Optical telescopes, instantaneous and automatic focusing in optical telescopes, and integration of devices and components in optical telescopes

Abstract

An optical telescope device has an eyepiece and an objective that define an optical axis of the optical telescope. Each of the eyepiece and the objective has one or more lenses. An internal focusing unit (IFU) of the optical telescope device has at least one lens and is located between the objective and a transparent sensitive focusing plane (TSFP). The TSFP is positioned at a fixed location on the optical axis between the eyepiece and the objective. The fixed location is at a pre- assigned focal plane of the objective. A control system of the optical telescope device is functionally associated with the IFU and is configured to actuate the IFU to instantaneously and automatically adjust focus of the optical telescope device based at least in part on the fixed location of the TSFP. In some cases, the IFU includes one or more Alvarez lens sets.

Description

[0001] APPLICATION FOR PATENT

[0002] TITLE

[0003] Optical Telescopes, Instantaneous and Automatic Focusing in Optical Telescopes, and Integration of Devices and Components in Optical Telescopes

[0004] CROSS-REFERENCE TO RELATED APPLICATIONS

[0005] This application claims priority from US Provisional Patent Application No. 63 / 566,290, filed March 17, 2024, whose disclosure is incorporated by reference in its entirety herein.

[0006] TECHNICAL FIELD

[0007] The present disclosure relates to optical systems, and, in particular, it concerns optical telescopes having various features including instantaneous and automatic focusing.

[0008] BACKGROUND OF THE INVENTION

[0009] Optical devices, such as telescopes and binoculars, have long been used to magnify distant objects for better observation. These devices typically rely on a series of lenses and prisms to direct and focus light, allowing users to see distant objects with greater clarity. The Keplerian telescope, a popular design, includes an objective, an inversion system and an eyepiece. The objective and the inversion system provide an upright intermediate image that is relayed to the eyepiece. Achieving precise focus in these devices can be challenging when observing objects at varying distances.

[0010] SUMMARY OF THE INVENTION

[0011] The present disclosure provides optical telescope devices.

[0012] According to one aspect of the present disclosure, an optical telescope device with instantaneous and automatic focusing is provided by employing an internal focusing unit (IFU) that is an assembly of one or more lens that is moveable (displaceable) relative to a transparent sensitive focusing plane (TSFP) that is at a fixed location on an optical axis between an eyepiece and an objective. According to another aspect of the present disclosure, a prism-based inversion unit, which may have an additional prism cemented thereto, is provided along the optical axis, for example between the IFU and the objective. According to another aspect of the present disclosure, an IFU is implemented as a liquid lens or lenses or one or more Alvarez lens sets (or a combination thereof) that do not move along the optical axis to provide instantaneous and automatic focusing and in certain cases correction for diopter and / or astigmatism. According to another aspect of the present disclosure, a camera system having a lens and detector is integrated with the optical telescope device for imaging objects viewed by the optical telescope device in order to provide, among other things, closed-loop feedback for instantaneous and automatic focusing. According to another aspect of the present disclosure, a microprojector arrangement is integrated with the optical telescope device to project an image through the eyepiece of the telescope to provide the viewer with the projected image overlaid on a magnified view of the real scene.

[0013] According to the teachings of an embodiment of the present disclosure, there is provided a telescope device. The telescope device comprises: an eyepiece having one or more lenses; an objective having one or more lenses, the objective and the eyepiece defining an optical axis of the telescope device; an internal focusing unit (IFU) having at least one lens located between the objective and a transparent sensitive focusing plane (TSFP), the TSFP positioned at a fixed location on the optical axis between the eyepiece and the objective, the fixed location is at a preassigned focal plane of the objective; and a control system functionally associated with the IFU and configured to actuate the IFU to instantaneously and automatically adjust focus of the telescope device based at least in part on the fixed location of the TSFP.

[0014] Optionally, the control system is configured to coalesce an image plane of the objective with the TFSP.

[0015] Optionally, the telescope device further comprises: a distance determining unit associated with the control system and configured to determine a distance from the telescope device to an object viewed through the telescope device, and the control system is further configured to actuate the IFU based on the distance determined by the determining measuring unit.

[0016] Optionally, the distance determining unit includes a time-of-flight sensor.

[0017] Optionally, the telescope device further comprises: a miniature camera system having at least one camera lens adjacent to a front end of the objective and having an optical path that is parallel to the optical path of the telescope device, the camera lens is moveable along an optical axis of the miniature camera system so as to assume a plurality of positions along the optical axis of the miniature camera system, and the control system is further configured to actuate the IFU based on sharpness or blurriness of an object imaged by the miniature camera system at the plurality of positions.

[0018] Optionally, the telescope device further comprises: a detector deployed at an edge of a field of view of the TSFP, the detector electrically associated with the control system and configured to sense at least one of sharpness or blurriness of an image at the TSFP, and the control system is configured to actuate the IFU based on signals indicative of the sharpness or blurriness sensed by the detector.

[0019] Optionally, the IFU is moveable along the optical axis, and the control system is configured to actuate the IFU to move along the optical axis relative to the TSFP to a focusing position.

[0020] Optionally, the IFU includes at least one of a liquid lens or an Alvarez lens set.

[0021] Optionally, the telescope device further comprises: an optical inversion unit formed from a pair of prisms, the optical inversion unit located between the objective and the IFU. Optionally, the telescope device further comprises: an additional prism cemented to one of the prisms of the pair of prisms, the optical inversion unit and the additional prism form a prism assembly that provides: i) an optical path from the objective to the eyepiece, and ii) at least one of an optical path from the objective to a camera associated with a surface of the additional prism, or an optical path from a microprojector arrangement associated with a surface of the additional prism to the eyepiece.

[0022] Optionally, the telescope device further comprises: an additional prism cemented to one of the prisms of the pair of prisms; a lens associated with a surface of the additional prism; a detector; and a dichroic mirror aligned with the TSFP and configured to reflect light in a particular wavelength range and transmit light outside of the particular wavelength range, the dichroic mirror, the optical inversion unit, the additional prism, the lens, and the detector are configured such that part of light in the particular wavelength range that exits from the objective traverses through the optical inversion unit toward the dichroic mirror, is reflected by the dichroic mirror back toward the optical inversion unit, traverses through the optical inversion unit toward the additional prism, and passes through the lens so as to form an image on the detector.

[0023] Optionally, the control system is configured to actuate the IFU based on the image formed on the detector.

[0024] Optionally, the telescope device further comprises: an additional prism cemented to one of the prisms of the pair of prisms; a beamsplitter at an interface between the additional prism and the one of the prisms of the pair of prisms; a lens associated with a surface of the additional prism; and a detector, the optical inversion unit, the additional prism, the lens, and the detector are configured such that light that exits from the objective is reflected at an interface between the pair of prisms toward the additional prism, a part of the reflected light is transmitted by the beamsplitter so as to pass through the additional prism and then through the lens so as to form an image on the detector, and a part of the reflected light is reflected by the beamsplitter so as to traverse through the optical inversion unit toward the eyepiece.

[0025] Optionally, the control system is configured to actuate the IFU based on the image formed on the detector.

[0026] Optionally, the telescope device further comprises: an additional prism cemented to one of the prisms of the pair of prisms; and a microprojector arrangement including a projector lens associated with a surface of the additional prism and a microprojector associated with the projector lens, the microprojector arrangement configured to project light corresponding to an image, the optical inversion unit, the additional prism, and the microprojector arrangement are configured such that light projected by the microprojector arrangement passes through the additional prism and traverses through the optical inversion unit toward the eyepiece, and the optical inversion unit is configured such that light that exits from the objective traverses through the optical inversion unit toward the eyepiece.

[0027] Optionally, a surface of the objective that is closest to the TSFP is coated with a coating that reflects light in a particular wavelength range, and the telescope device further comprises: a dichroic mirror obliquely inclined relative to the TSFP and positioned so that centers of the dichroic mirror and TSFP overlap, the dichroic mirror configured to reflect light in the particular wavelength range and transmit light outside of the particular wavelength range; at least one converging lens; and a detector, the dichroic mirror, the at least one converging lens, and the detector are configured such that part of light in the particular wavelength range that exits from the objective is reflected by the dichroic mirror back toward the surface of the objective, is reflected by the surface of the objective back toward the dichroic mirror, is reflected by the dichroic mirror toward the at least one converging lens, and passes through the at least one converging lens so as to form an image on the detector.

[0028] Optionally, the control system is configured to actuate the IFU based on the image formed on the detector.

[0029] Optionally, the telescope device further comprises: a manually adjustable lens located between the objective and the IFU.

[0030] There is also provided according to the teachings of an embodiment of the present disclosure a telescope device. The telescope comprises: an eyepiece having one or more lenses; an objective having one or more lenses; and a prism assembly including: an optical inversion unit located between the eyepiece and the objective, the optical inversion unit formed from a pair of prisms, and an additional prism cemented to one of the prisms of the pair of prisms, the prism assembly provides: i) an optical path from the objective to the eyepiece, and ii) at least one of an optical path from the objective to a camera associated with a surface of the additional prism, or an optical path from a microprojector arrangement associated with a surface of the additional prism to the eyepiece.

[0031] There is also provided according to the teachings of an embodiment of the present disclosure a telescope device. The telescope comprises: an eyepiece having one or more lenses; an objective having one or more lenses; a prism assembly including: an optical inversion unit located between the eyepiece and the objective, the optical inversion unit formed from a pair of prisms, and an additional prism cemented to one of the prisms of the pair of prisms; and a camera associated with a surface of the additional prism, the prism assembly provides a first optical path from the objective to the eyepiece and a second optical path from the objective to the camera.

[0032] There is also provided according to the teachings of an embodiment of the present disclosure a telescope device. The telescope comprises: an eyepiece having one or more lenses; an objective having one or more lenses; a prism assembly including: an optical inversion unit located between the eyepiece and the objective, the optical inversion unit formed from a pair of prisms, and an additional prism cemented to one of the prisms of the pair of prisms; and a microprojector arrangement associated with a surface of the additional prism, the prism assembly provides a first optical path from the objective to the eyepiece and a second optical path from the microprojector arrangement to the eyepiece.

[0033] There is also provided according to the teachings of an embodiment of the present disclosure a telescope device. The telescope comprises: an eyepiece having one or more lenses; an objective having one or more lenses, the eyepiece and the objective defining an optical axis of the telescope device; and an internal focusing unit (IFU) having at least one lens on the optical axis in the optical path between the eyepiece and at least one lens of the objective, the IFU including at least one of a liquid lens or an Alvarez lens set and configured to adjust focus of the telescope device.

[0034] Optionally, the IFU is part of the objective.

[0035] Unless otherwise defined herein, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure pertains. Although methods and materials similar or equivalent to those described herein may be used in the practice or testing of embodiments of the disclosure, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Some embodiments of the present disclosure are herein described, by way of example only, with reference to the accompanying drawings. With specific reference to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the disclosure. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the disclosure may be practiced.

