US20090126907A1

US20090126907A1 - Isolated Gas Heating System for an Electronic Display

Info

Publication number: US20090126907A1
Application number: US12/235,200
Authority: US
Inventors: William Dunn
Original assignee: Manufacturing Resources International Inc
Current assignee: Manufacturing Resources International Inc
Priority date: 2007-11-16
Filing date: 2008-09-22
Publication date: 2009-05-21

Abstract

A preferred embodiment relates to a heating system and a method for heating an electronic display. A preferred embodiment includes a transparent gas heat-transfer chamber which may be coexistent with the viewable display surface. The heating system defines two gas compartments that are anterior and posterior to the electronic display and are in gaseous communication. Fans may be used to propel the isolated gas through the two chambers. The circulating gas transfers heat to the electronic display surface by convection. The isolated gas is preferably transparent or at least semi-transparent.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional patent application and claims priority to U.S. Provisional Application No. 61/076,126 filed Jun. 26, 2008; 61/057,599 filed May 30, 2008; and 61/039,454 filed Mar. 26, 2008, which are hereby incorporated by reference in their entirety. This application is also a continuation in part of U.S. patent application Ser. No. 11/941,728 filed Nov. 16, 2007, which is hereby incorporated by reference in its entirety. This application is also a continuation in part of U.S. patent application Ser. No. 12/191,834 filed Aug. 14, 2008, which is hereby incorporated by reference in its entirety. This application is also a continuation in part of U.S. patent application Ser. No. 12/234,307 filed Sep. 19, 2008, which is hereby incorporated by reference in its entirety. This application is also a continuation in part of U.S. patent application Ser. No. 12/234,360 filed Sep. 19, 2008.

TECHNICAL FIELD

This invention generally relates to heating systems and in particular to a heating system and method for electronic displays.

BACKGROUND OF THE ART

In a typical electronic display, heat transfer systems typically seek to remove heat from the display. This may be done in any number of ways, but usually these systems generally attempt to remove heat from the electronic components in a display through sidewalls of the display housing.
When typical displays experience low temperatures, the heat transfer system is not adapted to maintain the heat of the display, or perhaps generate additional heat. This may be necessary, as low temperatures can cause a display to malfunction, not display images properly, or may permanently damage the display. Specifically for liquid crystal displays (LCDs), the crystal material may malfunction once the display experiences low temperatures. They crystal material may not respond appropriately to a potential difference and, in some cases, the crystal material may even freeze. Furthermore, although there may be some heat near the back of the display where the electrical components are, this heat has no way of contacting the area near the crystal material and thus heating the crystals.

SUMMARY OF THE INVENTION

Exemplary embodiments relate to an isolated gas heating system and a method for heating an electronic display. An exemplary embodiment includes an isolated gas heating chamber. The gas heating chamber is preferably a closed loop which includes a first gas chamber comprising a transparent anterior plate and a second gas chamber comprising a heating plenum. The first gas chamber is anterior to and coextensive with the viewable face of the electronic display surface. The transparent anterior plate may be set forward of the electronic display surface by spacers defining the depth of the first gas chamber.
A heating chamber fan, or equivalent means, may be located within the heating plenum. The fan may be used to propel gas around the isolated gas heating chamber loop. As the gas traverses the first gas chamber it contacts the electronic display surface, transferring heat to the front surface of the display. Because the gas and the relevant surfaces of the first gas chamber are transparent, the image quality remains excellent. After the gas has traversed the transparent first gas chamber, the gas may be directed into the rear heating plenum. In order to heat the gas in the plenum, heating elements may be used. In other embodiments, electronic components which operate the display may be placed within the heating plenum. These components naturally generate heat during operation, and can further heat the gas within the heating plenum. These components will also run more efficiently, if cool air is regularly circulated over them.
The foregoing and other features and advantages of the present invention will be apparent from the following more detailed description of the particular embodiments of the invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

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

FIG. 2 is an exploded perspective view of an exemplary embodiment showing components of the isolated gas heating system.

FIG. 3 is top plan view of an exemplary embodiment of the heating chamber.

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

FIG. 5 is a rear perspective view of an embodiment of the isolated heating chamber, particularly the heating plenum.

FIG. 6 is a schematic of several embodiments for heating elements.

