Patent Description:
Direct view optical weapon sights such as a rifle scope typically have optics with a fixed reticle for viewing and acquiring targets. <NPL>) discloses helmet mounted display sighting system. The system comprises an LED backlight behind the back side of an LCD, and two lenses on the opposite side of the LCD for directing images from the LCD to a combiner for viewing by the user. The document discloses an array of LEDs positioned side by side that are behind and spaced apart from a lens array. A planar diffractive element is positioned between the lens array and an LCD panel. The luminance from the LED array must then pass through the lens array, a planar diffractive element, and three gaps before reaching and illuminating the LCD panel. International Publication Number <CIT> discloses a display for head mounting having a light source, a spaced apart collimator lens adjacent to one side of a beam splitter and a display on another side of the beam splitter. US patent publication no <CIT> discloses a rifle sight with a display control unit, a direct view optics along a longitudinal axis with a display unit and a camera positioned on opposite lateral sides of a partially reflective lens. The display unit can include an LED and an LCD for generating images for superimposed viewing. The webpage "<NPL>] describes luminance as being a photometric measure of the luminous intensity per unit area of light travelling in a given direction. The webpage provides a mathematical definition of luminance and describes how, for real, passive optical systems, the output luminance is at most equal to the input. German patent publication <CIT> describes a head-up display with an image generation device (LCD) for generating an image and an optical system (AE) for projecting the image into a windshield (WS) of a vehicle. A light system illuminates the image generation device (LCD), the light system comprising at least one light source (D), which is followed by a light mixing geometry (LM), having reflective boundary surfaces on the inside in order to mix the light from the plurality of light sources (D).

The present invention can provide active display capabilities within a real-world viewer. According to a first aspect, there is provided a real-world viewer according to claim <NUM>.

In particular embodiments, the viewer can be at least one of a weapon sight, an add-on accessory to a weapon sight, a rifle sight, an add-on accessory to a rifle sight, a surveillance system, an add-on accessory to a surveillance system, a fire-control system, an add-on accessory to a fire-control system, a laser target locator and designator, an add-on accessory to laser target locator and designator, a head or helmet mounted display, an add-on accessory to a head or helmet mounted display, a range finder or an add-on accessory to a range finder. The viewing optics can be positioned along a longitudinal viewing optical axis. The display optical axis of the active display overlay unit can be at an angle to the viewing optical axis of the viewing optics. The active display overlay unit can include a lens arrangement for concentrating the LED illumination onto the active transmissive display. The lens arrangement can include an integrated lens integrated into the LED backlight and a condenser lens positioned between the integrated lens and the active transmissive display. The active display overlay unit can be capable of providing monochrome luminance of at least <NUM> cd/m<NUM> (<NUM> fL) to the ocular of the host system with the luminance to power cd/m<NUM>:mW ratio of at least <NUM>:<NUM> (fL:mW ratio of at least <NUM>:<NUM>) or greater. Electronics can be included for controlling the active display. The active display can provide images for at least one of an active target reticle, range and wind information, GPS and compass information, target ID, and/or external sensor information and/or video. A housing can be included for containing the viewing optics and the active display overlay unit. The field of view can include target or situational awareness elements therein. The active overlay display unit can be configured to control brightness to allow for viewing under ambient conditions ranging from full sunlight to overcast starlight. The active overlay display unit can be capable of outputting a specific wavelength of imagery and dimming for viewing the real-world and active overlay display unit images using an image intensifier night vision device or thermal imaging device. The active overlay display unit can provide at least one of a monochrome, multi-color and/or full color overlaid image. The active overlay display unit can provide at least one of a bi-level and/or full gray scale overlay image. Mechanical and electrical boresight capabilities can be included to the real-world viewing optical axis. Means can be included to package the active display overlay unit as an integral part of the real-world viewer. The active display overlay unit can be an accessory add-on device to the real-world viewer.

The present invention can also provide a weapons sight including direct viewing optics positioned along a longitudinal viewing optical axis for viewing a field of view of the real-world. The active display overlay unit provides full-color luminance of at least <NUM> cd/m<NUM> (<NUM> fL) to the ocular of the host system with a luminance to power cd/m<NUM>:mW ratio of at least <NUM>:<NUM> (fL:mW ratio of at least <NUM>:<NUM>) greater.

The present invention can also provide a method of viewing with a real-world viewer. According to a second aspect, there is provided a method according to claim <NUM>.

