Temperature-dependent calibration of a motion detection device

Abstract

To provide calibration of a motion detection device.SOLUTION: An electronic system includes a circuit board 12 having a thermal interface 52 with a surface to be exposed. A thermoelectric device is placed against the thermal interface to heat the board. Heat is transferred through the board from a first region where the thermal interface is located to a second region where an electronic device 14 is installed. The electronic device has a temperature sensor for detecting a temperature of the electronic device. The temperature of the electronic device is used for calibrating an accelerometer and a gyroscope in the electronic device. Calibration data includes a temperature, a corresponding acceleration offset, and a corresponding angular offset. Field computers simultaneously measure the temperature, acceleration, and angle from the temperature sensor, accelerometer, and gyroscope and adjust the measured data using offset data at the same temperature. The field computer provides the corrected data to a control system.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 62 / 702,870, filed July 24, 2018, the entire contents of which are incorporated herein by reference in their entirety.

[0002] 1) Field of the invention The present invention relates generally to electronic systems, methods of building electronic systems, and methods of operating electronic devices, and more particularly to calibrating motion detection devices. [Background technology]

[0003] 2) Discussion of related technologies Electronic devices such as semiconductor chips frequently include motion detection devices such as accelerometers and gyroscopes. An accelerometer can detect the acceleration of an electronic device in a specified direction, and a gyroscope can detect angular changes of the electronic device. Such measurement devices are typically fabricated using microelectromechanical systems (MEMS) technology. Summary of the Invention [Means for solving the problem]

[0004] The present invention provides an electronic system including a board, which may include a structural material, a thermal conduit on the structural material, the thermal conduit having a thermal conductivity higher than that of the structural material and having a first region, a second region, and a connecting portion connecting the first region to the second region, a thermal interface on the structural material, the thermal interface having a thermal heat transfer capacity higher than that of the structural material and attached to the first region of the thermal conduit, and an electronic device mounted to the board at the second region of the thermal conduit, the thermal conduit forming a thermal path between a surface of the thermal interface and the electronic device.

[0005] The present invention also provides a method of constructing an electronic system, including constructing a board, which may include forming a thermal conduit on a structural material, the thermal conduit having a thermal heat transfer capacity higher than that of the structural material and having a first region, a second region, and a connecting portion connecting the first region to the second region; forming a thermal interface on the structural material, the thermal interface having a thermal heat transfer capacity conductivity higher than the thermal heat transfer capacity of the structural material and attached to the first region of the thermal conduit; and mounting an electronic device on the board at the second region of the thermal conduit, the thermal conduit forming a thermal path between a surface of the thermal interface and the electronic device.

