Patent Publication Number: US-2006010762-A1

Title: Optical sight with rangefinder and assembly method for the same

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to an optical sight and assembly method for the same, and more specifically, to a telescopic optical sight capable of rangefinding and assembly method for the same.  
      2. The Related Art  
      In general, an optical system of conventional telescopic sight comprises an objective lens assembly, an erector lens assembly, an eyepiece lens assembly and a scale board with a reticle. The scale board is marked with a rough rangefinding scale. A shooter can rapidly estimate the range to a target by referring to the rangefinding scale. Therefore, such conventional telescopic sight may be used as a simple rangefinder.  
      However, the range estimation of conventional telescopic sight is mostly depended on the user&#39;s experience that may likely bring a larger tolerance. Accordingly, a telescopic sight progressively takes the precise shooting and rangefinding fields. A conventional telescopic sight has been disclosed in U.S. Pat. No. 5,771,623 issued on Jun. 30, 1998. The conventional telescopic sight mainly comprises an objective lens assembly, a laser transmitter (like a laser diode, LD), a laser receiver (like an avalanche photoelectric diode, APD), a range indicator (like a light emitting diode, LED) and three sets of prisms, erector lens unit and eyepiece lens unit which are provided with a dichroic coating. The laser transmitter and the laser receiver both constitute a rangefinder of the telescopic sight. The laser rangefinder operates on a principle of measuring a travel period from emission of a laser pulse or laser pulse sequence by the laser transmitter, via pulse reflection with a target aimed at, to a reflected pulse reception by the laser receiver. One half of the value that this travel period is multiplied by the light speed constant yields the distance between the rangefinder and target. The distance calculation is performed by a calculation device or program disposed within the telescopic sight.  
      Generally, several components adapted for conventional telescopic sight, like the objective lens unit, erector lens unit, rangefinding device and eyepiece lens unit, are modularized, individually, and each one is assembled and adjusted respectively into a barrel and then adjusted again after assembled. As the conventional telescopic sight disclosed in U.S. Pat. No. 5,771,623, the erector lens unit thereof is firstly assembled generally, and then fixed on a fabrication fixture for adjusting a position of a reticle to reach a first image plane. Thereafter, the erector lens unit is mounted within a laser rangefinding unit, and the photoelectric rangefinding functions provided with coordination among the laser transmitter, laser receiver and range indicator are adjusted. The complete-adjusted laser rangefinding unit, the objective lens unit, an adjusting mechanism and a power supply unit are disposed into the barrel, respectively. The parallax of the objective lens unit is adjusted after assembled. Meanwhile, if any lens or the reticle becomes contaminated or slanted, each component should be detached from the barrel for adjusting each component before assembled again. Eventually, the eyepiece lens unit can be assembled with the barrel for accomplishing the assembly of the telescopic sight. A quality control procedure, including an optical performance inspection, a photoelectric rangefinding performance inspection, an impact strength inspection and an air-sealing inspection etc., is processed for the finished telescopic sight. If there is any performance varied within the need of re-adjusting, as aforementioned that any lens or the reticle becomes contaminated or slanted, each component should be detached from the barrel and then adjusted before assembled again. Obviously, each step in the assembly of the conventional telescopic sight, i.e. adjusting and assembling, must be repeated if there is any misstep appearing in the assembly. Understandingly, the assembly procedure of the conventional telescopic sight is more complicated and unfavorable to both the cost and manufacturing.  
      For above reasons, it is necessary to provide an optical sight and an assembly method thereof for simplifying the assembly procedure and improving the productibility.  
     SUMMARY OF THE INVENTION  
      An object of the present invention is to provide an optical sight with rangefinder capable of easily facilitating adjustment during assembling and the quality assurance procedure after assembled by way of simplifying the assembly procedure and improving the productibility thereof.  
      Another object of the present invention is to provide an assembly method of an optical sight with rangefinder capable of facilitating adjustment and the quality assurance procedure after assembled for reducing re-assembled procedures and improving the productibility thereof.  