In particular embodiments, the viewer can be employed as at least one of a weapon sight, an add-on accessory to a weapon sight, a rifle sight, an add-on accessory to a rifle sight, a surveillance system, an add-on accessory to a surveillance system, a fire-control system, an add-on accessory to a fire-control system, a laser target locator and designator, an add-on accessory to laser target locator and designator, a head or helmet mounted display, an add-on accessory to a head or helmet mounted display, a range finder, or an add-on accessory to a range finder. The viewing optics can be positioned along a longitudinal viewing optical axis. The display optical axis of the active display overlay unit can be positioned at an angle to the viewing optical axis of the viewing optics. The LED illumination can be concentrated onto the active display with a lens arrangement. The lens arrangement can be provided with an integrated lens integrated in the LED backlight and a condenser lens can be positioned between the integrated lens and the active transmissive display. Monochrome luminance can be provided from the active display overlay unit to the ocular of the host system of at least <NUM> cd/m<NUM> (<NUM> fL) with a luminance to power cd/m2:mW ratio of <NUM>:<NUM> (fL:mW ratio of <NUM>:<NUM>) or greater. The active display can be controlled with electronics. The active display can provide images for at least one of an active target reticle, range and wind information, GPS and compass information, target ID, and/or external sensor information. The viewing optics and the active display overlay unit can be contained within a housing. Target or situational awareness elements can be viewed in the field of view. The active display brightness can be controlled to allow for viewing under ambient conditions ranging from full sunlight to overcast starlight. A specific wavelength of imagery and dimming of the active overlay display unit can allow for viewing the real-world and active overlay display unit images using an image intensifier night vision device or thermal imaging device. At least one of a monochrome, multi-color and/or full color overlaid image can be provided. A bi-level and/or full gray scale overlay image can be provided. Mechanical and electrical boresight capabilities to the real-world viewing optical axis, can be provided. Means to package the active display overlay unit as integral part of the real world viewer can be provided. The active display overlay unit can be an accessory add-on device to the real-world viewer. The present invention can also provide a method of viewing with a weapons sight including viewing a field of the real-world with direct viewing optics positioned along a longitudinal viewing optical axis, and simultaneously viewing images generated by an active display overlay unit optically coupled to the viewing optical axis of the viewing optics. The images can be directed along the viewing optical axis of the viewing optics for simultaneous overlay viewing of images and the real-world scene as viewed in the field of view through the viewing optics. The active display overlay unit provides full-color luminance of at least <NUM> cd/m<NUM> (<NUM> fL) to the ocular of the host system with a luminance to power cd/m<NUM>:mW ratio of at least <NUM>:<NUM> (fL:mW ratio of at least <NUM>:<NUM>) or greater. The active display overlay unit includes an active transmissive display generating the images along a display optical axis, an LED backlight illuminating the active transmissive display with LED illumination and configured to provide a cone angle of about +/-<NUM>° or less from the active transmissive display.

The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.

Referring to <FIG>, viewer <NUM> can be a display or viewing apparatus, device, sight, or scope in the present invention, which can be for or on, or part of a weapon, gun, rifle, surveillance system, fire-control system, laser target locater, range finder, or as a add-on accessory thereto. Embodiments can be mounted on a weapon, or apparatus, or can be hand held or helmet mounted. In one embodiment, viewer <NUM> can be used as a weapon, rifle or gun sight or scope, and can include direct visual optics, or direct view or viewing optics <NUM>, positioned within a scope tube, assembly or optics housing <NUM> along viewing optical axis A, such as an inline longitudinal axis, for viewing real-world images <NUM> (<FIG>). The optics <NUM> can have a viewing input end <NUM>, and a viewing output end or eyepiece <NUM>, which can be aligned along viewing optical axis A, and can be inline. Objects or targets <NUM> can be directly viewed with viewer <NUM> by the eye <NUM> of the user through the viewing input end <NUM>, along the viewing direct view optics <NUM>, and out the viewing output end <NUM>. The viewing optics <NUM> can include an objective lens or lens assembly <NUM> at the viewing input end <NUM>. A first focal plane reticle <NUM> can be positioned and spaced rearwardly along the viewing optical axis A from the objective lens assembly <NUM>. A picture or image reversal lens assembly <NUM> can be positioned and spaced rearwardly along the viewing optical axis A from the first focal plane reticle <NUM>. The picture reversal assembly <NUM> can include two lenses 20a and 20b spaced apart from each other. An aperture in a second focal plane <NUM> can be positioned and spaced rearwardly along the viewing optical axis A from the picture reversal assembly <NUM>. An ocular lens assembly <NUM> can be positioned and spaced rearwardly along the viewing optical axis A from the aperture in the second focal plane <NUM>, at the eyepiece <NUM>. The ocular lens assembly can include two lenses 24a and 24b spaced apart from each other. Lenses 24a and 24b can include more than one lens element. In some embodiments, the viewing optical axis A and the direct viewing optics <NUM> can be folded.

