface130bof the cover element130when the light-emitting device120is received in the recess118of the base plate110with the cover element130disposed on, mounted on, or otherwise bonded to, the base plate110to hold the light-emitting device120between the cover element130and the base plate110.

In at least one embodiment, the cover element130may be made of a silicon-based material. For example, the cover element130may be fabricated from a silicon wafer, such as a single-crystal silicon wafer. Accordingly, batch manufacturing of a plurality of cover elements130from a single silicon wafer may be achieved using known or to-be-developed semiconductor or MEMS fabrication processes for high production volume with high yield rate. Alternatively, the cover element130may be made of a ceramic material such as, for example, aluminum nitride.

In at least one embodiment, at least a portion of the first primary surface130bof the cover element130may be metalized with a metallization layer132(hereinafter interchangeably referred to as the “third electrically-conductive pattern”). The third electrically-conductive pattern132, may be in contact with the light-emitting device120and the second electrically-conductive pattern114bthat is coated on the first primary surface110aof the base plate110when the cover element130is disposed on, mounted on, or otherwise bonded to, the base plate110with the light-emitting device120disposed between the cover element130and the base plate110. The third electrically-conductive pattern132and the second electrically-conductive pattern114bform a second electrode, e.g., cathode, for powering the light-emitting device120. The third electrically-conductive pattern132is electrically isolated from the first electrically-conductive pattern114a. The cover element130may be configured such that at least a portion of the first electrically-conductive pattern114aon the non-recessed area of the first primary surface110aof the base plate110and at least a portion of the second electrically-conductive pattern114bon the non-recessed area of the first primary surface110aof the base plate110are exposed when the cover element130is disposed on, mounted on, or otherwise bonded to, the base plate110with the light-emitting device120disposed between the cover element130and the base plate110. This way, each of the exposed portions of the first and second electrodes, i.e., the exposed portion of the first electrically-conductive pattern114aand the exposed portion of the second electrically-conductive pattern114b, may receive electrical power from respective electrical contacts to power the light-emitting device120. This is because the top surface of the light-emitting device120is in contact with the third electrically-conductive pattern132on the cover element130, which is in contact with the second electrically-conductive pattern114b, while the bottom surface of the light-emitting device120is in contact with the first electrically-conductive pattern114a. Such novel and non-obvious design avoids the need of wire bonding to power the light-emitting device120, thus eliminating the complexity and costs associated with wire bonding.

In at least one embodiment, the thermal energy transfer apparatus100may further comprise a collimating element140disposed on, mounted on, or otherwise bonded to, the second primary surface130aof the cover element130. The collimating element140has a lens portion145. The lens portion145of the collimating element140collimates light125emitted from the light-emitting device120along a direction that is substantially perpendicular to the first primary surface110aof the base plate110as shown inFIGS. 4-6. In at least one embodiment, the collimating element140is made of glass. In another embodiment, the collimating element140is made of polymer. Alternatively, the collimating element140is made of quartz.

In at least one embodiment, the thermal energy transfer apparatus100may further comprise a spacer element150disposed on, mounted on, or otherwise bonded to, the collimating element140such that the collimating element140is between the spacer element150and the cover element130. The spacer element150has an opening155that accommodates at least the lens portion145of the collimating element140and allows the light125emitted from the light-emitting device120to propagate through the spacer element150. In at least one embodiment, the spacer element150is made of silicon. In another embodiment, the spacer element150is made of ceramic.

In at least one embodiment, the thermal energy transfer apparatus100may further comprise a window element160disposed on, mounted on, or otherwise bonded to, the spacer element150such that the spacer element150is between the window element160and the collimating element140. The window element160is substantially transparent.

In at least one embodiment, the thermal energy transfer apparatus100may further comprise the light-emitting device120. The light-emitting device120may be, for example, a VCSEL, a LED, or another type of semiconductor-based laser or light source.

Illustrative Third Thermal Energy Transfer Apparatus

FIGS. 7-9illustrate a thermal energy transfer apparatus200in accordance of the present disclosure.

