Protecting an optical device during operation using flexible optical film

Abstract

An apparatus for protecting an optical device during operation includes at least one flexible optical film having outer and inner optical surfaces configured to extend across an aperture configured to be used by the optical device; a wiper held in engagement with the outer optical surface and configured to slide and dislodge contaminants when the outer optical surface is moved relative to the wiper; a base coupled to the wiper and engaging the inner optical surface of the film opposite the wiper and configured to hold the film between the base and the wiper while the outer optical surface is moved relative to the wiper wherein the base includes an optical portion in engagement with the inner optical surface of the film opposite the outer optical surface, extending across the aperture; and intermediate optical fluid interposed between the optical portion of the base and the inner optical surface.

Description

[0001] PROTECTING AN OPTICAL DEVICE DURING OPERATION USING FLEXIBLE OPTICAL FILM

[0002] CROSS-REFERENCES

[0003] This application claims the benefit of U.S. provisional patent application no. 63 / 725,394 entitled “PROTECTING AN OPTICAL DEVICE DURING OPERATION USING FLEXIBLE OPTICAL FILM”, filed on November 26, 2024, which is hereby incorporated by reference herein in its entirety. However, such material is only incorporated to the extent that no conflict exists between the incorporated material and the statements and drawings set forth herein. In the event of any such conflict, including any conflict in terminology, the present disclosure is controlling.

[0004] BACKGROUND

[0005] 1. Field

[0006] Embodiments of this disclosure relate to protecting an optical device and more particularly to protecting an optical device using flexible optical film and maintaining a clear field of view during operation.

[0007] 2. Description of Related Art

[0008] Optical devices may have at least one optical surface exposed to the surrounding environment during operation. The optical surface may protect optical components enclosed within a housing. However, the optical surface may accumulate contaminants, such as, during use. In cases where the optical surface is exposed to a harsh environment the optical surface may become too quickly contaminated to rely on periodic manual cleaning. Some known devices for removing contaminants from the optical surface may allow buildup of contaminants, may require excessive maintenance, such as refilling of fluid or unclogging nozzles, may not provide a good seal protecting the optical device from the surrounding environment, may be inefficient, may be costly, may leave excessive contamination in contact with the optical surface and / or may have other drawbacks. SUMMARY

[0009] In accordance with various embodiments, there is provided, there is provided an apparatus for protecting an optical device during operation, the apparatus including: at least one flexible optical film having an outer optical surface and an inner optical surface configured to extend across at least a portion of an aperture configured to be used by the optical device; a wiper held in engagement with the outer optical surface of the at least one flexible optical film, the wiper configured to slide along the outer optical surface and dislodge contaminants from the outer optical surface when the outer optical surface is moved relative to the wiper; a base coupled to the wiper and engaging the inner optical surface of the at least one flexible optical film opposite the wiper, the base configured to hold the at least one flexible optical film between the base and the wiper while the outer optical surface is moved relative to the wiper wherein the base includes an optical portion in engagement with the inner optical surface of the at least one flexible optical film opposite the outer optical surface, the optical portion of the base extending across at least a portion of the aperture configured to be used by the optical device; and optical fluid including an intermediate optical fluid interposed between the optical portion of the base and the inner optical surface of the at least one flexible optical film.

[0010] The optical fluid may include a source optical fluid and the apparatus may include: an optical fluid reservoir holding the source optical fluid, wherein the optical fluid reservoir encloses a source portion of the at least one flexible optical film, such that the source optical fluid is deposited on the inner optical surface of the at least one flexible optical film in the optical fluid reservoir.

[0011] A volume of the source optical fluid held in the optical fluid reservoir may be more than 10 times a volume of the intermediate optical fluid interposed between the optical portion of the base and the inner optical surface of the at least one flexible optical film. The apparatus may include a filter configured to engage with the inner optical surface of the at least one flexible optical film adjacent to an exit of the optical fluid reservoir, the filter configured to capture particles from the source optical fluid as the at least one flexible optical film exits the optical fluid reservoir and is moved toward the optical portion of the base, wherein the filter is configured to allow a portion of the source optical fluid deposited on the inner optical surface to pass

[0012] The filter may be composed of a resiliently deformable porous fluid retaining material.

[0013] The optical fluid may have an index of refraction between about 1.45 and 1.80.

[0014] The intermediate optical fluid may fill a thickness of about 90 nm to 15 urn between the inner optical surface of the at least one flexible optical film and the optical portion of the base.

[0015] The optical fluid may have an index of refraction within 0.1 of an index of refraction of the at least one flexible optical film.

[0016] The optical portion of the base may have an index of refraction within 0.1 an index of refraction of the at least one flexible optical film.

[0017] The flexible optical film may have a thickness between about 30 urn and 200 urn.

[0018] The flexible optical film may be configured to bend to a minimum bend radius of less than about 20 cm.

[0019] The apparatus may include a seal forming a continuous loop on the outer optical surface surrounding the aperture, the seal including the wiper. The apparatus may include at least one actuator coupled between the at least one flexible optical film and the wiper, the at least one actuator configured to move the at least one flexible optical film relative to the wiper. the at least one actuator may be configured to selectively move the at least one flexible optical film relative to the wiper in a first direction and in a second direction opposite to the first direction.

[0020] The apparatus may include at least one processor in communication with the at least one actuator, the at least one processor configured to: periodically cause a cleaning cycle to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film at a first speed in the first direction relative to the wiper for a cleaning distance, the cleaning distance greater than a width of the portion of the aperture across which the at least one flexible optical film extends, such that the cleaning cycle is performed a cleaning number of times; determine that the cleaning number is greater than or equal to a cleaning number threshold, the cleaning number threshold being greater than 2; based on determining that the cleaning number is greater than or equal to the cleaning number threshold, cause a cleaning reset to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film at a second speed in the second direction for a reset distance greater than the cleaning distance.

[0021] The reset distance may be about equal to the cleaning distance times the cleaning number.

[0022] The cleaning number threshold may be greater than 10.

[0023] The second speed may be greater than the first speed.

[0024] The second speed may be more than 10 times the first speed. The at least one processor may be configured to wait for a waiting time between producing the signals for causing the at least one actuator to move the at least one flexible optical film in the first direction, the waiting time between about 1 minute and 8 hours.

[0025] The wiper may be a first wiper and the apparatus may include: a second wiper held in engagement with the outer optical surface of the at least one flexible optical film, the second wiper configured to slide along the outer optical surface and dislodge contaminants from the outer optical surface when the outer optical surface is moved in the second direction relative to the second wiper. The apparatus may include at least one processor in communication with the at least one actuator, the at least one processor configured to: periodically cause a first direction cleaning cycle to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film in the first direction relative to the first wiper for a cleaning distance, the cleaning distance greater than a width of the portion of the aperture across which the at least one flexible optical film extends, such that the first direction cleaning cycle is performed a cleaning number of times; determine that the cleaning number is greater than or equal to a cleaning number threshold, the cleaning number threshold being greater than 2; based on determining that the cleaning number is greater than or equal to the cleaning number threshold, periodically cause a second direction cleaning cycle to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film in the second direction relative to the second wiper for the cleaning distance.

[0026] The base may be a rigid base.

[0027] The base may extend across the aperture. The at least one flexible optical film may include a continuous loop of flexible optical film having an environment facing portion including the outer and inner optical surfaces.

[0028] Other aspects and features of embodiments of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the present disclosure in conjunction with the accompanying figures.

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In drawings which illustrate embodiments of the present disclosure,

[0031] Figure 1 is an isometric view of an optical system including an apparatus for protecting an optical device during operation, according to various embodiments;

[0032] Figure 2 is a sectional isometric view of the system shown in Figure 1, according to various embodiments;

[0033] Figure 3 is a sectional top view of the system shown in Figure 1 , according to various embodiments;

[0034] Figure 4 is an enlarged portion of the sectional top view shown in Figure 3, according to various embodiments; and

[0035] Figure 5 is an enlarged portion of the sectional top view shown in Figure 4, according to various embodiments;

[0036] Figure 6 is an exploded view of a first spool actuator included in the system shown in Figure 1 , according to various embodiments; Figure 7 is a sectional top view of an optical system including an apparatus for protecting an optical device during operation, according to various embodiments;

[0037] Figure 8 is an enlarged portion of the sectional top view shown in Figure 7, according to various embodiments;

[0038] Figure 9 is a schematic representation of a control system that may be included in the system shown in Figure 1 , in accordance with various embodiments;

[0039] Figure 10 is a schematic representation of a controller of the control system shown in Figure 9, in accordance with various embodiments

[0040] Figure 11 is a flowchart depicting blocks of code for directing a controller processor of the controller shown in Figure 10 to perform flexible optical film cleaning in accordance with various embodiments;

[0041] Figure 12 is a flowchart depicting blocks of code for directing a controller processor of the controller shown in Figure 10 to perform flexible optical film cleaning in accordance with various embodiments; and

[0042] Figure 13 is a top view of part of the system shown in Figure 1 , according to various embodiments.

