FIELD OF THE INVENTION

[0001] The present invention relates to optical instruments and more particularly, to optical instruments for projecting synthetic data into vision instruments.

BACKGROUND OF THE INVENTION

[0001] Prior to describing the background of the invention, it may be helpful to set forth definitions of certain terms that will be used hereinafter.

[0002] The term "image forming device" or simply 'cutaway' as used herein is the interruption of a continuously filmed action by inserting a view of something else. It is usually, although not always, followed by a cut back to the first shot.

[0003] Optical instruments for human observers (referred herein as vision devices) require sometimes the ability to provide synthetic information to be overlaid upon the image of the scene. The synthetic information may include an aiming reticle, azimuth, landmarks, battery level and the like.

[0004] Currently, overlaying synthetic data on vision devices may be achieved by several techniques. In one known technique, the synthetic data is projected onto an eyepiece using appropriate optical techniques. In another technique, a pattern (e.g. a retical for aiming) is embedded on a transparent glass plate. Then, as the glass has the ability to be shifted by an adjusting mechanism, an image of the pattern is controlled by the observer.

[0005] All of the aforementioned techniques usually involve complicated optics (mainly lenses and mirrors) that are required for generating an accurate overlay of the synthetic data upon the formed image (taking into consideration optical effects such as aberrations). Theses complicated optical arrangement sometimes makes the introduction of synthetic data projection complicated and even impossible, wither because of lack of compactness, which is required for some devices, or prohibitively expensive.

[0006] It would be therefore advantageous to provide an optical instrument that facilitates the projection of synthetic data onto and image formed by optical vision devices for delivering the image of the scene with the synthetic data to the observer. BRIEF SUMMARY OF THE INVENTION

[0007] Embodiments of the present invention provide an optical instrument for projecting a synthetic image into an image forming device (IFD) contained within an optical vision instrument in which the image-forming device includes a concave image source located at an effective focal plane of an eyepiece. The optical instrument includes: a synthetic image source configured to project a synthetically generated image; a fiber bundle having a first end couplable to the synthetic image source and a second end at which fibers of the fiber bundle are arranged to define a concave surface having a similar radius as the radius of the concave image surface of the image-forming device; a dichroic beam splitter configured to only transfer light within a wavelength range of the image produced by the image-forming device; and a folding element for folding an image transmitted by the second end of the fiber bundle into the dichroic beam splitter for reflecting into the eyepiece.

[0008] Advantageously, embodiments of the present invention provide a compact and flexible optical arrangement that enable retrofitting it to existing optical devices without incurring high costs of replacing many components or the optical elements.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] For a better understanding of embodiments of the invention and to show how the same may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings in which like numerals designate corresponding elements or sections throughout.

[0010] In the accompanying drawings:

[0011] Figure 1 is a schematic diagram illustrating schematic optical instrument according to embodiments of the present invention;

[0012] Figure 2 is a diagram illustrating the fiber bundle in accordance with embodiments of the present invention;

[0013] Figure 3 is a diagram illustrating another aspect of the fiber bundle in accordance with embodiments of the present invention;

[0014] Figure 4 is an exploded view diagram illustrating the optical arrangement in accordance with embodiments of the present invention; and

[0015] Figure 5 is a diagram illustrating a plurality of optical devices in which the optical instruments according to some embodiments of the present invention has been installed. [0016] The drawings together with the following detailed description make apparent to those skilled in the art how the invention may be embodied in practice.

DETAILED DESCRIPTION OF THE INVENTION

[0017] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

[0018] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0019] Embodiments of the present invention provide an apparatus that enables projecting synthetic data in any currently available vision system. The suggested instrument is a compact optical module that includes a digital displaying unit, which is projected to the line of sight (LOS) of the system and can change the displayed formation without the need of any mechanical movements or any complicated manufacturing processes.

[0020] Advantageously, embodiments of the present invention include a minimal number of optical components and further its installation process in any existing vision instrument is straightforward and simple.

