Telescope bypass mirror mechanism with minimized stow volume

An optical system (e.g., a telescope) comprising an optical assembly that reflects and refracts light rays through a single window about an optical path to a detector. A field-of-view bypass assembly comprises a bypass mirror movably coupled with respect to the optical assembly. The bypass mirror is selectively translatable and tiltable between a bypass configuration and a retracted configuration. In the bypass configuration, the bypass mirror is disposed in and interrupts the primary optical path and oriented to define a secondary optical path to the detector. In the retracted configuration, the bypass mirror is both disposed out of the primary optical path and is properly shielded to prevent stray light reflections.

BACKGROUND

There are numerous applications for optical imaging systems that require a high sensitivity narrow field-of-view telescope for detection and discrimination purposes. It is also frequently desirable, however, to additionally capture a wide field-of-view in order to achieve greater situational awareness. Typically, switching between fields-of-view involves the use of moving parts, such as mounts, laterally movable lenses (to provide “zoom”) or other movable optical components, such as a field-of-view switch.

DETAILED DESCRIPTION

In one example, there is provided an optical system that can be part of a reflective, high-magnification telescope, which in turn can be party of a turreted sensor system. The telescope, or optical system thereof, can direct collimated light to one or more imagers or detectors, such as infrared (IR) sensors, mid-wave infrared (MWIR) sensors, short wave infrared (SWIR) sensors, day television (DTV) cameras, etc. The optical system can have multiple curved or flat mirrors that direct light beams received through a single window to the one or more imagers or detectors, defining an optical assembly a primary optical path. In addition, the optical system can have a normal or standard configuration with a narrower field-of-view and a higher magnification (such as 4×), and a bypass or switch assembly that can transition the optical system to a wider field-of-view and a lower magnification (such as 1×). The bypass assembly can have a bypass mirror that interrupts the primary optical path to create a secondary optical path, and that can bypass one or more of the curved mirrors of the optical assembly, thus altering a magnification of the optical system. In one aspect, the bypass assembly can be compact and provided in an existing and available space of the optical system. The bypass assembly and the bypass mirror can have an extended bypass configuration and a retracted storage configuration. The bypass assembly can be articulated so that the bypass mirror can be both translated or displaced, and oriented or tilted, into the primary optical path, and between the bypass and retracted configurations.

In the retracted configuration, the bypass mirror and the bypass assembly can be disposed in an existing lateral volume between the optical system and a housing containing the optical system. The bypass assembly can be stored in a width of the wall of the housing of the optical assembly of the telescope. Thus, the bypass assembly can minimize stow volume. In another aspect, the bypass assembly can resist or control stray light reflections. For example, the bypass mirror of the bypass system can be oriented to face towards the housing and away from the optical system when oriented in the retracted configuration. Thus, the bypass assembly can minimize or control stray light reflections. In addition, the bypass assembly can be self-shuttering. Utilizing the articulated bypass assembly can also minimize exterior windows, i.e. utilize a single window, and can have both the wider and narrower field-of-views coincident for field-of-view coincidence. The bypass assembly and the bypass mirror reflects and translates a wider imager field-of-view out through a main aperture window.

FIG. 1adepicts an optical system10of a reflective, high-magnification telescope with a field-of-view bypass or switch assembly14in a retracted, storage, normal or non-bypass configuration R; whileFIG. 1bdepicts the optical system10with the field-of-view bypass assembly14in an extended or bypass configuration B. Similarly,FIG. 2adepicts the optical system10with the field-of-view bypass assembly14in the retracted configuration R; whileFIG. 2bdepicts the optical system10with the field-of-view bypass assembly14in the bypass configuration B. The optical system10with the bypass assembly14in the retracted configuration R can correspond to a normal use configuration of the optical assembly and the telescope, and a narrower field-of-view; while the optical system10with the bypass assembly14in the bypass configuration B can correspond to a wider field-of-view. The optical system10can have a housing or frame18with a single window or opening or inlet22. The window22can be faced forwardly or towards a scene or object of interest. The housing18can contain and carry multiple optics and optical elements. The optical system10and the housing18can be an existing optical system and an existing housing with a defined configuration, size, and shape with existing dimensions. In the retracted configuration R, the bypass assembly14utilizes available space in the housing18of the existing optical system and the existing housing.