[0043] DETAILED DESCRIPTION

[0044] In accordance with various embodiments, there is shown in Figure 1 , an optical system 100. Referring to Figure 2, a first isometric sectional view of the system 100 shown in Figure 1 taken at the sectioning plane indicated by section lines 2-2 shows inner elements of the system 100 in accordance with various embodiments. Referring to Figure 2, the system 100 includes an optical device 110 and an apparatus 120 for protecting the optical device during operation. In some embodiments, the optical device 110 may include a sensor 112 and a mirror 114. For example, in some embodiments, the sensor 112 may include a LiDAR sensor. In various embodiments, the system 100 may include a housing 208 having an aperture 210 or viewing window configured to be used by the optical device 110 through which light can pass before being reflected by the mirror 114 and detected by the sensor 112. In some embodiments, the mirror 114 may be rotatable such that the mirror facilitates scanning across the aperture 210.

[0045] Referring to Figure 3, a second sectional view of the system 100 shown in Figure 1 taken at the sectioning plane and in the direction indicated by section lines 2-2 shows inner elements of the system 100 from a top view in accordance with various embodiments. Referring to Figure 4, an enlarged view of a portion of Figure 3 is shown.

[0046] Referring to Figures 3 and 4, in various embodiments, the apparatus 120 may include a flexible optical film 200 having an outer optical surface 202 and an inner optical surface 204 configured to extend across at least a portion of the aperture 210. In some embodiments, the flexible optical film 200 may be a thin sheet of transparent flexible material. In some embodiments, the flexible optical film 200 may include flexible transparent material configured to allow light to pass through the flexible optical film 200 for sensing by the optical device 110. For example, in some embodiments, the flexible optical film 200 may include thin, flexible glass, such as, Corning Willow Glass, Schott UTG / Flexinity, or another thin flexible glass, or thin flexible plastic, such as, polycarbonate, acrylic, or another thin flexible plastic. In some embodiments, the flexible optical film 200 may have a thickness of between about 30 urn and about 200 urn. In some embodiments, having a thickness in this range may facilitate reduced volume for rolling storage of the flexible optical film 200 while also keeping the film robust and / or strong. For example, in some embodiments, the flexible optical film 200 may have a thickness of about 50 um. In some embodiments, the flexible optical film 200 may include a material capable of flexing or bending to a minimum bend radius of less than about 20 cm. In some embodiments, the flexible optical film 200 is configured to bend to a minimum bend radius of less than about 20 cm. In some embodiments, having a minimum bend radius of less than about 20 cm may facilitate rolling storage and / or manipulation of the flexible optical film 200. In some embodiments, the flexible optical film 200 may include a material capable of flexing or bending to a minimum bend radius of less than about 50 mm. In some embodiments, the flexible optical film 200 is configured to bend to a minimum bend radius of less than about 50 mm. In some embodiments, the flexible optical film 200 may include a material capable of flexing or bending to a minimum bend radius of less than about 2 mm. In some embodiments, the flexible optical film 200 is configured to bend to a minimum bend radius of less than about 2 mm.

[0047] In some embodiments, the flexible optical film 200 may include a coating on 1 or both sides, including, for example, a scratch resistant coating (which may be particularly helpful in combination with plastic film), and / or an anti-reflective film with performance across target wavelengths of the optical device. In some embodiments, the target wavelengths may be about 380-700 nm for use with a visible light detector, 800-1 OOOnm for use with an infrared detector, such as a typical LiDAR sensor or an infrared camera, or 1400-1600 nm for use with short wave IR detectors, such as InGaAs LiDAR detectors.

[0048] In some embodiments, the flexible optical film 200 may have an index of refraction between about 1.45 and about 1.80 across target wavelengths of the optical device 110, for example. In some embodiments, this range my represent the index of refraction for common optical glasses. In some embodiments, the flexible optical film 200 may have an index of refraction of about 1.5, for example.

[0049] In various embodiments, the flexible optical film 200 being flexible may facilitate it being long and easily moved and / or stored, such as, by rolling or wrapping the film around first and second spools or rollers 304 and 306 as shown in Figure 3. In various embodiments, this may facilitate ease of cleaning and / or replacing or moving the portion of the flexible optical film 200 that extends across the aperture 210. In various embodiments, the flexible optical film 200 being flexible may ease the removal of contaminants from the surface of the flexible optical film.

[0050] Referring still to Figures 3 and 4, in various embodiments, the apparatus 120 may include a wiper 220 held in engagement with the outer optical surface 202 of the flexible optical film 200 (see Figure 4), the wiper 220 configured to slide along the outer optical surface and dislodge contaminants from the outer optical surface when the outer optical surface is moved relative to the wiper. In some embodiments the contaminants may include water, dust, mud, salt, oil, grease, potash, bird droppings, tree sap, and / or another contaminant that may build up during use, for example. In some embodiments, during operation, the flexible optical film 200 may travel relative to the wiper 220 in a first direction shown by the arrow 222 in Figure 3. In some embodiments, the wiper 220 may be in engagement with the outer optical surface 202 through one or more intermediary media, which may include an optical layer medium (“OLM”) or optical fluid deposited on or adhered to the outer optical surface 202. In some embodiments, the OLM may include a material, such as a fluid, which is configured to coat the outer optical surface 202 and prevent or reduce strong adhesion of external contaminants to the outer optical surface 202. In some embodiments, the OLM may provide an average of less than about 0.000196 mm thickness of fluid on the outer optical surface 202. In various embodiments, the optical fluid may be a liquid.

[0051] In various embodiments, the wiper 220 may include a durable flexible material. In various embodiments, the wiper 220 including a durable flexible material may facilitate consistent engagement force relative to the outer optical surface despite inconsistencies in the outer optical surface 202. In some embodiments, the surface roughness of the outer optical surface 202 may be about 1-5 nm RMS (i.e., the RMS value of the deviation from the nominal surface). In various embodiments, this may translate to about 2.82 - 14 nm from highest peak to lowest valley. In some embodiments, for example, the wiper 220 may be composed of high- durometer polyurethane.

[0052] Referring back to Figure 1, in some embodiments, the wiper 220 may be included as a portion of a seal 230 shown in Figure 1. In some embodiments, the seal 230 may form a continuous loop on the outer optical surface 202 surrounding the aperture 210. In some embodiments, the seal 230 may be composed of the same material as the wiper 220 shown in Figure 3, throughout the continuous loop shown in Figure 1. In some embodiments, the seal 230 may have the same cross- sectional shape as the wiper 220 throughout the seal 230. In some embodiments, the seal 230 forming a continuous loop may facilitate sealed separation of an interior of the housing 208 from contaminants in the environment, such as those that may be deposited on the outer optical surface 202. In various embodiments, the continuous loop of durable flexible material may facilitate the seal 230 having a continuous or generally continuous edge in contact with the outer optical surface 202

[0053] Referring to Figure 4, in various embodiments, the apparatus 120 may include a base 240 coupled to the wiper 220 and engaging the inner optical surface 204 of the flexible optical film 200 opposite the wiper 220, the base 240 configured to hold the flexible optical film between the base and the wiper while the outer optical surface 202 of the flexible optical film is moved relative to the wiper. In some embodiments, the base 240 may be rigid. In some embodiments, the base 240 may have a durometer value of equal to or greater than 40A (e.g., pencil eraser hardness). In some embodiments, the base 240 may have a durometer value of about 80D or harder (e.g., in some embodiments, the base 240 may include a metal backing). In various embodiments, the base being rigid may facilitate consistent interaction with the wiper 220 by the outer optical surface 202. In some embodiments, the base 240 and the wiper 220 may both be coupled or mounted to the housing 208 and thus the base and the wiper 220 may be coupled together via the housing 208. In some embodiments, the base 240 holding the flexible optical film 200 between the base 240 and the wiper 220 may facilitate the wiper remaining in engagement with the outer optical surface 202 and dislodging contaminants from the outer optical surface when the outer optical surface is moved relative to the wiper 220. In various embodiments, because of the flexibility of the flexible optical film 200, without the base 240 the flexible optical film 200 may flex away from the wiper 220 such that consistent engagement with the outer optical surface may be lost or reduced when the outer optical surface is moved relative to the wiper 220. In some embodiments, the base 240 holding the flexible optical film 200 between the base and the wiper 220 while the outer optical surface 202 of the flexible optical film 200 is moved relative to the wiper 220 may facilitate decreased stress on the flexible optical film 200 at the wiper 220, which may reduce or eliminate tearing and / or damage to the flexible optical film 200.

