ELECTRONIC DISPLAY ASSEMBLY WITH THERMAL MANAGEMENT

Abstract

Systems and methods for reducing solar loading of an electronic image assembly are provided. A cover panel forms a portion of a housing, is spaced apart from an electronic display, and permits viewing of images displayed at the electronic display. An airflow pathway extends between the electronic display and the cover panel and behind the electronic display. An air circulation device moves air through the airflow pathway. A second air circulation device moves airflow through a second airflow pathway within the housing which forms a closed loop around the electronic display. At least one solar energy reduction layer is located at an interior of the cover panel.

Claims

1. An electronic image assembly with thermal management features, said electronic image assembly comprising: an electronic display; a housing for the electronic display; a cover panel forming a portion of the housing, wherein the cover panel is located at least some distance from the electronic display and enables viewing of images displayed at the electronic display; a first airflow pathway extending within said housing rearward of the electronic display; a second airflow pathway extending within said housing, forming a closed loop; a first air circulation device configured to assist ambient air through the first airflow pathway; a second air circulation device configured to move circulating gas through said second airflow pathway; and at least one polarizer located at an inward facing surface of said cover panel, wherein said second airflow pathway extends between a forward surface of said electronic display and a rear surface of said at least one polarizer, and further extends behind said electronic display.

2. The electronic image assembly of claim 1 further comprising: an inlet located at a first portion of said housing for ingesting said ambient air into said first airflow pathway; and an exhaust located at a second portion of said housing for exhausting said ambient air from said first airflow pathway, wherein the first air circulation device comprises a first fan located rearward of the electronic display, and the second air circulation device comprises a second fan located rearward of the electronic display.

3. The electronic image assembly of claim 1 wherein: the electronic display comprises a layer of liquid crystals and a backlight; and the first airflow pathway extends along the backlight.

4. The electronic image assembly of claim 3 wherein: the first airflow pathway extends interior to said closed loop.

5. The electronic image assembly of claim 1 further comprising: at least one film having anti-reflection properties located at said cover panel.

6. The electronic image assembly of claim 1 further comprising: at least one additional polarizer located at a forward surface of the electronic display.

7. The electronic image assembly of claim 1 further comprising: a filter provided within the second airflow pathway.

8. The electronic image assembly of claim 1 wherein: the second airflow pathway is sealed from the first airflow pathway sufficient to prevent contaminates above a specific size from entering the second airflow pathway.

9. The electronic image assembly of claim 1 further comprising: fins extending from a wall of the second airflow pathway into the first airflow pathway.

10. The electronic image assembly of claim 9 wherein: the surface features comprise fins; and the first airflow pathway extends interior to said second airflow pathway.

11. The electronic image assembly of claim 1 wherein: at least a majority of the first airflow pathway extends adjacent to at least a majority of a portion of the second airflow pathway which extends behind said electronic display.

12. An electronic image assembly with thermal management features, said electronic image assembly comprising: an electronic display; a housing for the electronic display, wherein said electronic display comprises an electronic display layer comprising liquid crystals and a backlight; a cover panel forming a forward portion of the housing, the cover panel located forward of, and at least some distance from, the electronic display and configured to permit viewing of images displayed at said electronic display through said cover panel; a first airflow pathway extending within said housing behind and along at least a portion of a rear surface of the backlight, wherein said first airflow pathway is configured to accommodate ambient air; a second airflow pathway extending within said housing and around said electronic display, wherein at least a first portion of said second airflow pathway extends adjacent at least a portion of the first airflow pathway to facilitate thermal interaction between circulating gas in the first portion of said second airflow pathway and said ambient air in said first airflow pathway; and at least one solar energy reduction layer provided at an interior facing surface of said cover panel, wherein a second portion of said second airflow pathway extends between a rear surface of said at least one solar energy reduction layer and a front surface of said electronic display layer; wherein said first portion of said second airflow pathway is in fluid communication with said second portion of said second airflow pathway and forms a closed loop; wherein said first portion of said second airflow pathway is spaced apart from the rear surface of said backlight.

