Abstract:
A zoom spotlight has a reflector, a light source, a fixed lens, and a movable lens. The movable lens of the zoom spotlight can be moved and thereby adjusted in position relative to the fixed lens so that the zoom spotlight can output a broad beam, a collimated beam, or a beam ranging between the broad beam and the collimated beam, according to the user&#39;s needs.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a spotlight and more particularly to a zoom spotlight with a fixed lens and a movable lens. 
         [0003]    2. Description of Related Art 
         [0004]    The market demand for energy-saving products is increasing with the modernization of society and the rise of environmental awareness. Meanwhile, rapid development of the light-emitting diode (LED) and organic light-emitting diode (OLED) industry has lowered the costs of LEDs and OLEDs significantly, turning these lighting elements into the mainstream of energy-saving illumination. 
         [0005]    In particular, LEDs and OLEDs are widely used in spotlights, especially high-power LED spotlights, which are nowadays the principal products in spotlight applications. The conventional spotlights, which feature high power consumption and tend to generate heat easily, have given way to high-power LED spotlights in such fields as special lighting, search and rescue, stage and runway design, and automotive lighting. 
         [0006]    However, the market is still in want of a high-power LED spotlight which can directly output a broad beam, a collimated beam, or a beam ranging between the broad beam and the collimated beam, let alone a high-power LED spotlight capable of zooming. 
         [0007]    On the other hand, most of the conventional spotlights require a complicated manufacturing process in mass production, and the finished spotlights are simply incapable of outputting an approximately collimated beam, meaning stray light will be generated during operation and thus compromise efficiency of use. 
         [0008]    It is therefore highly desirable in the LED, OLED, and spotlight application-related industries to have a useful, low-cost yet high-quality, compact zoom spotlight which can be easily manufactured from simple optical and mechanical components without using expensive equipment, and which can output a broad and uniform beam in a broad beam mode and an approximately collimated beam without stray light in a collimated beam mode. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    The present invention provides a zoom spotlight which has a light source, a reflector, a fixed lens, and a movable lens. The movable lens of the zoom spotlight can be moved in order to be adjusted in position relative to the fixed lens so that the zoom spotlight can output a broad beam, a collimated beam, or a beam ranging between the broad beam and the collimated beam to meet the user&#39;s needs. 
         [0010]    More specifically, the present invention provides a zoom spotlight which includes a reflector, a light source, a fixed lens, and a movable lens. The reflector has a central axis, a light exit opening, and a bottom side opposite the light exit opening. The central axis is the line connecting the center point of the light exit opening and the center point of the bottom side. The light source is fixedly provided at the bottom side and is located on the central axis. The fixed lens is fixedly provided at the light exit opening and is located in the reflector, with the axis of the fixed lens coinciding with the central axis. In addition, the periphery of the fixed lens is fixedly provided with a first light-blocking sleeve which extends toward the light source. The movable lens, on the other hand, is movably provided between the light source and the fixed lens and is located on the central axis. The periphery of the movable lens is fixedly provided with a second light-blocking sleeve which extends toward the light source. 
         [0011]    Implementation of the present invention at least provides the following advantageous effects:
   1. Structural simplicity, ease of manufacture, and low costs.   2. The ability to output a broad beam, a collimated beam, or a beam ranging between the broad beam and the collimated beam.   
 
         [0014]    The features and advantages of the present invention are detailed hereinafter with reference to the preferred embodiments. The detailed description is intended to enable a person skilled in the art to gain insight into the technical contents disclosed herein and implement the present invention accordingly. In particular, a person skilled in the art can easily understand the objects and advantages of the present invention by referring to the disclosure of the specification, the claims, and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0015]    The invention as well as a preferred mode of use, further objectives and advantages thereof will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
           [0016]      FIG. 1  is a schematic sectional view of the zoom spotlight in an embodiment of the present invention; 
           [0017]      FIG. 2  schematically shows how light rays propagate from the light source of the zoom spotlight in an embodiment of the present invention; 
           [0018]      FIG. 3  schematically shows how light rays propagate from the light source of the zoom spotlight in  FIG. 2  when the movable lens is at a different position; 
           [0019]      FIG. 4  is a schematic sectional view of the zoom spotlight in another embodiment of the present invention, wherein the zoom spotlight includes a light-permeable plate; 
           [0020]      FIG. 5  is another schematic sectional view of the zoom spotlight in  FIG. 4 , with the movable lens at a different position; 
           [0021]      FIG. 6  is a schematic sectional view of the zoom spotlight in yet another embodiment of the present invention, wherein the zoom spotlight includes a heat dissipation mechanism; and 
           [0022]      FIG. 7  is a schematic sectional view of the zoom spotlight in still another embodiment of the present invention, wherein the zoom spotlight includes both a light-permeable plate and a heat dissipation mechanism. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Referring to  FIG. 1 , the zoom spotlight  100  in an embodiment of the present invention includes a reflector  10 , a light source  20 , a fixed lens  30 , and a movable lens  50 . 
