Patent Publication Number: US-2019182994-A1

Title: Head up display cooling

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/598,157, filed on Dec. 13, 2017, which the disclosure of which is hereby incorporated by reference in its entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure generally relates to a method, system, and device for cooling a Head Up Display (HUD) in a vehicle. More specifically, the present disclosure relates to cooling a HUD with an attached heatsink and an outlet in a nearby Heating and Ventilation Air Conditioning duct to direct air towards and through the heatsink. 
     BACKGROUND 
     This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it can be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Vehicles, such as automobiles may utilize a Head Up Display (HUD) to alert a driver or passenger of relevant information, navigational directions, warnings, entertainment, or other light based features. The generation of light can include generation of heat energy. 
     SUMMARY 
     This specification generally discloses a HUD cooling system, method and device. In an example, the vehicle head up display cooling system can include a head up display module to emit light with a Picture Generation Unit (PGU). The system may also include a heatsink attached to the HUD module to draw heat from the PGU through conduction and dissipate heat through convection. The system includes a Heating, Ventilation, and Air Conditioning (HVAC) duct with an outlet to direct airflow from the HVAC duct towards the heatsink. 
     An example method for cooling a HUD in a vehicle, includes emitting light with a PGU of a HUD module. The method may also draw heat from the PGU through conduction by contact of a heatsink to the PGU, where the heatsink is attached to the HUD module and dissipates heat through convection. The example method may also direct airflow from an HVAC duct towards the heatsink, the airflow directed by an outlet on the HVAC duct. 
     A device for HUD cooling includes a head up display HUD module to emit light with a PGU. The device may include a heatsink attached to the HUD module to draw heat from the PGU through conduction and dissipate heat through convection. The device may include a HVAC duct with an outlet to direct airflow from the HVAC duct towards the heatsink. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of the present disclosure, and the manner of attaining them, may become apparent and be better understood by reference to the following description of one example of the disclosure in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a schematic of an example head up display cooling system; 
         FIG. 2  is a drawing of airflow through an HVAC outlet and heatsink; 
         FIG. 3  is a schematic of an example HUD cooling device with a temperature sensor and valve on the HVAC outlet; 
         FIG. 4  is a process flow diagram of an example method for cooling a HUD; and 
         FIG. 5  is a drawing of an example computer-readable medium storing instructions, that when executed on a processor cools a HUD through control of an HVAC outlet valve. 
     
    
    
     Correlating reference characters indicate correlating parts throughout the several views. The exemplifications set out herein illustrate examples of the disclosure, in one form, and such exemplifications are not to be construed as limiting in any manner the scope of the disclosure. 
     DETAILED DESCRIPTION OF EXAMPLES 
     In an effort to provide a concise description of these examples, not all features of an actual implementation are described in the specification. It can be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it can be appreciated that such a development effort might be complex and time consuming, and is a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     The present disclosure describes cooling for Head Up Displays (HUDs) through increased airflow within the instrument panel. HUDs include light emitting components that generate heat that is trapped within the enclosed space of the dashboard of a vehicle. The more heat is generated the light emitting sources of the HUD, the more heat that builds up. Rather than increase the size of a heatsink in an already crowded instrument panel area, the present disclosure relates to making use of a nearby Heating, Ventilation and Air Conditioning (HVAC) duct for airflow. By adding an outlet to the HVAC duct, the HUD can increase airflow and heat dissipation through the heatsink. By increasing airflow, the size of the heatsink can be decreased while still dissipating the same amount of heat or more. The addition of an outlet on the HVAC duct means that no moving parts such as fans are needed to generate air movement. The present disclosure relates to a solution that increases heat dissipation while reducing the amount of space occupied by the heatsink in the instrument panel. 
       FIG. 1  is a schematic of an example head up display cooling system  100 . Directional arrows located in this figure indicate a general airflow or movement of air unless the arrow is pointing directly to an object such as the fins of the heatsink. 
     The HUD cooling system  100  is housed within an instrument panel  102  of a vehicle. The instrument panel can include displays, electronics, ventilation, and other user interfaces with both the operation of the vehicle and with electronic features used for navigation, temperature control, entertainment and similar activities. The instrument panel may include a Head Up Display (HUD)  104 . The HUD  104  may include alerts, warnings, speeds, temperature gauges, odometers, estimated times of arrival, a back-up camera display, and other pictures, numbers, and information about the vehicle, location of the car, user information, and the like. The information displayed on the HUD  104  can be displayed with a Picture Generation Unit (PGU)  106  which can be a light display based on a number of technologies. In an example, the PGU  106  can include a Liquid Crystal Display (LCD), an LCD display with Light Emitting Diodes (LEDs) behind the LCD display to increase visibility, a Digital Kight Processing (DLP) display, and other light emitting displays. 
