Patent Application
20190212792
The embodiments described herein relate generally to a thermally resistive case for electronics. In particular, the disclosure relates to an accessory case for a cellular phone to protect against extreme fluctuations in environmental temperatures.
Users of electronic devices, such as cellular phones and tablet computers, may seek to protect their devices from impacts that frequently occur with such devices. As these devices become more powerful, they may produce increased amounts of heat. Heat exposure to certain components within the device, such as the battery, may decrease performance. In some instances, consumers may utilize an accessory case for their device to assist in dissipating or redirecting the heat produced from within the device. An example of such a case is shown in U.S. patent application Ser. No. 14/836,894.
However, cases for dissipating heat produced from within a device may be inadequate to protect against environmental conditions that can also adversely affect the device's performance. It is not uncommon for the average high and low temperatures in certain geographical regions to fall outside optimal operating ranges, and the use of electronic devices in these temperatures can decrease performance, such as battery life, or cause the device to enter a non-operating state. Other disadvantages of electronic devices and known accessory cases may exist.
The present disclosure is directed an accessory case for an electronic device that overcomes some of the problems and disadvantages discussed above.
An embodiment of an accessory case for an electronic device includes a shell, a first layer, and a second layer. The shell is shaped to selectively retain an electronic device. The second layer is positioned between the shell and the first layer, and has a higher thermal conductivity than the first layer. The first layer may comprise silicone and/or the second layer may comprise graphite. The first layer may include a polyester film. The graphite may have a thermal conductivity of 1400-1700 W/(m·K). The first layer may be bonded to the second layer by a pressure sensitive adhesive.
An embodiment of a method of assembling an accessory case for an electronic device comprising positioning a second layer between a shell and a first layer. The shell is shaped to selectively retain an electronic device. The second layer has a higher thermal conductivity than the first layer. The first layer may comprise silicone and/or the second layer may comprise graphite. The first layer may include a polyester film. The graphite may have a thermal conductivity of 1400-1700 W/(m·K). The method may include bonding the first layer to the second layer by a pressure sensitive adhesive.
An embodiment of an accessory case for an electronic communications device includes an interior volume, a shell, and a plurality of layers. The interior volume is shaped to receive an electronic communications device. The shell has sidewalls shaped to selectively retain the electronic communications device. The plurality of layers are positioned within the shell. The sidewalls and the plurality of layers define the interior volume. The plurality of layers include a thermally conductive material and a thermally resistive material, and the plurality of layers are positioned to limit a rate of heat transfer from the shell to the interior volume. The thermally conductive material may be graphite and the thermally resistive material may be silicone. The silicone may be positioned between the interior volume and the graphite.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the invention as defined by the appended claims.
First layer 120 is configured to thermally insulate electronic device 10 (shown in
Second layer 130 is configured to slow the rate of heat transfer to electronic device 10 (shown in
Third layer 140 may stiffen accessory case 100 and/or provide a more suitable material than shell 110 for adhesion of second layer 130. In some embodiments, third layer 140 comprises polycarbonate. The polycarbonate may have a thermal conductivity in the range of 0.19-0.22 W/(m·K). Third layer 140 includes a first side 141 and a second side 142 opposite first side 141. Third layer 140 may include an optics profile 143 to allow a camera and/or flash of electronic device 10 to be aligned with optics opening 113 of shell 110. Third layer 140 may include a lanyard fastener 145 with two slits 146. Lanyard fastener 145 facilitates connection of a lanyard (not shown) to accessory case 100.
As best seen in
Accessory case 100 passively regulates the temperature of electronic device 10. High or low environmental temperatures may be received to shell 110 of accessory case 100 and are passively transferred into the thermally conductive second layer 130. The heat is dissipated within second layer 130. First layer 120 prevents or limits thermal transfer to electronic device 10 from second layer 130. As the rate of heat transfer to electronic device 10 is slowed, electronic device 10 may stay within optimal operating temperatures for a longer period of time. For instance, low environmental temperatures against shell 110 of accessory case 100 may be dissipated into second layer 130 and the rate of temperature decrease of electronic device 10 may be slowed. Similarly, high environmental temperatures against shell 110 of accessory case 100 may be dissipated into second layer 130 and the rate of temperature increase of electronic device 10 may be slowed.
Additional tests compared the rate of heat transfer of an accessory case 100 with a thermally conductive second layer 130 of natural graphite and a thermally resistive first layer 120 of silicone positioned adjacent to electronic device 10 to an accessory case made of thermoplastic polyurethane (TPU). Table 2, below, shows the results of a test that was conducted using a 60° C. external heat source applied over thirty minutes. As shown, the use of natural graphite and silicone slowed the rate of heat transfer to electronic device 10. It is anticipated that the use of an artificial graphite, having a greater thermal conductivity, would be more efficient at limiting heat transfer to electronic device 10 than natural graphite.
Environmental temperatures 320 show extreme temperature fluctuations from a high environmental temperature 321 that exceeds upper operating limit 301 of electronic device 300 to a low environmental temperature 322 that is below lower operating limit 302 of electronic device 300. With an accessory case as disclosed herein, temperature curve 310 of electronic device 300 may fluctuate between a maximum device temperature 311 that does not exceed upper operating limit 301 and a minimum device temperature 312 that is above lower operating limit 302. It is recognized that maximum device temperature 311 and minimum device temperature 312 may depart outside operating temperature range 303 depending on the duration and intensity of environmental temperatures 320. Nevertheless, as illustrated in
A method includes assembling accessory case 100. The method include positioned second layer 130 between shell 110 and first layer 120. The method may include applying a pressure sensitive adhesive to bond first layer 120 and second layer 130. The method may include positioning third layer 140 between second layer 130 and shell 110. The method may include applying an additional layer of pressure sensitive adhesive over first layer 120 and second layer 130 for assembly with third layer 140 and/or shell 110. The method may include selectively retaining electronic device 10 within assembled accessory case 100.
Although this disclosure has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art, including embodiments that do not provide all of the features and advantages set forth herein, are also within the scope of this disclosure. Accordingly, the scope of the present disclosure is defined only by reference to the appended claims and equivalents thereof.