[0054] Referring to Figure 3, in some embodiments, the base 240 may include an optical portion 242 in engagement with the inner optical surface 204 of the flexible optical film 200 opposite the outer optical surface 202, the optical portion of the base extending across at least a portion of the aperture 210 configured to be used by the optical device 110. In some embodiments, the optical portion 242 of the base 240 may extend across the aperture 210 as shown in Figure 3. In various embodiments, the base 240 extending across the aperture 210 may facilitate consistent optical characteristics across the aperture 210, such as, by reducing deformation of the flexible optical film 200 across the aperture 210. In various embodiments, the base 240 extending across the aperture 210 may facilitate reduction or prevention of permanent deformation / damage to the flexible optical film 200 in the case of external mechanical force (e.g., if a rock impacts the film, with no support it may either plastically deform (for plastic film) or shatter (for glass film)). In various embodiments, the optical portion 242 of the base 240 may be transparent, such that light may pass through the aperture 210 for sensing by the optical device 110. In some embodiments, the base 240 may be made of a single continuous piece of material and so the base 240 may be transparent throughout.

[0055] In some embodiments, the base 240 may be composed of the same material as is used in the flexible optical film 200. In various embodiments, the base 240 may be thicker than the flexible optical film 200. For example, in some embodiments, the base 240 may have a thickness of between 1 mm and 5 mm. In some embodiments, the base 240 including the optical portion 242 may facilitate supporting the flexible optical film 200 such that the flexible optical film 200 does not flex undesirably and remains in a desired configuration (e.g., generally planar) across the aperture 210. In some embodiments, the base 240 including the optical portion 242 may facilitate increased durability and / or robustness of the flexible optical film 200 by supporting the flexible optical film 200. For example, in some embodiments, the base 240 including the optical portion 242 may reduce damage to the flexible optical film 200 by impact from debris and / or other environmental factors.

[0056] Referring to Figure 5, there is shown an enlarged view of the area shown at 5 in Figure 4. Referring to Figure 5, the flexible optical film 200, including the outer optical surface 202 and the inner optical surface 204, is shown. In some embodiments, the apparatus 120 may include an intermediate optical fluid 250 interposed between the base 240 and the inner optical surface 204 of the flexible optical film 200. In some embodiments, the intermediate optical fluid 250 may be interposed between the optical portion 242 of the base 240 and the inner optical surface 204 of the flexible optical film 200 (see Figures 3 and 5). In various embodiments, the intermediate optical fluid 250 may facilitate reduced refraction and / or reflection between the flexible optical film 200 and the base 240. In various embodiments, the intermediate optical fluid 250 may act as a lubricant for facilitating movement of the flexible optical film 200 relative to the base 240 and to reduce the chances of damage to the flexible optical film 200. In various embodiments, the intermediate optical fluid 250 may be a liquid. In various embodiments, the intermediate optical fluid 250 may be the same optical fluid used as an OLM on the outer optical surface 202 of the flexible optical film. In some embodiments, the intermediate optical fluid 250 may be a silicone oil, such as, for example, DOWSIL™ SH-710. In some embodiments, the intermediate optical fluid 250 may include a specially formulated optical lubricant (which may be silicone based). For example, a silicone-based, ultra-clean index-matching compound designed for photonic applications, such as the optical gel from Nye Lubricants, Inc., may be used as the intermediate optical fluid 250. In various embodiments, the intermediate optical fluid 250 may feature high optical clarity, low volatility and outgassing, and a stable refractive index (e.g., ~1.46 at 589 nm) that helps minimize reflections at interfaces. In various embodiments, the intermediate optical fluid 250 may be formulated to accommodate wide temperature ranges (-65 °C to +200 °C) without yellowing and may support long service life. In various embodiments, the intermediate optical fluid 250 may be one that is also used to fill gaps between optical components (such as fibers, laminations, lenses or LEDs) to bridge refractive indices and thereby improve light transmission / efficiency in devices. In various embodiments, the vapor pressure of the intermediate optical fluid 250 may be equal to that of a lubricant. In some embodiments, the vapor pressure for the intermediate optical fluid 250 may be relatively low, such as between about 0.5Pa-15Pa.

[0057] In various embodiments, the configuration shown in Figure 5 may show the wiper 220 and the flexible optical film 200 at rest. In various embodiments, in operation, when the wiper 220 is moving relative to the flexible optical film 200, the wiper 220 may be spaced apart from the flexible optical film 200, allowing some optical fluid to pass between the wiper and the flexible optical film, due to viscous drag, for example. Accordingly, in various embodiments, not all and in some cases very little optical fluid may be removed by the wiper 220 from the outer optical surface 202 of the flexible optical film 200. In various embodiments, optical fluid may fill the volume shown below the wiper 220 in Figure 5. In various embodiments, the intermediate optical fluid 250 may be transparent across the target wavelengths of the optical device 110. In some embodiments, the intermediate optical fluid 250 may have an index of refraction approximately or about equal to an index of refraction of the flexible optical film 200. In various embodiments, the indices of refraction being approximately equal may reduce reflection and / or improve optical performance between the intermediate optical fluid 250 and the flexible optical film 200. In some embodiments, the closer the indices of refraction, the better. In various embodiments the intermediate optical fluid 250 may have an index of refraction within 0.1 of an index of refraction of the flexible optical film 200. Thus, in various embodiments, the absolute value of the difference between the index of refraction of the intermediate optical fluid 250 and the index of refraction of the flexible optical film 200 may be less than 0.1. In some embodiments, the intermediate optical fluid 250 may have an index of refraction greater than 1 , such as, for example between about 1.45 and about 1.80 across target wavelengths of the optical device 110, for example. In some embodiments, the intermediate optical fluid 250 may have an index of refraction of about 1.5, for example.

[0058] Referring to Figure 3, in some embodiments, the optical portion 242 of the base 240 may have an index of refraction approximately or about equal to an index of refraction of the intermediate optical fluid 250. In various embodiments, the indices of refraction being approximately equal may reduce reflection and / or improve optical performance between the base 240 and intermediate optical fluid 250. In some embodiments, the closer the indices of refraction, the better. In various embodiments the optical portion 242 of the base 240 may have an index of refraction within 0.1 of an index of refraction of the intermediate optical fluid 250. Thus, in various embodiments, the absolute value of the difference between the index of refraction of the optical portion 242 of the base 240 and the index of refraction of the intermediate optical fluid 250 may be less than 0.1. In some embodiments, the base 240 may have an index of refraction between about 1.45 and about 1.80 across target wavelengths of the optical device 110, for example. In some embodiments, the base 240 may have an index of refraction of about 1.5, for example.

[0059] Referring to Figure 3, in some embodiments, the optical portion 242 of the base 240 may have an index of refraction approximately or about equal to an index of refraction of the flexible optical film 200. In various embodiments, the indices of refraction being approximately equal may reduce reflection and / or improve optical performance between the base 240 and the flexible optical film 200. In some embodiments, the closer the indices of refraction, the better. In various embodiments the optical portion 242 of the base 240 may have an index of refraction within 0.1 of an index of refraction of the flexible optical film 200. Thus, in various embodiments, the absolute value of the difference between the index of refraction of the optical portion 242 of the base 240 and the index of refraction of the flexible optical film 200 may be less than 0.1.

[0060] In some embodiments, matching indices of refraction of the intermediate optical fluid 250, the flexible optical film 200, and / or the base 240 may facilitate reduced distortion of light and / or improved imaging using the system 100.

[0061] In some embodiments, the intermediate optical fluid 250 may fill a thickness of about 90 nm to 15 urn between the inner optical surface 204 of the flexible optical film 200 and the optical portion 242 of the base 240. In various embodiments, a thickness of the intermediate optical fluid 250 in this range may facilitate lubricated travel of the flexible optical film 200 relative to the base 240 while keeping optical distortion low. In various embodiments, this thickness range may be similar to a typical thickness used in mechanical bushing applications if considering the friction aspect during movement. In various embodiments, thinner than this range may allow excessive wear and high friction loads, while thicker than this range may be unnecessary for lubrication. In some embodiments, the thickness of the intermediate optical fluid 250 may be determined by various factors, including the geometry of the system 100. In some embodiments, the geometry and configuration of the seal 230 where the flexible optical film 200 film travels below the seal 230 may control the thickness of the intermediate fluid 250. In some embodiments, the thickness may depend on viscosity of the optical fluid, speed of travel of the flexible optical film 200, contact length of the seal 230 on the flexible optical film 200, pressure applied by the seal 230 on the flexible optical film 200, and / or line load, wherein line load is a load per unit length of the seal (e.g., 2000 N / m). In some embodiments, viscosity of the optical fluid may be about 60cP, speed may be about 100mm / s, line load may be about 2N / mm and 1mm wide contact and thickness of the intermediate optical fluid 250 may be about 3um, for example.

