PCB optical isolation by non-uniform gripping pad stack
阅读说明:本技术 通过非均匀抓握焊盘堆叠进行的pcb光学隔离 (PCB optical isolation by non-uniform gripping pad stack ) 是由 A.塔佐利 B.加森德 于 2018-05-22 设计创作,主要内容包括:示例性印刷电路板(PCB)可以包括延伸穿过PCB的至少一层的过孔。PCB还可以包括连接到过孔并位于PCB的第一金属层内的第一抓握焊盘。第一抓握焊盘可以具有第一尺寸。PCB可以进一步包括连接到过孔并位于PCB的第二金属层内的第二抓握焊盘。第二抓握焊盘可以具有大于第一尺寸的第二尺寸。第二抓握焊盘可以与第一金属层中的金属特征部的一部分水平重叠,以阻挡入射在PCB的第一侧上的光通过过孔附近的介电材料区域透射到PCB的第二侧。(An exemplary Printed Circuit Board (PCB) may include a via extending through at least one layer of the PCB. The PCB may further include a first grip pad connected to the via and located within the first metal layer of the PCB. The first grip pad may have a first size. The PCB may further include a second capture pad connected to the via and located within a second metal layer of the PCB. The second grip pad may have a second size larger than the first size. The second grip pad may horizontally overlap a portion of the metal feature in the first metal layer to block light incident on the first side of the PCB from being transmitted to the second side of the PCB through the region of dielectric material near the via.)
1. A Printed Circuit Board (PCB), comprising:
a via extending through at least one layer of the PCB;
a first grasping pad connected to the via and located within a first metal layer of the PCB, wherein the first grasping pad has a first size; and
a second grip pad connected to the via and located within a second metal layer of the PCB, wherein the second grip pad has a second dimension greater than the first dimension, and wherein the second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the PCB from being transmitted to the second side of the PCB through an area of dielectric material proximate the via.
2. The PCB of claim 1, further comprising:
a light sensor connected to the second side of the PCB and configured to sense light incident on the light sensor from the second side of the PCB, wherein the second grip pad blocks light incident on the first side of the PCB from being transmitted to the second side of the PCB through an area of dielectric material near the via and striking the light sensor by horizontally overlapping a portion of the metal feature in the first metal layer.
3. The PCB of claim 2, wherein the light sensor forms part of a light detection and ranging (LIDAR) system, and wherein the PCB further comprises:
a housing disposed about the light sensor and configured to direct light from a portion of an environment onto the light sensor through an aperture; and
a gasket surrounding the light sensor and disposed between the PCB and the housing, wherein the gasket is configured to block light incident on an interface between the PCB and the housing from reaching the light sensor.
4. The PCB of claim 1, further comprising:
a third grip pad connected to the via and located within a third metal layer of the PCB, wherein the third grip pad has a third dimension that is less than the second dimension, wherein the second metal layer is positioned between the first metal layer and the third metal layer, wherein the second grip pad is horizontally interposed between the portion of the metal feature in the first metal layer and a portion of another metal feature in the third metal layer to block transmission of light incident on the first side of the PCB to the second side of the PCB through a region of dielectric material near the via.
5. The PCB of claim 1, further comprising:
a first plurality of metal layers, wherein the first plurality of metal layers comprises a first metal layer, and wherein each respective metal layer of the first plurality of metal layers comprises a corresponding grip pad having a first size and connected to the via;
a second plurality of metal layers, wherein the second plurality of metal layers comprises a second metal layer, wherein each respective metal layer of the second plurality of metal layers comprises a respective grip pad having a second dimension and connected to the via, wherein each grip pad corresponding to the second plurality of metal layers is horizontally interposed between a portion of the first metal feature in at least one metal layer of the first plurality of metal layers and a portion of the second metal feature in at least one other metal layer of the first plurality of metal layers to block transmission of light incident on the first side of the PCB to the second side of the PCB through a region of dielectric material proximate the via.
6. The PCB of claim 1, wherein the first gripping pad is a metal annular ring surrounding the via in a first metal layer, wherein the first dimension is a first diameter, wherein the second gripping pad is a metal annular ring surrounding the via in a second metal layer, and wherein the second dimension is a second diameter.
7. The PCB of claim 1, wherein the second grip pad horizontally overlaps respective portions of the plurality of metal features in the first metal layer to block light incident on the first side of the PCB from being transmitted to the second side of the PCB through respective areas of dielectric material surrounding the via.
8. The PCB of claim 1, wherein a volume of said via is filled with a metal to block light incident on said via from a first side of the PCB from being transmitted through said via to a second side of the PCB.
9. The PCB of claim 1, wherein at least one of the first or second metal layers is a metal plane spanning an area of the PCB, wherein the metal plane blocks light incident on a first side of the PCB from being transmitted through the area of the PCB spanned by the metal plane to a second side of the PCB, and wherein the metal plane is a ground plane or a power plane.
