Thermal management in laser diode device

Laser diodes can be used in a variety of environments. Some of them involve switching the laser diode on and off in rapid succession. For example, a depth camera is pulsed at high frequencies to measure depth based on how long it takes for light to be reflected off an object and return to the camera. One or more laser diodes may be utilized. However, such high frequency vibrations can lead to inductive losses. In addition, laser diodes and associated driver circuits can dissipate significant amounts of heat during such use.

<p num="0002"> Embodiments relating to inductive loss mitigation and thermal management in optical assemblies including laser diodes are disclosed. For example, one disclosed embodiment provides an optical assembly that includes a printed circuit board and a laser diode package and laser diode driver that are attached to the printed circuit board. In addition, the heat sink is coupled to the laser diode driver to provide a first heat path that conducts heat from the laser diode driver. In addition, the coupler is coupled to the laser diode package and printed circuit board to provide a second different heat path that conducts heat from the laser diode package.</p><p num="0003"> This overview is provided to present in a simplified form a set of ideas further described below in the form for carrying out the invention. This overview is not intended to identify key or essential functions of the subject being claimed and is not intended to be used to limit the scope of the subject being claimed. Moreover, the subject matter claimed is not limited to the practice of resolving any disadvantages noted in any part of this disclosure.</p>

<figref num="1">It is a figure which shows the exemplary optical device according to the embodiment of this disclosure.</figref>

<figref num="2">It is a front view which shows the printed circuit board of the optical assembly according to the embodiment of this disclosure.</figref>

<figref num="3">It is a back view which shows the printed circuit board of FIG. 2 according to the embodiment of this disclosure.</figref>

<figref num="4">It is a perspective view which shows the laser diode and the laser diode package of FIG. 2 according to the embodiment of this disclosure.</figref>

<figref num="5">FIG. 5 is a cross-sectional view showing an optical assembly according to an embodiment of the present disclosure.</figref>

<figref num="6">It is a flowchart which shows the method of manufacturing the optical assembly according to the embodiment of this disclosure.</figref>

<figref num="7">FIG. 6 is a block diagram showing an exemplary computer system according to an embodiment of the present disclosure.</figref>

As mentioned above, the high frequency vibration of the laser diode can cause inductive losses and can also generate significant heat. Induced loss can be reduced by reducing the distance between the driver circuit and the laser diode. However, since both the heat from the laser diode and the heat from the driver circuit are dissipated in a relatively small volume of space, reducing that distance can result in higher operating temperatures.

Thus, embodiments relating to reducing inductive losses while controlling heat dissipation in optical assemblies that include laser diodes are disclosed. For example, in some embodiments, the optical assembly is positioned on the opposite side of the printed circuit board to the laser diode driver so that the current from the driver travels by the thickness of the printed circuit board to reach the laser diode. It may include a diode package. In addition, the laser diode package is coupled to the coupler, which separates the heat dissipated by the laser diode in the path around the edge of the printed circuit board from where the heat sink receives heat from the laser diode driver. Conducts to the upper place. Therefore, the heat from the laser diode package dissipates differently from the heat from the laser diode driver, even with a laser diode driver placed in close proximity to the laser diode package to achieve the desired low inductance. Can substantially follow the heat path of.

The use of separate heat paths to dissipate heat from laser diodes and driver circuits mounted on both sides of the circuit board is compared to optical assemblies that have heat paths and / or coupled heat paths that are located close to each other. It can provide increased thermal efficiency while maintaining low thermal resistance to the heat sink. In addition, the proximity of the laser diode driver to the leads of the laser diode package can result in lower inductance for high speed signal transmission and control compared to optical assemblies with the laser diode driver separated from the laser diode package. The configuration may provide additional EMI shielding and may allow the removal of thermoelectric coolers in thermal solutions to increase cost effectiveness compared to other configurations. In addition, the optical assembly may include elements that help attach the laser diode package, laser diode driver, coupler, and heat sink to the printed circuit board and / or attach them to each other. Thus, the optical assembly may allow for optical mechanical pointing and may increase placement accuracy compared to other configurations that omit such elements.

