Configuring optical light path having beam overlap on image sensor

An accessory that is attachable to a device comprises an image sensor and a beam splitter having a first surface and a second surface. The beam splitter is configured to impinge light upon the first surface, and split the light impinging upon the first surface into at least a first beam, a second beam, and a third beam. The first beam travels from a first opening of the device to a second opening of the device along an optical path when the accessory is attached to the device, the second beam travels from the first surface to the image sensor, and the third beam travels from the second surface to the image sensor or a beam dump.

FIELD OF THE INVENTION

The present disclosure relates to systems and methods for configuring an optical light path and, in particular, to systems and methods for configuring components within a device to selectively direct light to an image sensor or other type of detector or sensor.

BACKGROUND OF THE INVENTION

Visual observation is a common technique for healthcare providers to determine a patient's health status. Many tools exist to assist healthcare providers with visual observations of patients. For example, an otoscope assists healthcare providers with viewing inside of a patient's ear, such as during regular health check-ups and/or to investigate ear symptoms. An ophthalmoscope assists healthcare providers with viewing inside of the fundus of a patient's eye, such as part of an eye exam and/or a routine physical exam. A dermatoscope assists healthcare providers with viewing skin lesions without the interference of skin surface reflections, which is useful in distinguishing between benign and malignant lesions on a patient's skin. These are but a few examples of tools that may assist a healthcare provider with visual observations of a patient.

Conventional tools that assist healthcare providers with visual observations, such as the ones described above, include a channel or opening that allows light to pass through the device, and may alter the light in some way (e.g., using lenses) based on the type of visual observation to be conducted using the device. In some cases, such tools may alternatively or additionally include a digital imaging component that allows the healthcare provider to capture images and/or video of an exam, which may be viewed in real time, and/or may be stored for review at a later time. However, tools that incorporate a digital imaging component block the opening that allows light to pass through the device during a traditional examination in order to capture light for the creation of digital images. Additionally, display devices that provide real time viewing (e.g., during a patient examination) using such tools are often disposed in a remote location from the device (e.g., on a computer monitor on a desk in the exam room), which causes a disruption in the workflow of the healthcare provider conducting the exam. For example, a healthcare provider may have to take their attention from the tool performing the visual observation to look at a monitor of the images being captured by the digital imaging component on a computer monitor, which may inhibit the healthcare provider's ability to make precise movements with the tool during the exam.

Examples of the present disclosure are directed toward overcoming the deficiencies described above.

SUMMARY

In an example of the present disclosure, a device comprises a housing defining an internal space that includes a first opening and a second opening. The device may also include an optics assembly disposed within the internal space, where the optics assembly is configured to receive light, via the first opening, from a source external to the housing, and direct the light to pass, through the housing, to the second opening along an optical path. The device may also include an accessory removably connectable to the housing. The accessory may comprise an image sensor and a beam splitter having a first surface and a second surface, such that when the accessory is removably connected to the housing, the light impinges upon the first surface. Additionally, when the accessory is removably connected to the housing, the beam splitter splits the light impinging upon the first surface into at least a first beam, a second beam, and a third beam. The first beam travels from the first opening to the second opening along the optical path, the second beam travels from the first surface to the image sensor, and the third beam travels from the second surface to the image sensor or a beam dump.

In another example of the present disclosure, an accessory attachable to a housing of a medical device comprises an image sensor and a beam splitter having a first surface and a second surface. When the accessory is attached to the housing of the medical device, the first surface of the beam splitter is configured to receive light via a first opening of the housing, and the beam splitter is configured to split the light into at least a first beam, a second beam, and a third beam. The first beam travels from the first surface to a second opening of the housing along a first optical path extending from the first surface to the second opening. The second beam travels from the first surface to the image sensor along a second optical path. The third beam travels from the first surface to the image sensor or a beam dump along a third optical path extending from the first surface to the image sensor or the beam dump via the second surface.

In a further example of the present disclosure, a method of manufacturing an accessory for a medical device includes providing a coupling mechanism for removably attaching the accessory to the medical device, providing an image sensor for converting light into an image or a video, and providing a beam splitter. When the accessory is attached to the housing of the medical device, the first surface of the beam splitter is configured to receive light via a first opening of the housing, and the beam splitter is configured to split the light into a first beam, a second beam, and a third beam. The first beam travels from the first surface to a second opening of the housing along a first optical path extending from the first surface to the second opening when the accessory is attached to the medical device via the coupling mechanism. The second beam travels from the first surface to the image sensor along a second optical path. The third beam travels from the first surface to the image sensor or a beam dump along a third optical path extending from the first surface to the image sensor or the beam dump via the second surface.