[0006] The present invention further provides a method of operating an electronic device, the method including: operating an electronic device mounted on a board; positioning a thermal device adjacent to a thermal interface of the board formed on a structural material of the board; and transferring heat between the thermal device and the electronic device through a thermal conduit on the structural material, the thermal conduit having a thermal heat transfer capacity higher than that of the structural material and having a first region attached to the thermal interface, a second region in the electronic device, and a connecting portion connecting the first region to the second region. The present invention provides, for example, the following items. (Item 1) 1. An electronic system comprising: a board, the board comprising: A structural material; a thermal conduit on the structural material, the thermal conduit having a thermal conductivity higher than that of the structural material, the thermal conduit having a first region, a second region, and a connecting portion connecting the first region to the second region; a thermal interface on the structural material, the thermal interface having a thermal heat transfer capacity greater than a thermal heat transfer capacity of the structural material, the thermal interface being attached to the first region of the thermal conduit; an electronic device mounted on the board at the second region of the thermal conduit, the thermal conduit forming a thermal path between the thermal interface surface and the electronic device; and an electronic system, (Item 2) Item 10. The electronic system of item 1, wherein the heat conduit comprises a metallic conductor. (Item 3) Item 3. The electronic system of item 2, wherein the heat conduit includes at least two metal layers separated by a layer of the structural material. (Item 4) Item 4. The electronic system of item 3, wherein the heat conduit includes at least one metal via interconnecting the layers. (Item 5) Item 5. The electronic system of item 4, wherein the heat conduit includes a plurality of metal vias interconnecting the layers. (Item 6) Item 3. The electronic system of item 2, wherein the metallic conductor is made of a metal that is more thermally conductive than the structural material. (Item 7) Item 3. The electronic system of item 2, wherein the board has at least one metal layer having an inner portion and an outer portion, the structural material forming a barrier between the inner portion and the outer portion, the inner portion forming the thermal conduit, and the thermal interface and the electronic device located on the inner portion. (Item 8) Item 8. The electronic system of item 7, wherein the metal layer is more conductive than the structural material. (Item 9) Item 8. The electronic system of item 7, wherein the structural material forms a plurality of barriers between the inner portion and the outer portion, the barriers alternating with portions of the metal layer interconnecting the inner portions. (Item 10) a motion detection device within the electronic device; a system storage device; Calibration data on the system storage device, the calibration data comprising: a first temperature of the motion detection device; a first output from the movement detection device recorded versus the first temperature; a second temperature of the motion detection device that is different from the first temperature; and a second output from the movement detection device recorded versus the second temperature; and Calibration data, including Item 1. The electronic system of item 1, further comprising: (Item 11) Item 11. The electronic system of item 10, wherein the movement detection device is an accelerometer. (Item 12) Item 11. The electronic system of item 10, wherein the movement detection device is a gyroscope. (Item 13) Item 11. The electronic system of item 10, further comprising a temperature detector within the electronic device. (Item 14) On-site computers and an interface connecting the on-site computer to the movement detection device and the temperature detector; a control system connected to said on-site computer; Item 14. The electronic system of item 13, further comprising: (Item 15) 1. A method of constructing an electronic system, comprising: constructing a board, said constructing the board comprising: forming a thermal conduit on the structural material, the thermal conduit having a thermal heat transfer capacity higher than a thermal heat transfer capacity of the structural material, the thermal conduit having a first region, a second region, and a connecting portion connecting the first region to the second region; forming a thermal interface on the structural material, the thermal interface having a thermal heat transfer capacity conductivity higher than a thermal heat transfer capacity of the structural material, the thermal interface being attached to the first region of the thermal conduit; Mounting an electronic device on the board at the second region of the thermal conduit, the thermal conduit forming a thermal path between the thermal interface surface and the electronic device; A method comprising: (Item 16) 1. A method of operating an electronic device, comprising: operating an electronic device mounted on the board; positioning a thermal device adjacent a thermal interface of the board, the thermal device being formed on a structural material of the board; transferring heat between the thermal device and the electronic device through a thermal conduit on the structural material, the thermal conduit having a thermal heat transfer capacity higher than a thermal heat transfer capacity of the structural material, the thermal conduit having a first region attached to the thermal interface, a second region on the electronic device, and a connecting portion connecting the first region to the second region; A method comprising: (Item 17) and further comprising calibrating a movement detection device in the electronic device that detects movement while transferring the heat, the calibrating the device comprising: Detecting a first temperature of the movement detection device; detecting a first output from the movement detection device; calculating a first offset based on the first output and a first baseline output; recording the first temperature and the first offset; changing the temperature of the motion detection device from the first temperature to a second temperature; Detecting the second temperature of the motion detection device; and detecting a second output from the movement detection device; calculating a second offset based on the second output and a second baseline output; recording the second temperature and the second offset; Item 17. The method according to item 16, comprising: (Item 18) Item 17. The method of item 16, further comprising removing the thermal device from the thermal interface after the calibration of the movement detection device.

[0007] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a top view in a first plane of an electronic system according to one embodiment of the present invention.

[0009] [Figure 2] FIG. 2 is a cross-sectional side view of the electronic system in a second plane on 2-2 of FIG.