10. A method for manufacturing a Printed Circuit Board (PCB), comprising:
providing a PCB substrate;
forming a first metal layer on the PCB substrate, wherein the first metal layer includes a first grip pad for a via, and wherein the first grip pad has a first size;
forming a second metal layer on the PCB substrate, wherein the second metal layer includes a second grip pad for the via, wherein the second grip pad has a second dimension that is greater than the first dimension, and wherein the second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block transmission of light incident on the first side of the PCB to the second side of the PCB through an area of the PCB substrate near the via; and
forming the via, wherein the via electrically connects the first grip pad to the second grip pad.
11. The method of claim 10, further comprising:
bonding a light sensor to the second side of the PCB, wherein the light sensor is configured to sense light incident on the light sensor from the second side of the PCB, and wherein, by horizontally overlapping a portion of the metal feature in the first metal layer, the second grip pad is configured to block light incident on the first side of the PCB from transmitting through the PCB substrate area proximate the via to the second side of the PCB and impinging on the light sensor.
12. The method of claim 11, further comprising:
providing a housing around the light sensor, wherein the housing is configured to direct light from a portion of an environment onto the light sensor through an aperture;
providing a gasket between the PCB and the housing, wherein the gasket surrounds the light sensor, and wherein the gasket is configured to block light incident on an interface between the PCB and the housing from reaching the light sensor; and
securing the housing to the PCB with the gasket therebetween.
13. The method of claim 10, further comprising:
forming a third metal layer on the PCB substrate, wherein the third metal layer includes a third grip pad for the via, wherein the third grip pad has a third dimension that is less than the second dimension, wherein the second metal layer is positioned between the first metal layer and the third metal layer, wherein the second grip pad is horizontally interposed between the portion of the metal feature in the first metal layer and a portion of another metal feature in the third metal layer to block light incident on the first side of the PCB from being transmitted through an area of the PCB substrate near the via to the second side of the PCB.
14. The method of claim 10, wherein the first grip pad is a metal annular ring surrounding the via in the first metal layer, wherein the first dimension is a first diameter, wherein the second grip pad is a metal annular ring surrounding the via in the second metal layer, and wherein the second dimension is a second diameter.
15. The method of claim 10, wherein the second grip pad horizontally overlaps respective portions of the plurality of metal features in the first metal layer to block light incident on the first side of the PCB from being transmitted to the second side of the PCB through respective areas of the PCB substrate surrounding the via.
16. The method of claim 10, wherein forming the via comprises:
filling a volume of the via with a metal to block light incident on the via from a first side of the PCB from being transmitted through the via to a second side of the PCB.
17. The method of claim 10, further comprising:
generating, by a computing device, a layout of a PCB, wherein the layout defines locations of (i) vias, (ii) first grip pads, (iii) second grip pads, and (iv) metal features in a first metal layer on the PCB substrate, and wherein the computing device is configured to identify light-transmissive regions of the PCB substrate; and
based on the generated layout, one or more regions of the PCB substrate that are transparent to light are identified.
18. A system, comprising:
a Printed Circuit Board (PCB) including a first side and a second side;
a light sensor connected to the second side of the PCB and configured to sense light incident on the light sensor from the second side of the PCB;
a via extending through at least one layer of the PCB;
a first grasping pad connected to the via and located within a first metal layer of the PCB, wherein the first grasping pad has a first size; and
a second grip pad connected to the via and located within a second metal layer of the PCB, wherein the second grip pad has a second dimension that is greater than the first dimension, and wherein the second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the PCB from being transmitted through an area of transmissive PCB material near the via to the second side of the PCB and impinging on the light sensor.
19. The system of claim 18, further comprising:
a light detection and ranging (LIDAR) device, wherein the light sensor forms a portion of the LIDAR device and is disposed within a housing of the LIDAR device;
a housing disposed about the light sensor within the housing, wherein the housing is configured to direct light from a portion of an environment onto the light sensor through an aperture; and
a gasket surrounding the light sensor and disposed between the PCB and the housing, wherein the gasket is configured to block light incident on an interface between the PCB and the housing from reaching the light sensor.
20. The system of claim 18, further comprising:
a light detection and ranging (LIDAR) device, wherein the light sensor forms part of the LIDAR device; and
a vehicle configured to operate autonomously based on data from the LIDAR device, wherein the LIDAR device and PCB are mounted to the vehicle.
Background
Printed Circuit Boards (PCBs) mechanically support and electrically connect electronic components by means of conductive traces, pads, vias (vias) and other metal features (metallificates) disposed between (i.e., above or below) and non-conductive substrates. Components such as resistors, capacitors and active semiconductor devices are typically soldered onto the PCB, but may also be directly embedded in the substrate. The PCB may be single-sided (i.e. comprising only one metal layer), double-sided (i.e. comprising two metal layers) or multi-layered (i.e. comprising a plurality of metal layers). Metal features in different metal layers of a PCB may be electrically connected by vias.