13. The electronic image assembly of claim 12 further comprising: an inlet located at a first portion of said housing for ingesting said ambient air into said first airflow pathway; an exhaust located at a second portion of said housing for exhausting said ambient air from said first airflow pathway; a first fan assembly positioned along said first airflow pathway between said inlet and said exhaust and configured to force said ambient air through the first airflow pathway when said first fan assembly is activated; and a second fan assembly positioned along said second airflow pathway to force said circulating gas around the second airflow pathway when said second fan assembly is activated.

14. The electronic image assembly of claim 12 wherein: said at least one solar energy reduction layer comprises a polarizer.

15. The electronic image assembly of claim 14 wherein: said electronic display comprises at least one polarizer located forward of the electronic display layer; and said cover panel comprises at least two glass panels.

16. The electronic image assembly of claim 12 further comprising: electronic components for the electronic display located within the second airflow pathway.

17. The electronic image assembly of claim 16 further comprising: fins extending from a wall of the first portion of the second airflow pathway into the first airflow pathway, wherein the first airflow pathway extends interior to the second airflow pathway.

18. The electronic image assembly of claim 12 further comprising: a filter located within the second airflow pathway.

19. The electronic image assembly of claim 12 wherein: the second airflow pathway is sealed from the first airflow pathway sufficient to prevent contaminates above a specific size from entering the second airflow pathway.

20. An electronic image assembly with thermal management features, said electronic image assembly comprising: an electronic display comprising at least one polarizer, liquid crystals, and a backlight; a housing for the electronic display; a cover panel forming a forward portion of the housing, wherein the cover panel is spaced apart from the electronic display and enables viewing of images displayed at the electronic display; a first airflow pathway extending interior to said housing and rearward of the electronic display; a second airflow pathway forming a closed loop; a first fan located within the first airflow pathway for moving ambient air through the first airflow pathway when activated; a second fan located within the second airflow pathway for moving circulating gas through said second airflow pathway when activated; at least one polarizer located at an inward facing surface of said cover panel, wherein a first portion of said second airflow pathway is located between a forward surface of said electronic display and a rearward surface of said at least one polarizer and a second portion of the second airflow pathway is located rearward of the electronic display; and electronic components for operating the electronic display located within the second portion of the second airflow pathway; wherein the second airflow pathway is sealed from the first airflow pathway and an ambient environment in a manner which prevents contaminates above a specific size from the first airflow pathway and the ambient environment from entering the second airflow pathway; wherein at least a majority of the first airflow pathway extends adjacent to at least a majority of the second portion of the second airflow pathway.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A better understanding of an exemplary embodiment will be obtained from a reading of the following detailed description and the accompanying drawings wherein identical reference characters refer to identical parts and in which:

[0012] FIG. 1 is a perspective view of an exemplary embodiment in conjunction with an exemplary electronic display.

[0013] FIG. 2 is an exploded perspective view of an exemplary embodiment showing components of the isolated gas cooling system.

[0014] FIG. 3 is top plan view of an exemplary embodiment of the cooling chamber.

[0015] FIG. 4 is a front perspective view of an embodiment of the isolated cooling chamber, particularly the transparent anterior surface of first gas chamber.

[0016] FIG. 5 is a rear perspective view of an embodiment of the isolated cooling chamber, particularly the cooling plenum.

[0017] FIG. 6 is a rear perspective view of an embodiment of the isolated cooling chamber showing surface features that may be included on the plenum

[0018] FIG. 7 is a top plan view of an exemplary embodiment of the cooling chamber showing surface features that may be included on the plenum.

[0019] FIG. 8 is a front perspective view of an embodiment of the isolated cooling chamber with included thermoelectric modules.

[0020] FIG. 9 is a top plan view of an exemplary embodiment of the cooling chamber with included thermoelectric modules.

[0021] FIG. 10 is an exploded perspective view of an exemplary embodiment showing components of the isolated gas cooling system.