FIG. 3depicts a block diagram of the optical system10in normal or standard configuration (corresponding to the bypass assembly being in the retracted configuration). The housing18contains and carries multiple optical elements, such as a curved primary mirror26, a curved secondary mirror30, a first flat mirror34, a curved tertiary mirror38, and a second flat mirror42, all together defining an optical assembly46. Other optical elements can be included in the optical assembly46, and some optical elements can be omitted based on need or desired configuration. In addition, other optical elements can be disposed outside of the housing18. In one example, these optical elements can be part of a fore optics assembly of the reflection, high-magnification telescope. While this optical assembly46and this telescope utilizes powered mirrors and flat mirrors, other telescope forms can be used.

Incident beams (i.e., light or light rays) from a scene or an object (not shown) can be passed through the single aperture or window22and reflected by the optical assembly46to one or more detectors, sensors or cameras50, either in the housing18or outside of the housing18. The optical assembly46can be arranged to define a primary optical path54to the detector(s)50. The primary optical path54can correspond to a narrower field-of-view, with the bypass assembly14in the retracted configuration R. The beams or light rays can impinge or can be incident upon the primary mirror26. Stated differently, the primary mirror26can be situated relative to the window22to receive the beams or light rays. The beams or light rays can then be reflected by the primary mirror26to the secondary mirror30; from the secondary mirror30to the first flat mirror34; from the first flat mirror34to the tertiary mirror38; from the tertiary mirror38to the second flat mirror42; and from the second flat mirror42to the one or more detectors, sensors or cameras50. Again, the configuration of the optical assembly46, and the number and types of mirror, can be varied based on the desired configuration.

The one or more detectors, sensors or cameras50, for example, can receive and transmit signals associated with the beams or the light rays to a computer system or displays (not shown) in a known manner for processing the signals. Alternatively, one detector or a multiplicity of other sensors can receive the signals. In any event, the detector can be any suitable imaging detector or sensor for a telescope, such as a CCD, CMOS, photodiode array, light emitting device or other suitable imaging sensor capable of receiving and transmitting signals pertaining to light rays.

Referring again toFIGS. 1a-2b, a lateral volume58is defined between a lateral perimeter62of the optical assembly46, or the primary optical path54, and a lateral side66of the housing18. In one aspect, the lateral perimeter62of the optical assembly46can be defined by a lateral perimeter of the primary mirror26, or the lateral perimeter of the window22, or both. The lateral direction is taken relative to a longitudinal axis of the housing18, such as that defined by the primary optical path54, and can be towards the lateral side66, as shown, or above or below depending on the configuration of the optical assembly46. In one aspect, the lateral volume58can exist in an existing configuration of the housing18and the optical assembly46, as shown. Thus, the bypass assembly14can take advantage of an existing lateral volume58. In another aspect, the housing18and the optical assembly46can be sized, shaped or located to create and define the lateral volume58. Thus, the lateral volume can be created for the bypass assembly14. The bypass assembly14can be disposed in the lateral volume58in the retracted configuration R, as shown inFIGS. 1aand2a.

FIGS. 4aand 4bdepict looking into the optical system10with the housing18removed for clarity, and with the bypass assembly14in the retracted configuration R and the bypass configuration B, respectively. Similarly,FIGS. 5aand 5bdepicts looking laterally at the optical system10, again with the housing18removed for clarity, and with the bypass assembly14in the retracted configuration R and the bypass configuration B, respectively. Similarly,FIGS. 6aand 6bdepict looking from a perspective view at the optical system10, again with the housing18removed for clarity, and with the bypass assembly14in the retracted configuration R and the bypass configuration B, respectively. The bypass assembly14can comprise a bypass mirror70movably coupled with respect to the optical assembly46(and the housing18as shown inFIGS. 1a-2b). In one aspect, the bypass assembly14can have a single bypass mirror70. The bypass assembly14can be articulated so that the bypass mirror70can be selectively translatable and tiltable, or displaceably and orientable, between the bypass orientation B and the retracted orientation R. Thus, the bypass mirror70both translates and tilts together between the orientations. The bypass configuration B and the retracted configuration R are different with respect to one another.