Disclosure of Invention
In an exemplary embodiment, a Printed Circuit Board (PCB) may have non-uniformly sized (non-uniform) via capture pads (via catch pads) that overlap or are interposed between metal features in adjacent metal layers of the PCB. Thus, the non-uniformly sized via capture pad may provide an obstruction to light transmission through other transmissive dielectric regions of the PCB around the via. The overlap or insertion allows the two sides of the PCB to be optically isolated from each other. Thus, components mounted on the first side of the PCB may be isolated from light and other electromagnetic radiation incident on the second side of the PCB, and vice versa.
In a first embodiment, a Printed Circuit Board (PCB) is provided that includes a via extending through at least one layer of the PCB. The PCB further includes a first capture pad connected to the via and located within the first metal layer of the PCB. The first grip pad has a first size. The PCB further includes a second capture pad connected to the via and located within a second metal layer of the PCB. The second grip pad has a second size greater than the first size. Additionally, the second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the PCB from being transmitted to the second side of the PCB through the region of dielectric material near the via.
In a second embodiment, a method of manufacturing a Printed Circuit Board (PCB) is provided that includes providing a PCB substrate. The method also includes forming a first metal layer on the PCB substrate. The first metal layer includes a first capture pad for a via. The first grip pad has a first size. The method additionally includes forming a second metal layer on the PCB substrate. The second metal layer includes a second capture pad for a via. The second grip pad has a second size greater than the first size. The second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the PCB from being transmitted to the second side of the PCB through the PCB substrate area near the via. The method further comprises forming (create) a via. A via electrically connects the first grip pad to the second grip pad.
In a third embodiment, a system is provided that includes a Printed Circuit Board (PCB) including a first side and a second side. The system also includes a light sensor connected to the second side of the PCB and configured to sense light incident on the light sensor from the second side of the PCB. The system additionally includes a via extending through at least one layer of the PCB. The system further includes a first capture pad connected to the via and located within the first metal layer of the PCB. The first grip pad has a first size. The system still further includes a second capture pad connected to the via and located within a second metal layer of the PCB. The second grip pad has a second size greater than the first size. The second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the PCB from being transmitted through the transmissive PCB material region near the via to the second side of the PCB and impinging on the light sensor.
In a fourth embodiment, a device formed by a process including providing a Printed Circuit Board (PCB) substrate is provided. The process also includes forming a first metal layer on the PCB substrate. The first metal layer includes a first capture pad for a via. The first grip pad has a first size. The process additionally includes forming a second metal layer on the PCB substrate. The second metal layer includes a second capture pad for a via. The second grip pad has a second size greater than the first size. The second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the PCB from being transmitted to the second side of the PCB through the PCB substrate area near the via. The process further includes forming a via. A via electrically connects the first grip pad to the second grip pad.
In a fifth embodiment, an Integrated Circuit (IC) device is provided that includes a via extending through at least one layer of the IC device. The IC device also includes a first capture pad connected to the via and located within the first metal layer of the IC device. The first grip pad has a first size. The IC device further includes a second capture pad connected to the via and located within a second metal layer of the IC device. The second grip pad has a second size greater than the first size. Additionally, the second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the IC device from being transmitted to the second side of the IC device through the transmissive material region near the via.
In a sixth embodiment, a method of fabricating an Integrated Circuit (IC) device is provided that includes providing an IC substrate. The method also includes forming a first metal layer on the IC substrate. The first metal layer includes a first capture pad for a via. The first grip pad has a first size. The method additionally includes forming a second metal layer on the IC substrate. The second metal layer includes a second capture pad for a via. The second grip pad has a second size greater than the first size. The second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the IC device from being transmitted through an area of the IC substrate near the via to the second side of the IC device. The method further includes forming a via. A via electrically connects the first grip pad to the second grip pad.
In a seventh embodiment, a system is provided that includes an Integrated Circuit (IC) device having a first side and a second side. The system also includes a light sensor connected to the second side of the IC device and configured to sense light incident on the light sensor from the second side of the IC device. The system additionally includes a via extending through at least one layer of the IC device. The system further includes a first capture pad connected to the via and located within the first metal layer of the IC device. The first grip pad has a first size. The system still further includes a second capture pad connected to the via and located within a second metal layer of the IC device. The second grip pad has a second size greater than the first size. The second grip pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the IC device from being transmitted through the transmissive IC device substrate material region near the via to the second side of the IC device and impinging on the photosensor.
In an eighth embodiment, a device formed by a process including providing an Integrated Circuit (IC) substrate is provided. The process also includes forming a first metal layer on the IC substrate. The first metal layer includes a first capture pad for a via. The first grip pad has a first size. The process additionally includes forming a second metal layer on the IC substrate. The second metal layer includes a second capture pad for a via. The second grip pad has a second size greater than the first size. The second capture pad horizontally overlaps a portion of the metal feature in the first metal layer to block light incident on the first side of the IC from being transmitted to the second side of the IC through an area of the IC substrate proximate the via. The process further includes forming a via. A via electrically connects the first grip pad to the second grip pad.