DETAILED DESCRIPTION

FIG.1illustrates a visual observation system100of the present disclosure including a device102configured to enable a healthcare provider104(or other user) to perform a visual observation of a patient106(or other user). In the illustrated example, the device102is an otoscope configured to assist the healthcare provider104with viewing inside of an ear of the patient106. It is understood that the depiction of the device102(e.g., an otoscope) is merely exemplary. In examples, the concepts described herein may be applicable to any other medical device that assists the healthcare provider104with visual observations of the patient106. Such devices may include, for example, probes, ophthalmoscopes, dermatoscopes, endoscopes, and the like. Additionally, while examples are generally described in relation to a handheld device, examples are considered in which the device102assists the healthcare provider104to perform visual observations of the patient106without being held by the healthcare provider104, such as worn on a head of the healthcare provider106(e.g., a binocular ophthalmoscope), mounted to and/or placed upon a surface, held and/or worn by the patient106, and so forth.

In examples, the device102includes a first end108and a second end110, which may be opposite one another on the device102. The first end108may be oriented towards (e.g., facing) the patient106and the second end110may be oriented towards (e.g., facing) the healthcare provider104during an examination of the patient106. In such an orientation, light112reflected by at least a portion of the patient106enters the first end108of the device102. The device102may include lenses, mirrors, beam splitters, or other light manipulating components tailored to assist the healthcare provider104with a particular type of visual observation of the patient106. As described herein, different types of devices may have different interior components to manipulate the light112based on a type of exam that the device102is intended to assist with. At least a portion of the light112passes through the device102, along with light manipulation components included in the device102, and out of the second end110of the device102to an eye of the healthcare provider104, enabling the healthcare provider104to make visual observations of the patient106. Although not explicitly pictured in the visual observation system100, the device102may be configured to have an accessory attached that captures a portion of the light112to generate images and/or video while the healthcare provider104performs the exam of the patient106, without impeding the healthcare provider104from viewing the portion of the patient in the manner described in relation toFIG.1.

FIG.2illustrates a cross-sectional view of a portion of an example visual observation tool200of the present disclosure. In this example, the visual observation tool200comprises an otoscope202, such as the otoscope described in relation toFIG.1. Additionally, the visual observation tool200comprises an accessory204that, in some examples, is removably connectable to a housing206of the otoscope202. For instance, the housing206may include an opening208that permits a portion of the accessory204to enter the housing206of the otoscope202. The housing206generally defines an internal space207which may contain an optics assembly210comprising components such as a light, optical fibers, lenses, mirrors, and the like. In such examples, at least a portion of the accessory204may be disposed within the internal space207when the accessory204is removably connected to the housing206.

In some examples, the optics assembly210receives light212via a first opening (e.g., the first end108ofFIG.1)214from a source external to the housing206. The optics assembly210directs the light212to pass through the housing206to a second opening216(e.g., the second end110ofFIG.1) along an optical path218. The optical path218permits the light212to pass from the first opening214of the otoscope202to the second opening216of the otoscope202, similar to the light112passing through the device102in relation toFIG.1. For instance, the light212may be reflected off of a portion of the patient106ofFIG.1during an exam by the healthcare provider104of the patient106. As the light212traverses the optical path218through the otoscope202, the healthcare provider104is able to view a portion of the patient106, such as an interior of an ear of the patient106, from the second opening216of the otoscope202.

As mentioned above, the visual observation tool200may also include an accessory204that is removably connected to the housing206. The accessory204may be connected to the housing206by a coupling mechanism such as a threaded fastener, a buckle, a clamp, a clasp, a hook and loop fastener, a latch, a pin, a snap fastener, or the like. When the accessory204is connected to the otoscope202, a portion220(indicated by patterned fill) of the accessory204that enters the otoscope202may intercept the optical path218. In examples, the accessory204includes a beam splitter222disposed in the portion220of the accessory204that intercepts the optical path218. The light212may impinge upon (e.g., strike the surface of) the beam splitter222as the light212travels along the optical path218. Based on a shape, configuration, surface treatment, and other factors discussed in more detail in relation toFIGS.4and5, the beam splitter222may direct portions of the light212to continue along the optical path218, be directed to an image sensor224included in the accessory204, and/or be directed to a beam dump (not shown). Although described in relation to an image sensor herein, other sensor types are also contemplated and may be used in place of or in addition to the image sensors described. For example, the visual observation tool200(and/or other devices described herein) may include a multispectral sensor that records signals, such as spectral information, that are used in assisting with a diagnosis of the patient106. The multispectral sensor may measure reflected energy within several specific sections, or bands, of the electromagnetic spectrum to generate a multispectral image. Other examples of sensor types are also considered.