The apparatus200may comprise a base plate210and a cover element230. Similar to the base plate110, the base plate210is thermally conductive and electrically insulating, and may be made of a silicon-based material, e.g., single-crystal silicon, or, alternatively, a ceramic material, e.g., aluminum nitride. Alternatively, the base plate210may include silicon, metal-core PCB, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal. Similar to the cover element130, the cover element230is thermally conductive and electrically insulating, and may be made of a silicon-based material, e.g., single-crystal silicon, or, alternatively, a ceramic material, e.g., aluminum nitride. Many features and functionalities of the base plate210and cover element230are similar to those of the base plate110and cover element130, respectively. Thus, in the interest of brevity, the following detailed description will be directed to features and functionalities of the base plate210and cover element230that differ from those of the base plate110and cover element130.

As shown inFIGS. 7-9, the base plate210includes a recess that is configured to receive a light-emitting device220therein for the light-emitting device220to emit a beam of photonic energy in a direction225. The recess includes a main portion that is dimensioned to receive the light-emitting device220therein snugly. The recess also includes a channel portion that is connected to the main portion. A first area of the base plate210is coated with a first electrically-conductive pattern that forms a first electrode, e.g., anode, for powering the light-emitting diode. In particular, the first electrically-conductive pattern includes a first portion214disposed in the recess, a second portion216disposed on the non-recessed area of the first primary surface of the base plate210, and a third portion215that connects the first portion214and the second portion216. In other words, the first electrically-conductive pattern is contiguously coated on, deposited on, or otherwise disposed on, the recess and the non-recessed area of the base plate210to form a first electrode, e.g., anode, for powering the light-emitting device220. A second area of a non-recessed portion of the base plate210is coated with a second electrically-conductive pattern226that is electrically isolated from the first electrically-conductive pattern.

The cover element230is configured to be disposed on the base plate210to hold the light-emitting device220between the base plate210and the cover element230with at least a portion of a light-emitting surface of the light-emitting device220exposed. An area of the cover element230facing the base plate210is coated with a third electrically-conductive pattern232to be in contact with the second electrically-conductive pattern226to form a second electrode, e.g., cathode, together with the second electrically-conductive pattern226for powering the light-emitting device220when the cover element230is disposed on the base plate210. The cover element230is not in contact with the first electrically-conductive pattern, e.g., the second portion216, when the cover element230is disposed on the base plate210. More specifically, either or both of the cover plate230and the channel portion of the recess on the base plate210may be dimensioned such that there exists a gap217between the cover element230and the second portion216of the first electrically-conductive pattern. This feature ensures that there is no contact between the third electrically-conductive pattern232and the second portion216of the first electrically-conductive pattern that would result in a short circuit.

In at least one embodiment, the thermal energy transfer apparatus200may further comprise a collimating element140as described above with respect to the apparatus100.

In at least one embodiment, the thermal energy transfer apparatus200may further comprise a spacer element150as described above with respect to the apparatus100.

In at least one embodiment, the thermal energy transfer apparatus200may further comprise a window element160as described above with respect to the apparatus100.

In at least one embodiment, the thermal energy transfer apparatus200may further comprise the light-emitting device220. The light-emitting device220may be, for example, a VCSEL, a LED, or another type of semiconductor-based laser or light source.

Illustrative Fourth Thermal Energy Transfer Apparatus

FIGS. 10-12illustrate a thermal energy transfer apparatus1001for one or more light-emitting devices in accordance with yet another embodiment of the present disclosure.

As shown inFIGS. 10-12, apparatus1001includes a base plate302and a cove element301, both of which are non-metal. In some embodiments, base plate302may be silicon-based and made of single-crystal silicon. Alternatively, base plate302may be made of ceramic or another suitable non-metal material. For example, base plate302may include metal-core PCB, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal. In some embodiments, cover element301may be silicon-based and made of single-crystal silicon. Alternatively, cover element301may be made of ceramic or another suitable non-metal material. While similar to apparatus100and apparatus200in certain aspects, apparatus1001is scaled up to accommodate one or more light-emitting devices. In the illustrated example, apparatus1001is configured to accommodate four light-emitting devices300a,300b,300cand300d.

The base plate302may include a recess configured to receive one or more light-emitting devices therein. As shown inFIGS. 10-12, the recess is configured to receive the light-emitting devices300a,300b,300cand300d. A first area of the base plate302may be coated with a first electrically-conductive pattern304that forms a first electrode307, e.g., anode electrode, for powering the one or more light-emitting devices. A second area of the base plate302may be coated with a second electrically-conductive pattern305that is electrically isolated from the first electrically-conductive pattern304. The cover element301may be configured to be disposed on the base plate302to hold the one or more light-emitting devices (e.g., light-emitting devices300a,300b,300cand300d) between the base plate302and the cover element301with at least a portion of a light-emitting surface of each of the one or more light-emitting devices exposed (e.g., the upward-facing surface of light-emitting devices300a,300b,300cand300das shown inFIGS. 10-12). An area of the cover element302may be coated with a third electrically-conductive pattern306that is in contact with the second electrically-conductive305pattern to form a second electrode, e.g., cathode electrode, together with the second electrically-conductive pattern305for powering the one or more light-emitting devices when the cover element302is disposed on the base plate301.