      According above objects of the present invention, there is provided an optical sight with rangefinder comprising an erector lens unit, a photoelectric rangefinding unit, a barrel, an objective lens unit, a plurality of adjusting elements, a power supply unit and an eyepiece lens unit disposed on the barrel. The photoelectric rangefinding unit includes a laser emitter, a laser receiver and a range indicator. The photoelectric rangefinding unit is formed with a tunnel inside passed through therein for containing the erector lens unit. The barrel is a hollow barrel which is formed with a cavity passed through therein axially for containing the erector lens unit. A plurality of openings are formed on sidewall of the barrel corresponding to the positions of the laser emitter, laser receiver and range indicator for conducting the cavity to outside the barrel. The objective lens unit is disposed on one end of the barrel and the eyepiece lens unit is disposed on the other end of the barrel. The adjusting elements are disposed on the barrel corresponding the positions connected with the objective lens unit for adjusting the status of the objective lens unit.  
      The assembly method of the optical sight in accordance with the present invention comprises the steps below: 
          STEP 1: assembling the erector lens unit, the photoelectric rangefinding unit and the barrel formed with a plurality of openings, an objective lens unit and an adjusting element into a first assembly;     STEP 2: adjusting the objective lens unit and the erector lens unit of said first assembly to meet the requirements of the parallax and the point of impact (POI) performances;     STEP 3: adjusting the position of the reticle to reach the image plane of the objective lens unit or the image plane of erector lens unit and then fixing the position of the reticle;     STEP 4: adjusting the focus of the laser emitter and the laser receiver and adjusting the position of the range indicator of the first assembly to meet the requirement of the photoelectric rangefinding performance;     STEP 5: assembling the eyepiece lens unit to an end of the barrel of the first assembly;     STEP 6: assembling the optical filtering unit to position in front of the objective lens unit;     STEP 7: a quality test procedure will be implemented after aforementioned assembling steps. The quality test procedure includes an optical performance test, a photoelectric rangefinding performance test, an impact strength test and an air-sealing performance test. The assembling process will be returned to step 1 if any defect found in the quality test procedure;     STEP 8: sealing the openings of the barrel by utilizing a plurality of sealing sheets thereby completing assembly of the optical sight with rangefinder.        

      In contrast to the prior art, the optical sight according to the present invention comprises the openings disposed on sidewall of the barrel corresponding to the positions of the laser emitter, laser receiver and the range indicator for easily facilitating the adjustment of each element. The optical sight according to the present invention is capable of preventing unnecessary disassemblies and re-assemblies for saving the total assembled time and reducing the number of defective products and the cost of production. The assembly method of the optical sight according to the present invention can be adjusted after all elements are assembled. The assembly method of the optical sight according to the present invention can be used to reduce the adjusting times and prevent unnecessary disassemblies and re-assemblies for simplifying the assembly process and improving the yield rate and the productibility of the laser sight. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments thereof, with reference to the attached drawings, in which:  
       FIG. 1  is an exploded view of an optical sight with rangefinder in accordance with the present invention;  
       FIG. 2  is a perspective view of an objective lens unit and a photoelectric rangefinding unit before assembled;  
       FIG. 3  is a perspective view of the assembled optical sight in accordance with the present invention;  
       FIG. 4  is a right-side view of the optical sight in accordance with the present invention illustrating that the adjustment of the position where the focus of a laser emitter lay in;  
       FIG. 5  is a magnified view of the optical sight shown in  FIG. 4  illustrating that the adjustment of the position where the focus of the laser emitter lay in;  
       FIG. 6  is a left-side view of the optical sight in accordance with the present invention illustrating that the adjustment of the position where the focus of a laser receiver lay in;  
       FIG. 7  is a magnified view of the optical sight shown in  FIG. 6  illustrating that the adjustment of the position where the focus of the laser receiver lay in;  
       FIG. 8  is an upward view of the optical sight in accordance with the present invention illustrating that the adjustment of the position where the focus of a range indicator lay in; and  
       FIG. 9  is a magnified view of the optical sight shown in  FIG. 8  illustrating that the adjustment of the position where the display focus of the range indicator lay in. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following description of the preferred embodiments of the present invention are presented herein for purpose of illustration and description only and it is not intended to be exhaustive or to be limited to the precise form disclosed.  