For instance, the beam splitter222may split the light212such that a first beam226travels from the first opening214to the second opening216along the optical path218for manual viewing by the healthcare provider106. Additionally, in some cases, the beam splitter222may split the light212such that a second beam228travels from the beam splitter222to the image sensor224to form an image and/or a video in real time corresponding to what the healthcare provider106is manually viewing through the otoscope202. Further, in some examples, the beam splitter222may split the light212such that a third beam (not shown) also travels from the beam splitter222to the image sensor224to form an image and/or a video with the second beam228, where the third beam is used to eliminate visual effects such as ghosting and/or chromatic aberration in the image or video. In some cases, the beam splitter222may split the light212such that the third beam travels from the beam splitter222to a beam dump to reduce reflections and/or scattering of light in the internal space207. For instance, a beam dump is an optical element designed to absorb a beam of light. In examples, one or more lenses232may be disposed between the beam splitter222and the image sensor224to focus and/or divert the second beam228and/or the third beam as desired based on an application of the accessory204.

In some examples, the accessory204may include components such as a camera or other like imaging device configured to capture digital or other like images of the patient106adjacent the first opening214based on the second beam228and/or the third beam directed to the image sensor224. The accessory204may also include a controller234comprising an image processor configured to receive signals and/or other inputs from the image sensor224, and use the signals from the image sensor224to form a visual image or video of the patient106based on the signal. For example, the controller234may include a digital storage component, in communication with the image sensor224, that is configured to store an image or a video captured by the image sensor224. Such a visual image or video may be provided on a display236of the accessory204, and/or may be transmitted by the controller234to a remote display or storage for later viewing. For instance, the controller234may include a digital transfer component that is configured to transfer the image or the video from the digital storage component to a remote computing device wirelessly via BLUETOOTH®, WIFI®, or other like means. In some examples, the accessory204may include one or more ports, connectors, terminals, and/or other like connection devices configured to enable communication between the digital transfer component and one or more separate devices. In addition to the image processor, digital storage component, and digital transfer described above, the controller234may comprise memory, additional processors (e.g., a microprocessor or other components generally associated with or included in a computer, a tablet, a mobile phone, or other computing device), and/or other known controller components to facilitate the functionality described herein.

As described above, the accessory204may include a display236connected to the image processor of the controller234. The display236may comprise, for example, a liquid crystal display (LCD) screen, a light emitting diode (LED) display, a digital read-out, an interactive touch-screen, and/or any other like components configured to communicate information to the user. The display236may be configured to communicate such information, including images and/or video based on the second beam228and/or the third beam received by the image sensor224, substantially instantaneously and/or substantially continuously depending on the mode of operation of the accessory204.

FIG.3illustrates a cross-sectional view of a portion of another example visual observation tool300of the present disclosure. In this example, the visual observation tool300comprises an ophthalmoscope302, which the healthcare provider104may use to view inside of a fundus of an eye of the patient106, such as part of an eye exam and/or a routine physical exam. Additionally, the visual observation tool300comprises an accessory304that, in some examples, is removably connectable to a housing306of the ophthalmoscope302. For instance, the housing306may include an opening308that permits a portion of the accessory304to enter inside of the housing306of the ophthalmoscope302. The housing306generally defines an internal space310which may contain an optics assembly312comprising components such as a light, optical fibers, lenses, mirrors, and the like, similar to the optics assembly210described in relation toFIG.2.

Similar to the discussion above with regard toFIG.2, the optics assembly312receives light314via a first opening316(e.g., the first end108ofFIG.1) from a source external to the housing306. The optics assembly312directs the light314to pass through the housing306to a second opening318(e.g., the second end110ofFIG.1) along an optical path320. The optical path320permits the light314to pass from the first opening316of the ophthalmoscope302to the second opening318of the ophthalmoscope302, similar to the discussion of the light112passing through the device102in relation toFIG.1. For instance, the light314may be reflected off of a portion of the patient106ofFIG.1during an exam by the healthcare provider104of the patient106. As the light314traverses the optical path320through the ophthalmoscope302, the healthcare provider104is able to view a portion of the patient106, such as a fundus of an eye of the patient106, from the second opening318of the ophthalmoscope302.

