Abstract:
The present invention is directed to an illumination system adaptable to a cooling appliance. The illumination system includes a lighting module, a mode switch and a controller. Specifically, the lighting module includes at least one lighting device; the mode switch is used to determine a power mode for the lighting module; and the controller provides corresponding power to the lighting device according to the power mode. In one embodiment, the illumination system further includes a heating module having a heater for providing heat to the controller. In another embodiment, the lighting device is disposed near the controller.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The entire contents of Taiwan Patent Application No. 099110264, filed on Apr. 2, 2010, from which this application claims priority, are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention generally relates to an illumination system, and more particularly to an illumination system adaptable to a cooling appliance. 
         [0004]    2. Description of Related Art 
         [0005]    Due to various advantages of a light-emitting diode (LED) such as small volume, short response time, low power consumption, high reliability and high feasibility of mass production, the LED is replacing conventional lighting device such as light bulb or fluorescent lamp. The LED may be widely applied in various lighting applications such as indoor lighting, outdoor lighting or light indication. Moreover, the LED may be used as a lighting device in an extreme condition such as a cooling appliance of commercial or industrial use. 
         [0006]    However, in such extreme condition, the LED may be over-heated or even damaged owing to improper use. Further, an illumination may not recover from an abnormal condition (e.g., power blackout) due to overly low temperature of a control circuit. 
         [0007]    Accordingly, a need has arisen to propose a novel illumination system adaptable to a cooling appliance to protect the LED and ensure normal working of the illumination system. 
       SUMMARY OF THE INVENTION 
       [0008]    An object of the embodiment of the present invention is to provide an illumination system adaptable to a cooling appliance that is capable of switching power mode and protecting a lighting device in an abnormal condition to ensure normal working of a controller. 
         [0009]    According to one embodiment, an illumination system adaptable to a cooling appliance includes a lighting module, a mode switch and a controller. Specifically, the lighting module includes at least one lighting device. The mode switch determines a power mode for the lighting module. The controller provides corresponding power to the lighting device according to the power mode. In one embodiment, the illumination system further includes a heating module having a heater for providing heat to the controller. In another embodiment, the lighting device is disposed near the controller to prevent the temperature of the controller from being too low. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  shows a block diagram of an illumination system adaptable to a cooling appliance according to one embodiment of the present invention; 
           [0011]      FIG. 2  shows exemplary power mode switching for the LED; and 
           [0012]      FIG. 3  shows a block diagram of an illumination system adaptable to a cooling appliance according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]      FIG. 1  shows a block diagram of an illumination system  1  adaptable to a cooling appliance according to one embodiment of the present invention. The illumination system of the present invention may be adapted to any cooling appliance of industrial, commercial or household use. 
         [0014]    The illumination system  1  primarily includes a mode switch  10 , a controller  12 , a lighting module  14  and a heating module  16 . In the embodiment, the mode switch  10  is a normally-closed (NC) switch, which forms a closed circuit in a normal condition. The circuit becomes open when the mode switch  10  is pressed, and the circuit becomes closed again when the mode switch  10  is released. As shown in  FIG. 1 , one terminal of the mode switch  10  receives power from a power supply  3 , and another terminal of the mode switch  10  is coupled to transfer the power to the controller  12 . 
         [0015]    In the embodiment, the controller  12  receives the power transferred from the mode switch  10 , and a driving circuit  120  is utilized to generate corresponding power PLED to drive a lighting device such as a light-emitting device (LED)  140  of the lighting module  14 . The preferred embodiment uses at least one LED  140  as the lighting device to achieve the purpose of energy saving. It is appreciated that other types of lighting device such an organic light-emitting device (OLED) may be used in other embodiments. The LED  140  may be driven by current, voltage or by other ways, and the provided power PLED may be current/voltage of direct-current (DC), alternating-current (AC), pulse-width modulation (PWM) or other formats. Further, the controller  12  determines a power mode according to the pressing of the mode switch  10  in order to correspondingly provide proper power to the LED  140 . The controller  12  of the present embodiment may be implemented by analog and/or digital circuit or firmware technique. 
         [0016]      FIG. 2  shows exemplary power mode switching for the LED  140 . As the controller  12  detects the pressing and releasing of the mode switch  10 , a low-power mode (e.g., 0 or 1 watt) is switched to a medium-power mode (e.g., 10 watts). As the controller  12  detects once again the pressing and releasing of the mode switch  10 , the medium-power mode is switched to a high-power mode (e.g., 20 watts). As the controller  12  detects once more the pressing and releasing of the mode switch  10 , the high-power mode is switched back to the low-power mode. The power modes may therefore be recursively switched in order. It is appreciated that the power mode switching shown in  FIG. 2  is merely instantiated. The number of the power modes and their sequence may be arranged according to a specific application, and are not limited by that depicted in  FIG. 2 . 