[0062] In some embodiments, the base 240 including the optical portion 242 across the aperture 210 shown in Figure 3 may facilitate consistent thickness of the intermediate optical fluid 250 across the aperture 210, which may facilitate reduced optical distortion of light and / or improved imaging using the system 100.

[0063] In some embodiments, the apparatus 120 may include at least one actuator coupled between the flexible optical film 200 and the wiper 220, the at least one actuator configured to move the flexible optical film 200 relative to the wiper 220. In some embodiments, the at least one actuator may include a first spool actuator 264 including the first spool 304, as shown in Figures 3 and 4.

[0064] Referring to Figure 6, an exploded isometric view of the first spool actuator 264 according to various embodiments, is shown. In various embodiments, the first spool actuator 264 includes a motor 266 mounted or coupled to the housing 208 (shown in Figures 1 to 4) and configured to actuate or drive the first spool 304 relative to the housing, the first spool acting as a first actuated or driven spool. In various embodiments, the motor 266 may be disposed internally within the first spool 304. In some embodiments, the first spool actuator may include a bearing 268 coupled between the first spool 304 and the housing 208 (shown in Figures 1 to 4) and configured to facilitate the motor 266 remaining fixed relative to the housing while the first spool 304 rotates relative to the housing 208 and the motor 266

[0065] Referring to Figures 3 and 4, in various embodiments, the flexible optical film 200 may be coupled to the first spool 304 such that driving the first spool 304 in a counter clockwise direction in the view shown in Figure 3 may cause the flexible optical film 200 to travel in the first direction shown by the arrow 222. In various embodiments, the flexible optical film 200 may be coupled to the second spool 306, which may be coupled to the flexible optical film 200 to hold a rolled up source portion of the flexible optical film. In various embodiments, driving of the first spool 304 in a counter clockwise direction in the view shown in Figure 3 may cause the flexible optical film 200 to pull the second spool 306 such that the second spool 306 rotates in a counter clockwise direction and provides further flexible optical film.

[0066] In various embodiments, in operation, the first spool 304 may rotate to cause the flexible optical film 200 to travel in the first direction shown by the arrow 222 relative to the wiper 220. In various embodiments, as the flexible optical film 200 moves past the wiper 220, a wiper edge of the wiper 220 may clear contaminants from the outer optical surface 202. In various embodiments, the first spool 304 may include a high-friction surface and, when actuated or driven, the first spool 304 may provide sufficient tension to move the flexible optical film. In some embodiments, the flexible optical film may include notches and the first spool 304 may include matching protrusions to lock and pull the flexible optical film. In some embodiments, the first spool 304 may include a clamp having high friction clamping surfaces, such as, including high friction rubber texture,

[0067] In some embodiments, a cleaning “cycle” may involve pulling the flexible optical film 200 fully in the first direction shown by the arrow 222 and stopping. In some embodiments, the first spool actuator 264 may be configured to cause a cleaning cycle to be executed. In some embodiments, the system 100 may be designed for easy replacement of a roll of flexible optical film on the second spool 306.

[0068] Referring to Figure 3, in some embodiments, the apparatus 120 may include a first optical fluid reservoir 340 configured to hold source optical fluid, such as including the OLM and the intermediate optical fluid 250 described herein. In some embodiments, the first optical fluid reservoir 340 may enclose or be in fluid communication with a source portion of the flexible optical film 200, such that the optical fluid held in the first optical fluid reservoir 340 is deposited on and / or adheres to the inner optical surface 204 of the flexible optical film 200 in the first optical fluid reservoir 340. In various embodiments, use of the first optical fluid reservoir 340 may facilitate ease of deposition of the optical fluid onto the flexible optical film 200.

[0069] In some embodiments, the first optical fluid reservoir 340 may enclose or be in fluid communication with the source portion of the flexible optical film 200, such that the optical fluid held in the first optical fluid reservoir 340 is deposited on and / or adheres to the outer optical surface 202 of the flexible optical film 200 in the first optical fluid reservoir 340. In some embodiments, the first optical fluid reservoir 340 may enclose or be in fluid communication with the source portion of the flexible optical film 200, such that the optical fluid held in the first optical fluid reservoir 340 is deposited on and / or adheres to both the inner and outer optical surfaces 204 and 202 of the flexible optical film 200 in the first optical fluid reservoir 340. In various embodiments, the source portion of the flexible optical film 200 may be a portion of flexible optical film 200 that will be moved across the aperture 210.

[0070] In some embodiments, as the flexible optical film 200 travels in the first direction shown by the arrow 222 shown in Figure 3, optical fluid deposited on and / or adjacent to the inner optical surface 204 may be added to and / or included in the intermediate optical fluid 250 shown in Figure 5. In various embodiments, the first optical fluid reservoir 340 may be configured to hold enough of the optical fluid such that the optical fluid is readily deposited on the inner and / or outer optical surfaces 204 and 202. In some embodiments, a volume of the source optical fluid held in the first optical fluid reservoir 340 may be more than 10 times a volume of the intermediate optical fluid 250 interposed between the optical portion 242 of the base 240 and the inner optical surface 204 of the flexible optical film. In various embodiments, this amount of fluid may facilitate optical fluid being readily deposited on the inner and / or outer optical surfaces 204 and 202. In various embodiments, some optical fluid may be lost throughout operation (not all of the optical fluid deposited on the outer optical surface 202 is recovered) and although the first optical fluid reservoir 340 may be replenished (e.g., from a second optical fluid reservoir 380 in fluid communication with the first optical fluid reservoir 340, for example), this is not instantaneous and so having a sufficient buffer of at least 10 times the volume of the intermediate optical fluid 250 may be advantageous.

[0071] In some embodiments, the first optical fluid reservoir 340 may hold or enclose the second spool 306, the second spool 306 holding the source portion of the flexible optical film 200.

[0072] Referring still to Figure 3, in some embodiments, the apparatus 120 may include first and second filters 360 and 362 configured to engage with the flexible optical film 200 as the flexible optical film exits the first optical fluid reservoir 340. In some embodiments, the first filter may be configured to capture or block small and / or microscopic particles which may pass below the seal 230, preventing optical fluid held in the first optical fluid reservoir 340 from becoming contaminated. In various embodiments, contamination may result in the optical fluid losing functionality, such as, for example, losing its transparency or the contaminants becoming trapped between the flexible optical film 200 and the base 240 causing scratching.

[0073] In some embodiments, the second filter 362 may be configured to engage with the inner optical surface 204 of the flexible optical film 200 adjacent to an exit of the first optical fluid reservoir 340, the second filter 362 configured to capture particles from the source optical fluid as the flexible optical film 200 exits the first optical fluid reservoir 340 and is moved toward the optical portion 242 of the base 240, wherein the second filter 362 is configured to allow a portion of the source optical fluid deposited on the inner optical surface 204 to pass. In some embodiments, the second filter 362 may be configured to capture or block small and / or microscopic particles contained in the source optical fluid held in the first optical fluid reservoir 340 to prevent or reduce such particles from being included in the intermediate optical fluid 250 shown in Figure 5. In various embodiments, this may reduce and / or prevent contaminants becoming trapped between the flexible optical film 200 and the base 240 and causing scratching. In some embodiments, the first and second filters 360 and 362 may be composed of a resiliently deformable porous fluid retaining material. In various embodiments, the filter being composed of a resiliently deformable porous fluid retaining material may facilitate capture of particles while allowing some source optical fluid deposited on the inner optical surface to pass by. In some embodiments, the first and second filters 360 and 362 may be composed of a material having minimal particulate shedding. For example, in some embodiments, the first and second filters 360 and 362 may include a sponge, fabric, felt, and / or another material that is a resiliently deformable porous fluid retaining material.

[0074] Referring to Figure 3, in some embodiments, the seal 230 may include a portion adjacent to the first filter 360, which may act as a controlled applicator, when the flexible optical film 200 travels in the first direction, allowing a thin layer of optical fluid, deposited on the flexible optical film 200 from the first optical fluid reservoir 340, to remain on the outer optical surface 202 as the flexible optical film passes by the portion of the seal 230 acting as an applicator. Referring to Figure 5, the thin layer of optical fluid is shown at 370. In various embodiments, the thin layer of optical fluid may act as the OLM. Referring back to Figure 3, in some embodiments, the at least one actuator of the apparatus 120 may include a second spool actuator 368 including the second spool 306 and configured to selectively drive the second spool 306 clockwise to move the flexible optical film in a second direction opposite to the arrow 222 shown in Figure 3. In some embodiments, the second spool actuator 368 may include elements generally similar to those included in the first spool actuator 264 shown in Figure 6 and described herein. In some embodiments, a cleaning cycle may involve pulling the flexible optical film 200 fully in the first direction shown by the arrow 222 and then the apparatus 120 may be configured to reset by pulling the film fully back in the second direction opposite to that shown by the arrow 222. In some embodiments, the flexible optical film 200 may have a length of more than twice a width of the aperture 210, the width of the aperture measured along the length of the flexible optical film. In some embodiments, the width of the aperture 210 may be about 100 mm and the flexible optical film 200 may have a length of about 300 mm.