         [0024]    As shown in  FIG. 1 , the reflector  10  has a central axis  11 , a light exit opening  12 , and a bottom side  13  opposite the light exit opening  12 . The central axis  11  is the line connecting the center point of the light exit opening  12  and the center point of the bottom side  13 . The shape or material of the reflector  10  is such that the inner surface of the reflector  10  can reflect incident light and project the reflected light out of the light exit opening  12  by method of approximate collimating beam or small divergence angle. 
         [0025]    With continued reference to  FIG. 1 , the light source  20  is fixedly provided at the bottom side  13 , located on the central axis  11 , and opposite the light exit opening  12 . The light source  20  can be at least one LED, at least one OLED, or a combination of at least one LED and at least one OLED. Depending on application requirements, the light emitted by the light source  20  can be of a single color (e.g., white, yellow, or any other color) or be a mixture of at least two color lights. 
         [0026]    Referring again to  FIG. 1 , the fixed lens  30  is fixedly provided at the light exit opening  12  and is located in the reflector  10 , with the axis of the fixed lens  30  in line with the central axis  11  of the reflector  10 . Also, the periphery of the fixed lens  30  is fixedly provided with a first light-blocking sleeve  40  extending toward the light source  20 . 
         [0027]    The position where the fixed lens  30  is fixedly provided at the light exit opening  12  is so chosen that one surface of the fixed lens  30  is flush with the light exit opening  12  while the opposite surface of the fixed lens  30  is situated inside the reflector  10 . 
         [0028]    The fixed lens  30  can be a positive lens, a negative lens, a Fresnel lens, a liquid lens, a liquid crystal (LC) lens or a spatial light modulator (SLM) with phase modulation. The first light-blocking sleeve  40  can be formed of a light-absorbing material or a material with a frosted surface so that light projected from the light source  20  to the first light-blocking sleeve  40  will not penetrate or be reflected by the first light-blocking sleeve  40 . Should such penetration or reflection take place, stray light traveling in arbitrary directions will occur. 
         [0029]    As is well known in the art, a positive lens refers to a lens which produces a focused (i.e., converging) beam on the side of the lens that is opposite the side where the source light (e.g., collimated or approximately parallel rays of light) enters the lens in a direction parallel to the optical axis of the lens. A negative lens, on the other hand, refers to a lens which produces a diverging beam on the side of the lens that is opposite the side where the source light (e.g., collimated or approximately parallel rays of light) enters the lens in a direction parallel to the optical axis of the lens, and which produces a focused virtual image on the side of the lens where the source light enters the lens. 
         [0030]    As shown in  FIG. 2  and  FIG. 3 , the length of the first light-blocking sleeve  40  is so designed that not a single ray of light emitted by the light source  20  can be projected out of the light exit opening  12  of the reflector  10  directly. 
         [0031]    Referring back to  FIG. 1 , the movable lens  50  is movably provided between the light source  20  and the fixed lens  30  and is located on the central axis  11 . In addition, the periphery of the movable lens  50  is fixedly provided with a second light-blocking sleeve  70  which extends toward the light source  20 . The diameter D 2  of the movable lens is less than the diameter D 1  of the fixed lens in order for the movable lens  50  fixedly provided with the second light-blocking sleeve  70  to be movable between the fixed lens  30  and the light source  20 . 
         [0032]    The movable lens  50  can be a positive lens, a negative lens, a Fresnel lens, a liquid lens, a liquid crystal (LC) lens, or a spatial light modulator (SLM) with phase modulation. The second light-blocking sleeve  70  can be formed of a light-absorbing material or a material with a frosted surface so that light projected from the light source  20  to the second light-blocking sleeve  70  will not penetrate or be reflected by the second light-blocking sleeve  70 . Should such penetration or reflection take place, there will be stray light traveling in arbitrary directions. 
         [0033]    As the position of the movable lens  50  relative to the fixed lens  30  varies, light projected to and passing through the movable lens  50  may fall on and penetrate the fixed lens  30  in whole or in part, as detailed below with reference to  FIG. 2  and  FIG. 3 . 