An active display overlay unit <NUM> can be optically coupled to the viewing optical axis A of the direct viewing optics <NUM> for generating images (<NUM> (<FIG>) with an active display <NUM> and directing the images <NUM> along the optical axis A for simultaneous overlaid viewing of the generated images <NUM> and images <NUM> of the real-world scene, including targets <NUM>, when looking through the direct viewing optics <NUM> through eyepiece <NUM>. The active display overlay unit <NUM> can direct generated images <NUM> along a display optical axis B, which can be at any angle to viewing optical axis A, such as at a right angle. The images <NUM> can be redirected from the display optical axis B onto the viewing optical axis A with a beam combiner <NUM> for simultaneously superimposing or overlaying the images <NUM> onto the images <NUM> of the scene viewed by the viewer through the optics <NUM>. The active display overlay unit <NUM> includes a backlight/display device, apparatus, assembly, module or arrangement <NUM> for generating the images <NUM>, and a beam combiner <NUM> for combining the images <NUM> with the images <NUM> of the direct viewing optics <NUM>. The beam combiner <NUM> of the active display overlay unit <NUM> can be positioned on and optically coupled to viewing optical axis A, between lens assemblies <NUM> and <NUM>, such as between the aperture in the second focal plane <NUM> and the ocular lens assembly <NUM>. The active display <NUM> can generate images <NUM> that can include text, alpha-numerics, graphics, symbology and/or video imagery, icons, etc., including active target reticles, range measurements and wind information, GPS and compass information, target finding, recognition and identification (ID) information, and/or external sensor information (sensor video and/or graphics), or images for situational awareness, for viewing through the eyepiece <NUM> along with the images <NUM> of the view seen through optics <NUM>. The direct viewing optics <NUM> can include or maintain the existing reticle and bore sight, and retain high resolution.

The beam combiner <NUM> can provide the optical function that combines the direct viewing optics <NUM> see through path along viewing optical axis A, with the display overlay path along display optical axis B. The center line C of the beam combiner <NUM> can be offset from the display optical axis B, by a small amount. In some embodiments, the center line C can be aligned with axis B. The beam combiner <NUM> can have a partially reflecting coating or surface 36c that reflects and redirects the output or at least a portion of the active display <NUM> output from axis B onto axis A to the viewer's eye <NUM> at eyepiece <NUM> while still providing good transmissive see-through for the direct viewing optics <NUM> path. The beam combiner <NUM> can be a beam splitter cube made of optical material, such as optical glass or plastic materials with a partially reflective coating 36c. The coating 36c can be a uniform and neutral color reflective coating, or can be tailored with polarizing, spectrally selective or patterned coatings to optimize both the transmission and reflection properties in the eyepiece <NUM>. The polarization and/or color of the coating 36c can be matched to the display <NUM>; This can optimize reflectance and efficiency of the display optical path with minimal impact to the direct viewing optics <NUM> transmission path. Although the beam combiner <NUM> is shown as a cube, in some embodiments, the beam combiner <NUM> can have different optical path lengths for the active display overlay unit <NUM> or display <NUM> along display optical axis B, and the direct viewing optics <NUM> along viewing optical axis A. In some embodiments, the beam combiner <NUM> can be of a plate form, where a thin reflective/transmissive plate can be inserted in the direct viewing optics <NUM> path across the optical axes A and B.

Referring to <FIG> and <FIG>, the active display <NUM> can be a reflective, transmissive or an emissive micro-display, and can be a microdisplay such as a Kopin Corporation, Taunton, MA, transmissive active matrix LCD display (AMLCD). The active display <NUM> can be monochrome or can provide full color, and in some embodiments, can provide multi-color. In other embodiments, other suitable designs or types of displays can be employed. The active display <NUM> can be driven by electronics <NUM>, via line <NUM> (<FIG>). The electronics <NUM> can include the ability to generate display symbols, format output for the display, and include battery information, batteries, or connect to batteries, power conditioning circuitry, video interface, serial interface and control features. Other features can be included for additional or different functionality of the active display overlay unit <NUM>. The electronics <NUM> can provide display functions, or can receive such functions from another device in communication therewith.