[0038] Attention is now directed to the drawings, where like reference numerals or characters indicate corresponding or like components. In the drawings:

[0039] FIG. 1 is a schematic representation of a telescope device configured for open loop instantaneous and automatic focusing, according to embodiments of the present disclosure;

[0040] FIG. 2 is a schematic block diagram of the telescope device of FIG. 1 ;

[0041] FIG. 3 is a schematic representation of a telescope device configured for closed-loop instantaneous and automatic focusing, according to embodiments of the present disclosure;

[0042] FIG. 4 is a schematic block diagram of the telescope device of FIG. 3; FIG. 5 is a schematic representation of a telescope device having an eyepiece, an objective that has a pre-assigned image plane (focal plane) that defines a transparent sensitive focusing plane (TSFP), a prism-based inversion unit, an internal focusing unit (IFU) between the TSFP and the inversion unit, and electro-mechanical components for instantaneous and automatic focusing, according to embodiments of the present disclosure;

[0043] FIG. 6 is a schematic representation of a telescope that is similar to FIG. 5, but includes a manual focusing lens between the inversion unit and the objective, according to embodiments of the present disclosure;

[0044] FIG. 7 is a schematic representation of a telescope that is similar to FIG. 5, but includes a miniature camera system having a lens and a detector adjacent to the front end of the objective, according to embodiments of the present disclosure;

[0045] FIG. 8 is a schematic representation of a telescope that is similar to FIG. 6, but includes a detector deployed at the edge of the field of view of the TSFP, according to embodiments of the present disclosure;

[0046] FIG. 9A is a schematic representation of a telescope device having a dichroic beamsplitter deployed obliquely relative to the TSFP and so that the centers of the dichroic beamsplitter and the TSFP coincide, according to embodiments of the present disclosure;

[0047] FIG. 9B is an enlarged view of components of the telescope device of FIG. 9A, showing the objective, the dichroic beamsplitter, and a camera system, as well as the traversal of rays from the objective to the camera system via partial reflection from the dichroic beamsplitter;

[0048] FIG. 10 is a schematic representation of a telescope device having an eyepiece, an objective that has a pre-assigned image plane (focal plane) that defines a TSFP, a prism-based inversion unit, an IFU between the TSFP and the inversion unit, an additional prism cemented to one of the prisms of the inversion unit, and a camera system having a lens and detector deployed in association with a surface of the additional prism, according to embodiments of the present disclosure;

[0049] FIG. 11 is a schematic representation of a telescope device with a dichroic mirror deployed between an eyepiece and a movable IFU, and a detector deployed to collect light reflected by the dichroic mirror, according to embodiments of the present disclosure;

[0050] FIG. 12 is a schematic representation of a telescope device having an eyepiece, an objective, a prism-based inversion unit, an additional prism cemented to one of the prisms of the inversion unit, and a camera system having a lens and detector deployed in association with a surface of the additional prism, according to embodiments of the present disclosure;

[0051] FIG. 13 is an enlarged view of components of the telescope device of FIG. 12, showing the inversion unit, the additional prism, and the camera system as well as an additional camera system having a lens and detector deployed in association with the surface of the additional prism, according to embodiments of the present disclosure;

[0052] FIG. 14 is a schematic representation of a pair of telescope devices, each implemented according to FIG. 12, arranged in a binocular configuration, according to embodiments of the present disclosure;

[0053] FIG. 15 is a schematic representation of a telescope device having an eyepiece, an objective that defines a TSFP, a prism-based inversion unit, an IFU between the TSFP and the inversion unit, an additional prism cemented to one of the prisms of the inversion unit, and a microprojector arrangement having a microprojector and a lens deployed in association with a surface of the additional prism, according to embodiments of the present disclosure;

[0054] FIG. 16 is a schematic representation of a telescope device having an eyepiece, an objective that defines a TSFP, a prism-based inversion unit, an IFU between the TSFP and the inversion unit, a prism having a concave pentagonal shape in a two-dimensional plane, and cemented to one of the prisms of the inversion unit, a camera system deployed in association with a first surface of the concave pentagonal shaped prism, and a microprojector arrangement deployed in association with a first surface of the concave pentagonal shaped prism, according to embodiments of the present disclosure;

[0055] FIGS. 17A and 17B are schematic representations of stages of a process for constructing the concave pentagonal prism FIG. 16, according to embodiments of the present disclosure;

[0056] FIG. 18 is a schematic representation of a telescope device having an eyepiece, an objective that defines a TSFP, a prism-based inversion unit, a first liquid lens between the TSFP and the inversion unit, and a second liquid lens between the inversion unit and the objective, according to embodiments of the present disclosure;

[0057] FIG. 19 is a schematic representation of a telescope device having an eyepiece, an objective that defines a TSFP, a prism-based inversion unit, a first Alvarez lens set between the TSFP and the inversion unit, and a second Alvarez lens set between the inversion unit and the objective, according to embodiments of the present disclosure;

[0058] FIG. 20 is a schematic representation of a telescope device having an eyepiece, an objective, a prism-based inversion unit between the eyepiece and the objective, an IFU implemented as a liquid lens or an Alvarez lens set between the inversion unit and the objective, an additional prism cemented to one of the prisms of the inversion unit, a camera system deployed in association with a surface of the additional prism, a processing unit associated with the camera system, and an IFU control system associated with the processing unit and the IFU, according to embodiments of the present disclosure; FIG. 21 is a schematic representation of a telescope device having an eyepiece, an objective that has a pre-assigned image plane (focal plane) that defines a TSFP, a prism-based inversion unit, a liquid focusing lens or Alvarez focusing lens set between the inversion unit and the objective, a detector deployed at the edge of the field of view of the TSFP, and electro-mechanical components for instantaneous and automatic focusing, according to embodiments of the present disclosure;

[0059] FIG. 22 is a schematic representation of a telescope device having an eyepiece, an objective that has a pre-assigned image plane (focal plane) that defines a TSFP, a prism-based inversion unit, a liquid focusing lens or an Alvarez focusing lens set between the inversion unit and the objective, a beamsplitter deployed between the eyepiece and the inversion unit, a detector deployed to collect light reflected by the beamsplitter, and electro-mechanical components for instantaneous and automatic focusing, according to embodiments of the present disclosure; and

[0060] FIG. 23 is a schematic representation of eyepiece having reduced eye relief, according to embodiments of the present disclosure.

[0061] DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] The present disclosure provides optical telescope devices.

[0063] The principles and operation of the optical telescope devices according to the present disclosure may be better understood with reference to the drawings accompanying the description.

[0064] Before explaining at least one embodiment of the disclosure in detail, it is to be understood that the disclosure is not necessarily limited in its application to the details of construction and the arrangement of the components and / or methods set forth in the following description and / or illustrated in the drawings and / or the examples. The disclosure is capable of other embodiments or of being practiced or carried out in various ways.

[0065] By way of introduction, the present disclosure is presented herein with reference to various exemplary embodiments. Even within each of these embodiments, the disclosure includes a number of different aspects (a sampling of which have been briefly referenced above), each of which is believed to be of independent utility and of patentable significance in its own right. However, it should be noted that there is believed to be a particular synergy to implementations that employ combinations of two or more of the aspects of the disclosure together in a single telescope system.

[0066] Referring now collectively to the drawings, FIGS. 1 - 23 schematically illustrate various exemplary optical telescope devices and features thereof according to the teachings of embodiments of the present disclosure. Generally speaking, each optical telescope device (referred to interchangeably herein as “optical device”, “telescope device”, “optical telescope”, or “telescope”) of the present disclosure includes a plurality of optical components, designated 10 in FIGS. 2 and 4, that include at least an eyepiece 12 and an objective 14, that together define an optical axis of the telescope device and create a magnified image of a viewed object. Each of the objective 14 and the eyepiece 12 has a separate positive focal length, and may each be implemented as a single lens or a set of multiple lenses. The telescope devices illustrated and described herein may typically be implemented according to a Keplerian configuration.

[0067] With particular reference to FIG. 1, a telescope device having components for providing instantaneous and automatic focusing, according to embodiments of the present disclosure, is schematically illustrated. The telescope device is shown as deployed relative to an eye 1 (having lens 2 and retina 3) of a viewer (user), showing sample light rays from a scene traversing through the components of the telescope device to the lens 2 and ultimately to the retina 3. A transparent sensitive focusing plane (TSFP) 16 is positioned at a fixed location on the optical axis between the eyepiece 12 and the objective 14, where the fixed location of the TSFP 16 is a focal plane of the objective 14 (i.e., an intermediate focal plane). As will be discussed, the TSFP 16 is used for instantaneous and automatic focusing, and in particular allows for instantaneous and automatic focusing of the telescope device without the eyepiece 12 or the retina 3 playing any role in the focusing. Within the present disclosure, the term “instantaneous”, as used in the context of “instantaneous focusing”, generally refers to focusing that instant or nearly instant as perceived by the human eye.

[0068] The optical components 10 of the telescope device further include an actuatable internal focusing unit (IFU) 18 (that is an assembly of one or more lens), located between the objective 14 and the TSFP 16. The IFU 18 may be positive or negative, and although illustrated herein as a single lens, may be a group of multiple lenses (i.e., the lens 18 is at least one lens) which may be positive or negative lenses, or may be an assembly of both positive and negative lenses.

[0069] An IFU control system (hereinafter “control system”) 20 is functionally associated with the IFU 18, and is configured to actuate the IFU 18 to automatically adjust focus of the telescope device based at least in part on the fixed location of the TSFP 16. In other terms, the control system 20 is configured to coalesce an image plane of the objective 14 with the TFSP 16 to achieve instantaneous and automatic focusing.

[0070] In certain embodiments, the IFU 18 is a moveable (i.e., displaceable) lens, that is moveable (i.e., laterally displaceable) along the optical axis in the space confined between the objective 14 and the TSFP 16. In such embodiments, the control system 20 is operative to actuate the IFU 18 to move along the optical axis relative to the TSFP 16 (but still between the objective 14 and the TSFP 16) to automatically adjust focus of the telescope device. In other embodiments, which will be discussed in further detail below with particular reference to FIGS. 18 - 21, the IFU 18 is implemented as one or more liquid lens or one or more Alvarez lens set (or combination thereof). In such embodiments, the IFU 18 is in a fixed position on the optical axis (i.e., does not move along the optical axis), and actuation of the IFU 18 creates either a shape change (in the case of liquid lenses) or phase plate translation (in the case of Alvarez lens sets).

[0071] Parenthetically, it is noted that the instantaneous and automatic focusing in the disclosed embodiments is applied through the center of the field of view (which is typically defined by the objective 14). When the field of view contains several objects at various distances from the telescope device, the instantaneous and automatic focusing mechanism focuses on the image of the object that is in the center of the field of view. This factor coincides with the user’s natural tendency to place the region of interest in the center of the field of view. To this end, in the discussion of some of the following embodiments, and in some of the corresponding drawings, a center field of view and edge field of view sample rays are shown traversing through the optical components of the telescope device. It should be understood, however, that additional rays, which span the entire field of view, also traverse through the optical components of the telescope device.