[0010] [Figure 3] FIG. 3 is a cross-sectional side view of the electronic system in a third plane on 3-3 of FIG.

[0011] [Figure 4] FIG. 4 is a side view similar to FIG. 1, further illustrating an electronic device forming part of the electronic system.

[0012] [Figure 5] FIG. 5 is a cross-sectional side view taken on line 5-5 of FIG. 4, showing an enlarged detailed view of the electronic device.

[0013] [Figure 6] FIG. 6 is a cross-sectional side view of the electronic system further illustrating the calibration station.

[0014] [Figure 7] FIG. 7 is a cross-sectional side view of an electronic system further illustrating the use of a calibration station to heat and calibrate electronic devices of the electronic system.

[0015] [Figure 8] FIG. 8 is a cross-sectional side view of the electronic system further showing the on-site computer and control system that uses the calibration data.

[0016] [Figure 9] FIG. 9 is a cross-sectional side view of an electronic system according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] (Detailed Description of the Invention) Output readings from motion detection devices such as accelerometers and gyroscopes can be affected by changes in the device's temperature, resulting in temperature-dependent errors in the output measurements. For example, an accelerometer in a stationary state should provide an output measurement corresponding to gravitational acceleration; however, when the accelerometer is subjected to a different temperature, the output measurement will differ due to errors associated with the accelerometer being at a higher temperature. Because the output should not change while the accelerometer is stationary—i.e., acceleration is still simply gravity, regardless of temperature—it is possible to isolate output measurement errors associated with temperature by finding the difference (i.e., "offset") between the erroneous measurement and a known baseline measurement (gravity, in the case of an accelerometer). By performing this measurement comparison at multiple temperatures, many data points can be collected and an offset profile over a range of temperatures can be obtained. A set of data associating temperature with specific offset readings can be compiled for each motion detection device during the calibration process. The data can be stored as calibration data in a table for lookup or extrapolation, or used to define a best-fit function. The calibration data can be accessed by a virtual reality, augmented reality, or mixed reality system to obtain adjusted measurements from the movement detection device given the temperature of the movement detection device and its initial "raw" measurements.

[0018] A calibration system and a process for improving the accuracy of the calibration are described herein. Known methods for calibrating a motion detection device involve contacting the motion detection device with a temperature probe and introducing heat through conduction, or require actively blowing air across the motion detection device to adjust its temperature through convection. Both of these methods may cause the device to move such that measurements obtained from the device during calibration will include errors associated with temperature and errors associated with movement introduced by the measurement method. Because it is impossible to know the amount of movement introduced by the measurement method, it is impossible to isolate the errors associated with temperature. As a result, the errors cannot be accurately removed from the raw output measurements of the device. In virtual, augmented, and mixed reality systems, the accuracy of measurements obtained by the device is important for determining where to display virtual content to a user relative to movement between the user and a real or virtual environment. Therefore, there is a need for highly accurate calibration systems and methods in virtual, augmented, or mixed reality devices.

[0019] 1, 2, and 3 illustrate an electronic system 10 according to an embodiment of the present disclosure. FIG. 1 is a top view of an exemplary configuration of a board 12 within the electronic system 10. FIG. 2 is a cross-sectional side view taken along line 2-2 of FIG. 1. FIG. 3 is a cross-sectional side view taken along line 3-3 of FIG. 1. The electronic system 10 includes a board 12 constructed from multiple layers of different materials. The layers and various features disposed therein provide specific functionality during calibration and use of an electronic device 14, such as a sensor or sensor suite (discussed with respect to FIGS. 4 and 5), connected to the board 12.

[0020] The board 12 is constructed from a structural material 22, such as an FR4 dielectric, and a thermally and electrically conductive material, such as a metal component 24. The metal component 24 may include a copper material. The metal of the metal component 24 is more thermally conductive than the structural material 22, and therefore has a higher thermal heat transfer capacity. The metal of the metal component 24 is electrically conductive, while the structural material 22 is electrically insulating.