[0075] In some embodiments, the lubrication provided by the intermediate optical fluid 250 disposed between the inner optical surface 204 and the base 400 may facilitate reuse of the flexible optical film 200 without scratching of the flexible optical film such that travel of the flexible optical film 200 in the first and second directions for cleaning is feasible and / or desirable. In various embodiments, the ability to move the flexible optical film 200 in the first and second directions may facilitate reuse of areas of the flexible optical film 200 for protecting the optical device and / or improved efficiency in cleaning of the flexible optical film 200.

[0076] In various embodiments, the first spool actuator 264 and the second spool actuator 368 may be configured to cause the cleaning cycle and reset to be executed periodically. For example, in some embodiments, the first spool actuator 264 and the second spool actuator 368 may be configured to cause the cleaning cycle and reset to be executed every one minute to 8 hours. In various embodiments, the first spool actuator 264 and / or the second spool actuator may include a processor circuit such as a microcontroller and / or a timer circuit configured to cause the cleaning cycle to be executed every one minute to 8 hours. In various embodiments, this waiting period may facilitate use of the system 100 in environments where continuous cleaning is not required, but relatively high frequency cleaning is desirable.

[0077] In some embodiments, the apparatus 120 may be generally symmetric across the aperture 210 such that the apparatus 120 functions generally similarly whether driving the flexible optical film 200 in the first direction of the arrow 222 shown in Figure 3 or in the second direction opposite to that shown by the arrow 222. In various embodiments, when the flexible optical film 200 is moving in the second direction opposite to that shown by the arrow 222, the portion of the seal 230 adjacent to the first and second filters 360 and 362, may act as a wiper generally similarly to the wiper 220, and the wiper 220 may act as a controlled applicator. Referring to Figure 3, the apparatus 120 may include a second optical fluid reservoir 380 and third and fourth filters 390 and 392, the second optical fluid reservoir 380 and third and fourth filters 390 and 392 having generally similar functionality to the first optical fluid reservoir 340 and the first and second filters 360 and 362. In some embodiments, the first and second optical fluid reservoirs 340 and 380 may be in fluid communication with one another such that fluid from the second optical fluid reservoir 380 can replenish fluid from the first optical fluid reservoir 340 and / or vice versa.

[0078] Various embodiments

[0079] In accordance with various embodiments, there is shown in Figure 7, a sectional view of an apparatus 500 for protecting an optical device during operation. In various embodiments, the apparatus 500 may be included in a system generally similar to the system 100 described herein having regard to Figures 1 to 6. Referring to Figure 8, a portion of the apparatus 500 is shown enlarged, according to various embodiments. In various embodiments, the apparatus 500 shown in Figures 7 and 8 may provide functionality generally similar to that provided by the apparatus 120 shown in Figures 1 to 6 and described herein. However in various embodiments, the apparatus 500 may differ from the apparatus 120 at least in that a flexible optical film used in the apparatus 500 may form a continuous loop.

[0080] Referring to Figures 7 and 8, the apparatus 500 includes a flexible optical film 600. Referring to Figure 8, in various embodiments, the flexible optical film 600 may include an outer optical surface 602 and an inner optical surface 604 configured to extend across at least a portion of an aperture 610 used by an optical device. In some embodiments, the apparatus 500 may include a housing 608 defining the aperture 610. In some embodiments, the flexible optical film 600 may have generally similar properties to the flexible optical film 200 shown in Figures 1 to 5 and described herein, except that the flexible optical film 600 may form a continuous loop as described further below.

[0081] In various embodiments, the apparatus 500 includes a wiper 620 held in engagement with the outer optical surface 602 of the flexible optical film 600, the wiper 620 configured to slide along the outer optical surface 602 and dislodge contaminants from the outer optical surface 602 when the outer optical surface is moved relative to the wiper 620. In some embodiments, the wiper 620 may be generally similar to the wiper 220 shown in Figures 1 to 5 and described herein.

[0082] In various embodiments, the apparatus 500 may include a base 640 coupled to the wiper 620 and engaging the inner optical surface 604 of the flexible optical film opposite the wiper, the base configured to hold the flexible optical film 600 between the base 640 and the wiper 620 while the outer optical surface 602 is moved relative to the wiper 620.

[0083] Referring to Figure 7, in some embodiments, the flexible optical film 600 may be a continuous loop of flexible optical film. Referring to Figure 7, in the configuration shown, the flexible optical film 600 may include an environment facing portion 800 including the outer and inner optical surfaces 602 and 604, the environment facing portion 800 extending across the aperture 610 as shown in Figure 7. Referring to Figure 7, in the configuration shown, the flexible optical film 600 may include a first optical fluid engaging portion 802, disposed within a first optical fluid reservoir 740. Referring to Figure 7, in the configuration shown, the flexible optical film 600 may include an internal facing portion 804, which in the embodiment shown in Figure 7 extends across the aperture 610 such that the base 640 is disposed between the environment facing portion 800 of the flexible optical film 600 and the internal facing portion 804 of the flexible optical film 600. Referring to Figure 7, in the configuration shown, the flexible optical film 600 may include a second optical fluid engaging portion 806 disposed within a second optical fluid reservoir 780 between the internal facing portion 804 and the environment facing portion 800.

[0084] In various embodiments, the apparatus 500 includes optical fluid including an intermediate optical fluid interposed between an optical portion 642 of the base 640 and the inner optical surface 604 of the flexible optical film 200, generally similar to the intermediate optical fluid as described herein having regard to Figures 3, 4, and 5.

[0085] In various embodiments, in operation, a first spool 704 may be actuated or driven by a first spool actuator generally similar to the first spool actuator 264 described having regard to Figures 4 and 6 and the first spool 704 may pull the flexible optical film 600 such that the environment facing portion 800 of the flexible optical film 600 travels in the direction shown by the arrow 622 in Figure 7 and the internal facing portion of the flexible optical film 600 travels in the opposite direction. In various embodiments, because the flexible optical film 600 forms a continuous loop, the film may be actuated or driven as such indefinitely.

[0086] In various embodiments, the flexible optical film 600 forming the continuous loop may facilitate improved cleaning of the flexible optical film. For example, in some embodiments, being able to actuate or drive the flexible optical film 600 in one direction only for cleaning may facilitate reduced smearing, contamination build-up being always on a single edge (i.e. , at the wiper 620), and / or orienting the system such that the wiper 620 is lower than the seal near the first optical fluid reservoir 740 to facilitate reduced build-up by taking advantage of gravity.

[0087] Referring to Figure 7, in various embodiments, the apparatus 500 may include a first rear seal 840, which may be configured to seal the first optical fluid reservoir 740 to reduce loss of fluid from the reservoir as the flexible optical film transitions from the second optical fluid engaging portion 806 to the internal facing portion 804. In some embodiments, the first and second optical fluid reservoirs 740 and 780 may be in fluid communication with one another. In various embodiments, the apparatus 500 may include a second rear seal 842, which may be configured to be configured to seal the second optical fluid reservoir 780 to reduce loss of fluid from the reservoir. In some embodiments, the first and second rear seals 840 and 842 may be portions of a single continuous seal.

[0088] In some embodiments, an apparatus generally similar to the apparatus 120 shown in Figure 2 or the apparatus 500 shown in Figure 7 may include a plurality of flexible optical films, which may be layered and together and may have an outer optical surface and an inner optical surface configured to extend across at least a portion of an aperture of an optical device. For example, in some embodiments, an apparatus generally similar to the apparatus 500 shown in Figure 7 may be configured such that an internal facing portion of a flexible optical film is interposed between an environment facing portion of the flexible optical film and a base. In some embodiments, a plurality of flexible optical films layered together may act as a flexible optical film generally as described herein with reference to other embodiments described herein.

[0089] In some embodiments, an optical device generally similar to the optical device 110 shown in Figure 2 and described herein may include additional or alternative optical devices, such as, a camera, a stereo camera, a time of flight camera, a light source, radar detector a photovoltaic or solar cell, or another optical device. In some embodiments, a system generally similar to the system 100 shown in Figure 1 to 6 or an apparatus generally similar to the apparatus 500 shown in Figure 7 may include a base that does not extend across the aperture 210. For example, in some embodiments, the system may include a first base adjacent to a wiper similar to the wiper 220 shown in Figure 3 that ends near the wiper and does not extend across the aperture. In some embodiments, the system or apparatus may include a second base adjacent to a seal similar to the seal 230 that does not extend across an aperture similar to the aperture 210. In some embodiments, the first and second bases may be portions of a single continuous base.