      With reference to  FIG. 1 , a laser sight according to a preferred embodiment of the present invention, comprises an erector lens unit  1 , a photoelectric rangefinding unit  2 , a barrel  3 , an objective lens unit  4 , adjusting elements  5 ,  51 ,  52 , a power supply unit  6  disposed on the barrel, an optical filter  7  and an eyepiece lens unit  8 . The erector lens unit  1  is served to invert and revert the image produced by the objective lens into a normal way and capable of adjusting the magnification of the optical sight. A reticle served as a reference cross-hair mark for aiming a target is disposed within the erector lens unit  1 . The photoelectric rangefinding unit  2  is a hollow barrel formed as an approximately rectangular shape. A laser emitter  21 , a laser receiver  22  and a range indicator  24  (refer to  FIG. 4  to  FIG. 9 ) are contained inside the photoelectric rangefinding unit  2  and a reflecting prism (not shown) collocating with the laser emitter  21 , the laser receiver  22  and the range indicator  24  is also disposed therein. The reflecting prism includes a reflecting surface for reflecting a light with a predetermined wavelength and allowing other light with other wavelengths to pass. The power supply unit  6  provides an electrical power to generate the rangefinding function. In addition, the photoelectric rangefinding unit  2  is formed with a tunnel  20  passed through therein for containing aforementioned erector lens unit  1 . Generally speaking, in the preferred embodiment according the present invention, the laser emitter  21  may be a laser diode (LD), the laser receiver  22  may be an avalanche photoelectric diode (APD) and the range indicator  23  may be a light emitting diode (LED) panel.  
      Please refer to  FIG. 1 . The barrel  3  is a hollow barrel. A cavity  31  is formed inside the barrel  3  and extended through therein axially for containing aforementioned photoelectric rangefinding unit  2 . A first rectangular opening  33  is formed on a right sidewall of the barrel  3  corresponding to the position of the laser emitter  21  of the photoelectric rangefinding unit  2 . A second rectangular opening  32  is formed on a left sidewall of the barrel  3  corresponding to the position of the laser receiver  22  of the photoelectric rangefinding unit  2 . A third rectangular opening  34  is formed on a bottom sidewall of the barrel  3  corresponding to the position of the range indicator  23  of the photoelectric rangefinding unit  2 . The first, second and third rectangular opening  33 ,  32 ,  34  are used to conduct the cavity  31  to outside the barrel  3 . The assembler or user can adjust the rangefinding performance of the optical sight through the openings without detaching the abovementioned elements. Furthermore, a power supply retainer  30  is formed on the sidewall of the barrel  3  for containing and fixing the power supply unit  6 .  
      Please refer to  FIG. 1  to  FIG. 4 . The objective lens unit  4  is disposed on one end of the barrel  3  adjacent to the photoelectric rangefinding unit  2 . The eyepiece lens unit  8  is disposed on the other end of the barrel  3  adjacent to the erector lens unit  1 . The adjusting element  5  and an adjusting element  52  are respectively disposed on the upside surface and right side surface of the barrel  3  corresponding the positions connected with the objective lens unit  4  for adjusting the relative position of the objective lens unit  4 . An adjusting element  51  is disposed on the left side surface of the barrel  3  approximating to the position of the second rectangular opening  32  for adjusting the relative positions of the erector lens unit  1  and the photoelectric rangefinding unit  2 . The optical filter  7  is positioned in front of the objective lens unit  4  for filtering out the light with specific wavelength and visible light which is unfavorable to the observation. The optical filtering lens unit  7  is used to prevent the defects occurring while laser receiver  22  receiving the reflect laser light and the user observing.  