[0021] Multiple layers of structural material 22 can be included within board 12. As shown in the example of Figures 2 and 3, two structural layers 28 and 30 can be provided. Metal components 24 are disposed between the layers of structural material 22. For example, metal components 24 can include first, second, and third metal layers 34, 36, and 38 separated by first and second structural layers 28 and 30. Board 12 further includes top and bottom insulating layers 32 and 26 covering first and third metal layers 34 and 38. Top and bottom insulating layers 32 and 26 can include an electrically insulating solder resist material 25.

[0022] Metal component 24 also includes first and second sets of vias 40 and 42, respectively. First set of vias 40 connect a portion of first metal layer 34 to a portion of second metal layer 36. Second set of vias 42 connect a portion of second metal layer 36 to a portion of third metal layer 38. Metal layers 34, 36, and 38 are thereby electrically and thermally connected to one another. Metal layers 34, 36, and 38, together with first and second sets of vias 40 and 42, form a thermal conduit of thermally conductive material connecting first region 46 of the thermal conduit to second region 48 of the thermal conduit.

[0023] Portions of the third metal layer 38 are isolated as metal lines 76 to function as traces for electrical signals. These metal lines 76 can be isolated from each other and from the other metal components 24 such that each line is surrounded by a non-conductive material, such as the dielectric structural material 22 and the insulating solder-resist material 25. Those skilled in the art will appreciate that more or fewer than three metal lines 76 can be provided depending on the design of the electronic device 14 mounted to the board 12 in the second region 48. The metal lines 76 can be disposed in one or more of the metal layers within the board 12. Additionally, although the lines 76 are shown as exposed portions of the metal components 24, portions of the metal lines 76 can also be coated with the insulating solder-resist material 25.

[0024] Metal component 24 further includes thermal interface 52. Thermal interface 52 is the area of ​​third metal layer 38 in first region 46 that is exposed by removing a portion of upper insulating layer 32. Thermal interface 52 is an upper surface 54 of third metal layer 38 that is exposed and configured to contact a portion of electronic device calibration station 80. Upper surface 54 forms only a portion of the upper surface of board 12, with the remainder of the upper surface consisting of structural layer 30 and the upper surface of insulating solder resist layer 32.

[0025] 1 and 2 , the first, second, and third metal layers 34, 36, 38 have an inner portion 58 and an outer portion 60. The structural material 22 forms a plurality of barriers 62 that separate the inner portion 58 from the outer portion 60. The barriers 62 act as thermal barriers to prevent, or at least substantially slow down, heat transfer from the inner portion 58 to the outer portion 60 of the second metal layer 36 so that the outer portion 60 remains cooler than the inner portion 58. Additional electronic components may be connected to the board 12. Such components may be connected to the board 12 at the outer portion 60 to keep the components from experiencing high heat during the calibration process.

[0026] 1 and 3 in combination, it can be seen that the first, second, and third metal layers 34, 36, 38 also have connecting portions 64 that connect the inner portion 58 to the outer portion 60. The connecting portions 64 ensure that the metal layers are electrically grounded such that an equal reference voltage exists between the inner portion 58 and the outer portion 60.

[0027] 1 and 2 in combination, it can be seen that similar thermal barriers 62 are formed at one or more locations within the first, second, and third metal layers 34, 36, and 38 (FIG. 1), and that each metal layer has a separate portion 64 connecting its inner and outer regions. The barriers 62 prevent, or at least slow, heat transfer from the inner portion 58 to the outer portion 60, protecting other components attached to the board 12 from experiencing high temperatures during calibration of the electronic device 14.

[0028] 4 and 5, electronic system 10 further includes electronic device 14 and system storage 18. Electronic device 14 is mounted to the upper surface of board 12 through connections 74. Electronic device 14 and thermal interface 52 reside within barrier 62, which defines interior portion 58. Electronic device 14 is mounted above second region 48 of the thermal conduit described above.