[0022] FIG. 11 is a cross-sectional view through one exemplary embodiment.

[0023] FIG. 12 is a cross-sectional view through one exemplary embodiment.

DETAILED DESCRIPTION

[0024] Embodiments relate to a cooling system for the electronic components of an electronic display and to combinations of the cooling system and the electronic display. Exemplary embodiments provide an isolated gas cooling system for an electronic display. Such an isolated gas cooling system is the subject matter of U.S. Application No. 61/033,064, incorporated by reference herein.

[0025] As shown in FIG. 1, when the display 10 is exposed to outdoor elements, the temperatures inside the display 10 will vary greatly without some kind of cooling device. As such, the electronics including the display screen (e.g., LCD screen) will have a greatly reduced life span. By implementing certain embodiments of the cooling system disclosed herein, temperature fluctuation is greatly reduced. This cooling capability has been achieved in spite of the fact that larger screens generate more heat than smaller screens.

[0026] The display shown is equipped with an innovative gas cooling system. Accordingly, it may be placed in direct sunlight. Although the cooling system may be used on smaller displays, it is especially useful for larger LCD, LED, or organic light emitting diodes (OLED) displays. These screens, especially with displays over 24 inches, face significant thermoregulatory issues in outdoor environments.

[0027] In FIG. 1, the display area of the electronic display shown includes a narrow gas chamber that is anterior to and coextensive with the electronic display surface. The display shown also is equipped with an optional air curtain device 114 which is the subject matter of co-pending U.S. application Ser. No. 11/941,728, incorporated by reference herein. Optionally, the display also has a reflection shield 119, to mitigate reflection of the sunlight on the display surface. Additionally, in outdoor environments, housing 70 is preferably a color which reflects sunlight.

[0028] It is to be understood that the spirit and scope of the disclosed embodiments includes cooling of displays including, but not limited to LCDs. By way of example and not by way of limitation, exemplary embodiments may be used in conjunction with displays selected from among LCD (including TFT or STN type), light emitting diode (LED), organic light emitting diode (OLED), field emitting display (FED), cathode ray tube (CRT), and plasma displays. Furthermore, embodiments may be used with displays of other types including those not yet discovered. In particular, it is contemplated that the system may be well suited for use with full color, flat panel OLED displays. While the embodiments described herein are well suited for outdoor environments, they may also be appropriate for indoor applications (e.g., factory environments) where thermal stability of the display may be at risk.

[0029] As shown in FIG. 2 an exemplary embodiment 10 of the electronic display and gas cooling system includes an isolated gas cooling chamber 20 contained within an electronic display housing 70. A narrow transparent first gas chamber is defined by spacers 100 and transparent front plate 90. A second transparent front plate 130 may be laminated to front plate 90 to help prevent breakage of front glass 90. As shown in FIG. 2, cooling chamber 20 may surround LCD stack 80 and associated backlight panel 140.

[0030] The gas cooling system 10 shown in FIG. 2 may include means for cooling gas contained within the second gas chamber. These means may include a fan 60 which may be positioned at the base of the display housing 70. The fan will force the cooler ingested air over the exterior surfaces of a posterior cooling plenum 45. If desired, an air conditioner (not shown) may also be utilized to cool the air which contacts the external surfaces of plenum 45.

[0031] Referring to FIG. 3, in at least one embodiment the isolated gas cooling chamber 20 comprises a closed loop which includes a first gas chamber 30 (see FIG. 3) and a second gas chamber 40. The first gas chamber includes a transparent plate 90. The second gas chamber comprises a cooling plenum 45. The term “isolated gas” refers to the fact that the gas within the isolated gas cooling chamber 20 is essentially isolated from external air in the housing of the display. Because the first gas chamber 30 is positioned in front of the display image, the gas should be substantially free of dust or other contaminates that might negatively affect the display image.

