CN110868823A - Housing assembly and electronics - Google Patents

Abstract

The application discloses casing subassembly and electron device. The housing assembly includes a chassis and a photonic crystal layer. The photonic crystal layer is disposed on the case. The photonic crystal layer includes first and second nonconductors that are periodically alternately stacked. The photonic crystal layer is used for reflecting light rays with a wave band of 0.2-2.5 mu m and improving the radiance of a wave band of 8-14 mu m. In the case assembly and the electronic device according to the embodiments of the present application, on one hand, the photonic crystal layer can selectively reflect light rays of a 0.2 μm-2.5 μm band concentrated by solar energy, thereby resisting heating of the electronic device by solar radiation; on the other hand, the photonic crystal layer can improve the radiance of 8-14 μm wave bands, and fully utilizes the passive radiation refrigeration of 8-14 μm wave bands, so that the effect of enhancing the infrared heat radiation effect is achieved, and the heat dissipation capacity of the electronic device is improved.

Description

Housing assembly and electronics

technical field

The present application relates to the technical field of heat dissipation of terminals, and more particularly, to a housing assembly and an electronic device.

Background technique

With the development of chips in electronic devices, the functions of the electronic devices are becoming more and more powerful, and accordingly, the power consumption of the electronic devices is also increasing. The high power consumption generated when the chip is running directly causes the temperature of the area where the chip is located to rise sharply. How to improve the heat dissipation capability of the electronic device has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

Embodiments of the present application provide a housing assembly and an electronic device.

The casing assembly of the embodiment of the present application includes a casing and a photonic crystal layer, the photonic crystal layer is disposed on the casing, and the photonic crystal layer includes a first non-conductor and a second non-conductor that are alternately stacked periodically, so the The photonic crystal layer is used for reflecting light in the band of 0.2 μm to 2.5 μm, and for improving the emissivity in the band of 8 μm to 14 μm.

The electronic device according to the embodiment of the present application includes a casing assembly and a functional element, the functional element is mounted on the casing assembly; the casing assembly includes a casing and a photonic crystal layer, and the photonic crystal layer is disposed on the casing assembly. On the chassis, the photonic crystal layer includes a first non-conductor and a second non-conductor that are alternately stacked periodically, and the photonic crystal layer is used to reflect light in the 0.2 μm to 2.5 μm band and to improve radiation in the 8 to 14 μm band Rate.

In the case assembly and the electronic device according to the embodiments of the present application, on the one hand, the photonic crystal layer can selectively reflect the light in the 0.2 μm to 2.5 μm band where the solar energy is concentrated, so as to resist the heating of the electronic device by solar radiation; The photonic crystal layer can improve the emissivity in the 8μm-14μm band, and make full use of the passive passive radiation cooling in the 8μm-14μm band, so as to enhance the effect of infrared heat radiation and improve the heat dissipation capacity of electronic devices.

Additional aspects and advantages of embodiments of the present application will be set forth, in part, in the following description, and in part will be apparent from the following description, or learned by practice of embodiments of the present application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic three-dimensional structure diagram of an electronic device according to some embodiments of the present application;

2 is a schematic plan view of an electronic device according to some embodiments of the present application;

3 is a schematic plan view of an electronic device according to some embodiments of the present application;

4 is a schematic structural diagram of a casing according to some embodiments of the present application;

5 is a schematic structural diagram of a housing assembly according to some embodiments of the present application;

6 is a schematic structural diagram of a housing assembly according to some embodiments of the present application;

7 is a schematic structural diagram of a photonic crystal layer according to some embodiments of the present application;

8 is a schematic structural diagram of a photonic crystal layer according to some embodiments of the present application;

9 is a schematic diagram of the solar radiation spectral energy distribution of certain embodiments of the present application;

10 is a schematic diagram of the transmittance of electromagnetic waves corresponding to multiple spectral ranges in certain embodiments of the present application when they pass through the atmosphere;

11 is a schematic diagram of the optical properties of the photonic crystal layer of some embodiments of the present application;

12 is a schematic diagram of energy flow corresponding to radiant cooling capacity in some embodiments of the present application;

13 is a schematic diagram of the net radiative cooling power of the photonic crystal layer of certain embodiments of the present application as a function of equilibrium temperature;

14 is a schematic diagram of the equilibrium temperature of the photonic crystal layer of certain embodiments of the present application as a function of heat transfer coefficient.