These and other embodiments, aspects, advantages, and alternatives will become apparent to one of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings. Further, it should be understood that this summary and other descriptions and figures provided herein are intended to illustrate embodiments by way of example only and, therefore, that many variations are possible. For example, structural elements and process steps may be rearranged, combined, distributed, eliminated, or otherwise altered while remaining within the scope of the claimed embodiments.
Drawings
Fig. 1 shows a block diagram of an example LIDAR device, according to an example embodiment.
FIG. 2 shows a simplified block diagram of a vehicle according to an example embodiment.
Fig. 3 shows several views of a LIDAR device configured on top of a vehicle, according to an example embodiment.
Fig. 4 illustrates a side cross-sectional view of a printed circuit board having uniform via pads, according to an example embodiment.
Fig. 5A illustrates a side cross-sectional view of a printed circuit board having non-uniform via pads, according to an example embodiment.
Fig. 5B illustrates a side cross-sectional view of another printed circuit board having non-uniform via pads, according to an example embodiment.
Fig. 5C illustrates a side cross-sectional view of an additional printed circuit board having non-uniform via pads, according to an example embodiment.
Fig. 6A illustrates a top view of a printed circuit board with uniform via pads according to an example embodiment.
Fig. 6B illustrates a top view of a printed circuit board having non-uniform via pads, according to an example embodiment.
Fig. 7 illustrates a light sensor housed within a housing according to an example embodiment.
FIG. 8 illustrates example operations for manufacturing a printed circuit board according to example embodiments.
Detailed Description
Example methods, devices, and systems are described herein. It should be understood that the words "example" and "exemplary" are used herein to mean "serving as an example, instance, or illustration. Any embodiment or feature described herein as "exemplary" or "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or features unless so stated. Other embodiments may be utilized, and other changes may be made, without departing from the scope of the subject matter presented herein.
Accordingly, the example embodiments described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations.
Throughout this specification, the articles "a" or "an" are used to introduce elements of example embodiments. Any reference to "a" or "an" means "at least one" and any reference to "the" means "the at least one" unless otherwise indicated herein or otherwise clearly indicated by the context. The use of the conjunction "or" in a list of at least two terms described is intended to indicate any listed term or any combination of listed terms.
The use of ordinal numbers (such as "first," "second," "third," etc.) is for distinguishing between various elements and not for indicating a particular order of such elements. For the purposes of this specification, the terms "plurality" and "a plurality" mean "two or more" or "more than one"
Further, features shown in each of the figures may be used in combination with each other, unless the context otherwise implies. Thus, the drawings should generally be regarded as forming aspects of one or more general embodiments, with the understanding that not all illustrated features are essential to each embodiment. In the drawings, like reference numerals generally refer to like parts throughout the various views unless the context dictates otherwise. Further, unless otherwise noted, the drawings are not to scale and are for illustrative purposes only. Moreover, the drawings are merely representative, and not all of the components are shown. For example, additional structural or constraining components may not be shown.
Additionally, any enumeration of elements, blocks or steps in the present description or claims is for clarity. Thus, this enumeration should not be interpreted as requiring or implying that such elements, blocks or steps follow a particular arrangement or are carried out in a particular order.
SUMMARY
Example embodiments of non-uniform via (i.e., vertical interconnect via) grip pads, and methods and systems related thereto, are disclosed herein. Uneven grip pads can block light from passing through a Printed Circuit Board (PCB) and cause unwanted triggering of sensitive light sensors. The grip pads may be implemented in, for example, a Light Detection And Ranging (LIDAR) PCB or other application that uses a Light sensitive sensor. LIDAR systems may use one or more emitters (e.g., laser diodes) to emit light and one or more corresponding receivers (e.g., sensors) to receive backlight to measure the distance (and in some cases the velocity) of an object in the line of sight of the LIDAR. The receiver circuit may be based on very sensitive elements such as PhotoMultiplier tubes (PMTs), Avalanche Photodiodes (APDs) and Silicon photomultipliers (sipms) working with the amplifier circuit, which may allow detection of single photons. This high sensitivity to light may improve LIDAR resolution and range, but may present challenges in designing a system in which all LIDAR components, particularly the area around the sensitive light sensor, are properly shielded to prevent unintended or loose (loose) photons (photos) that may cause undesirable effects (e.g., unwanted triggering of circuits, increased current consumption, etc.). In one embodiment, a non-uniform via pad stack (in combination with filled vias) is employed so that light can be reflected off the PCB or internally absorbed by the metallization layer rather than passing through the PCB. Designing the via pad stack in a manner that prevents loose photons from passing through the PCB may also allow an inexpensive solder mask (e.g., green) to be used with the light sensitive PCB.