FIG. 1 shows an exemplary usage environment 100 for an embodiment of an optical device 102 in the form of a depth camera 104. As mentioned above, the depth camera projects a high frequency pulse of light into the environment through one or more laser diodes so that the pulse returns so that the depth can be determined from the return time. Measure the time required for. It will be appreciated that some depth cameras may utilize technologies other than so-called "time-of-flight" depth sensing. For example, some cameras project a structural light pattern (eg, through diffraction of light from a laser diode) and then depth from the distortion of the structural light pattern when received by an image sensor. Can be measured. Although described here in the context of depth cameras, it will be appreciated that optical devices that utilize laser diodes can be used in any system. Examples include, but are not limited to, telecommunications, measuring instruments, scanning devices, monitoring devices, reading devices, and the like.

As shown in the usage environment 100 of FIG. 1, the depth camera 104 can be operationally connected to the computer device 106 (computing device). Although the computer device 106 is shown in Figure 1 as a video game console, it will be appreciated that the optical device can be operationally connected to any other suitable computer device. Examples include, but are not limited to, personal computers, mobile computing devices, smartphones, tablet computers, and the like.

The computer device 106 may also be operationally connected to the display device 108. The computer device 106 may provide a signal to the display device 108 to display visible content such as video game content and / or other content on the display 110. Thus, user 112 (user) may provide input to computer device 106 via gestures, postures, face recognition, and / or other inputs detectable through the depth camera 104, such Inputs can be used to control the display of content on display 110.

The depth camera 104 may include an optical assembly that provides one or more of the functionality described above. FIG. 2 shows an embodiment of an optical assembly 200 including a printed circuit board 202 (PCB). FIG. 2 shows the front side (front) or front of the printed circuit board 202, where the term "front" refers to the side on which one or more laser diodes are located. The optical assembly 200 further includes a plurality of couplers 204 mounted on the printed circuit board 202, each coupler 204 thermally coupling a laser diode to a heat sink located on the rear side (rear surface) of the printed circuit board 202. .. Each coupler 204 includes an opening 206 and a laser diode package is placed within the opening 206 as described in detail with reference to FIG. Aperture 206 provides an outlet for the light emitted by the laser diode package to exit the optical assembly.

As shown in FIG. 2, the coupler 204 is mounted relatively close to each other and adjacent to each other in front of the printed circuit board 202. In other embodiments, the coupler 204 may be attached to the printed circuit board in any other suitable arrangement. The coupler 204 may be attached to or otherwise attached to the printed circuit board by any suitable mechanism or combination of mechanisms, such as adhesives, mechanical connectors, pressure fit / friction fit, and the like.

FIG. 3 shows a laser diode driver 302 mounted on the back surface of a printed circuit board 202 according to an embodiment of the present disclosure. FIG. 3 also shows a coupler 204 extending around the sides of the printed circuit board 202, where the term "side" refers to any surface of the printed circuit board that extends between the front and back of the printed circuit board 202. Shown. In an embodiment of the depiction, the coupler 204 extends around the side edge of the printed circuit board 202 by extending through a notch formed in the side edge. In other embodiments, the coupler may extend through the sides of the printed circuit board in the form of holes or openings formed within the printed circuit board. The printed circuit board 202 may include any suitable structure to which the coupler 204 fits. The printed circuit board 202 may further include holes and / or other receptacles 304 for mounting couplers 204, heat sinks, or other structures.

FIG. 4 illustrates a perspective view of an embodiment of an optical assembly 400 that includes a coupler 204 and a laser diode package 404. Although described herein as holding a laser diode package, it will be appreciated that the coupler can hold any other suitable heat generating element, such as a light emitting diode.

The laser diode package 404 is inserted into a receptacle 408 that is located within the first portion of the coupler 204, which contains an aperture that allows light to be projected from the optical assembly into the operating environment. The laser diode package 404 further includes an electrical lead 406 that electrically connects the laser diode package 404 to a laser diode driver such as the laser diode driver 302 of FIG.

The first portion 410 of the coupler 204 is configured to be separated from the printed circuit board when the coupler is mounted on the printed circuit board and is also configured to help hold the laser diode package away from the printed circuit board. Will be done. The first portion 410 may also include a fastening element 412 that clamps the coupler 204 to the printed circuit board to maintain the desired spacing between the first portion 410 of the coupler 204 and the printed circuit board. The fastening element 412 may be configured to be inserted into the receptacle 304 of FIG. 3 or otherwise secured.