[0090] In some embodiments, a system generally similar to the system 100 shown in Figure 1 to 6 or an apparatus generally similar to the apparatus 500 shown in Figure 7 may include a base having a curvature, such as a circular curvature, which may optimize performance of an optical sensor used in the system or apparatus.

[0091] In some embodiments, a system generally similar to the system 100 shown in Figure 1 to 6 or an apparatus generally similar to the apparatus 500 shown in Figure 7 may include a base having more than one different radius curvature, the radius of curvature changing upstream (relative to movement of the flexible optical film) of a wiper similar to the wiper 220. In some embodiments, the changing curvature may facilitate breaking of adhesion of cured contaminants (ice, salt, etc) to the flexible optical film.

[0092] In some embodiments, a wiper for use in a system generally similar to the system 100 shown in Figure 1 may include a rigid material, urged into contact with the outer optical surface 202 by an elastic or compliant material such as a spring, rubber, or another elastic or compliant material. In some embodiments, the flexible optical film, optical fluid, and / or rigid base may be opaque or "black" in non-target wavelengths (e.g., in the visible spectrum), but highly transparent in the target wavelengths (e.g., at infrared wavelengths).

[0093] Referring to Figure 9, there is shown a schematic representation of a control system 1000 that may be included in the system 100 in accordance with various embodiments. In various embodiments, the control system 1000 includes the first spool actuator 264, the second spool actuator 368, and a controller 1002 in communication with the first and second spool actuators 264 and 368. In various embodiments, the controller 1002 may be configured to control the first and second spool actuators 264 and 368 to cause cleaning of the flexible optical film to be performed.

[0094] For example, in some embodiments, the controller 1002 may be configured to produce signals for causing a cleaning cycle involving pulling the flexible optical film 200 fully in the first direction shown by the arrow 222 and then a reset involving pulling the film fully back in the second direction opposite to that shown by the arrow 222 as described above. However, in other embodiments, the controller 1002 may cause other cleaning processes to be performed.

[0095] In some embodiments, the system 100 shown in Figures 1 to 6 may include a flexible optical film that is much longer than a width of the aperture 210, such that the flexible optical film may be moved in the direction shown by the arrow 222 for more than the width of an aperture similar to the aperture 210 and additional flexible optical film may still be available from the second spool 306. In some embodiments, for example, the flexible optical film 200 may have a length of about 6000 mm and the width of the aperture 210 may be about 100 mm.

[0096] In such embodiments, a cleaning cycle may involve driving flexible optical film in the same direction for a cleaning distance, which may be greater than the width of an aperture and an actuator may be configured to periodically perform a cleaning cycle during use. In some embodiments, upon completion of a set number of cleaning cycles (e.g. , 10 to 50, or more, depending on a length of the flexible optical film), the flexible optical film may be actuated or driven in the opposite direction for the same number of cleaning cycles (e.g., 10 to 50, or more). In various embodiments, this may have the advantage of minimizing smearing (i.e. , smearing may only exist for the first 1-2 cycles after changing directions). In various embodiments, this variant may have an advantage of spreading any wear of the film across a larger amount of film, potentially giving longer lifetimes. In some embodiments, an amount of film pulled for each cleaning cycle may be at least the width of the aperture, but possibly more (which may reduce or minimize left over smearing).

[0097] Referring to Figure 10, a schematic view of the controller 1002 of the control system 1000 shown in Figure 9 according to various embodiments is shown. Referring to Figure 10, the controller 1002 includes a processor circuit including a controller processor 1200 and a program memory 1202, a storage memory 1204, and an input / output (I / O) interface 1212, all of which are in communication with the controller processor 1200. In various embodiments, the controller processor 1200 may include one or more processing units, such as for example, a central processing unit (CPU), a graphics processing unit (GPU), and / or a field programmable gate array (FPGA). In some embodiments, any or all of the functionality of the controller 1002 described herein may be implemented using one or more FPGAs.

[0098] The I / O interface 1212 includes an interface 1220 for communicating with the first spool actuator 264 shown in Figure 9 and an interface 1222 for communicating with the second spool actuator 368 shown in Figure 9. In some embodiments, each of the interfaces may include one or more interfaces and / or some or all of the interfaces may be implemented as combined interfaces or a single interface. In some embodiments, where a device is described herein as receiving or sending information, it may be understood that the device receives signals representing the information via an interface of the device or produces signals representing the information and transmits the signals to the other device via an interface of the device.

[0099] Processor-executable program codes for directing the controller processor 1200 to carry out various functions are stored in the program memory 1202. Referring to Figure 5, the program memory 1202 includes a block of codes 1290 for directing the controller processor 1200 to perform flexible optical film cleaning functions. In this specification, it may be stated that certain encoded entities such as applications or modules perform certain functions. Herein, when an application, module or encoded entity is described as taking an action, as part of, for example, a function or a method, it will be understood that at least one processor (e.g., the controller processor 1200) is directed to take the action by way of programmable codes or processor-executable codes or instructions defining or forming part of the application.

[0100] The storage memory 1204 includes a plurality of storage locations including location 1240 for storing cleaning cycle counter data and location 1242 for storing cleaning number threshold data. In various embodiments, the plurality of storage locations may be stored in a database in the storage memory 1204.

[0101] In various embodiments, the block of codes 1290 may be integrated into a single block of codes or portions of the block of codes 1290 may include one or more blocks of code stored in one or more separate locations in the program memory 1202. In various embodiments, any or all of the locations 1240-1242 may be integrated and / or each may include one or more separate locations in the storage memory 1204. Each of the program memory 1202 and storage memory 1204 may be implemented as one or more storage devices including random access memory (RAM), a hard disk drive (HDD), a solid-state drive (SSD), a network drive, flash memory, a memory stick or card, any other form of non-transitory computer- readable memory or storage medium, and / or a combination thereof. In some embodiments, the program memory 1202, the storage memory 1204, and / or any portion thereof may be included in a device separate from the controller 1002 and in communication with the controller 1002 via the I / O interface 1212, for example. In some embodiments, the functionality of the controller processor 1200 and / or the controller 1002 as described herein may be implemented using a plurality of processors and / or a plurality of devices.

[0102] As discussed above, in various embodiments, the controller 1002 shown in Figure 10 may be configured to perform flexible optical film cleaning functions. Referring to Figure 11, a flowchart depicting blocks of code for directing the controller processor 1200 shown in Figure 10 to perform flexible optical film cleaning in accordance with various embodiments is shown generally at 1400. In various embodiments, the blocks of code included in the flowchart 1400 may be encoded in the block of codes 1290 of the program memory 1202 shown in Figure 10.

[0103] Referring to Figure 11 , the flowchart 1400 begins with block 1402 which directs the controller processor 1200 to periodically cause a cleaning cycle to be performed. In various embodiments, block 1402 may direct the controller processor 1200 to periodically produce signals for causing at least one actuator to move the flexible optical film 200 shown in Figure 3 at a first speed in a first direction relative to the wiper 220 for a cleaning distance, the cleaning distance greater than a width of the portion of the aperture across which the flexible optical film 200 extends, such that the cleaning cycle is performed a cleaning number of times. In various embodiments, block 1402 may direct the controller processor 1200 to transmit signals to the first spool actuator 264 via the interface 1220 of the I / O interface 1212 for causing the first spool actuator 264 to drive the first spool 304 and cause the flexible optical film 200 to travel at a first speed in the first direction shown by the arrow 222 in Figure 3 for a cleaning distance greater than the width of the aperture 210 shown in Figure 3. In some embodiments, for example, the cleaning distance may be about 120 mm if the width of the aperture is about 100 mm.

[0104] In some embodiments, the first speed may be about 5 mm / s to 100 mm / s, for example. In some embodiments, the first speed may be about 20 mm / s, for example. In various embodiments, the first speed may be less than 100 mm / s because it may be constrained by tension on the flexible optical film 200 and / or load on the first spool actuator 264. In various embodiments, the first speed may be greater than 5 mm / s because it may be constrained by what is practical for cleaning using periodic cleaning cycles (e.g., if it takes too long it may not be useful). In some embodiments, a speed of the flexible optical film 200 may be lower (e.g., around 1mm / s) if the flexible optical film 200 is driven continuously without stopping.

[0105] In some embodiments, block 1402 may direct the controller processor 1200 to wait for a waiting time between producing the signals for causing the at least one actuator to move the flexible optical film 200 in the first direction. In some embodiments, the waiting time may be between about 1 minute and 8 hours. In various embodiments, this waiting time may facilitate use of the system 100 in environments where continuous cleaning is not required, but relatively high frequency cleaning is desirable. In some embodiments, the waiting time may have previously been set by a user of the control system 1000 and may be determined based on how quickly the flexible optical film 200 gets dirty. In some embodiments, the waiting time may be about an hour. In some embodiments, the waiting time may be 0 and cleaning may be continuous (e.g., for heavy rain conditions or monitoring a process that creates continuous splash back).