As mentioned above, the visual observation tool300may also include an accessory304that is removably connected to the housing306. The accessory304may be connected to the housing306by a coupling mechanism as described above. When the accessory304is connected to the ophthalmoscope302, a portion322(indicated by patterned fill) of the accessory304that enters the ophthalmoscope302may intercept the optical path320. In examples, the accessory304includes a beam splitter324disposed in the portion322of the accessory304that intercepts the optical path320. The light314may impinge upon (e.g., strike the surface of) the beam splitter324as the light314travels along the optical path320. Based on a shape, configuration, surface treatment, and other factors discussed in more detail in relation toFIGS.4and5, the beam splitter324may direct portions of the light314to continue along the optical path320, be directed to an image sensor326included in the accessory304, and/or be directed to a beam dump.

For instance, the beam splitter324may split the light314such that a first beam328travels from the first opening316to the second opening318along the optical path320for manual viewing by the healthcare provider106. Additionally, in some cases, the beam splitter324may split the light314such that a second beam330travels from the beam splitter324to the image sensor326to form an image and/or a video in real time corresponding to what the healthcare provider106is manually viewing through the ophthalmoscope302. Further, in some examples, the beam splitter326may split the light314such that a third beam (not shown) also travels from the beam splitter324to the image sensor326to form an image and/or a video with the second beam330, where the third beam is used to eliminate visual effects such as ghosting and/or chromatic aberration in the image or video. In some cases, the beam splitter324may split the light314such that the third beam travels from the beam splitter324to a beam dump (not shown) to reduce reflections and/or scattering of light in the internal space310. In examples, one or more lenses334may be disposed between the beam splitter324and the image sensor326to focus and/or divert the second beam330and/or the third beam as desired based on an application of the accessory304.

In some examples, the accessory304may include components such as a camera or other like imaging device. The camera may be configured to capture digital or other like images of the patient106adjacent the first opening316based on the second beam330and/or the third beam directed to the image sensor326. The accessory304may also include a controller336comprising an image processor configured to receive signals and/or other inputs from the image sensor326, and use the signals from the image sensor326to form a visual image or video of the patient106based on the signal. For example, the controller336may include a digital storage component, in communication with the image sensor326, that is configured to store an image or a video captured by the image sensor326. Such a visual image or video may be provided on a display338of the accessory304, and/or may be transmitted by the controller336to a remote display or storage for later viewing. The display338may have similar functionalities and capabilities as the display236ofFIG.1. In examples, the controller336may include a digital transfer component that is configured to transfer the image or the video from the digital storage component to a remote computing device wirelessly via BLUETOOTH®, WIFI®, or other like means. In some examples, the accessory304may include one or more ports, connectors, terminals, and/or other like connection devices configured to enable communication between the digital transfer component and one or more separate devices. In addition to the image processor, digital storage component, and digital transfer described above, the controller336may comprise memory, additional processors (e.g., a microprocessor or other components generally associated with or included in a computer, a tablet, a mobile phone, or other computing device), and/or other known controller components to facilitate the functionality described herein.

FIG.4is a schematic illustration400of different beam splitter configurations that may be used in a visual observation tool in accordance with examples of the present disclosure. The schematic illustration400includes beam splitter configurations in which the beam splitter is a parallel plate having two surfaces that are substantially parallel to one another. The beam splitters in the schematic illustration400may be coated or uncoated on either of the substantially parallel surfaces. The thickness of the beam splitters in the schematic illustration400may range from approximately 1 micron to approximately 50 millimeters. In further examples, the thickness of the beam splitter may be greater than or less than those noted above. Any of the beam splitter configurations described in relation toFIG.4andFIG.5may be polarized or unpolarized. In the examples illustrated inFIG.4andFIG.5, beams of light (e.g., the first beam226and the first beam328) that traverse an optical path (e.g., the optical path218and the optical path320) are not illustrated for clarity.

A configuration402illustrates a beam splitter404that is a relatively thin (e.g., 0.1 micron to 10 millimeters) parallel plate, which is configured for a finite conjugate application. A finite conjugate application is a configuration in which an object (e.g., a portion of the patient106being viewed by the healthcare provider104using the device102) or intermediate image plane is located at a finite distance from the beam splitter404. In a finite conjugate application, light is reflected from both the front and rear surface onto an image sensor406. For example, light408impinging upon the beam splitter404is split into a first beam410and a second beam412. The first beam410is reflected from a first surface414of the beam splitter404to the image sensor406, and the second beam412is reflected from the first surface414of the beam splitter, to a second surface416of the beam splitter, and then to the image sensor406. A lens418may be configured between the beam splitter414and the image sensor406to focus the first beam410and the second beam412on the image sensor406.