The active display <NUM> can be part of a backlight/display assembly, module or arrangement <NUM>, having a backlight assembly <NUM> including a backlight illumination or light source, device, apparatus or member <NUM>, such as an LED backlight for illuminating the active display <NUM> with light <NUM>. In some embodiments, the backlight source <NUM> can be a large area LED and can include a first or an integrated lens 42a, for collecting and directing generated light <NUM> to a second, illumination or condenser lens <NUM>, for collecting, concentrating and directing the light <NUM> onto active display <NUM>, along display optical axis B, with good spatial and angular uniformity. The illuminated images <NUM> from active display <NUM> are then directed to the beam combiner <NUM> for combining with images <NUM> seen through the direct viewing optics <NUM>, for viewing at eyepiece <NUM>. The backlight assembly <NUM>, active display <NUM>, and the active display overlay unit <NUM> are able to provide images <NUM> with sufficient high brightness luminance to be simultaneously viewed with a very high brightness real world view through optics <NUM>, while being at low power. The backlight <NUM> color can be selected to be any monochrome color, or can be white to support a full color microdisplay. Other backlight design elements can be included, such as other light sources, waveguides, diffusers, micro-optics, polarizers, birefringent components, optical coatings and reflectors for optimizing performance of the backlight <NUM>, and which are compatible with the overall size requirements of the active display overlay unit <NUM>, and the luminance, power and contrast needs.

When the viewer <NUM> is a weapon sight such as a gun or rifle sight or scope, the viewer <NUM> can still allow the existing features of the direct view optics sight to be provided such as target finding, target recognition, target identification, range measurement and targeting. The existing direct viewing optics <NUM> can maintain the existing reticle and boresight, and can retain the high resolution direct viewing optics <NUM> image. Additional capabilities provided by the active display overlay unit <NUM> can include an active target reticle, display of range and/or wind information, display GPS and/or compass information, display target identification (ID), and display an external sensor image overlayed with the direct viewing optics <NUM> (sensor video and/or graphics). Prior art direct viewing sights typically incorporated fixed or mechanically adjustable reticles or targeting references, while the active display overlay unit <NUM> can provide electrically dynamic information and targeting references which provides enhanced capability. Spectrally selective and polarized coatings 36c can be used to provide efficient see through directing viewing optics <NUM> with efficient reflectance for the active display overlay unit <NUM>.

<FIG> depicts an example of the view through an embodiment of viewer <NUM>, showing the viewed or image field <NUM> which includes real world images <NUM> seen through the direct viewing optics <NUM>, as well as overlayed images <NUM> from the active display overlay unit <NUM>. The direct viewing optics <NUM> can include an existing reticle or cross hair <NUM> visible in the image field <NUM>, which can be fixed or mechanically adjustable. The overlayed images <NUM> shown, include examples of compass information, an active target reticle, battery information, icons, text, and range information. It is understood that depending upon the embodiment or desired functionality, additional images can be overlayed to include further features, including those previously described. Also the active display overlay unit <NUM> can be controlled by electronics <NUM> to switch between different functions to show different images <NUM> or groupings of images <NUM> at a given moment in time.

In the embodiment seen in <FIG>, the optics housing <NUM> of the viewer <NUM> can include a mounting rail <NUM> for mounting to a desired weapon, equipment or device, and can have an adjustment mechanism <NUM> including an elevation adjustment drum for adjusting the elevational position of the optics <NUM>. A lateral adjustment mechanism <NUM> (<FIG>) similar to mechanism <NUM> is also typically provided for side-to-side adjustment. The adjustment mechanisms can be covered with a protection cap <NUM>.

Referring to <FIG>, in one embodiment, active display <NUM> can have a frame <NUM> and can be connected to a flexible or flex cable 46a that provides power and control signals to the display <NUM>. Active display <NUM> in one embodiment, can be a Kopin LV64OM Monochrome AMLCD with a resolution of <NUM> x <NUM> pixels, <NUM> x <NUM> pixel size, <NUM> x <NUM> image plane size, typical power of <NUM> milliwatts (mW), an integrated flex connector cable 46a, internal heaters for cold temperature operation, an operating temperature of -<NUM> to <NUM> and a storage temperature of -<NUM> to <NUM>. In other embodiments, active display <NUM> can have full color, multi-color, other resolutions, pixel sizes, dimensions and specifications, and other suitable displays or types of displays or designs can be used. Light shielding can be included in some embodiments.