         [0017]    In the embodiment, the lighting module  14  further comprises a first thermal sensor (or temperature sensor)  142 , which is disposed near the LED  140  to detect the temperature of the LED  140 . The term “near” in this specification may refer to two objects that contact one another, or may refer to two objects that are at a predetermined distance from one another. A first sense signal S 1  generated by the first thermal sensor  142  is fed to the controller  12 . Accordingly, when the temperature of the LED  140  is too high (e.g., higher than a predetermined first threshold high temperature) in an abnormal condition caused, for example, by power blackout or improper use by a user, a comparator  122  of the controller  12  may detect the abnormality by comparing the first sense signal S 1  with the first threshold high temperature. Based on the detection, abnormality handling may be performed, for example, by decreasing the power PLED provided to the LED  140 , in order to prevent damage or shortened lifetime in the LED  140 . Although single first threshold high temperature is used in the embodiment, more than one threshold high temperature may be used in other embodiments to adjust different power PLED respectively. The term “first” threshold high temperature in this specification refers a threshold high temperature associated with the first sense signal  51 . 
         [0018]    In the embodiment, the heating module  16  is disposed near the controller  12 . The heating module  16  includes a heater  160  and a second thermal sensor  162 , and a second sense signal S 2  generated by the second thermal sensor  162  is fed to the controller  12 . Accordingly, when the temperature of the controller  12  is too low (e.g., lower than a predetermined second threshold low temperature such as −20 degree Celsius) in an abnormal condition, the comparator  122  of the controller  12  may detect the abnormality by comparing the second sense signal S 2  with the second threshold low temperature. At that time, the controller  12  may utilize the driving circuit  120  to provide a proper power P H  to the heater  160  such that the generated heat may maintain the controller  12  at a proper temperature to ensure normal working of the controller  12 . 
         [0019]    In another embodiment, the comparator  122  of the controller further compares the second sense signal S 2  with a predetermined second threshold high temperature (which may be not the same as the first threshold high temperature associated with the first sense signal S 1 ). When the second sense signal S 2  is greater than the second threshold high temperature, the power P H  provided to the heater  160  is decreased in order to prevent the temperature of the heater  160  from being too high. Although single second threshold high temperature and single second threshold low temperature are used in the embodiment, multiple threshold temperatures between the second threshold high temperature and the second threshold low temperature may be used in other embodiments to adjust different power P H  respectively. The heater  160  may be driven by current, voltage or by other ways, and the provided power P H  may be current/voltage of DC, AC, PWM or other formats. The term “second” threshold high/low temperature in this specification refers a threshold high/low temperature associated with the second sense signal S 2 . 
         [0020]    The embodiment may further include an uninterruptible power supply (UPS)  18 . When power interruption (e.g., power blackout) of the power supply  3  is detected via a conducting wire  180 , the UPS  18  may provide power, via the mode switch  10 , to the controller  12 , the lighting module  14  and/or the heating module  16 . 
         [0021]      FIG. 3  shows a block diagram of an illumination system  2  adaptable to a cooling appliance according to another embodiment of the present invention. The blocks being the same as those in  FIG. 1  use same reference numerals, and their associated functions or compositions are omitted for brevity. The present embodiment ( FIG. 3 ) is similar to the previous embodiment ( FIG. 1 ), with the main exception that the lighting module  14  of the present embodiment is disposed near the controller  12  to provide the LED generated heat to the controller  12  in order to prevent the temperature of the controller  12  from being too low. Accordingly, the present embodiment may omit the heating module  16 , and therefore may substantially save cost and energy. The present embodiment uses at least one LED  140  as the lighting device to achieve the purpose of energy saving. It is appreciated that other types of lighting device such an organic light-emitting device (OLED) may be used in other embodiments. 
         [0022]    The present embodiment may adopt the power mode switching depicted in  FIG. 2 , but the low-power mode need provide power greater than 0 watt to the LED  140  to ensure that the temperature of the controller  12  is not too low. In the embodiment, the first thermal sensor  142  is capable of detecting not only the first threshold high temperature to prevent the temperature of the LED  140  from being too high, but also the first threshold low temperature to prevent the temperature of the controller  12  from being too low. When the comparator  122  detects that the first sense signal S 1  is greater than the first threshold high temperature, the power PLED provided to the LED  140  is decreased to prevent the temperature of the LED  140  from being too high. When the comparator  122  detects that the first sense signal S 1  is lesser than the first threshold low temperature, the power PLED provided to the LED  140  is increased to prevent the temperature of the controller from being too low. The term “first” threshold high/low temperature in this specification refers a threshold high/low temperature associated with the first sense signal S 1 . 
         [0023]    Although specific embodiments have been illustrated and described, it will be appreciated by those skilled in the art that various modifications may be made without departing from the scope of the present invention, which is intended to be limited solely by the appended claims.