A via capture pad is a conductive metal pad around a via, typically in the shape of an annular ring. In some cases, the via capture pad may provide an electrical connection between the via and at least one metal feature in a corresponding metal layer of the PCB. However, in other cases, the via grip pad may not be electrically connected to any metal feature in the corresponding metal layer (e.g., the grip pad of the stacked microvias). The non-uniformly sized via capture pad may extend into the transmissive area of the PCB around the via, thereby providing an obstruction that impedes light transmission through other transmissive areas around the via. In some cases, the non-uniformly sized gripping pads may also overlap or interpose with metal features (e.g., traces, planes, pads) in adjacent metal layers of the PCB to further increase the likelihood of blocking light transmission through other transmissive areas of the PCB around the vias. The unevenly sized gripping pads allow the two sides of the PCB to be optically isolated from each other. Thus, components mounted on the first side of the PCB may be isolated from light and other electromagnetic radiation incident on the second side of the PCB, and vice versa.
Conventionally, vias include a capture pad having about the same dimensions (i.e., containing variations in manufacturing tolerances and manufacturing process variations). A minimum gap space (gap) or gap (gap) composed of a transmissive dielectric PCB substrate material may be provided between each of the capture pads and any nearby metal features within the same metal layer. The gap space may be used to physically separate and electrically isolate the grip pad from nearby metal features and reduce the possibility of inadvertent physical electrical connections and flashovers (flashovers). However, since the dimensions of the via capture pad are uniform along the height of the via, this may result in a dielectric PCB substrate area spanning the thickness of the PCB through which light may be transmitted between the two sides of the PCB. Thus, the light sensitive components connected to the first side of the PCB may be inadvertently triggered by light or other electromagnetic radiation incident on the second side of the PCB and transmitted through the transmissive dielectric PCB substrate area around the via. In contrast, vias with non-uniform grip pads increase the likelihood of blocking light transmission through the transmissive dielectric PCB substrate area around the via, thereby reducing the amount of light transmitted through the PCB by including at least one grip pad extending through the dielectric area.
A non-uniform via capture pad may be used with PCBs having two or more metal layers. In one example, the PCB may include a via extending through at least one layer of the PCB. That is, the PCB may include at least two metal layers separated by a dielectric substrate layer through which the vias extend. The via may include at least two grip pads, each grip pad connected to the via and located within a corresponding one of the metal layers. A first capture pad having a first size may be connected to the via and may be located within a first metal layer of the PCB. The second capture pad may be connected to the via and may be located within a second metal layer of the PCB. In some examples, the first and second grip pads may electrically connect the via to the first and second metal layers, respectively. The second grip pad may have a second dimension that is larger than the first dimension and may therefore extend through the region of the dielectric substrate material surrounding the via. In some cases, due to the larger second dimension, the second grip pad may horizontally overlap a portion of the metal feature in the first metal layer.
As a result of the second dimension being larger than the first dimension, the second grip pad may extend through a PCB substrate area, which may be light transmissive if the first and second grip pads have the same dimension. Thus, the larger second grasping pad blocks light incident on the first side of the PCB from being transmitted through the area of the dielectric PCB substrate proximate the via to the second side of the PCB. The metal features in the second metal layer may be routed (routed) to accommodate the increased size of the second capture pad and to maintain a desired gap (i.e., pitch or spacing) between the second capture pad and the metal features. Similarly, in some embodiments, the metal features in the first metal layer may be routed to form a continuous horizontal overlap between the metal features in the first metal layer and the second grip pad along the entire circumference of the second grip pad.
The PCB may include an additional metal layer through which the via extends, and an additional capture pad connected to the via and located within the additional metal layer. The relative sizes of the capture pads in the different metal layers may be selected to increase or maximize the complexity of the path (e.g., path length, number of reflections, etc.) that light must follow in order to move from the first side of the PCB to the second side of the PCB, thereby reducing or minimizing the probability and degree of transmission.
In one example, the vias may include grip pads having two sizes that may alternate along the metal layer to increase the degree of overlap and insertion of the grip pads with metal features in adjacent metal layers (i.e., metal layers above and below the metal layer containing a particular grip pad). In another example, via anti-pads (i.e., the gap regions around vias in metal layers that do not include via grip pads) may be configured between the largest via grip pads to similarly increase the degree of overlap and insertion. In further examples, the arrangement of the grip pads may be selected to block light incident on the top surface of the PCB at a particular angle.
The metal features in other areas of the PCB may also be designed and routed to ensure that at each point along the PCB area there is at least one metal feature in at least one metal layer that blocks light from being transmitted directly between the two sides of the PCB. The metal features may be further designed and routed to ensure that the at least one metal feature horizontally overlaps with at least one other metal feature in another metal layer. Thus, the PCB may be designed such that there are no points along an area of the PCB where light may be directly transmitted through the PCB (i.e., without reflection from metal features within the PCB). It is worth noting that some light may still be transmitted by following an indirect zig-zag path. However, the likelihood of such indirect transmission decreases with increasing degree of overlap between metal features. Further, even if the light is not reflected back out of the first side, it is likely that the light will be absorbed inside the metal layer before reaching the second side. Thus, the techniques described herein effectively reduce the likelihood and amount of light transmission through the PCB. That is, the probability of a single photon transmitting through the PCB may be reduced, thereby reducing the proportion of light incident on the PCB that is transmitted through the PCB.