DETAILED DESCRIPTION

Exemplary embodiments provide an isolated gas heating system for an electronic display.
FIG. 1 is an exemplary embodiment of the present invention. As may be appreciated, when the display 10 is exposed to cold temperatures and/or wind, the temperatures inside the display 10 will vary greatly without some kind of heating device, and may even drop below freezing. As such, the electronics including the display screen (e.g., LCD screen) may not function properly and may have a greatly reduced life span. By implementing certain embodiments of the heating system disclosed herein, temperature fluctuation is greatly reduced.
The display shown is equipped with an innovative gas heating system. Accordingly, it may be placed in environments which may experience low temperatures. Although the heating system may be used on any type of electronic display, it is especially useful for LCD displays.
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. Optionally, the display also may have a reflection shield 119, to mitigate reflection of any sunlight on the display surface. Additionally, if the display experiences very cold temperatures, especially in outdoor environments, housing 70 may be a color which absorbs sunlight.
It is to be understood that the spirit and scope of the disclosed embodiments includes heating of displays including, but not limited to LCDs. By way of example and not by way of limitation, the present invention 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 of the present invention may be used with displays of other types including those not yet discovered. In particular, it is contemplated that the present invention 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, coolers, freezers, frozen food processing plants) where thermal stability of the display may be at risk.
As shown in FIG. 2 an exemplary embodiment 10 of the electronic display and gas heating system includes an isolated gas heating 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 plate 90. If used with a LCD display, heating chamber 20 surrounds the LCD stack 80.
Referring to FIG. 3, in at least one embodiment the isolated gas heating chamber 20 comprises a closed loop which includes a first gas chamber 30 and a second gas chamber 40. The first gas chamber includes a transparent plate 90. The second gas chamber comprises a heating plenum 45. The term “isolated gas” refers to the fact that the gas within the isolated gas heating 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. 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.
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 heating 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.
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 heating chamber fan 50 may be provided within the posterior plenum 45. The heating fan 50 may be utilized to propel gas around the isolated gas heating chamber 20. The first gas chamber 30 includes at least one front glass 90 mounted in front of an electronic display surface 85. In an exemplary embodiment, the electronic display surface 85 may be adjacent to a LCD stack so that heat can easily transfer to the liquid crystal material. Optionally, the electronic display surface 85 may be the front portion of the LCD stack.
Referring now to FIG. 4, the front plate 90 may be set forward from the electronic display surface 85 by spacers 100. 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 100, 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.
The 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 heating gas directly to the electronic display surface 85 allows heat to transfer to the electronic display surface 85, and subsequently to the display stack 80. Accordingly, the term “electronic display surface” may refer 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.
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.
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 heating 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 or the front plate of a plasma display or the front plate of an OLED display. However, almost any display surface may be suitable for embodiments of the present heating system. Although not required, it is preferable to allow the heating 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 transferred heat to the electronic display surface 85 may then be diverted to the heating plenum 45 where it may absorb heat.
To prevent breakage, the optional second surface glass 130 may be adhered to the front surface of plate 90. Also, surface glass 130 may be heat tempered to improve its strength and may be coated with a polarizer. As shown in FIG. 3, fan 50 propels a current of air around the loop (see arrows) of the isolated gas heating chamber 20.
The plenum 45 defining the second gas chamber 40 is adapted to circulate the gas behind the electronic display assembly. Heating elements 200 may be located within the second gas chamber 40 and operate to warm the gas as it passes through the second gas chamber 40. These heating elements can be any one of the many commonly available heating elements. Many times, these elements are simply a material which contains a high electrical resistance, and thus generates heat when current flows through it. The heating elements can be, but are not limited to, any one of the following: nichrome wire or ribbon, screen printed metal/ceramic tracks deposited on ceramic insulated metal (generally steel) plates, CalRod (typically a fine coil of nichrome wire in a ceramic binder, sealed inside a tough metal shell), heat lamp, and Positive Thermal Coefficient (PTC) of resistance ceramic.
Additionally, the plenum 45 may contain electrical components 210 which power and control the electronic display. The electrical components may be any one of the following: transformers, microprocessors, printed circuit boards, resistors, capacitors, motors, wiring harnesses, and connectors. The electrical connections for the electrical components 210 may pass through a wall of the plenum 45. The electrical components 210 can be located anywhere within the plenum 45. The electrical components 210 may be mounted on the posterior or anterior surface of the plenum and may be mounted directly on the surface of the plenum or may be suspended by mounting posts so that gas may pass all around the component.
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 generally horizontal direction. Although heating 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.
As is clear from FIG. 4, to maximize the heating 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 heating plenum 45.
FIG. 5 shows a schematic of the rear heating 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 heating chamber. Whereas the first gas chamber 30 was designed to transfer heat from the gas to the front surface 85 of the display, the second gas chamber 40 is designed for the gas to absorb heat from either the heating elements 200, the electrical components 210, or both. Plenum 45 may have various contours and features to accommodate the internal structures within a given electronic display application.
It should be noted that two different types of heating elements are shown in the figures. However, a single type of heating element could be used in an exemplary embodiment. Alternatively, a combination of different types of heating elements could be used. Again, the specific type of heating element is entirely dependent upon the specific application, costs, size of the display, and surrounding environment. Several different types of CalRod heating elements are shown in FIG. 6. Obviously, these types of heating elements can take on almost any shape, and the designs which are shown are only exemplary and are not exhaustive.
In some embodiments, it may be advantageous to insulate the plenum walls, so that heat from the warm gas may not escape into the surrounding environment. This may be useful in situations where the temperature remains relatively cold throughout the operative life of the device, or perhaps when the display must temporarily experience very cold temperatures.
Furthermore, some electronic displays may be required to operate in a broad range of temperatures, i.e. from very hot to very cold. These displays may utilize both the heating system which is herein disclosed, as well as the cooling system disclosed in Co-pending application Nos. 61/033,064, Ser. No. 12/191,834, 61/053,713, 61/057,599, and 61/039,454. These embodiments may also contain the optional air curtain device, described in Co-pending application Ser. No. 11/941,728.
In some applications, the isolated gas heating system may run continuously while the display is operational. However, if desired, a temperature sensor (not shown) and a switch (not shown) may be incorporated. This thermostat may be used to detect when temperatures have reached a predetermined threshold value. In such a case, the isolated gas heating 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 kept within an acceptable temperature range.
Having shown and described preferred embodiments, those skilled in the art will realize that many variations and modifications may be made to affect the described 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.

