Hybrid thermal management for silicon-based liquid crystal head-up displays

Abstract

Aspects of the present disclosure include a hybrid thermal management system configured to control an operating temperature of a liquid crystal on silicon (LCoS) based head-up display (HUD) unit. An exemplary thermal management system can include a liquid crystal on silicon layer and a phase change material on a surface of the liquid crystal on silicon layer. A thermoelectric device is positioned in direct contact with the phase change material, and a heat sink is positioned on a surface of the thermoelectric device. The thermal management system can also include a controller configured to adjust a thermoelectric device current of the thermoelectric device in response to a temperature of the liquid crystal on silicon layer.

Description

Technical Field

[0001] This invention relates to display technology, and more particularly to a hybrid thermal management solution for liquid crystal on silicon (LCoS) devices in head-up display (HUD) units. Background Technology

[0002] A head-up display (HUD) unit projects light from an image source onto a viewing surface, such as a vehicle's windshield, to display a virtual or actual image. While the image source may vary, a liquid crystal on silicon (LCoS) device, also known as a liquid crystal display, is typically chosen for this purpose. In a transmissive LCoS-based configuration, illumination light from a backlight passes through the liquid crystal display as display light, and this display light is reflected onto the viewing surface by a mirror (or concave mirror) of the HUD unit. A reflective LCoS-based configuration is also possible. By projecting reflected light onto the viewing surface (e.g., a windshield), a user (e.g., a driver) can quickly and visually recognize the virtual image projected onto it. LCoS-based HUD units can be used to provide drivers and passengers with a range of visual information without significantly shifting or obscuring their field of vision. Summary of the Invention

[0003] In one exemplary embodiment, a hybrid thermal management system for a liquid crystal on silicon (LCoS) device in a head-up display (HUD) unit includes a liquid crystal on silicon layer and a phase change material on the surface of the liquid crystal on silicon layer. A thermoelectric device is positioned in direct contact with the phase change material, and a heat sink is positioned on the surface of the thermoelectric device. The thermal management system may further include a controller configured to adjust the thermoelectric current of the thermoelectric device in response to the temperature of the liquid crystal on silicon layer.

[0004] In some embodiments, the silicon-based liquid crystal device is a liquid crystal display in a head-up display unit.

[0005] In another embodiment, the thermoelectric device is located on the top surface of the phase change material. In some embodiments, the phase change material is conformally molded onto the surface of the thermoelectric device.

[0006] In some embodiments, the hybrid thermal management system includes a thermocouple configured to measure the temperature of a silicon-based liquid crystal layer. In some embodiments, a controller is communicatively coupled to the thermocouple.

[0007] In addition to one or more features described herein, adjusting the thermoelectric current of the thermoelectric device may include determining that the temperature is above a high-temperature threshold and adjusting the thermoelectric current to achieve a normalized current within the net cooling region of the net heating and net cooling curves of the thermoelectric device. In other embodiments, adjusting the thermoelectric current of the thermoelectric device may include determining that the temperature is below a low-temperature threshold and adjusting the thermoelectric current to achieve a normalized current within the net heating region of the net heating and net cooling curves of the thermoelectric device.

[0008] In some embodiments, the phase change material includes a phase change composite material. In some embodiments, the phase change composite material includes expanded graphite embedded in paraffin wax.

[0009] In another exemplary embodiment, a method includes forming a silicon-based liquid crystal layer and forming a phase change material on the surface of the silicon-based liquid crystal layer. The method also includes forming a thermoelectric device in direct contact with the phase change material and forming a heat sink on the surface of the thermoelectric device. The method may further include providing a controller configured to adjust a thermoelectric current of the thermoelectric device in response to a temperature of the silicon-based liquid crystal layer.

[0010] In some embodiments, the silicon-based liquid crystal layer includes a liquid crystal display in a head-up display unit.