In some embodiments, the light sensor may be connected to the second side of the PCB. The light sensor may be configured to sense light incident on the light sensor from the second side of the PCB. That is, light incident on the first side of the PCB, transmitted through the PCB, and incident on the light sensor may constitute undesirable noise. Thus, by horizontally overlapping a portion of the metal feature in the first metal layer, the second capture pad may operate to reduce the level of electromagnetic noise reaching the photosensor.
In some cases, the light sensor may form part of a light detection and ranging (LIDAR) device, which may be used as a sensor to map an environment. The environment map may be used by, for example, a robotic device or a vehicle to perform operations in the environment. The housing may be disposed around the light sensor. The housing may include an aperture configured to direct light from a portion of the environment onto the light sensor. The light directed onto the light sensor may include light emitted by a light source of the LIDAR device that has been reflected by physical features in the environment, allowing the environment to be mapped based on, for example, time of flight of the light emitted by the light source.
A gasket surrounding the light sensor may be disposed between the second side of the PCB and the housing to further shield the light sensor from other optical noise. In particular, the gasket may be configured to block light incident on an interface between the PCB and the housing. Thus, a PCB with non-uniform via gripping pads, housing, and gasket can cooperate to reduce the amount of optical noise reaching the light sensor, thereby increasing the signal-to-noise ratio.
PCBs with non-uniform via capture pads may be used for other applications requiring electromagnetic shielding. For example, the PCB may be used to provide a more effective electromagnetic shielding to prevent radiation from being incident on a first side of the PCB of other electromagnetic sensors or other components sensitive to electromagnetic radiation connected to a second side of the PCB. PCBs with non-uniform grip pads may be used to provide shielding, for example, from electromagnetic radiation having wavelengths that are smaller than the gap size (i.e., slit size) in the dielectric PCB substrate region, and thus propagate through the gap via line-of-sight propagation (e.g., ultraviolet, visible, infrared).
PCBs with non-uniform gripping pads can be manufactured using standard PCB manufacturing processes including photolithography, metal etching, metal plating, lamination, solder mask applications, text printing, Computer Numerical Control (CNC) milling, laser drilling, and the like. These processes may be performed manually, automatically, or by a combination of manual and automatic steps. Similarly, the process of designing a PCB with non-uniform via-gripping pads may be performed by a combination of manual and automated steps. For example, PCB Design software may be programmed to include a Design Rule Check (DRC) that verifies whether the PCB includes any point along its area that is directly transparent to light. The PCB design software may be further programmed to identify and indicate locations that do not comply with the design rules, and in some embodiments, to propose a potential redesign of the metal features to comply with the design rules.
A non-uniform via capture pad may also be implemented on an Integrated Circuit (IC) device other than a PCB to block light transmission through a transmission region of the IC device surrounding the via. The non-uniform grip pads, as well as any other techniques described herein, may be used in conjunction with, or in place of, the IC package to block light transmission through the IC. A non-transmissive IC package may block the transmission of light through the packaged portion of the IC. However, some portions of the IC may be left unpackaged or may be packaged by a transmissive material, for example, to expose a portion of the IC to the environment (e.g., to expose a sensor on the IC to the environment). The uneven grip pads may be used to block light transmission through unencapsulated or otherwise exposed portions of the IC.
The obstruction can reduce the likelihood that light incident on the first side of the IC is transmitted to the second side of the IC and potentially impinges on the light sensitive portion of the IC on the second side thereof. Further, the obstacles may reduce the likelihood that electromagnetic radiation incident on either side of the IC reaches electronic components within the IC and potentially causes latch-up. Other benefits due to reduced light transmission through the IC are also possible.
Exemplary LIDAR device
Referring now to the drawings, fig. 1 is a simplified block diagram of a
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However, in other arrangements, the
Further, the one or more
In some arrangements, the one or more
In some embodiments, the
As noted, the
Additionally, the receiver 110 may be configured to scan the environment with a field of view (FOV). For example, the FOV of the receiver 110 may allow light to be detected along substantially the same angular range as the light emitted by the
In one embodiment, the receiver 110 may include an optical lens arranged to focus light reflected from one or more objects in the environment of the
Additionally, as noted, the receiver 110 may have a photodetector array, which may include one or more detectors configured to convert detected light (e.g., within the wavelength ranges mentioned above) into electrical signals indicative of the detected light. In practice, such photodetector arrays may be arranged in one of a variety of ways. For example, the detector may be disposed on one or more substrates (e.g., PCB, flexible PCB, etc.) and arranged to detect incident light traveling along the optical path from the optical lens. In general, components disposed on a substrate may be disposed above or below the substrate. Moreover, such a photodetector array may include any feasible number of detectors aligned in any feasible manner. For example, the photodetector array may comprise a 13 x 16 detector array. Note that this photodetector array is described for exemplary purposes only and is not meant to be limiting.
