CN117795394A

CN117795394A - Apparatus for protecting optical device from contamination

Info

Publication number: CN117795394A
Application number: CN202280055140.1A
Authority: CN
Inventors: 妮玛·纳巴维; 伊恩·劳·贝尔; 茹班·纳耶里; 科林·亚历山大·纽利
Original assignee: Excellent Sensing Technology Co
Current assignee: Excellent Sensing Technology Co
Priority date: 2021-06-08
Filing date: 2022-06-02
Publication date: 2024-03-29

Abstract

An apparatus for protecting an optical device from contamination is disclosed. The apparatus includes a window disposed between the optical device and the contaminated environment, the window rotatable about an axis of rotation and including an outward facing surface curved in at least one direction about the axis of rotation. The apparatus also includes a bezel surrounding a portion of the outward facing surface and defining a light-passing aperture for transmitting electromagnetic radiation to or from the optical device. The bezel includes a seal extending around a perimeter of the light aperture and is configured to cause the seal to conform to an outer surface when the window and bezel are urged into contact with one another. The device also includes an actuator operable to cause relative rotation between the window and the bezel to move the outward facing surface relative to the bezel. The apparatus further includes a seal configured to dispense a film to a portion of the outward facing surface that enters the light-passing aperture during relative rotation, the film being operable to reduce binding of optical contaminants within the light-passing aperture to the outward facing surface while transmitting electromagnetic radiation to or from the optical device through the light-passing aperture. The seal is configured to remove contaminants entrained in the film or adhered to a portion of the outward facing surface that moves out of the light passing aperture during relative rotation.

Description

Apparatus for protecting optical device from contamination

Technical Field

The present disclosure relates generally to optical devices, and more particularly to cleaning of optical surfaces in optical devices.

Background

Cameras, rangefinders and other optical devices typically have at least one optical surface exposed to the surrounding environment. The exposed optical surface may be an outer surface of an optical-grade window, lens, or other optical element that surrounds the housing and transmits light to or from the optical device within the housing. The optical element thus protects the sensitive optical components enclosed within the housing. However, over time, the exposed optical surfaces may accumulate contaminants that reduce optical performance, such as water, dust particles, and other debris. In the case of optical surfaces exposed to harsh environments, the optical surfaces may quickly become contaminated and cannot rely on periodic manual cleaning. This is particularly problematic in mining and other industrial environments or in remote installations where manual cleaning of the access optics may be difficult or dangerous. In some applications, the lack of manually cleaned channels may actually hinder the deployment of the optical device.

There remains a need for an apparatus and method for automatically cleaning optical surfaces.

Disclosure of Invention

According to one disclosed aspect, an apparatus for protecting an optical device from contamination is provided. The apparatus includes a window disposed between the optical device and the contaminated environment, the window rotatable about an axis of rotation and including an outward facing surface curved in at least one direction about the axis of rotation. The apparatus also includes a bezel surrounding a portion of the outward facing surface and defining a light-passing aperture for transmitting electromagnetic radiation to or from the optical device. The bezel includes a seal extending around a perimeter of the light aperture and is configured to cause the seal to conform to an outer surface when the window and bezel are urged into contact with one another. The device also includes an actuator configured to cause relative rotation between the window and the bezel to move the outward facing surface relative to the bezel. The apparatus further includes a seal configured to dispense a film to a portion of the outward facing surface that enters the light-passing aperture during relative rotation, the film being operable to reduce binding of optical contaminants within the light-passing aperture to the outward facing surface while transmitting electromagnetic radiation to or from the optical device through the light-passing aperture. The seal is configured to remove contaminants entrained in the film or adhered to a portion of the outward facing surface that moves out of the light passing aperture during relative rotation.

The outward facing surface may be curved circularly in at least one direction about the axis of rotation.

The membrane may comprise a liquid membrane that remains liquid after being dispensed.

The device may include a reservoir in liquid communication with the seal, and the seal may be configured to dispense a thin film of liquid under the seal during relative rotation between the window and the bezel, while containing the liquid in the reservoir when not rotated between the window and the bezel.

The window and the optical device may be enclosed within a housing, and the reservoir may be defined within a portion of the housing extending from a seal in the bezel along a portion of the outward facing surface of the window disposed within the housing to a rear seal configured to contain liquid in the reservoir and prevent liquid from reaching other portions of the housing.

The film may comprise one of the following: a liquid material that at least partially solidifies after being dispensed; a liquid material and a non-liquid material, the liquid material being operable to at least partially evaporate after being dispensed; or a non-liquid material that can be dispensed during relative rotation by grinding from the seal to form a film.

The seal may include: a dispenser portion operable to dispense a film to a portion of the outward facing surface that enters the light passing aperture during rotation of the window; and a wiper portion operable to remove contaminants entrained in the film or adhering to a portion of the outward facing surface that moves out of the light passing aperture during rotation of the window.

The dispenser portion of the seal and the wiper portion of the seal may be disposed on opposite sides of the bezel and rotation of the window may be in a direction to move the outward facing surface toward the wiper portion of the seal.

The wiper portion of the seal may include a wiper extending around the entire perimeter of the light aperture, and the dispenser portion of the seal may include a separate seal disposed spaced outwardly from the wiper.

The optical device and the window may be enclosed within a housing, and the bezel may comprise a portion of the housing.

The device may include a compliant structure acting on the window and configured to provide a force for urging the window into contact with the bezel.

The outer facing surface may be rounded in at least one direction about the axis of rotation and the outer facing surface is further rounded in a direction orthogonal to the at least one direction to define a spherical outer facing surface, and the bezel may include a rounded bezel.

The actuator may be configured to cause rotation of the window in a single direction about the axis of rotation, and the rotation causes the seal to remove contaminants from a first portion of the outward facing surface that moves out of the light passing aperture, while the dispenser supplements the film on a second portion of the outward facing surface that enters the light passing aperture.

The window may comprise a spherical solid and the optical device may be disposed behind the spherical solid and electromagnetic radiation may be transmitted to or from the optical device through the light passing aperture and the spherical solid.

The apparatus may include a volume of immersion liquid contained between a portion of the spherical solid and a first optical element of the optical device, the immersion liquid having an index of refraction selected to substantially match an index of refraction of the spherical solid.

The spherical solid may include a recess disposed within the spherical solid, and the optical device may be disposed at least partially within the recess.

The window may include an inwardly facing surface that may be curved in at least one direction about the axis of rotation to define a curved wall between the outwardly facing surface and the inwardly facing surface.

The curved wall may extend beyond the light-passing aperture and the actuator may be configured to cause reciprocal rotation of the window about the axis of rotation, rotation in a first direction may cause the seal to remove contaminants when a first portion of the outward facing surface moves out of the light-passing aperture and rotation in a second direction may cause the seal to dispense the film to a first portion of the outward facing surface upon re-entering the light-passing aperture.

