Abstract:
An illumination system includes at least one illumination module and a mechanism. The illumination module includes a light source generating a light beam, a first reflector, in which the light source is positioned, including a first reflective surface to reflect the light beam to form a first beam, and a second reflector including a second reflective surface reflecting the light beam and the first beam to form a second beam and a third beam, wherein the second and third beams combine to generate a projection pattern. The mechanism adjusts the position of the second reflector relative to the light source to change the projection pattern.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority of Taiwan Patent Application No. 97146224, filed on Nov. 28, 2008, the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an illumination system, and in particular relates to an illumination system capable of changing a projection pattern by adjusting the positions of a reflector and a light source 
     2. Description of the Related Art 
     For a conventional optical design, a secondary lens and a reflector are used to generate a desired projection pattern. The secondary lens cannot change a projection pattern without affecting the emitting efficiency. Additionally, the reflector cannot concentrate an emitting angle of the light beam to the range of 10 to 45 degrees. 
     U.S. Pat. No. 4,037,036 discloses an optical design with the function of filtering UV/IR light reflected by a reflector. 
     U.S. Pat. No. 5,951,139 discloses a conventional operation lamp comprising a light source, a reflector and mirrors. The light from the light source is reflected by the reflector. The reflected light is reflected by the mirrors to generate a projection pattern. The mirrors are disposed around a circle with respect to the center of the operation lamp. 
     US patent publication No. 2006/0072313 discloses an optical design for light emitting diodes comprising a light source and a reflector. The reflector can be a lens or a hollow reflector. 
     BRIEF SUMMARY OF INVENTION 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     An embodiment of the illumination system of the invention comprises at least one illumination module and a mechanism. The illumination module comprises a light source generating a light beam, a first reflector in which the light source is positioned comprising a first reflective surface to reflect the light beam to form a first beam, and a second reflector comprising a second reflective surface reflecting the light beam and the first beam to form a second beam and a third beam, wherein the second and third beams combine to generate a projection pattern. The mechanism adjusts the position of the second reflector relative to the light source to change the projection pattern. 
     An embodiment of an operating lamp of the invention comprises a plurality of illumination modules and a mechanism. Each illumination module comprises a light source generating a light beam, a first reflector in which the light source is positioned comprising a first reflective surface to reflect the light beam to form a first beam, and a second reflector comprising a second reflective surface reflecting the light beam and the first beam to form a second beam and a third beam, wherein the second and third beams combine to generate a projection pattern. The mechanism adjusts the position of the second reflector relative to the light source to change the projection pattern. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an embodiment of the illumination system of the invention; 
         FIG. 2  is a side view of the illumination system of the invention; 
         FIG. 3  is a schematic view of the illumination system of the invention; 
         FIG. 4  is a side view of another embodiment of the illumination system of the invention; 
         FIG. 5  is a side view of another embodiment of the illumination system of the invention; and 
         FIG. 6  depicts the application of the illumination system of the invention. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     An embodiment of the illumination system of the invention is shown in  FIGS. 1 and 2 . Referring to  FIG. 1 , the illumination system  100  comprises a plurality of illumination modules  60  and a mechanism  30 . Referring to  FIGS. 2 and 3 , each illumination module  60  comprises a first reflector  10 , a second reflector  20  and a light source  90 . 
     The light source  90  is disposed in the first reflector  10 , as shown in  FIG. 3 . The first reflector  10  comprises a first reflective surface  12 . The second reflector  20  comprises a second reflective surface  22 . There are two types of light beams from the light source  90 . A first beam A is produced by a light beam reaching the first reflector  10  and being reflected by the first reflective surface  12  and a second beam B is produced by the first beam A being reflected by the second reflective surface  22  of the second reflector  20 . The second type of light beam, a third beam C, is produced by the light beam reaching the second reflector  20  and being reflected by the second reflective surface  22 . The second beam B and the third beam C form the desired projection pattern. 
     The first reflective surface  12  can be a curved surface, and in particular can be a parabolic surface or an elliptic surface, and the light source  90  can be disposed on the focus portion of the parabolic surface. 
