Abstract:
A light-emitting method is provided. The light-emitting method is applied in a light-emitting device. The light-emitting device includes an emitting member to emit light. The light-emitting method includes detecting an air pressure of the light-emitting device and controlling the emitting member to emit light with color and luminance value according to the detected air pressure. A related light-emitting device is also provided.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to light-emitting devices and light-emitting methods and, particularly, to a light-emitting device capable of emitting light with various colors and luminance and a method for controlling the light-emitting device to emit light. 
     2. Description of Related Art 
     LED lamps are becoming a more popular choice than conventional bulb lamps for use in many conventional illumination applications, such as table lamps. However, conventional LED lamps only can emit light with a single color, which may not satisfy users&#39; different demands. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of a light-emitting device and a light-emitting method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric view of a light-emitting device in accordance with an exemplary embodiment. 
         FIG. 2  is an exploded, perspective view of the light-emitting device of  FIG. 1 . 
         FIG. 3  is a block diagram of a circuit board of the light-emitting device of  FIG. 1 . 
         FIG. 4  is a flowchart of a light-emitting method in accordance with a first embodiment. 
         FIG. 5  is a flowchart of a light-emitting method in accordance with a second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-2 , a light-emitting device  100  in accordance with an exemplary embodiment is shown. The device  100  includes a head  10 , a support  20 , and a base  30 . Two opposite ends of the support  20  are respectively connected to the head  10  and the base  30 . 
     The head  10  includes a lampshade  11  and an emitting member  12 . The lampshade  11  defines a receiving space  110  with an opening (not labeled). The emitting member  12  is received in the receiving space  110 . In the embodiment, the lampshade  11  is filled with gas and the volume of the lampshade  11  correspondingly changes when the air pressure of the lampshade  11  changes. The volume of the lampshade  11  increases while the air pressure of the lampshade  11  increases, and the volume decreases while the air pressure of the lampshade  11  decreases. The lampshade  11  is made of transparent material. The lampshade  11  may be balloon-shaped. The emitting member  12  emits light with various colors, such as, green light, red light, blue light, or light with mixed colors. 
     The support  20  includes a first rod  21 , a second rod  22 , an inflatable bag  23 , a first valve  24 , a second valve  25 , and a circuit board  26 . 
     The first rod  21  and the second rod  22  respectively define through holes  210  and  220  along axes of the first rod  21  and the second rod  22 . The emitting member  12  is attached to a top end of the first rod  21 . The top end of the first rod  21  is attached to the lampshade  11 , and the through hole  210  and the receiving space  110  cooperatively form a chamber  211 . The first valve  24  is fixedly received in the through hole  210  to allow gas to flow through. Opposite ends of the second rod  22  are respectively attached to the inflatable bag  23  and the base  30 . The second valve  25  is fixedly received in the through hole  220  to allow gas to flow through. The first valve  24  and the second valve  25  are both check valves and allow gas to flow through the first valve  24  and the second valve  25  in a direction towards the lampshade  11 . 
     The inflatable bag  23  is made of elastic material. The inflatable bag  23  defines a through hole  230  along an axis thereof. Opposite ends of the inflatable bag  23  are respectively attached to the first rod  21  and the second rod  22 . The inflatable bag  23  inflates the chamber  211  to make the size of the lampshade  11  increase in response to extrusion of the inflatable bag  23  through the through hole  230 . 
     The circuit board  26  is secured in the through hole  210  and electrically connected to the emitting member  12 . The circuit board  26  detects the air pressure of the chamber  211  and control the emitting member  12  to emit light according to the detected air pressure. 
     The base  30  includes a positioning member  31  and a stand  32 . The positioning member  31  defines a receiving space  310  with an opening, and is attached to the bottom end of the second rod  22 . The receiving space  310  communicates with the through hole  220 . The positioning member  31  defines a number of holes  311 , from which the gas can go into the positioning member  31  flowing to the second rod  22  and exhaust from the positioning member  31 . In one embodiment, the positioning member  31  is spheroidal. At least a portion of the positioning member  31  is made of magnetic or magnetizable material. 
     The stand  32  defines a recessed portion  320  to receive the positioning member  31 . When the positioning member  31  is received in the recessed portion  320 , the holes  311  of the positioning member  31  are exterior to the recessed portion  320 . At least a portion of the stand  32  is made of magnetic or metal material. In one embodiment, when at least a portion of the positioning member  31  is made of magnetic material, at least a portion of the stand  32  is made of magnetic or magnetizable material. If at least a portion of the positioning member  31  is made of magnetizable material, at least a portion of the stand  32  is made of magnetic material. Therefore, the positioning member  31  and the stand  32  are secured together by the attraction between the positioning member  31  and the stand  32 , and the positioning member  31  can be rotated and held in a desired position to adjust orientation of the light-emitting device  100 . 
     Referring to  FIG. 3 , a block diagram of the circuit board  26  is shown. The circuit board  26  includes a sensor  261 , a storage unit  262 , and a processor  263 . 
     The sensor  261  detects the air pressure of the chamber  211 . In one embodiment, the air pressure of the chamber  211  changes while the inflatable bag  23  is extruded. 
     The storage unit  262  stores a table recording relationship among different air pressure ranges, colors, and luminance values. As shown below, the table includes a first column recording different air pressure ranges, a second column recording different colors, and a third column recording different luminance values. Each air pressure range corresponds to one color and one luminance value. Each luminance value is a percentage of a greatest luminance of the light-emitting device  100 . 
     
