Abstract:
An optical sight of the present invention may aim at an object via a cross. The optical sight has a focusing adjuster for focusing and a brightness adjuster for adjusting luminance on a cross. The focusing adjuster and the brightness adjuster are made at the same position that user may operate the optical sight more conveniently.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to an optical device, and more particularly to an optical sight. 
         [0003]    2. Description of the Related Art 
         [0004]      FIG. 1  shows a conventional optical sight  100  including a barrel  110 , on which a focusing adjuster  120  and a brightness adjuster  130  are provided, to provide a clearly view of an object when the user aims the optical sight  100  at the object. 
         [0005]    However, the focusing adjuster  120  and the brightness adjuster  130  are provided at different positions of the barrel  110  that the user has to shift his/her hand between the focusing adjuster  120  and the brightness adjuster  130  for several times to operate them repeatedly before the user may get a clear view of the object through the optical sight  100 . In aiming, the user looks at the optical sight  100  by one eye and keeps the other eye open to pay attention to other stuffs around. However, sometime, the optical sight  100  may block the view of the eye that the user could aware of the accident immediately when he/she is aiming through the optical sight  100 . 
         [0006]    In conclusion, the conventional optical sight  100  still has some drawbacks to be improved. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary objective of the present invention is to provide an optical sight, which has the focusing adjuster and the brightness adjuster at the same position. 
         [0008]    According to the objective of the present invention, the present invention provides an optical sight including a barrel; a lens assembly received in the barrel; a lens with a cross received in the barrel; a light emitting device received in the barrel to emit light to the lens to light the cross up; a focusing adjuster, which is provided at the barrel, including a focusing knob rotating along a center of rotation to move at least a lens of the lens assembly along an optical axis for focusing when the focusing knob is turned; a brightness adjuster, which is provided at the barrel, including a brightness knob rotating along the center of rotation to change a luminance of the light emitting device when the brightness knob is turned; and a power source electrically connected to light emitting device through the brightness adjuster. 
         [0009]    The present invention further provides an optical sight including a barrel; a lens assembly received in the barrel; a lens with a cross received in the barrel; a light emitting device received in the barrel to emit light to the lens to light the cross up; a focusing adjuster, which is provided at the barrel, including a focusing knob rotating along a first center of rotation to move at least a lens of the lens assembly along an optical axis for focusing when the focusing knob is turned; a brightness adjuster, which is provided at the barrel, including a brightness knob rotating along a second center of rotation to change a luminance of the light emitting device when the brightness knob is turned; and a power source electrically connected to light emitting device through the brightness adjuster. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of the conventional optical sight; 
           [0011]      FIG. 2  is a perspective view of a first preferred embodiment of the present invention; 
           [0012]      FIG. 3  is an exploded view of the first preferred embodiment of the present invention; 
           [0013]      FIG. 4  is a sectional view of in part of the first preferred embodiment of the present invention; 
           [0014]      FIG. 5  is a sectional view of the first preferred embodiment of the present invention; and 
           [0015]      FIG. 6  is a perspective view of a second preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    As shown in  FIG. 2  to  FIG. 4 , an optical sight  1  of the preferred embodiment of the present invention includes a barrel  10 , a focusing adjuster  20 , a brightness adjuster  30 , and a power source  40 . 
         [0017]    The barrel  10  has a body  11 , a first base  12 , and a second base  13 . The body  11  has an opening  111  thereon, and has a lens assembly, a frame  51 , a lens  52  with a cross at a center thereof, and a light emitting device  53 . The lens assembly includes a plurality of lenses  54  mounted on the frame  51 . The frame  51  is provided with an axle  511  inserted into the opening  111 . The light emitting device  53  is a LED in the present invention to light the cross of the lens  52  up. 
         [0018]    The first base  12  is fixed to the body  11  by bolts  60 . The axle  511  of the frame  51  is inserted into the first base  12  through the opening  111  of the body  11 . The first base  12  further has a bore  121  on a sidewall thereof. The second base  13  is fixed to the first base  12  by bolts  61 . An O ring  14  is provided between the first base  12  and the second base  13  to protect the second base  13 . 
         [0019]    The focusing adjuster  20  includes a focusing cam  21 , and a focusing knob  22 . The focusing cam  21  is received in the first base  12 . As shown in  FIG. 5 , the focusing cam  21  has a side  211  facing the body  11  and has a slot  212  on the side  211  to be engaged with the axle  511  of the frame  51 . The slot  212  is curved and has an end proximal to a center of the side  211  and the other end distal to the center thereof. The focusing knob  22  is provided on an outer side of the first base  12  to be turned along an axle. The focusing knob  22  has a shaft  23  passing through the bore  121  of the first base  12  to connect the focusing cam  21  that the frame  51  may be moved by turning the knob  50  through the shaft  23  moves along the slot  212 . The frame  51  carrying the lenses  54  is moved along an optical axis of the lenses  54  for focusing. 
         [0020]    The brightness adjuster  30  includes a section elastic member  31 , a main circuit board  31 , a brightness knob  33 , and a brightness control circuit board  34 . The section elastic member  31  is provided on the main circuit board  32 . The main circuit board  32  has three pads  321  to be connected to the light emitting device  53  through a flexible printed circuit board  35 . The section elastic member  31  and the main circuit board  32  are fixed to the second base  13  by bolts  62 . The brightness knob  33  is provided on an outer side of the second base  13 . The brightness knob  33  and the focusing knob  22  are turned along the same shaft. The section elastic member  31  is engaged with an inner side of the brightness knob  33  that the section elastic member  31  may stop the brightness knob  33  at predetermined positions and sound clicks remind the user. The section elastic member  31  is a well known art, so we do not describe the detail here. The brightness control circuit board  34  is connected to the brightness knob  33  to be turned along with the brightness knob  33 . The brightness control circuit board  34  has several different resistors electrically connected to the pads  321  respectively. 
         [0021]    The power source  40  is a battery. An electrode plate  41 , a ring  42 , and a lid  43  are mounted on the brightness adjuster  30  to receive the battery  40  therein and connect the battery  40  to the brightness control circuit board  34  to provide power to the light emitting device  53 . 
         [0022]    User may turn the brightness knob  33  to turn the brightness control circuit board  34 . It may change the resistance between the power source  40  and the light emitting device  53  through the pads contacting with different resistors to adjust the luminance of the light emitting device  53 . It may provide several LEDs to emit different color lights to the lens  52 . User may choose a suitable color light according to the background of the object that user may see the object more clearly through the optical sight  1  of the present invention. 
         [0023]      FIG. 6  shows an optical sight  2  of the second preferred embodiment of the present invention, which is similar to the first preferred embodiment, except that a focusing adjuster  70  has a focusing knob  71 , which is turned along a first center of rotation, and a brightness adjuster  80  has a brightness knob  81 , which is turned along a second center of rotation. The focusing knob  71  and the brightness knob  81  are independent that user may turn focusing knob  71  and the brightness knob  81  respectively to adjust the focusing and brightness. 
         [0024]    An alternate design of the focusing adjuster and the brightness adjuster is that the brightness adjuster is more proximal to the body than the focusing adjuster. 
         [0025]    Except for the circuit of the present invention for the brightness adjuster  30  to adjust the luminance thereof, it may provide a variable resistor to change the resistance to provide a stepless control of the luminance of the LED. 
         [0026]    The first base  12  and the second base  13  may be made into a single element, and furthermore, the body  11 , the first base  12  and the second base  13  may be made into a single element. 
         [0027]    The description above is a few preferred embodiments of the present invention, and the equivalence of the present invention is still in the scope of claim construction of the present invention.