[0011] In another exemplary embodiment, the vehicle display system includes a head-up display (HUD) unit configured to project display light onto a viewing surface of the vehicle. The display system also includes a thermal management system for the HUD unit. The thermal management system may include a liquid crystal on silicon (LCD) layer and a phase change material on the surface of the LCD layer. The thermal management system may also include a thermoelectric device in direct contact with the phase change material, a heat sink on the surface of the thermoelectric device, and a controller configured to adjust the thermoelectric current of the thermoelectric device in response to the temperature of the LCD layer.

[0012] In some embodiments, the viewing surface is a glass panel of the vehicle (e.g., windshield, window, etc.).

[0013] In some embodiments, the thermoelectric device is located on the top surface of the phase change material. In some embodiments, the phase change material is conformally molded on the surface of the thermoelectric device.

[0014] In some embodiments, the thermal management system further includes thermocouples configured to measure the temperature of the silicon-based liquid crystal layer. The thermocouples may be communicatively coupled to the controller.

[0015] The above-described features and advantages, as well as other features and advantages of the present invention, will become apparent from the following detailed description taken in conjunction with the accompanying drawings. Attached Figure Description

[0016] Other features, advantages, and details appear as examples only in the following detailed description, which is illustrated in the accompanying drawings, wherein:

[0017] Figure 1A A cross-sectional view of a hybrid thermal management system for a liquid crystal on silicon (LCoS) device in a head-up display (HUD) unit formed according to one or more embodiments is depicted;

[0018] Figure 1B A cross-sectional view of a thermoelectric device according to one or more embodiments is depicted;

[0019] Figure 2 Net heating and net cooling profiles for a hybrid thermal management system configured according to one or more embodiments are depicted;

[0020] Figure 3 A cross-sectional view of a thermal management system with a conformal phase change material according to one or more embodiments is depicted;

[0021] Figure 4 A block diagram depicts the temperature control logic of a thermal management system according to one or more embodiments;

[0022] Figure 5 A series of comparative temperature response curves are depicted for an LCoS-based HUD unit having a series of thermal management systems according to one or more embodiments.

[0023] Figure 6 A computer system according to one or more embodiments; and

[0024] Figure 7 This is a flowchart according to one or more embodiments. Detailed Implementation

[0025] The following description is exemplary in nature and is not intended to limit the invention or its application or use. It should be understood that in all the drawings, corresponding reference numerals denote the same or corresponding parts and features. As used herein, the term module refers to processing circuitry, which may include application-specific integrated circuits (ASICs), electronic circuitry, processors (shared, dedicated, or grouped) and memories executing one or more software or firmware programs, combinational logic circuitry, and / or other suitable components that provide the said functionality.

[0026] The continued development of precision head-up displays (HUDs), smart glass applications, flat panel displays, and universal device displays is essential to meeting the growing needs and expectations of consumers, especially in the highly competitive automotive industry. To enhance the driver experience, improved displays are being developed that can be seamlessly integrated into any glass panel of a vehicle, such as the windshield, side mirrors, etc. For example, HUD units based on liquid crystal on silicon (LCoS) can be used to project virtual images onto a glass panel, providing drivers and passengers with a range of visual information without significantly shifting or obscuring their field of vision.

[0027] However, challenges remain in the development and manufacturing of LCoS-based head-up display (HUD) units. One such challenge is inherent in the combination of an LCoS-based display and a HUD unit; that is, since the HUD unit is located on a vehicle's glass panel (e.g., the windshield), it will be exposed to a range of hot and cold environments. Unfortunately, the performance of LCoS-based displays degrades when operating temperatures are too high or too low. The optimal temperature is approximately 70°C. Further complicating matters, active liquid cooling is impractical for HUDs due to size and energy limitations.