One side (e.g., the upward-facing side as shown inFIGS. 10-12) of each of the light-emitting devices300a,300b,300cand300dis electrically connected by the second electrode (formed by the second electrically-conductive pattern305and the third electrically-conductive pattern306) while the opposite side (e.g., the downward-facing side as shown inFIGS. 10-12) of each of the light-emitting devices300a,300b,300cand300dis electrically connected to the first electrode307(formed by the second-electrically conductive pattern304). The first electrode307and the second electrode are electrically isolated from each other.

In some embodiments, the cover element301may have a first primary surface (e.g., the downward-facing surface as shown inFIGS. 10-12) and a second primary surface (e.g., the upward-facing surface as shown inFIGS. 10-12) opposite the first primary surface thereof with the first primary surface of the cover element301facing the base plate302and the one or more light-emitting devices. The second primary surface of the cover element301may include a plurality of grooves.

In some embodiments, the base plate302may include a first primary surface (e.g., the upward-facing surface as shown inFIGS. 10-12) and a second primary surface (e.g., the downward-facing surface as shown inFIGS. 10-12) opposite to the first primary surface. The first primary surface of the base plate302may include a non-recessed area and the recess. The recess is configured to receive the one or more light-emitting devices therein. At least a portion of the recess and a first portion of the non-recessed area of the base plate302are contiguously coated with the first electrically-conductive pattern304. A second portion of the non-recessed area of the base plate302is coated with the second electrically-conductive pattern305. The cover element301may include a first primary surface (e.g., the downward-facing surface as shown inFIGS. 10-12) and a second primary surface (e.g., the upward-facing surface as shown inFIGS. 10-12) opposite to the first primary surface. The first primary surface of the cover element301may be coated with the third electrically-conductive pattern306that is configured to be in contact with the second electrically-conductive pattern305when the cover element301is disposed on the base plate302with the first primary surface of the cover element301facing the first primary surface of the base plate302.

In some embodiments, the recess may include a main portion and a channel portion with the main portion dimensioned to receive the one or more light-emitting devices therein. A first part of the first electrically-conductive pattern304may be disposed in the main portion and the channel portion of the recess. A second part of the first electrically-conductive pattern304that is contiguous with the first part of the first electrically-conductive pattern304may be disposed on the first portion of the non-recessed area of the first primary surface of the base plate302. The cover element301may be configured to be not in contact with the second part of the first electrically-conductive pattern304when the cover element301is disposed on the base plate302.

In some embodiments, apparatus1001may further include a layer of thermally-conductive material308disposed on a non-recessed area of the base plate302and configured to be in contact with the cover element301when the cover element301is disposed on the base plate302such that the layer of thermally-conductive material308functions as a thermal path to transfer thermal energy between the cover element301and the base plate302. For example, the layer of thermally-conductive material308may be a metal pad and allows flowing of heat between the cover element301and the base plate302after absorbing the heat from light-emitting devices300a,300b,300cand300d.

In some embodiments, the layer of thermally-conductive material308may include diamond, copper, tin, silver or carbon nanotubes.

In some embodiments, apparatus1001may further include a layer of metallic material (not shown) disposed on at least a portion of the second primary surface of the base plate302, similar to the layer of metallic material116of apparatus100. The metallic material may bond the base plate302to an external object.

In some embodiments, apparatus1001may further include a collimating element (not shown) disposed on the cover element301, similar to the collimating element140of apparatus100and apparatus200. The collimating element may include a lens portion that collimates light emitted from the one or more light-emitting devices along a predefined direction.

In some embodiments, the collimating element may be made of glass, polymer, or quartz.

In some embodiments, apparatus1001may further include a spacer element (not shown) disposed on the collimating element with the collimating element disposed between the spacer element and the cover element301, similar to the collimating element140of apparatus100and apparatus200. The spacer element may include an opening that accommodates at least the lens portion of the collimating element and may allow the light emitted from the one or more light-emitting devices to propagate through the spacer element.