[0029] The electronic system 10 further includes a board interface 16 mounted on the board 12 and connected to measurement devices within the electronic device 14. The electronic device 14 includes a structural body 66 and several measurement devices within the structural body 66. The measurement devices include a temperature sensor 68 and two motion detection devices in the form of an accelerometer 70 and a gyroscope 72. While two motion detection devices are used for purposes of this embodiment, it may be possible to implement aspects of the present invention using only one measurement device. For example, it may be possible to calibrate an electronic device having only a gyroscope or only an accelerometer. The structural body 66 may be, for example, a silicon or other semiconductor structural body that may be packaged using conventional packaging techniques. The temperature sensor 68, accelerometer 70, and gyroscope 72 are connected to the board interface 16 through connectors 74 on the upper surface of the board 12 and metal lines 76 within the board 12. Data traces from the temperature sensor 68, accelerometer 70, and gyroscope 72 are routed to a microprocessor 73 within the structural body 66, which serves as an input / output interface for the measurement devices. The system storage 18 serves to store calibration data received from the calibration station 80 associated with the accelerometer 70 and gyroscope 72. The system storage 18 may include, for example, solid-state memory. While the system storage 18 is shown near the electronic device 14, the system storage may be a cloud-based storage device or a remote storage device located on another area of ​​the electronic device so as not to contact the board 12. Those skilled in the art will appreciate that the system storage 18 may be located anywhere that communicates with the electronic device 14 and enables data transfer between the electronic device 14 and the system storage 18. The system storage 18 does not contain calibration data immediately after the electronic system 10 is assembled (i.e., prior to undergoing calibration), but is uniquely associated with the electronic device 14 by allowing data to be transferred between the electronic device 14 and the system storage 18.

[0030] FIG. 6 further illustrates a calibration station 80 used to calibrate the accelerometer 70 and the gyroscope 72. The calibration station 80 includes a frame 82, a calibration computer 84, a calibration computer interface 86, a thermoelectric device 88, a transformer 90, and a power connector 92. The components of the calibration station 80 are mounted in a fixed position relative to one another via the frame 82. The spacing between the calibration computer interface 86 and the thermoelectric device 88 is the same as the spacing between the board interface 16 and the thermal interface 52. The calibration computer 84 is connected to the calibration computer interface 86 so that signals can be transmitted between the calibration computer 84 and the calibration computer interface 86. Information from the microprocessor 73 can be accessed by the calibration station 80. The calibration computer 84 is connected to a power connector 92 so that power can be supplied to the calibration computer 84 through the power connector 92. The thermoelectric device 88 is connected to the power connector 92 through the transformer 90. Power can be provided to the thermoelectric device 88 through a transformer 90 by a power connector 92. The transformer 90 reduces the voltage provided by the power connector 92 before providing power to the thermoelectric device 88. The thermoelectric device 88 is preferably a reversible heat pump, such as a thermoelectric cooler, that can provide heat into or extract heat from the board 12. The flexibility to achieve a wide range of temperatures on the board 12, and therefore the electronic device 14, can improve the accuracy of calibration of the electronic device 14.

[0031] In use, the electronic system 10 is brought into contact with a portion of the calibration station 80. As the electronic system 10 and the calibration station 80 move relatively toward one another, the calibration computer interface 86 connects to the board interface 16 and can begin receiving data from the electronic device 14 simultaneously with the thermoelectric device 88 contacting the thermal interface 52. In the described embodiment, the calibration computer interface 86 and the board interface 16 are wired interfaces that can contact each other to create a communication link and release from each other to break the communication link. Data is received through wired communication between the electronic system 10 and the calibration station 80. In another embodiment, the calibration station 80 and the board can include a wireless interface that creates a wireless link for data transfer, which is then broken.