[0032] Various electronic components 200 are shown in various positions throughout the plenum 45. Placing these components 200 within the plenum allows for increased air flow around the components 200 and increased cooling. Further, location of the components 200 within the plenum 45 can help satisfy space considerations, as well as manufacturing and repair considerations. These components 200 may be mounted directly on the walls or surfaces of the plenum 45, or may be suspended by rods or posts 210. The precise mounting of the components 200 can vary depending on the amount of cooling that is required for the component, manufacturing limitations, wire routing benefits, or ease of repair or replacement of the specific component. Further, the precise wiring of the components 200 can vary depending on similar factors. The wiring may pass through a single hole in the plenum 45 and then spread to each component or there may be various holes in the plenum 45 to accommodate the wiring for each component individually. In a further embodiment, PCB boards and other typical electronic mounting surfaces may be integrated into the plenum 45 such that the mounting board itself substitutes as a portion of the plenum wall.

[0033] The isolated gas may be almost any transparent gas, for example, normal air, nitrogen, helium, or any other transparent gas. The gas is preferably colorless so as not to affect the image quality. Furthermore, the isolated gas cooling chamber need not necessarily be hermetically sealed from the external air. It is sufficient that the gas in the chamber is isolated to the extent that dust and contaminates may not substantially enter the first gas chamber.

[0034] In the closed loop configuration shown in FIG. 3, the first gas chamber 30 is in gaseous communication with the second gas chamber 40. A cooling chamber fan 50 may be provided within the posterior plenum 45. The cooling fan 50 may be utilized to propel gas around the isolated gas cooling chamber 20. The first gas chamber 30 includes at least one front glass 90 mounted in front of an electronic display surface 85. The front glass 90 may be set forward from the electronic display surface 85 by spacers 100 (see FIG. 4). The spacing members 100 define the depth of the narrow channel passing in front of the electronic display surface 85. The spacing members 100 may be independent or alternatively may be integral with some other component of the device (e.g., integral with the front plate). The electronic display surface 85, the spacing members, and the transparent front plate 90 define a narrow first gas chamber 30. The chamber 30 is in gaseous communication with plenum 45 through entrance opening 110 and exit opening 120.

[0035] As shown in FIG. 3, a posterior surface of the first gas chamber 30 preferably comprises the electronic display surface 85 of the display stack 80. As the isolated gas in the first gas chamber 30 traverses the display it contacts the electronic display surface 85. Contacting the cooling gas directly to the electronic display surface 85 enhances the convective heat transfer away from the electronic display surface 85.

[0036] Advantageously, in exemplary embodiments the electronic display surface 85 comprises the posterior surface of the first gas chamber 30. Accordingly, the term “electronic display surface” refers to the front surface of a typical electronic display (in the absence of the embodiments disclosed herein). The term “viewable surface” or “viewing surface” refers to that portion of the electronic display surface from which the electronic display images may be viewed by the user.

[0037] The electronic display surface 85 of typical displays is glass. However, neither display surface 85, nor transparent front plate 90, nor optional second transparent front plate 130 need necessarily be glass. Therefore, the term “glass” will be used herein interchangeably with the term plate. By utilizing the electronic display surface 85 as the posterior surface wall of the gas compartment 30, there may be fewer surfaces to impact the visible light traveling through the display. Furthermore, the device will be lighter and cheaper to manufacturer.

[0038] Although the embodiment shown utilizes the electronic display surface 85, certain modifications and/or coatings (e.g., anti-reflective coatings) may be added to the electronic display surface 85, or to other components of the system in order to accommodate the coolant gas or to improve the optical performance of the device. In the embodiment shown, the electronic display surface 85 may be the front glass plate of a liquid crystal display (LCD) stack. However, almost any display surface may be suitable for embodiments of the present cooling system. Although not required, it is preferable to allow the cooling gas in the first gas chamber 30 to contact the electronic display surface 85 directly. In this way, the convective effect of the circulating gas will be maximized. Preferably the gas, which has absorbed heat from the electronic display surface 85 may then be diverted to the cooling plenum 45 where the collected heat energy in the gas may be dissipated into the air within the display housing 70 by conductive and or convective means.