[0106] In various embodiments, block 1402 may direct the controller processor 300 to increment a cleaning cycle counter stored in the location 1240 of the storage memory 1204 shown in Figure 10 every time that a cleaning cycle is performed wherein the first spool actuator 264 moves the flexible optical film 200 the cleaning distance. In various embodiments, the cleaning cycle counter may store a cleaning number representing a count of times that a cleaning cycle has been performed by execution of block 1402. In various embodiments, the cleaning cycle counter may have been initialized to zero prior to a first execution of block 1402.

[0107] In various embodiments, after block 1402 has been executed or concurrent with a continuing execution of block 1402 wherein the controller processor 1200 periodically causes cleaning cycles to be performed between waiting times and increments the cleaning cycle counter, block 1404 may be executed.

[0108] Block 1404 directs the controller processor 1200 to determine whether the cleaning number is greater than or equal to a cleaning number threshold, the cleaning number threshold being greater than 2. Accordingly, block 1404 may direct the controller processor 1200 to determine whether the cleaning cycle has been performed greater than or equal to a cleaning number threshold of times, the cleaning number threshold being greater than 2. In various embodiments the cleaning number threshold being greater than 2 may facilitate use of a longer flexible optical film and increase longevity of the flexible optical film. In some embodiments, the cleaning number threshold may have been previously set by a user of the control system 1000 shown in Figure 9. In various embodiments, a representation of the cleaning number threshold may be stored in the location 1242 of the storage memory 1204. In some embodiments, the cleaning number threshold may be greater than 10. In some embodiments, the cleaning number threshold being greater than 10 may facilitate reduced time resetting and / or increased longevity of use of the flexible optical film 200. In some embodiments, the cleaning number threshold may be between 10 and 50 for example. In some embodiments, the cleaning number threshold may be 30 for example. Referring to Figure 11, block 1404 may direct the controller processor 300 to read the cleaning cycle counter from the location 1240 of the storage memory 1204 shown in Figure 10 and the cleaning number threshold from the location 1242 of the storage memory 1204. Block 1404 may direct the controller processor 300 to determine whether the cleaning cycle counter is greater than or equal to the cleaning number threshold. If at block 1404, the controller processor 300 determines that the cleaning cycle counter is greater than or equal to the cleaning number threshold, then block 1404 may direct the controller processor 1200 to proceed to block 1406. If at block 1404, the controller processor 1200 determines that the cleaning cycle counter is less than the cleaning number threshold, then block 1404 may direct the controller processor 1200 to return to block 1402 for continued execution of block 1402.

[0109] Referring to Figure 11, block 1406 directs the controller processor 1200 to cause a cleaning reset to be performed. In some embodiments, block 1406 may direct the controller processor 1200 to produce signals for causing the at least one actuator to move the flexible optical film 200 at a second speed in a second direction opposite the first direction for a reset distance greater than the cleaning distance. In various embodiments, this may put the flexible optical film 200 back into a position where continued use of the optical device 110 and / or further cleaning cycles may be performed. In some embodiments, block 1406 may direct the controller processor 1200 to transmit signals to the second spool actuator 368 shown in Figure 9 via the interface 1222 of the I / O interface 1212 shown in Figure 10 for causing the second spool actuator 368 to drive the second spool 306 and cause the flexible optical film 200 to travel at a second speed in the second direction opposite to the direction shown by the arrow 222 in Figure 3 for a reset distance greater than the cleaning distance. In some embodiments, for example, the reset distance may be equal to the cleaning distance times the cleaning number, such that after execution of block 1406, the flexible optical film 200 is in the same position it was before execution of block 1402. In some embodiments, the cleaning cycle counter may represent the cleaning number and so block 1406 may direct the controller processor 1200 to read the cleaning cycle counter from the location 1240 of the storage memory 1204 shown in Figure 10 and to transmit signals to the second spool actuator 368 shown in Figure 9 based at least in part on the cleaning cycle counter value.

[0110] In some embodiments, using the reset as described having regard to the flowchart 1400 shown in Figure 11 may facilitate, in the case that the flexible optical film 200 travels vertically downward from top to bottom in the first direction, avoiding or reducing issues that may arise from cleaning by moving the flexible optical film in the second direction, such as, for example, drips that may arise from pulling the optical fluid upward with the flexible optical film 200.

[0111] In some embodiments, when the flexible optical film 200 is moved in the first direction, contaminants may accumulate at the wiper 220. In some embodiments, using the reset as described having regard to the flowchart 1400 shown in Figure 11 instead of cleaning by moving the flexible optical film 200 in the second direction generally as described having regard to the flowchart 1500 shown in Figure 12 may facilitate avoiding or reducing the accumulated contaminants at the wiper 220 being slowly pulled across the aperture 210 each cleaning cycle when cleaning by moving the flexible optical film 200 in the second direction.

[0112] In various embodiments, the second speed may be greater than the first speed. In some embodiments, the faster second speed may be used because the flexible optical film 200 may have already been cleaned during the cleaning cycles and the flexible optical film 200 may now merely need to be moved to a position wherein the sensor 112 can be used and further cleaning cycles can be performed. In some embodiments, the second speed may be more than 10 times the first speed. In various embodiments, this may facilitate quick resetting of the flexible optical film 200 position, which may be desirable to reduce interruption of use of the optical device 110. In various embodiments, block 1406 may direct the controller processor 1200 to reset the cleaning cycle counter stored in the location 1240 of the storage memory 1204 to zero and block 1406 may direct the controller processor 1200 to return to block 1402 for continued execution of the flowchart 1400.

[0113] In some embodiments, the wiper 220 may be a first wiper and the apparatus 120 may include a second wiper 1440 shown in Figure 3. In various embodiments, a portion of the seal 230 may act as the second wiper 1440. In some embodiments, the second wiper 1440 may be configured and act generally as described herein for the wiper 220 but for when the flexible optical film 200 is driven in the second direction opposite the arrow 222. In some embodiments, the controller 1002 shown in Figure 10 may be configured to, instead of causing a cleaning reset to be performed after the cleaning cycles are performed, cause second direction cleaning cycles to be performed by periodically causing the flexible optical film 200 to be moved in the second direction, generally similar to how the cleaning cycles are performed in the first direction.

[0114] Referring to Figure 12, a flowchart depicting blocks of code for directing the controller processor 1200 shown in Figure 10 to perform flexible optical film cleaning including cleaning in both the first and second directions, in accordance with various embodiments is shown generally at 1500. In various embodiments, the blocks of code included in the flowchart 1500 may be encoded in the block of codes 1290 of the program memory 1202 shown in Figure 10.

[0115] Referring to Figure 12, the flowchart 1500 begins with block 1502 which directs the controller processor 1200 to periodically cause a first direction cleaning cycle to be performed. In some embodiments, block 1502 may direct the controller processor 1200 to produce signals for causing at least one actuator to move the flexible optical film 200 in the first direction shown by the arrow 222 in Figure 3 relative to the first wiper 220 for a cleaning distance, the cleaning distance greater than a width of the portion of the aperture across which the flexible optical film 200 extends, such that the first direction cleaning cycle is performed a cleaning number of times. In various embodiments, block 1502 may include code generally similar to code included in block 1402 of the flowchart 1400 shown in Figure 11.

[0116] In various embodiments, after block 1502 has been executed or concurrent with a continuing execution of block 1502 wherein the controller processor 1200 periodically causes first direction cleaning cycles to be performed between waiting times and increments the cleaning cycle counter, block 1504 may be executed.

[0117] Block 1504 directs the controller processor 1200 to determine whether the cleaning number is greater than or equal to a cleaning number threshold, the cleaning number threshold being greater than 2. In various embodiments, the cleaning number threshold being greater than 2 may facilitate use of a longer flexible optical film and increase longevity of the flexible optical film. In various embodiments, block 1504 may include code generally similar to code included in the block 1404 of the flowchart 1400 shown in Figure 11.

[0118] If at block 1504, the controller processor 300 determines that the cleaning cycle counter is greater than or equal to the cleaning number threshold, then block 1504 may direct the controller processor 1200 to proceed to block 1506. If at block 1504, the controller processor 1200 determines that the cleaning cycle counter is less than the cleaning number threshold, then block 1504 may direct the controller processor 1200 to return to block 1502 for continued execution of block 1502.