In the bypass configuration B, the bypass mirror70is disposed in and interrupts the primary optical path54, and is oriented to define a secondary optical path74to the detector50, as shown inFIGS. 5band 6bThe secondary optical path74can corresponding to a wider field-of-view than the primary optical path54. In one aspect, the bypass mirror70interrupts the primary optical path54in the bypass configuration B, and bypasses optical elements of the optical assembly46that magnify the image, and reduce the field-of-view. Other optical elements79can also pivot into the secondary optical path74when the bypass mirror70is in the bypass configuration B, as shown inFIGS. 1b, 2band6b.

In the retracted configuration R, the bypass mirror70is both disposed out of the primary optical path54, and is oriented transverse with respect to the bypass configuration B. Thus, the bypass mirror70is both displaced and reoriented. As mentioned above, the mirror70is both displaced and tilted together. In addition, in the retracted configuration R, the bypass mirror70can be oriented to face away from the primary optical path54and the optical assembly46. Thus, the bypass mirror70can be both positioned and oriented to oppose a lateral side of the optical assembly46in the retracted configuration. In another aspect, in the retracted configuration R, the bypass mirror70can be disposed against or can abut to the lateral side66or wall of the housing18.

Referring again toFIGS. 1a-2b, the bypass mirror70is disposed in the lateral volume58in the retracted configuration R. In addition, in the retracted configuration R, the bypass mirror70can be oriented to face towards the housing18and the lateral wall66thereof. The bypass mirror70can be both positioned and oriented to oppose the lateral wall66of the housing in the retracted configuration R. Thus, the bypass assembly14can be self-shuttering.

Thus, the bypass mirror70can be selectively translatable between two different positions, namely, a bypass position (shown with the field-of-view bypass or switch assembly14in the bypass configuration B), and a retracted position (shown with the field-of-view bypass or switch assembly14in the retracted configuration R) different from the bypass position. In the bypass position, the bypass mirror70is disposed in and interrupts the primary optical path54. In the retracted position, the bypass mirror70is disposed out of the primary optical path54. In addition, the bypass mirror70is selectively tiltable (i.e., can be tilted as needed or desired) between two different orientations, namely, a bypass orientation, and a retracted orientation different than the bypass orientation. The bypass orientation can correspond to the bypass position, and the retracted orientation can correspond to the retracted position. In the bypass orientation, the bypass mirror70is oriented to define the secondary optical path74to the detector, and can correspond to the wider field-of-view. In the retracted orientation, the bypass mirror70is oriented transverse with respect to the bypass orientation.

Referring again toFIGS. 6aand 6b, the bypass mirror70can be movable about multiple degrees of movement or freedom. For example, the bypass mirror70can swing or translate about a first axis78, and can twist or tilt about a second axis82. In addition, the bypass mirror70can be moved about the multiple degrees of movement or freedom, and between the bypass and retracted configurations B and R, by a single actuator, such as a micro motor86with a gearhead and an integral encoder. Furthermore, the second axis82itself can be moved and oriented with respect to the first axis78, as shown.

FIGS. 7aand 7bdepict looking forwardly into the bypass assembly14without the housing18and the optical assembly46, in the retracted configuration R and the bypass configuration B, respectively. Similarly,FIGS. 8aand 8bdepict looking laterally at the bypass assembly14without the housing18and the optical assembly46, in the retracted configuration R and the bypass configuration B, respectively. Similarly,FIGS. 9aand 9bdepict looking rearwardly at the bypass assembly14without the housing18and the optical assembly46, in the retracted configuration R and the bypass configuration B, respectively. Similarly.FIGS. 10aand 10bdepict looking from a lower perspective at the bypass assembly14without the housing18and the optical assembly46, in the retracted configuration R and the bypass configuration B, respectively.FIG. 11depicts the bypass assembly14partially exploded.