In some embodiments, the spacer element may be made of silicon or ceramic.

In some embodiments, apparatus1001may further include a window element (not shown) disposed on the spacer element with the spacer element disposed between the window element and the collimating element, similar to the window element160of apparatus100and apparatus200. The window element may be substantially transparent.

In some embodiments, apparatus1001may further include the one or more light-emitting devices, e.g., the light-emitting devices300a,300b,300cand300d, received in the recess of the base plate302. The one or more light-emitting devices may be disposed between the base plate302and the cover element301and configured to receive electrical power from the first electrode307and the second electrode to emit light. The one or more light-emitting devices may include one or more vertical-cavity surface-emitting laser (VCSEL) or one or more light-emitting diodes (LED).

It is noteworthy that, although the example apparatus1001shown inFIGS. 10-12has the recess on the base plate302, in alternative embodiments, it is the cover element301that has a recess configured to receive the one or more light-emitting devices therein. The recess, whether a feature on the base plate302or a feature on the cover element301, allows passive alignment of the one or more light-emitting devices in a mass production setting in which light-emitting devices such as light-emitting devices300a,300b,300cand300dmay simply be placed in the recess to be aligned with respect the entire package of apparatus1001.

Illustrative Fifth Thermal Energy Transfer Apparatus

FIGS. 13-15illustrate a thermal energy transfer apparatus1002for one or more light-emitting devices in accordance with still another embodiment of the present disclosure. Certain features of apparatus1002are similar to corresponding features of apparatus1001while certain other features of apparatus1002differ from respective features of apparatus1001. Thus, in the interest of brevity, the detailed description of apparatus1002below is focused on the differences between apparatus1002and apparatus1001.

Apparatus1002includes a base plate357, which is non-metal. In some embodiments, base plate357may be silicon-based and made of single-crystal silicon. Alternatively, base plate357may be made of ceramic or another suitable non-metal material. For example, base plate357may include metal-core PCB, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal. As shown inFIGS. 13-15, rather than a single piece of cover element, apparatus1002comprises multiple cover elements351,352,353and354. The cover elements351,352,353and354may be non-metal. In some embodiments, at least one of the cover elements351,352,353and354may be silicon-based and made of single-crystal silicon. Alternatively, at least one of the cover elements351,352,353and354may be made of ceramic or another suitable non-metal material.

The base plate357may include a recess configured to receive one or more light-emitting devices therein. As shown inFIGS. 13-15, the recess is configured to receive the light-emitting devices350a,350b,350cand350d. A first area of the base plate357may be coated with a first electrically-conductive pattern355that forms a first electrode359, e.g., anode electrode, for powering the one or more light-emitting devices. A second area of the base plate357may be coated with a second electrically-conductive pattern356that is electrically isolated from the first electrically-conductive pattern355. Each of the cover elements351,352,353and354may be configured to be disposed on the base plate357to hold the one or more light-emitting devices (e.g., light-emitting devices350a,350b,350cand350d) between the base plate357and the cover elements351,352,353and354with at least a portion of a light-emitting surface of each of the one or more light-emitting devices exposed (e.g., the upward-facing surface of light-emitting devices350a,350b,350cand350das shown inFIGS. 13-15). An area of each of the cover elements351,352,353and354may be coated with a third electrically-conductive pattern358a,358b,358cand358d, respectively, which is in contact with the second electrically-conductive356pattern to form a second electrode, e.g., cathode electrode, together with the second electrically-conductive pattern356for powering the one or more light-emitting devices when the cover elements351,352,353and354are disposed on the base plate357.

One side (e.g., the upward-facing side as shown inFIGS. 13-15) of each of the light-emitting devices350a,350b,350cand350dis electrically connected by the second electrode (formed by the second electrically-conductive pattern356and the third electrically-conductive pattern358a,358b,358cand358d) while the opposite side (e.g., the downward-facing side as shown inFIGS. 13-15) of each of the light-emitting devices350a,350b,350cand350dis electrically connected to the first electrode359(formed by the second-electrically conductive pattern355). The first electrode359and the second electrode are electrically isolated from each other.

In some embodiments, each of the cover elements351,352,353and354may have a first primary surface (e.g., the downward-facing surface as shown inFIGS. 13-15) and a second primary surface (e.g., the upward-facing surface as shown inFIGS. 13-15) opposite the first primary surface thereof with the first primary surface of each of the cover elements351,352,353and354facing the base plate357and the one or more light-emitting devices. The second primary surface of each of the cover elements351,352,353and354may include a plurality of grooves.