<FIG> depicts an example of an embodiment of a viewer <NUM> including a <NUM> × crew served weapon sight with direct viewing optics <NUM>. The active display overlay unit <NUM> can include a plate beam combiner <NUM>, and backlight/display assembly <NUM> with high brightness such as seen in <FIG>. The backlight/display assembly <NUM> can have a <NUM> x <NUM> monochrome active display <NUM>, can have at least about <NUM>. cd/ m2 (<NUM> fL) or greater luminance at <NUM> milliwatts (mW), can have about <NUM>:<NUM> or greater contrast and about a <NUM>,<NUM>,<NUM>:<NUM> dimming range. A <NUM> cd/m<NUM> (<NUM> fL) or greater luminance at <NUM> mW provides a luminance to power cd/m2:mW ratio of <NUM>:<NUM> (fL:mW ratio of <NUM>:<NUM>) or greater. Some embodiments can have full color luminance. Such luminance provided to the viewing optical axis A can allow viewing of images <NUM> in the daytime. The content can include an overlay reticle system from active display overlay unit <NUM>, and can include a daytime and image intensifier tube (I<NUM>T) viewable overlay reticle/thermal system. The backlight/display assembly <NUM> can include a housing <NUM> for housing and positioning an LED light source <NUM>, a diffuser <NUM> and active display <NUM> along display optical axis B. The housing <NUM> can be formed by more than one component assembled together, such as housing portions 60a, 60b, 60c and 60d, which can be assembled together to house and hold display <NUM>, diffuser <NUM> and light source <NUM> in position. Portions or all of the housing <NUM> can be made of aluminum to act as a heat sink for light source <NUM>. Housing portion 60c can have outwardly angling reflecting or reflectorized surfaces <NUM> extending between light source <NUM> and diffuser <NUM>, for reflecting and directing light <NUM> to the diffuser <NUM>. The light source <NUM> in some embodiments can be a quad amber LED, and can be spaced or positioned apart from or behind the diffuser <NUM> by a distance d<NUM>, such as about <NUM>. The diffuser <NUM> can be spaced or positioned apart from or behind the active display <NUM> by a distance d<NUM>, such as about <NUM>. The reflecting surfaces <NUM> can collect and direct light <NUM> from light source <NUM> to increase the efficiency of the light delivery to active display <NUM>. The reflecting surfaces <NUM> can angle about <NUM>° relative to display optical axis B from a position slightly wider than the light source <NUM> to a position about the width or size of diffuser <NUM>. It is understood that the sizes, shapes, dimensions and specifications can be varied to suit different situations.

<FIG> depicts an example of an embodiment of a viewer <NUM> mounted to a weapon such as a sniper rifle, including a variable magnification sniper sight or scope as the direct viewing optics <NUM>, such as a <NUM> - <NUM> x <NUM> sniper sight. A view or image field <NUM> is also represented, showing real-world images <NUM> and an existing fixed reticle <NUM> seen through the direct viewing optics <NUM>, as well as overlayed images <NUM> from the active display overlay unit <NUM>, which can include an overlay reticle. A sniper sight, sighting device or apparatus <NUM> can also be mounted to the rifle <NUM> for measuring all relevant physical phenomena that can influence ballistic trajectory and calculate and display the offset aim point and confidence metric in the scope or direct viewing optics <NUM>. The sighting device <NUM> can provide the ability to see the aim point on the target in both day or night, and can enable rapid target identification, weapon alignment, and measurement of range to target and crosswind profile. The sighting device <NUM> can be in communication with the active display overlay unit <NUM> for displaying images <NUM> in the image field <NUM>, and can be mounted to the weapon <NUM> or can be separate. Some embodiments of sighting devices <NUM> can be positioned in front of the direct viewing optics <NUM>.

Referring to <FIG>, the embodiment of the active display overlay unit <NUM> in <FIG> can include a housing, housing portion, or cover <NUM> for housing and positioning the beam combiner <NUM> along viewing optical axis A, between lens assemblies <NUM> and <NUM>, and secured to housing portions <NUM> and <NUM>. The backlight/display assembly <NUM> can be positioned within housing <NUM> adjacent to or against one side of the beam combiner <NUM>, and the display optical axis B can be at a <NUM>° or right angle to viewing optical axis A. The display electronics <NUM> can be housed within housing <NUM> at a position spaced apart from another side of the beam combiner <NUM>. This can incorporate the active display overlay unit <NUM> within direct viewing optics <NUM> such as a rifle scope, while minimizing any increases in size of the scope.

Referring to <FIG> and <FIG>, the embodiment of the backlight/display assembly <NUM> in <FIG> can be generally rectangular in shape. Housing portions 60d and 60c can be secured to respective housing portions 60c and 60b, by insertion of locking protrusions <NUM> into recesses <NUM>. The active display <NUM> can be a <NUM> x <NUM> monochrome display and the light source <NUM> can be a large area LED with a first or integrated lens 42a. The integrated lens 42a can have a generally hemispherical shape with a generally spherical front face and can collect maximum available light generated from the light source <NUM> and direct the light <NUM> to a second, illumination, or condenser lens <NUM>, positioned between the light source <NUM> and the active display <NUM>, all along display optical axis B. The condenser lens <NUM> can have a generally flat rear face or surface facing integrated lens <NUM>, and a generally spherical front face with a larger radius than on the integrated lens 42a for concentrating light <NUM> received from integrated lens 42a onto active display <NUM> in an efficient manner. The first lens 42a is shaped to collect a maximum amount of light <NUM> available from light source <NUM>, and the second lens is shaped and positioned to collect and direct the received light <NUM> onto active display <NUM> in a manner that provides uniform maximum brightness across the active display <NUM>. The front face of the integrated lens 42a can be spaced from the rear face of condenser lens <NUM> by a distance d<NUM>, for example about <NUM>, and the front face of condenser lens <NUM> can be spaced from the rear face of active display <NUM> by a distance d<NUM>, for example about <NUM>. The light source <NUM> can be positioned within housing portion 60c, the condenser lens <NUM> can be positioned within housing portion 60b, and the active matrix <NUM> can be positioned within housing portion 60a, all secured along display optical axis B. This backlight/display assembly <NUM> with the two stage lens arrangement can have a very high brightness to power efficiency, with a monochrome luminance of at least <NUM> cd/m2 (<NUM> fL) or greater to the ocular of the host system at <NUM> mW, and can have about a <NUM>:<NUM> or greater contrast. A <NUM> cd/m2 (<NUM> fL) or greater luminance at <NUM> mW can provide a luminance to power cd/m2 :mW ratio of at least <NUM>:<NUM> (fL:mW ratio of at least <NUM>:<NUM>) or greater. Such luminance provided to the viewing optical axis A can allow the overlayed images <NUM> to be daytime viewable, while being power efficient.