In some cases, the beam splitter404causes chromatic aberration and/or ghost images on the image sensor406due to image shift between light reflected from both surfaces of the beam splitter404. Depending on a thickness of the beam splitter404and image shift relative to the image sensor406, image resolution may be compromised in such scenarios. However, ghosting and chromatic aberration may be resolved by utilizing a relatively thin (e.g., 0.1 micron to 1 millimeter) beam splitter, such as a pellicle beam splitter.

A configuration420illustrates a beam splitter422that is a relatively thick (e.g., 5 millimeters to 50 millimeters) parallel plate, which is also configured for a finite conjugate application. Similar to the discussion above, light424impinging upon the beam splitter422is split into a first beam426and a second beam428. The first beam426is reflected from a first surface430of the beam splitter422to an image sensor432. However, the second beam428is reflected from the first surface430of the beam splitter, to a second surface434of the beam splitter, and then away from a lens436and the image sensor432, such as to a beam dump437. Directing the second beam428away from the lens436and the image sensor432may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter422and the image sensor432are housed.

A configuration438illustrates a beam splitter440that is a relatively thick (e.g., 5 millimeters to 50 millimeters) parallel plate, which is also configured for a finite conjugate application. Similar to the discussion above, light442impinging upon the beam splitter440is split into a first beam444and a second beam446. The first beam444in this example is reflected from a first surface448of the beam splitter440to a beam dump449. Additionally, the second beam446is reflected from the first surface448of the beam splitter440, to a second surface450of the beam splitter, and then towards an image sensor452by way of a lens454. Directing the first beam444away from the lens454and the image sensor452may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter440and the image sensor452are housed.

A configuration456illustrates a beam splitter458that is a parallel plate configured for an infinite conjugate application. An infinite conjugate application is a configuration in which an object (e.g., a portion of the patient106being viewed by the healthcare provider104using the device102) is located at an infinite distance from the beam splitter458. If an intermediate image plane is present in the infinite conjugate application, a collimating lens460is configured to move a virtual image of the object to infinity. In an infinite conjugate application, light is reflected from both the front and rear surface of the beam splitter458onto an image sensor462. For example, light464impinging upon the beam splitter458is split into a first beam466and a second beam468. The first beam466is reflected from a first surface470of the beam splitter458to the image sensor462, and the second beam468is reflected from the first surface470of the beam splitter, to a second surface472of the beam splitter, and then to the image sensor462. A lens474may be configured between the beam splitter458and the image sensor462to focus the first beam466and the second beam468on the image sensor462.

Unlike the configuration402that included a finite conjugate application, the configuration456the first beam466and the second beam468converge and overlap on the image sensor462. Consequently, there is no image shift between the first beam466and the second beam468, and the thickness of the beam splitter458does not affect the image quality of the image created by the image sensor462. Thus, effects such as chromatic aberration and/or ghost images may be avoided in the configuration456.

FIG.5is a schematic illustration500of additional beam splitter configurations that may be used in a visual observation tool in accordance with examples of the present disclosure. The schematic illustration500includes beam splitter configurations in which the beam splitter is a wedge plate having two surfaces that are at an angle greater than 0 degrees and less than 180 degrees relative to one another (e.g., not parallel to one another). The beam splitters in the schematic illustration500may be coated or uncoated on either of the angled surfaces. Generally, a wedged plate is used to reflect light from either a front surface or a rear surface onto an image sensor. The light from the other surface (e.g., the surface that does not reflect light to the image sensor) will miss a lens between the beam splitter and the image sensor, and will be terminated by a beam dump. Using a wedge plate as a beam splitter may change the boresight of the healthcare provider104when performing manual viewing using the device102. However, the boresight alterations may be corrected with additional optical components (such as a wedge substrate) after the beam passes the beam splitter and before the beam leaves the device102to be viewed by the healthcare provider104.

For example, a configuration502illustrates a beam splitter504that is configured as a wedge plate. Light506impinging upon the beam splitter504is split into a first beam508and a second beam510. The first beam508in this example is reflected from a first surface512of the beam splitter504to an image sensor514via a lens516. The second beam510is reflected from the first surface512of the beam splitter504, to a second surface518of the beam splitter, to a reverse side517of the first surface518of the beam splitter. The reverse side517of the first surface518of the beam splitter504directs the second beam510to a beam dump519. The beam dump519in the configuration502may be on a different side of the beam splitter504from which the light506originated. Directing the second beam510away from the lens516and the image sensor514may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter504and the image sensor514are housed.