[0072] In conventional focusing techniques in optical telescopes, the focusing takes place after the beam of light from the scene (i.e., the object viewed by the telescope device) passes through the eyepiece. In contrast, in the focusing techniques according to the teachings of the present disclosure the instantaneous and automatic focusing takes place after the beam passes through the objective 14 but before the beam reaches the eyepiece 12. This location of the focusing is enabled by the particular fixed location of the pre-assigned TSFP 16 between the eyepiece 12 and the objective 14, specifically the TSFP 16 being located at the rearmost focal plane of the objective 14 closest to the eyepiece 12. In addition, the optical path length from the vertex of the most frontal surface of the objective 14 to the TSFP 16 is fixed and does not change. Accordingly, the rearmost plane that takes part in the fast automatic focusing process according to the teachings of the present disclosure is a pre-assigned TSFP, rather than the viewer’s retina 3. The pre-assignment of the location of the TSFP 16 on the optical axis is selected based on the specific distance of the viewed object, and therefore may differ from one application to another. For example, the pre-assigned location of the TSFP 16 on the optical axis of two identical optical telescopes would not be the same if one telescope is configured to primarily magnify objects at a distance of 1,000 meters away, and the other telescope is configured to magnify objects at a distance of 5 meters away.

[0073] In certain embodiments, for example as illustrated in FIG. 2, the control system 20 may include, for example, a microcontroller (or driver circuit) 22 and an actuator 26 electrically associated with the microcontroller 22 and functionally associated with the IFU 18. The actuator 26 may be a mechanical actuator, an electromechanical actuator, or any other suitable type of motorized actuator (e.g., voice coil motor / actuator). In embodiments in which the IFU 18 is a moveable lens, the actuator 26 is configured to be driven by the microcontroller 22to act upon the IFU 18 so as to drive / move the IFU 18 to a focusing position along the optical axis. In embodiments in which the IFU 18 is implemented as one or more liquid lens, the actuator 26 may be implemented, for example, as a voice coil that induces a shape change in the liquid lens when a current is driven through the voice coil. In embodiments in which the IFU 18 is implemented as one or more Alvarez lens set, the actuator 26 is configured to be driven by the microcontroller 22to act upon phase plates of the Alvarez lens set so as to shift the phase plates one with respect to another. A more detailed discussion of actuation of the liquid lenses and Alvarez lens sets will be provided below with reference to FIGS. 18 - 21.

[0074] In embodiments in which the IFU is a set of multiple focusing lenses, the control system 20 may include a corresponding multiple number of actuators (one per lens).

[0075] According to certain embodiments, and with reference to FIG. 2, the telescope device may provide open-loop instantaneous and automatic focusing by employing a distance determining unit 30 that is functionally associated with (or may be a part of) the control system 20. In FIG. 2, arrows indicate interconnection and / or logical flow from one component to another. The distance determining unit 30 is configured to determine a distance from the telescope device to an object viewed through the telescope device, and in particular an object at the center of the scene viewed through the telescope. In certain embodiments, the distance determining unit 30 may include a time-of-flight sensor, deployed adjacent to the front side of the objective 14, so that the distance determining unit 30 is configured to measure a distance from the telescope device to an object viewed through the telescope device (based on light from the object that is sensed / detected by the distance measuring unit 30). In other embodiments, the distance determining unit 30 may include a focus sensitive camera system (coupled with a processing unit) that enables determination of the distance from the telescope to the object based on the focus of the camera. The control system 20 may actuate (e.g., move) the IFU 18 based on the distance determined by the distance determining unit 30. In further detail, the distance determining unit 30 determines the distance from the telescope to the viewed object within a few microseconds. The optical axis of the distance determining unit 30 is very close and parallel to the optical axis of the telescope device, and therefore the optical axis of the distance determining unit 30 and the optical axis of the telescope device are aimed at the center of the field of view. The distance determined by the distance determining unit 30 may be processed (by the distance determining unit 30) and converted to a suitable format and sent (or relayed) to the microcontroller 22. In certain embodiments where the IFU 18 is a moveable lens, the microcontroller 22, based on the determined distance, calculates an appropriate position for the IFU 18 to which to move the lens 18 relative to the TSFP 16 to achieve focusing. After calculating the appropriate position of the IFU 18 on the optical axis of the telescope device, the microcontroller 22 may command (for example via electrical signal transmission) the actuator 26 (which may be a voice coil motor) to move the IFU 18 to the appropriate location.

[0076] In certain embodiments, the position to which the IFU 18 is to move along the optical axis is derived from a focusing table, which may be pre-configured during manufacturing of the telescope device. For example, the focusing table can be configured (built-up) by viewing objects in focus on the TSFP 16 through the objective 14 at certain specific distances (e.g., 5 meters, 6 meters, 7 meters, 8 meters, etc.).

[0077] The instantaneous and automatic focusing process, that begins with measuring the distance to an object (by the distance determining unit 30) and ends with having the IFU 18 placed at the correct position relative to the TSFP 16, takes less time than the adjustment of the human eye to focus on objects at various distances. Therefore, the viewer, when looking through the telescope device, continuously sees a focused image on the TSFP 16.

[0078] In certain embodiments, a one-off alignment may be performed to merge the focal plane of the eyepiece 12 with the TSFP 16. The alignment may be performed by the user, for example by moving the eyepiece 12 along the optical axis (for example by turning a knob mechanically linked to the eyepiece 12) in order to see a sharp image at the TSFP 16. After performing this one- off alignment, no further adjustment of the eyepiece 12 is needed for focusing, and the eyepiece 12 does not play any role in the focusing process.

[0079] FIG. 3 illustrates a variation of the telescope device of FIG. 1 , in a configuration to provide closed-loop instantaneous and automatic focusing. Additional reference is made to FIG. 4, which shows a block diagram of some of the components of the telescope device of FIG. 3, with arrows indicating interconnection and / or logical (data) flow and / or control flow from one component to another. Here, the distance determined by the distance determining unit 30 may be used to provide initial instantaneous and automatic focusing (as in the open-loop case described above), but further adjustment of focus may be provided by employing a miniature camera system 40 (having a lens 42 and a detector / sensor 44) in combination with a processing unit 50 that performs image analysis and may also execute autofocus algorithms. The camera lens 42 is moveable along an optical axis of the camera 40 so as to assume a plurality of positions along the optical axis of the camera 40. The control system 20 may move the IFU 18 based on sharpness (or blurriness) of an object imaged by the camera 40 at one or more positions of the plurality of positions. In further detail, the camera 40 and its lens 42 are adjacent to the front end of the objective 14, and the optical path of the camera 40 is parallel to the optical path of the telescope device. Thus, the optical path of the camera 40 is also aimed at the center of the field of view. The lens 42 of the camera 40 may be moveable on an axial mechanism (for example based on a voice coil motor). The lens 42 may move back and forth along an axis that is parallel to the optical axis of the telescope device. In certain embodiments, the processing unit 50, which includes at least one computerized processor coupled to a memory, may analyze the image imaged by the camera 40 in order to determine the sharpness and / or blurriness of the image. The processing unit 50 may then independently actuate the lens 42 to autofocus the image on the detector 44 (which generates data / signals) on the basis of the evaluated sharpness / blurriness. The processing unit 50 may then send this data / signals to the control system 20 (microcontroller 22) to actuate the IFU 18. In certain embodiments, the processing unit 50 may execute computer readable instructions to generate a table of the various locations of the lens 42 on the axis, correspondingly with the various distances in which various objects appear sharp to image analysis algorithms on the detector 44. In certain embodiments, the autofocus algorithms, executed by the processing unit 50, may feed the data in the table to the microcontroller 22, which uses the table data to determine a position to which the IFU 18 is to be moved to refine the focus, and then controls the actuator 26 to move the IFU 18 to the determined position of coalescing with the TSFP. The camera system 40 may repeatedly and continuously capture images and sense the prime focus plane of the object being viewed by the telescope device, and these images / sensor data may be provided to the processing unit 50 as input for the autofocus algorithms, the output of which is fed to the microcontroller 22 to control the actuator 26 to repeatedly move the IFU 18 to adjust the focus.

[0080] In another embodiment of a closed-loop configuration, a transparent window or dichroic mirror (or other planar optical element) having a reticle (e.g., cross hair) may be placed at the TSFP 16. The optical element with reticle is not shown in FIG. 3, but a telescope having a reticle will be discussed in subsequent sections with reference to FIGS. 9A, 9B, and 11. In such closed- loop configurations, the camera system 40 may be deployed to image the reticle (generate image data therefrom). The camera system 40 may provide the image data corresponding to the imaged reticle to the processing unit 50 or the control system 20, which may compare the image of the reticle (which is typically a sharp image because the physical object of the reticle is located on the TSFP 16) with the image of the viewed object, in order to assess the sharpness and / or blurriness of the viewed object in the center of the field of view. Based on the assessed sharpness and / or blurriness, the control system 20 may actuate the IFU 18 to automatically adjust the focus.

[0081] Other closed-loop instantaneous and automatic focusing configurations are contemplated herein, and will be discussed in further detail in subsequent sections of this document.

[0082] FIG. 5 shows another telescope device according to embodiments of the present disclosure. Here, a prism-based optical inversion unit 60 (herein after “inversion unit”) is provided in the optical path between the IFU 18 and the objective 14, and provides an optical path from the objective 14 to the eyepiece 12. Thus, in embodiments in which the IFU 18 is moveable, the IFU 18 moves along the optical axis between the TSFP 16 and the inversion unit 60. The inversion unit 60 functions to invert or revert or erect the image received by the eye 1 at the eyepiece 12, depending on the orientation of the inversion unit 60. In the illustrated embodiment, the orientation of the inversion unit 60 is such that image inversion is provided.

[0083] The inversion unit 60 is formed from a pair of prisms (i.e., first and second prisms) 70 and 80. The first prism 70 has a plurality of surfaces, including surfaces 72, 74, 76, and 78. The second prism 80 also has a plurality of surfaces, including surfaces 82, 84, and 86. The surfaces 72 and 82 may be mutually parallel, and parallel to the TSFP 16, whereas the surfaces 74, 78, 84 may be obliquely inclined (at different oblique angles) relative to the TSFP 16. The two prisms 70 and 80 are optically coupled together at surfaces 76 and 86, which are mutually parallel and obliquely inclined relative to the TSFP 16 (the oblique inclination angle may be at a 45° relative to the optical axis). The prisms 70 and 80 are optically coupled to each other so that there is as small gap 90 (which is an air gap) between the prisms 70 and 80 (i.e., between the surfaces 76 and 86).

[0084] In one set of non-limiting implementations, the first prism 70 is implemented as a Bauernfeind prism and the second prism 80 is implemented as a Schimdt prism, such that the inversion unit 60 is a Schmidt-Pechan prism.

[0085] Traversal of the beam of light (hereinafter referred to as “beam” or “light”) from the from the scene (object viewed by the telescope device) through the telescope device, will now be described. The light from the observed scene (or object) passes through the objective 14. The light that exits from the objective 14 then traverses through the inversion unit 60. In particular, the light from the objective 14 enters first prism 70 through the surface 72, is reflected at surface 76 toward the surface 74, is reflected at the surface 74 toward the air gap 90, exits the first prism 70 through the surface 76 and enters the second prism 80 through the surface 86. The light then traverses through the second prism 80, undergoing reflections from the various surfaces 82, 84, 86 of the prism 80, which as shown by the ray tracing in the figure may be multiple reflections from said surfaces, before ultimately exiting the prism 80 (and hence the inversion unit 60) through the surface 82. The light from the inversion unit 60 then passes through the IFU 18 and the eyepiece 12, where it is viewed by the eye 1 (represented in the drawing as an exit plane).