In some embodiments, the base plate357may include a first primary surface (e.g., the upward-facing surface as shown inFIGS. 13-15) and a second primary surface (e.g., the downward-facing surface as shown inFIGS. 13-15) opposite to the first primary surface. The first primary surface of the base plate357may include a non-recessed area and the recess. The recess is configured to receive the one or more light-emitting devices therein. At least a portion of the recess and a first portion of the non-recessed area of the base plate357are contiguously coated with the first electrically-conductive pattern355. A second portion of the non-recessed area of the base plate357is coated with the second electrically-conductive pattern356. The first primary surface of each of the cover elements351,352,353and354may be coated with the third electrically-conductive pattern358a,358b,358cand358dthat is configured to be in contact with the second electrically-conductive pattern356when any of the cover elements351,352,353and354is disposed on the base plate357with the first primary surface of the respective cover element facing the first primary surface of the base plate357.

In some embodiments, the recess may include a main portion and a channel portion with the main portion dimensioned to receive the one or more light-emitting devices therein. A first part of the first electrically-conductive pattern355may be disposed in the main portion and the channel portion of the recess. A second part of the first electrically-conductive pattern355that is contiguous with the first part of the first electrically-conductive pattern355may be disposed on the first portion of the non-recessed area of the first primary surface of the base plate357. At least one of the cover elements351,352,353and354may be configured to be not in contact with the second part of the first electrically-conductive pattern355when the respective cover element is disposed on the base plate357.

In some embodiments, apparatus1002may further include the one or more light-emitting devices, e.g., the light-emitting devices350a,350b,350cand350d, received in the recess of the base plate357. The one or more light-emitting devices may be disposed between the base plate357and the cover elements351,352,353and354, and receive electrical power from the first electrode359and the second electrode to emit light. The one or more light-emitting devices may include one or more VCSEL or one or more LED.

Thus, in apparatus1002, the cover elements351,352,353and354are electrically connected with the first electrode359for supplying power to light-emitting devices350a,350b,350cand350d. The second electrode may bond the light-emitting devices350a,350b,350cand350dto the base plate357by metal solder.

Illustrative Sixth Thermal Energy Transfer Apparatus

FIGS. 16-20illustrate a thermal energy transfer apparatus1003for one or more light-emitting devices in accordance with yet another embodiment of the present disclosure.

As shown inFIGS. 16-18, apparatus1003includes a base plate402and a cove element401, both of which are non-metal. In some embodiments, base plate402may be silicon-based and made of single-crystal silicon. Alternatively, base plate402may be made of ceramic or another suitable non-metal material. For example, base plate402may include metal-core PCB, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal. In some embodiments, cover element401may be silicon-based and made of single-crystal silicon. Alternatively, cover element401may be made of ceramic or another suitable non-metal material. While similar to apparatus100and apparatus200in certain aspects, apparatus1003is scaled up to accommodate one or more light-emitting devices. In the illustrated example, apparatus1003is configured to accommodate four light-emitting devices400a,400b,400cand400d.

As shown inFIGS. 19 and 20, the cover element401may include a recess412a,412b,412cand412deach of which configured to receive a respective light-emitting devices therein. The cover element401may also include one or more openings411a,411b,411cand411dto expose at least a portion of a light-emitting surface of the light-emitting devices400a,400b,400cand400dwhen the light-emitting devices400a,400b,400cand400dare disposed between the cover element401and the base plate402. The one or more light-emitting devices and the cover element401may be disposed on the base plate402with the one or more light-emitting devices sandwiched between the cover element401and the base plate402.

A first area of the base plate402may be coated with a first electrically-conductive pattern404that forms a first electrode408, e.g., anode electrode, for powering the one or more light-emitting devices. A second area of the base plate402may be coated with a second electrically-conductive pattern405that is electrically isolated from the first electrically-conductive pattern404. The cover element401may be configured to be disposed on the base plate402to hold the one or more light-emitting devices (e.g., light-emitting devices400a,400b,400cand400d) between the base plate402and the cover element401with at least a portion of a light-emitting surface of each of the one or more light-emitting devices exposed (e.g., the upward-facing surface of light-emitting devices400a,400b,400cand400das shown inFIGS. 16-18). An area of the cover element402may be coated with a third electrically-conductive pattern407that is in contact with the second electrically-conductive405pattern to form a second electrode, e.g., cathode electrode, together with the second electrically-conductive pattern405for powering the one or more light-emitting devices when the cover element402is disposed on the base plate401.