[0032] Electrical power, which powers the calibration computer 84, is provided to the calibration computer 84 through a power connector 92. Power is also provided to the thermoelectric device 88 through the power connector 92 and a transformer 90.

[0033] The entire electronic system 10 may initially begin calibration at room temperature, e.g., about 21° C. The temperature sensor 68 (FIG. 5) provides a temperature output to the calibration computer 84. The accelerometer 70 and gyroscope 72 simultaneously provide outputs to the calibration computer 84 that are related to the output temperature from the temperature sensor 68. Baseline outputs for the accelerometer and gyroscope are either known as the device is at rest, or are established at a reference temperature, such as room temperature. These baseline outputs are used later in the calibration process to isolate errors in the measurements (“offsets”) associated with temperature changes in the sensors.

[0034] 7 illustrates that calibration computer 84 is connected to system storage 18 and records calibration data 96 in system storage 18 as calibration offsets are calculated. The initial entry in the table of calibration data 96 includes an initial temperature (21° C. in this example), an acceleration offset (calculated by finding the difference between the acceleration measurement at each temperature and the known acceleration), and an angular offset (calculated by finding the difference between the gyroscope measurement at each temperature and the known position information), each calculated with respect to the temperature sensor measurements determined using inputs from accelerometer 70 and gyroscope 72.

[0035] The thermoelectric device 88 has an upper surface that is cooler than room temperature and a lower surface that is warmer than room temperature. Heat is transferred from the hot lower surface of the thermoelectric device 88 through the upper surface 54 of the thermal interface 52 and into the thermal interface 52. The heat transfer is primarily via conduction. The heat then conducts through the third metal layer 38 and the first and second sets of vias 40 and 42 to the first and second metal layers 34 and 36. The heat then conducts outward from the first region 46 closest to the heat source through the first, second, and third metal layers 34, 36, and 38 toward the second region 48. The barrier 62 prevents, or at least substantially slows, the transfer of heat from the inner portion 58 to the outer portion 60.

[0036] Heating the second region 48 increases its temperature. While heat conduction through the metal layers 34, 36, 38 and thermal vias 40, 42 occurs rapidly, significantly slower heat conduction occurs within the structural material layers 28, 30. Conduction through the upper metal layer 38 evenly distributes heat beneath the electronic device 14 within the second region 48. The increased temperature in the second region 48 causes heat transfer through conduction via the connections 74 and through passive convection of the air surrounding the electronic device 14. This method of heating the electronic device 14 closely mimics field conditions the electronic device 14 would experience. The temperature sensor 68 continues to detect the temperature of the electronic device 14. The calibration computer 84 samples the temperature of the temperature sensor 68 at predetermined intervals, for example, every 5 seconds or more frequently, for improved accuracy. Calibration computer 84 also samples the outputs from accelerometer 70 and gyroscope 72 at the same time that calibration computer 84 samples the temperature from temperature sensor 68. Calibration computer 84 then calculates and stores each temperature, and each acceleration offset, and each angular offset using calibration data 96. As explained previously herein, each temperature is associated with an acceleration offset and an angular offset component in the measurement readings of the accelerometer and gyroscope, respectively. An offset profile can be obtained by measuring the output of each sensor across a range of temperatures, subtracting the known value the sensor should measure each time from the actual measurement, and calculating the error. Each temperature therefore has a different acceleration offset and angular offset associated with it, even if accelerometer 70 and gyroscope 72 remain steady from one measurement to the next. In some embodiments, multiple measurements are taken at each temperature, and an average offset is calculated for improved accuracy.

[0037] Once sufficient data has been collected, the calibration station 80 is removed from contact with the board 12. The calibration computer interface 86 writes the collected calibration data to the system memory 18 and disconnects from the board interface 16. The thermoelectric device 88 disengages from the thermal interface 52. Heat is convected and conducted away from the electronic device 14 until the entire electronic device 14 returns to room temperature.

