US20200025516A1

US20200025516A1 - Compact reflector sight

Info

Publication number: US20200025516A1
Application number: US16/510,745
Authority: US
Inventors: Kai Yiu Edward Mok
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-07-18
Filing date: 2019-07-12
Publication date: 2020-01-23

Abstract

A low-mounting reflector sight for use on weapons, such as handguns, is introduced. The reflector sight features a semi-reflective mirror surface whose focal point is positioned above the optical axis of the sight. This feature allows the light source (whose virtual image will provide the aiming mark) to be positioned above the optical axis of the sight. The battery compartment, electronic circuits, and brightness control knobs are also positioned above the optical axis of the sight. The sight, therefore, can be mounted very low on a weapon such as a handgun or a rifle. This, in turn, minimizes the parallax between the aiming axis of the sight and the axis of the weapon's barrel and leads to improved aiming.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application Ser. No. 62/700,074, filed 18 Jul. 2018, the contents of which are herein incorporated by reference.

FIELD OF THE INVENTION

This invention pertains to sighting devices used on small arms. More specifically, it relates to a class of non-magnifying optical sights known as reflector sights or red-dot sights.

BACKGROUND

A reflector sight (also called a reflex sight or a red-dot sight) is an optical device that allows the user to look through a partially reflecting glass surface and see an illuminated projection of an aiming point or reticle pattern superimposed on the field of view. These sights use the optical principle that anything at the focus of a lens or curved mirror (such as an illuminated reticle) will look like it is sitting in front of the viewer at infinity. Reflector sights employ some sort of “reflector” to allow the viewer to see the aiming point image and the field of view at the same time, either by bouncing the image created by a lens off a slanted glass plate, or by using a partially-reflective curved glass reflector that images the reticle while the viewer looks through the reflector (See FIG. 1).
Since the reticle is seen at infinity, it stays in alignment with the device the sight is attached to regardless of the viewer's eye position, removing most of the parallax and other sighting errors found in simple sighting devices.
Reflector sights are made in several variations. The common configuration of a compact reflector sights is shown in FIG. 1. With reference to this figure, a half silvered or dichroic curved collimating mirror 2 is positioned at an angle that performs both tasks of focusing and combining the image of an offset light source 4. This type of reflector sight is most often seen as the red-dot type used on small arms. The light source may be shaped in the form of an aiming mark or reticle. It is also possible to place the reticle between the viewer and the curved mirror at the mirror's focus. The reticle itself is too close to the eye to be in focus but the curved mirror presents the viewer with an image of the reticle at infinity.
The viewing portion of a reflector sight does not use any refractive optical elements, it is simply a “red dot” projected off the half-silvered curved mirror right into the user's eye. As a result, a reflector sight does not have the field of view and eye relief problems of telescopic sights (riflescopes). In contrast to a telescopic sight, the field of view of a reflector sight is the user's naked eye field of view. Also, the non-focusing collimated nature of a reflector sight means it doesn't have the optical telescope's constraint of eye relief (Eye relief refers to a specific distance behind the eyepiece of a telescopic sight where the exit pupil is located. Reflector sights do not have an exit pupil and therefore do not have eye relief).
While reflector sights have many advantages, they also have some limitations. They are often used for close quarter combat (CQB) and as such they are susceptible to two types of parallax error:

- A first type of parallax error occurs because the apparent position of the aiming mark (red-dot) is at a distance different than the target distance. As a result, if the user shifts his eye position behind the sight, the aiming mark appears to shift on target.
- A second type of parallax error is introduced due to the optical axis of the sight being located above the axis of the weapon's barrel. As a result, the red-dot and the bullet path coincide only at a set distance (called first zero); at distances before and after this point, the weapon will shoot below or above the aiming point, respectively.

In view of the second parallax error defined above, it would be very desirable to put the optical axis of the sight as close to the axis of the barrel as possible. U.S. Pat. No. 9,010,012 granted to Matthews et al. on Apr. 21, 2015 teaches a reflector sight for use with handguns such that the optical axis of the sight (e.g. the apparent position of the red dot) is co-axial with the axis of the barrel. While this is ideal from the optical point of view, the sight disclosed in this patent poses many practical challenges that limit its utility. For example, the sight must be mounted behind the receiver of a handgun. This would interfere with manual manipulation of the cocking hammer in many popular handguns such as the well-known Colt 1911 model. Another problem with the sight proposed by Matthews et al. is that it is a “blind sight”. That is, the red-dot is presented on a dark background. The shooter must therefore aim with both eyes open and rely on binocular image fusion characteristics of human visual system to superimpose the red dot on the image of the target in his brain.
It is evident from the above review of the state of the art that there is a need for a compact reflector sight that can be readily mounted onto handguns and other small arms such that it provides an aiming mark as close as possible to the axis of the barrel.