[0021] Advantageously, embodiments of the present invention are designed so that none of the physical components of the system, particularly the fiber bundle does not obscure the line of sight (LOS) within the optical device the system is embedded to. Thus, the observer has a direct view of the analog optics.

[0022] Consequently, the vision system enhanced by embodiments of the present invention has the ability to function as an analog imaging system in case of electronical failure. Moreover, effects that may occur due to the additive information (such as contrast attenuation, damaging the field of view, aberrations or image distortions) are negligible. [0023] Furthermore, embodiments of the present invention are installed instead of an existing eyepiece, and therefore, the optical instrument of embodiments of the present invention can be considered as an upgrade kit instead of a complete product.

[0024] Embodiments of the present invention provide an optical instrument, which includes an image-forming device located at an optical path of the optical instrument, wherein the image- forming device includes a concave image surface. The optical instrument may further include an eyepiece located along said optical path, wherein the concave image surface of the image- forming device is located at an effective focal plane of the eyepiece. The optical instrument may further include a synthetic image source configured to project a synthetically generated image. The optical instrument may further include a fiber bundle having a first end coupled to the synthetic image source and a second end at which fibers of the fiber bundle are arranged to define a concave surface having a similar radius as the radius of the concave image surface of the image-forming device.

[0025] A dichroic beam splitter is positioned along said optical path between the image-forming device and the eyepiece and configured to transfer light within a wavelength range of the image produced by the image-forming device. Optionally, and as needed, a rotatable folding element configured to fold an image transmitted by the second end of the fiber bundle into the dichroic beam splitter, wherein the dichroic beam splitter is configured to reflect the image folded by the folding element into the eyepiece.

[0026] In accordance with embodiments of the present invention the optical instrument includes at least one optical element located between the folding element and the dichroic beam splitter and configured to match a level of magnification of the image coming from the folding element and the image coming from the image-forming device.

[0027] Figure 1 is a schematic diagram illustrating the aforementioned apparatus in further details according to embodiments of the present invention. Optical vision device 100 has an image-forming device (IFD) 1 with a concave image plane (with radius R) which is placed in front of an objective lens 14, thereby generating in imaging of any long distanced object or scene. Placing a moveable eyepiece 8, where its focal distance (represented by f) is located on the curvy image plane of the IFD 1 implements a telescope in front of observer 11 with intensified light illumination. A fiber bundle 3 is coupled to the top of a micro organic light emitting diode (O-LED) display unit 2 or any other micro display that serves as an image source. The glass faceplate of the O-LED which is commonly used, is replaced with fiber bundle 3. [0028] In operation, the light emitted from each pixel of O-LED display unit 2 is transferred via fiber bundle 3. At the end of fiber bundle 3 an image surface of the transferred O-LED 2 is created, called O-LED Image Surface (OIS) 4. Its geometrical formation is a concave surface with the radius R, which is identical to the one given in the IFD image surface 1. By doing so, the use of any additional lenses or any support optics (in order to solve aberrations differences between the channels) is unnecessary, since there is exact matching between the IFD image surface 1 and the OIS 4.

[0029] Then, OIS 4 displayed on the top of the concave surface is scaled up by an imaging lens Li 5 (i.e. is single lens relay optics with magnification), where the distances di, d2 and the focal distance /; are determined according to the imaging condition and the magnification ratio as set forth in Equations 1 and 2 below.

[0030] wherein di is the distance between the OIS and the lens Li, tfe is the distance between the lens Li and each of which if the two curvy images (i.e. The Mid image 15 and the IFD image 1), and wherein M - represents the magnification of the Mid-image 15 over the OIS 4.