The seal may surround the light aperture and rotation in a first direction may cause the seal to dispense the film to a second portion of the outward facing surface that enters the light aperture and rotation in a second direction may cause the seal to remove contaminants entrained in the film or adhered to the second portion of the outward facing surface upon removal from the light aperture.

The curved wall of the window may include a spherical shell extending about the axis of rotation to define an enclosed region within the curved wall.

The apparatus may include at least one optical element disposed within the enclosed region to transmit electromagnetic radiation to the optical device.

The optical device may be disposed outside the enclosed region, and the optical element includes one of: one or more lenses configured to condition electromagnetic radiation transmitted to or from the optical device; or a mirror comprising a reflective surface arranged to redirect electromagnetic radiation incident on the reflective surface to or from the optical device.

The optical device may be disposed outside of the enclosed region and the spherical shell may include at least one opening and the at least one optical element may be mounted on a support structure that extends through the at least one opening to the enclosed region to support the at least one optical element in fixed relation to the optical device.

The apparatus may include an immersion liquid received within the enclosed region, the immersion liquid having a refractive index substantially matching a refractive index of the window.

The optical device may be disposed within the enclosed region.

The outward facing surface of the window may comprise a cylindrical surface.

The cylindrical surface may comprise a circular cylindrical surface.

The electromagnetic radiation transmitted to or from the optical device may comprise electromagnetic radiation having a wavelength of at least one of: an ultraviolet wavelength range; a visible wavelength range; an infrared wavelength range; long-wave infrared wavelength range; or an x-ray wavelength range.

The actuator may be configured to cause one of: a continuous relative rotation; intermittent relative rotation; or relative rotation in one direction followed by relative rotation in the opposite direction.

The window may include a housing including a spherically-facing outer surface, and the bezel may include a circular bezel, and the actuator may be configured to cause rotation of the window about an axis of rotation aligned at an acute angle with the optical axis of the imaging device to move the facing outer surface through the light aperture.

The shell may include one of a spherically-facing inner surface or an aspherically-facing inner surface.

The optical device may be disposed within the housing behind one of the spherically-facing inner surface or the non-spherically-facing inner surface.

The axis of rotation may pass through a point outside the light passing hole.

The direction of rotation of the window about the axis of rotation may be selected to move the window relative to the bezel in a direction such that the contaminant moves downwardly out of the light aperture.

The apparatus may include an actuator configured to produce a secondary motion to remove at least some contaminants that accumulate at the perimeter of the light passing aperture.

The seal may be manufactured in a circular shape and the seal may be mounted within the bezel such that the seal is urged into a non-circular shape.

The optical device may include a plurality of optical devices configured to transmit or receive electromagnetic radiation.

Other aspects and features will become apparent to those ordinarily skilled in the art upon review of the following description of specific disclosed embodiments in conjunction with the accompanying figures.

Drawings

In the drawings illustrating the disclosed embodiments,

FIG. 1A is a perspective view of an apparatus for protecting an optical device from contamination according to a first disclosed embodiment;

FIG. 1B is a cross-sectional view of an apparatus for protecting an optical device from contamination taken along line A-A in FIG. 1A;

FIG. 1C is a further cross-sectional view of the apparatus of FIG. 1A;

FIG. 2 is a cross-sectional view of an apparatus for protecting an optical device from contamination according to an alternative disclosed embodiment;

FIG. 3 is a cross-sectional view of another embodiment of an apparatus for protecting an optical device from contamination;

FIG. 4 is a cross-sectional view of yet another embodiment of an apparatus for protecting an optical device from contamination;

FIG. 5 is a cross-sectional view of an alternative embodiment of an apparatus for protecting an optical device from contamination;

FIG. 6A is a partially cut-away perspective view of a further embodiment of an apparatus for protecting an optical device from contamination;

FIG. 6B is a perspective cross-sectional view of the device shown in FIG. 6A, taken along line B-B;

FIG. 7A is a perspective view of an alternative embodiment of an apparatus for protecting an optical device from contamination;

FIG. 7B is a cross-sectional view of the device shown in FIG. 7A;

FIG. 8A is a perspective view of a further embodiment of an apparatus for protecting an optical device from contamination;

FIG. 8B is a cross-sectional view of the device shown in FIG. 8A;

FIG. 8C is a partially cut-away perspective view of the apparatus shown in FIG. 8A; and is also provided with

Fig. 8D is a rear perspective view of a portion of the apparatus shown in fig. 8A.

Detailed Description

Referring to fig. 1A, an apparatus for protecting an optical device 102 from contamination according to a first disclosed embodiment is shown generally at 100. The apparatus 100 includes a window 104 disposed between the optics 102 and a contaminated environment 106. Window 104 is rotatable about an axis of rotation 108, as indicated by arrow 110. Window 104 includes an outward facing surface 112 that curves in at least one direction about rotational axis 108. The apparatus 100 also includes a bezel 114 that encloses a portion of the outward facing surface 112 and defines a light passing aperture 116 (shown in phantom) for transmitting electromagnetic radiation, such as light, to the optical device 102 or from the optical device 102 through the window 104. The optical device 102 has an optical axis represented by line 144.

In this embodiment, window 104 is made of a substantially optically transparent material over a range of operating wavelengths associated with optical device 102. The term "substantially optically transparent" should be considered to refer to a material that has low attenuation of light passing through the optical device 102. In this context, the term "light" is to be understood as referring to electromagnetic radiation having a wavelength in the visible wavelength range, the infrared wavelength range, the ultraviolet wavelength range or the x-ray wavelength range. In some embodiments, the wavelength range may be any of an ultraviolet wavelength range, a visible wavelength range, an infrared wavelength range, a long-wavelength infrared wavelength range, or an x-ray wavelength range.

In the illustrated embodiment, the outward facing surface 112 is curved circularly in a direction 110 about the rotational axis 108. In this embodiment, the outward facing surface 112 is also curved circularly in a direction shown by arrow 118 about an axis of rotation 120 orthogonal to the axis 108, thus defining a spherical outward facing surface 112. In the illustrated embodiment where window 104 has a spherically-facing outer surface 112, bezel 114 has a substantially circular shape.

A cross-sectional view of the apparatus 100 taken along line A-A coincident with the optical axis 144 in fig. 1A is shown in fig. 1B. Typically, the device 100 is enclosed in a housing, however in fig. 1A and 1B, the housing is omitted to show the elements of the device 100 that are obscured by the housing. The bezel 114 includes a seal 122 extending around the perimeter of the light aperture 116. Bezel 114 is configured such that seal 122 conforms to face outer surface 112 when window 104 and bezel 114 are urged into contact with each other. In the illustrated embodiment, the seal 122 includes a separate dispenser portion 124 and wiper portion 126. In other embodiments, the seal 122 may be an integral element that provides the functionality described in more detail below.