[0086] The reflections of the light at the various prism surfaces are internal reflections, and with the exception of surface 74 (which is coated with a reflective coating) are total internal reflections. It will therefore be appreciated that the prisms 70 and 80 are designed with particular geometries from particular materials so that with the exception at surface 74 the propagating light strikes the relevant surfaces of the prisms 70 and 80 at angles of incidence greater than a critical angle (defined by the refractive index of the prism material and the surrounding medium (e.g., air)), such that the light is totally internally reflected from said surfaces so as to trap the light within the prism. Bearing this in mind, the light from the objective 14 that enters first prism 70 through the surface 72 is totally internally reflected at the surface 76 toward the surface 74, is reflected at the surface 74 back toward the air gap 90, whereupon the light passes through air gap 90 at an angle of incidence that is less than the critical angle so as to be coupled out of the prism 70 and into the other prism 80. This light that enters the second prism 80 is totally internally reflected at surface 82 toward the surface 84, totally internally reflected at the surface 84 toward the surface 86, and totally internally reflected at the surface 86 back toward the surface 82 whereupon the light is further totally internally reflected at the surface 82, and so on. This total internal reflection process may continue until the deflected light that reaches the surface 82 strikes surface 82 at an angle of incidence that is less than the critical angle so as to be coupled out of the prism 80 (and hence the inversion unit 60) toward the eyepiece 12.

[0087] Also shown in FIG. 5 is a sample of the light from the central scene viewed by the telescope device arriving at distance determining unit 30 (which may be a time-of-flight sensor or a focus sensitive camera), which can be used to perform instantaneous and automatic focusing as described above.

[0088] FIG. 6 illustrates a variation of the telescope device illustrated in FIG. 5, in which a conventional, manually driven, focusing lens 28 is provided in the optical path between the TSFP 16 and the objective 14. In the illustrated embodiment, the focusing lens 28 is deployed between the inversion unit 60 and the objective 14. The lens 28 can be moved along the optical axis by an internal focusing mechanism that may be connected to a wheel or other mechanical actuator that is operated by the user to bring the image to the TSFP 16. This mechanism of manual focusing, commonly used in Keplerian telescopes with a prism-based inversion system, enables in most cases a focusing range from infinity to 2 meters. The inclusion of lens 28 may provide the user of the telescope device with a viable backup option for focusing in the event of malfunction of the instantaneous and automatic focusing mechanism of the telescope device.

[0089] It is noted that in order to allow for the instantaneous and automatic focusing mechanism of the telescope device to perform properly, the manual focusing lens 28 should be moved (e.g., via mechanical actuation initiated by the user) to a pre-assigned location on the optical axis. The lens 28 should then stay at that location when operating the telescope device in the instantaneous and automatic focus mode.

[0090] FIG. 7 illustrates another variation of the telescope device illustrated in FIG. 5. Here, miniature camera 40, having detector 44 and lens 42, preferably with a particularly long focal length (e.g., at least 40 mm), is deployed in order to obtain sensitivity to varying distances of objects viewed through the telescope device. The deployment configuration and operation of the camera 40 is similar to as discussed above with reference to FIG. 3. It will be appreciated that although that discussion was in the context of closed-loop automatic focus, the camera 40 may also be deployed to support open-loop automatic focus. The camera 40 and its lens 42 may be used to capture video images and still images, regardless of their role in instantaneous and automatic focusing.

[0091] Turning now to FIG. 8, there is illustrated another variation of a telescope device according to embodiments of the present disclosure that is configured to operate in a closed-loop instantaneous and automatic focusing mode. Here, the telescope device includes distance determining unit 30 (similar to as in FIG. 5), manual focusing lens 28 (similar to as in FIG. 6, and which may be optional), inversion unit 60, and a detector 32. The detector 32, which may be a small matrix detector, is deployed at the edge of the field of view of the TSFP 16. The detector 32 is configured to sense sharpness and / or blurriness of the image at the TSFP 16, and configured to generate signals indicative of (responsive to) the sensed sharpness and / or blurriness. The detector 32 is electrically associated with the control system 20, and may be further configured to provide (send) the generated signals to the control system 20 so that the control system 20 may move the IFU 18 to a focusing position on the optical axis based on the generated signals.

[0092] Referring now to FIGS. 9A and 9B, there is illustrated components of a telescope device according to another embodiment of the present disclosure. For simplicity of presentation, the IFU is not shown in these figures. In the illustrated embodiment, a dichroic mirror 34 is deployed between the objective 14 and the eyepiece 12, at the location of the TSFP 16. The dichroic mirror 34 is obliquely inclined relative to the TSFP 16 and positioned so that it crosses and overlaps and coincides with the TSFP 16 where the TSFP crosses the optical axis. The dichroic mirror 34 may be configured with a reticle (such as a crosshair), and is configured to reflect light in a particular wavelength range and transmit light outside of the particular wavelength range. In one implementation, the dichroic mirror 34 is coated with a coating that maximizes transmission in the visible region of the electromagnetic spectrum, and reflects light of wavelengths in the particular range of 750 nm to 1000 nm. The surface 15 of the objective 14 that is closest to the TSFP 16 may also be coated with an anti-reflective coating that reflects light in the same particular wavelength range (e.g., 750 nm to 1000 nm).

[0093] As illustrated in FIG. 9B, detector 32 and converging lens 36 (which is shown here as a paraxial lens) are deployed to receive light reflected from the dichroic mirror 34. In particular, the dichroic mirror 34, the converging lens 36, and the detector 32 are configured such that part of the light in the particular wavelength range (e.g., 750 nm to 1000 nm) that exits from the objective 14 (shown only partly in the figure as rearmost lens of the objective) is reflected by the dichroic mirror 34 back toward the surface 15 of the objective 14, is reflected by the surface 15 of the objective 14 back toward the dichroic mirror 34, is reflected by the dichroic mirror 34 toward the converging lens 36, and passes through the converging lens 36 so as to form an image on the detector 32. It is noted that the objective 14, and its surface 15, remain in a fixed location, and the objective 14 does not take part in any focusing. In addition, although the converging lens 36 is illustrated as a single lens for simplicity of presentation, the lens 36 may in fact be a group of lenses that correct for optical aberrations. Finally, as mentioned, the detector 32 may convert the light in the particular wavelength range into an image. This image typically covers only the center of the field of view, and is a mirror image of the corresponding part as an “object” on the area of the dichroic mirror 34 where the light undergoes the first reflection from the objective 14.

[0094] Since the dichroic mirror 34 may include a reticle, the image formed on the detector 32 may also contain an image of the reticle. An image processor (such as processing unit 50), or the control system 20, may compare the image of the reticle (which is typically a sharp image because the physical object of the reticle is located on the TSFP 16) with the image of the viewed object, in order to assess the sharpness and / or blurriness of the viewed object in the center of the field of view. Based on the assessed sharpness and / or blurriness, the control system 20 may actuate the IFU 18 to automatically re-adjust the focus (e.g., move the IFU 18 to a refined focusing position).

[0095] FIG. 10 illustrates another embodiment that employs a dichroic mirror 34, but here the dichroic mirror 34 is perpendicular to the optical axis (parallel to the TSFP 16) such that the dichroic mirror 34 and the TSFP 16 coincide (i.e., the dichroic mirror 34 is overlaid at the TSFP 16). In addition, an additional prism 100 is cemented to one of the prisms 70 of the inversion unit 60 so that the inversion unit 60 and the prism 100 together form a prism assembly 500. The prism 100 has a plurality of surfaces, including surfaces 102, 104, 106. The two prisms 70 and 100 are cemented together at surfaces 74 and 102, which are mutually parallel, to form interface 110. A lens 112 is associated with the surface 104 of the prism 100, and a detector 114 is deployed to received light from the lens 112 (where the lens 112 and detector 114 form a camera system).

[0096] In this embodiment, the prism assembly 500 provides (is configured to provide) a first optical path and a second optical path. The first optical path is from the objective 14 to the eyepiece 12, and the second optical path is to a miniature camera system from the dichroic mirror 34 that coincides with the TSFP 16. The inversion unit 60 alone may provide the first optical path, or may cooperate with the prism 100 to provide the first optical path. The inversion unit 60 and the prism 100 cooperate to provide the second optical path. In further detail, the inversion unit 60, the prism 100, the lens 112, and the detector 114 are configured such that light that exits from the objective 14 enters the first prism 70 through surface 72, is reflected toward the surface 74, is reflected at the surface 74 toward air gap 90, exits the first prism 70 through the surface 76 and enters the second prism 80 through the surface 86. The light then traverses through the second prism 80, undergoing reflections from the various surfaces 82, 84, 86 of the prism 80, which as shown by the ray tracing in the figure may be multiple reflections from said surfaces, before ultimately exiting the prism 80 through the surface 82 and passing through the IFU 18. Similar to as discussed above with reference to FIG. 5, with the exception of the reflection from surface 74, the reflections at the prism surfaces are total internal reflections, whereby the light from the objective 14 is totally internally reflected toward surface 74 from which it is reflected at an angle of incidence less than a critical angle so as to exit the prism 70 and enter the other prism 80. The light that enters the second prism 80 is totally internally reflected at surface 82 toward the surface 84, totally internally reflected at the surface 84 toward the air gap 90, and totally internally reflected at the surface 86 back toward the surface 82 whereupon the light is further totally internally reflected at the surface 82, and so on. This total internal reflection process may continue until the deflected light that reaches the surface 82 strikes surface 82 at an angle of incidence that is less than the critical angle so as to be coupled out of the prism 80 (and hence the inversion unit 60) toward the IFU 18.

[0097] The light from the IFU 18 reaches the dichroic mirror 34, where a part of the light that is outside of the particular wavelength range (e.g., visible light, which outside of the 750 nm to 1000 nm range) is transmitted by the dichroic mirror 34 and passes through the eyepiece 12, where it is viewed by the eye 1. The part of the light in the particular wavelength range (e.g., 750 nm to 1000 nm) is reflected by the dichroic mirror 34 back through the IFU 18 so as to re-enter the second prism 80 through surface 82. The light then traverses through the second prism 80, undergoing total internal reflections from the various surfaces 82, 84, 86 of the prism 80, which as shown by the ray tracing in the figure may be multiple reflections from said surfaces, before ultimately exiting the prism 80 through the surface 86 and entering the first prism 70 through the surface 76. In further detail, the light that enters the prism 80 is totally internally reflected at the surface 86 toward the surface 84, totally internally reflected at the surface 84 toward the surface 82, totally internally reflected at the surface 82 back toward the surface 86, whereupon the light is further totally internally reflected at the surface 86, and so on. This total internal reflection process may continue until the deflected light that reaches the surface 86 strikes surface 86 at an angle of incidence that is less than the critical angle so as to exit the prism 80 through the surface 86, and then enter the prism 70 through the air gap 90 and the surface 76.