[0039] To prevent breakage, the optional second surface glass 130 may be adhered to the front surface of glass 90. Alternatively, surface glass 90 may be heat tempered to improve its strength. As shown in FIG. 3, fan 50 propels a current of air around the loop (see arrows) of the isolated gas cooling chamber 20. The plenum 45 defining the second gas chamber 40 is adapted to circulate the gas behind the electronic display surface 85. The plenum 45 preferably surrounds most of the heat generating components of the electronic display, for example, backlight panel 140 (e.g., an LED backlight).

[0040] FIG. 4 shows that the anterior surface 90 of the first gas chamber 30 is transparent and is positioned anterior to and at least coextensive with a viewable area of an electronic display surface 85. The arrows shown represent the movement of the isolated gas through the first gas chamber 30. As shown, the isolated gas traverses the first gas chamber 30 in a horizontal direction. Although cooling system 20 may be designed to move the gas in either a horizontal or a vertical direction, it is preferable to propel the gas in a horizontal direction. In this way, if dust or contaminates do enter the first gas chamber 30, they will tend to fall to the bottom of chamber 30 outside of the viewable area of the display. The system may move air left to right, or alternatively, right to left.

[0041] As is clear from FIG. 4, to maximize the cooling capability of the system, the first gas chamber 30 preferably covers the entire viewable surface of the electronic display surface 85. Because the relevant surfaces of the first gas chamber 30 as well as the gas contained therein are transparent, the image quality of the display remains excellent. Anti-reflective coatings may be utilized to minimize specular and diffuse reflectance. After the gas traverses the first gas chamber 30 it exits through exit opening 120. Exit opening 120 defines the entrance junction into the rear cooling plenum 45.

[0042] FIG. 5 shows a schematic of the rear cooling plenum 45 (illustrated as transparent for explanation). One or more fans 50 within the plenum may provide the force necessary to move the isolated gas through the isolated gas cooling chamber. Various electronic components 200 can be located anywhere throughout the second gas chamber 40. Again, these components can be mounted directly on the walls of the chamber or supported on rods or posts 210. Thus, the cooling plenum 45 can be designed to not only take heat from the first gas chamber 30 but also to take heat from these various electronic components 200. Plenum 45 may have various contours and features to accommodate the internal structures within a given electronic display application.

[0043] As can be discerned in FIGS. 6 and 7, various surface features 150 may be added to improve heat dissipation from the plenum 45. These surface features 150 provide more surface area to radiate heat away from the gas within the second gas chamber 40. These features 150 may be positioned at numerous locations on the surfaces of the plenum 45. These features may be used to further facilitate the cooling of various electronic components 200 which may also be located within the plenum 45.

[0044] Referring to FIGS. 8 and 9, one or more thermoelectric modules 160 may be positioned on at least one surface of the plenum 45 to further cool the gas contained in the second gas chamber 40. The thermoelectric modules 160 may be used independently or in conjunction with surface features 150. Alternatively, thermoelectric modules 160 may be useful to heat the gas in the rear plenum if the unit is operated in extreme cold conditions. Thermoelectric modules 160 may also be used to further facilitate the cooling or heating of various electronic components 200 which may also be located within the plenum 45.

[0045] FIG. 10 shows an exemplary method for removing heat in the gas contained in the rear plenum 45. Fan 60 may be positioned to ingest external air and blow that air into the display housing 70. Preferably, the air will contact the anterior and posterior surfaces of the plenum 45. Furthermore, in this configuration, fan 60 will also force fresh air past the heat generating components of the electronic display (e.g., the TFT layer, backlight, transformers, circuit boards, resistors, capacitors, batteries, power transformers, motors, illumination devices, wiring and wiring harnesses, and switches) to further improve the cooling capability of the cooling system. The heated exhaust air may exit through one or more apertures 179 located on the display housing 70. In a preferred embodiment, the air from this external fan 60 should not enter the isolated cooling system as this would introduce dust and contaminates into the otherwise clean gas.