<FIG> depicts an example of an embodiment of a viewer <NUM> attached to a weapon, gun or rifle <NUM>, in which the direct viewing optics <NUM> is a <NUM> x <NUM> ACOG sight (Advanced Combat Optical Gunsight) or scope, which can be fixed magnification. The viewer <NUM> can include the backlight/display assembly <NUM> seen in <FIG> and <FIG>, and can have a <NUM> x <NUM> monochrome active display <NUM>. The backlight/display assembly <NUM> can be part of an active display overlay unit <NUM> that can provide daytime viewable images <NUM> such as an overlay reticle system and can provide an image field such as shown and described for <FIG>. The backlight/display assembly <NUM> can provide a monochrome luminance of at least <NUM> cd/m<NUM> (<NUM> fL) or greater to the ocular of the host system at <NUM> mW, and can have about a <NUM>,<NUM>,<NUM>:<NUM> dimming range. A <NUM> cd/m2 (<NUM> fL) or greater luminance at <NUM> mW can provide a luminance to power cd/m2 : mW ratio of at least <NUM>:<NUM> (fL:mW ratio of at least <NUM>:<NUM>) or greater. Some embodiments can provide monochrome luminance at such levels to the eye.

Referring to <FIG>, the backlight/display assembly <NUM> and the beam combiner <NUM> of the active display overlay unit <NUM> of <FIG> can be horizontally aligned along display optical axis B at a right angle to viewing optical axis A. The beam combiner <NUM> can have a coating 36c with <NUM>/<NUM> non-polarizing coating, or implemented with a coating customized for red LED wavelength and s-polarization. The display electronics <NUM> can be positioned offset from and under the beam combiner <NUM> and backlight/display assembly <NUM>.

Referring to <FIG>, in some embodiments, the beam combiner <NUM> of the active display overlay unit of <FIG> can be cube shaped and formed of two optical members or elements 36a and 36b combined or bonded together. The coating 36c can be formed by coating one or both bonded hypotenuse surfaces with an optical thin film coating so that photopically weighted transmission (<NUM> to <NUM>) for non-polarized light is greater than <NUM>% for angles of incidence of <NUM>° +/- <NUM>°. Reflectance (<NUM> to <NUM>) for s-polarized light is greater than <NUM>% for angles of incidence of <NUM>° +/- <NUM>°. Anti-reflection coating can be applied to surfaces such that photopically weighted reflectance (<NUM> to <NUM>) for non-polarized light is less than <NUM>% for angles of incidence of <NUM>° +/- <NUM>°. Anti-reflection coating can be applied to surfaces such that photopically weighted reflectance (<NUM> to <NUM>) for non-polarized light is less than <NUM>% for angles of incidence of <NUM>° +/- <NUM>°. This can form a customized red s-polarized reflective coating for the beam combiner <NUM>. It is understood that different coatings can be applied to beam combiner <NUM> to meet the requirements of different embodiments in the present invention, shown and described.

Referring to <FIG>, the direct viewing optics <NUM>, such as in a weapon sight such as a rifle or gun sight or scope, can have well defined and limited angles of incidence (AOI) at the image plane, and can have small cone angles of illumination at the image plane less than about +/- <NUM>°, such as +/- <NUM>°. Embodiments of the active display overlay unit <NUM> can be configured to provide illumination that matches, or approximately or substantially matches the angles of incidence of the direct viewing optics <NUM> at the image plane to obtain optimum simultaneous viewing at the eyepiece <NUM> of images from both optical axes A and B, for images <NUM> viewed by the direct viewing optics <NUM>, and for images <NUM> generated by active display overlay unit <NUM>.