[0098] The light that enters the prism 70 through the surface 76 then exits the prism 70 through the surface 74 and enters the additional prism 100 through the surface 102, exits the prism 100 through the surface 104 (typically in a direction normal to the surface 104) whereupon the light reaches the lens 112, which forms an image on the detector 114. It is noted that the magnified field of view of the camera (lens 112 and detector 114 combination) is the same as the magnified field of view seen through the eyepiece 12. This identity between the magnified field of view of the camera and as seen by the viewer through the eyepiece 12 is believed to be another innovative aspect of the present disclosure. The lens 112 preferably has a clear aperture diameter, which allows for only the center of the field of view to be transmitted to the detector 114. The rest of the diameter of the beam of the light is blocked. The sharpness and / or blurriness of the image formed on the detector 114 can then be assessed (for example by the processing unit or the control system), and the control system 20 may move the IFU 18 to a refined focusing position based on the assessment.

[0099] Turning now to FIG. 11, there is illustrated another embodiment of a telescope device according the present disclosure. Unlike in the previous embodiments, in the present embodiment there are no practical space constraints on the location of the TFSP 16. Detector 32 is deployed in a configuration that is parallel to the optical axis, and the dichroic mirror 34 is deployed between the TSFP 16 and the IFU 18 at a 45° relative to the optical axis (and relative to the TSFP 16). As in the previous embodiments, the dichroic mirror 34 is provided with a coating that is designed to reflect light in a particular wavelength range (e.g., 750 nm to 1000 nm) and transmit light outside of the particular wavelength range (e.g., visible light).

[0100] Light in the particular wavelength range (e.g., 750 nm to 1000 nm) that emerges from the objective 14 and the IFU 18 is reflected at the dichroic mirror 34 and strikes the detector 32. The light outside of the particular wavelength range (e.g., visible light) that emerges from the objective 14 and the IFU 18 is transmitted by the dichroic mirror 34 through to the eyepiece 12.

[0101] The dichroic mirror 34 and the detector 32 are particularly situated so that the distance from the TSFP 16 to the dichroic mirror 34 and the distance from the detector 32 to the dichroic mirror 34 are equal. Thus, the distance from the dichroic mirror 34 to either image (both transmitted and reflected) is the same.

[0102] It is noted that the principle of the optical setup of the embodiment illustrated in FIG. 11 resembles that of reflex cameras, with a difference being that instead of a moving mirror, the illustrated embodiment uses a fixed in place dichroic mirror 34. It is also noted that the embodiment illustrated in FIG. 11 enables capturing images (both still and video) by the detector 32 at the particular wavelength range, which in the example is the Near Infrared (NIR) spectral range.

[0103] Returning to the embodiment illustrated in FIG. 10, it is noted that one of the features of the embodiment is that the cemented prism 100 enables integration of various accessories with a telescope device into one compact unit, whereby the optical axis of the accessory merges with the optical axis of the telescope device. However, it should be appreciated that integration of accessories is not strictly limited to embodiments with instantaneous and automatic focusing. In some configurations, integration of the cemented prism 100 merely enables compactization into one unit of a system that otherwise would be a cumbersome hybrid of two or three separate devices, without necessitating instantaneous and automatic focusing as described in the previous embodiments. FIG. 12 illustrates an example of such an embodiment, where no IFU is provided (and hence no instantaneous and automatic focusing according to the previously described embodiments, although TSFP 16 is shown for reference).

[0104] In the embodiment of FIG. 12, the two prisms 70 and 100 are cemented together at surfaces 74 and 104, with a beamsplitter 120 provided at the interface between the surfaces 74 and 102. Lens 112 is associated with the surface 104 of the prism 100, and detector 114 is deployed to receive light from the lens 112. In the illustrated embodiment, the inversion unit 60, the prism 100, the lens 112, and the detector 114 are configured such that light that exits from the objective 14 enters the first prism 70 through surface 72 and is reflected from the surface 76 toward the prism 100, in particular toward the surface 74 (and toward the beamsplitter 120). A part of the reflected light is transmitted by the beamsplitter 120, passes through the prism 100 (enters the prism 100 through the surface 102 and exits the prism 100 through the surface 104, whereby the optical axis of the beam is typically in a direction normal to the surface 104), whereupon the light reaches and passes through the lens 112, which forms an image on the detector 114.

[0105] Another part of the light is reflected by the beamsplitter 120 toward surface 76 so as to traverse through the inversion unit 60 toward the eyepiece 12. In particular, this reflected light exits the first prism 70 through the surface 76 and enters the second prism 80 through the surface 86, and traverses through the second prism 80, undergoing total internal reflections from the various surfaces 82, 84, 86 of the prism 80, which as shown by the ray tracing in the figure may be multiple reflections from said surfaces, before ultimately exiting the prism 80 through the surface 82 (all similar to as discussed above with reference to FIG. 5). The light then passes through the eyepiece 12, where it is viewed by the eye 1.

[0106] Preferably, the dimensions of the prism 100 are minimal, and the height of the prism 100 is equal (or approximately equal) to the heights of the prisms 70 and 80. Furthermore, it is noted that the surface 74 of the first prism 70 that forms part of the interface at which the beamsplitterl20 is located does not support total internal reflection. The beamsplitter 120 preferably has a high reflection to transmission ratio, typically on the order of 98% reflection to 2% transmission. Accordingly, roughly 2% of the intensity of the beam from the objective 14 is transmitted through the beamsplitter 120 toward the detector 114, whereas roughly 98% of the intensity of the beam of light from the objective 14 is reflected toward the inversion unit 60, whereupon it is inverted and transmitted to the eyepiece 12.

[0107] The beamsplitter may be implemented in various ways. For example, the beamsplitter may be implemented by providing a beamsplitter coating on the majority or all of at least one of the surfaces 74 and 104. The beamsplitter 120 may also be implemented as a dichroic beamsplitter. In a preferred embodiment, the prisms 70 and 100, as well as the lens 112, are constructed from glass materials that can optionally support transmission of light at various spectral ranges according to the specific application, including, for example, NIR, SWIR, MIR, LIR, etc., in order to obtain a variety of spectral data from observed objects at the detector 114.

[0108] One significant advantage of the embodiment illustrated in FIG. 12 is that the optical track of the magnifying optical device is kept unchanged and remains as originally designed. Thus, the embodiment of FIG. 12 can be also realized as a retrofit to any existing optical magnifying device that contains a prism-based inversion unit, such as a Schmidt-Pechan prism. Moreover, the integrated camera (lens 112 with detector 114) of this embodiment is of small dimension (similar to the cameras used in cellular telephones) and thus, if needed, the space provided by a small camera allows for placement of two cameras, each sensing a spectral range. FIG. 13 illustrates an example of such an embodiment, which is similar to the embodiment illustrated in FIG. 12, but which includes a second camera (i.e., a second lens 112’ with detector 114’). The cameras are preferably configured to sense / image light in different respective spectral ranges. For example, one of the lens-detector combinations may be configured to sense / image light in a first spectral range (e.g., the visible region of the electromagnetic spectrum) and the other lens-detector combination may be configured to sense / image light in a second spectral range that is different from the first spectral range (e.g., the NIR region, the SWIR region, etc.).

[0109] It will be appreciated that the telescope devices described herein may be used in a monocular configuration, or in a binocular configuration, where a telescope device is provided for each eye. In some binocular devices, the optimal and most compact positioning of two cameras, each on a separate telescope, is on the virtual horizontal axis that crosses the telescopes, parallel to the virtual horizontal axis between the user’s eyes. One example binocular configuration is schematically illustrated in FIG. 14, which is based on the telescope device illustrated in FIG. 12. In fact, the first telescope device (in the upper part of FIG. 14) is identical to the telescope device of FIG. 12, and the second telescope device (in the lower part of FIG. 14) is identical to the first telescope device but reflected about the horizontal axis. In FIG. 14, the components are identified using like reference numerals of the corresponding components of the telescope device of FIG. 12, but with the letter “A” appended to the reference numerals of the first telescope device and the letter “B” appended to the reference numerals of the second telescope device. Thus, as illustrated in FIG. 14, the first telescope device has eyepiece 12A, objective 14A, prism assembly 500A (formed from inversion unit 60A (which is formed from prisms 70A and 80A) and additional prism 100A cemented to prism 70A), and a camera system having lens 112A and detector 114A. Similarly, the second telescope device has eyepiece 12B, objective 14B, prism assembly 500B (formed from inversion unit 60B (which is formed from prisms 70B and 80B) and additional prism 100B cemented to prism 70B), and a camera system having lens 112B and detector 114B. The TSFPs 16A and 16B of the telescope devices are also illustrated.

[0110] Turning now to FIG. 15, there is illustrated another embodiment of a telescope device according the present disclosure which provides augmented reality (AR) and / or virtual reality (VR) functionality. Here, the additional prism 100 allows integration of a microprojector arrangement that includes a projector lens 132 and a microprojector device 130 (e.g., OLED, LCD, LCoS, etc.) that is configured to project a beam of light, corresponding to an image (which may include text), through the prisms 70, 80, 100 and to the TSFP 16, for viewing by the eye of the viewer. The lens 132 is deployed in association with the surface 104 of the prism 100, and directs the beam of light from the microprojector 130 toward the prism 100. The lens 132 may also correct for optical aberrations on the TSFP 16.

[0111] In this embodiment, the prism assembly 500 also provides (is configured to provide) a first optical path and a second optical path, where the first optical path is from the objective 14 to the eyepiece 12, and the second optical path is from the microprojector arrangement to the eyepiece 12. The inversion unit 60 alone (or in cooperation with the additional prism 100) provides the first optical path, and the inversion unit 60 and the prism 100 cooperate to provide the second optical path. It will be noted that the configuration of the inversion unit 60, the prism 100, the microprojector device 130, and the lens 132 is similar to the configuration of the inversion unit 60, the prism 100, the detector 114, and the lens 112 of FIG. 10, and in effect supports propagation of a beam of light along a path that is the reverse of the path of the beam of light that reaches the detector 114 from the dichroic mirror 34 in FIG. 10. In further detail, the inversion unit 60, the prism 100, the microprojector device 130, and the lens 132 are configured such that a beam of light from the microprojector device 130 is directed by the lens 132 into the prism 100 through the surface 104. The beam of light exits the prism 100 through the surface 102 and then enters the prism 70 through the surface 74. The beam of light then passes through the air gap 90 to enter the prism 80, traverses through the second prism 80, undergoing total internal reflections from the various surfaces 82, 84, 86 of the prism 80, which as shown by the ray tracing in the figure may be multiple reflections from said surfaces, before ultimately exiting the prism 80 through the surface 82 (all similar to as described with reference to FIG. 5), then reaches the TSFP 16 and ultimately reaches the user’s eye via the eyepiece 12.

[0112] Concurrently with the traversal of light from the microprojector device 130 to the TSFP 16, light from the scene (object viewed by the telescope device) collected by the objective 14 is inverted by the inversion unit 60 (following a path of traversal similar to as described with reference to FIG. 5). After focusing, both the magnified real image and the projected image reach the TSFP 16, thus providing the viewer with a magnified view of the real scene image together with (e.g., overlaid by) the projected image from the microprojector arrangement.