In general, the detectors of the array may take various forms. For example, the detector may take the form of a photodiode, an avalanche photodiode, a phototransistor, a camera, an Active Pixel Sensor (APS), a Charge Coupled Device (CCD), a low temperature detector, and/or any other light sensor configured to receive focused light having a wavelength within the emitted light wavelength range. Other examples are possible.
Further, as noted, the
In accordance with the present disclosure, the
With this arrangement, the controller may direct the
Also, the
Still further, as indicated, the
In accordance with the present disclosure, the
Still further, as indicated, the
In accordance with the present disclosure, the housing 122 may be coupled to the
Further, the housing 122 may have an aperture formed thereon, which may take any feasible shape and size. In this regard, the
Indeed, the housing 122 may be arranged as described above for various reasons. In particular, because the various components of the
However, in accordance with the present disclosure, the housing 122 may have an aperture that rotates with the
Given the various components of the
Exemplary vehicle System
FIG. 2 is a simplified block diagram of a vehicle 200 according to an example embodiment. The vehicle 200 may include a LIDAR device similar to the
Additionally, the systems and components shown may be combined or divided in a variety of ways. For example, the
The
The engine/
The
The transmission 222 may be configured to transmit mechanical power from the engine/
The wheels/
The
The
The
Radar unit 230 may be any sensor configured to sense objects in the environment in which vehicle 200 is located using radio signals. In some embodiments, in addition to sensing an object, radar unit 230 may additionally be configured to sense a speed and/or heading of the object.
Similarly, the laser rangefinder or
The camera 234 may be any camera (e.g., still camera, video camera, etc.) configured to grip an image of the environment in which the vehicle 200 is located. To this end, the camera may take any of the forms described above. The
The
The
The sensor fusion algorithm 244 may be an algorithm (or a computer program product storing an algorithm) configured to accept data from the
The
The navigation and
The
The
The user may input commands to the vehicle 200 using the
The microphone 256 may be configured to receive audio (e.g., voice commands or other audio input) from a user of the vehicle 200. Similarly, the
In one example, the
As shown, the
In some embodiments, the data storage 214 may contain instructions 216 (e.g., program logic) that are executable by the
As shown, the vehicle 200 further includes a
In some embodiments, vehicle 200 may include one or more elements in addition to or in place of those shown. For example, the vehicle 200 may include one or more additional interfaces and/or power sources. Other additional components are also possible. In such embodiments, the data storage 214 may further include instructions executable by the
Still further, while each of the components and systems are shown as being integrated in the vehicle 200, in some embodiments, one or more components or systems may be removably mounted on the vehicle 200 or otherwise connected (mechanically or electrically) to the vehicle 200 using a wired or wireless connection. The vehicle 200 may also take other forms.
Fig. 3 shows a right side view, a front view, a rear view, and a top view of the
Also, for example, the
Example PCB with optical isolation
Fig. 4 shows a lateral cross-section of an example Printed Circuit Board (PCB) 400. PCB400 includes
As shown in the cross-hatched pattern, the metal layers 402, 404, 406, and 408 of the PCB400 may be separated from each other by regions of PCB substrate material (e.g., FR-4 glass reinforced epoxy laminate). The metal layer may include various metal features such as traces (e.g., signal traces), contact pads (e.g., solder pads, via pads), and planes (e.g., ground planes, power planes). The various metal features may constitute electrical connections that cause the PCB400 to operate according to a desired design (e.g., power the
PCB400 also includes a via 410 electrically connecting at least two of
Although the
In general, the
Fig. 4 further shows a
However, the
Fig. 5A shows a lateral cross-section of another
In particular, the size of the
In one example, the
Further,
Such an overlap may result in
While some light may still pass through the PCB500 by following an indirect zig-zag path between the overlapping metal features, the uneven sizing of the
The degree of optical isolation between the first and second sides of the PCB may be further enhanced by filling (i.e., depositing material into its cavity) or covering (tent) (i.e., depositing material on top of) the
Further, in some embodiments, the degree of optical isolation may also be increased by using a dark (e.g., black) solder mask instead of a light (e.g., green) solder mask. The dark solder mask can absorb radiation in the relevant portion of the electromagnetic spectrum, thus blocking the transmission of light through the PCB. Notably, the minimum allowable feature size of the dark solder mask can be greater than the minimum allowable feature size of the light solder mask. Thus, in some applications or in some areas of a PCB that meet minimum size (e.g., pitch) requirements, a dark solder mask may be appropriate.