[0028] This invention introduces a quasi-passive method for effectively controlling the operating environment, particularly the operating temperature, of an LCoS-based head-up display (HUD) unit. Advantageously, aspects of this disclosure can maintain the target operating temperature of the LCoS display under a wide range of expected environmental conditions (e.g., a temperature range from -20°C to 60°C). Maintaining the optimal operating temperature of the LCoS display according to one or more embodiments significantly improves the operational performance and efficiency of LCoS-based HUD units.

[0029] In some embodiments, a hybrid thermal management solution combining a thermoelectric device (TED) and a phase change material (PCM) is used to control the operating environment of the LCoS display. The TED and PCM work together to maintain target operating conditions, ensuring optimal display performance. In some embodiments, the TED and PCM are stacked between the LCoS display and the heat sink to define a single hybrid thermal management device. Integrating the TED and PCM in this way advantageously allows a single hybrid device (with both TED and PCM) to function as both a heater and a cooler by adjusting the device current of the TED. In other words, net heating or cooling can be controlled by current regulation.

[0030] In some embodiments, the hybrid thermal management device utilizes the energy storage capacity of the PCM to supplement the thermoelectric cooling effect of the TED, thereby enabling thermal management requirements to be met with a TED that is less power, consumes less energy, and is smaller in size.

[0031] Although aspects of the invention have been described in the context of an LCoS display integrated within a HUD unit, it should be readily understood that the hybrid thermal management solutions described herein can be applied to any display type, such as flat panel displays (e.g., flat communication devices laminated inside or on a vehicle window for communication with users inside or outside the vehicle), smart glass applications, and displays generally based on LCoS devices.

[0032] Figure 1A A cross-sectional view of a hybrid thermal management system 100 for a liquid crystal on silicon (LCoS) device in a head-up display (HUD) unit (not shown separately) formed according to one or more embodiments is shown. Figure 1A As shown, the hybrid thermal management system 100 includes an LCoS layer 102 and a phase change material (PCM) 104 formed on the surface of the LCoS layer 102. The LCoS layer 102 is sometimes referred to as the LCoS substrate (or simply the backplate).

[0033] While not intended to be particularly limiting, the LCoS layer 102 may include any range of liquid crystal display materials known, such as semiconductor materials (e.g., silicon, gallium nitride, indium gallium nitride, etc.) in a suitable configuration (e.g., as a display backplane). For example, the LCoS layer 102 may include multiple CMOS switches and dual memory pixel arrays (not shown separately), although other LCoS backplane configurations are also contemplated within the scope of this disclosure. In some embodiments, the LCoS layer 102 includes several stacked layers, such as indium gallium nitride / gallium nitride (InGaN / Gan) stacks (not shown separately) formed on silicon or sapphire substrates. The LCoS layer 102 may include electrical connections (not shown separately) configured to individually control each of the multiple underlying pixels using electrical signals (i.e., by transmitting voltage to the respective display elements).

[0034] PCM 104 can be made from known phase change materials, such as phase change composites (PCCMs), like expanded graphite with and without paraffin embedding. The specific phase change material chosen for a given application is not intended to be particularly limited. Other phase change materials, including organic phase change materials (e.g., hydrocarbons such as paraffin, lipids, sugar alcohols, etc.), inorganic phase change materials (e.g., hydrates), and other materials that absorb or release significant latent heat during phase change, are all within the scope of this disclosure.

[0035] like Figure 1AAs shown, a thermoelectric device (TED) 106 is formed on the surface of PCM 104. The thermoelectric device responds to received current by transferring heat between the primary surface (or hot side) and the waste surface (or cold side) using the Peltier effect. In a given application, the specific configuration of TED 106 is not particularly limited and can include, for example, an alternating array of n-type and p-type semiconductors (e.g., bismuth telluride, antimony telluride, lead telluride, bismuth selenide, etc.) having complementary Peltier coefficients soldered or fixed between a pair of plates (e.g., ceramic plates, metal plates, etc.).