The coupler 204 includes a step 415 configured such that a second portion 414 holds a first portion 410 that contacts the printed circuit board and separates it from the printed circuit board. For example, the second portion 414 is thicker than the first portion 410 and may form a step 415 due to the different thickness between the first portion 410 and the second portion 414, or the step 415. Can have any other suitable configuration to form. In an embodiment of the depiction, the second portion 414 includes a receptacle 416 and a fastener 418 that interfaces with the corresponding structure on the printed circuit board, but the coupler interfaces with any other suitable printed circuit board. It will be understood that it can also include structures.

The coupler 204 further includes a third portion 420, the third portion 420 including another step portion 422 so that the third portion 420 can extend around the sides of the printed circuit board. The step portion 422 may have any suitable configuration (eg, a configuration perpendicular to an adjacent surface, inclined with respect to an adjacent surface, etc.) and may be in contact with or separated from the side surface of the printed circuit board. You may. For example, in some embodiments, the third portion 420 is thicker than the second portion 414 and forms a stepped portion 422 due to the different thickness between the second portion 414 and the third portion 420. obtain. In other embodiments, the step structure may be formed in any other suitable manner. The third portion 420 may further include a receptacle 424 or other suitable structure that interfaces with the complementary structure on the printed circuit board. It will be appreciated again that any suitable configuration and number of receptacles, fasteners, and / or other connection structures can be provided on one or more of the elements described herein.

The stepped configuration of the coupler 204 is radiated from the laser diode package 404, which extends around the sides of the printed circuit board, rather than directly through the printed circuit board to the thermal path utilized by the laser diode driver. Provides a heat path for the heat. The step height between the first part 410 and the second part 414 and the laser diode package 404 and the second part so as to provide the target amount of thermal insulation between the laser diode package 404 and the printed circuit board. The distance between the step portion 415 that separates the first portion 410 and the second portion 414 may be designed.

FIG. 5 shows a cross section of an embodiment of the optical assembly 500. The optical assembly 500 includes a printed circuit board 502, a coupler 504 attached to the printed circuit board 502, and a laser diode package 506 disposed within the coupler 504. As mentioned above, the coupler 504 includes a first portion 510, a second portion 512, and a third portion 514, indicated by their respective regions between the dashed lines. It will be appreciated that three parts can be formed from a single piece of material or otherwise integrated into one.

As shown in FIG. 5, the first portion 510 includes a receptacle 516 accommodating the laser diode package 506, separating the printed circuit board 502 and the laser diode driver 520 from the printed circuit board 502 via a gap 518. Thermally insulate from the laser diode package 506 mounted inside the coupler 504. The receptacle 516 includes an aperture 521 extending from the receptacle 516 through the coupler 504 and allows light emitted by the laser diode to pass through. The receptacle 516 can be configured to be closely matched in shape with the laser diode package 506 to help ensure good thermal conductivity between the laser diode package 506 and the coupler 504. The electrical lead 522 of the laser diode package 506 can extend through the gap 518 between the printed circuit board 502 and the laser diode package 506 and be electrically connected to the laser diode driver. The gap 518 may contain any suitable material that thermally separates the laser diode package 506 from the printed circuit board 502. In some embodiments, the gap 518 can be an air gap. In other embodiments, other heat insulating materials may be included within the gap 518.

As illustrated, the laser diode package 506 is located on the side of the printed circuit board 502 opposite the laser diode driver 520. In some embodiments, the laser diode package 506 and / or the coupler 504 is positioned opposite to the laser diode driver to help shorten the electrical leads 522 and reduce the inductance of the laser diode package 506 to other arrangements. obtain. In other embodiments, the laser diode driver and laser diode package can be laterally biased (offset) by an appropriate amount.

The laser diode driver 520 may be coupled to the heat sink 524 via a thermally conductive interface material 526 located between the heat sink 524 and the laser diode driver 520. The thermally conductive interface material 526 may include any suitable material that provides a thermally conductive path between the laser diode driver 520 and the heat sink 524. Heat from the laser diode driver 520 may be conducted towards fins 528 of the heat sink 524 for dissipation away from the optical assembly 500.

The heat sink 524 may be in direct contact and / or interface connection with one or more locations on the back surface of the printed circuit board 502. In some embodiments, the portion of the heat sink 524 that contacts the printed circuit board 502 is separated from the portion of the heat sink 524 that receives heat from the laser diode driver 520 through a first gap 530, and thus the laser diode. It may come into contact with the printed circuit board 502 at a first location away from the driver 520. The heat sink 524 is printed in a second location away from the laser diode driver 520 through the second gap 532 so that the laser diode driver 520 can be positioned between the first gap 530 and the second gap 532. It can also come into contact with the circuit board 502. The first gap 530 and the second gap 532 thermally separate the laser diode driver 520 from the printed circuit board 502 and / or other elements of the optical assembly 500, any suitable material containing non-limiting air. Can also be included.

