Abstract:
Disclosed are a display screen film and a preparation method therefor, and an energy saving method. The display screen film comprises an oriented carbon nanotube layer and a quartz glass layer, wherein the oriented carbon nanotube layer is located above the quartz glass layer, comprises an oriented growth carbon nanotube, and is configured to refract all incident light through the oriented growth carbon nanotube; the quartz glass layer is used for the carbon nanotube layer to grow orientately thereon, and is also used for absorbing the incident light so as to enable all the incident light to reach the oriented carbon nanotube layer.

Description:
TECHNICAL FIELD 
     The disclosure relates to the optical film energy saving technology, and in particular to a display screen film, a preparation method therefor and an energy saving method therewith. 
     BACKGROUND 
     At present, the development of electronic consumer goods has entered the intelligent big-display screen times; for example, users no longer are limited to making a call and sending a short message when using a mobile terminal such as mobile phone; more abundant applications lie in other functions of mobile terminal, for example, watching a video, taking a photograph, seeing blogs, chatting, navigation and so on. Using the mobile terminal having a big-display screen, users have a better visual effect and acquire more information; however, the endurance capability becomes the most important index for the performance of a mobile terminal. 
     At present, the screen of the mobile terminal with a big-display screen is of above 4 inches generally; most manufacturers need to provide a battery of at least 1500 mAh to maintain one-day usage of the mobile terminal, and a tablet computer needs to be provided with a higher-capacity battery. However, existing battery material limits the continuous increment of capacity; therefore, in order to save energy, optimization can be made to the screen of these electronic products. 
     The brightness of screen is an important part for energy consumption of an electronic product; specifically, the screen in standby mode and display mode will consume about 40% electricity; therefore, it is needed to optimize the brightness of screen, i.e., reduce the display brightness; however, this method is unbeneficial for users, only good display through a screen can let users&#39; eyes watch comfortably and thus good usage experience can be ensured; therefore, the brightness cannot be reduced too much; in this way, energy saving need to be realized through a novel technology. 
     SUMMARY 
     In order to solve the above technical problem, the embodiments of the disclosure provide a display screen film, a preparation method therefor and an energy saving method therewith. 
     An embodiment of the disclosure provides a display screen film, including: a quartz glass layer and an orientated carbon nanotube layer, in which: 
     the orientated carbon nanotube layer is located on the quartz glass layer, comprises orientated grown carbon nanotubes and is configured to refract all incident light through the orientated grown carbon nanotubes; and 
     the quartz glass layer is configured to enable the orientated carbon nanotube layer to grow on it and is used configured to absorb incident light and enable all the incident light to reach the orientated carbon nanotube layer. 
     An embodiment of the disclosure also provides a preparation method for a display screen film, including: 
     an orientated carbon nanotube layer is grown on a quartz glass layer; 
     the quartz glass layer absorbs incident light and enabling all the incident light to reach the orientated carbon nanotube layer, and the orientated carbon nanotube layer refracts all incident light. 
     In an embodiment, the orientated carbon nanotube layer may be grown on the quartz glass layer using hydrogen-free chemical vapour deposition. 
     In an embodiment, carbon nanotubes of the orientated carbon nanotube layer may have orientated growth directions of 90°±15°. 
     In an embodiment, growing the orientated carbon nanotube layer on the quartz glass layer may be: vertically growing, on the quartz glass layer, carbon nanotubes for refracting all incident light. 
     In an embodiment, gaps between carbon nanotubes on the oriented carbon nanotube layer may have a size in the range of 400 nm to 700 nm. 
     In an embodiment, carbon nanotubes on the oriented nanotube layer may have a diameter in the range of 20 nm to 80 nm. 
     An embodiment of the disclosure further provides an energy saving method for a display screen film, including: 
     an orientated carbon nanotube layer is grown on a quartz glass layer; 
     the quartz glass layer having the orientated carbon nanotube layer grown thereon is formed into a display screen film and the display screen film is attached onto the surface of a display screen; the quartz glass layer absorbs the incident light from the surface of the display screen and enabling all the incident light to reach the orientated carbon nanotube layer; the orientated carbon nanotube layer refracts all the incident light and enables the light to emit out vertically after passing through the display screen film. 