[0036] In some embodiments, TED 106 is configured to transfer heat between LCoS layer 102 (i.e., the hot side) and heat sink 108 (i.e., the cold side) when an electric current is applied. The operating principle of the thermoelectric device is as follows: Figure 1B As shown. Figure 1B As shown, TED 106 transfers heat "q" from the hot side 110 to the cold side 112 in response to the difference in current "i" applied across TED 106.

[0037] The heat sink 108 may be made of any suitable material, such as metals and metal alloys having high or very high thermal conductivity (e.g., aluminum, copper, and their alloys), but more specialized materials, such as thermal interface materials, are also within the scope of this invention. The heat sink 108 may include, for example, a body and one or more heat dissipation fins, although other configurations are also within the scope of this disclosure.

[0038] like Figure 1A As shown, the hybrid thermal management system 100 may include a controller 114. In some embodiments, the controller 114 is communicatively coupled to a thermocouple (not shown separately) located in, above, or near the LCoS layer 102. In some embodiments, the thermocouple measures the temperature of the LCoS layer 102 and transmits the signal ( Figure 1A The "T" in the thermocouple is sent to controller 114. A thermocouple may comprise a pair of materials (e.g., metals) joined together or coupled together for measuring heat. Thermocouples are widely used in various industries due to their accuracy and wide operating temperature range. Metals used in thermocouples include iron, nickel, copper, chromium, aluminum, platinum, rhodium, and their alloys.

[0039] In some embodiments, controller 114 is configured with temperature control logic (e.g., see...). Figure 4 In some embodiments, controller 114 is configured to initiate heating or cooling measures on LCoS layer 102 based on signal "T" and temperature control logic. (See also...) Figure 4The temperature control logic will be discussed in more detail. In some embodiments, the controller 114 is configured to send a control signal to the TED 106. In some embodiments, the control signal is a current applied to one end of the TED 106. Figure 1A The “i” in the figure is sometimes referred to as the thermoelectric current, which enables net heating or net cooling of the LCoS layer 102 due to the Peltier effect.

[0040] For ease of discussion and illustration only, the hybrid thermal management system 100 is shown with a specific arrangement (e.g., TED on top of PCM). However, it should be understood that the configuration of LCoS layer 102, PCM 104, TED 106, and heatsink 108 can vary depending on the needs of a given display application. For example, in some embodiments, the relative positions of PCM 104 and TED 106 are interchanged (also referred to as the PCM-on-TED configuration, not shown separately). In other embodiments, one or both of PCM 104 and TED 106 are wholly or partially located on opposite surfaces of LCoS layer 102 (as a single continuous structure or as two or more separate structures) (not shown separately).

[0041] Figure 2 Net heating and net cooling profiles 200 are depicted for a hybrid thermal management system 100 configured according to one or more embodiments. As previously described, the hybrid thermal management system 100 includes a PCM 104 and a TED 106, which together serve as a dual heating and cooling system for the LCoS layer 102. Thermal management profile 202 describes the heat absorption “q” (see Figure 1B ) and the thermoelectric current "I" of TED 106 (see Figure 1A The overall relationship between the two is shown. Specifically, the y-axis depicts the normalized heat absorption “q” (i.e., q / q). MAX The value is displayed between -12.0 and 12.0, where q MAX The x-axis represents the maximum heat absorption for the corresponding application, while the x-axis depicts the normalized current (i.e., I / I0). MAX The value is displayed between -1.5 and 3.0, where I MAX (This is the maximum thermoelectric current for the corresponding application). Negative "q" values ​​indicate net heating zones 204 and 206, while positive "q" values ​​indicate net cooling zone 208.

[0042] Thermal management curve 202 represents the net effect of three main potential mechanisms: Peltier heat absorption, Joule heating, and conduction. Specifically, the overall relationship between heat absorption and current is described by equation (1):

[0043]

[0044] Q cIt is the total heat absorption (or dissipation), αITc describes the cooling (heat absorption) due to the Peltier effect, (1 / 2)I 2 R describes KΔT due to Joule heating that overcomes the resistance in TED 106. p It is the heat flow through conduction.