Referring to <FIG>, in one embodiment, the backlight/display assembly <NUM> for the direct viewing optics <NUM> of <FIG>, can have a light source <NUM>, such as an LED illuminating the active display <NUM>, which can be an LCD such as shown and described with respect to <FIG>. The backlight/display assembly <NUM> can be similar to that in <FIG>. The LED light source <NUM> can be positioned a distance d<NUM> from the active display <NUM>, and can directly illuminate the active display <NUM>, with light <NUM> to produce a very high luminance of the surface of the active display <NUM> to obtain a high luminance of images <NUM> in the eyepiece <NUM> of the direct viewing optics <NUM>, while matching, or approximately or substantially matching the images of incidence and cone angles at the image plane of the direct viewing optics <NUM>. The size and location of the light source <NUM> relative to the active display <NUM> can be selected to provide desired angles of incidence and cone angles of illumination of light <NUM> at the active display <NUM>. In direct illumination of active display <NUM> by light source <NUM>, the illumination or light <NUM> is under divergent conditions. In one embodiment, the light source <NUM> can be a large area LED with dimensions of about <NUM> x <NUM> at a distance d<NUM> of about <NUM> and provide about +/- <NUM>° of cone angle output from the image plane of the active display <NUM>. In another embodiment, the light source <NUM> can be a medium area LED of about <NUM> × <NUM> at a distance d<NUM> of about <NUM> and provide about +/- <NUM>° of cone angle output from the image plane of the active display <NUM>. In another embodiment, the light source <NUM> can be a small area LED of about. <NUM> at a distance d<NUM> of about <NUM>, and provide about +/- <NUM>° of cone angle output from the image plane of the active display <NUM>. As a result, cone angles of +/- <NUM>° or less can be achieved to match or substantially match, or approximately match the direct viewing optics <NUM>. The angles of incidence can be halfway between or bisect the cone angles as shown. In some embodiments, light source <NUM> can have an integrated lens 42a if desired.

Referring to <FIG>, in another embodiment, the backlight/display assembly <NUM> for the direct viewing optics <NUM> of <FIG> can have a light source <NUM>, such as an LED for illuminating the active display <NUM>, which can be an LCD such as shown and described with respect to <FIG>. A condenser or illumination lens <NUM> can be positioned between the light source <NUM> and the active display <NUM>, and can be spaced apart from the light source <NUM> by a distance d<NUM>, and the assembly can be similar to any of the backlight/display assemblies <NUM> shown in <FIG> and <FIG>. The lens <NUM> can be in front of and adjacent to or next to the active display <NUM> and receives light <NUM> from light source <NUM> and directs the light <NUM> onto the active display <NUM> in a manner to obtain a high luminance of images <NUM> in the eyepiece <NUM> of the direct viewing optics <NUM>, while matching, or approximately or substantially matching the angles of incidence and cone angles at the image plane of the direct viewing optics <NUM>. The size and location of the light source <NUM> relative to the active display <NUM> and the lens <NUM> can be selected to provide desired angles of incidence and cone angles of illumination or light <NUM> at the active display <NUM>. In one embodiment, the light source <NUM> can be a large area LED with dimensions of about <NUM> x <NUM> at a distance d<NUM> of about <NUM> and provide about a +/-<NUM>° of cone angle output from the image plane of the active display <NUM>. In another embodiment, the light source <NUM> can be a medium area LED of about <NUM> × <NUM> at a distance d<NUM> of about <NUM> and provide about a +/- <NUM>° of cone angle output from the image plane of the active display <NUM>. In another embodiment, the light source <NUM> can be a small area LED of about. <NUM> at a distance of about <NUM> and provide about a +/- <NUM>° of cone angle output from the image plane of the active display <NUM>. As a result, cone angles of +/- <NUM>° or less can be achieved to match, or approximately or substantially match the direct viewing optics <NUM>. The angles of incidence can be about halfway between or bisect the cone angles, as shown. The lens <NUM> and its design can allow angles of incidence of illumination at the active display to match, or approximately or substantially match viewing optics that are divergent or convergent independent of light source <NUM> distance. In some embodiments, the light source <NUM> can include an integrated lens 42a. The designs of the backlight/display assemblies <NUM> and active display overlay unit <NUM> shown and described can provide high luminance images <NUM> to be produced in a manner that can be seen simultaneously with images viewed with the direct viewing optics, even during the day.

