Multi-lens zoom system and method for flashlights

Abstract

An efficient system and method for zooming the light from a flashlight is disclosed. Multiple refractive lenses are translated in unison to allow zooming of the light while reducing the size and weight of the required lenses. In another aspect, a meniscus lens is used to reduce the amount of light lost from a light-emitting diode (LED). One method includes providing a light source in a housing and translating a lens arrangement substantially along a light path of a light beam generated by the light source. The lens arrangement includes at least two refractive lenses separated by a gap, a size of the gap being maintained during translation of the lens arrangement.

1 . A method of directing light in a flashlight, comprising: 
 providing a light source within a housing, the light source being adapted to generate a light beam along a light path; and    positioning a lens arrangement substantially along the light path, the lens arrangement including a lens closest to the light source,    wherein a surface of the lens closest to the light source facing the light source is a meniscus surface having a concave configuration, and    wherein the housing includes a water-tight cavity formed therein.    
   
   
       2 . The method of  claim 1 , wherein the housing includes an inner housing and an outer housing adapted to rotate relative to the inner housing to cause at least one lens of the lens arrangement to translate along the light path.  
   
   
       3 . The method of  claim 2 , further comprising: 
 positioning a seal between the inner housing and the outer housing to form the water-tight cavity within the housing.    
   
   
       4 . The method of  claim 1 , wherein the lens arrangement includes at least two lenses each having a refractive index between 1.2 and 1.8.  
   
   
       5 . The method of  claim 4 , wherein the refractive index is approximately 1.5.  
   
   
       6 . The method of  claim 1 , wherein the light source includes a light emitting diode (LED).  
   
   
       7 . A flashlight light-direction arrangement, comprising: 
 a light source positioned within a housing; and    a lens arrangement positioned substantially along a light path of a light beam generated by the light source, the lens arrangement including a lens closest to the light source;    wherein a surface of the lens closest to the light source facing the light source is a meniscus surface having a concave configuration, and    wherein the housing includes a water-tight cavity formed therein.    
   
   
       8 . The arrangement of  claim 7 , wherein the housing includes an inner housing and an outer housing adapted to rotate relative to the inner housing to cause at least one lens of the lens arrangement to translate along the light path.  
   
   
       9 . The arrangement of  claim 8 , further comprising: 
 a seal positioned between the inner housing and the outer housing to form the water-tight cavity within the housing.    
   
   
       10 . The arrangement of  claim 7 , wherein the lens arrangement includes at least two lenses each having a refractive index between 1.2 and 1.8.  
   
   
       11 . The arrangement of  claim 10 , wherein the refractive index is approximately 1.5.  
   
   
       12 . The arrangement of  claim 7 , wherein the light source includes a light emitting diode (LED).  
   
   
       13 . A system of directing light for a flashlight, comprising: 
 means for generating a light beam along a light path, the means for generating a light beam being positioned in a housing; and    a lens arrangement positioned substantially along a light path of a light beam generated by the means for generating a light beam, the lens arrangement including a lens closes to the means for generating a light beam;    wherein a surface of the lens closest to the means for generating a light beam facing the means for generating a light beam is a meniscus surface having a concave configuration, and    wherein the housing includes a water-tight cavity formed therein.    
   
   
       14 . The system of  claim 11 , wherein the housing includes an inner housing and an outer housing adapted to rotate relative to the inner housing to cause at least one lens of the lens arrangement to translate along the light path.  
   
   
       15 . The system of  claim 12 , further comprising: 
 means for sealing positioned between the inner housing and the outer housing to form the water-tight cavity within the housing.    
   
   
       16 . The system of  claim 11 , wherein the lens arrangement includes at least two lenses each having a refractive index between 1.2 and 1.8.  
   
   
       17 . The system of  claim 14 , wherein the refractive index is approximately 1.5.  
   
   
       18 . The system of  claim 13 , wherein the means for generating a light beam includes a light emitting diode (LED).  
   
   
       19 . A flashlight, comprising: 
 an illumination portion having a light source positioned within a housing; and    a lens arrangement positioned substantially along a light path of a light beam generated by the light source, the lens arrangement including a lens closest to the light source;    wherein the surface of the lens closest to the light source facing the light source is a meniscus surface having a concave configuration.    
   
   
       20 . The flashlight of  claim 19 , wherein the housing includes a water-tight cavity formed therein.  
   
   
       21 . The flashlight of  claim 19 , wherein the housing includes an inner housing and an outer housing adapted to rotate relative to the inner housing to cause at least one lens of the lens arrangement to translate along the light path.  
   
   
       22 . The flashlight of  claim 21 , further comprising: 
 a seal positioned between the inner housing and the outer housing to form a water-tight cavity within the housing.    
   
   
       23 . The flashlight of  claim 19 , wherein the lens arrangement includes at least two lenses each having a refractive index between 1.2 and 1.8.  
   
   
       24 . The flashlight of  claim 23 , wherein the refractive index is approximately 1.5.  
   
   
       25 . The flashlight of  claim 19 , wherein the light source includes a light emitting diode (LED).  
   
   
       26 . The flashlight of  claim 19 , wherein the lens closest to the light source is positioned to maintain a gap between the lens and the light source.  
   
   
       27 . The flashlight of  claim 19 , wherein the lens closest to the light source forms a cap substantially surrounding the LED light source.