Notably, although the overlap of the
Additionally, although fig. 5A shows a PCB with four metal layers, a non-uniform via gripping pad may also be used with PCBs having more or fewer metal layers. In particular, fig. 5B shows a lateral cross-section of PCB524 (i.e., PCB500 with
In some embodiments, the
In some embodiments, the PCB may have more than four metal layers. Such a PCB may include, for example, three instances of
In some embodiments, the non-uniform via grasping pad may also include a via anti-pad. Fig. 5C shows a lateral cross-section of
The layout of the metal features within the layers of the PCB may be determined to improve or maximize the light shielding provided by the metal features of the PCB. For example, as shown in fig. 5C, a PCB layout may be determined such that the via antipad is positioned within the metal layer between two large via grasping pads (e.g., grasping
Such design parameters may be implemented as Design Rule Checks (DRC) in PCB design software. The DRC can identify and indicate areas or features of the PCB that violate design parameters (e.g., no direct light transmission path), thus allowing the designer to reroute any features that violate a rule in order to correct such violation. In some embodiments, PCB design software may be configured to automatically route or reroute metal features to meet the design rules described herein.
Fig. 6A and 6B show top views of areas of a three-layer PCB with uniform and non-uniform grip pads, respectively. In particular, fig. 6A shows the transmissive area that may result when using uniform vias to grip the pad. In layer 1, the PCB includes
When all of the via capture pads are uniform (as shown in fig. 6A), the spacing between the via capture pads and adjacent metal features within the respective metal layers forms a
Conversely, as the via capture pad in
Non-uniform grip pads, as well as other techniques disclosed herein, may also be used in IC devices. For example, fig. 5A may represent a cross-section of an IC device that includes additional active electronic components (not shown, e.g., transistors) configured to implement the desired functionality of the IC (e.g., processing signals from sensors). In some implementations, the
Example LIDAR device with optically isolated PCB
Fig. 7 shows a lateral cross-section of PCB500 assembled with a
Accordingly, the
The PCB500 and the
Example method of manufacturing a PCB with optical isolation
FIG. 8 illustrates an
In
In
Forming the first metal layer and its features may include starting with a metal-clad PCB substrate. Alternatively, an adhesive-backed metal sheet or metal film may be bonded to the PCB substrate. Photoresist may be applied to the metal layer. The photoresist may then be exposed through a mask and subsequently developed (i.e., exposed to ultraviolet light to polymerize the photoresist) to protect the metal regions defining the desired features. The unprotected metal regions may be etched and the protective photoresist may be removed to reveal the metal features.
In
In
In some cases, the entire via may be drilled and filled in one step (e.g., a through-hole via). Alternatively, the vias may be drilled and filled in multiple steps. For example, the stacked micro via may be sequentially built by manufacturing a portion of the stacked micro via each time a metal layer is formed on the PCB substrate. Specifically, the operations of laser drilling, metal deposition, and via filling may be repeated for each metal layer to build up a micro-via stack.
A multi-layer PCB may be manufactured by providing additional PCB substrate layers and depositing additional metal layers thereon. The additional metal layer may include a grip pad of a first size, a second size, or another larger or smaller size, as desired, to block light transmission through the area of the PCB substrate around the via. Additionally, other known PCB fabrication techniques may be used in addition to or in place of those described herein to form PCB layers and features therein. The manufacturing process used may depend on the type of via desired or the dimensions of the PCB components, among other factors.
Conclusion
The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from the scope thereof, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims.
The above detailed description describes various features and functions of the disclosed systems, devices, and methods with reference to the accompanying drawings. The example embodiments described herein and in the drawings are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
The blocks representing information processing may correspond to circuitry that may be configured to perform the particular logical functions of the methods or techniques described herein. Alternatively or additionally, a block representing information processing may correspond to a module, segment, or portion of program code (including related data). The program code may include one or more instructions executable by a processor for implementing specific logical functions or actions in a method or technique. The program code and/or associated data may be stored on any type of computer-readable medium, such as a storage device including a diskette or hard drive or other storage medium.
The computer-readable medium may also include non-transitory computer-readable media, such as computer-readable media that store data for short periods of time, such as register memory, processor cache, and Random Access Memory (RAM). The computer-readable medium may also include, for example, a non-transitory computer-readable medium that stores program code and/or data for longer periods of time, such as a secondary or permanent long-term storage device, e.g., read-only memory (ROM), optical or magnetic disks, compact disk read-only memory (CD-ROM). The computer readable medium may also be any other volatile or non-volatile storage system. For example, the computer-readable medium may be considered a computer-readable storage medium, or a tangible storage device.
Furthermore, a block representing one or more transfers of information may correspond to a transfer of information between software and/or hardware modules in the same physical device. However, other information transfers may occur between software modules and/or hardware modules in different physical devices.
The particular arrangements shown in the drawings should not be considered limiting. It should be understood that other embodiments may include more or less of each element shown in a given figure. Further, some of the illustrated elements may be combined or omitted. Still further, example embodiments may include elements not shown in the figures.
Additionally, any enumeration of elements, blocks or steps in the present description or claims is for clarity. Thus, this enumeration should not be interpreted as requiring or implying that such elements, blocks or steps follow a particular arrangement or are carried out in a particular order.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.
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