[0113] The additional prism (e.g., prism 100) that is cemented to the inversion unit 60, for example and is illustrated and described with reference to FIG. 10 and FIGS. 12 - 15, allows for integration of various small-scale devices (e.g., miniature cameras (i.e., lens-detector combinations), microprojector arrangements (e.g., microprojector-lens combinations), etc.) with telescope device via optical coupling with the inversion unit 60. It is noted that regardless of type of device that is integrated, the optical path of the magnification portion of the telescope device is kept unchanged and remains as originally designed. Thus, the concept of integrating such small-scale devices according to the teachings of the present disclosure can be easily realized for any optical viewing device that contains prism assemblies, such as prism-based inversion units (e.g., Schmidt-Pechan prisms), or other prisms.

[0114] It is also noted that the additional prism 100 is illustrated in the drawings as having a triangular shape in the plane of the paper. However, it will be appreciated that this additional prism can be of any suitable shape and is not necessarily confined to the shape illustrated herein, so long as the optical axis of the integrated device (e.g., lens 112, lens 130, etc.) that is associated with the external surface of the prism is normal to that the external surface.

[0115] Turning now to FIG. 16, there is illustrated another embodiment of a telescope device according the present disclosure which supports integration of both a miniature camera (combination of lens 112 and detector 114) and a microprojector arrangement (combination of lens 132 and microprojector device 130). The integration is enabled by attachment of a specially designed compact prism 200 to the inversion unit 60. The prism 200 has a plurality of surfaces, including surfaces 202, 204, 206, 208, 210. In the non-limiting example shown in FIG. 16, the prism 200 has a concave pentagon shape in the plane perpendicular to the TSFP 16 (the plane of the paper), where an obtuse vertex angle is formed at the intersection of surfaces 206 and 208. This prism 200 has a shape that resembles two identical Bauernfeind prisms that are joined at their shortest sides.

[0116] Parenthetically, and with reference also to FIGS. 17A and 17B, in certain embodiments the prism 200 may be constructed from a pair of constituent prisms 200a and 200b. In non-limiting example illustrated here, the constituent prisms 200a and 200b are each four-sided prisms in the plane of the paper, having surfaces 202a, 208, 210, 212a and 202b, 206, 204, 212b, respectively. The constituent prisms 200a and 200b are interfaced (cemented) together at their shortest sides (surfaces) 212a and 212b, such that surfaces 202a and 202b form the surface 202 of the prism 200. The interface 212 (formed by interfacing surfaces 212a and 212b) may extend between the surface 202 and the vertex between surfaces 206 and 208. In the illustrated embodiment, the constituent prisms 200a and 200b are mirror images of each other, and thus the interface between the prisms is normal to the surface 202 and is a perpendicular bisector of the surface 202, such that the interface is an axis of line symmetry of the prism 200.

[0117] Returning to FIG. 16, the prisms 70 and 200 are optically coupled together at surfaces 74 and 202. The inversion unit 60 and the prism 200 together form prism assembly 600. The lenses 112 and 132 are associated with surfaces 206 and 208, respectively (with their optical axes normal to those surfaces).

[0118] In this embodiment, the prism assembly 600 provides (is configured to provide) a first optical path, a second optical path, and a third optical path. The first optical path is from the objective 14 to the eyepiece 12, the second optical path is from the objective 14 to the miniature camera, and the third optical path is from the microprojector arrangement to the eyepiece 12. The inversion unit 60 alone (or in cooperation with the additional prism 100) provides the first optical path, and the inversion unit 60 and the prism 200 cooperate to provide the second and third optical paths.

[0119] The path of traversal of light from the objective 14 to the TSFP 16 (and the eyepiece 12) via the inversion unit 60 (i.e., the first optical path) is similar to as described in previous embodiments and will not be repeated here. The paths of traversal of light from the objective 14 to the detector 114 and from the microprojector 130 to the TSFP 16 (and the eyepiece 12) (i.e., the second and third optical paths), enabled by the configuration of the inversion unit 60, the prism 200, the camera, and the microprojector arrangement, will now be described.

[0120] Light from the objective 14 enters the prism 70 through the surface 72, is reflected by surface 76 away from the air gap 90, exits the prism 70 through the surface 74 and enters the prism 200 through the surface 202, exits the prism 200 through the surface 206, and reaches the lens 112, which forms an image on the detector 114.

[0121] A beam of light corresponding to an image generated by the microprojector device 130 is directed by the lens 132 into the prism 200 through the surface 208. The beam of light exits the prism 200 through the surface 202 and enters the prism 70 through the surface 74. The beam of light then passes through air gap 90 to enter the prism 80, traverses through the second prism 80, undergoing total internal reflections from the various surfaces 82, 84, 86 of the prism 80, which as shown by the ray tracing in the figure may be multiple reflections from said surfaces, before ultimately exiting the prism 80 through the surface 82 (all similar to as described above with reference to FIG. 15), then reaches the TSFP 16 and ultimately reaches the user’s eye via the eyepiece 12.

[0122] Most of the IFU embodiments discussed thus far have been described in the context of a moveable (displaceable) lens, that is moveable / displaceable along the optical axis relative to the TSFP to a focusing position (for example when actuated by control system). However, as mentioned in earlier sections of this document, the actuatable IFU of the telescope devices of the embodiments of the present disclosure may be implemented in various ways besides the moveable lens implementations. Other implementations include, in certain embodiments, liquid lens implementations and / or Alvarez lens set implementations. Therefore, it will be appreciated that in all of the foregoing embodiments, the moveable IFU may easily be replaced by a liquid lens and / or an Alvarez lens set, with modifications for actuation / control as needed. Bearing this in mind, the following sections describe, with reference to FIGS. 18 - 21, several exemplary telescope devices according to the teachings of embodiments of the present disclosure that utilize one or more liquid lens and / or one or more Alvarez lens set for instantaneous and automatic focusing. As will be discussed in further detail below, liquid lenses and Alvarez lens sets provide numerous advantages over conventional moveable focusing lenses.

[0123] By way of introduction, liquid lenses are implemented as cells containing a liquid that is sealed off with an elastic polymer membrane and may be wrapped in a voice coil. Current that is driven through the voice coil produces a magnetic field, which induces a shape change in the membrane (and thus a shape change in the liquid). The shape of membrane / liquid dictates the focal length of the lens, and can be controlled by the amount of current driven through the voice coil. Alvarez lens sets, on the other hand, are implemented using pairs of fixedly spaced apart transmissive refractive phase plates, each having a piano surface and a surface shaped in a two- dimensional free-form profile. The two free-form profiles are identical and are made to be the inverse of each other, so that when both plates are placed with their vertices on the optical axis, the induced phase variations cancel out. However, if the two plates undergo a relative lateral translation, a phase variation is induced that is the differential of the free-form identical surface profiles, resulting in optical power. Relative movements in the x or y direction (directions perpendicular to the general light propagation direction) induce cylindrical power independently in orthogonal directions. Combined movements can produce circular, elliptical, or cylindrical phase profiles. Lateral translation in the x and y directions can be performed via a control mechanism, for example, electronic control, mechanical control, or manual control.

[0124] Bearing the above in mind, attention is now directed to FIG. 18, which illustrates an embodiment of a telescope device according the present disclosure that employs a liquid lens 318a, deployed in a fixed (non-movable) location on the optical axis in the optical path between the inversion unit 60 and the TSFP 16.

[0125] The control system 20 is functionally associated with the liquid lens 318a and is configured to actuate the lens 318a to automatically adjust focus of the telescope device, for example, based on the fixed location of the TSFP 16. In one embodiment, the actuator of the control system may be implemented as, or may be configured to act upon or with, the voice coil wrapped around liquidcontaining cell. The focus adjustment is induced by shape change of the liquid lens 318a in response to controlled actuation by the control system. For example, the microcontroller of the control system may induce (or control another component of the control system to induce) a current to flow through the voice coil to produce the magnetic field that causes the shape change in the liquid lens membrane.

[0126] One significant advantage of utilizing liquid lens 318a as an IFU is that the liquid lens shape-change response time is very fast in comparison to repositioning of a conventional focusing lens along the optical axis, enabling adjustment of the focus for the viewer within a few milliseconds. The adjustment of focus of the liquid lens is also faster than the reaction of the human eye to focus changes, and thus the instantaneous and automatic focus operation, when integrated within a telescope device, provides the viewer with an ever-sharp view of the observed object.

[0127] The liquid lens is also advantageously a compact lens, and has a clear aperture that is typically smaller than 20 mm. Furthermore, the optimal position of the liquid lens within the telescope is in close proximity to the inversion unit 60 where the diameter of the beam of light is smallest. In particular, the distance between the liquid lens and the inversion unit 60 is less than the physical distance between the light entrance and light exit surfaces of the inversion unit 60 (i.e., surfaces 72 and 82). These characteristics of the liquid lens provide additional advantages, and enable a wide range of flexibility with Keplerian telescope configurations.

[0128] In certain embodiments, more than one liquid lens may be deployed to alter the magnification of the telescope and / or to provide the telescope with zoom functionality. For example, the embodiment illustrated in FIG. 18 shows an option of a second liquid lens 318b deployed in another fixed location on the optical axis, for example in the optical path between the objective 14 and the inversion unit 60. The control system 20 may also be functionally associated with the second lens 318b, and configured to actuate the lens 318b to induce the lens shape-change so as to induce focus adjustment of the lens 318b.

[0129] In certain embodiments, such as the embodiment illustrated in FIG. 18, an additional lens 320 (which may be a set of lenses) may be deployed in the optical path between the liquid lens 318a and the TSFP 16, to provide correction for optical aberrations.

[0130] FIG. 19 illustrates another embodiment, similar to the embodiment illustrated in FIG. 18, but utilizing an Alvarez lens set 418a (instead of a liquid lens) deployed in a fixed (non-movable) location on the optical axis in the optical path between the inversion unit 60 and the TSFP 16. The refractive plates of the Alvarez lenses within the Alvarez lens set 418a are designated 420a and 422a The control system 20 is functionally associated with the lens 418a and is configured to actuate relative lateral displacement between the refractive plates 420a and 422a in the x and / or y directions to induce phase variations so as to automatically adjust focus of the telescope device. In the figure, the x direction is along the axis coming out of the plane of the paper, and the y direction is the vertical direction. In certain embodiments, the microcontroller of the control system may drive the actuator to act on one of the refractive plates 420a or 422a so as to move the refractive plates 420a or 422a. In other embodiments, the control system may include an actuator for each refractive plate so that the refractive plates are independently actuatable.

[0131] In certain embodiments, the actuation of the Alvarez lens set 418a is based on the fixed location of the TSFP 16. In other embodiments, actuation of the Alvarez lens set 418a is provided by manual actuation.

[0132] For the purposes of instantaneous and automatic focus, a single Alvarez lens set 418a may be deployed. However, in the illustrated embodiment a second Alvarez lens set 418b is also deployed, in another fixed location on the optical axis, for example in the optical path between the objective 14 and the inversion unit 60. The additional Alvarez lens set 418b can be used to alter the magnification of the telescope and / or to provide the telescope with zoom functionality. The refractive plates of the Alvarez lens set 418b are designated 420b and 422b. In certain embodiments, the control system may be functionally associated with the Alvarez lens set 418b and may be configured to actuate relative lateral displacement between the refractive plates 420b and 422b in the x and / or y directions. In other embodiments, actuation of the Alvarez lens set 418b is provided by manual actuation.

