Temperature adjusting device for an LED light source

Abstract

A temperature adjusting device of the present invention is provided with: LED light sources 11 r, 11 g and 11 b; a temperature sensor 9 for detecting an ambient temperature of each of the LED light sources 11 r, 11 g and 11 b; a cooling fan 20 for cooling the LED light sources 11 r, 11 g and 11 b; a driving circuit 22 for driving the cooling fan 20; and a control unit 4 which on/off controls a voltage to be applied to the cooling fan 20 so as to set the ambient temperature within a predetermined range based upon results of detection by a temperature sensor 9, and in this arrangement, upon on/off controlling the applied voltage, the control unit 4 is allowed to gradually raise/lower the applied voltage.

What is claimed is:  
     
         1 . A temperature adjusting device for an LED light source comprising: 
 an LED light source;    a temperature sensor for detecting an ambient temperature of the LED light source;    a cooling fan for cooling the LED light source;    a driving circuit for driving the cooling fan; and    a control unit which on/off controls a voltage to be applied to the cooling fan so as to set the ambient temperature within a predetermined range based upon results of detection by the temperature sensor, characterized in that, upon on/off controlling the applied voltage, the control unit ( 4 ) is allowed to gradually raise/lower the applied voltage.    
     
     
         2 . The temperature adjusting device for an LED light source according to  claim 1 , characterized in that the control unit ( 4 ) turns the applied voltage on when the ambient temperature exceeds an upper-side switching temperature (T 2 ) that is set at a temperature lower than the upper limit of a temperature permissible range, and also turns the applied voltage off when the ambient temperature is lower than a lower-side switching temperature (T 1 ) that is set at a temperature higher than the lower limit of the temperature permissible range.  
     
     
         3 . Th temperature adjusting device for an LED light source according to  claim 1 , characterized in that the LED light source ( 11 ) is used for a scanner-use light source for reading frame images of a photographic film.  
     
     
         4 . The temperature adjusting device for an LED light source according to  claim 3 , further comprising: 
 a line-shaped heater ( 12 ) that is installed in the LED light source ( 11 ), and formed in a line shape along the width direction of a photographic film (F) to be read so as to be aligned adjacent to the LED light source ( 11 ) in the line direction,    characterized in that the control unit ( 4 ) turns the heater ( 12 ) off in synchronism with the turning-on of the LED light source ( 11 ), and on/off controls the cooling fan ( 20 ) independent of the on/off operations of the heater ( 12 ).    
     
     
         5 . The temperature adjusting device for an LED light source according to  claim 1 , characterized in that the LED light source ( 11 ) is used for an exposure-use light source for exposing and printing an image onto a photosensitive material.  
     
     
         6 . The temperature adjusting device for an LED light source according to  claim 1 , characterized in that the control unit ( 4 ) gradually increases/decreases the applied voltage linearly.  
     
     
         7 . The temperature adjusting device for an LED light source according to  claim 1 , characterized in that the control unit ( 4 ) gradually increases/decreases the applied voltage in a curved manner.  
     
     
         8 . The temperature adjusting device for an LED light source according to  claim 1 , characterized in that the time period in which the applied voltage is gradually increased/decreased is set to one to two seconds.  
     
     
         9 . The temperature adjusting device for an LED light source according to  claim 1 , characterized by comprising: 
 a red LED light source ( 11   r ), a green LED light source ( 11   g ), a blue LED light source ( 11   b ) that constitute a LED light source ( 11 );    a red LED guiding portion ( 13   r ), a green LED guiding portion ( 13   g ) and a blue LED guiding portion ( 13   b ) that guide light rays applied from the respective light sources ( 11   r,    11   g,    11   b ); and    a joining portion ( 13   a ) that allows the respective guiding portions to join to one another.    
     
     
         10 . The temperature adjusting device for an LED light source according to  claim 1 , characterized in that the LED light source ( 11 ) is a white-color LED.