The heat sink 524 may be coupled to the coupler 504 via a thermal interface material 534 located between the coupler 504 and the heat sink 524. In some embodiments, the heat sink 524 may couple to the coupler 504 adjacent to a second location of contact between the heat sink 524 and the printed circuit board 502. In a illustrated embodiment, a third portion of the coupler 504 extends around the sides of the printed circuit board 502 and interfaces with the heat sink 524 to conduct a first portion for conducting heat from the laser diode package 506. It provides a second heat path that is different from the heat path of. The second gap 532 can be larger than the first gap 530 to help thermally isolate the thermal path from the laser diode driver and laser diode package to the heat sink. Although FIG. 5 illustrates one coupler assembly and corresponding laser diode driver for clarity, it is understood that some embodiments may include multiple coupler assemblies and corresponding laser diodes mounted on a printed circuit board. Will be done.

FIG. 6 shows an embodiment of method 600 for manufacturing an optical assembly. Method 600 comprises attaching the laser diode driver to the printed circuit board at 602 and attaching the laser diode package to the printed circuit board at 604. For example, the laser diode driver can be mounted on the back of the printed circuit board, while the laser diode package is mounted on the front of the printed circuit board. The method further comprises coupling the laser diode package to the printed circuit board via a coupler that contacts the printed circuit board, as shown in 606. The coupler can come into contact with the printed circuit board at a location laterally offset from the laser diode driver, as shown at 608, and can help separate the laser diode package from the printed circuit board, as shown at 610.

Method 600 may further include coupling the heat sink to the laser diode driver at 612. This can result in a first heat path that conducts heat from the laser diode driver for dissipation. Further, as shown in 614, method 600 further comprises coupling the heat sink to the coupler to provide a second thermal path extending around the sides of the printed circuit board, as described above with respect to FIG. obtain. In addition, as shown at 616, method 600 may optionally include placing a thermal interface material between the heat sink and the coupler. For example, the thermal interface material can ensure a low thermal resistance path from the coupler to the heat sink to allow heat to be conducted from the laser diode package around the printed circuit board to the heat sink. Method 600 may be repeated to mount multiple laser diode drivers and multiple corresponding laser diode packages and couplers on the printed circuit board. Each laser diode package may have a corresponding coupler that provides a thermal path to the heat sink.

Thus, the embodiments described herein provide a separate thermal path for the laser diode package and the laser diode driver. By separating these paths while maintaining close proximity between the electrically connected components of these elements, thermal efficiency can be maintained while at the same time reducing induction losses. Its configuration uses fewer thermoelectric coolers or does not use thermoelectric coolers and more when compared to configurations that do not include a separate heat path for the laser diode package and the corresponding laser diode driver located in close proximity. It can enable high speed performance.

In some embodiments, the methods and processes described herein may be associated with the computer system (computing system) of one or more computer devices. Specifically, such methods and systems may be implemented as computer-application programs or services, application-programming interfaces (APIs), libraries, and / or other computer-program products.

FIG. 7 graphically illustrates a non-limiting embodiment of a computer system 700 that may perform one or more of the methods and processes described above. The computer system 700 is shown in a simplified form. Computer system 700 includes one or more game consoles, personal computers, control devices, server computers, tablet computers, home entertainment computers, network computing devices, mobile computing devices, mobile communication devices (eg smartphones). , And / or may take the form of other computer devices, including but not limited to the computer device 106 of FIG.

The computer system 700 includes a logic machine 702 (logic machine) and a storage machine machine 704 (storage machine). Computer system 700 may optionally include display subsystem 706, input subsystem 708, communication subsystem 710, and / or other components not shown in FIG.

Logical machine 702 includes one or more physical devices configured to execute instructions. For example, a logical machine may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical structures. .. Performing such instructions, performing tasks, performing data types, transforming the state of one or more components, achieving technical effects, or otherwise desired. Results can be reached.