Detailed ways

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, only used to explain the present application, and should not be construed as a limitation on the present application.

In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " rear, left, right, vertical, horizontal, top, bottom, inside, outside, clockwise, counterclockwise, etc., or The positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, Therefore, it should not be construed as a limitation on this application. In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined as "first", "second" may expressly or implicitly include one or more of said features. In the description of the present application, "plurality" means two or more, unless otherwise expressly and specifically defined.

In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; it can be mechanical connection, electrical connection or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction of two elements relation. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are only examples and are not intended to limit the application. Furthermore, this application may repeat reference numerals and/or reference letters in different instances for the purpose of simplicity and clarity, and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. In addition, this application provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

As the power consumption of mobile phones increases, the heat dissipation of mobile phones has become a key factor limiting the performance of mobile phones. The particularity of mobile phone heat dissipation is that it is necessary to ensure that the temperature of the chip is reduced (that is, the heat of the chip can be dissipated through materials with low thermal resistance/high thermal conductivity), and the temperature of the back cover of the mobile phone must be reduced (that is, through thermal insulation structure design or thermal insulation. The material reduces the conduction of heat from the phone chip to the phone back cover). However, these two requirements are contradictory in terms of heat dissipation. To reduce the temperature of the chip, it is necessary to export the heat to the back cover faster, which will cause the temperature of the back cover to rise; if you want to reduce the temperature of the back cover , and the heat must be confined inside the phone, which in turn causes the temperature of the chip to rise.

In order to meet the heat dissipation requirements of mobile phones, the current technical direction is usually: spread the heat as much as possible inside the mobile phone, make full use of the surface area of the mobile phone to dissipate heat, eliminate local hot spots on the back cover of the mobile phone, and ensure the working temperature of the chip while reducing as much as possible. The temperature of the back cover of the phone. From a physical point of view, heat spreads in three ways, namely conduction, convection, and radiation. Due to the limitation of the size of mobile phones, convection is difficult to use (convection requires gas flow, that is, a fan, and it is difficult to design a fan structure inside the mobile phone), so two methods of conduction and radiation are considered. In these two methods, the conduction is to homogenize the heat (such as graphene, vapor chamber (VC), heat pipe, etc.), and the heat can be transferred to the back cover of the mobile phone through the chip and dissipated. . The heat dissipation effect of thermal radiation is slightly weaker than that of conduction, but due to the small gap between the internal structures of the mobile phone and the large radiation angle coefficient, thermal radiation also plays a crucial role in the heat dissipation of the mobile phone.

At present, a large number of technologies are using heat conduction to reduce the junction temperature of mobile phone chips and the temperature of the back cover of mobile phones, such as synthetic graphite, graphene, VC, heat pipes, etc. The principle of synthesizing graphite and graphene is to use the high thermal conductivity (usually >1000W/mK) of the graphene material in the plane to homogenize the heat and eliminate local hot spots. The principle of VC is the same as that of heat pipe, both of which use the phase change of pure water to improve the heat soaking ability, which has a larger heat flux (ie, antipyretic ability) than synthetic graphite and graphene.

The current solutions are basically limited to the traditional heat dissipation method, that is, heat dissipation through the path of "chip-shield cover-mobile phone case-environment". The dimensionless number that measures the heat dissipation capability of a mobile phone is the coefficient of thermal spreading (CTS). The closer the CTS is to 1, the better the heat dissipation capability of the mobile phone. At present, the CTS of mobile phones with better heat dissipation has reached more than 0.85, which is basically close to the limit. Therefore, the traditional heat dissipation path has reached the bottleneck and cannot further reduce the temperature of the mobile phone.

Referring to FIGS. 1 and 2 , embodiments of the present application provide an electronic device 1000 and a housing assembly 100 .