     According to the display screen film, preparation method therefor and energy saving method therewith provided by the embodiments of the disclosure, an orientated carbon nanotube layer is grown on a quartz glass layer, so that the quartz glass layer can absorb incident light and enable all the incident light to reach the orientated carbon nanotube layer, and that the orientated carbon nanotube layer can refract all incident light absorbed by the quartz glass layer, thereby the light is enabled to emit out vertically after passing through the film, and energy is saved. 
     The quartz glass layer having the orientated carbon nanotube layer grown thereon is formed into a display screen film and attached onto the surface of a display screen, so that the quartz glass layer can absorb the incident light from the surface of the display screen and enable all the incident light to reach the orientated carbon nanotube layer; correspondingly, the orientated carbon nanotube layer can refract all the incident light and enable the light to emit out vertically after passing through the display screen film. In this way, energy saving can be achieved while brightness is not reduced and the endurance capability of mobile terminal can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural diagram of a display screen film according to an embodiment of the disclosure; 
         FIG. 2  is an effect diagram showing an action of a display screen film according to an embodiment of the disclosure; and 
         FIG. 3  is a comparison diagram showing situations with or without a display screen film according to the embodiment of the disclosure applied onto a display screen. 
     
    
    
     DETAILED DESCRIPTION 
     At present, people use electronic products more and more frequently; battery capacity is the foundation for the endurance capability of electronic products; conventional battery development technology focuses on the material of battery, however, the breakthrough of new material has its own bottleneck. If, in another view, to change the original omni-directional 180-degree visual angle of light to a smaller scope almost perpendicular to a display screen, then in the condition that the whole screen brightness is reduced to ⅓ of the original brightness, users can percept a same brightness in the vertical angle of view as when the brightness is not reduced; in this way, the effect of energy saving of electronic products can be implemented from another way. 
     Based on the above consideration, the basic idea of the embodiment of the disclosure lies in: an orientated carbon nanotube layer is grown on a quartz glass layer; the quartz glass layer having the orientated carbon nanotube layer grown thereon is formed into an energy-saving display screen film and the display screen film is attached onto the surface of a display screen, so that the quartz glass layer absorbs the incident light from the surface of the display screen, and all the incident light is enabled to reach the orientated carbon nanotube layer; correspondingly, the orientated carbon nanotube layer refracts all the incident light, thus the light is enabled to emit out vertically after passing through the film. 
     Orientated grown carbon nanotubes of the orientated carbon nanotube layer grow vertically, so as to reduce the refraction light loss for the incident light from different angles; the quartz glass layer can ensure that the incident light absorbed from the display screen is made to reach the orientated carbon nanotube layer. 
     Here, the quartz glass layer has a strong transmission enhancement effect; therefore, the light emitted from the surface of the display screen has no loss when reaching gaps between the carbon nanotubes after passing through the quartz glass layer. 
     Here, the display screen might be a liquid crystal display. 
     The display screen film provided by the embodiment of the disclosure, as shown in  FIG. 1 , includes: a quartz glass layer  11  and an orientated carbon nanotube layer  12 , in which: 
     the orientated carbon nanotube layer  12  is located on the quartz glass layer  11 , includes at least one orientated grown carbon nanotube and is configured to refract all incident light through the at least one orientated grown carbon nanotube; 
     the quartz glass layer  11  is configured to enable the orientated carbon nanotube layer  12  to grow on it, and is configured to absorb incident light and enable all the incident light to reach the orientated carbon nanotube layer  12 . 
     Corresponding to the display screen film shown in  FIG. 1 , the embodiment of the disclosure also provides a preparation method for the film, including the following steps: an orientated carbon nanotube layer is grown on a quartz glass layer; the quartz glass layer absorbs incident light and enables all the incident light to reach the orientated carbon nanotube layer; and the orientated carbon nanotube layer refracts all the incident light. 
