Patent Application
20200292277
A “viewfinder” in archery may refer to a “peep” style viewfinder that is commonly mounted on the bow string, or the forward sight that is mounted to the bow riser. In either case, light reflecting off of a smooth surface of the viewfinder can produce glare, inhibiting its use. Reflected light follows the fundamental principles of physics that define the angle of reflected light to be equal to the angle of the incoming incident light. Thus, a longer continuous smooth surface on the viewfinder provides a greater surface area to reflect light, causing more and/or brighter glare for the user.
With traditional viewfinders, various lighting conditions cause glare based on the surface geometries of these viewfinders. The simple fix for glare is to provide a light shade. Early light shades were smooth cylindrical tube extensions forward and aft of the main body/structure of the viewfinder(s). This was an improvement but glare was still an issue. To combat glare in a tube-shaped viewfinder, conical shapes were introduced which reduce glare while simultaneously enabling a larger field if the viewfinder were to rotate or twist relative to the line of sight 12.
However, even these conical surfaces, when misaligned (rotated about their geometric center 14) compared to their intended geometry relative to the line of sight 12, still can generate stray light. Rotation of the viewfinders can be caused by the string 8 twisting and the bow 13 torquing about the handle. If either viewfinder has forward 30 or aft 32 flat continuous surfaces, the result will be glare 31 and 33 propagated to the user resulting in a less than clear observed target 10 scene. When glare is present in an optical system, the observed target scene can be unresolvable causing accuracy of the user to suffer.
Both cylindrical and cone geometries help, but still do not fully address the issue of glare. Incident light impinging on the inside of the viewfinder may still generate glare 31, 33, as illustrated in
Viewfinders having conical shapes provide an angled surface so that the reflected light is directed further away from the user's eye to reduce glare. This is illustrated by
For a viewfinder mounted in a bow string, the string can twist, resulting in a misalignment of these surfaces from their intended geometry relative to the target (e.g., axially aligned to the line of sight to the target). Likewise for the front or “scope” viewfinder mounted in a bow system, when the bow is drawn back, the bow may twist or rotate due to the asymmetric forces applied to the cable guard. This rotation or twist can also misalign the forward viewfinder. Either viewfinder with smooth surfaces may create unintended geometries that can result in stray light as viewed by the user/archer at low angle of incidence light rays.
In an example, the archery viewfinder enables coaxial alignment with a target, where the front and rear of the viewfinder provide light baffles to block unwanted incident stray light from combining with the observed target scene.
Before continuing, it is noted that the examples described herein are provided for purposes of illustration, and are not intended to be limiting. Other devices and/or device configurations may be utilized to carry out the operations described herein. The operations shown and described herein are provided to illustrate example implementations. The operations are not limited to the ordering shown. Still other operations may also be implemented.
It is also noted that as used herein, the terms “includes” and “including” mean, but is not limited to, “includes” or “including” and “includes at least” or “including at least” The term “based on” means “based on” and “based at least in part on.”
The term “baffle” as used herein means, but is not limited to a ring surface that is substantially orthogonal to the line of sight and has a diameter larger than the smallest aperture/field stop (generally near the geometric center of the viewfinder) in an optical system where a groove (multiple shapes) where the feature with the largest diameter is greater than the field stop and the baffle diameter.
The viewfinder 6 has a geometrically parallel shape (e.g., a polygon or cylinder) in combination with light baffles to provide the best performing anti-glare viewfinder under all geometries that may be implemented by an archery bow system. As such, the archery viewfinder disclosed herein with a forward and aft sections and cylindrical baffled features eliminate glare from being observed by the user. The light baffles effectively redirect incident (off-axis) light generally away from the user.
A forward section of the viewfinder 6, as that term is used herein, refers to the front surface 50 of the viewfinder 6 where the opening aperture diameter 52 is equal to the innermost diameter 56. Where innermost diameter 56 is defined as the end of the cylinder shape formed by propagating the aperture diameter 52 axially until it intersects with an inner surface 72. Where a minimum of one annular groove 51 has a diameter that is greater than the opening aperture 52 and the field stop 70. Additional annular rings 53 and 55 along with baffles 54 and 56 are a function of the length of the forward section (i.e. the longer the sectional length, the more annular rings and grooves necessary to minimize reflected/stray light.)
An aft section of the viewfinder 6, as that term is used herein, refers to the aft surface 60 of the viewfinder 6 where the opening aperture diameter 62 is equal to the innermost diameter 66. Where innermost diameter 66 is defined as the end of the cylinder shape formed by propagating the aperture diameter 62 axially until it intersects with an inner surface 74. Additional annular rings 61, 63, and 65 along with baffles 64 and 66 are a function of the length of the forward section (i.e. the longer the sectional length, the more annular rings are necessary to eliminate the stray light.)
In an example, a third section of the viewfinder 6, as that term is used herein, refers to the intersection of the propagated cylinders of the forward section aperture 52 and aft section aperture 62 as they intersecting with the first inner surfaces 72 and 74. Where the aperture diameter 70 is smaller than the forward aperture 52 and aft aperture 62.
As noted above, other configurations of the archery viewfinder disclosed herein are also contemplated.
Still other configurations of the archery viewfinder disclosed herein are also contemplated, as will be readily understood by those having ordinary skill in the art after becoming familiar with the teachings herein.
By way of further non-limiting illustration,
These light baffle features can be a part of the archery viewfinder itself. In another example, these features may be provided as a separate element 82 of a viewfinder 6 to include an optical lens 80 that is installed in the body or the viewfinder. In an example, the body has thread 90 and the component has complimentary threaded feature 91. These modular viewfinders can be used with or without a lens 80 depending on the application. In any case, the light baffle is defined by the diameter 96 and the larger diameter defining the groove 98.
It is noted that the examples shown and described are provided for purposes of illustration and are not intended to be limiting. Still other examples are also contemplated.
This application claims the priority benefit of U.S. Provisional Patent Application No. 62/816,896 filed Mar. 11, 2019 for “Archery View Finder,” of Andrew W. Munsell, hereby incorporated by reference in its entirety as though fully set forth herein.
| Number | Date | Country | |
|---|---|---|---|
| 62816896 | Mar 2019 | US |