A configuration520illustrates a beam splitter522that is also configured as a wedge plate. Light524impinging upon the beam splitter522is split into a first beam526and a second beam528. The first beam526in this example is reflected from a first surface530of the beam splitter522to an image sensor532via a lens534. The second beam528is reflected from the first surface530of the beam splitter522, to a second surface536of the beam splitter, and then to a beam dump537. The beam dump in the configuration520may be on a same side of the beam splitter522from which the light534originated. Similar to the discussion above, directing the second beam528away from the lens534and the image sensor532may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter522and the image sensor532are housed.

Additionally, a configuration538illustrates a beam splitter540that is configured as a wedge plate. Light542impinging upon the beam splitter540is split into a first beam544and a second beam546. The first beam544in this example is reflected from a first surface548of the beam splitter540to a beam dump549on a same side of the beam splitter540from which the light542originated. The second beam546is reflected from the first surface548of the beam splitter540, to a second surface550of the beam splitter, to a reverse side551of the first surface548of the beam splitter. The reverse side551of the first surface548of the beam splitter540directs the second beam546to an image sensor552via a lens554. Similar to the discussion above, directing the first beam544away from the lens554and the image sensor552may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter540and the image sensor552are housed.

A configuration556illustrates a beam splitter558that is also configured as a wedge plate. Light560impinging upon the beam splitter558is split into a first beam562and a second beam564. The first beam562in this example is reflected from a first surface566of the beam splitter558to a beam dump567on a different side of the beam splitter558from which the light560originated. The second beam562is reflected from the first surface566of the beam splitter558, to a second surface568of the beam splitter, to a reverse side569of the first surface566of the beam splitter. The reverse side569of the first surface566of the beam splitter558directs the second beam562to an image sensor570via a lens572. Similar to the discussion above, directing the first beam562away from the lens572and the image sensor570may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter558and the image sensor570are housed.

Although not explicitly pictured, other beam splitter configurations may be used in any of the described devices as well. For instance, a device may include a cube beam splitter comprised of prisms with a resin or cement layer in the interface(s) between the prisms. The resin or cement layer may be thin (e.g., 0.1 micron to 1 millimeter), which may minimize boresight offset of the cube beam splitter. A cube beam splitter may be employed in finite and/or infinite conjugate applications.

Additionally or alternatively, a beam splitter with a geometrically-patterned coating may be used in any of the described devices. The geometrically-patterned coating may reflect light in the coated area of the beam splitter, and allow light to transmit through the uncoated area of the beam splitter. An example of a beam splitter with a geometrically-patterned coating is a polka-dot beam splitter.

In some examples, a prism may be used as a beam splitter in any of the described devices. One such example is a Wollaston prism, which consists of two orthogonal prisms made of birefringent material. A Wollaston prism splits indecent light into two (or more) beams with orthogonal polarizations. One of the beams from the Wollaston prism is directed to an image sensor, and another of the beams may be directed to a healthcare provider for direct viewing.

FIG.6illustrates configurations600for a polarizer to be removed from a polarized sheet that may be incorporated into a visual observation tool in accordance with examples of the present disclosure. In some examples, one or more polarizers may be used to reduce reflection and glare in imaging applications such as medical devices as described herein, but also in applications such as photography, machine vision, microscopy, and the like. In applications that utilize active illumination, in which lighting whose direction, intensity and pattern are controlled by commands or signals, two (or more) crossed polarizers may be used to reduce reflection and glare. The two or more crossed polarizers may be manufactured using a die cutting process, in which a machine cuts shapes out of a material (plastic, rubber, chipboard, cloth, paper, foam, sheet metal, etc.) using a specialized tool (a die) to cut the material using a press.

Polarizers maximize glare and reflection reduction when a viewing polarizer is oriented perpendicularly to the polarizing direction of the reflected light. The reflected light, in some examples, is controlled by an illumination polarizer. In some devices, the viewing polarizer and/or the illumination polarizer may be rotated to achieve the desired orientation between the two polarizers. However, many devices include built-in polarizers at fixed orientations, so performance of the polarizers is determined by the angle of tolerance in manufacturing and assembling the device that includes the polarizers. Oftentimes, manufacturing processes tolerate several degrees of deviation from a polarization axis of the polarizers to the die cutter, especially when there is no active measurement during the manufacturing process. When a device is assembled, additional deviation of the desired angle between the polarizers may be introduced by mechanical tolerance between mated parts of the device. The compounded effect of such tolerances results in glare and/or reflection in images generated by the device, and/or in direct viewing through a device. Consequently, image contrast and quality are sacrificed.