[0045] Peltier cooling curve 210 shows the total heat transfer contribution of Peltier heat absorption as a function of the thermoelectric device current "I". Joule heating curve 212 shows the total heat transfer contribution of Joule heating as a function of the thermoelectric device current "I". Conduction curve 214 shows the total heat transfer contribution of conduction as a function of the thermoelectric device current "I".

[0046] like Figure 2 As shown, net heating and net cooling of the LCoS layer 102 can be achieved by changing the thermoelectric device current I. It was observed that in some embodiments, net heating is achieved at normalized thermoelectric device currents of -1.5 to 0.25 and 1.75 to 3.0, while net cooling is achieved at normalized thermoelectric device currents between 0.25 and 1.75.

[0047] Figure 3 A cross-sectional view of an embodiment of a thermal management system 100 having a conformal PCM 104 is depicted. Figure 3 The thermal management system 100 shown can be used with Figure 1A The thermal management system 100 shown is configured in a similar manner and with similar materials. For clarity, the LCoS layer 102 has been omitted. Figure 1A However, it will exist in the final device.

[0048] In some embodiments, the conformal PCM 104 comprises a PCCM conformally molded onto the surface of one or both of the TED 106 and the heatsink 108. Depending on the size and configuration of the TED 106 and the heatsink 108, the conformal PCM 104 can be formed to any desired nominal (average) thickness, such as from 0.5 mm to several inches. Advantageously, conformally molding the PCM 104 to the TED 106 and / or the heatsink 108 in this manner allows for an increase in the volume of the phase change material without increasing the overall size of the thermal management system 100.

[0049] In some embodiments, the latent heat of fusion of PCM 104 is utilized to maintain the desired temperature range of LCoS layer 102 without requiring current at TED 106 (or requiring relatively low current compared to when no phase change material is used). In particular, the heat of fusion of the phase change material can be used to suppress heat load spikes (e.g., rapid increases in ambient temperature, such as when a vehicle is moved from a garage into sunlight). In other words, PCM 104 is used to level off the heat load because PCM 104 can absorb a significant amount of heat before undergoing a phase change. Although discussed in the context of latent heat of fusion, other phase change materials and structures that utilize latent heat of vaporization as much as possible are also within the scope of this disclosure.

[0050] Figure 4 A block diagram depicts temperature control logic 400 of a thermal management system configured according to one or more embodiments. In some embodiments, the controller (e.g., Figure 1A The controller 114 is configured to evaluate temperature control logic 400 to maintain the liquid crystal display (e.g., Figure 1A The target temperature of the LCoS layer 102.

[0051] In box 402, the current temperature of the liquid crystal display (“T”) is displayed. LCOS ") and target temperature ("T) SET The current temperature can be measured using any suitable equipment or technology, for example, by a thermocouple (not shown separately) located in, above, or near LCoS layer 102.

[0052] In box 404, a high-temperature inspection is evaluated. In some embodiments, this is achieved by determining T... LCOS Is it higher than T? SET (that is, if T) LCOS -T SET The temperature check is evaluated to be >0). If the high-temperature check is evaluated as true, the temperature control logic 400 proceeds to block 406 and initiates cooling measures. In some embodiments, the cooling measures may include changing the thermoelectric current of TED 106 according to the net heating and net cooling curve 200 to achieve a net cooling zone 208 (i.e., "Δi→208"). For example, if the normalized current is -1.0, the current may be increased to 1.0 (or equal to 0). Figure 2 The net cooling area 208 shown is associated with any number between approximately 0.25 and 1.75. In another example, if the normalized current is 2.5, the current can be reduced to 1.0 (or...). Figure 2 The net cooling area 208 shown is associated with any number between approximately 0.25 and 1.75.

