Abstract:
A reticle for an optical sighting device, such as a riflescope, has subtension markings of varying thicknesses and scales to accommodate both stationary and moving targeting.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to optical sighting devices for use with firearms. More particularly, the present invention relates to a reticle for use in an optical sighting device. 
       BACKGROUND 
       [0002]    Riflescopes and reticles are changing continuously as shooting changes and technology develops. There have been a number of recent advances in reticle design, but none have fully resolved all of the problems or limitations in certain types of shooting. 
         [0003]    Typical riflescopes have two focal planes, one in front of the zoom magnification system (that is, the erector system), and the other behind the zoom magnification system. A reticle may be placed at either of the focal planes, and there are advantages and disadvantages related to each. Reticles placed in front of the zoom magnification system are typically called “first focal plane” reticles and those placed behind the zoom magnification system are typically called “second focal plane” reticles. 
         [0004]    The majority of shooters prefer first focal plane reticles. Such reticles and the image viewed through the riflescope will change in size in proportion to one another: as the image gets bigger, the information on the reticle gets bigger at the same rate. One advantage to a first focal plane reticle is that any measurement marks on the reticle will be accurate at any magnification setting the user chooses. As the image is magnified, the information on the reticle appears to get larger along with the image at the same rate, so all reticle markings will be accurate to its designed scale of measurement. Further, the lines which make-up the reticle will get thicker to the user&#39;s eye at higher magnifications, and thinner at lower magnifications. 
         [0005]    In addition, shooters commonly encounter targets that may be either stationary or moving. For moving targets, it is often advantageous to use a lower magnification setting in order to maximize the field of view through the riflescope. For stationary targets, however, large field of view is not nearly as important, so the shooter can take advantage of a higher magnification setting. As a result, a shooter who encounters both types of targets would benefit from having a reticle that provides features that cater to each. 
         [0006]    Many shooters would like to dial their turret for elevation but hold their reticle for windage or for moving targets, rather than dialing for their elevation and windage, which they may do when targeting stationary targets. It is typically easier and faster to dial for elevation than for windage, and many shooters find dialing windage adjustments inefficient when encountering a moving target. 
         [0007]    When shooting at stationary targets, many shooters like having a fine cross for aiming. However, some shooters prefer an “open center” for the main crosshair area of the reticle such as the Vortex EBR-2C reticle. Using connected fine subtension markings and a horizontal stadia line provide multiple fine aiming points along the horizontal axis for a shooter who dials for elevation but holds for windage on a stationary target. 
         [0008]    It is difficult, however, to produce a reticle that works well for both stationary and moving targets where the shooter does not want to dial for windage when tracking a moving target. For example, shooters who want to dial for elevation but hold for windage lose the benefit of having a fine aiming point when not aiming at the exact center crosshair of the reticle. In addition, aiming at moving targets require less fine (coarse) subtension markings, whereas stationary targets need finer subtension marks. 
         [0009]    Another problem with many existing reticles are that the information displayed may be confusing and/or cluttered. For example, some reticles include subtension markings of varying lengths and/or relating to angular measurements in both Milliradians (MRADs) and Minutes of Angle (MOA), making the shooter have to memorize to which graduation the subtension markings relate. 
         [0010]    There is also a trend in sighting devices to have an increased magnification range. It is not uncommon for scopes to have 6× magnification ranges and some scopes even have magnification ranges in the 10× or more range. As magnification ranges increase, it becomes more difficult to optimize the line thickness of reticles used in the first focal plane because there is a much larger change in reticle line size over the magnification range. 
         [0011]    As such, there is a need for a reticle for shooters that prefer to dial for elevation and hold for windage that utilizes both coarse and fine aiming points at the center crosshair as well as along the main horizontal stadia line. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a riflescope optical sighting device in accordance with the present invention; 
           [0013]      FIG. 2  is a cross-section view of the riflescope of  FIG. 1  along line  2 - 2 , showing a moveable optical element inside the scope body; 
           [0014]      FIG. 3  is a schematic view of the erector system in the optical element of an optical sighting device in accordance with the present invention; 
           [0015]      FIG. 4A  is a view through one embodiment of a prior art first focal plane reticle as viewed at a lower magnification setting; 
           [0016]      FIG. 4B  is a view through the first focal plane reticle of  FIG. 4A  as viewed at a higher magnification setting; 
           [0017]      FIG. 5A  is a view through one embodiment of a prior art first focal plane reticle as viewed at a lower magnification setting; 
           [0018]      FIG. 5B  is a view through the first focal plane reticle of  FIG. 5A  as viewed at a higher magnification setting; 
           [0019]      FIG. 6  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting; 
           [0020]      FIG. 7  is a view through the first focal plane reticle of  FIG. 6  as viewed at a lower magnification setting; 
           [0021]      FIG. 8  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting; 
           [0022]      FIG. 9  is a view through the first focal plane reticle of  FIG. 8  as viewed at a lower magnification setting; 
           [0023]      FIG. 10  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting; 
           [0024]      FIG. 11  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting; 
           [0025]      FIG. 12  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting; 
           [0026]      FIG. 13  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting; 
           [0027]      FIG. 14  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting; and 
           [0028]      FIG. 15  is a view through one embodiment of a first focal plane reticle in accordance with the present invention as viewed at a higher magnification setting. 