Referring back to fig. 1A, the device 100 also includes an actuator 128, the actuator 128 being operable to cause relative rotation between the window 104 and the bezel 114. In the illustrated embodiment, the rotation is about an axis of rotation 108, in this embodiment, the axis of rotation 108 is perpendicular to the optical axis 144. The actuator 128 may be implemented using a motor, the actuator 128 being coupled to the window 104 via a shaft 130. The actuator is operable to transmit rotational torque 132 to the window via the shaft 130, which causes the outward facing surface 112 to move relative to the bezel 114. Torque 132 may be applied to cause rotation in a clockwise direction, a counter-clockwise direction, or a combination of clockwise and counter-clockwise directions. The rotation may be continuous or intermittent, or any combination of the two.

Referring again to fig. 1B, in the illustrated embodiment, rotational torque 132 transmitted by the actuator 128 to the shaft 130 causes a portion of the outward facing surface 112 to move downward into the light aperture 116. In other embodiments, the movement of the outward facing surface 112 may be upward, sideways, or may be reciprocating, as described in more detail below. During relative rotation, the seal 122 distributes the film to a portion of the outward facing surface 112 that enters the light aperture 116 (in this case, at the top of the light aperture). The film is operable to reduce the binding of optical contaminants within the light passing aperture 116 to the outward facing surface while transmitting light through the light passing aperture to the optical device 102 or from the optical device 102.

In one embodiment, the film may be a liquid film, and the dispenser portion 124 of the seal 122 may be configured to primarily perform the function of dispensing a thin and substantially uniform film on the outward facing surface 112 of the window 104. Various configurations of suitable dispenser portions 124 of the seal 122 are disclosed in commonly owned U.S. provisional patent application No. 63/042472 entitled "apparatus for cleaning optical surfaces in an optical device," filed on 6/22 of 2020, the entire contents of which are incorporated herein by reference. Suitable liquids for providing a liquid film, which may have properties that cause the liquid to uniformly wet the outward facing surface 112 of the window 104, are also disclosed in US 63/042472. Suitable liquids may remain stable under the environmental conditions to which the device 100 will be subjected. It may also be desirable that the adhesion between the liquid and the outward facing surface 112 be greater than the adhesion between the liquid and typical contaminants. Under these conditions, many typical contaminant particles will tend to float within the liquid film, rather than adhere to the outward facing surface 112. Other liquid properties that may be desirable include stable viscosity, low vapor pressure, and hydrolytic stability, depending on the application.

In one embodiment, the liquid may be hydraulic oil. In some embodiments, the hydraulic oil may include a component, such as silicone, that imparts a hydrophobic character to the liquid film, which reduces the likelihood of water being entrained within the liquid film. These liquids will tend to float the water droplets on top of the liquid film where they can be easily removed by the wiper 126 rather than passing under the wiper. In addition, the liquid should also have suitable optical properties. As an example, the liquid may be selected based on a high optical transmittance in a wavelength range associated with the optical device 102. The liquid may also be selected to have a refractive index that is close to the refractive index of the material of the window 104, which reduces the optical effects of scratches in the outward facing surface 112.

The liquid film may remain liquid after being dispensed on the outward facing surface 112 and will cause negligible or minimal degradation to the image captured by the liquid film. In other embodiments, the selected liquid material may at least partially solidify after being dispensed. Alternatively, the liquid material may include a non-liquid material, and the liquid material may at least partially evaporate after being dispensed, leaving the non-liquid material on the outward facing surface 112.

In other embodiments, the non-liquid material may be dispensed during relative rotation by grinding from the seal 122 to form a film. As an example, the entire seal 122 or the dispenser portion 124 of the seal may be made of a material that leaves behind a film when pulled across the outward facing surface 112. One example of such a material is a polysiloxane-based material, which can be manufactured in various forms and can contain a crosslinked polymer that can be used as a sealing element.

The seal 122 is also configured to remove contaminants entrained in the film or adhered to a portion of the outward facing surface 112 that moves out of the light aperture 116 (in this case, at the bottom of the light aperture 116) during relative rotation. In this embodiment, the wiper portion 126 of the seal 122 performs primarily this function, and includes an edge 134, the edge 134 closely contacting the outward facing surface 112 and causing the film and contaminants to be carried away from the outward facing surface. Various configurations of suitable wiper portions 126 are disclosed in U.S. provisional patent application 63/042472. In the embodiment shown in fig. 1A and 1B, the wiper portion The segment 126 extends around the entire perimeter of the light aperture 116. The dispenser portion 124 includes a separate sealing element disposed outwardly spaced from the wiper portion 126. In some embodiments, the wiper portion 126 may be formed from a compliant material (such as polyurethane, polyethylene (UHMW), or acetal) Is prepared by the method. In some embodiments, the material of the seal 122 may be further processed to further improve its properties to prevent the possibility of contaminants from accumulating and adhering to the seal. The treatment may be applied to the wiper 126 or the dispenser portion 124 or to both the wiper and the dispenser portion. It is generally desirable to direct contaminants away from the light-passing aperture of the window, and the hydrophobic treatment at the seal may help prevent accumulation due to contaminants adhering to the wiper or dispenser material. For example, the treatment may involve various treatments or coating applications to the wiper 124 and/or dispenser portion 126 of the seal 122 to reduce friction or alter oleophobic or hydrophobic properties.

In some embodiments, contaminants removed from the light passing apertures 116 may inevitably accumulate at the peripheral edge of the outward facing surface 112 over time. This contaminant build-up may be generally located in the lower region of the light passing aperture 116, particularly for embodiments where the wiper portion is positioned to prevent redeposition on the outward facing surface 112 under the force of gravity. In one embodiment, the device 100 may generate a secondary motion to periodically attempt to remove any build up of contaminants and direct the contaminants away from the light passing aperture 116. The secondary motion may take the form of an impact or vibration transmitted by the actuator to the housing, bezel 114, window 104, or other component associated with cleaning aperture 116 of device 100. The actuator may be a vibration motor, a piezoelectric actuator, a solenoid, or other device capable of producing a secondary motion. In one embodiment, window rotary actuator 128 may be controlled to produce a small oscillating secondary motion to window 104. The oscillating motion relative to contaminant accumulation at the edge of the light passing aperture 116 may be sufficient to remove at least some contaminants.

Some contaminant particles may adhere directly to the outward facing surface 112 and may be more difficult to remove. In addition, some recalcitrant contaminants (such as sap or resin) may be difficult to remove once adhered to the outward facing surface 112. In embodiments where the potential contaminants include these more recalcitrant contaminants, the wiper may be made of a metallic material. For example, the wiper portion 126 may be made of a metallic material (such as a brass alloy, a stainless steel alloy, or a porous metal alloy impregnated with a lubricant).

In the embodiment shown in fig. 1A and 1B, window 104 is made of an optically transparent material as a spherical solid. The optical device 102 is disposed behind the window 104 and light is transmitted to or from the optical device through the light passing aperture 116 and the window 104. In this embodiment, the optical device 102 includes a sensor 136 and a lens 138, the lens 138 being disposed between the window 104 and the optical device 102 for conditioning light and directing the light to the sensor 136. The solid spherical window 104 has a focal length proportional to the radius of the sphere, and the lens 138 must be configured to work in conjunction with the window 104 to direct light to the sensor 136. Thus, the lens 138 may include a plurality of lens elements, at least some of which are included to correct for the spherical window that is present.