SUMMARY OF ONE OR MORE EMBODIMENTS OF THE INVENTION

Advantages of One or More Embodiments of the Present Invention

The various embodiments of the present invention may, but do not necessarily, achieve one or more of the following advantages.
provides a compact sight with a low mount;
the ability to reduce parallax error for a handgun sight;
provides a sight design that is robust and with a clean aesthetic appearance.
These and other advantages may be realized by reference to the remaining portions of the specification, claims, and abstract.

BRIEF DESCRIPTION OF ONE OR MORE EMBODIMENTS OF THE PRESENT INVENTION

This invention teaches a low-mounting reflector sight for use on hand guns, rifles or shotguns. The reflector sight features a semi-reflective mirror surface whose focal point is positioned above the optical axis of the sight. This feature allows the light source (whose reflected image will provide the aiming mark) to be positioned above the optical axis of the sight. The battery compartment, electronic circuits, and brightness control knobs are all positioned above the optical axis of the sight as well.
The above description sets forth, rather broadly, a summary of one embodiment of the present invention so that the detailed description that follows may be better understood and contributions of the present invention to the art may be better appreciated. Some of the embodiments of the present invention may not include all of the features or characteristics listed in the above summary. There are, of course, additional features of the invention that will be described below and will form the subject matter of claims. In this respect, before explaining at least one preferred embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of a common type of prior art reflector sight.

FIG. 2 shows a front perspective view of the reflector sight according to an embodiment of the present invention.

FIG. 3 shows a rear perspective view of the reflector sight according to an embodiment of the present invention.

FIG. 4 shows a rear cut-away view of the reflector sight according to an embodiment of the present invention.

DESCRIPTION OF CERTAIN EMBODIMENTS OF THE PRESENT INVENTION

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part of this application. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
The preferred embodiment of the invention is illustrated in FIGS. 2 through 4. With reference to FIG. 2, the compact reflector sight comprises a housing 5 which has an elongated boxlike shape with its front and rear sections being open so that light from the target can enter the housing from the front end (shown on the left side in FIG. 2) and exit from the rear end (shown on the right side in FIG. 2). The housing is attached to the base 1 which provides a means for attaching the reflector sight to the top side of a weapon's receiver via standard rail systems such as Weaver Rail or Picatinny Rail.
The boxlike shape of the housing 5 has side walls and a top wall. The top wall has an outer top surface and an inner top surface.
A curved semi-transparent mirror 2 is positioned at the front end of the housing 5. This mirror is designed such that it allows most of the light arriving from the target to pass through it without any noticeable aberration or dispersion. The top wall of the housing 5 has a thickness for housing a battery compartment 6 and associated electronics. This allows for the battery compartment to be easily accessible by the shooter. Similarly, brightness control knobs 3 are positioned in the side wall near the top surface of the sight such that they are easily accessible by the shooter yet they are away from the optical path of the sight. (See FIGS. 2 and 3). The housing 5 has a substantially flat outer top surface so that the battery compartment 6 is flush and smooth with the housing. The battery cover is also flush with the top surface. Similarly, the control knobs 3 are integrated smoothly into the sides of the housing 5 but adjacent the thickness of the top wall that provides the circuitry housing so that all the electronics of the sight 1 are readily contained in the top battery compartment. The housing 5 thus provides substantially clean lines for a nice aesthetic appearance.
The optical layout of the compact reflector sight in accordance to the preferred embodiment of the invention is shown in FIG. 4. With reference to this figure, an artificial light source 4 is positioned at the focal point of the curved semi-transparent mirror 2. Furthermore, the curved semi-transparent mirror 2 is mounted such that its focal point is positioned above its optical axis. This allows for the artificial light source 4 to be attached from the inner top surface adjacent the top of the housing 5 within the hollow interior.
The light source 4 may comprise a Light Emitting Diode (LED) or a similar electric light. It is powered by a small battery (not shown) and its brightness is controlled via an electronic circuit (not shown). Furthermore, a reticule pattern or pinhole may be attached to the light source 4 such that it provides an illuminated pattern in the form of a circle, a cross or any other pattern suitable for use as aiming mark. Designing an electronic circuit to control the brightness of an LED is well-known in the art and is not discussed here. Persons skilled in the art of designing reflector sights will be familiar with designing a suitable control circuit to suit the present invention.
The compact reflector sight disclosed in this invention has several advantages:

