Abstract:
A heat-dissipating method of a light emitting diode illuminator includes the following steps. First, the light emitting diode illuminator is provided and includes a light emitting diode, a fan apparatus, a temperature sensor and a controller. The controller is electrically connected with the fan and the temperature sensor. Second, a predetermined working temperature of the light emitting diode is defined in the controller. Third, a working temperature of the light emitting diode is sensed using the temperature sensor, and a signal of the working temperature is transmitted to the controller. Fourth, the working temperature sensed by the temperature sensor is compared with the predetermined working temperature in the controller, and the fan is adjusted by the controller to work at a suitable speed.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to illuminators and, particularly, to a light emitting diode (LED) illuminator and a heat-dissipating method thereof. 
         [0003]    2. Description of related art 
         [0004]    With the continuing development of scientific technology, light emitting diodes (LEDs) have been widely used in the field of illumination due to its high brightness, long lifespan, wide color gamut and so on. LEDs generally emit visible light at specific wavelengths and generate a significant amount of heat. Generally, approximately 80-90% of the electric energy consumed by the LEDs is converted to heat, with the remainder of the electric energy converted to light. If the generated heat cannot be timely dissipated, the LEDs may overheat, and thus the performance and lifespan maybe significantly reduced. 
         [0005]    Therefore, heat-dissipating apparatuses are applied in the illuminators to timely dissipate heat generated by the LEDs. The heat-dissipating apparatus includes a fan to induce an airflow for the purpose of cooling the LEDs and a number of fins. However, during the working process of the heat-dissipating apparatus, dust and suspending particles may exist in the surroundings of the illuminators. These dust and suspending particles may negatively impact and affect the working efficiency and lifespan of the fin of the heat-dissipating apparatus, thereby shortening the lifespan of the illuminators. 
         [0006]    What is needed, therefore, is a LED illuminator and a heat-dissipating method thereof which can overcome the above-described problems. 
       SUMMARY OF THE INVENTION 
       [0007]    An exemplary embodiment of a heat-dissipating method of a light emitting diode illuminator includes the following steps. First, the light emitting diode illuminator is provided and includes a light emitting diode, a fan apparatus, a temperature sensor and a controller. The controller is electrically connected with the fan and the temperature sensor. The fan is controlled by the controller to work at various speeds. Second, a predetermined working temperature of the light emitting diode is defined in the controller. Third, a working temperature of the light emitting diode is sensed using the temperature sensor, and a signal of the working temperature is transmitted to the controller. Fourth, the working temperature sensed by the temperature sensor is compared with the predetermined working temperature in the controller, and the fan is controlled by the controller to work at a suitable speed according to the comparison result between the working temperature and the predetermined working temperature. 
         [0008]    Advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Many aspects of the present embodiment can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiment. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0010]      FIG. 1  is a schematic, isometric view of a light emitting diode illuminator according to an exemplary embodiment. 
           [0011]      FIG. 2  is a flowchart of a heat-dissipating method of the light emitting diode illuminator of  FIG. 1 . 
           [0012]      FIG. 3  is a logical view of a heat-dissipating process of the light emitting diode illuminator of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    An embodiment will now be described in detail below and with reference to the drawings. 
         [0014]    Referring to  FIG. 1 , a LED illuminator  100  according to an exemplary embodiment is illustrated. The LED illuminator  100  includes at least a LED  110 , a heat-dissipating apparatus  120 , a temperature sensor  130 , and a controller  140 . 
         [0015]    The heat-dissipating apparatus  120  includes a heat-dissipating base  121 , a heat sink  122  and a fan  123 . The heat-dissipating base  121  includes a first surface  121   a  and a second surface  121   b  on an opposite side of the first surface  121   a . The LED  110  is defined on the first surface  121   a  of the heat-dissipating base  121 . The heat sink  122  is thermally connected to the second surface  121   b  of the heat-dissipating base  121 . The fan  123  is coupled with the heat sink  122 , and cooperates with the heat sink  122  to dissipate heat generated from the LED  110 . 
         [0016]    The temperature sensor  130  can be thermally connected to the heat-dissipating base  121  or the heat sink  122  to detect their temperatures, thereby evaluating or measuring a working temperature of the LED  110 . In the present embodiment, the temperature sensor  130  is thermally connected to the heat-dissipating base  121  to detect a temperature of the heat-dissipating base  121 , thereby evaluating or measuring the working temperature of the LED  110 . 
         [0017]    The controller  140  is electrically connected to the fan  123  and the temperature sensor  130 , respectively. The controller  140  includes a predetermined temperature and various speeds. At the predetermined temperature, the LED  110  cannot overheat and works normally. The temperature sensor  130  senses the working temperature of the LED  110  and transmits signals of the working temperature to the controller  140 . The controller  140  compares the working temperature with the predetermined working temperature, and adjusts the speed of the fan  123  according to the comparison result of the working temperature and the predetermined working temperature. Therefore, the controller  140  has functions of activating the fan  123 , stopping the fan  123  and adjusting the fan  123  to work at a suitable speed. For example, the fan  123  can be controlled by the controller  140  to work at various speeds. In the present embodiment, the fan  123  has two speeds, that is, a first speed (V 1 ) and a second speed (V 2 ) faster than the first speed. According to the requirement of heat to be dissipated in the working process of the LED  110 , the fan  123  can be controlled by the controller  140  to work in any of the first and second speeds. 