In one embodiment, the apparatus 100 may include a volume of immersion liquid 140, the volume of immersion liquid 140 being contained within a chamber 142 between the rear portion of the spherical solid window 104 and the first optical element (i.e., lens 138) of the optical device. When the immersion liquid is selected to have an index of refraction that matches that of window 104, the optical effects of the rear surface of spherical window 104 are effectively removed, thus reducing the likelihood of introducing optical aberrations and simplifying the design of lens 138. The refractive index of the immersion liquid need not be exactly matched and as long as the refractive index of the immersion liquid is closer to the refractive index of the window material than the refractive index of air (refractive index of about 1.0), the optical effect of the rear surface of the window will be reduced.

Referring to fig. 1C, a portion of the device 100 is shown with a film 160, the film 160 having been dispensed to the outward facing surface 112 of the window 104. Several contaminant particles 162 are also shown as being entrained or embedded within the membrane 160. In this embodiment, the apparatus 100 is configured to cause rotation of the window about the rotation axis 108 in a single counterclockwise direction in the direction of the applied torque 132. The rotation 132 causes the outward facing surface 112 of the window 104 to move in the direction shown by arrow 164 such that the wiper portion 126 of the seal 122 removes the contaminant 162 from the first portion 168 of the outward facing surface that moves out of the light aperture. At the same time, the dispenser portion 124 of the seal 122 supplements the film on a second portion of the outward facing surface that enters the light passing aperture. This embodiment has the advantage that if the device is oriented as shown in fig. 1A-1C, any removed contaminants 162 that accumulate at the edge 134 of the wiper 126 will be less likely to redeposit within the light passing aperture 116. As an example, if the direction of rotation is reversed such that contaminants accumulate at the upper edge of the light passing aperture 116, these contaminants may redeposit under gravity on the outward facing surface 112.

In the embodiment shown in fig. 1A-1C, the wiper 126 and dispenser portion 124 of the seal 122 extend around the entire light aperture 116. In an alternative embodiment, shown at 200 in fig. 2, the seal is configured to include a dispenser 202 and a wiper 204, each disposed on opposite sides of a modified bezel 206. The upper portion of the bezel 206 is modified to receive the dispenser 202, while the dispenser is omitted from the lower portion of the bezel. The dispenser 202 and wiper 204 may be manufactured separately or may be integrally molded seals. The dispenser 202 may extend around an upper semi-circular peripheral portion of the light aperture 116, while the wiper 204 extends around a lower semi-circular peripheral portion of the light aperture 116. Alternatively, the proportion of the light passing aperture 116 occupied by the dispenser 202 and the wiper 204 may not be equal. Rotation of window 104 in a direction caused by applied torque 132 causes outward facing surface 112 to move toward wiper 204 for contaminant removal and away from dispenser 202 for dispensing film 160, generally as described in connection with the embodiment of fig. 1C.

Referring to fig. 3, an alternative embodiment of an apparatus for protecting an optical device is shown generally at 300 in fig. 3. The apparatus 300 includes a window 302 fabricated as a spherical solid. Window 302 includes a recess 304 formed in a solid body for receiving a lens tube 306, the lens tube 306 containing one or more lenses 308 for forming an image on a sensor 310 of an optical device 312. In one embodiment, window 302 may be fabricated by drilling recess 304 into a solid sphere. In this embodiment, after lens tube 306 is inserted and secured within recess 304, cap 314 is bonded within the rear end of the recess to provide enclosed region 316 within window 302. The cap 314 may be formed or subsequently ground to maintain the spherical shape of the window 302. In the embodiment shown in fig. 3, the sensor 310 portion of the optical device 312 remains outside of the recess. In some embodiments, one or more additional optical elements 318 may be disposed between the sensor 310 and the lens tube 306 within the recess.

The embodiment of fig. 3 has the advantage of positioning lens tube 306 and lens 308 close to light-passing aperture 116, thus helping to capture light from a wide field of view. The potential field of view through the light passing aperture 116 is represented by dashed line 320 in fig. 3.

In operation of the apparatus 300, an actuator (not shown) may be configured to cause reciprocal rotation of the window 302 about the axis of rotation 322. Rotation in the first direction 324 causes the lower portion of the wiper 126 to remove contaminants 326 as the first portion 328 of the outward facing surface 112 moves out of the light aperture 116. Subsequent rotation in the second direction 330 causes the dispenser portion 124 to dispense film to a first portion 328 of the outward facing surface 112 upon re-entering the light aperture 116. During the reciprocating rotation, the lens tube 306 moves off-axis and the lens 308 will not be operable to direct light to the sensor 310. The operation of the optical device 312 is thus interrupted during the cleaning cycle. A rotational stop (not shown) may be required to ensure that the lens tube 306 returns to a position sufficiently aligned with the imaging axis 332 of the optical device 312 to meet imaging tolerances. While the embodiment of fig. 3 has described reciprocal rotation of window 302 about rotation axis 322, rotation of the window may be in a single direction of rotation.

In embodiments in which the wiper 126 and dispenser portion 124 surround the light aperture 116, rotation in the first direction 324 causes the dispenser 124 to dispense film to a second portion 332 of the exterior surface 112 that enters the light aperture 116. Similarly, rotation in the second direction causes wiper 126 to remove any contaminants entrained in the film or adhered to the second portion of outward facing surface 112 upon removal from light passing aperture 116.

Referring to fig. 4, another embodiment of an apparatus for protecting an optical device is shown at 400. In this embodiment, the window 402 has a curved wall 404 that extends beyond the light aperture 116, but is truncated behind the wiper 126 and dispenser 124. The window 402 is curved about the axis of rotation 322 and also curved in a direction orthogonal to the axis of rotation. Window 402 is thus configured as a truncated shell, or in this particular embodiment as a hemispherical shell. The lens tube 406 and the lens 408 are disposed at substantially the same position relative to the outward facing surface 112. However, in this embodiment, the lens tube 406 extends upwardly to the optical device 312, the lens tube 406 supporting the optical device 312 in a fixed relationship with the lens tube 406. The lens 318 (shown in fig. 3) and the optical device 312 may be moved forward toward the rear end of the lens tube 406. This configuration provides a field of view 410 similar to the embodiment of fig. 3.

During the cleaning cycle, operation is substantially similar to the embodiment of fig. 3, except that only window 402 undergoes reciprocal rotation and lens tube 406 and optics 312 remain stationary. Thus, this embodiment provides for uninterrupted operation of the optical device 312.