- Since the light source and all the electronic circuits are positioned at the top of the housing, the sight can be mounted very low on the receiver of a weapon. This in turn minimizes parallax error while aiming at near targets.
- Since the focal point of the semi-reflective mirror is above the optical axis, any glare and unwanted light reflection from the metal surfaces on the gun (e.g. top surface of the receiver) will not be reflected back towards the shooter's eye. This improves image contrast.
- The battery compartment, brightness knobs and other adjustment knobs that can produce glare and unwanted reflections are all positioned at the top of the housing away from the optical axis of the semi-reflecting mirror. This arrangement not only improves image contrast as mentioned above, but also makes it much easier for the shooter to access the battery compartment and the knobs.

HOW TO USE THE INVENTION

To use the compact reflector sight disclosed in this invention, the user must first install the sight on his weapon's receiver such that the base 1 is firmly attached to the top of the receiver and the optical axis of the sight is aligned with the axis of the barrel.
To aim his weapon, the user should look through the sight from its rear end. He will see a reflection of the artificial light source imaged to infinity by the semi-reflective mirror. This image (which appears in the form of an illuminated red-dot or other suitable shapes) will constitute the aiming mark of the sight. The shooter should hold the weapon such that the aiming mark is aligned with the target.
The phraseology or terminology used in this specification 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.
The foregoing description reveals the general nature of the invention clearly and fully such that others can, by applying knowledge within the skill of the art, readily build and use the invention. For brevity, only essential aspects of the invention that differ in significant ways from the prior art are described and illustrated. Persons skilled in the art will know how to design the semi-reflective mirror 2 suitable for the invention. They would also know how to design suitable electronic circuits to power the light source 4 and to control its brightness.
The compact sight according to the present invention may also include position adjustment means for the artificial light source 4 such that it can be shifted precisely in horizontal and vertical directions to help align the aiming mark with the axis of the weapon's barrel. Again, persons skilled in the art of making reflector sights will be familiar with such aspects.
It will be understood by the person skilled in the art that terms of orientation such as top, bottom, front, back, left, right, inner, outer, etc. are used herein with reference to the drawings in order to provide a clear and concise description. Such terms are not intended to limit the examples and embodiments in any manner and the scope of the invention as defined herein will encompass other possible orientations of the components as will be perceived by the person skilled in the art.
Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the embodiments of this invention. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents rather than by the examples given.

Claims

What is claimed is:

1. A reflector sight for use on a weapon, such as a handgun, comprising:

(A) a housing, said housing having a hollow interior, an open front end, an open rear end, a top wall having a top inner surface within the hollow interior;

(B) a curved semi-reflective mirror surface, said mirror surface providing a focal point and an optical axis, said mirror surface being mounted at the front end of said housing such that said focal point is positioned:

(a) above said optical axis; and

(b) at or near the top inner surface of said housing; and

(C) an artificial light source, said artificial light source being positioned at the focal point of said mirror surface;

(D) whereby a shooter who has positioned his eye behind the rear end of said housing can see a reflection of the light emitted from said artificial light source and use it as an aiming mark.

2. The reflector sight of claim 1 further including a battery compartment, said battery compartment being located within the top wall of the housing.

3. The reflector sight of claim 2 wherein a battery cover of the battery compartment is flush with a top outer surface of the top wall.

4. The reflector sight of claim 1 further including one or more brightness control knobs for adjusting the light intensity of said artificial light source, said brightness control knobs being attached to said housing at a position above the optical axis of said mirror surface.

5. The reflector sight of claim 1 wherein said artificial light source comprises an LED.

6. The reflector sight of claim 1 wherein the artificial light source is attached adjacent the top of said housing.