[0031] According to optics fundamentals, the OIS radius is not effected due to the imaging occurred by the lens Li 5, result in scaled up OIS 15 with identical curve radius 'R. The scaled up OIS, called mid image 15, is located (using a folding mirror 6) perpendicular to the observer's LOS 9. A long pass Dichroic mirror 7 is placed on the LOS 9 in front of the image-forming device 1, reflecting the mid image 15 (red light's wavelength is around 600-750 Nm) and transferring the image-forming device image 1 (green light' s wavelength is around 490-570 Nm) to the observer 11 (through eye piece lens). Consequently, the rays emit from IFD 13 are transferred with minimal attenuation (about 5-8% energy loss), where the rays emit from the OIS 13 are reflected with minimal energy loss (about 2-5% energy loss). The total distance between the eyepiece and the image plane of the IFD, denoted as f2 (taking into consideration diopter corrections Δ) is equal to the distance between the eyepiece and the mid image of the OIS 15.

[0032] Figure 2 demonstrates the ability to create a compact module, where fiber bundle 3 surrounds the eyepiece lens in its unique spiral like formation. As a result, this module can be mounted inside housing 17 of a typical Binocular vision google (e.g. PVS15) as shown in Figure 5.

[0033] In the following example, the lens Li 5 can be an aspherical lens that is mounted in front of the CIFB image surface magnifying its size in a ratio of 3-4, enables the O-led and the fiber optics bundle to be overlapped where the final image has a total size that can capture the diameter of the image-forming device image surface 1; the mid image is given beyond the FOV of the observer (i.e. beyond the circle is given by the image plane of the IFD), and therefore, no ghost image is emerged to the observer. In order to decrease the total length of the system, and to obtain eyepiece with a relatively short focal distance, Reverse telephoto arrangement is used for the eyepiece 8. The folding mirror 6 has two degrees of freedom (along two respective transversal axes) in order to provide the ability to locate the mid image in its appropriate position. The dichroic beam splitter has an ellipse formation, in order to minimize its volume in the arrangement.

[0034] In accordance with the embodiments of the present invention the fiber bundle circumvents the optical path of the objective lens. In some embodiments, the fiber bundle is flexible and is capable of circumventing the optical axis of the optical device as may be required to optically convey the synthetic image from the OLED onto the location where it is being projected into the beam splitter. This enables great flexibility and allows a compact design necessary for an effective retrofit.

[0035] In accordance with embodiments of the present invention, the synthetic image source comprises an organic light emitting diode (OLED) display.

[0036] Figure 3 is a diagram illustrating another aspect of the fiber bundle in accordance with embodiments of the present invention. O-LED display unit 2 is transferred via fiber bundle 3. At the end of fiber bundle 3 an image surface of the transferred O-LED 2 is created, called O-LED Image Surface (OIS) 4. The OIS 4 displayed on the top of the concave surface is scaled up by an imaging lens Li 5 scaling up mid image of the OIS 15 which in turn in reflected to mirror 6 onto long pass Dichroic mirror 7. This illustration further demonstrates the ability to create a compact module that injects the synthetic image onto the field of view of the observer and into the incoming image from a scene.

[0037] Figure 4 is an exploded view diagram illustrating the optical arrangement in accordance with embodiments of the present invention. The optical bundle 3 is sown with O-LED display unit 2 on one side and O-LED Image Surface (OIS) 4 on the other side and Dichroic mirror 7 nested within the bundle as the scaled up mid image is projected upon it. Further shown are the image forming device 1, which forms the image onto which the synthetic imaged from display 2 is to be fused with as will be shown to the observer, using eyepiece 8. Housing 16 illustrates the rigid constraints defining the limited space through which the optical bundle needs to maneuver while achieving its functionality of injecting the synthetic image into the image formed by the image forming device 1 without interfering without obscuring any part of the field of view of the observer using eyepiece 8.

[0038] Figure 5 is a diagram illustrating a plurality of optical devices in which the apparatus according to some embodiments of the present invention has been installed. Illustration (a) shows a three-dimensional model inside image-forming device housing 16. Illustration (b) shows a cross-section A-A at (a); Illustration (c) is a three-dimensional model without image-forming device housing; Illustration (d) is a three-dimensional model without IFD form another direction; and (e) Illustration shows a cross-section B-B at (c); and illustration (f) shows a non-limiting example of typical vision binocular google PVS15.