The described techniques remedy the deficiencies of conventional polarizer manufacturing processes by cutting a viewing polarizer and an illumination polarizer from a same sheet using a die cutter. In some examples, a viewing polarizer and/or accompanying illumination polarizer are cut to have a unique shape and/or tab to fit into mating features of a mechanical holder of a device, such that the polarizers fit in a desired orientation but do not fit into the device in other orientations. Orienting the viewing polarizer and the illumination polarizer inside of the device based on the mating features ensures that the light is polarized by the polarizers correctly to minimize or eliminate glare and reflections, even if there is misalignment between the polarizer sheet and the die cutter. For instance, if the polarizer sheet is misaligned from the die cutter, both the viewing polarizer and the illumination polarizer will be misaligned by the same amount, and the misalignment of both will be canceled out when inserted into the device.

To illustrate, a polarizer sheet602includes an illumination polarizer604and a viewing polarizer606which are to be cut from the polarizer sheet602by a die cutter. The illumination polarizer604includes lines608(a) corresponding to a polarization direction of the polarizer sheet602. Additionally, the viewing polarizer606includes lines608(b) corresponding to the polarization direction of the polarizer sheet602. The lines608(a) and the lines608(b) (collectively, lines608) are in a same direction for both the illumination polarizer604and the viewing polarizer606. The lines608are also substantially parallel or perpendicular to lines610, which correspond to an orientation of the die cutter.

The illumination polarizer604also includes at least a tab612and a notch614that are used to orient the illumination polarizer604inside of a device in a desired orientation, and prevent the illumination polarizer604from being installed in the device in another orientation than the desired orientation. Similarly, the viewing polarizer606includes a tab616which may be used to orient the viewing polarizer606inside of the device in a desired orientation as well. When the illumination polarizer604and the viewing polarizer606are oriented in the device in the desired orientations using the tabs612and616and the notch614, the lines608(a) are perpendicular to the lines608(b), thus polarizing light entering the device.

A polarizer sheet618also includes an illumination polarizer620and a viewing polarizer622which are to be cut from the polarizer sheet618by a die cutter. The illumination polarizer620includes lines624(a) corresponding to a polarization direction of the polarizer sheet618. Additionally, the viewing polarizer622includes lines624(b) corresponding to the polarization direction of the polarizer sheet618. The lines624(a) and the lines624(b) (collectively, lines624) are in a same direction for both the illumination polarizer620and the viewing polarizer622. However, the lines624are not, in this case, substantially parallel or perpendicular to lines626, which correspond to an orientation of the die cutter. As noted above, the polarizer sheet618may be misaligned from the die cutter during manufacture of the illumination polarizer620and the viewing polarizer622.

However, the misalignment may be resolved by cutting the illumination polarizer620and the viewing polarizer622from the same polarizer sheet618, and using shapes of the illumination polarizer620and the viewing polarizer622to correctly orient these polarizers inside of a device. For instance, the illumination polarizer620includes at least a tab628and a notch630that are used to orient the illumination polarizer620inside of a device in a desired orientation, and prevent the illumination polarizer620from being installed in the device in another orientation than the desired orientation. Similarly, the viewing polarizer622includes a tab632which may be used to orient the viewing polarizer622inside of the device in a desired orientation as well. When the illumination polarizer620and the viewing polarizer622are oriented in the device in the desired orientations using the tabs628and632and the notch630, the lines624(a) are still perpendicular to the lines624(b), regardless of the misalignment of the die cutter relative to the polarizer sheet618. Accordingly, light entering the device is still polarized to correct glare and reflections, despite such misalignment.

FIG.7illustrates a cross-sectional view700of a portion of an example visual observation tool incorporating polarizers according to the present disclosure. The cross-sectional view700illustrates an ophthalmoscope702that has incorporated polarizers, but any medical device, microscope, camera, machine vision tool, or other device may incorporate the described techniques without departing from the scope of the disclosure. The ophthalmoscope702includes an illumination polarizer704and a viewing polarizer706, similar to the discussion above in relation toFIG.6.