Referring to FIG. 1 , an electronic device 1000 according to an embodiment of the present application includes a housing assembly 100 and a functional element 200 . The electronic device 1000 may be a mobile phone, a tablet computer, a laptop computer, a smart bracelet, a smart watch, a smart helmet, a smart glasses, and the like. The embodiments of the present application are described by taking the electronic device 1000 as a mobile phone as an example. It can be understood that the specific form of the electronic device 1000 is not limited to a mobile phone.

The functional element 200 is mounted on the housing assembly 100 , that is, the housing assembly 100 can serve as a mounting carrier for the functional element 200 . The housing assembly 100 can provide protection against dust, drop, and water for the functional element 200 . The functional element 200 may be a display screen, a camera, a receiver, a chip, and the like.

Referring to FIG. 2 and FIG. 3 , the housing assembly 100 of the embodiment of the present application includes a housing 20 and a photonic crystal layer 14 .

The casing 20 may be the back cover of the electronic device 1000 . For example, when the electronic device 1000 is a mobile phone, the casing 20 is the back cover of the mobile phone. The photonic crystal layer 14 is provided on the casing 20 .

Referring to FIGS. 3 to 5 , in one example, the housing 20 may include an inner surface 21 and an outer surface 22 that are opposed to each other. Wherein, the inner surface 21 may be formed with a accommodating cavity 212 for accommodating the functional element 200 .

The photonic crystal layer 14 is disposed on the outer surface 22 . Specifically, the photonic crystal layer 14 may be formed on the outer surface 22 by a chemical vapor deposition (Chemical Vapor Deposition, CVD) method. The chemical vapor deposition method can obtain a coating with high purity, good density and good crystallization (ie, the photonic crystal layer 14 ), and the photonic crystal layer 14 has strong adhesion on the outer surface 22 and is not easy to fall off.

Referring to FIG. 6 , in another example, the casing 20 may include a cover 23 and a light-transmitting protective layer 24 . The cover body 23 includes a first inner surface 231 and a first outer surface 232 which are opposite to each other. The protective layer 24 includes a second inner surface 241 and a second outer surface 242 that are opposite to each other. The first outer surface 232 is opposite to the second inner surface 241 . Wherein, the first inner surface 231 may be formed with an accommodation chamber (not shown) for accommodating the functional element 200 . The protective layer 24 can be protective glass, which has the advantages of high hardness, not easy to scratch, beautiful appearance, low cost, etc., and has a good hand feeling, which is beneficial to improve the user's experience of holding the casing 20 .

The photonic crystal layer 14 is located between the first outer surface 232 and the second inner surface 241 . Specifically, the photonic crystal layer 14 may be disposed on the first outer surface 232 or on the second inner surface 241 . Preferably, the photonic crystal layer 14 can be disposed on the first outer surface 232 , so that when the protective layer 24 is peeled off or damaged, the photonic crystal layer 14 can still function on the cover body 23 . The photonic crystal layer 14 may be formed on the first outer surface 232 by chemical vapor deposition. The chemical vapor deposition method can obtain a coating with high purity, good compactness and good crystallization (ie, the photonic crystal layer 14 ), and the photonic crystal layer 14 has strong adhesion on the first outer surface 232 and is not easy to fall off.

In the embodiment of the present application, since the protective layer 24 is light-transmitting, the function of reflecting light of the photonic crystal layer 14 is basically not affected (which will be described in detail later), and the photonic crystal layer 14 is located between the cover body 23 and the protective layer 24 Meanwhile, the protective layer 24 can also play a certain protective role on the photonic crystal layer 14, for example, preventing the photonic crystal layer 14 from being scratched or the photonic crystal layer 14 from falling off.

It can be understood that, for the electronic device 1000 , the power consumption generated by the chip during operation is generally high, and the heat generated is also relatively large, so the photonic crystal layer 14 can be further disposed on the casing 20 at a position corresponding to the chip (for example, the outer surface of the chip). 22 corresponding to the chip, or the first outer surface 232 corresponding to the chip), so as to fully dissipate the heat generated by the chip, and the casing 20 of the electronic device 1000 will not have a problem of local overheating. In addition, the planar area of the photonic crystal layer 14 covering the outer surface 22 or the first outer surface 232 may be larger than the area of the chip, so as to further improve the heat dissipation effect. Of course, the photonic crystal layer 14 may also cover the entire outer surface 22 or the first outer surface 232 , and the photonic crystal layer 14 cooperates with the design of the casing 20 to ensure the heat dissipation effect of the electronic device 1000 .