[0038] The calibration system and process described above does not require physical contact between the calibration station and the electronic device 14, nor does it require forced convection across the electronic device 14. Rather, the electronic device 14 is heated via conduction through the permanent connections to the board 12 (connectors 74 and metal lines 76) and via passive convection, without the need for additional probe contact with or forced air blowing across the electronic device 14. The electronic device 14 can therefore be calibrated for temperature without disturbing the accelerometers 70 or gyroscopes 72. The system and process allows for more accurate offset calibration while mimicking actual field conditions for sensors on the board electronic device 14.

[0039] 8 illustrates the electronics system, including a field computer 100, a field computer interface 102, and a control system 104. The control system 104 may be, for example, a virtual reality, augmented reality, or mixed reality device. The field computer 100 is connected to the field computer interface 102. The control system 104 is connected to the field computer 100. The field computer 100 may be, for example, a computer that processes movement data for an augmented reality vision system, and the control system 104 may be the vision processing system for a vision device. The field computer 100 is connected to the system storage 18 and has access to the calibration data 96.

[0040] In use, the electronic system 10 is moved, for example, linearly or rotationally. The accelerometer 70 and gyroscope 72 detect such movement of the electronic system 10. The on-site computer 100 senses signals received from the temperature sensor 68, the accelerometer 70, and the gyroscope 72. The on-site computer 100 uses the temperature detected from the temperature sensor 68 to find a corresponding temperature in the calibration data 96. The calibration data 96 may include a table with data as described above, or may include a formula, such as a linear regression, that represents the calibration data. The on-site computer 100 reads the acceleration offset and angle offset in the calibration data 96 that correspond to the temperature measured by the temperature sensor 68. The on-site computer 100 then adjusts the acceleration detected by the accelerometer 70 by the acceleration offset (acceleration = measured acceleration - acceleration offset). The on-site computer 100 also adjusts the angle measured by the gyroscope 72 by an angle offset corresponding to the temperature (adjusted angle = measured angle - angle offset). The on-site computer 100 then provides the adjusted acceleration and the adjusted angle to the control system 104. The control system 104 utilizes the adjusted acceleration and the adjusted angle in one or more formulas. As an example, the control system 104 adjusts the placement of a rendered image in an augmented reality or mixed reality viewing device according to a placement formula that uses the adjusted acceleration and adjusted angle received from the on-site computer 100.

[0041] FIG. 9 illustrates an alternative embodiment in which the thermal conduit is provided by any known heat spreader that may be integrated into the chip. In some embodiments, the heat spreader can be a heat pipe 110. The heat pipe 110 has an evaporator end 112 and a condenser end 114. The evaporator end 112 is located at or in close proximity to the thermal interface 52, and the condenser end 114 is located in close proximity to the electronic device 14. In use, the thermal interface 52 heats the liquid within the heat pipe 110, causing it to evaporate. The resulting vapor flows from the evaporator end 112 to the condenser end 114 and condenses. The resulting condensed liquid then flows from the condenser end 114 back to the evaporator end 112 through a capillary transport system.

[0042] FIGS. 1-8 illustrate one type of thermal conduit made of a thermally conductive metal. The design of FIGS. 1-8 is relatively inexpensive to manufacture. FIG. 9 illustrates a different type of thermal conduit in the form of a heat pipe. Heat pipes can transfer more heat through flow than thermally conductive metals, but can be more expensive to manufacture. The thermal conduit provided by the thermally conductive metal of FIGS. 1-8 and the thermal conduit provided by the heat pipe of FIG. 9 both have a thermal heat transfer capacity that is higher than the thermal heat transfer capacity of the structural material 22 of the board 12, and both form a thermal path between the surface of the thermal interface 52 and the electronic device 14.

[0043] While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are illustrative only and do not limit the invention, and that the invention is not limited to the specific constructions and arrangements shown and described, as modifications may occur to those skilled in the art.

