Not Applicable.
This application relates to binoculars, specifically to controlling the amount of visual parallax perceived by a human observer when using a pair of binoculars.
Binoculars or binocular telescopes are a pair of identical telescopes mounted side-by-side and aligned to point accurately in the same direction. Binoculars allow the viewer to use both eyes when viewing distant objects. Furthermore, binoculars give viewers a three-dimensional image: for nearer objects the two views, presented to each of the viewer's eyes from slightly different viewpoints, produce a merged view with an impression of depth.
Binoculars are used by hunters, bird watcher, and other nature enthusiasts. By design, binoculars are intended for viewing distant objects. However, it will be desirable if the viewer can use his binoculars not only for viewing distant objects but also for viewing objects as close as one meter. This will allow the viewer to use his binoculars for observing many interesting objects such as outdoor plants, flowers, butterflies, dragonflies, etc.
Humans have two eyes with overlapping visual fields that use parallax to gain depth perception. Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the convergence angle between those two lines. Nearby objects have a larger parallax than more distant objects.
When an object at a close distance is viewed through binoculars, parallax may become too large. This is because the apparent convergence angle, i.e. the angle of the light beams exiting from the right and left eyepiece lenses, is magnified by the binoculars. For example, when an observer views an object at a distance of one meter using binoculars having a magnification of 10×, the observer needs to turn his eyes inward (make the eye axes converge) so much as if viewing an object at a distance of 10 cm. This excessive parallax greatly strains the observers eyes. In such a situation, many people simply cannot merge the right and left images into one.
Several approaches have been taken in the prior art to reduce the excessive parallax produced by binoculars when viewing close objects. U.S. Pat. No. 4,264,122 issued on Apr. 28, 1981 to Schmidt et al. teaches a binocular telescope wherein the angle between left and right telescopes' optical axes can be adjusted using an articulating hinge mechanism. An alternative solution is disclosed in U.S. Pat. No. 6,134,048 issued on Oct. 17, 2000 to Kato et al. wherein the excessive convergence angle is corrected by a mechanism that decanters an element of the objective lens system.
While it is advantages to reduce parallax when viewing nearby objects, in some other applications it might be desirable to increase the parallax between the left and right images. For instance, when observing objects located several hundred meters or more, increasing parallax helps provide an enhanced three-dimensional viewing experience. It is also possible to increase the horizontal field of view of binoculars by making the left an right telescopes have divergent fields of view.
The present invention introduces a novel solution for correcting or adjusting the convergence angle in binocular telescopes: A pair of wedge prisms are introduced in the optical path of the left and right telescopes to optically steer their fields of view. Parallax correction can be applied to binoculars' real field of view (objective end) or to their apparent filed of view (eyepiece end).
In accordance with one embodiment, a pair of wedge prisms are mounted behind the eyepieces of a binocular telescope to bend the direction of the light beams exiting from the two eyepieces. This can help increase or decrease the amount of perceived parallax between left and right images resulting in several desirable features.
The foregoing aspects and many of the attendant advantages of this invention will become more readily apparent with reference to the following detailed description of the invention, when taken in conjunction with the appended claims and accompanying drawings, wherein:
Consider the optical diagram shown in
When observing an object through binoculars, the object is seen at slightly different field angles by the left and right objective lenses. For simplicity, we assume that the object is equally distant from the left and right objective lenses. In this case, it will be seen at the same field angle α (albeit at different sides of the optical axis) by the left and right telescopes. From the point of view of parallax analysis, we call the angle α “real convergence angle”. It is easy to see that α decreases as the object distance increases.
At their eyepiece side, binoculars create two magnified and slightly different images of the object. These differences are represented by the “apparent convergence angle” β. It is this apparent convergence angle that provides information that the brain uses to calculate depth in the visual scene. To a first-order approximation, β=Mα where M is the magnification of the binoculars.
From the above description it is evident that one can control the amount of perceived parallax by manipulating the apparent convergence angle β, the real convergence angle α, or both. In the present invention we use thin wedge prisms to control the angles α or β without any change to the original collimation state of the binoculars. Several preferred embodiments of the invention are discussed next.
A first embodiment of the invention is shown in
A second embodiment of the invention is shown in
A further advantage of the configuration shown in
A third embodiment of the invention is shown in
Optionally, this embodiment of the invention may include a second pair of wedge prisms 5 and 6 mounted in a second pair of housing means 9 and 10. The housing means 9 and 10 are designed such that they can be detachably mounted onto a binoculars 25 such that the wedge prism 5 and 6 are positioned behind the eyepiece lenses 3 and 4. Furthermore, the housing means 9 and 10 are designed to position the wedge prism 5 and 6 such that either their apexes face each other or their bases face each other.
The housing means 9, 10, 11, and 12 may be made using rubber or other elastic material so that they fit firmly on the body of an existing binocular. Alternatively, they may have clamps, magnets or other suitable means to detachably mount them onto the binoculars. In addition, the housing means 11 and 12 may include a hinge or joint to connect them together. Similarly, the housing means 9 and 10 may be connected together using a suitable joint as well. Persons skilled in the art of mechanical engineering would be familiar with designing and making suitable detachable housing means according to the invention.
The first pair of wedge prisms 15 and 16 and the second pair of wedge prisms 5 and 6 may be used together or separately. They can be designed to increase parallax or decrease it as desired by the user.
The present embodiment has the advantage that it can be attached to an existing binoculars.
Based on the above descriptions of the invention, a number of advantages over prior art are readily apparent:
The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention.
While the above descriptions of the present invention contain numerous specificities, they should not be construed as limiting the scope of the invention, but as mere illustrations of some of the preferred embodiments thereof. Many other ramifications and variations are possible within the expositions of the various embodiments. For example:
Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teachings and guidance presented herein.
It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance presented herein, in combination with the knowledge of one of ordinary skill in the art. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, as opposed to the embodiments illustrated.
Number | Name | Date | Kind |
---|---|---|---|
3524702 | Bellows | Aug 1970 | A |
4217048 | Egawa | Aug 1980 | A |
4264122 | Schmidt et al. | Apr 1981 | A |
4518231 | Muchel | May 1985 | A |
4717239 | Steenblik | Jan 1988 | A |
4779965 | Beecher | Oct 1988 | A |
6134048 | Kato et al. | Oct 2000 | A |
20100188744 | Hengst | Jul 2010 | A1 |
20130093857 | Yanagita | Apr 2013 | A1 |
20140168381 | Wada | Jun 2014 | A1 |
20140177043 | Togino | Jun 2014 | A1 |
Number | Date | Country | |
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20160266371 A1 | Sep 2016 | US |