       
         
               
               
               
             
           
               
                 TABLE 
               
               
                   
               
               
                 Air pressure range 
                 Color 
                 Luminance 
               
               
                   
               
             
             
               
                 100-110 KPa 
                 Green 
                 30% 
               
               
                 111-120 KPa 
                 Blue 
                 60% 
               
               
                 121-130 KPa 
                 Yellow 
                 90% 
               
               
                 131-140 KPa 
                 Red 
                 100%  
               
               
                 . . . 
                 . . . 
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     The processor  263  includes a determining module  264  and an executing module  265 . 
     In one embodiment, the determining module  264  is configured to determine whether the air pressure of the chamber  211  detected by the sensor  261 , falls within one air pressure range recorded in the table, and determines the color and the luminance values corresponding to the detected air pressure range in the table if the detected air pressure falls within the air pressure range. 
     The executing module  265  is configured to control the emitting member  12  to emit light with the color and the luminance value determined by the determining module  264  if the detected air pressure falls within one air pressure range. Then it turns off the light emitting device  100  if the detected air pressure does not fall within any air pressure range. 
     In an alternative embodiment, the determining module  264  is configured to determine whether the air pressure of the chamber  211  is steady. The executing module  265  is configured to emit light with a single color and a fixed luminance value if the air pressure of the chamber  211  is steady, and is configured to emit light with various colors and luminance values alternatively if the air pressure of the chamber  211  changes. 
     It should be noted that in above embodiments, the executing module  265  is further configured to shut down the first valve  24  to prevent the air from going through when the air pressure of the chamber  211  reaches a predetermined value. 
     Referring to  FIG. 4 , a first embodiment of a method for controlling the light-emitting device  100  to emit light is shown. 
     In step S 401 , the sensor  261  detects the air pressure of the chamber  211 . 
     In step S 402 , the determining module  264  determines whether the air pressure of the chamber  211  falls within one air pressure range in the table. If not, the procedure goes to step S 403 . If yes, the procedure goes to step S 404 . 
     In step S 403 , the executing module  265  shuts down the light-emitting device  100 . 
     In step S 404 , the determining module  264  determines the color and luminance value corresponding to the air pressure range in the table. 
     In step S 405 , the executing module  265  controls the emitting member  12  to emit color and luminance value determined by the determining module  264 , and the procedure goes to S 401 . 
     Referring to  FIG. 5 , a second embodiment of a method for controlling the light-emitting device  100  to emit light is shown. 
     In step S 501 , the sensor  261  detects the air pressure of the chamber  211 . 
     In step S 502 , the determining module  264  determines whether the air pressure of the chamber  211  is steady. If yes, the procedure goes to step S 503 . If not, i.e., not kept within one air pressure, the procedure goes to step S 504 . 
     In step S 503 , the executing module  265  controls the emitting member  12  to emit a light with single color and a fixed luminance value, and the procedure goes to step S 501 . 
     In step S 504 , the executing module  265  controls the emitting member  12  to emit a light with various colors and luminance value alternatively, and the procedure goes to step S 501 . 
     Although the present disclosure has been specifically described on the basis of the exemplary embodiment thereof, the disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the embodiment without departing from the scope and spirit of the disclosure.