[0053] Observing T LCOS With T SETThe comparison requires strict adherence to the target temperature (i.e., any temperature above T). SET Deviations will lead to cooling measures. To provide some thermal flexibility, in some embodiments, relative to the high temperature threshold ("T"), HIGH (That is, if T) LCOS -T HIGH >0), alternatively evaluate high-temperature inspection. T HIGH It can be set to be higher than T. SET Any temperature. For example, if T SET It's 70 degrees Celsius, T HIGH It can be 72 degrees Celsius. In this way, the intensity of the cooling measures can be fine-tuned according to the needs of a specific application.

[0054] If the high-temperature check at box 404 is evaluated as false, the temperature control logic 400 proceeds to box 408 and evaluates the low-temperature check.

[0055] In some embodiments, by determining T LCOS Is it lower than T? SET (i.e., whether T) LCOS -T SET <0) to evaluate the low-temperature check. If the low-temperature check is evaluated as true, temperature control logic 400 proceeds to block 410 and heating measures are initiated. In some embodiments, the heating measures may include varying the thermoelectric current of TED 106 according to the net heating and net cooling curves 200 to achieve one of the net heating regions 204, 206 (i.e., "Δi→204,206"). For example, if the normalized current is 0.5, the current may be reduced to -0.5 (or reduced to a value similar to...). Figure 2 The net heating area 204 shown is associated with any number between approximately -1.5 and 0.25. Optionally, the current can be increased to 2.5 (or increased to a value similar to...). Figure 2 (Any number between approximately 1.75 and 3.0 associated with the net heating region 206 shown). In some embodiments, increasing or decreasing the current is preferably done in the direction closest to the net heating regions 204, 206. In some embodiments, increasing or decreasing the current is preferably done in the direction of the region of the net heating regions 204, 206, which minimizes energy usage.

[0056] Note again that T LCOS With T SET The comparison requires strict adherence to the target temperature (i.e., below T). SET Any deviation will affect the heating measures. To provide some thermal flexibility, in some embodiments, a low-temperature threshold (“T”) is used as a reference. LOW (That is, if T) LCOS -T LOW<0), alternatively evaluate cryotherapy. T LOW It can be set to be lower than T SET Any temperature. For example, if T SET It's 70 degrees Celsius, T LOW It can be 68 degrees Celsius. In this way, the intensity of the heating measures can be fine-tuned according to the needs of a specific application.

[0057] If T LCOS In T HIGH and T LOW Between (or strictly speaking in T) SET If the temperature is not high enough, no heating or cooling is required. Temperature control logic 400 returns to block 402 and evaluates the new current temperature. Similarly, after the heating measures at block 406 and the cooling measures at block 410 are completed, temperature control logic 400 returns to block 402 and evaluates the new current temperature. In some embodiments, a predetermined delay must occur before the new current temperature is evaluated.

[0058] Figure 5 A series of contrast temperature response curves 500 are depicted for a LCoS-based head-up display unit having a series of thermal management systems according to one or more embodiments. Each contrast temperature response curve 500 describes the temperature "T" of the liquid crystal display exposed to a heat load (e.g., temperature). Figure 4 T in LCOS The relationship between the temperature response curve 502 and the elapsed time “t” is shown. The temperature response curve 502 shows the baseline temperature response of the liquid crystal display in the HUD unit without the use of phase change materials or thermoelectric devices.

[0059] Temperature response curve 504 illustrates the temperature response of the liquid crystal display in the head-up display unit with a thermoelectric device, but without the use of a phase change material. The overall temperature response is observed to be relatively faster than the baseline temperature response of temperature response curve 502. Further observation shows that after approximately 200 seconds, the temperature response drifts above the target temperature range of 550°C (i.e., T...). SET Or as mentioned before, in T HIGH and T LOW between).