Referring to fig. 5, a further embodiment of an apparatus for protecting an optical device is shown at 500. In this embodiment, window 502 has a curved wall 504 extending about an axis of rotation 506. Window 502 is curved about an axis of rotation 506 and also curved in a direction orthogonal to the axis of rotation. Window 502 is thus configured as a spherical shell having an enclosed region 508 within curved wall 504. The curved wall 504 includes an opening 512 that is concentrically positioned relative to the rotational axis 506. The optical device 514 is arranged laterally with respect to the window 502 and comprises a lens tube 516 for mounting one or more lenses 518 (in this case a plurality of lenses) for conditioning and/or directing the light to the sensor 520. In the illustrated embodiment, an optical element 522 in the form of a mirror is disposed within the region 508 surrounded by the curved wall 504. In this embodiment, the mirror 522 is disposed at 45 ° to the imaging axis 524. The mirror 522 includes a reflective surface that redirects light incident on the reflective surface captured through the light passing aperture 116 and directs the light through the opening 512. Light passing through the opening 512 passes through the lens tube 516 and to the sensor 520. The opening 512 is sized to prevent light redirected by the mirror 522 from being incident on portions of the curved wall 504.

One advantage associated with the embodiment shown in fig. 5 is that light passes through only a single thickness of the curved wall 504 of the window 502. As disclosed above, the solid spherical window of fig. 1A-1C may introduce some optical design limitations that may be reduced or avoided in this embodiment. Although a single optical element 522 is shown in fig. 5, curved wall 504 may be configured to receive one or more optical elements, including elements such as lenses, curved mirrors, prisms, and other optical elements. In some embodiments, the size of the optic 514 may facilitate mounting the optic partially or entirely within the region 508.

During the cleaning cycle, rotation of window 502 is caused by torque transmitted by actuator 510 in a direction about rotational axis 506. During rotation, the opening 512 remains concentrically aligned with the axis of rotation, facilitating uninterrupted operation of the optical device 514. The dispenser portion 124 and wiper 126 of the seal 122 may extend around the perimeter of the light aperture 116 as described above in connection with the embodiments shown in fig. 1A-1C and 2. The rotation about the rotation axis 506 may be in one direction, although reciprocating rotation may also be implemented.

In any of the embodiments described herein with reference to an optical device having a sensor for receiving light through a respective light-passing aperture, it should be understood that the optical device may alternatively comprise a light source that generates light and directs the light out through the light-passing aperture. Thus, the optical device may comprise an illuminator, such as a light emitting diode or a laser, or the like. Further, the sensor may be configured to produce an image (e.g., a CMOS image sensor), but may also be a photosensor or other detector configured to produce a signal in response to variations in the intensity of light captured through the light passing aperture or the frequency or phase of light incident on the sensor. In some embodiments, window 104 may cover multiple optical devices. The optical device 102 may include any combination of electromagnetic radiation emitters or detectors, or a plurality of combinations thereof. One example is a camera and a light source for illuminating the field of view of the camera. Another example is a light source (such as a laser or light emitting diode) and a photodetector that senses electromagnetic radiation reflected back through window 104.

Referring to fig. 6A, another embodiment of an apparatus 600 for protecting an optical device 602 is shown in a cut-away perspective view. A cross-sectional view of the device 600 taken along line B-B in fig. 6A is shown in fig. 6B. In this embodiment, the optical device 602 includes an image sensor 604, such as a CMOS image sensor. The apparatus 600 also includes additional image processing circuitry stacked on the circuit substrate 606 behind the optical device 602 for processing the image signals generated by the image sensor 604. The apparatus 600 includes an electrical connector 608, as best shown in fig. 6B, for connecting power to the optical device 602 and the circuit substrate 606, and for transmitting image signals back to a host system (not shown).

The apparatus 600 includes a window 610 disposed between the optical device 602 and a contaminated environment 612. In this embodiment, window 610 is configured as a hollow spherical shell. Window 610 includes an outward facing surface 614 curved about an axis of rotation 616. The outward facing surface 614 is also curved in a direction normal to the axis of rotation to define a spherical outward facing surface. A circular bezel 618 surrounds the outward facing surface 614 and defines a light passing aperture 620 for transmitting light to the optical device 602. In this embodiment, the apparatus 600 and the optics 602 are enclosed within a housing 622, and the bezel 618 and the housing are manufactured as an integral unit. In other embodiments, the housing 622 and the bezel 618 may be implemented as separate connection elements. The housing 622 has an opening at the rear closed by a rear cover plate 624, the rear cover plate 624 also carrying the electrical connector 608. A seal 626 is mounted within the bezel 618. As described above in connection with the embodiment shown in fig. 1A and 1B, the seal 626 includes a dispenser portion 628 and a wiper portion 630.

As best shown in the cross-sectional view of fig. 6B, window 610 includes an inward facing surface 632 that is also curved about axis of rotation 616. The inward facing surface 632 is further curved normal to the axis of rotation to define a curved wall 634, thereby defining a spherical shell of the window 610. The spherical shell has an opening 636 in the wall 634 that receives the enclosure 638. The enclosure 638 may be secured within the opening 636 by using an adhesive to bond the enclosure to the wall 634. In this embodiment, curved wall 634 of window 610 thus extends about axis of rotation 616 and defines enclosed region 642 within the spherical shell. In this embodiment, the lens tube 644 is enclosed within this region and includes at least one optical element. In this embodiment, the lens tube 644 includes a plurality of optical elements 646 for capturing light through the light passing aperture 620 and directing the light to the image sensor 604 or the optical device 602.

In this embodiment, the device 600 includes a cup 648 (shown partially cut away in fig. 6A), the cup 648 surrounding the window 610. Cup 648 includes a rear seal 650 that engages a rear portion of curved wall 634 of window 610. Cup 640 is urged forward in housing 622 by a plurality of springs 652. One of the plurality of springs 652 is shown in cross-section in fig. 6B. The spring 652 is received on a guide pin 654, and one end of the guide pin is received within a hole 656 formed in the back cover plate 624. The other end of the guide pin 654 is threaded into the rear of the cup 648. When the back cover plate 624 is inserted into the housing 622, the spring pushes the cup 648 toward the bezel 618, supporting the back seal 648 on the window 610 and thus also urging the outward facing surface 614 of the window 610 into contact with the dispenser portion 628 of the seal 626. The springs 652, guide pins 654, and apertures 656 act as compliant structures that act on the window 610 to provide a force for urging the window into contact with the bezel 618.

The lens tube 644 is mounted within a lens support structure 658 that extends 658 through the opening 636 into the enclosure region 642. The lens support structure 658 may be sealingly received within a bore 660 in the enclosure 638 and secured to the cup 648 via fasteners 662. The lens support structure 658 supports the lens tube 644 and the plurality of optical elements 646 in fixed relation to the optical device 602. In the illustrated embodiment, the optical device 602 may be secured to the back cover plate 624, which has the advantage of providing easy assembly and disassembly of the apparatus 100. In other embodiments, where more precise registration is desired between the lens support structure 658 and the optical device 602, the optical device may be secured to the cup 648.

The interior region between cup portion 640 and curved wall 634 of window 610 defines a reservoir 664 for containing liquid that is dispensed as a film to light passing aperture 620 to reduce the incorporation of optical contaminants into outward facing surface 614. The reservoir 664 is in fluid communication with a dispenser portion 628 of the seal 626, the dispenser portion 628 being configured to dispense a thin film of liquid under the seal during relative rotation between the window and the bezel, and to contain liquid in the reservoir when there is no rotation between the window and the bezel.