Referring to FIG. 7 and FIG. 8 , the photonic crystal layer 14 includes a first non-conductor 141 and a second non-conductor 142 that are alternately stacked periodically. The photonic crystal layer 14 is used for reflecting light in the band of 0.2 μm to 2.5 μm, and for improving the emissivity in the band of 8 μm to 14 μm.

In the case assembly 100 and the electronic device 1000 according to the embodiments of the present application, on the one hand, the photonic crystal layer 14 can selectively reflect the light in the 0.2 μm-2.5 μm band where the solar energy is concentrated, thereby resisting the heating of the electronic device 1000 by solar radiation On the other hand, the photonic crystal layer 14 can improve the emissivity in the 8 μm to 14 μm band, and make full use of the passive passive radiation cooling in the 8 μm to 14 μm band, so as to enhance the effect of infrared heat radiation and improve the heat dissipation capability of the electronic device 1000 .

Referring to FIGS. 7 and 8 , the photonic crystal layer 14 includes first non-conductors 141 and second non-conductors 142 that are periodically alternately stacked along a predetermined direction. The predetermined direction may be the direction from the outer surface 22 to the inner surface 21 of the casing 20 (or the direction from the second outer surface 242 to the first inner surface 231 ), or the thickness direction of the electronic device 1000 . In the embodiment of the present application, the photonic crystal layer 14 adopts a photonic crystal structure in which the first non-conductor 141 and the second non-conductor 142 are alternately stacked periodically as a reflective layer to provide high reflection characteristics of the solar spectrum.

The photonic crystal layer 14 is used for reflecting light in the wavelength band of 0.2 μm˜2.5 μm. That is to say, the wavelength of light reflected by the photonic crystal layer 14 is any value between 0.2 μm and 2.5 μm. For example, the wavelengths of light reflected by the photonic crystal layer 14 are 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.5 μm, etc. . In the embodiment of the present application, the photonic crystal layer 14 can selectively reflect the light in the band of 0.2 μm˜2.5 μm where the solar energy is concentrated, so as to resist the heating of the electronic device 1000 by solar radiation.

The photonic crystal layer 14 is also used to improve the emissivity in the 8 μm-14 μm band (the emissivity of the casing 20 of the electronic device 1000 in the 8 μm-14 μm band can be improved). That is, the wavelength used by the photonic crystal layer 14 to increase the emissivity is any value between 8 μm and 14 μm. For example, the wavelengths used by the photonic crystal layer 14 to increase the emissivity are 8 μm, 8.6 μm, 9.2 μm, 9.8 μm, 10.4 μm, 11 μm, 11.6 μm, 12.2 μm, 12.8 μm, 13.4 μm, 14 μm, and the like. In the embodiment of the present application, the photonic crystal layer 14 can improve the emissivity in the 8 μm-14 μm band, and make full use of the passive passive radiation cooling in the 8 μm-14 μm band, so as to enhance the effect of infrared heat radiation and improve the heat dissipation capability of the electronic device 1000 . .

It is understandable that there are more and more scenarios in which mobile phones are used outdoors. The heat dissipation of mobile phones not only needs to consider the thermal power consumption of the internal chip, but also the heating effect of solar radiation on the mobile phone has gradually become a factor for the overheating of the mobile phone. The solar spectral characteristics of standard air mass (AM) 1.5 are similar to the black body radiation spectrum with a temperature of 5762K, the total radiation is about 1000W/m ² , and 99% of its energy is concentrated in the short-wave region of 0.2 μm to 2.5 μm. The greenhouse effect is due to the fact that glass has a high penetration ratio for thermal radiation with a wavelength below 3 μm, and the penetration ratio of thermal radiation with a wavelength greater than 3 μm decreases suddenly, so most of the solar radiation can pass through the glass and enter the chamber, while the cavity The long-wave radiation emitted by the chamber is blocked in the chamber, causing the temperature inside the chamber to rise.