         [0034]    Referring to  FIG. 2 , light rays propagating from the light source  20  in direction A or in a direction which forms with the central axis  11  an included angle greater than the included angle between direction A and the central axis  11  are blocked by the bottom light-blocking sleeve  10   a  of the reflector  10  and are therefore prevented from being projected out of the light exit opening  12  of the reflector  10  (the line segments drawn in dashed lines and marked with X represent light ray sections which would have existed if not blocked). 
         [0035]    With continued reference to  FIG. 2 , light rays propagating from the light source  20  in direction B or in a direction which forms with the central axis  11  an included angle less than the included angle between direction A and the central axis  11  and greater than the included angle between direction C and the central axis  11  impinge on and are reflected by the reflector  10  and are consequently projected out of the light exit opening  12  by method of approximate collimating beam or small divergence angle. 
         [0036]    Referring again to  FIG. 2 , light rays propagating from the light source  20  in a direction which forms with the central axis  11  an included angle less than the included angle between direction C and the central axis  11  and greater than the included angle between direction D and the central axis  11  are blocked by the first light-blocking sleeve  40 , which, as mentioned above, can be formed of a light-absorbing material and therefore neither allows passage of nor reflects the light rays. In other words, the light rays will not result in stray light that travels in random directions. 
         [0037]    Light rays propagating from the light source  20  in direction D are blocked by the second light-blocking sleeve  70  and are therefore prevented from being projected out of the light exit opening  12  (the line segments in  FIG. 2  which are drawn in dashed lines and marked with X represent light ray sections which would have existed if not blocked). 
         [0038]    Referring to  FIG. 2  again, light rays propagating from the light source  20  in a direction which forms with the central axis  11  an included angle less than the included angle between direction D and the central axis  11  and greater than the included angle between direction E and the central axis  11  are blocked by the second light-blocking sleeve  70 , which, as previously mentioned, can be formed of a light-absorbing material and therefore neither allows passage of nor reflects the light rays. In other words, the light rays will not result in stray light that travels in random directions. 
         [0039]    With continued reference to  FIG. 2 , light rays propagating from the light source  20  in a direction which forms with the central axis  11  an included angle less than the included angle between direction E and the central axis  11  impinge on the movable lens  50  and are modulated by the movable lens  50  while passing therethrough. The modulated light rays then impinge on the fixed lens  30  and are modulated thereby into a collimated beam  60 , which is projected out of the light exit opening  12 . 
         [0040]    In summary, when the zoom spotlight  100  is in the configuration shown in  FIG. 2 , the relative positions of the movable lens  50  and the fixed lens  30  are such that a portion of the light projected from the light source  20  is reflected by the reflector  10  and hence projected out of the light exit opening  12 . Meanwhile, the remaining portion of the light projected from the light source  20  is blocked by the bottom light-blocking sleeve  10   a  of the reflector  10 , the first light-blocking sleeve  40 , or the second light-blocking sleeve  70 , modulated by the movable lens  50 , projected to and modulated by the fixed lens  30 , and then cast out of the light exit opening  12  as the collimated beam  60 . 
         [0041]    Referring to  FIG. 3 , once the movable lens  50  and the second light-blocking sleeve  70  are moved along the central axis  11  to a position adjacent to the light source  20 , most of the light emitted by the light source  20  impinges on the second light-blocking sleeve  70  and the movable lens  50 . 
         [0042]    It is worth mentioning that the component(s) or method used in the embodiments of the present invention to move the movable lens  50  along the central axis  11  can be implemented by an external driving device (not shown) connected to the second light-blocking sleeve  70 . 
         [0043]    As shown in  FIG. 3 , light rays propagating from the light source  20  in direction A or in a direction which forms with the central axis  11  an included angle greater than the included angle between direction A and the central axis  11  are blocked by the bottom light-blocking sleeve  10   a  of the reflector  10  or the second light-blocking sleeve  70  and therefore will not be projected out of the light exit opening  12  of the reflector  10  (the line segments drawn in dashed lines and marked with X represent light ray sections which would have existed if not blocked). 
         [0044]    Referring again to  FIG. 3 , light rays propagating from the light source  20  in direction B or in a direction which forms with the central axis  11  an included angle less than the included angle between direction A and the central axis  11  and greater than the included angle between direction C and the central axis  11  impinge on and are blocked by the second light-blocking sleeve  70  and therefore will not be projected out of the light exit opening  12  (the line segments drawn in dashed lines and marked with X represent light ray sections which would have existed if not blocked). 
         [0045]    With continued reference to  FIG. 3 , light rays propagating from the light source  20  in direction C are modulated by the movable lens  50  while passing therethrough, but the modulate light rays are blocked by the first light-blocking sleeve  40  and therefore will not be projected out of the light exit opening  12  (the line segments drawn in dashed lines and marked with X represent light ray sections which would have existed if not blocked). 