A pop-out view708illustrates an orientation of the illumination polarizer704inside of the ophthalmoscope702. The illumination polarizer704includes a tab710which may correspond to the tab612and/or the tab618ofFIG.6. The illumination polarizer704also includes and a notch712, which may correspond to the notch614and/or the notch630ofFIG.6. The tab710and the notch712provide a shape for the illumination polarizer704that ensures that the illumination polarizer704is oriented correctly inside an opening714of the ophthalmoscope702, and is prevented from being installed in another orientation other than the correct orientation.

Additionally, a pop-out view716illustrates an orientation of the viewing polarizer706inside of the ophthalmoscope702. The viewing polarizer706includes a tab718which may correspond to the tab616and/or the tab632ofFIG.6. The tab718provides a shape for the viewing polarizer706that ensures that the viewing polarizer706is oriented correctly inside an opening720of the ophthalmoscope702, and is prevented from being installed in another orientation other than the correct orientation. Further, the orientations of the illumination polarizer704and the viewing polarizer706based on the shapes of the polarizers, in combination with being cut from a same polarizer sheet as described in relation toFIG.6, ensures that light722entering the ophthalmoscope702is polarized to reduce or eliminate reflections and glare.

FIG.8illustrates a flowchart outlining an example method800of manufacturing an accessory for a visual observation tool in accordance with the present disclosure. In some examples, the method800may be performed by one or more computing devices configured to manufacture visual observation tools. Reference will be made throughout the discussion of the method800toFIGS.2,3,4, and5, which show schematic illustrations of visual observation tools and/or beam splitters.

At operation802, the method of manufacture includes providing a coupling mechanism for removably attaching an accessory204and/or an accessory304to a device, such as an otoscope202, and ophthalmoscope302, a dermatoscope, or other type of device. For example, the coupling mechanism may be a threaded fastener, a buckle, a clamp, a clasp, a hook and loop fastener, a latch, a pin, a snap fastener, or the like.

At operation804, the method of manufacture includes providing an image sensor, such as the image sensor224and/or the image sensor326, for converting variable attenuation of light waves into signals as the light waves pass through and/or reflect off of objects. The image sensor generates an image or a video from the signals converted from the light waves. For instance, the image sensor224is included in the accessory204. The image sensor224may be in communication with the controller234comprising an image processor configured to receive signals and/or other inputs from the image sensor224, and use the signals from the image sensor224to form a visual image or video of the patient106based on the signal.

At operation806, the method of manufacture includes providing a beam splitter, such as the beam splitter222and/or the beam splitter324, where the beam splitter has a first surface and a second surface. The beam splitter222and/or the beam splitter324may take any one of a variety of configurations, such as the parallel plate configurations402,420,438, and/or456described in relation toFIG.4, the wedge plate configurations502,520,538, and/or556described in relation toFIG.5, a cube beam splitter, a beam splitter having a geometric coating, a prism, or the like.

At operation808, the method of manufacture includes configuring the beam splitter222in the accessory204such that light impinging upon the first surface is split into a first beam226, a second beam228, and a third beam (e.g., seeFIGS.4and5). At operation810, the method of manufacture includes configuring the beam splitter222in the accessory204such that the first beam226travels from a first opening214of the device to a second opening216of the device along an optical path218when the accessory204is attached to the device via the coupling mechanism. Configuring the beam splitter222in this way enables the healthcare provider104to perform a manual examination of the patient by viewing through the device.

At operation812, the method of manufacture includes configuring the beam splitter222in the accessory204such that the second beam228travels from the first surface of the beam splitter222to the image sensor224. Additionally, at operation814, the method of manufacture includes configuring the beam splitter222in the accessory204such that the third beam travels from the second surface of the beam splitter222to the image sensor224or a beam dump. For instance, the beam splitter222may be configured to direct the third beam to the image sensor224to reduce or eliminate visual effects in digital images or video such as ghosting or chromatic aberration. Alternatively or additionally, the beam splitter222may be configured to direct the third beam to a beam dump (e.g., seeFIGS.4and5) to reduce reflections and/or scattering of light in the internal space207.

The described optical configurations enable a healthcare provider to utilize an accessory with a medical device to capture images and/or video of an exam of a patient while performing the exam using manual techniques that the healthcare provider is accustomed to. In this way, the healthcare provider can make precise measurements and/or movements with the medical device during exams of a patient's eyes, ears, and other body parts using the medical device, and capture images and/or video during the exam for later reference or real time viewing by others (e.g., a nurse or medical student).