In this embodiment, the reservoir 664 extends entirely around the curved wall 634 of the window 610 from the dispenser portion 628 of the seal 626 to the rear seal 650. Thus, the seals 628, 650 contain the liquid within the reservoir 664 and prevent the liquid from reaching other portions of the housing 622, such as the optical device 602. The volume of the reservoir 664 may be configured to hold enough liquid to facilitate operation of the device through a reasonable number of cleaning cycles. In one embodiment, the volume of liquid contained may be sufficient to satisfy the useful life of the device 600. In other embodiments, the housing may include ports (not shown) for periodically replenishing the liquid.

The device 600 further includes an actuator 666 operable to cause relative rotation between the window 610 and the bezel 618 to move the outwardly facing surface 614 relative to the bezel. In this embodiment, the actuator 666 includes a motor 668, which motor 668 is coupled to a shaft 674 via a pair of gears 670, 672. The shaft 674 is coupled to the wall 634 of the spherical shell window 610 through an opening 676 in the cup 648. When motor 668 is activated, torque is transferred to shaft 674 via gears 670, 672, which rotates window 610 in direction 678 about rotational axis 616. The liquid in the reservoir 664 wets the dispenser portion 628 and the wiper portion 630, which reduces rotational friction as the dispenser portion 628 dispenses a film of liquid on a portion of the outward facing surface 614 that enters the light aperture 620.

An enclosure 638 in an opening 636 in a wall 634 of the window 610 seals the enclosure region 642 and prevents liquid from reaching the lens tube 644 from the reservoir 664. In another embodiment, the immersion liquid may be received within the enclosed region 642. The immersion liquid may be selected to have a refractive index that substantially matches the refractive index of the window 610, thus reducing internal reflection between the optical surfaces in the enclosed region and reducing the likelihood of optical aberrations. The refractive index of the immersion liquid need not be exactly matched and reflection and aberrations will be reduced at least to some extent as long as the refractive index of the immersion liquid is closer to the refractive index of the window and the optical material of the optical element than air (refractive index of about 1.0).

In the embodiment shown in fig. 6A and 6B, the optical device 602 is disposed outside of the enclosed region 642, while the lens tube 644 and the optical element 646 associated with the optical device 602 are disposed inside of the enclosed region. In other embodiments where the dimensions of the optical device 602 allow, the optical device may also be disposed within the enclosure 642 (not shown).

Referring to fig. 7A, a further embodiment of an apparatus for protecting an optical device is shown at 700. The device 700 includes a window 702 configured as a cylindrical housing. The cylindrical shell window 700 encloses a region 704. The cylindrical bezel 706 is disposed in contact with an outer cylindrical facing surface 708 of the window 702. The apparatus 700 also includes an optical device 710. The apparatus 700 also includes a lens tube 712 disposed within the region 704 for conditioning and directing light to the optical device 710 or from the optical device 710. A cross-section of the device 700 is shown in fig. 7B. The cylindrical bezel 706 includes a seal 714, the seal 714 including a dispenser portion 716 and a wiper 718 configured generally as described above. In operation, window 702 is rotated about axis of rotation 720 to perform cleaning operations similar to those described above in connection with other disclosed embodiments. The seal 714 in this embodiment will have a generally rectangular shape rather than the circular shape of the seal 122 described above for the spherical window 104.

Generally, for the embodiments disclosed herein, the outward facing surface of the window is curved in at least one direction, but not necessarily circularly curved. The non-circular curvature of the outward facing surface of the window will result in a seal that is not necessarily circular in shape. For example, the seal may be oval or even irregularly shaped. The manufacture of an irregular or non-circular seal may be simplified by initially manufacturing a circular seal with a circumference selected to correspond to the desired overall length of the non-circular seal. The material of the circular seal may be selected to be sufficiently compliant to enable the seal to deform into a non-circular or irregular shape. As an example, the seal may be received in a grooved rim having a non-circular or irregular desired shape, with the circular seal conforming within the groove. In many embodiments, the seal has a wiper portion that should be sufficiently uniform to prevent the edges of the wiper portion that allow debris into the reservoir from rising around the perimeter of the seal. Manufacturing a non-circular or irregular seal with sufficient uniformity can be challenging than manufacturing a circular seal.

Referring to fig. 8A and 8B, an embodiment of an apparatus for protecting an optical device from contamination is shown at 800 in a perspective view. The device 800 includes a window 802, the window 802 having an outward facing surface 804 surrounded by a bezel 806, the bezel 806 being attached to a housing 808. The housing 808 encloses an optical device 810 (shown in fig. 8B). The bezel 806 defines a light-passing aperture 812 for transmitting light to and from the optical device 810. Bezel 806 also includes a mounting flange 814 for mounting device 800.

A top cross-sectional view of bezel 806, window 802, and optical device 810 is shown in fig. 8B. Referring to fig. 8B, in this embodiment, the optical device 810 includes an image sensor 816 and a lens tube 818, the lens tube 818 containing a lens 820 for forming an image on the image sensor. The optical device 810 has an optical axis 822 extending perpendicular to the front surface of the image sensor 816. Although in this embodiment, the optical device 810 provides an imaging function, in other embodiments, the optical device may be configured to perform optical functions other than imaging.

Bezel 806 includes a seal 824 extending around the perimeter of the light aperture. In this embodiment, window 802 is configured as a truncated spherical shell. The window 802 is urged into contact with the seal 824 to provide a circular line of contact with the outward facing surface 804 defining the light passing aperture 812. Window 802 is mounted for rotation about an axis of rotation 826, which axis of rotation 826 is, in this embodiment, at an acute angle α relative to optical axis 822. This is in contrast to the embodiments disclosed above, where the relative rotation is about an axis of rotation perpendicular to the optical or imaging axis of the respective optical device. Window 802 includes a ring gear 830 mounted within a perimeter 832 of the housing such that a toothed surface 834 of the gear is directed inwardly relative to the housing. Rotation of the window 802 about the axis of rotation 826 changes a portion of the truncated shell disposed within the light-passing aperture 812. In this embodiment, the window 802 is configured as a hemispherical shell, but in other embodiments, the window 802 may be truncated to provide a spherical shell that is smaller than or larger than a hemisphere.

The apparatus 800 is shown in perspective view with the housing 808 partially cut away in fig. 8C to reveal elements within the housing. Referring to fig. 8C, the apparatus 800 includes a cup 836 and a bushing 838, both of which are integrally disposed within the housing 808. Cup 836 at least partially surrounds optical device 810. The window 802 is received in a forward facing recess of the bushing 838, which facilitates rotation of the window about the axis of rotation 826. Bushing 838 also includes a recess 840 that receives a seal (not shown). Cup 836 is mounted within housing 808 and engages bushing 838, which provides a force urging window 802 into engagement with seal 824. Seal 824 is configured to be compliant enough to deflect slightly under the urging force provided by cup 836, thus ensuring contact between the seal and the window's outward facing surface 804. The seal in the groove 840 seals between the outer circumference of the bushing 838 and the housing.