[0060] Temperature response curve 506 shows the temperature response of a liquid crystal display in a head-up display unit with a phase change material but without thermoelectric devices. The overall temperature response was observed to be relatively faster than the baseline temperature response of temperature response curve 502, but relatively slower than the measurements of temperature response curve 504 (TED only). Further observation revealed that the temperature response ultimately failed to maintain the temperature within the target temperature range of 550°C. For example, the temperature rapidly increased after approximately 500 seconds. This period corresponds to the thermal saturation of the phase change material and the transition from the latent heat of the molten state to the sensible heat of the phase change material (now a liquid).

[0061] Temperature response curve 508 illustrates the temperature response of the liquid crystal display in the head-up display unit with thermoelectric devices and phase change materials. The overall temperature response is observed to be relatively faster than the baseline temperature response of temperature response curve 502. Furthermore, the temperature response is observed to remain within the target temperature range of 550°C throughout the entire thermal load test (e.g., over 600 seconds).

[0062] Figure 6 Various aspects of an embodiment of a computer system 600 capable of performing the aspects of the embodiments described herein are illustrated. In some embodiments, the computer system 600 may be incorporated within or combined with an LCoS-based HUD unit (e.g., a hybrid thermal management system 100). The computer system 600 includes at least one processing device 602, which typically includes one or more processors (e.g., Figure 1A The controller 114 is used to perform various functions, such as controlling the thermoelectric current at TED 106. More specifically, the computer system 600 may include temperature control logic 400 (e.g., as...). Figure 4 As shown), the temperature control logic 400 is necessary to initiate heating or cooling measures by adjusting the current of the thermoelectric device.

[0063] The computer system 600 includes a processing device 602 (such as one or more processors or processing units), a system memory 604, and a bus 606 connecting various system components, including the system memory 604, to the processing device 602. The system memory 604 may include various computer system readable media. Such media may be any available media accessible by the processing device 602, and includes volatile and non-volatile media, as well as removable and non-removable media.

[0064] For example, system memory 604 may include non-volatile memory 608, such as a hard disk, and may also include volatile memory 610, such as random access memory (RAM) and / or cache memory. Computer system 600 may also include other removable / non-removable, volatile / non-volatile computer system storage media.

[0065] System memory 604 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the embodiments described herein. For example, system memory 604 stores various program modules that generally perform the functions and / or methods of the embodiments described herein. One or more modules 612, 614 may be included to perform functions related to the control of the hybrid thermal management system 100, such as comparing the current LCoS display temperature (measured using, for example, a thermocouple) with a target temperature (i.e., a setpoint such as 70 degrees Celsius) or a threshold (i.e., a high / low threshold associated with the target temperature) and regulating the current sent to TED (e.g., TED 106). Computer system 600 is not limited thereto, as other modules may be included depending on the desired functions of the individual displays. As used herein, the term "module" refers to processing circuitry, which may include application-specific integrated circuits (ASICs), electronic circuitry, processors (shared, dedicated, or grouped) and memory executing one or more software or firmware programs, combinational logic circuitry, and / or other suitable components that provide the functions described herein. For example, according to one or more embodiments, the module can be configured via software, hardware, and / or firmware to maintain the liquid crystal display (e.g., Figure 1A The target temperature of the LCoS layer 102.

[0066] The processing device 602 may also be configured to communicate with one or more external devices 616, such as a keyboard, a pointing device, and / or any device (e.g., a network card, a modem, a vehicle ECU, etc.), enabling the processing device 602 to communicate with one or more other computing devices. Communication with various devices can be made through input / output (I / O) interfaces 618 and 620.

[0067] The processing device 602 can also communicate with one or more networks 622 via network adapter 624, such as a local area network (LAN), a general wide area network (WAN), a bus network, and / or a public network (e.g., the Internet). In some embodiments, network adapter 624 is or includes an optical network adapter for communication via an optical network. It should be understood that, although not shown, other hardware and / or software components may be used in conjunction with computer system 600. Examples include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, and data archiving storage systems.