One side (e.g., the upward-facing side as shown inFIGS. 16-18) of each of the light-emitting devices400a,400b,400cand400dis electrically connected by the second electrode (formed by the second electrically-conductive pattern405and the third electrically-conductive pattern407) while the opposite side (e.g., the downward-facing side as shown inFIGS. 16-18) of each of the light-emitting devices400a,400b,400cand400dis electrically connected to the first electrode408(formed by the second-electrically conductive pattern404). The first electrode408and the second electrode are electrically isolated from each other.

In some embodiments, the cover element401may have a first primary surface (e.g., the downward-facing surface as shown inFIGS. 16-18) and a second primary surface (e.g., the upward-facing surface as shown inFIGS. 16-18) opposite the first primary surface thereof with the first primary surface of the cover element401facing the base plate402and the one or more light-emitting devices. The second primary surface of the cover element401may include a plurality of grooves.

In some embodiments, apparatus1003may further include a shim element406disposed between the base plate402and the cover element401to accommodate the thickness or height of the one or more light-emitting devices. For example, a thickness or height of the shim element406plus a depth of the recess in the cover element401may be approximately equal to the thickness or height of the one or more light-emitting devices.

In some embodiments, apparatus1003may further include a layer of metallic material (not shown) disposed on at least a portion of the second primary surface of the base plate402, similar to the layer of metallic material116of apparatus100. The metallic material may bond the base plate402to an external object.

In some embodiments, apparatus1003may further include a collimating element (not shown) disposed on the cover element401, similar to the collimating element140of apparatus100and apparatus200. The collimating element may include a lens portion that collimates light emitted from the one or more light-emitting devices along a predefined direction.

In some embodiments, the collimating element may be made of glass, polymer, or quartz.

In some embodiments, apparatus1003may further include a spacer element (not shown) disposed on the collimating element with the collimating element disposed between the spacer element and the cover element401, similar to the collimating element140of apparatus100and apparatus200. The spacer element may include an opening that accommodates at least the lens portion of the collimating element and may allow the light emitted from the one or more light-emitting devices to propagate through the spacer element.

In some embodiments, the spacer element may be made of silicon or ceramic.

In some embodiments, apparatus1003may further include a window element (not shown) disposed on the spacer element with the spacer element disposed between the window element and the collimating element, similar to the window element160of apparatus100and apparatus200. The window element may be substantially transparent.

In some embodiments, apparatus1003may further include the one or more light-emitting devices, e.g., the light-emitting devices400a,400b,400cand400d, received in the recess of the base plate402. The one or more light-emitting devices may be disposed between the base plate402and the cover element401and configured to receive electrical power from the first electrode408and the second electrode to emit light. The one or more light-emitting devices may include one or more VCEL or one or more LED.

It is noteworthy that, although the example apparatus1003shown inFIGS. 16-18has the recess on the base plate402, in alternative embodiments, it is the cover element401that has a recess configured to receive the one or more light-emitting devices therein. The recess, whether a feature on the base plate402or a feature on the cover element401, allows passive alignment of the one or more light-emitting devices in a mass production setting in which light-emitting devices such as light-emitting devices400a,400b,400cand400dmay simply be placed in the recess to be aligned with respect the entire package of apparatus1003.

A unique feature in the design of apparatus1003is that cover element is electrically connected to the one or more light-emitting devices without any wire-bonding, and this improves thermal management. In this design, the light-emitting devices400a,400b,400cand400dare registered into the recess of the patterned cover element401. The second electrode is soldered to the light-emitting devices400a,400b,400cand400dand the patterned silicon cover (401). The first electrode408is soldered to the light-emitting devices400a,400b,400cand400dand the base plate402. The shim element406is also soldered between the cover element401and the base plate402. The shim element406is configured to transfer thermal energy between the cover element401and the base plate402. The shim element406is preferably a highly thermal conductive material such as, for example, copper, silver, crystal, silicon, diamond, carbon fiber, or carbon nanotubes. Alternatively, the shim element406may include SiO2, SiN, or AlN.