A logical machine can include one or more processes that are configured to execute software instructions. Additional or alternative, a logical machine may include one or more hardware or firmware logical machines that are configured to execute hardware or firmware instructions. The processor of the logical machine can be single-core or multi-core, and the instructions executed on it can be configured for sequential processing, parallel processing, and / or distributed processing. The individual components of a logical machine can be distributed among two or more separate devices that can be located remotely and / or configured for collaborative processing. The features of a logical machine can be virtualized and executed by remotely accessible network computer devices configured in a cloud computing configuration.

Storage machine 704 is configured to hold and / or store machine-readable instructions that can be executed by the logical machine performing the methods and processes described herein, or one or more physical units. Including devices. For example, the logical machine 702 may be in operational contact with the storage machine 704. When such methods and processes are implemented, the state of storage machine 704 can be transformed to hold, for example, different data.

The storage machine 704 may include removable and / or built-in devices. The storage machine 704 may include, among other things, optical memory (eg, CD, DVD, HD-DVD, Blu-ray disc, etc.), semiconductor memory (eg, RAM, EPROM, EEPROM, etc.), and / or magnetic memory (eg, hard disk). Drives, floppy® disk drives, tape drives, MRAM, etc.) may be included. The storage machine 704 is machine readable volatile, non-volatile, dynamic, static, read / write, read only, random access, sequential access, location-addressable. ), File-addressable, and / or content-addressable devices can be included.

It will be appreciated that the storage machine 704 includes one or more physical devices. However, the features of the instructions described herein can be programmed by a communication medium (eg, an electromagnetic signal, an optical signal, etc.) that is not held by the physical device for a finite duration.

The features of the logical machine 702 and the storage machine 704 can be integrated into one or more hardware-logical components. Such hardware-logical components include, for example, field programmable gate arrays (FPGAs), programmatic and application-specific integrated circuits (PASIC / ASIC), program-specific and application-specific standards (PSSP / ASSP), etc. It may include system-on-chip (SOC), and complex programmable logic device (CPLD).

When the display subsystem 706 is included, the display subsystem 706 may be used to provide a visual representation of the data held by the storage machine 704. This visual display can take the form of a graphic user interface (GUI). Since the methods and processes described herein modify the data held by the storage machine and thus transform the state of the storage machine, the state of the display subsystem 706 is also transformed and the underlying data. Can visually present changes in. The display subsystem 706 may include one or more display devices that utilize virtually any kind of technology. Such a display device may be combined with a logical machine 702 and / or a storage machine 704 in a shared enclosure, or such a display device may be a peripheral display device. For example, the display subsystem 706 may include the display device 108 of FIG.

When including the input subsystem 708, the input subsystem 708 may include or interface with one or more user input devices, such as a keyboard, mouse, touch screen, microphone, or game controller. Can connect. For example, the input subsystem 708 may include or interface with the computer device 106 of FIG. In some embodiments, the input subsystem 708 may include, or interface with, a selective natural user input (NUI) component configuration. Such component configurations may be integrated, or such component configurations may be peripherals. The conversion and / or processing of input actions can be processed on or off the board. Illustrative NUI component configurations include microphones for speech and / or speech recognition, machine vision and / or infrared, color, stereo, and / or depth cameras for gesture recognition, motion detection and /. Or head tracking device for intention recognition (head) It may include a tracker, an eye tracker, an accelerometer, and / or a gyroscope, and an electric field sensing component configuration for assessing brain activity.

When including the communication subsystem 710, the communication subsystem 710 may be configured to communicatively couple the computer system 700 with one or more other computer systems. The communication subsystem 710 may include wired and / or wireless communication devices that are compatible with one or more different communication protocols. As a non-limiting example, the communication subsystem 710 may be configured for communication over a radiotelephone network or over a wired or wireless premises or wide area network. In some embodiments, the communication subsystem may allow the computer system 700 to send and / or receive messages from other devices over a network such as the Internet.

The configurations and / or approaches described herein are exemplary in nature, as many variations are possible, and these particular embodiments or examples should not be considered in a limited sense. Will be understood. The particular routine or method described herein may present one or more of any number of processing strategies. Therefore, the various acts exemplified and / or described may be performed in the order illustrated and / or described, in other orders, or in parallel, or may be omitted. Similarly, the order of the processes described above can be changed.

The subject matter of this disclosure is all new and non-trivial combinations of various processes, systems, and configurations, other features, functions, actions, and / or characteristics disclosed herein, and all their equivalents. ) And sub-combinations.