[0119] Referring to Figure 12, block 1506 directs the controller processor 1200 to periodically cause a second direction cleaning cycle to be performed. In some embodiments, block 1506 may direct the controller processor 1200 to produce signals for causing the at least one actuator to move the flexible optical film 200 in the second direction relative to the second wiper for the cleaning distance. In some embodiments, block 1506 may include code generally similar to the code included in block 1502 but directing the controller processor 1200 to periodically produce signals for causing the second spool actuator 368 to drive the second spool 306 and cause the flexible optical film 200 to travel at in the second direction opposite to the direction shown by the arrow 222 in Figure 3 for the cleaning distance. In various embodiments, causing cleaning cycles to be performed in the second direction opposite to the first direction in this way may facilitate reducing or avoiding the time required to reset the film. In some embodiments, causing cleaning cycles to be performed in the second direction opposite to the first direction may reduce wasted energy on the reset, which may be particularly desirable in a battery powered system, for example.

[0120] In various embodiments, block 1506 may direct the controller processor 1200 to first reset the cleaning cycle counter stored in the location 1240 of the storage memory 1204 to zero and then to increment the cleaning cycle counter as described herein regarding block 1502 and 1402 with each performance of the second direction cleaning cycle. In some embodiments, block 1506 may include code generally similar to the code included in block 1504 such that once the cleaning cycle counter reaches the cleaning number threshold, block 1506 may direct the controller processor 1200 to return to block 1502 such that first direction cleaning cycles are performed again.

[0121] In various embodiments, execution of the flowchart 1500 shown in Figure 12 may facilitate cleaning cycles in both the first and second directions, which may facilitate efficient cleaning of the flexible optical film 200 and / or reduced wear of the flexible optical film 200.

[0122] Referring to Figure 13, there is shown a top view of part of the system 100 shown in Figures 1-3 with a portion of the housing 208 removed and the optical device 110 removed for illustration purposes, in accordance with various embodiments. In various embodiments, Figure 13 illustrates an example of a physical placement of the controller 1002 of the system 100. Referring to Figure 13, electrical wires or cables 1540 and 1542 may provide electrical communication between the controller 1002 and the first and second spool actuators (264 and 368 shown in Figure 3).

[0123] In various embodiments, a system generally similar to the system 100 shown in Figures 1 to 6 or an apparatus generally similar to the apparatus 500 shown in Figure 7 may include an aperture having a width and / or height chosen to suit an optical device included in the system.

[0124] In various embodiments, a system generally similar to the system 100 shown in Figures 1 to 6 or an apparatus generally similar to the apparatus 500 shown in Figure 7 may be configured such that the flexible optical film is moved “side-to- side” or “top-to-bottom” depending on application constraints.

[0125] In various embodiments, a system generally similar to the system 100 shown in Figures 1 to 6 or an apparatus generally similar to the apparatus 500 shown in Figure 7 may include a second spool that is undriven and the system or apparatus may be configured to drive the flexible optical film in only one direction.

[0126] While specific embodiments of the present disclosure have been described and illustrated, such embodiments should be considered illustrative of the present disclosure only and not as limiting the present disclosure as construed in accordance with the accompanying claims.

Claims

CLAIMS:

1. An apparatus for protecting an optical device during operation, the apparatus comprising: at least one flexible optical film having an outer optical surface and an inner optical surface configured to extend across at least a portion of an aperture configured to be used by the optical device; a wiper held in engagement with the outer optical surface of the at least one flexible optical film, the wiper configured to slide along the outer optical surface and dislodge contaminants from the outer optical surface when the outer optical surface is moved relative to the wiper; a base coupled to the wiper and engaging the inner optical surface of the at least one flexible optical film opposite the wiper, the base configured to hold the at least one flexible optical film between the base and the wiper while the outer optical surface is moved relative to the wiper wherein the base includes an optical portion in engagement with the inner optical surface of the at least one flexible optical film opposite the outer optical surface, the optical portion of the base extending across at least a portion of the aperture configured to be used by the optical device; and optical fluid including an intermediate optical fluid interposed between the optical portion of the base and the inner optical surface of the at least one flexible optical film.

2. The apparatus of claim 1 wherein the optical fluid includes a source optical fluid and the apparatus comprises:an optical fluid reservoir holding the source optical fluid, wherein the optical fluid reservoir encloses a source portion of the at least one flexible optical film, such that the source optical fluid is deposited on the inner optical surface of the at least one flexible optical film in the optical fluid reservoir.

3. The apparatus of claim 2 wherein a volume of the source optical fluid held in the optical fluid reservoir is more than 10 times a volume of the intermediate optical fluid interposed between the optical portion of the base and the inner optical surface of the at least one flexible optical film.

4. The apparatus of claim 2 or 3 comprising a filter configured to engage with the inner optical surface of the at least one flexible optical film adjacent to an exit of the optical fluid reservoir, the filter configured to capture particles from the source optical fluid as the at least one flexible optical film exits the optical fluid reservoir and is moved toward the optical portion of the base, wherein the filter is configured to allow a portion of the source optical fluid deposited on the inner optical surface to pass.

5. The apparatus of claim 4 wherein the filter is composed of a resiliently deformable porous fluid retaining material.

6. The apparatus of any one of claims 1 to 5 wherein the optical fluid has an index of refraction between about 1.45 and 1.80.

7. The apparatus of any one of claims 1 to 6 wherein the intermediate optical fluid fills a thickness of about 90 nm to 15 urn between the inner optical surface of the at least one flexible optical film and the optical portion of the base.

8. The apparatus of any one of claims 1 to 7 wherein the optical fluid has an index of refraction within 0.1 of an index of refraction of the at least one flexible optical film.

9. The apparatus of any one of claims 1 to 8 wherein the optical portion of the base has an index of refraction within 0.1 of an index of refraction of the at least one flexible optical film.

10. The apparatus of any one of claims 1 to 9 wherein the flexible optical film has a thickness between about 30 urn and 200 urn.

11. The apparatus of any one of claims 1 to 10 wherein the flexible optical film is configured to bend to a minimum bend radius of less than about 20 cm.

12. The apparatus of any one of claims 1 to 11 comprising a seal forming a continuous loop on the outer optical surface surrounding the aperture, the seal including the wiper.

13. The apparatus of any one of claims 1 to 12 comprising at least one actuator coupled between the at least one flexible optical film and the wiper, the at least one actuator configured to move the at least one flexible optical film relative to the wiper.

14. The apparatus of claim 13 wherein the at least one actuator is configured to selectively move the at least one flexible optical film relative to the wiper in a first direction and in a second direction opposite to the first direction.

15. The apparatus of claim 14 comprising at least one processor in communication with the at least one actuator, the at least one processor configured to: periodically cause a cleaning cycle to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film at a first speed in the first direction relative to the wiper for a cleaning distance, the cleaning distance greater than a width of the portion of the aperture across which the at least oneflexible optical film extends, such that the cleaning cycle is performed a cleaning number of times; determine that the cleaning number is greater than or equal to a cleaning number threshold, the cleaning number threshold being greater than 2; based on determining that the cleaning number is greater than or equal to the cleaning number threshold, cause a cleaning reset to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film at a second speed in the second direction for a reset distance greater than the cleaning distance.

16. The apparatus of claim 15 wherein the reset distance is about equal to the cleaning distance times the cleaning number.

17. The apparatus of claim 15 or 16 wherein the cleaning number threshold is greater than 10.

18. The apparatus of any one of claims 15 to 17 wherein the second speed is greater than the first speed.

19. The apparatus of claim 18 wherein the second speed is more than 10 times the first speed.

20. The apparatus of any one of claims 15 to 19 wherein the at least one processor is configured to wait for a waiting time between producing the signals for causing the at least one actuator to move the at least one flexible optical film in the first direction, the waiting time between about 1 minute and 8 hours.

21. The apparatus of claim 14 wherein the wiper is a first wiper, the apparatus comprising:a second wiper held in engagement with the outer optical surface of the at least one flexible optical film, the second wiper configured to slide along the outer optical surface and dislodge contaminants from the outer optical surface when the outer optical surface is moved in the second direction relative to the second wiper; the apparatus comprising at least one processor in communication with the at least one actuator, the at least one processor configured to: periodically cause a first direction cleaning cycle to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film in the first direction relative to the first wiper for a cleaning distance, the cleaning distance greater than a width of the portion of the aperture across which the at least one flexible optical film extends, such that the first direction cleaning cycle is performed a cleaning number of times; determine that the cleaning number is greater than or equal to a cleaning number threshold, the cleaning number threshold being greater than 2; based on determining that the cleaning number is greater than or equal to the cleaning number threshold, periodically cause a second direction cleaning cycle to be performed by producing signals for causing the at least one actuator to move the at least one flexible optical film in the second direction relative to the second wiper for the cleaning distance.

22. The apparatus of any one of claims 1 to 21 wherein the base is a rigid base.

23. The apparatus of any one of claims 1 to 22 wherein the base extends across the aperture.

24. The apparatus of any one of claims 1 to 23 wherein the at least one flexible optical film includes a continuous loop of flexible optical film having an environment facing portion including the outer and inner optical surfaces.

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