The apparatus 800 also includes an actuator motor 842. Referring to fig. 8D, the actuator motor 842 is coupled to a sprocket 844, which sprocket 844 engages the toothed surface 834 of the ring gear 830. When the motor 842 is actuated, the sprocket 844 rotates causing the window 802 to rotate within the bushing 838, causing relative rotation between the window 802 and the bezel 806 to move the outward facing surface 804 relative to the bezel. Referring back to fig. 8B, window 802 thus moves relative to bushing 838 and bezel 806, causing outward facing surface 804 to move through light passing aperture 812 defined by seal 824. For the direction of rotation about axis of rotation 826 indicated by arrow 828 in fig. 8B, movement of window 802 will be in a generally downward direction (i.e., into the plane of the page in fig. 8B or in the direction of the arrow shown in fig. 8A).

During movement of the window 802, the seal 824 is configured to dispense the film 848 to the outward facing surface 804 of the window 802 as the outward facing surface 804 of the window 802 is exposed below the seal 824 and into the light passing aperture 812. The film 848 reduces the binding of optical contaminants to the outward facing surface 804 while transmitting light to the optical device 810 or from the optical device 810 through the light passing holes 812. The seal 824 is also configured to remove contaminants entrained in the membrane 848 or adhered to a portion of the outward facing surface 804 that moves out of the light passing aperture 812 during rotation.

In one embodiment, the bushing 838 and the housing 808 together define a reservoir 846 for holding liquid located in front of the housing. The reservoir 846 extends around the perimeter 832 of the window 802 and the seal within the recess 840 of the bushing 838 retains the liquid within the reservoir and prevents the liquid from reaching other components of the apparatus 800, such as the optical device 810. The reservoir is in liquid communication with the seal 824 and during rotation of the window, liquid is dispensed under the seal 824 to form a film 848 on the window facing outer surface 804. In other embodiments, the liquid may include a liquid component and a non-liquid component, or the seal may dispense the non-liquid material by grinding from the seal to form the membrane 848, as described in more detail above.

Still referring to fig. 8B, the angle α between the optical axis 822 and the axis of rotation 826 of the window 802 is selected to pass through a point outside the light-passing aperture 812. This has the effect of causing the exposed portion of the hemispherical surface of window 802 to completely replace the outward facing surface 804 previously exposed to the contaminant during rotation. If the axis of rotation 826 passes through a point within the light passing aperture 812, a small portion of the outward facing surface 804 will not be cleaned or the membrane 848 will not be replenished during rotation.

In one embodiment, seal 824 may be implemented using a polyurethane material having a shore hardness of about 50D that is sufficiently compliant to provide a force for urging window 802 into contact with the seal. In the embodiment of the apparatus 800 shown in fig. 8A-8D, the springs and/or adjustments shown for the embodiments of fig. 6A and 6B are omitted, and the compliant structure for urging the window 802 into contact with the bezel 806 is provided by the compliance of the seal 824.

Additionally, in this embodiment, seal 824 performs both liquid dispensing and wiping functions, and does not include an additional dispenser portion (such as shown at 628 in fig. 6B). However, in some embodiments, additional liquid distribution elements may be implemented for reducing the amount of fluid distributed to the outward facing surface 804. In applications where the outward facing surface 804 of the window 802 is unlikely to be exposed to tough contaminants, such as sap or resin, the reduction of fluid dispensed during each cleaning cycle lengthens the operating time before replenishment of the liquid in the reservoir 846 is required. In some embodiments, the reservoir 846 may contain enough liquid to provide a sufficient cleaning cycle to last the entire operational life of the device 800.

As disclosed above, for a rotational direction about rotational axis 826 indicated by arrow 828 in fig. 8B, movement of window 802 will be in a generally downward direction. This rotational direction has the advantage of causing contaminants 850 entrained in the membrane 848 to move downward within the light passing aperture 812 to accumulate at the lower edge 852 of the seal 824. Gravity then prevents the removed contaminants 852 from being redistributed to the outward facing surface 804.

Hemispherical shell window 802 has the advantage of being manufacturable by conventional optical fabrication techniques, thus potentially reducing the manufacturing cost of the window. In one embodiment, the hemispherical shell may have a diameter of about 40mm and the overall diameter of the shell 808 may be about 60mm. In the embodiment shown in fig. 8A-8D, window 802 has a spherical outer facing surface 854 and a spherical inner facing surface 856. In other embodiments, the inward-facing surface 856 may have an aspherical surface shape that works with the lens 820 to direct light to the optical device 810 or from the optical device 810.

The embodiments disclosed above may be implemented in an optical system that integrates a window protection function and a cleaning function without significantly increasing the overall size of the housing. Compact optical systems are important for some applications where limited space is available, or the systems are intended to be relatively unobtrusive or unobtrusive. The spherical shape of the window allows the wiper and dispenser of the seal to be manufactured on a lathe, which avoids the complex CNC machining that may be required for seal components in other cleaning systems using non-spherical windows or flat windows.

While specific embodiments have been described and illustrated, such embodiments should be considered illustrative only and not limiting of the disclosed embodiments as construed in accordance with the accompanying claims.

Claims

1. An apparatus for protecting an optical device from contamination, the apparatus comprising:

a window disposed between the optical device and a contaminated environment, the window rotatable about an axis of rotation and comprising an outward facing surface curved in at least one direction about the axis of rotation;

a bezel surrounding a portion of the outward facing surface and defining a light-passing aperture for transmitting electromagnetic radiation to or from the optical device, the bezel including a seal extending around a perimeter of the light-passing aperture, the bezel being configured to conform the seal to the outward facing surface when the window and bezel are urged into contact with one another;

an actuator configured to cause relative rotation between the window and the bezel to move the outward facing surface relative to the bezel;

a seal configured to dispense a film to a portion of the outward facing surface that enters the light-passing aperture during the relative rotation, the film operable to reduce binding of optical contaminants within the light-passing aperture to the outward facing surface while transmitting the electromagnetic radiation to or from the optical device through the light-passing aperture; and

Wherein the seal is configured to remove contaminants entrained in the film or adhered to the outward facing surface that move out of a portion of the light passing aperture during the relative rotation.

2. The apparatus of claim 1, wherein the outward facing surface is curved circularly in at least one direction about the axis of rotation.

3. The apparatus of claim 1, wherein the membrane comprises a liquid membrane that remains liquid after being dispensed.

4. The device of claim 3, further comprising a reservoir in liquid communication with the seal, and wherein the seal is configured to dispense a thin film of liquid under the seal during relative rotation between the window and the bezel, and to contain liquid in the reservoir when there is no rotation between the window and the bezel.