     To improve heat dissipation, the HUD  104  can include a heatsink  108  that is attached to the HUD  104  or the PGU  106  itself. The heatsink  108  can be a passive heat exchanger that transfers the heat from the PGU  106  to the air within the instrument panel  102 . In an example, the heatsink  108  may be a molded or shaped material, metal, aluminum alloy, copper, or other materials with a thermal conductivity utility. The heatsink may be molded or shaped to have a number of protrusions on one end called fins  110 . The fins  110  in  FIG. 1  are shown from above and are shown to be parallel to each other although other configurations and shapes are possible. For example, the fins could be curved. The fins may be elongated protrusions that increase the surface area of the heatsink  108  to the surrounding air for increase rate of heat transfer from the PGU  106  to the air within the instrument panel  102 . 
     Due to the heat generated by the light emitters of the PGU  106 , the PGU  106  can be a large source of heat within the HUD  104  and the instrument panel  102 . In a closed or semi-closed space like the instrument panel  102 , heat generation can lead to degrading the quality and function of components over time. To increase heat dissipation without increasing the size of the heatsink  108 , the HUD cooling system  100  includes a Heating and Ventilation Air Conditioning (HVAC) duct  112  with an outlet  114  to direct airflow towards the heatsink  108 . The HVAC duct  112  in  FIG. 1  is shown as s discrete unit, however, in practice it may be tubing, piping, or a channel for air moving through the vehicle to heat or cool the interior for drivers and passengers. Whether the air in the HVAC duct is heated or cooled for human comfort, the temperature range of the air moving in the HVAC duct  112  is likely to be cooler than the PGU  106  and heatsink  108  and accordingly, the air moving over across the fins  110  can pull heat away from the heatsink  108 , PGU  106 , and HUD  104 . 
     To direct the airflow from the HVAC duct to across and through the fins  110  of the heatsink  108 , the HVAC duct  112  can include an outlet  114 . The outlet  114  can be positioned such that it creates an opening for air movement to pass in a direction parallel or approximately parallel to the fins  110  of the heatsink  108 . The movement of air through the fins increases the heat dissipation and speed of heat transfer as the moving air more quickly carries away hot air and exposes the fins to newer, likely colder air. The outlet  114  can be an opening made in the HVAC duct  112  at a determined location. In an example, the outlet  114  may also be a physical attachment that includes directional opening to steer the air more specifically towards the heatsink  108 . In an example, the outlet can include an airflow collecting protrusion into tie HVAC duct  112  that effectively redirects moving air from its usual path out from the HVAC duct towards the heatsink  108 . Due to the airflow increasing the heat dispersion rate, the heatsink may be smaller than if the air in the instrument panel  102  were stagnant. Further, the use of an outlet to redirect some of the air from an HVAC duct creates moving air across the heatsink  108  without using moving parts, such as a fan, to generate airflow inside the instrument panel  102 . 
       FIG. 2  is a drawing of airflow  200  through an HVAC outlet  114  and heatsink  108 . Like numbered items are as disclosed above with respect to  FIG. 1 . As above, the arrows shown represent one possible direction of airflow. 
       FIG. 2  shows a zoomed-in perspective of the heatsink  108  to show how the outlet  114  may direct airflow  200  to move through the fins  110 . The position of the airflow  200  may be determined by the location of the outlet  114  as well as the angle of the outlet  114 . In an example, the position of the outlet  114  may steer the airflow  200  both parallel to the direction of the fins  110 . In an example, the outlet may also be located so that the airflow  200  passes through the channels between the fins  110 . While other shapes and configurations of heatsinks  108  and fins  110  is possible, the straight and parallel configuration exposes an increased surface area to the air and creates a path for air to travel both against the fins  110  and the away from the heatsink  108 . 
       FIG. 3  is a schematic of an example HUD cooling device  300  with a temperature sensor and valve on the HVAC outlet. Like numbered items are as disclosed with respect to Fig,  1 . Directional arrows in this figure indicate a general airflow or movement of air unless the arrow is pointing directly to an object such as the tins of the heatsink. Further, although no arrows are here shown for airflow out of the outlet  114 , this is for convenience to allow other elements of this figure to be seen more clearly. As with the other figures, these drawings are simplified versions and omit many components, connections, or elements such as electrical wiring, display screens, user interfaces, and structural details that may distract from the disclosed techniques. 
     In  FIG. 3 , the PGU  106  includes a temperature sensor  302 . The temperature sensor  302  can be analog or digital. In an example, the temperature sensor  302  can be a thermistor or other temperature sensing hardware. In an example, the PGU  106  may include the temperature sensor  302  as well as a subcomponent of the PGU  106 , such as an LED or display of the PGU  106 . The temperature sensor  302  may also be included and attached to the heatsink  108  itself rather than the PGU  106  as shown in the figure. The PGU  106  or HUD  104  may avoid damage and degradation by keeping their temperature at a specified temperature or within a specified temperature range. 
     The HUD cooling device  300  may include a movable valve that alternately covers and uncovers the outlet  114 . In an example the valve may be attached on one end of the periphery of the outlet opening and slide off of the outlet opening or onto the outlet opening depending on the temperature. The valve may be attached at two or more points or broken into multiple pieces and opened in a swinging-out motion or swinging in motion like doors that open or split in the middle. Many other valve designs and configurations are contemplated that could control the amount and direction of airflow from the HVAC duct  112  towards the heatsink  108 . 