The viewer <NUM> in the present invention, can have a variety of uses and embodiments, and can be a weapon sight, such as a rifle sight or scope, a sighting and surveillance system, a fire-control system, a laser target locator and designator, a range finder, a monocular or binocular viewing system (either hand-held or head/helmet mounted), or add-on accessory devices thereof, and the field of view can include target elements therein. The viewing optics can be positioned along a longitudinal viewing optical axis or folded such as in a periscope. The active display overlay unit can include a display element for generating the images, including text and symbology along a display optical axis. A beam combiner or other means to optically combine the images can be aligned with the display along the display optical axis, and positioned along the viewing optical axis of the viewing optics for directing the images from the display onto the viewing optical axis for combining with the field of view that is viewed by the viewing optics with those of the display in an overlaid manner. The display optical axis of the active display overlay unit can be at any angle to the viewing optical axis of the viewing optics, and can include right angles. The active display overlay unit can utilize a reflective display element, a transmissive display element or an emissive display element, which can be an active display. It can further include an LED backlight for illuminating a transmissive display or active display with LED illumination. A lens arrangement can focus or concentrate the LED illumination onto the transmissive display or active display and into the viewing area. Electronics can control the display, the display format and content as well as the relative position of imagery and symbology with respect to the viewing optical axis. The display can provide text, alpha-numerics, symbology and/or video imagery including an active target reticle, range and wind information, GPS and compass information, target ID, and/or external sensor information.

The display overlay unit can receive external information and display a weapon solution based upon a ballistic calculation and environmental conditions such as temperature, altitude, humidity, wind velocity, air density and earth rotation coupled with target and ballistics information such as range to target, wind profile to target, specific rifle bore, shot load, barrel length and target speed. The display overlay unit may contain an internal symbol set and position symbology according to external commands or receive display information and position externally. The display overlay unit can output or provide monochrome, multi-color and/or full color overlaid image content, can be bi-level and/or full gray-scale image capable and can provide a high brightness display with dimming capability to support a wide range of ambient viewing conditions ranging from full sunlight to overcast starlight. The display overlay unit provides at least one of full-color and monochrome luminance of at least about <NUM>. <NUM> cd/m2 (<NUM> fL) to the ocular of the host system with a luminance to power cd/m2:mW ratio of at least <NUM>:<NUM> (fL:mW ratio of at least about <NUM>:<NUM>) or greater, for example, full color luminance of at least about <NUM> cd/m2 (<NUM> fL) or greater at about <NUM> mW, or monochrome luminance of at least about <NUM> cd/m2 (<NUM> fL) or greater at about <NUM> mW. The dimming range and spectral content or specific wavelength of imagery of the display can be such that the display can be dimmed to a level allowing the user to view the overlaid image and real-world scene through the viewing optics with image intensifier (night vision goggle) based products or thermal imaging devices.

A housing can be included for containing the viewing optics and the display overlay unit. The complete unit can be mounted as an external accessory device which is then coupled to the real-world optical viewing device or integrated into a larger system such as a fire-control, target locator/designator or weapon sight system. The unit can be packaged as an integral part of the real-world viewing system. In some embodiments, the active overlay display function can be an add-on accessory device to the real-world viewing system. The accessory device can contain features both mechanically and electrically to boresight (align) the overlaid display from the display overlay unit to the optical axis of the real-world viewer.

While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made.

Claim 1:
A real-world viewer (<NUM>) comprising:
viewing optics (<NUM>) positioned along a viewing optical axis (A) for viewing a field of view of the real-world; and
an active display overlay unit (<NUM>) optically coupled to the viewing optical axis (A) of the viewing optics (<NUM>), for generating images (<NUM>) and directing the images (<NUM>) along the viewing optical axis (A) of the viewing optics (<NUM>) for simultaneous overlaid viewing of the images (<NUM>) and the real-world scene as viewed in the field of view through the viewing optics (<NUM>), the active display overlay unit (<NUM>) providing luminance of at least <NUM> cd/ m<NUM> (<NUM> fL) to the ocular (<NUM>) of the host system with a luminance to the ocular of the host system to power consumption cd/m<NUM>:mW ratio of at least <NUM>:<NUM> (fL:mW ratio of at least <NUM>:<NUM>) or greater, in which the active display overlay unit (<NUM>) comprises:
an active transmissive display (<NUM>) for generating the images (<NUM>) along a display optical axis (B);
an LED backlight (<NUM>) for illuminating the active transmissive display (<NUM>), wherein the LED backlight (<NUM>) provides a cone angle of illumination at the active transmissive display that substantially matches a viewing cone angle of the viewing optics (<NUM>), the cone angle being about +/- <NUM>° or less; and
a beam combiner (<NUM>) aligned with the active transmissive display (<NUM>) along the display optical axis (B), and positioned along the viewing optical axis (A) of the viewing optics (<NUM>) for directing the images (<NUM>) from the active transmissive display (<NUM>) onto the viewing optical axis (A) for combining with the field of view that is viewed by the viewing optics (<NUM>) in an overlaid manner.