In the embodiment of the present application, for the casing 20 of the electronic device 1000 (such as the back cover of a mobile phone), the photonic crystal layer 14 selectively reflects the light in the 0.2 μm-2.5 μm band (reflecting most of the solar radiation) where the solar energy is concentrated. , so as to prevent solar radiation from heating the casing 20 of the electronic device 1000 and prevent the electronic device 1000 from overheating due to the solar radiation heating the casing 20 of the electronic device 1000 . At the same time, the emissivity or emissivity of the 8μm-14μm band is increased through the photonic crystal layer 14, and the excess heat is transmitted to outer space without consuming any energy by using the atmospheric window, so as to realize passive selective radiation cooling.

The number of cycles in which the first non-conductor 141 and the second non-conductor 142 are alternately stacked may be greater than or equal to five. That is, the number of periods in which the first non-conductor 141 and the second non-conductor 142 are alternately stacked periodically is an arbitrary value greater than or equal to five. For example, the number of periods in which the first non-conductor 141 and the second non-conductor 142 are alternately stacked periodically is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and so on. Taking the cycle number of the first non-conductor 141 and the second non-conductor 142 alternately stacked as 5 as an example, the sequence in the predetermined direction is: the first non-conductor 141, the second non-conductor 142, the first non-conductor 141, the second non-conductor Conductor 142 , first non-conductor 141 , second non-conductor 142 , first non-conductor 141 , second non-conductor 142 , first non-conductor 141 , second non-conductor 142 , outer surface 22 . When the number of periods in which the first non-conductor 141 and the second non-conductor 142 are alternately stacked is greater than or equal to 5, the photonic crystal layer 14 can have a better reflection effect and have high reflection characteristics for the solar spectrum.

Preferably, the number of cycles in which the first non-conductor 141 and the second non-conductor 142 are alternately stacked periodically is ten. In this way, the relationship between the thickness of the photonic crystal layer 14 and the reflection effect of the photonic crystal layer 14 on the solar spectrum can be balanced, that is, the photonic crystal layer 14 has a smaller thickness and a better reflection effect on the solar spectrum at the same time. . It can be understood that when the number of periods of alternately stacking the first non-conductor 141 and the second non-conductor 142 is small, the photonic crystal layer 14 may not be able to achieve a better reflection effect on the solar spectrum; when the first non-conductor 141 and the second non-conductor 142 When the number of periods in which the conductors 142 are alternately stacked is large, the photonic crystal layer 14 may be thicker. When the photonic crystal layer 14 is disposed on the casing 20 , the appearance and practicability of the electronic device 1000 will be affected, and user experience will be affected.

Referring to FIG. 7 , in one example, the first non-conductor 141 is titanium dioxide (TiO), and the second non-conductor 142 is silicon dioxide (TiO). At this time, titanium dioxide and silicon dioxide are periodically stacked in a predetermined direction, that is to say, the order in the predetermined direction is: titanium dioxide, silicon dioxide, titanium dioxide, silicon dioxide, . . . , titanium dioxide, silicon dioxide, and the casing 20 .

Referring to FIG. 8 , in another example, the first non-conductor 141 is silicon dioxide, and the second non-conductor 142 is titanium dioxide. At this time, silicon dioxide and titanium dioxide are periodically stacked in a predetermined direction, that is to say, the order in the predetermined direction is: silicon dioxide, titanium dioxide, silicon dioxide, titanium dioxide, ..., silicon dioxide, titanium dioxide, casing 20 .

It should be pointed out that the titanium dioxide and silicon dioxide in the above-mentioned embodiments both adopt nano-scale structures, that is, nano-layers of titanium dioxide and nano-layers of silicon dioxide. In addition, since the materials used in the first non-conductor 141 and the second non-conductor 142 do not involve conductors, they will not affect the antenna signal transmission of the electronic device 1000 , which is convenient for application in the electronic device 1000 with an antenna.