     Similarly, the second reflective surface  22  can be a curved surface, and in particular can be a parabolic surface or an elliptic surface, and the light source  90  can be disposed on the focus portion of the parabolic surface. 
     The second reflectors  20  can be formed integrally or individually and are not limited to the structure and size in  FIG. 1 . 
     Referring to  FIG. 2  again, the mechanism  30  moves the second reflector  20  to approach or move away from the light source  90 , whereby the projection pattern is changed. The structure of the mechanism  30  is described as follows. 
     The mechanism  30  comprises a central shaft L, an extending portion L 2  extending from the central shaft L, an outer tube  32 , an inner tube  34  and a push rod  36 . The light source  90  and the first reflector  10  are disposed on the extending portion L 2 . The outer tube  32  is disposed around the inner tube  34  and capable of moving thereon along the central shaft L. The push rod  36  is connected to the inner tube  34  capable of rotating around the central shaft L. One or some posts  342  are disposed on the periphery of the inner tube  34 , and one or a few elongated grooves  322  are formed on the periphery of the outer tube  32 . Each groove  322  has two ends  322   a  and  322   b  with different heights. The post  342  engages the groove  322  and moves between the ends  322   a  and  322   b . When the push rod  36  is pushed, the inner tube  34  rotates around the central shaft L, and the post  342  also rotates and has relative motion with the groove  322 . The lateral walls  5  constrain the outer tube  32  to move along the central shaft L. Since the second reflector  20  is connected to the outer tube  32 , when the outer tube  32  moves, the second reflector  20  moves, whereby the second reflector  20  approaches or moves away from the first reflector  10  and the light source  90  to change the projection pattern. The grooves  322  can also be spiral, and the push rod  36  can be integrally formed with the inner tube  34 . 
     To ensure that the central shaft L rotates without linear movement and limit the rotation range of the push rod  36 , two or more posts  344  are disposed on the periphery of the central shaft L. A groove  324  is formed on the inner tube  34 . The post  344  engages the groove  324  and can move therein. When the push rod  36  rotates to abut the end of the groove  324 , the push rod  36  stops, whereby the inner tube  34  stop rotating. 
     Although the distance between the second reflector  20  and the light source  90  is changed by moving the second reflector  20  in the described embodiment, the distance can also be changed by moving the light source  90 . 
       FIG. 4  depicts another embodiment of the illumination system of the invention. Referring to  FIG. 4 , the second reflector  20  is fixed to a wall  7 . The light source  90  and the first reflector  10  are fixed to a sub-base L 3  which is joined to the outer tube  32 . When the outer tube  32  moves, the light source  90  moves up and down to approach or move away from the second reflector  20  to change the projection pattern. 
       FIG. 5  depicts another embodiment of the illumination system of the invention. Referring to  FIG. 5 , compared with the embodiment of  FIG. 4 , the outer tube  32  is eliminated. A groove  324 ′ vertically extends on the inner tube  34 . A post  344  is disposed on the periphery of the central shaft L′. The inner tube  34  is constrained by the post  344  engaging the groove  324 ′ to move vertically. A sub-base L 3  is connected to the inner tube  34 . In the embodiment, as the push rod  36  is joined to the inner tube  34 , the inner tube  34  is moved by pushing the push rod  36 . Because the sub-base L 3  is joined to the inner tube  34 , the sub-base L 3  is moved by the inner tube  34 , whereby the light source  90  and the first reflector  10  on the sub-base L 3  moves relative to the second reflector  20  to change the projection pattern. 
     The invention provides a new design for illumination system used in medicine. The new structure comprises two reflectors and one light source. One of the reflectors can move relative to the light source to change projection pattern so as to prevent shadow and blinding effect.  FIG. 6  depicts an illumination system comprising six illumination modules. For dental operations, more than four illumination modules are desired. For general operations, 20 or more illumination modules are used to generate a projection pattern without shadow and blinding effect. 
     In addition, to dissipate heat from the light source  90 , a heat dissipation device  346  is disposed on the central shaft (L or L′). The heat dissipation device  346  can be integrally formed with the central shaft (L or L′). 
     While the invention has been described by way of example and in terms of embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.