       
    
    
     SUMMARY 
       [0029]    An optical sighting device includes an objective lens system having a center axis, an eyepiece lens, and an erector lens system forming an optical system having a first focal plane and a second focal plane, the first focal plane proximate the objective lens system, and the second focal plane proximate the eyepiece lens. The optical system has a reticle at the first focal plane. The reticle includes a horizontal stadia line and a vertical stadia line. The reticle also includes a plurality of elevation subtension markings having a thickness and are connected to the vertical stadia line. The reticle also includes a plurality of fine subtension markings having a thickness and are connected to the horizontal stadia line. Finally, the first reticle also has a plurality of coarse subtension markings having a thickness greater than the thickness of the fine subtension markings, and the coarse subtension markings are disconnected from the horizontal stadia line. 
         [0030]    It will be understood by those skilled in the art that one or more aspects of this invention can meet certain objectives, while one or more other aspects can lead to certain other objectives. Other objects, features, benefits and advantages of the present invention will be apparent in this summary and descriptions of the disclosed embodiment, and will be readily apparent to those skilled in the art. Such objects, features, benefits and advantages will be apparent from the above as taken in conjunction with the accompanying figures and all reasonable inferences to be drawn therefrom. 
       DETAILED DESCRIPTION 
       [0031]      FIG. 1  shows an exemplary dual focal plane optical sighting device  10 , having a scope body  12 , objective lens end  40  and eyepiece end  50 .  FIG. 2  shows a cross-section of the sighting device from  FIG. 1  showing the basic components of optical system  14  and moveable optical element  15 . As shown in  FIG. 2 , optical system  14  includes an objective lens system  16 , erector system  25 , and eyepiece  18 .  FIG. 2  shows a riflescope embodiment of the invention having a body  12 , but optical system  14  could be used in other types of sighting devices as well. Erector system  25  may be included within a moveable optic element  15 . In  FIG. 2 , moveable optic element  15  also includes a collector  22 , as well as first focal plane reticle  55  and second focal plane reticle  57 . When in use, adjustment of turret assembly  28  and turret screw  29  causes adjustment of moveable optic element  15 . 
         [0032]      FIG. 3  shows a close-up view of an optical system  14  in cross-section, illustrating how light rays travel through the optical system  14 . Optical system  14  may have additional optical components such as collector  22 , and it is well known within the art that certain components, such as objective lens system  16 , erector system  25 , and eyepiece  18  may themselves have multiple components or lenses. Optical system  14  shown here is drawn as a basic system for illustration of one embodiment of the invention but it should be understood that variations of other optical systems with more or less structural components would be within the scope of the invention as well. 
         [0033]      FIGS. 4A-5B  are views through two very similar embodiments of prior art reticles. In particular, the reticle shown in  FIGS. 4A and 4B  show reticle similar to a Vortex Optics EBR-2C MRAD reticle  100 , and  FIGS. 5A and 5B  show a reticle similar to a Vortex Optics EBR-2C MOA reticle  200  (collectively, the “EBR-2C Family”). The primary difference between the reticle  100  and reticle  200  is the unit of measure used for the subtension markings, which is selected per the shooter&#39;s preference. Although the embodiments shown use MRAD and/or MOA scales, any other suitable scale may be used without departing from the invention. The EBR-2C Family includes a vertical stadia line  102 ,  202  and a horizontal stadia line  104 ,  204 . Elevation subtension markings  106 ,  206  are provided along the vertical stadia line  102 ,  202 . Similarly, windage subtension markings  108 ,  208  are provided along the horizontal stadia line  104 ,  204 . The subtension markings  106 ,  206 ,  108 ,  208  provided in the EBR-2C Family are all of the same fine thickness, and all intersect either the vertical stadia line  102 ,  202  or the horizontal stadia line  104 ,  204 . In addition, the lower half of each EBR-2C Family reticle includes a “Christmas tree” dot pattern  110 ,  210  which provides easy reference points away from the stadia lines  102 ,  202 ,  104 ,  204 . Because each of the subtension markings  106 ,  206 ,  108 ,  208  intersects one of the stadia lines  102 ,  202 ,  104 ,  204 , the EBR-2C Family of reticles is well suited for shooting at stationary targets, but lacks a more coarse set of subtension markings that would be ideal for moving targets. 