Illustrative Seventh Thermal Energy Transfer Apparatus

FIGS. 21 and 22illustrate a thermal energy transfer apparatus1004for one or more light-emitting devices in accordance with an embodiment of the present disclosure.

As shown inFIGS. 21 and 22, apparatus1004includes a non-metal base plate455and multiple non-metal cover elements451,452,453and454. In some embodiments, base plate455may be silicon-based and made of single-crystal silicon. Alternatively, base plate455may be made of ceramic or another suitable non-metal material. For example, base plate455may include metal-core PCB, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal. In some embodiments, at least one of the cover elements451,452,453and454may be silicon-based and made of single-crystal silicon. Alternatively, at least one of the cover elements451,452,453and454may be made of ceramic or another suitable non-metal material. As certain features of apparatus1004are similar to those of apparatus1002, in the interest of brevity the description of apparatus1004is focused on features of apparatus1004different from those of apparatus1002.

Similar to apparatus1002, the base plate455and the cover elements451,452,453and454have electrically-conductive patterns thereon to supply power to one or more light-emitting devices (e.g., light-emitting devices450a,450b,450cand450d) when the light-emitting devices are disposed between the base plate455and the cover elements451,452,453and454. One of such electrically-conductive patterns, electrically-conductive pattern458, is shown inFIGS. 21 and 22. The electrically-conductive patterns are electrically connected to electrical pads456or457, respectively, to form first and second electrodes and function as the cathode or anode.

In some embodiments, apparatus1004may further include the one or more light-emitting devices received in the recess of the cover elements451,452,453and454. The one or more light-emitting devices are disposed between the base plate455and the cover elements451,452,453and454, and receive electrical power from the electrodes to emit light. The one or more light-emitting devices may include one or more VCSEL or one or more LED.

In some embodiments, apparatus1004may further include an IC device459which is disposed on the base plate455and configured to receive electrical power from the electrodes to control operations of the one or more light-emitting devices450a,450b,450cand450d. The IC device459may be, for example, a power driver.

In apparatus1004, having the IC device459and the light-emitting devices450a,450b,450cand450dmounted on the base plate455in close proximity (i.e., short distance therebetween) allows a fast signal switching on the light-emitting devices450a,450b,450cand450dfor high peak power operation.

Illustrative Eighth Thermal Energy Transfer Apparatus

FIGS. 23 and 24illustrate a thermal energy transfer apparatus1005for one or more light-emitting devices in accordance with another embodiment of the present disclosure.

As shown inFIGS. 23 and 24, apparatus1005includes a non-metal base plate509and multiple non-metal cover elements501,502,503,504,505,506,507and508. In some embodiments, base plate509may be silicon-based and made of single-crystal silicon. In some embodiments, at least one of the cover elements501,502,503,504,505,506,507and508may be silicon-based and made of single-crystal silicon. Alternatively, at least one of the cover elements501,502,503,504,505,506,507and508may be made of ceramic or another suitable non-metal material. As certain features of apparatus1005are similar to those of apparatus1004, in the interest of brevity the description of apparatus1005is focused on features of apparatus1005different from those of apparatus1004.

Similar to apparatus1004, the base plate509and the cover elements501,502,503,504,505,506,507and508have electrically-conductive patterns thereon (including, for example, electrical traces513and563) to supply power to one or more light-emitting devices (e.g., light-emitting devices500a,500b,500c,500d,500e,500f,500gand500h) when the light-emitting devices are disposed between the base plate509and the cover elements501,502,503,504,505,506,507and508. The electrically-conductive patterns are electrically connected to electrical pads510or511, respectively, to form first and second electrodes and function as the cathode or anode.

In some embodiments, apparatus1005may further include the one or more light-emitting devices received in a recess of the base plate509or in a recess of the cover elements501,502,503,504,505,506,507and508. The one or more light-emitting devices are disposed between the base plate509and the cover elements501,502,503,504,505,506,507and508, and receive electrical power from the electrodes to emit light. The one or more light-emitting devices may include one or more VCSEL or one or more LED.

In some embodiments, apparatus1005may further include an IC device512which is disposed on the base plate509and configured to receive electrical power from the electrodes to control operations of the one or more light-emitting devices500a,500b,500c,500d,500e,500f,500gand500h. The IC device509may be, for example, a power driver.