     Here, the orientated carbon nanotube layer may be grown on the quartz glass layer using hydrogen-free chemical vapour deposition; the growth means vertical growth on the quartz glass layer. 
     For example, Fe(C 5 H 5 ) 2  is taken as a catalyst, acetylene as a carbon source, nitrogen as carrier gas, the ratio between the amount of the catalyst and the flow rate of the carbon source is about 1 g:100 mL/min, the flow rate ratio between the carrier gas and the carbon source is N 2 :C 2 H 2 =2:1 to 4:1, the total flow rate of gas does not exceed 300 mL/min. 
     An existing quartz glass layer is taken as a substrate and it is put into a multi-temperature area horizontal column reactor, where a quartz tube is taken as a reaction chamber, and nitrogen (carrier gas) and acetylene (carbon source) arrive at two tube inlets of the reactor respectively. 
     The temperature of the reactor is increased, and when the reaction temperature increases to 700-800 degrees centigrade, the nitrogen and acetylene are directed into the reaction chamber with a flow rate of 100-300 mL/min for the nitrogen and a flow rate of 40-100 mL/min for the acetylene. 
     The morphology of the orientated carbon nanotube layer can be observed and analysed by a scanning electron microscope; when carbon nanotubes of the grown orientated carbon nanotube layer form columns with an orientated growth direction of 90 plus/minus 15 degrees; the supply of the carbon source is cut off first and then the supply of the carrier gas is cut off, and the temperature is reduced to the normal temperature, and then the quartz glass layer with the orientated carbon nanotube layer grown thereon is taken out. 
     The orientated growth directions of the carbon nanotubes are between 75 degrees and 105 degrees. These carbon nanotubes are arranged on the substrate with directivity; carbon nanotubes are arranged in a certain order, for example, equal-interval arrangement; slip gaps are formed between carbon nanotubes, with the gap size in a range of 400-700 nm, which exactly corresponds to the wavelength scope of visible light; the diameter of the carbon nanotube is in a range of 20 nm to 80 nm. 
     The action effect of the display screen film provided by the embodiment of the disclosure is as shown in  FIG. 2 , specifically as follows: when the emitted light  21  from the display screen  20  reaches the lower surface of the orientated carbon nanotube layer through the quartz glass layer  22 , small gaps between vertically grown carbon nanotubes  23  included in the orientated carbon nanotube layer, like many traps, make the light refracted for many times and then output from the upper surface of the orientated carbon nanotube layer as almost vertical light; in this way, this film has a guiding function for the light emitted from the screen. The film is formed by a quartz glass layer  22  which has carbon nanotube  23  vertically grown thereon. This film is attached on the surface of a display screen  20  to serve as a display screen film. 
     The comparison diagram showing situations with or without the display screen film provided by the embodiment of the disclosure applied to a display screen is as shown in  FIG. 3 . As shown in  FIG. 3( a ) , without the film, the surface of the display screen emits an omni-directional 180-degree visual angle of light; as shown in  FIG. 3( b ) , with the film, after the light emitted from the surface of the display screen passes through the film shown in  FIG. 1 , since the film has a guiding function for the light emitted from the surface of the display screen, the light emitted from the upper surface of the film is changed to be in a smaller scope almost perpendicular to the display screen. In this way, in the condition that the whole display screen brightness is reduced to ⅓ of the original brightness, it is ensured that energy saving can be achieved without the reduction of a user&#39;s visual perception within the smaller scope, thereby improving the endurance capability of mobile terminal. 
     In addition, growing an orientated carbon nanotube layer on a quartz glass layer can be implemented by using the electrical, magnetic and other properties of the carbon nanotube itself, for example, high-molecular induced orientation method, electrical-field induced orientation method, magnetic-field induced orientation method and so on. 
     The above are the preferred embodiments of the disclosure and are not intended to limit the scope of protection of the disclosure.