[0068] Now for reference Figure 7 According to one embodiment, a flowchart 700 is generally shown to control the operating temperature of an LCoS-based HUD unit using a hybrid thermal management system. (Reference) Figures 1A to 6 Flowchart 700 is described, and flowchart 700 may include Figure 7additional steps not shown in. Although depicted in a specific order, Figure 7 the blocks depicted in may be rearranged, subdivided, and / or combined.

[0069] In block 702, a liquid crystal on silicon layer is formed. In some embodiments, the liquid crystal on silicon layer comprises a liquid crystal display in a head-up display unit.

[0070] In block 704, a phase change material is formed on the surface of the liquid crystal on silicon layer. In some embodiments, the phase change material comprises a phase change composite material (PCCM). In some embodiments, the PCCM comprises expanded graphite embedded with paraffin.

[0071] In block 706, a thermoelectric device in direct contact with the phase change material is formed. In some embodiments, the thermoelectric device is formed or otherwise positioned on the top surface of the phase change material. In some embodiments, the phase change material is conformally molded onto the surface of the thermoelectric device.

[0072] In block 708, a heat sink is formed on the surface of the thermoelectric device. In some embodiments, the heat sink is an aluminum heat sink with one or more fins.

[0073] In block 710, a controller is provided that is configured to adjust the thermoelectric device current of the thermoelectric device in response to the temperature of the liquid crystal on silicon layer. In some embodiments, a thermocouple is configured to measure the temperature of the liquid crystal on silicon layer. In some embodiments, the controller is communicatively coupled to the thermocouple.

[0074] In some embodiments, adjusting the thermoelectric device current of the thermoelectric device comprises determining that the temperature is greater than a high temperature threshold, and adjusting the thermoelectric device current to achieve a normalized current within the net cooling region of the net heating and net cooling curve of the thermoelectric device.

[0075] In some embodiments, adjusting the thermoelectric device current of the thermoelectric device comprises determining that the temperature is lower than a low temperature threshold, and adjusting the thermoelectric device current to achieve a normalized current within the net heating region of the net heating and net cooling curve of the thermoelectric device.

[0076] Although the above disclosure has been described with reference to exemplary embodiments, those skilled in the art shall understand that various changes may be made thereto and equivalent substitutions may be made to its elements without departing from its scope. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within the scope thereof.

Claims

1. A thermal management system for a silicon-based liquid crystal device, the thermal management system comprising: Silicon-based liquid crystal layer; Phase change material on the surface of a silicon-based liquid crystal layer; Thermoelectric devices that come into direct contact with phase change materials; Radiators on the surface of thermoelectric devices; and The controller is configured to adjust the thermoelectric current of the thermoelectric device in response to the temperature of the silicon-based liquid crystal layer. The phase change material is conformally molded onto the surface of the thermoelectric device.

2. The system according to claim 1, wherein the silicon-based liquid crystal device includes a liquid crystal display in a head-up display unit.

3. The system of claim 1, wherein the thermoelectric device is located on the top surface of the phase change material.

4. The system of claim 1 further includes a thermocouple configured to measure the temperature of the silicon-based liquid crystal layer.

5. The system of claim 4, wherein the controller is communicatively coupled to the thermocouple.

6. The system according to claim 1, wherein adjusting the thermoelectric current of the thermoelectric device comprises: Determine that the temperature is greater than the high temperature threshold; and The current of the thermoelectric device is adjusted to achieve a normalized current within the net cooling region of the net heating and net cooling curves of the thermoelectric device.

7. The system according to claim 1, wherein adjusting the thermoelectric current of the thermoelectric device comprises: Determine that the temperature is below the low-temperature threshold; and The current of the thermoelectric device is adjusted to achieve a normalized current within the net heating region of the net heating and net cooling curves of the thermoelectric device.

8. The system according to claim 1, wherein the phase change material comprises a phase change composite material.

9. The system of claim 8, wherein the phase change composite material comprises expanded graphite embedded in paraffin.

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