         [0046]    Referring to  FIG. 3  again, light rays propagating from the light source  20  in a direction which forms with the central axis  11  an included angle less than the included angle between direction C and the central axis  11  and greater than or equal to the included angle between direction E and the central axis  11  are modulated by the movable lens  50  while passing therethrough, and yet the modulated light rays are blocked by the first light-blocking sleeve  40  and therefore will not be projected out of the light exit opening  12  (the line segments drawn in dashed lines and marked with X represent light ray sections which would have existed if not blocked). 
         [0047]    Referring again to  FIG. 3 , light rays propagating from the light source  20  in a direction which forms with the central axis  11  an included angle less than or equal to the included angle between direction E and the central axis  11  impinge on the movable lens  50  and are modulated by the movable lens  50  while passing therethrough. Then, the modulated light rays impinge on the fixed lens  30  and are modulated thereby into a broad beam  60 ′, which is projected out of the light exit opening  12 . 
         [0048]    In summary, when the zoom spotlight  100  is in the configuration shown in  FIG. 3 , the relative positions of the movable lens  50  and the fixed lens  30  are such that a portion of the light projected from the light source  20  is blocked by the bottom light-blocking sleeve  10   a  of the reflector  10  or the second light-blocking sleeve  70 . Meanwhile, a portion of the light projected from the light source  20  is modulated by the movable lens  50  and is projected to and blocked by the first light-blocking sleeve  40 . On the other hand, light rays which are modulated by the movable lens  50  and subsequently projected to and modulated by the fixed lens  30  are cast out of the light exit opening  12  as the broad beam  60 ′. 
         [0049]    In the embodiment described above, the behavior of the movable lens  50  and the fixed lens  30  combined is the behavior of an equivalent positive lens. 
         [0050]    Referring now to  FIG. 4  and  FIG. 5 , the light exit opening  12  of the reflector  10  of the zoom spotlight  100  is further covered with a light-permeable plate  80 , which ensures that operation of the zoom spotlight  100  will not be affected by water drops or other foreign matter which may otherwise enter the reflector  10  through the light exit opening  12 . It is understood that the bottom side  13  of the reflector  10  can also be covered with a covering element (not shown) to prevent water drops or other foreign matter from entering the reflector  10  through the bottom side  13 . 
         [0051]    In addition, as shown in  FIG. 6  and  FIG. 7 , the zoom spotlight  100  further has a heat dissipation mechanism  90  connected to the light source  20 . The present invention imposes no limitations on the size or material of the heat dissipation mechanism  90 , provided that the heat dissipation mechanism  90  can increase the area of heat dissipation from the light source  20  and does not interfere with operation of the zoom spotlight  100 . In the embodiment shown in  FIG. 7 , the zoom spotlight  100  has the heat dissipation mechanism  90  as well as the light-permeable plate  80 . 
         [0052]    It can be known from the foregoing embodiments that the movable lens  50  of the zoom spotlight  100  can be moved along the central axis  11 . When the movable lens  50  is close to the fixed lens  30 , light rays which are modulated by the movable lens  50  while passing therethrough and which subsequently impinge on and are modulated by the fixed lens  30  are cast out of the light exit opening  12  as the collimated beam  60 , thanks to the relative positions of the movable lens  50  and the fixed lens  30 . 
         [0053]    When the movable lens  50  is moved closer to the light source  20 , light rays which are modulated by the movable lens  50  while passing therethrough and which subsequently impinge on and are modulated by the fixed lens  30  are cast out of the light exit opening  12  in a diverging manner, forming a beam ranging between the collimated beam  60  in  FIG. 2  and the broad beam  60 ′ in  FIG. 3 . 
         [0054]    When the movable lens  50  is moved to a position even closer to the light source  20 , light rays which are modulated by the movable lens  50  while passing therethrough and which subsequently impinge on and are modulated by the fixed lens  30  are cast out of the light exit opening  12  as the broad beam  60 ′, thanks to the relative positions of the movable lens  50  and the fixed lens  30 . 
         [0055]    In the foregoing embodiments, the first light-blocking sleeve  40 , the second light-blocking sleeve  70 , or the bottom light-blocking sleeve  10   a  of the reflector  10  provides blockage of light such that no rays of light emitted by the light source  20  can be directly projected out of the light exit opening  12 . 
         [0056]    The embodiments described above are intended only to demonstrate the technical concept and features of the present invention so as to enable a person skilled in the art to understand and implement the contents disclosed herein. It is understood that the disclosed embodiments are not to limit the scope of the present invention. Therefore, all equivalent changes or modifications based on the concept of the present invention should be encompassed by the appended claims.