         [0018]    Referring to  FIG. 2 , an exemplary embodiment of a heat-dissipating method of the LED illuminator  100  includes: step  210 , defining a predetermined working temperature of the LEDs  110  in the controller; step  220 , sensing a working temperature of the LEDs  110  using the temperature sensor  130  and transmitting a signal of the working temperature to the controller  140 ; step  230 , comparing the working temperature sensed by the temperature sensor  130  with the predetermined working temperature and adjusting the fan  123  to work at a suitable speed using the controller  140  according to the comparison result of the working temperature and the predetermined working temperature. 
         [0019]    An detailed heat-dissipating process of the LED illuminator  100  is described below and with reference to  FIG. 3 . 
         [0020]    In a general step  210 , a predetermined working temperature (or a temperature range) of the LED  110  is defined in the controller  140  according to a working status of the LED illuminator  100 . In the present embodiment, the LEDs  110  are blue LEDs. About 40% of the electric energy of the LED  110  is converted to light, that is, about 60% electric energy is converted into heat energy. Thus, when the LEDs  110  work nonstop for a long period of time, the temperature of the environment surrounding the LEDs  110  (i.e., the working temperature) rises. The LEDs  110  normally works at a temperature below 120 degrees Celsius. In the present embodiment, the predetermined working temperature is set to be 70 degrees Celsius. However, the working temperature of the LEDs  110  is difficult to be measured directly, so the predetermined working temperature and the working temperature below are acquired by measuring the temperature of the heat-dissipating base  121 . That is, the predetermined working temperature and the working temperature below of the heat-dissipating base  121  are employed as the predetermined working temperature and the working temperature of the LEDs  110 . 
         [0021]    In a general step  220 , the temperature sensor  130  senses the working temperature of the LED  110 , and transmits a signal of the working temperature to the controller  140 . Specifically, during the working process of the LED illuminator  100 , the temperature sensor  130  continues to periodically sense the working temperature of the heat-dissipating base  121 , and transmits the signal of the working temperature to the controller  140 . 
         [0022]    In a general step  230 , the working temperature sensed by the temperature sensor  130  is compared with the predetermined working temperature using the controller  140 , and the fan  123  is adjusted by the controller  140  to work at a suitable speed according to the comparison result of the working temperature and the predetermined working temperature. At the beginning of the working of the LED illuminator  100 , the LEDs  110  generate a small amount of heat and the working temperature (T) of the LEDs  110  has not reach the predetermined working temperature value, i.e., 70 degrees Celsius. Under this condition, the fan  123  is in an “off” state. 
         [0023]    When the working temperature value of the heat-dissipating base  121  sensed by the temperature sensor  130  is higher than 70 degrees Celsius, the fan  123  activates and the controller  140  adjusts the fan  123  to work at the first speed (V 1 ). After a first period of time (t 1 ), the working temperature of the heat-dissipating base  121  is sensed again by the temperature sensor  130 , if the working temperature of the heat-dissipating base  121  is lower than 70 degrees Celsius, the fan  123  is controlled by the controller  140  to be stopped working, i.e., the fan  123  is in the “off” state. However, if the working temperature of the heat-dissipating base  121  is still higher than 70 degrees Celsius, the controller  140  adjusts the fan  123  to work at the second speed (V 2 ). Because the second speed is faster than the first speed, the airflow of the fan  123  flows more quickly than the first speed. After a second period of time (t 2 ), the working temperature of the heat-dissipating base  121  is sensed again by the temperature sensor  120 , if the working temperature of the heat-dissipating base  121  is lower than 70 degrees Celsius, the fan  123  is controlled by the controller  140  to stop working or to work at the first speed. If the working temperature of the heat-dissipating base  121  is higher than 70 degrees Celsius, the fan  123  continuously works at the second speed until the working temperature is lower than 70 degrees Celsius. It is understood that three or more speeds can be defined in the controller  140  to adjust the fan  123  to works at three or more speeds, thereby accommodating the heat-dissipating requirement of the LEDs  110 . 
         [0024]    In the heat-dissipating method of the LED illuminator  100 , the working temperature of the LEDs  110  is sensed periodically by the temperature sensor  130 , and is compared with the predetermined working temperature of the LEDs  110  by the controller  1   40 . According to the comparison result, the fan  123  is adjusted by the controller  140  to work at a suitable speed, for example, stops working, works at the first speed, works at the second speed. That is, the working speed of the fan  123  can be adjusted according to the quantity of the heat to be dissipated of the LEDs  110 , thereby avoiding the fan  123  continuously working at a high speed. Therefore, the present heat-dissipating method prevents the LEDs  110  from overheating, simultaneously saves the energy of the fan  123  and extends the service lifetime of the fan  123 . Accordingly, the service lifetime of the illuminator is extended. 
         [0025]    It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.