The bypass assembly14can further comprise a swing arm90pivotally coupled with respect to the optical assembly46(FIGS. 1a-6b) and the housing18(FIGS. 1a-3). In one aspect, the swing arm90can be pivotally coupled to a mount94, which in turn can be mounted to, carried by and disposed in the housing18(FIGS. 1a-3). Thus, the swing arm90is pendent from the mount94. The mount94and the swing arm90can be pivotally coupled together by an axle98, which can define the first axis78(FIGS. 6aand 6b). The mount94can also have offset cams stops to adjust elevation and azimuth angle of the bypass mirror70. In one aspect, the swing arm90can pivot approximately 52 degrees to translate or displace the bypass mirror70between the bypass and retracted configurations B and R. The bypass mirror70is carried by a distal end of the swing arm90. Thus, as the swing arm90pivots about the axle98, the bypass mirror70is displaced between the bypass and retracted configurations B and R. The swing arm90is selectively swingable by the motor86to position the bypass mirror70between the bypass and the retracted configurations B and R.

In addition, the bypass mirror70can be pivotally coupled to the swing arm90so that the bypass mirror70both swings or pivots along with the swing arm90, and tilts or pivots with respect to or on the swing arm90. The bypass mirror70can be pivotally coupled to the swing arm90by an axle102(FIG. 11), which can define the second axis82(FIGS. 6aand 6b). Thus, the bypass mirror70can be coupled to the axle102, and can pivot with respect to the swing arm90about the axle102, and about the second axis82. In one aspect, the axle102can extend from the bypass mirror70and into a bore at the distal end of the swing arm90, as shown inFIG. 11. A torsion spring106can be coupled to the axle102, and between the bypass mirror70and the swing arm90. The torsion spring106can bias the bypass mirror70with respect to the spring arm90, and namely towards the bypass configuration B. Corresponding tabs110and114can extend from the bypass mirror70and the swing arm90, respectively, to abut to one another in the bypass configuration B, as shown inFIGS. 7band11.

In addition, the bypass assembly14further comprises a telescoping arm118that is pivotal with respect to the optical assembly46(FIGS. 1a-6b) and the housing18(FIGS. 1a-3). The telescoping arm118is coupled to and between the bypass mirror70and the housing18, as shown inFIGS. 1band 2b. The bypass mirror70is coupled to a distal end of the telescoping arm118. In one aspect, the bypass mirror70is suspended between the swing arm90on one end and the telescoping arm118on another end. In one aspect, the telescoping arm118can have a proximal arm122configured to couple to the housing18(FIGS. 7a-11) and extending into a bore of a distal arm126coupled to the bypass mirror70. Thus, the telescoping arm118can expand and collapse or compress, with the proximal arm122compressing or collapsing into the distal arm126, and the proximal arm122expanding out of the distal arm126. The telescoping arm118can be coupled to the bypass mirror70and the housing18by ball joints so that the telescoping arm118can pivot with respect to both the bypass mirror70and the housing18. In one example, a distal ball130can extend from the bypass mirror70and into a socket of the distal arm126, while a proximal ball134can extend from the proximal arm122and into a socket of the housing18or mount on the housing.

The bypass assembly14can comprise the bypass mirror70, the swing arm90, the telescoping arm118, and the housing18. As the bypass mirror70swings on swing arm90from the bypass configuration B to the retracted configuration R, the telescoping arm118compresses or collapses, and selectively tilts the bypass mirror70against the force of the torsion spring106to orient the bypass mirror70to face away from the primary optical path54, and the optical assembly14, and towards the wall66of the housing18. As the bypass mirror70swings on the swing arm90from the retracted configuration R to the bypass configuration B, the telescoping arm118extends and allows the torsion spring106to tilt the bypass mirror70into the primary optical path54, and orients the bypass mirror70to reflect light rays along the secondary optical path74towards the detector50. Thus, the torsion spring106and the telescoping arm118work together to selectively orient the bypass mirror70as the swing arm90selectively translates the bypass mirror70.