The thickness of the photonic crystal layer 14 (the total thickness of the first non-conductor 141 and the second non-conductor 142 that are periodically alternately stacked) may be greater than or equal to 6 μm. That is, the thickness of the photonic crystal layer 14 is any value greater than or equal to 6 μm. For example, the thickness of the photonic crystal layer 14 is 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, and the like. When the thickness of the photonic crystal layer 14 is greater than or equal to 6 μm, the thickness of the single-layer first non-conductor 141 and the single-layer second non-conductor 142 will not be too thin, which facilitates process manufacturing and ensures product yield and reflection effect.

The principle and effect of the photonic crystal layer 14 in the embodiment of the present application will be described in detail below with reference to FIGS. 9 to 14 .

The solar radiation spectral energy distribution is shown in Figure 9. Most of the energy is concentrated between 0.2μm and 2.5μm, that is, the influence of solar radiation on the temperature of the object is mainly determined by the radiation capacity in this wavelength range. Based on the AM1.5 solar spectrum, the total energy of solar radiation is 1000W/m ² , this will be a huge energy consumption for refrigeration technology. The embodiment of the present application blocks light in the wavelength range of 0.2 μm˜2.5 μm from outside the casing 20 of the electronic device 1000 through the selective reflection effect of the photonic crystal layer 14 to eliminate the heating effect of solar radiation on the casing 20 . The reason for selecting the photonic crystal layer 14 is that the photonic crystal structure can use the alternate stacking of multiple layers of non-conductors to achieve the effect of the metal reflective layer, which avoids the interference of the metal reflective layer on the antenna of the electronic device 1000 , and makes the casing 20 of the electronic device 1000 . The design and use are more convenient.

The embodiment of the present application also utilizes the atmospheric window to fully utilize the radiation heat dissipation of the casing 20 of the electronic device 1000 . The atmospheric window refers to the spectral band with high transmittance when electromagnetic waves pass through the atmosphere. As shown in Figure 10, atmospheric windows exist in multiple spectral ranges. Among them, 8μm～14um is the thermal infrared band, and the peak wavelength of thermal radiation of objects on the earth is usually distributed in this band. High transmittance (>80%) and low absorption. Therefore, objects on the earth can use the atmospheric window band of 8 μm to 14 μm to dissipate heat into outer space in the form of electromagnetic waves through radiation cooling, and realize passive passive radiation cooling.

In the embodiment of the present application, the infrared thermal radiation characteristics of the material are controlled by the photonic crystal structure (ie, the photonic crystal layer 14 ), and the performance of the electronic device 1000 is improved without using a metal reflective layer to avoid interference to the antenna signal transmission of the electronic device 1000 . The reflectivity of the shell 20 in the solar spectrum, and the high emissivity in the whole wavelength range of 8 μm to 14 μm is realized. The optical properties of the photonic crystal layer 14 are shown in FIG. 11 . The photonic crystal layer 14 has an average reflectivity of 97% in the solar spectrum band of 0.2 μm to 2.5 μm, basically does not absorb solar radiation energy, and has an average emissivity of 90% in the atmospheric window band, which can realize passive radiation cooling through the atmospheric window.

In the following, the concept of radiative cooling capacity is introduced to illustrate the effect of the photonic crystal layer 14 in the embodiment of the present application on the temperature. The calculation of radiative cooling capacity can be represented by the energy flow shown in Figure 12. Among them, q _rad is the radiant energy of the radiator, q _sun is the solar radiation absorbed by the radiator, q _sky is the atmospheric radiation absorbed by the radiator, and q _loss is the inherent heat loss (such as static air convection, air heat conduction, etc.). The calculation of radiation cooling capacity satisfies the following formula, q _net-cooling is the radiation cooling capacity. For example, for a clear sky environment with low humidity, when the ambient temperature is 300K, the net radiative cooling power of objects on earth can be as high as 140W/m ² , which only considers the radiation amount of objects in the atmospheric window.

q _net-cooling = q _rad (T _r ) - q _sky - q _sun - q _loss .

Based on the above formula, without considering the influence of non-radiative factors, the change of the net radiative cooling power of the photonic crystal layer 14 with the ambient temperature is theoretically calculated, and the effect is shown in FIG. 13 . As can be seen from FIG. 13 , at a room temperature of 300K, the theoretical value of the net radiation cooling power of the photonic crystal layer 14 can reach 119.6 W/m ² . For comparison, if the photonic crystal layer 14 of the embodiment of the present application is not used, the theoretical value of the net radiative cooling power is -861.4 W/m ² , that is, the temperature will gradually increase due to the absorption of sunlight energy.