[0133] In certain embodiments, such as the embodiment illustrated in FIG. 19, optical aberration corrective lens (or set of lenses) 320 may be deployed, in the same fashion as described above with reference to FIG. 18.

[0134] Alvarez lens sets provide the same advantages as liquid lenses in that they are compact, are optimally placed in close proximity to the inversion unit 60 (at a distance less than the physical distance between the light entrance and light exit surfaces of the inversion unit), and provide fast focus adjustment. Alvarez lens sets provide an additional advantage in that they are effective for correcting diopter and astigmatic vision in eyes. Typically, users that have diopter or astigmatism wear eyeglasses (diopter and / or astigmatism corrective lenses) while viewing objects through telescopic devices (telescopes, binoculars, etc.). This compels an increase of the eye relief distance between the user’s eye and the eyepiece of the telescope. Employing Alvarez lens sets in the telescope devices of the embodiments described herein enables users that typically wear eyeglasses to correct for diopter and / or astigmatism, to use the telescope devices (whether in a monocular configuration or binocular configuration) without wearing their eyeglasses. This integration of Alvarez lens sets in the telescope device has the benefit of reducing the eye relief of the telescope device, which contributes to the compactness of the telescope device in comparison to conventional telescope devices that lack diopter and / or astigmatism correction. FIG. 23 shows an example of an eyepiece having a 70° apparent field of view and an exit pupil diameter of 4 mm. Ray tracing in the figure shows rays that would otherwise reach the eye from the eyepiece at an eye relief of 18 mm now reaching the eye at an eye relief of 11 mm, which effectively enables reduction of the diameter of the eye piece lens. In contrast, conventional telescopes (i.e., without Alvarez lens sets) have a higher eye relief (e.g., 18 mm) for the same apparent field of view (e.g., between 60° and 75°).

[0135] Turning now to FIG. 20, there is illustrated a telescope device having instantaneous and automatic focusing according to another embodiment of the present invention. Here, instantaneous and automatic focusing of the telescope device is performed using a detector 114 in combination with IFU 18 that is implemented as a liquid lens and / or an Alvarez lens set. The detector 114 is deployed to receive light from a lens 112, that is deployed in association with a surface 104 of prism 100 that is attached to the prism 70 of the inversion unit 60 (similar to as in the embodiment of FIG. 12). The IFU 18 may be deployed on the optical axis in the optical path between the objective 14 and the inversion unit 60, or, in certain embodiments, may replace one of the lenses of the objective 14 (i.e., the IFU 18 may be part of the objective 14).

[0136] The traversal of light in the illustrated embodiment is similar to as described with reference to FIG. 12, with the exception that the present embodiment includes an IFU 18 upstream from the inversion unit 60. Accordingly, light that from the objective 14 passes through the IFU 18 and enters the prism 70 through surface 72 and is reflected at the surface 76 toward the prism 100, in particular toward the surface 74 (and toward the beamsplitter 120). A part of the beam of light reflected at the surface 76 is transmitted by the beamsplitter 120, passes through the prism 100 (enters the prism 100 through the surface 102 and exits the prism 100 through the surface 104, which is typically in a direction normal to the surface 104), whereupon the light reaches and passes through the lens 112, which directs the light to the detector 114, which generates electronic signals in response to sensing / detecting the received light (and which may also form an image from the received light). Another part of the light reflected at the surface 76 is reflected by the beamsplitter 120 back toward the air gap 90 (typically normal to the surface 76), exits the first prism 70 through the surface 76 and enters the second prism 80 through the surface 86. The light then traverses through the second prism 80, undergoing total internal reflections from the various surfaces 82, 84, 86 of the prism 80, which as shown by the ray tracing in the figure may be multiple reflections from said surfaces, before ultimately exiting the prism 80 (and hence the inversion unit 60) through the surface 82 (similar to previously described). The light that exits from the inversion unit 60 then passes through the eyepiece 12, where it is viewed by the eye 1.

[0137] The processing unit 50 is electronically associated with the detector 114, and receives the generated electronic signals from the detector 114. The processing unit 50 may then process the received electronic signals, for example by executing one or more autofocus algorithms using the received signals as input, to generate instantaneous and autofocus data. The processing unit 50 may provide the autofocus data to the control system 20, which may then actuate the IFU 18 to adjust the focus of the lens 18 based on the autofocus data (and hence based on the electronic signals). This cycle may be repeated so that the light that passes through the now focused lens 18 is transmitted back to the processing unit 50 and to the eyepiece 12 and the viewer. The result of this process is that the viewer automatically and continuously receives and sees a sharp image.

[0138] The embodiment illustrated in FIG. 20 employs instantaneous and automatic focusing techniques on the basis of integration of the lens 112 and detector 114 via the additional prism 100 cemented to the inversion unit 60. An alternative embodiment, that foregoes the prism 100, is illustrated in FIG. 21. Here, a detector 32, which may be a matrix detector, is deployed at the edge of the field of view of the TSFP 16 (similar to as described with reference to FIG. 8). In certain embodiments, the detector 32 may be cemented to the rearmost surface of the eyepiece 12 (i.e., the surface of the last lens of the eyepiece 12 that is closest surface of the eyepiece 12 to the inversion unit 60). A group lens 140 may be deployed on the optical axis in the optical path between the inversion unit 60 and the eyepiece 12 such that the TSFP 16 is located between the eyepiece 12 and the field lens 140. The field lens 140 may be used to change the size of the image at the TSFP 16 (and hence at the detector 32), thus counteracting effects of field curvature. The IFU 18, which in the illustrated embodiment is a liquid lens (but may be an Alvarez lens set), is deployed between the inversion unit 60 and the objective 14 (or may be part of the objective 14, together with aberration corrective lens 322).

[0139] The beam of light from the objective 14 passes through the IFU 18 and traverses through the inversion unit 60 (as previously described), and then passes through the field lens 140 and to the eyepiece 12. Some of the beam of light from the lens 140 is detected by the detector 32, which generates electronic signals in response to sensing / detecting the received beam of light. The processing unit 50 is electronically associated with the detector 32, and receives the generated electronic signals from the detector 32. The processing unit 50 may then process the received electronic signals, for example by executing one or more autofocus algorithms using the received signals as input, to generate autofocus data. The processing unit 50 may provide the autofocus data to the control system 20, which may then actuate the IFU 18 to adjust the focus of the lens 18 based on the autofocus data (and hence based on the electronic signals). This cycle may be repeated so that the beam of light that passes through the now focused lens 18 is transmitted back to the processing unit 50 and to the eyepiece 12 and the viewer.

[0140] FIG. 22 shows another embodiment that employs instantaneous and automatic focusing techniques on the basis of a detector 32 that senses / detects at least some of the beam of light from the objective. It is noted that in FIG. 22, the inversion 60 unit is shown unfolded for ease of presentation. In this embodiment, a beamsplitter 150 is deployed between the inversion unit 60 and the TSFP 16 (intermediate focal plane) so as to direct part of the beam of light toward the detector 32 and part of the beam of light toward the eyepiece 12. The detector 32 is deployed in a configuration that is parallel to the optical axis, and the beamsplitter 150 may be deployed at a 45° relative to the optical axis (and relative to the TSFP 16). The beamsplitter 150 and the detector 32 may be deployed so that the distance from the TSFP 16 to the beamsplitter 150 and the distance from the detector 32 to the beamsplitter 150 are equal. In the illustrated configuration, a beam of light from the objective 14 passes through the IFU 18 (which may be a liquid lens and / or an Alvarez lens set) and traverses through the inversion unit 60 (as previously described), and then reaches the beamsplitter 150. Part of the beam of light from the inversion unit 60 is reflected by the beamsplitter 150 toward the detector 32, which generates electronic signals in response to sensing / detecting the received beam of light. Another part of the beam of light from the inversion unit 60 is transmitted by the beamsplitter 150 toward the eyepiece 12 and to the viewer’s eye. The lens control unit 20 may actuate the IFU 18 to adjust the focus of the IFU 18 based on the data / information received from the processing unit 50, similar to as described above.

[0141] The present disclosure has presented various telescope devices according to various nonlimiting example embodiments. These embodiments have featured, in various combinations and sub-combination, certain features according to certain aspects of the disclosure. It will be appreciated that other combinations and sub-combinations, besides those that have been explicitly presented herein for example purposes, are contemplated herein and fall within the scope of the present disclosure. Some of the features of the embodiments of the present disclosure and their various aspects will now be reiterated herein below.

[0142] In certain embodiments, a telescope device is provided in which the TSFP is coalesced with the image plane of the objective via an electro-optical and / or electro-optical-mechanical arrangement (IFU actuated by a control system) that automatically and repeatedly moves an IFU along the optical axis for instantaneous and automatic focusing. In certain embodiments, a camera system is deployed relative to an additional prism cemented to a prism-based inversion unit, whereby the optical axis of a lens of the camera system is normal to the light-exit surface of the additional prism. In such embodiments, there is an identity between the magnified field view in the camera and the magnified field of view as seen by the viewer through the eyepiece. Furthermore, such embodiments enable integration of one or more cameras that are sensitive to different spectral ranges (e.g., visible range, NIR, SWIR, MIR, LIR, etc.) as needed for various applications. In certain embodiments a digital microprojector arrangement can be integrated (instead of or in addition to the camera system) by deploying the digital projector in association with the additional prism so that the microprojector projects a beam of light corresponding to an image to the TSFP so that the viewer sees the projected image via the eyepiece (overlaid on the magnified real scene). In certain embodiments, a compact monocular or binocular configuration with reduced the eye relief is achieved by integrating an Alvarez lens set with the optical components of the telescope, which serves as a substitute for eyeglasses to correct diopter and / or astigmatism. In certain embodiments, one or more Alvarez lens sets and / or one or more liquid lenses (or a combination thereof) is deployed in the optical path to enable instantaneous and automatic or manual focusing and real-time depth of field auto-correction. In certain embodiments, a camera system forms images and / or generates electronic signals from a beam of light received through the one or more Alvarez lens set and / or one or more liquid lens, and these images and / or electronic signals are utilized by processing devices and / or control systems to actuate the Alvarez lens set and / or one or more liquid lens for instantaneous and automatic focusing operation. In certain embodiments, manual focusing is provided by one or more Alvarez lens set and / or one or more liquid lens. In certain embodiments, one or more Alavarez lens and / or one or more liquid lens provide zoom lens capability. In certain embodiments, one or more of the aforementioned embodiments is integrated in an AR and / or VR headset.

[0143] As mentioned, the features of the embodiments disclosed herein may be combined in various ways besides the explicit example combinations and sub-combinations described herein. For example, various embodiments have been presented herein that include an inversion unit with focusing optics and instantaneous and automatic focusing capability, but other embodiments are contemplated herein in which conventional focusing is employed in combination with inversion units having additional prisms cemented thereto. In another example, various embodiments have been presented herein that include a prism-based inversion unit and instantaneous and automatic focusing optics implemented as one or more liquid lens and / or one or more Alvarez lens set, but other embodiments are contemplated herein in which liquid lenses and / or Alvarez lens sets are employed in a telescope device without such a prism-based inversion unit.