     In  FIG. 3 , a valve is shown that is a pivoting disk or pivoting flap shape where the valve may include protrusions in the middle of the valve to allow the valve to pivot both open and closed. To illustrate this example valve.  FIG. 3  shows the valve in the open position  304  and the valve in the closed position  306 . The valve may open and close through rotation movement and may either complete a full rotation to open and close or the valve may reverse its movement direction to alternate between an open and closed position. The amount the valve opens may increase the airflow and accordingly the rate of heat dissipation in the heatsink  108 . 
     In an example, the temperature sensor  302  may detect that a temperature has exceeded a specified temperature or upper bound of a specified temperature range. In response to the detection by the temperature sensor  302 , the valve may move to he the valve in the open position  304 . In response to a detection by the temperature sensor  302 , the valve may move to he the valve in the closed position  306  to decrease airflow when the temperature is detected to he below a specified temperature or lower bound of a specified temperature range. Additionally, the valve may he adjusted incrementally to be fractionally in an open or closed position in response to a detection of temperature by the temperature sensor. For example, the valve may reach an open position based proportionally on where in a temperature range the temperature sensor detects the temperature of the HUD. For example, the bottom of the specified temperature range may correspond to a zero percent valve open position (i.e. a closed position) and the top of the specified temperature range may correspond to a one-hundred percent open valve position. With this example temperature and valve correspondence, each temperature detection can identify a corresponding degree or percentage of valve openness to match how close to measured temperature in the PGU  106  may be to the top of the specified temperature range. In this way, the valve may dynamically respond to produce additional airflow and heat dispersion ability along the heatsink  108  based on a potentially changing temperature measured by the temperature sensor  108 . 
     The valve opening may be controlled by a microprocessor stored in a main board of the HUD  104 . A wire for transmitting control signals and motor, such as a servo motor, may connect the HUD  104  and the valve to allow varying movements and control. The temperature sensor  302  may provide the HUD  104  an analog or digital temperature reading that can be processed to determine a valve position. 
       FIG. 4  is a process flow diagram of an example method for cooling a HUD. While the blocks are shown in a specified order, one or more blocks may change in order based on a particular environment of implementation. 
     At block  402 , the PGU emits light with a Picture Generation Unit (PGU) of a HUD module. In an example, the PGU includes light emitting diodes. At block  408 , a heatsink to the PGU draws heat from the PGU through conduction by contact with the PGU where the heatsink is attached to the HUD module and dissipates heat through convection. In an example, the heatsink comprises a plurality of fins for heat dissipation that are formed in parallel formation along the heatsink. In an example, the heatsink has a flat surface contacting the PGU and an opposite side of the heatsink shaped to form a plurality of fin shaped protrusions. The heatsink may be attached to the PGU at an orientation that enables airflow directed by the outlet to run between the plurality of fin shaped protrusions of the heatsink. The plurality of fin shaped protrusions may be curved so that airflow directed through the plurality of fin shaped protrusions is directed away from the HUD and the outlet of the HVAC duct. 
     At block  410 , an outlet on a Heating, Ventilation, and Air Conditioning (HVAC) duct directs airflow from the HVAC duct towards the heatsink. The position of the outlet on the HVAC duct may direct airflow to move parallel to the plurality of fins of the heatsink, In an example, the method may further include covering the opening of the outlet of the HVAC duct with a valve, the valve to alternatively allow or disallow airflow from the HVAC duct towards the heatsink. In this example the method may include signaling the valve to open in response to a detection by a temperature sensor of the HUD module of the temperature exceeding a first threshold temperature. Further, the method may include signaling the valve to close in response to a detection by the temperature sensor of the HUD module of the temperature of the HUD module passing below a second threshold temperature. In these examples, the first threshold temperature and the second threshold temperature are the same value. For example in which a temperature sensor is used in the method of cooling, the temperature sensor may be a thermistor located on the PGU or the heatsink. In an example, the HVAC duct is contained within an instrument panel of the vehicle. 
       FIG. 5  is a drawing of an example computer-readable medium  500  storing instructions, that when executed on a processor cools a HUD through control of an HVAC outlet valve. The tangible, non-transitory, computer-readable medium  500  includes instructions that, when executed by a processor  502  can direct the processor  502  through a bus  540  to cool a HUD. In an example, the computer-readable medium  500  may be stored on the HUD. 
     The computer-readable medium  500  includes light emitter  506  to control and signal a display or group of lights to emit light showing particular pictures, patterns, numbers, or symbols. In an example the light emitter may be controlling a PGU with an LCD screen with LED lights backlighting the LCD screen. 
     The computer-readable medium  500  may be coupled to a temperature detector  508  to detect the temperature of a PGU, HUD, or a heatsink attached to the PGU, HUD, or subcomponents of either the PGU or HUD. The computer-readable medium  500  includes a valve signaler  510  to signal a valve to open in response to the detection of the temperature by the temperature detector  508 . The valve may be attached to an HVAC duct. In an example, there may be a number of valves on a single HVAC duct responsive to the temperature detector  508 . In an example, there may be a number of valves each on a different HVAC duct that may be responsive to the temperature detector  508 .