Claims

1. A heating system for an electronic display having a display surface, the system comprising:

a first gas chamber positioned anterior to the electronic display surface;

a second gas chamber in gaseous communication with said first gas chamber;

a heating chamber fan within said second gas chamber to propel gas around the first and second gas chambers; and

means for heating the gas contained within the second gas chamber.

2. The system of claim 1, wherein:

the first gas chamber comprises a transparent anterior plate; and

the second gas chamber comprises a heating plenum.

3. The system of claim 2, wherein the first gas chamber further comprises

the electronic display surface;

spacers separating the electronic display surface and said transparent anterior plate; and

an entrance opening and an exit opening.

4. The system of claim 3, wherein:

the first gas chamber further comprises a second transparent anterior plate bonded to the first transparent anterior plate.

5. The system of claim 2, wherein:

the first gas chamber is adapted to transfer heat from the gas to the display surface.

6. The system of claim 2, wherein the means for heating the gas comprises heating elements.

7. The system of claim 1, wherein the means for heating the gas comprises electrical components.

8. The system of claim 1, further comprising:

a temperature sensing device within said first gas chamber;

a switch in communication with said temperature sensing device and said heating chamber fan; and

wherein the fan is switched on when the temperature within the first gas chamber reaches a threshold value.

9. The system of claim 6 wherein the plenum is thermally insulated.

10. The system of claim 1 wherein said fan runs continuously when the display is in operation.

11. The system of claim 1 further comprising a filter within the second gas chamber.

12. A heating system for an electronic display having a display surface, said system comprising:

a first gas chamber comprising

the display surface of the electronic display;

a transparent anterior plate separated from said display surface by spacers; and

an entrance and exit opening; and

a second gas chamber in gaseous communication with said first gas chamber,

said second gas chamber comprising

a heating plenum;

a heating chamber fan to propel gas around the first and second gas chambers; and

one or more heating elements.

13. The system from claim 12 further comprising one or more electrical components within the heating plenum.

14. The system from claim 12 further comprising a filter within said second gas chamber.

15. The system from claim 12 further comprising:

a temperature sensing device within said first gas chamber;

16. A method for heating an electronic display having a display surface with isolated gas, comprising the steps of:

providing an isolated gas system comprising a first gas chamber which is in contact with the electronic display surface and a second gas chamber comprising a heating plenum, wherein the first and second gas chambers are in gaseous communication;

forcing isolated gas into the first gas chamber;

transferring heat from the isolated gas to the electronic display surface;

directing the isolated gas into the heating plenum;

heating the isolated gas in the plenum; and

reintroducing the heated isolated gas into the first gas chamber.

17. The method of claim 16, wherein the heating step comprises the steps of:

providing one or more heating elements within said heating plenum;

forcing the isolated gas over said one or more heating elements; and

transferring heat from the heating elements to the isolated gas.

18. The method of claim 16, further comprising the steps of:

setting a threshold temperature for the isolated gas;

measuring the temperature of the isolated gas;

comparing the temperature of the isolated gas to the threshold temperature; and

heating the isolated gas only when the temperature of the isolated gas is less than the threshold temperature.

19. The method of claim 16, further comprising the step of filtering the isolated gas prior to forcing it into the first chamber.

20. The method of claim 16, further comprising the step of preventing a substantial amount of heat from escaping the second gas chamber.