[0039] In accordance with embodiments of the present invention the optical instrument may include an electronic circuitry (not shown in the figures) comprising a computer processor and a memory for storing a computer readable code that, when executed on the computer processor, generates a synthetic image to be projected by the synthetic image source.

[0040] In a case that the fiber bundle is a non-coherent fiber bundle the computer processor is configured to adjust the synthetic image to be projected by the image source so as to overcome mis-orientation of pixels caused by the non-coherent fiber bundle.

[0041] In accordance with embodiments of the present invention the electronic circuitry that generates the synthetic image enables both the data displaying on the O-Led screen and gathering data from external devices (e.g. sensors). Since the power supply of the device is a battery, monitoring the power consumption of both the electronic and the image-forming device units is required. In order to support different electrical components, different voltage levels may be required, both positive and negative voltages that are supplied and monitored for power up, power down and sleep mode (low power consumption for long operation time).

[0042] In order to provide the user with the ability to be oriented with localization data such as Global Position System (GPS) and angular orientations (such as azimuth and elevation), appropriate information needs to be displays on screen. Real global orientation is carried out by collecting data from a nine degrees of freedom (DOF) sensor that include gyroscope accelerometer and magnetometer with high resolution along each axis, processing the data through a mathematical algorithm that calculates the sensor orientation relative the earth using 3 main angles, pitch roll and yaw. A self GPS location and an object location creates a virtual line that has a 3D vector (Xi, Yi, Zi to X ₂ , Y ₂ , ¾) that need to be added to the mathematical algorithm in order to display the target location once the device is facing its direction.

[0043] Advantageously and in line with other embodiments of the present invention, the electronic circuitry is designed to be small size with very low power components manufactured for battery operated products.

[0044] In the above description, an embodiment is an example or implementation of the inventions. The various appearances of "one embodiment," "an embodiment" or "some embodiments" do not necessarily all refer to the same embodiments.

[0045] Although various features of the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment.

[0046] Reference in the specification to "some embodiments", "an embodiment", "one embodiment" or "other embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the inventions.

[0047] It is to be understood that the phraseology and terminology employed herein is not to be construed as limiting and are for descriptive purpose only.

[0048] The principles and uses of the teachings of the present invention may be better understood with reference to the accompanying description, figures and examples.

[0049] It is to be understood that the details set forth herein do not construe a limitation to an application of the invention.

[0050] Furthermore, it is to be understood that the invention can be carried out or practiced in various ways and that the invention can be implemented in embodiments other than the ones outlined in the description above.

[0051] It is to be understood that the terms "including", "comprising", "consisting" and grammatical variants thereof do not preclude the addition of one or more components, features, steps, or integers or groups thereof and that the terms are to be construed as specifying components, features, steps or integers.

[0052] If the specification or claims refer to "an additional" element, that does not preclude there being more than one of the additional element. [0053] It is to be understood that where the claims or specification refer to "a" or "an" element, such reference should not be construed that there is only one of that element.

[0054] It is to be understood that where the specification states that a component, feature, structure, or characteristic "may", "might", "can" or "could" be included, that particular component, feature, structure, or characteristic is not required to be included.

[0055] The descriptions, examples, methods and materials presented in the claims and the specification are not to be construed as limiting but rather as illustrative only.

[0056] Meanings of technical and scientific terms used herein are to be commonly understood as by one of ordinary skill in the art to which the invention belongs, unless otherwise defined.

[0057] The present invention may be implemented in the testing or practice with methods and materials equivalent or similar to those described herein.

[0058] Any publications, including patents, patent applications and articles, referenced or mentioned in this specification are herein incorporated in their entirety into the specification, to the same extent as if each individual publication was specifically and individually indicated to be incorporated herein. In addition, citation or identification of any reference in the description of some embodiments of the invention shall not be construed as an admission that such reference is available as prior art to the present invention.

[0059] While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other possible variations, modifications, and applications are also within the scope of the invention.