Thus, as described above, the bypass mirror70is movable about multiple degrees of movement or freedom, such as swinging or translating about the first axis78(FIGS. 6aand 6b) by the swing arm90, and twisting or tilting about the second axis82(FIGS. 6aand 6b) by the torsion spring106and the telescoping arm118. The bypass mirror70can be both translated and tilted by the single actuator or motor86. The motor86can have an armature138coupled to the motor86, and selectively movable by the motor86, such as back and forth through a substantially 180 degree arc, perhaps best shown inFIGS. 9aand 9b. A spring link142is coupled to and between the armature138of the motor86and the swing arm90. The motor86swings the swing arm90, via the spring link142, between the retracted configuration R and the bypass configuration B. In addition, a stop146can be positioned adjacent the motor86and at an end of travel of the armature138. The stop146can be compliant to deflect under contact by the armature138to passively decelerate the armature138at the end of travel. The stop146is sized and positioned so that the armature138contacts the stop146at opposite ends of travel of the armature138. In one aspect, the stop146can have a pair of opposite wings or arms that extend in opposite directions, and each corresponding to a different end of travel of the armature138.

Referring now toFIGS. 12a-14b, another optical system of a reflective, high-magnification telescope with another field-of-view bypass or switch assembly14bis shown, which is similar in many respects to that described above, and which description is hereby incorporated herein by reference.FIGS. 12aand 12bdepict looking from a perspective view at the optical system, with the housing18removed for clarity, and with the bypass assembly14bin the retracted configuration R and the bypass configuration B, respectively. Similarly,FIGS. 13aand 13bdepict looking into the optical system, again with the housing18removed for clarity, and with the bypass assembly14bin the retracted configuration R and the bypass configuration B, respectively. Similarly,FIGS. 14aand 14bdepict looking laterally at the optical system, again with the housing18removed for clarity, and with the bypass assembly14bin the retracted configuration R and the bypass configuration B, respectively.

The bypass assembly14bcan comprise a bypass mirror70bmovably coupled with respect to the optical assembly46(and the housing). In one aspect, the bypass assembly14bcan have a single bypass mirror70b. The bypass assembly14bcan be articulated so that the bypass mirror70bcan be selectively translatable and tiltable, or displaceable and orientable (i.e., able to be oriented), between the bypass configuration B and the retracted configuration R. Thus, the bypass mirror70bboth translates and tilts together between the configurations. In the retracted configuration R, the bypass mirror70bis both disposed out of the primary optical path54, and is oriented transverse with respect to the bypass configuration B. Thus, the bypass mirror70bis both displaced and reoriented.

As mentioned above, the mirror70bis both displaced and tilted together. Unlike the bypass assembly14described above, in the retracted configuration R, the bypass mirror70bcan be oriented to face towards the primary optical path54and the optical assembly46. Thus, the bypass assembly14bcan also comprise a shutter150that folds over the bypass mirror70bin the retracted configuration R to resist stray light from reflecting off the bypass mirror70band into the optical assembly46. The shutter150can be pivotally coupled by an axle with respect to the housing and the optical assembly46. In addition, a link154can be coupled to and between the shutter150and the motor86or armature thereof. Thus, as the motor86and armature swing the swing arm90, and thus the bypass mirror70b, between the bypass configuration B and the retracted configuration R, it also folds the shutter150between an open orientation (FIGS. 12b, 13band 14b) and a closed orientation (FIGS. 12a, 13aand 14a), respectively. In one aspect, the shutter150can have a torsion spring to bias the shutter150towards the closed orientation. In another aspect, the shutter150can fold against, and can abut to, the bypass mirror70bin the retracted configuration R. In another aspect, the shutter150can have substantially the same shape and size as the bypass mirror70b. Thus, in the retracted configuration R, a perimeter of the shutter150can substantially match a perimeter of the bypass mirror70.

As described above, the bypass mirror70bcan be biased in the bypass position of the bypass configuration B by the torsion spring. The bypass mirror70bcan be tilted from the bypass configuration B to the retracted configuration R by interaction with the lateral side or wall66of the housing18. Thus, as the bypass mirror70bis swung to the retracted configuration R it abuts to the lateral side or wall66of the housing18to tilt the bypass mirror70bto the retracted position of the retracted configuration R. In one aspect, the bypass mirror70bcan have a cam surface or wheel158on an edge thereof to facilitate interaction with the lateral side or wall66of the housing18.

Although the disclosure may not expressly disclose that some embodiments or features described herein may be combined with other embodiments or features described herein, this disclosure should be read to describe any such combinations that would be practicable by one of ordinary skill in the art. The user of “or” in this disclosure should be understood to mean non-exclusive or, i.e., “and/or,” unless otherwise indicated herein.