5. The apparatus of claim 4, wherein the window and the optical device are enclosed within a housing, and wherein the reservoir is defined within a portion of the housing that extends from the seal in the bezel along a portion of the outward facing surface of the window disposed within the housing to a rear seal that is configured to contain the liquid in the reservoir and prevent the liquid from reaching other portions of the housing.

6. The apparatus of claim 1, wherein the membrane comprises one of:

a liquid material that at least partially solidifies after being dispensed;

a liquid material and a non-liquid material, the liquid material being operable to at least partially evaporate after being dispensed; or (b)

A non-liquid material is dispensed during the relative rotation by grinding from the seal to form the film.

7. The apparatus of claim 1, wherein the seal comprises:

a dispenser portion operable to dispense the film to the portion of the outward facing surface that enters the light aperture during rotation of the window; and

a wiper portion operable to remove the contaminants entrained in the film or adhered to the outward facing surface that move out of the portion of the light passing aperture during rotation of the window.

8. The apparatus of claim 7, wherein the dispenser portion of the seal and the wiper portion of the seal are disposed on opposite sides of the bezel, and rotation of the window is in a direction to move the outward facing surface toward the wiper portion of the seal.

9. The apparatus of claim 7, wherein the wiper portion of the seal comprises a wiper extending around an entire perimeter of the light-passing aperture, and wherein the dispenser portion of the seal comprises a separate seal disposed spaced outwardly from the wiper.

10. The apparatus of claim 1, wherein the optical device and the window are enclosed within a housing, and wherein the bezel comprises a portion of the housing.

11. The device of claim 1, further comprising a compliant structure acting on the window and configured to provide a force for urging the window into contact with the bezel.

12. The apparatus of claim 1, wherein the outward facing surface is circularly curved in the at least one direction about the axis of rotation, and wherein the outward facing surface is further circularly curved in a direction orthogonal to the at least one direction to define a spherical outward facing surface, and wherein the bezel comprises a circular bezel.

13. The apparatus of claim 12, wherein the actuator is configured to cause rotation of the window in a single direction about the axis of rotation, and wherein the rotation causes the seal to remove contaminants from a first portion of the outward facing surface that moves out of the light passing aperture while the dispenser supplements the film on a second portion of the outward facing surface that enters the light passing aperture.

14. The apparatus of claim 12, wherein the window comprises a spherical solid, and wherein the optical device is disposed behind the spherical solid, and wherein the electromagnetic radiation is transmitted to or from the optical device through the light passing aperture and the spherical solid.

15. The apparatus of claim 14, further comprising a volume of immersion liquid contained between a portion of the spherical solid and a first optical element of the optical device, the immersion liquid having an index of refraction that closely matches an index of refraction of the spherical solid.

16. The apparatus of claim 14, wherein the spherical solid comprises a recess disposed within the spherical solid, and wherein the optical device is disposed at least partially within the recess.

17. The apparatus of claim 12, wherein the window includes an inward facing surface curved in the at least one direction about the axis of rotation to define a curved wall between the outward facing surface and the inward facing surface.

18. The apparatus of claim 17, wherein the curved wall extends beyond the light-passing aperture, and wherein the actuator is configured to cause reciprocal rotation of the window about the axis of rotation, wherein rotation in a first direction causes the seal to remove contaminants when a first portion of the outward facing surface moves out of the light-passing aperture, and wherein rotation in a second direction causes the seal to dispense the film to the first portion of the outward facing surface upon re-entry into the light-passing aperture.

19. The apparatus of claim 18, wherein the seal surrounds the light-passing aperture, and wherein the rotation in the first direction causes the seal to dispense the film to a second portion of the outward-facing surface that enters the light-passing aperture, and wherein the rotation in the second direction causes the seal to remove contaminants entrained in the film or adhered to the second portion of the outward-facing surface upon removal of the light-passing aperture.

20. The apparatus of claim 17, wherein the curved wall of the window comprises a spherical shell extending about the axis of rotation to define an enclosed region within the curved wall.

21. The apparatus of claim 20, further comprising at least one optical element disposed within the enclosed region to transmit the electromagnetic radiation to the optical device.

22. The apparatus of claim 21, wherein the optical device is disposed outside of the enclosed region, and wherein the optical element comprises one of:

one or more lenses configured to condition the electromagnetic radiation transmitted to or from the optical device; or (b)

A mirror comprising a reflective surface arranged to redirect the electromagnetic radiation incident on the reflective surface to or from the optical device.

23. The apparatus of claim 21, wherein the optical device is disposed outside of the enclosed region, and wherein the spherical shell comprises at least one opening, and wherein the at least one optical element is mounted on a support structure that extends through the at least one opening to the enclosed region to support the at least one optical element in fixed relation to the optical device.

24. The apparatus of claim 20, further comprising an immersion liquid received within the enclosed region, the immersion liquid having a refractive index substantially matching a refractive index of the window.

25. The apparatus of claim 20, wherein the optical device is disposed within the enclosed region.

26. The apparatus of claim 20, wherein the spherical shell comprises at least one opening, and further comprising an enclosure configured to seal the at least one opening.

27. The apparatus of claim 1, wherein the outward facing surface of the window comprises a cylindrical surface.

28. The apparatus of claim 27, wherein the cylindrical surface comprises a circular cylindrical surface.

29. The apparatus of claim 1, wherein the electromagnetic radiation transmitted to or from the optical device comprises electromagnetic radiation having a wavelength of at least one of:

an ultraviolet wavelength range;

a visible wavelength range;

an infrared wavelength range;

long-wave infrared wavelength range; or (b)

x-ray wavelength range.

30. The apparatus of claim 1, wherein the actuator is configured to cause one of:

a continuous relative rotation;

intermittent relative rotation; or (b)

Relative rotation in one direction followed by relative rotation in the opposite direction.

31. The apparatus of claim 1, wherein:

the window includes a shell including a spherically-facing outer surface and the bezel includes a circular bezel;

the actuator is configured to cause rotation of the window about an axis of rotation aligned at an acute angle with an optical axis of the imaging device to move the outward facing surface through the light aperture.

32. The apparatus of claim 31, wherein the shell comprises one of a spherically-facing inner surface or an aspherically-facing inner surface.

33. The apparatus of claim 32, wherein the optical device is disposed within the housing behind the one of the spherically-facing inner surface or the non-spherically-facing inner surface.

34. The apparatus of claim 31, wherein the axis of rotation passes through a point outside the light passing aperture.

35. The apparatus of claim 31, wherein a rotational direction of the window about the rotational axis is selected to move the window relative to the bezel in a direction such that the contaminant moves downward out of the light aperture.

36. The apparatus of claim 1, further comprising an actuator configured to produce a secondary motion to remove at least some contaminants accumulated at a periphery of the light passing aperture.

37. The apparatus of claim 1, wherein the seal is manufactured in a circular shape, and wherein the seal is mounted within the bezel such that the seal is urged into a non-circular shape.

38. The apparatus of claim 1, wherein the optical device comprises a plurality of optical devices configured to transmit or receive the electromagnetic radiation.