         [0034]    Turning now to  FIGS. 6-7 , one embodiment of a reticle  300  in accordance with the invention is shown. Reticle  300  includes units shown in MRAD and includes vertical stadia line  302  and horizontal stadia line  304 . Although the scale used for reticle  300  is MRADs, a similar reticle  400  using MOA for its scale is shown in  FIGS. 8-9 . Reticle  300  also includes a Christmas tree dot pattern  310  on the lower half of the reticle. Reticle  300  provides information that includes subtension markings that aid shooters aiming at both stationary and moving targets, especially when the shooter wants to dial for elevation along vertical stadia line  302 , but hold for wind along horizontal stadia line  304 . In particular, fine subtension markings  306  may be used for aiming at stationary targets and is shown with a fine scale showing 0.2 MRAD increments. Fine subtension markings  306  are connected to the horizontal stadia line  304  to provide multiple fine aiming points along the horizontal axis. Coarse subtension markings  308  are located below horizontal stadia line  304  and are thicker than fine subtension markings  306 . Coarse subtension markings  308  are thicker to allow the shooter&#39;s eye to pick them up more quickly when tracking a moving target, especially at a lower magnification setting.  FIG. 7  shows the view through reticle  300  in such a lower magnification setting and coarse subtension markings  308  are more easily viewed than fine subtension markings  306 . In addition, coarse subtension markings  308  are disconnected from the horizontal stadia line  304  and are shown with a coarse scale showing 0.5 MRAD subtension markings. The coarse subtension markings  308  are disconnected from the horizontal stadia line  304  to allow the fine intersected aiming points of the fine subtension markings  306  to be unobstructed for fine windage aiming points on the top of the horizontal stadia line  304 . The intersected aiming points are not necessary for the relatively coarse aiming required for moving targets. Although the fine subtension markings  306  are shown above the horizontal stadia line  304  and the coarse subtension markings  308  are shown below the horizontal stadia line  304 , the fine subtension markings may alternatively be located below the horizontal stadia line and the coarse subtension markings may alternatively be located above the horizontal stadia line. An example of such a configuration is shown in  FIG. 15 . 
         [0035]    Another advantage of reticle  300  is that the combination of fine subtension markings  306  and coarse subtension markings  308  enhance the readability of both sets of subtension markings that use different scales. For example, in reticle  300 , the fine subtension markings  306  are shown in 0.2 MRAD increments and the coarse subtension markings  308  in shown in 0.5 MRAD increments. It is sometimes difficult to quickly determine which marking the shooter is looking at. The inclusion of a different scale on the bottom actually helps with the determination process. In reticle  300 , it is easy to determine the 0.4 and 0.6 fine subtension markings above the horizontal stadia line  304  because they are to the immediate right and left of the 0.5 coarse subtension markings  308 . Of course, any other suitable scales may also be used with similar effect without departing from the invention. 
         [0036]      FIG. 10  shows another embodiment of a reticle  500  in accordance with the invention. Reticle  500  is shown in MRADs, and has similar markings to reticle  300 , except the christmas tree dot pattern  310  is replaced by a simplified scale  512  shown in 0.5 MRAD increments. Simplified scale  512  also only includes even numbered numerals to reduce clutter on the lower half of reticle  500 . 
         [0037]      FIG. 11  shows another embodiment of a reticle  600  in accordance with the invention. Reticle  600  takes the lower half scale of reticle  500  and adds thick sections  602  to certain parts of the lower scale  612 . The thick sections  602  are shown at 1 MRAD increments, making them easy to find quickly. 
         [0038]      FIG. 12  shows yet another embodiment of a reticle  700  in accordance with the invention. Reticle  700  includes even thicker sections  702  to coarse subtension markings  708 . Coarse subtension markings  708  are disconnected from horizontal stadia line  704 . The thicker sections  702  are shown at 1 MRAD increments and have increased visibility. In an alternative embodiment shown in  FIG. 14 , reticle  900  includes thick sections  902  to coarse subtension markings  908 , but the subtension markings intersect horizontal stadia line  904 . 
         [0039]      FIG. 13  shows another embodiment of a reticle  800  in accordance with the invention. Reticle  800  is similar to reticle  300  in that it includes vertical stadia line  802  and horizontal stadia line  804 , a Christmas tree dot pattern  810  on the lower half of the reticle. Fine subtension markings  806  are connected to the horizontal stadia line  304  to provide multiple fine aiming points along the horizontal axis. Coarse subtension markings  808  are located below horizontal stadia line  804  and are thicker than fine subtension markings  806 . As with reticle  300 , coarse subtension markings  808  are thicker to allow the shooter&#39;s eye to pick them up more quickly when tracking a moving target, especially at a lower magnification setting. Unlike reticle  300 , in which coarse subtension markings  308  are disconnected from the horizontal stadia line  304 , coarse subtension marking  808  are connected to the horizontal stadia line  804 . 
         [0040]    Although the invention has been herein described in what is perceived to be the most practical and preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific embodiments set forth above. Rather, it is recognized that modifications may be made by one of skill in the art of the invention without departing from the spirit or intent of the invention and, therefore, the invention is to be taken as including all reasonable equivalents to the subject matter of the appended claims and the description of the invention herein.