Claims

1. 1. An electronic system comprising: A board, the board comprising: A structural material; a thermal conduit on the structural material, the thermal conduit having a thermal conductivity higher than that of the structural material, the thermal conduit having a first region, a second region, and a connecting portion connecting the first region to the second region, the first region and the second region being horizontally spaced apart; a thermal interface on the structural material above the first region of the heat conduit, the thermal interface having an exposed upper surface and a thermal heat transfer capacity higher than a thermal heat transfer capacity of the structural material, the thermal interface being attached to the first region of the heat conduit; a board including: an electronic device mounted on the board above the second region of the thermal conduit, the thermal conduit forming a thermal path between the surface of the thermal interface and the electronic device; and a board interface mounted on the board and electrically connected to the electronic device, the board interface adapted to interchangeably connect to a calibration computer interface of a calibration station having a thermoelectric device for releasably contacting the exposed upper surface, the board interface adapted to connect to a field computer interface connected to a field computer; An electronic system comprising:

2. The electronic system of claim 1 , wherein the thermal conduit comprises a metallic conductor.

3. The electronic system of claim 2 , wherein the thermal conduit comprises at least two metal layers separated by a layer of the structural material.

4. The electronic system of claim 3 , wherein the thermal conduit includes at least one metal via interconnecting the layers.

5. The electronic system of claim 4 , wherein the thermal conduit comprises a plurality of metal vias interconnecting the layers.

6. The electronic system of claim 2 , wherein the metallic conductor is made from a metal that is more thermally conductive than the structural material.

7. 3. The electronic system of claim 2, wherein the board has at least one metal layer having an inner portion and an outer portion, the structural material forming a barrier between the inner portion and the outer portion, the inner portion forming the thermal conduit, and the thermal interface and the electronic device located on the inner portion.

8. The electronic system of claim 7 , wherein the metal layer is more conductive than the structural material.

9. 8. The electronic system of claim 7, wherein the structural material forms a plurality of barriers between the inner and outer portions, the barriers alternating with portions of the metal layer interconnecting the inner portions.

10. a motion detection device within the electronic device; a system storage device; Calibration data on the system storage device, the calibration data comprising: a first temperature of the motion detection device; a first output from the movement detection device recorded versus the first temperature; a second temperature of the motion detection device different from the first temperature; a second output from the movement detection device recorded relative to the second temperature; and Calibration data, including The electronic system of claim 1 further comprising:

11. The electronic system of claim 10 , wherein the motion detection device is an accelerometer.

12. The electronic system of claim 10 , wherein the motion detection device is a gyroscope.

13. The electronic system of claim 10 further comprising a temperature detector within the electronic device.

14. On-site computers and an interface connecting the on-site computer to the movement detection device and the temperature detector; a control system connected to said on-site computer; The electronic system of claim 13 further comprising:

15. 1. A method of constructing an electronic system, comprising: constructing a board, the board comprising a structural material, forming a thermal conduit on the structural material, the thermal conduit having a thermal heat transfer capacity higher than a thermal heat transfer capacity of the structural material, the thermal conduit having a first region, a second region, and a connecting portion connecting the first region to the second region, the first region and the second region being horizontally spaced apart; forming a thermal interface on the structural material above the first region of the thermal conduit, the thermal interface having an exposed upper surface and a thermal heat transfer capacity conductivity higher than the thermal heat transfer capacity of the structural material, the thermal interface being attached to the first region of the thermal conduit; Mounting an electronic device on the board above the second region of the thermal conduit, the thermal conduit forming a thermal path between the surface of the thermal interface and the electronic device; attaching a board interface to the board, the board interface electrically connected to the electronic device, the board interface adapted to replaceably connect to a calibration computer interface of a calibration station having a thermoelectric device for releasably contacting the exposed upper surface, the board interface adapted to connect to a field computer interface connected to a field computer; A method comprising:

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