      Please referring to  FIG. 2  and  FIG. 3 . The assembly method of the optical sight with rangefinder in accordance with the present invention comprises the steps below: 
          STEP 1: assembling the erector lens unit  1 , the photoelectric rangefinding unit  2  and the barrel  3  with a plurality of openings  32 ,  33 ,  34 , the objective lens unit  4  and the adjusting element  5  into a first assembly;     STEP 2: adjusting the objective lens unit  4  and the erector lens unit  1  of said first assembly to meet the requirements of the parallax and the point of impact (POI) performances;     STEP 3: adjusting the position of the reticle to reach the image plane of the objective lens unit  4  or the image plane of erector lens unit  1  and then fixing the position of the reticle;     STEP 4: adjusting the focus of the laser emitter  21  and the laser receiver  22  and adjusting the position of the range indicator  23  of the first assembly to meet the requirement of the photoelectric rangefinding performance;     STEP 5: assembling the eyepiece lens unit  8  to an end of the barrel of the first assembly;     STEP 6: assembling the optical filtering unit  7  to position in front of the objective lens unit  4 ;     STEP 7: a quality test procedure will be implemented after aforementioned assembling steps. The quality test procedure includes an optical performance test, a photoelectric rangefinding performance test, an impact strength test and an air-sealing performance test. The assembling process will be returned to step 1 if any defect found in the quality test procedure;     STEP 8: sealing the openings  32 ,  33 ,  34  of the barrel  3  by utilizing a plurality of sealing sheets thereby completing assembly of the optical sight with rangefinder.        

      Following the above description, in step 4, the reticle is positioned at the image plane of the objective lens unit  4  or the image plane of the erector lens unit  1  (i.e. a first focus plane which the focus of the objective lens located in and a second focus plane which the focus of the erector lens unit located in). Generally speaking, the requirement of the parallax performance of the optical sight is that there is no parallax at 100 yards, and the requirement of the POI performance is 1 MOA (minute of angle), i.e. only a tolerance which below one inch can be allowed between the high magnification image and low magnification image at 100 yards. The adjustment of the photoelectric rangefinding performance is mostly implemented by adjusting the positions of the focus of the laser emitter  21  and laser receiver  22  and the range which the range indicator indicates. As shown in  FIG. 4  and  FIG. 5 , the adjustment of the focus of the laser emitter  21  is implemented by adjusting the emitting beam of the laser emitter  21  to align with the center of the reticle and adjusting the focus of the laser emitter  21  to be collinear with the reticle and the focus of the image plane through the first rectangular opening  33  located in the right sidewall of the barrel  3 . The laser emitter  21  can be adjusted along three axes toward the forward and rearward bi-directions (AB direction), the leftward and rightward bi-directions (CD direction) and the upward and downward bi-directions (EF direction). As shown in  FIG. 6  and  FIG. 7 , the adjustment of the focus of the laser receiver  22  is implemented by adjusting the receiving beam of the laser receiver  22  to align with the center of the reticle and adjusting the focus of the laser receiver  22  to be collinear with the reticle and the focus of the image plane through the second rectangular opening  32  located in the left sidewall of the barrel  3 . The laser receiver  22  can be adjusted along three axes toward the forward and rearward bi-directions (AB direction), the leftward and rightward bi-directions (CD direction) and the upward and downward bi-directions (EF direction). As shown in  FIG. 8  and  FIG. 9 , the adjustment of the displaying focus of the range indicator  23  is implemented by adjusting the position of the characters displayed in the range indicator  23  and adjusting the displaying focus of the range indicator  23  to be collinear with the reticle and the focus of the image plane through the third rectangular opening  34  located in the bottom sidewall of the barrel  3 . The range indicator  23  projects an image on the image plane of the objective lens unit  4  or the image plane of the erector lens unit  1 . The range indicator  23  can be adjusted along three axes toward the forward and rearward bi-directions (AB direction), the leftward and rightward bi-directions (CD direction) and the upward and downward bi-directions of elevation (HI direction).  
      As a result of that the opening  33 ,  32 ,  34  are disposed on sidewalls of the barrel  3  corresponding to the position of the laser emitter  21 , laser receiver  22  and the range indicator  23 , the adjustment of each element can be simplified to prevent unnecessary disassemblies and re-assemblies for saving the total assembled time and reducing the number of defective products and the cost of production. The assembly method of the optical sight according to the present invention can be adjusted after all elements are assembled. The assembly method of the optical sight according to the present invention can be used to reduce the adjusting times and prevent unnecessary disassemblies and re-assemblies for simplifying the assembly process and improving the yield rate and the productibility of the laser sight.  
      While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.