The base plate509may be made with a single-crystal silicon for a high power illumination source. A whole single-crystal silicon wafer may be etched or patterned to make the base plate509suitable for several hundred watts of lighting power used in various industrial application such as warehouse lighting, street lighting, airport area, night-event sport area, shipyard and so on. One advantage of wafer level assembly is that the need for touch-labor is reduced to lower the manufacturing cost of the high-power lighting device encompassing apparatus1005. Due to the high-precision silicon part, automation of the production of the high-power lighting device, which encompasses apparatus1005, may be implemented relatively easily.

Illustrative Ninth Thermal Energy Transfer Apparatus

FIGS. 25-27illustrate a thermal energy transfer apparatus1006for one or more light-emitting devices in accordance with yet another embodiment of the present disclosure.

As shown inFIGS. 25-27, apparatus1006includes a non-metal base plate552and non-metal cover element551. In some embodiments, base plate552may include silicon, metal-core PCB, ceramics, diamond, carbon-fiber, nanotubes, or thermally-conducting crystal. In some embodiments, the cover element551may be silicon-based and made of single-crystal silicon. Alternatively, the cover element551may be made of ceramic or another suitable non-metal material. As certain features of apparatus1006are similar to those of apparatus1005, in the interest of brevity the description of apparatus1006is focused on features of apparatus1005different from those of apparatus1005.

Similar to apparatus1005, the base plate552and the cover element551have electrically-conductive patterns thereon to supply power to one or more light-emitting devices (e.g., light-emitting devices550a,550b,550c,550d,550e,550f,550gand550h) when the light-emitting devices are disposed between the base plate552and the cover element551. The electrically-conductive patterns are electrically connected to electrical pads557or558, respectively, to form first and second electrodes and function as the cathode or anode.

In some embodiments, apparatus1006may further include the one or more light-emitting devices received in a recess of the base plate552or in a recess of the cover element551. The one or more light-emitting devices are disposed between the base plate552and the cover element551, and receive electrical power from the electrodes to emit light. The one or more light-emitting devices may include one or more VCSEL or one or more LED.

In some embodiments, apparatus1006may further include an IC device553which is disposed on the base plate552and configured to receive electrical power from the electrodes to control operations of the one or more light-emitting devices550a,550b,550c,550d,550e,550f,550gand550h. The IC device553may be, for example, a power driver.

In some embodiments, apparatus1006may further include a silicon-based heat sink554disposed on the IC device553. The heat sink554may include a first primary surface and a second primary surface opposite the first primary surface thereof with the first primary surface of the heat sink facing the IC device553. The second primary surface of the heat sink554may include a plurality of grooves to promote dissipation of thermal energy to the ambience via at least convection.

Compared to apparatus1005, instead of having multiple cover elements (e.g.,501,502. . .508), apparatus1006has a single silicon element551bonded with multiple light-emitting devices (e.g., light-emitting devices550a,550b,550c,550d,550e,550f,550gand550h) as shown inFIG. 25-27. Bonding all the light-emitting devices550a,550b. . .550hwith the cover element551simplifies the assembly process. The cover element551may be also bonded to a first heat sink555that is made of a single-crystal silicon and having a plurality of grooves for better heat transfer to the ambience via at least convection. Also, the base plate552may be mounted on a second heat sink556that is also made with a single-crystal silicon. Due to the large size of the high-power IC device553, the separate heat sink554is mounted on the top of the IC device553. Depending on the size of IC device553, it can be also mounted on or integrated in the base plate552or the cover element551. The first heat sink555may have a plurality of grooves thereon to promote dissipation of thermal energy to the ambience via at least convection. Similarly, the second heat sink556may have a plurality of grooves thereon to promote dissipation of thermal energy to the ambience via at least convection.

As shown inFIG. 27, the wafer-level assembly of the light-emitting devices550a,550b. . .550hmay be applied to any silicon wafer size and shape to build a light fixture for illumination application. The light fixture may be built for a few watts of light power to a several hundred watts or larger.

ADDITIONAL NOTES

The above-described techniques pertain to silicon-based thermal energy transfer apparatus, or cooling packages, for light-emitting devices. The novel thermal energy transfer apparatus advantageously removes thermal energy from one or more light-emitting devices and allows electrical power to be provided to the light-emitting device without using wire bonding.

Although the techniques have been described in language specific to structural features and/or methodological acts, it is to be understood that the appended claims are not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing such techniques. Furthermore, although the techniques have been illustrated in the context of cooling package for a VCSEL, the techniques may be applied in any other suitable context such as, for example, cooling package for LED.