[0144] It will also be appreciated that although only some of the illustrated embodiments show processing and control components in the form of, for example, a control system 20, a distance determining unit 30, and a processing unit 50 that may be interconnected (directly or indirectly) with each other and that may be connected (directly or indirectly) with one or more of sensor(s) / detector(s), one or more IFU (which in certain implementations may be liquid lenses and / or Alvarez lens sets), etc., the other embodiments illustrated in the drawings and described with reference thereto may include one or more of such processing and control components.

[0145] Various embodiments described herein include a prism-based inversion unit having an additional prism cemented thereto (see, for example, FIG. 10, showing inversion unit 60 and additional prism 100). The following is a brief discussion of some observations on the implementation details for such embodiments. First, in implementations in which the inversion unit is a Schmidt-Pechan prism (i.e., where the prism 70 is implemented as a Bauernfeind prism and the prism 80 is implemented as a Schimdt prism), the Bauernfeind prism 70 should be placed close to the objective 14, preferably so that the distance from the surface 72 to the objective 14 is in the range between 2 and 20 mm (however, the precise value of the distance may change depending on the particular application and configuration of the telescope). Second, the surface of the inversion unit prism 74 to which the added prism 100 is cemented does not support total internal reflection. Third, in embodiments in which additional prism 100 is cemented to the inversion unit 60, a beamsplitter is provided at the interface between the cemented surfaces of the two prisms 70 and 100. This beamsplitter preferably has a high reflection to transmission ratio, typically on the order of 98% reflection to 2% transmission. Fourth, the surface of the inversion unit 60 to which the additional prism 100 is cemented is not the light-entering surface 72 of the inversion unit 60 nor the light-exiting surface 82 of the inversion unit 60. Fifth, the optical axis is normal to the light-exit / light-entrance surface of the added prism 100 (e.g., surface 104 in FIGS. 10 and 12) with which additional integrated components are associated (e.g., lens 112, detector 114, lens 132, microprojector 130, etc.). The weight of the added prism 100 is lighter by some 40% from the weight of the prism 70 to which it is attached, and the compact volume of the prism 100 is lower by some 40% from the prism 70 to which it is attached. This specification of weight and volume is entwined with the second through fifth observations discussed above.

[0146] The telescope devices according to the embodiments of the present disclosure can be integrated as part of various optical products and systems, in monocular configurations and binocular configurations, including, but not limited to, hand-held binoculars, tripod mounted binoculars, surgical loups, hand-held monocular devices, tripod mounted devices, spotting scopes, optical sights, AR and / or VR headsets, etc.

[0147] Although the telescope devices discussed herein have been illustrated and described in the context of implementation according to a Keplerian configuration, implementation according to non-Keplerian configurations are contemplated herein and fall within the scope of the present disclosure. In general, the embodiments according to the present disclosure can be extended to any telescope device that includes an eyepiece for human viewing and in which there is an image that appears on rearmost focal plane before the eyepiece. The descriptions of the various embodiments of the present disclosure have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

[0148] As used herein, the singular form, “a”, “an” and “the” include plural references unless the context clearly dictates otherwise.

[0149] The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and / or to exclude the incorporation of features from other embodiments.

[0150] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0151] To the extent that the appended claims have been drafted without multiple dependencies, this has been done only to accommodate formal requirements in jurisdictions which do not allow such multiple dependencies. It should be noted that all possible combinations of features which would be implied by rendering the claims multiply dependent are explicitly envisaged and should be considered part of the disclosure.

[0152] Although the disclosure has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A telescope device, comprising: an eyepiece having one or more lenses; an objective having one or more lenses, the objective and the eyepiece defining an optical axis of the telescope device; an internal focusing unit (IFU) having at least one lens located between the objective and a transparent sensitive focusing plane (TSFP), the TSFP positioned at a fixed location on the optical axis between the eyepiece and the objective, wherein the fixed location is at a pre-assigned focal plane of the objective; and a control system functionally associated with the IFU and configured to actuate the IFU to instantaneously and automatically adjust focus of the telescope device based at least in part on the fixed location of the TSFP.

2. The telescope device of claim 1, wherein the control system is configured to coalesce an image plane of the objective with the TFSP.

3. The telescope device of claim 1, further comprising: a distance determining unit associated with the control system and configured to determine a distance from the telescope device to an object viewed through the telescope device, and wherein the control system is further configured to actuate the IFU based on the distance determined by the determining measuring unit.

4. The telescope device of claim 3, wherein the distance determining unit includes a time- of-flight sensor.

5. The telescope device of claim 1 , further comprising: a miniature camera system having at least one camera lens adjacent to a front end of the objective and having an optical path that is parallel to the optical path of the telescope device, wherein the camera lens is moveable along an optical axis of the miniature camera system so as to assume a plurality of positions along the optical axis of the miniature camera system, and wherein the control system is further configured to actuate the IFU based on sharpness or blurriness of an object imaged by the miniature camera system at the plurality of positions.

6. The telescope device of claim 1, further comprising: a detector deployed at an edge of a field of view of the TSFP, the detector electrically associated with the control system and configured to sense at least one of sharpness or blurriness of an image at the TSFP, and wherein the control system is configured to actuate the IFU based on signals indicative of the sharpness or blurriness sensed by the detector.

7. The telescope device of claim 1, wherein the IFU is moveable along the optical axis, and wherein the control system is configured to actuate the IFU to move along the optical axis relative to the TSFP to a focusing position.

8. The telescope device of claim 1, wherein the IFU includes at least one of a liquid lens or an Alvarez lens set.

9. The telescope device of claim 1, further comprising: an optical inversion unit formed from a pair of prisms, the optical inversion unit located between the objective and the IFU.

10. The telescope device of claim 9, further comprising: an additional prism cemented to one of the prisms of the pair of prisms, wherein the optical inversion unit and the additional prism form a prism assembly that provides: i) an optical path from the objective to the eyepiece, and ii) at least one of an optical path from the objective to a camera associated with a surface of the additional prism, or an optical path from a microprojector arrangement associated with a surface of the additional prism to the eyepiece.

11. The telescope of claim 9, further comprising: an additional prism cemented to one of the prisms of the pair of prisms; a lens associated with a surface of the additional prism; a detector; and a dichroic mirror aligned with the TSFP and configured to reflect light in a particular wavelength range and transmit light outside of the particular wavelength range, wherein the dichroic mirror, the optical inversion unit, the additional prism, the lens, and the detector are configured such that part of light in the particular wavelength range that exits from the objective traverses through the optical inversion unit toward the dichroic mirror, is reflected by the dichroic mirror back toward the optical inversion unit, traverses through the optical inversion unit toward the additional prism, and passes through the lens so as to form an image on the detector.

12. The telescope device of claim 11, wherein the control system is configured to actuate the IFU based on the image formed on the detector.

13. The telescope device of claim 9, further comprising: an additional prism cemented to one of the prisms of the pair of prisms; a beamsplitter at an interface between the additional prism and the one of the prisms of the pair of prisms; a lens associated with a surface of the additional prism; and a detector, wherein the optical inversion unit, the additional prism, the lens, and the detector are configured such that light that exits from the objective is reflected at an interface between the pair of prisms toward the additional prism, a part of the reflected light is transmitted by the beamsplitter so as to pass through the additional prism and then through the lens so as to form an image on the detector, and a part of thereflected light is reflected by the beamsplitter so as to traverse through the optical inversion unit toward the eyepiece.

14. The telescope device of claim 13, wherein the control system is configured to actuate the IFU based on the image formed on the detector.

15. The telescope device of claim 9, further comprising: an additional prism cemented to one of the prisms of the pair of prisms; and a microprojector arrangement including a projector lens associated with a surface of the additional prism and a microprojector associated with the projector lens, the microprojector arrangement configured to project light corresponding to an image, wherein the optical inversion unit, the additional prism, and the microprojector arrangement are configured such that light projected by the microprojector arrangement passes through the additional prism and traverses through the optical inversion unit toward the eyepiece, and wherein the optical inversion unit is configured such that light that exits from the objective traverses through the optical inversion unit toward the eyepiece.

16. The telescope device of claim 1, wherein a surface of the objective that is closest to the TSFP is coated with a coating that reflects light in a particular wavelength range, the telescope device further comprising: a dichroic mirror obliquely inclined relative to the TSFP and positioned so that centers of the dichroic mirror and TSFP overlap, the dichroic mirror configured to reflect light in the particular wavelength range and transmit light outside of the particular wavelength range; at least one converging lens; and a detector, wherein the dichroic mirror, the at least one converging lens, and the detector are configured such that part of light in the particular wavelength range that exits from the objective is reflected by the dichroic mirror back toward the surface of the objective, is reflected by the surface of the objective back toward the dichroic mirror, is reflected by the dichroic mirror toward the at least one converging lens, and passes through the at least one converging lens so as to form an image on the detector.

17. The telescope device of claim 16, wherein the control system is configured to actuate the IFU based on the image formed on the detector.

18. The telescope device of claim 1, further comprising: a manually adjustable lens located between the objective and the IFU.TA19. A telescope device, comprising: an eyepiece having one or more lenses; an objective having one or more lenses; and a prism assembly including: an optical inversion unit located between the eyepiece and the objective, the optical inversion unit formed from a pair of prisms, and an additional prism cemented to one of the prisms of the pair of prisms, wherein the prism assembly provides: i) an optical path from the objective to the eyepiece, and ii) at least one of an optical path from the objective to a camera associated with a surface of the additional prism, or an optical path from a microprojector arrangement associated with a surface of the additional prism to the eyepiece.

20. A telescope device, comprising: an eyepiece having one or more lenses; an objective having one or more lenses; a prism assembly including: an optical inversion unit located between the eyepiece and the objective, the optical inversion unit formed from a pair of prisms, and an additional prism cemented to one of the prisms of the pair of prisms; and a camera associated with a surface of the additional prism, wherein the prism assembly provides a first optical path from the objective to the eyepiece and a second optical path from the objective to the camera.

21. A telescope device, comprising: an eyepiece having one or more lenses; an objective having one or more lenses; a prism assembly including: an optical inversion unit located between the eyepiece and the objective, the optical inversion unit formed from a pair of prisms, and an additional prism cemented to one of the prisms of the pair of prisms; and a microprojector arrangement associated with a surface of the additional prism, wherein the prism assembly provides a first optical path from the objective to the eyepiece and a second optical path from the microprojector arrangement to the eyepiece.

22. A telescope device, comprising: an eyepiece having one or more lenses; an objective having one or more lenses, the eyepiece and the objective defining an optical axis of the telescope device; andan internal focusing unit (IFU) having at least one lens on the optical axis in the optical path between the eyepiece and at least one lens of the objective, the IFU including at least one of a liquid lens or an Alvarez lens set and configured to adjust focus of the telescope device.

23. The telescope device of claim 22, wherein the IFU is part of the objective.

Images