As the temperature increases, the net radiative capacity increases. At the same time, the function realized by the photonic crystal layer 14 is passive passive radiation cooling. When considering the cooling effect, its own radiation heat dissipation capacity will be considered, and the equilibrium temperature of the photonic crystal layer 14 will be considered, that is, the photonic crystal layer can be cooled by spontaneous radiation. 14 The lowest temperature that can be reached. At the same time, considering the practicability, it is necessary to consider the influence of the power loss of the photonic crystal layer 14 itself on the cooling efficiency of the photonic crystal layer 14. The relationship between the equilibrium temperature and the heat transfer coefficient that the theoretical photonic crystal layer 14 can achieve when the ambient temperature is 300K As shown in Figure 14. It can be seen from Fig. 14 that when the heat loss is not considered, the photonic crystal layer 14 can achieve a cooling effect of about 38K lower than the ambient temperature. As the heat transfer coefficient increases, considering the actual working conditions (the convective heat transfer coefficient is about 6W) /m ² K), it can also achieve a cooling effect of about 12.7K.

To sum up, in the embodiment of the present application, the photonic crystal layer 14 is added on the casing 20 of the electronic device 1000 to achieve the functions of selectively enhancing the reflection of the solar spectrum and improving the emissivity of the atmospheric window, and eliminating the possibility that the electronic device 1000 is susceptible to solar radiation And overheating, and the heat cannot be dissipated by radiation. In addition, the materials used for the photonic crystal layer 14 do not involve conductors, and the antenna interference caused by traditional metal plating layers can also be effectively avoided.

In the description of this specification, reference is made to the terms "some embodiments", "one embodiment", "some embodiments", "exemplary embodiment", "example", "one Or the description of "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features delimited with "first", "second" may expressly or implicitly include at least one of said features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations of the present application, and those of ordinary skill in the art can perform the above embodiments within the scope of the present application. Variations, modifications, substitutions and alterations, the scope of this application is defined by the claims and their equivalents.

Claims (10)

1. A housing assembly, characterized in that, the housing assembly comprises: enclosure; and A photonic crystal layer, the photonic crystal layer is disposed on the casing, the photonic crystal layer includes a first non-conductor and a second non-conductor that are alternately stacked periodically, and the photonic crystal layer is used for reflecting 0.2 μm to 2.5 μm It is used to increase the radiance in the 8μm to 14μm band. 2. The housing assembly of claim 1, wherein the first non-conductor is silicon dioxide and the second non-conductor is titanium dioxide; or The first non-conductor is titanium dioxide, and the second non-conductor is silicon dioxide. 3 . The housing assembly according to claim 1 , wherein the number of cycles in which the first non-conductor and the second non-conductor are alternately stacked is greater than or equal to 5. 4 . 4 . The housing assembly according to claim 3 , wherein the number of cycles in which the first non-conductor and the second non-conductor are alternately stacked is 10. 5 . 5 . The housing assembly according to claim 1 , wherein the thickness of the photonic crystal layer is greater than or equal to 6 μm. 6 . 6. The housing assembly of claim 1, wherein the housing comprises an inner surface and an outer surface that are opposite to each other, and the photonic crystal layer is disposed on the outer surface. 7. The housing assembly of claim 6, wherein the photonic crystal layer is formed on the outer surface by a chemical vapor deposition method. 8 . The housing assembly according to claim 1 , wherein the housing comprises a cover body and a light-transmitting protective layer, the cover body comprising a first inner surface and a first outer surface opposite to each other, the The protective layer includes an opposite second inner surface and a second outer surface, the first outer surface is opposite to the second inner surface, and the photonic crystal layer is located on the first outer surface and the second inner surface between the surfaces. 9. The housing assembly of claim 8, wherein the photonic crystal layer is formed on the first outer surface by a chemical vapor deposition method. 10. An electronic device, characterized in that the electronic device comprises: The housing assembly of any one of claims 1 to 9; and a functional element mounted on the housing assembly.

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