[0046] Besides thermoelectric modules 160, there are a number of ways to cool the gas in the second gas chamber. For example, air conditioners or other cooling means known by those skilled in the art may be useful for cooling the gas contained in plenum 45.

[0047] While the display is operational, the isolated gas cooling system may run continuously. However, if desired, a temperature sensor (not shown) and a switch (not shown) may be incorporated within the electronic display 10. The thermostat may be used to detect when temperatures have reached a predetermined threshold value. In such a case, the isolated gas cooling system may be selectively engaged when the temperature in the display reaches a predetermined value. Predetermined thresholds may be selected and the system may be configured with a thermostat (not shown) to advantageously keep the display within an acceptable temperature range.

[0048] An optional air filter (not shown) may be employed within the plenum to assist in preventing contaminates and dust from entering the first gas chamber 30.

[0049] FIG. 11 is a cross-sectional view of an exemplary embodiment. In the arrangement shown, a first front glass 90 and a second front glass 130 may be laminated together. The first and second front glass 130 and 90 may be fixed to one another with a layer of index matched optical adhesive 200 to form a front glass unit 206. The first and second front glasses 130 and 90 may be laminated to one another through the process described in U.S. application Ser. No. 12/125,046, which is incorporated herein as if fully rewritten. The LCD stack 80 may comprise an electronic display 212 interposed between a front polarizer 216 and a rear polarizer 214. In other embodiments, the LCD may be any layer or surface used to construct an electronic display. The LCD stack 80 and the front glass unit 206 define an insulator gap 300. The depth of the insulator gap 300 may be controlled by spacers 100 (shown in FIG. 2). The insulator gap 300 serves to thermally separate the front glass unit 206 from the LCD stack 80. This thermal separation localizes the heat on the front glass unit rather than allowing solar loading of the LCD stack 80. In some embodiments, the insulator gap 300 may be devoid of any gaseous material. In other embodiments, the insulator gap 300 may be the first gas chamber 30. In other embodiments, the insulator gap 300 may be filled with any substantially transparent gas.

[0050] The second front glass may have a first surface 202 and a second surface 208. The first surface 202 may be exposed to the elements; while the second surface 208 may be fixed to the first front glass 90 by the index matched optical adhesive 200. The first front glass may have a third surface 210 and a fourth surface 204. The third surface 210 may be fixed to the second front glass 130 by the index matched optical adhesive 200; while the fourth surface may be directly adjacent to the insulator gap 300. In some embodiments, to decrease the solar loading of the LCD stack 80 and improve the viewable image quality, an anti-reflective coating may be applied to the first surface 202 and the fourth surface 204. In other embodiments, the anti-reflective coating may only be applied to at least one of the first, second, third, or fourth surface 202, 208, 210, and 204.

[0051] FIG. 12 is a cross-sectional view of another exemplary embodiment of the front glass unit 206. In the arrangement shown, the front glass unit 206 comprises a second front glass 130, a layer of index matched optical adhesive 200, a linear polarizer 400, and a first glass surface 90. The linear polarizer 400 may be bonded to the first, second, third or fourth surface 202, 208, 210, and 204. The linear polarizer 400 may be aligned with the front polarizer 210 found in the LCD stack 80. The inclusion of a linear polarizer 400 in the front glass unit 206, further decreases the solar load on the LCD stack 80. The reduction in solar loading may significantly reduce the temperature of the electronic display.

[0052] The inclusion of the linear polarizer 400 may not affect the viewing angle of the electronic display or the chromaticity over angle. Another beneficial aspect of including the linear polarizer 400 is a reduction in specular reflection of the front glass unit 206 and the LCD stack 80 by approximately 50%.

[0053] Having shown and described preferred embodiments, those skilled in the art will realize that many variations and modifications may be made to affect the embodiments and still be within the scope of the claimed invention. Additionally, many of the elements indicated above may be altered or replaced by different elements which will provide the same result and fall within the spirit of the exemplary embodiments. It is the intention, therefore, to limit the invention only as indicated by the scope of the claims.