Patent Description:
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.

<CIT> describes an endoscope having an endoscope objective mounted on its distal end. The image produced by the objective is directed by an image-conductor unit to the proximal end, at which it can be observed by means of an ocular. An illuminating device comprises a fiber optic, which conducts the light from a light source to the distal end and which surrounds, at least partly, the image-conductor unit. A deflection element can be placed in the path of the observation beam in front of the ocular, so that the observation beam is directed, at least partially, onto the pickup element of a video camera.

<CIT> describes a compact wavefront sensor module to be attached to or integrated with an ophthalmic instrument for eye examination and/or vision correction procedures. A compensating lens is positioned so that the compensating lens, a dichroic or short pass beam splitter and a first lens are aligned to form a first optical path between them. A folded optical path extends from a pair of stereoscopic viewing ports, which are located at a position behind the compensating lens, to a pair of stereoscopic eyepieces. The dichroic or short pass beam splitter reflects a wavefront beam to detector along a second optical path.

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

In a further example of the present disclosure, not falling within the scope of the claimed invention, 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.

<FIG> illustrates a visual observation system <NUM> of the present disclosure including a device <NUM> configured to enable a healthcare provider <NUM> (or other user) to perform a visual observation of a patient <NUM> (or other user). In the illustrated example, the device <NUM> is an otoscope configured to assist the healthcare provider <NUM> with viewing inside of an ear of the patient <NUM>. It is understood that the depiction of the device <NUM> (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 provider <NUM> with visual observations of the patient <NUM>. 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 device <NUM> assists the healthcare provider <NUM> to perform visual observations of the patient <NUM> without being held by the healthcare provider <NUM>, such as worn on a head of the healthcare provider <NUM> (e.g., a binocular ophthalmoscope), mounted to and/or placed upon a surface, held and/or worn by the patient <NUM>, and so forth.

In examples, the device <NUM> includes a first end <NUM> and a second end <NUM>, which may be opposite one another on the device <NUM>. The first end <NUM> may be oriented towards (e.g., facing) the patient <NUM> and the second end <NUM> may be oriented towards (e.g., facing) the healthcare provider <NUM> during an examination of the patient <NUM>. In such an orientation, light <NUM> reflected by at least a portion of the patient <NUM> enters the first end <NUM> of the device <NUM>. The device <NUM> may include lenses, mirrors, beam splitters, or other light manipulating components tailored to assist the healthcare provider <NUM> with a particular type of visual observation of the patient <NUM>. As described herein, different types of devices may have different interior components to manipulate the light <NUM> based on a type of exam that the device <NUM> is intended to assist with. At least a portion of the light <NUM> passes through the device <NUM>, along with light manipulation components included in the device <NUM>, and out of the second end <NUM> of the device <NUM> to an eye of the healthcare provider <NUM>, enabling the healthcare provider <NUM> to make visual observations of the patient <NUM>. Although not explicitly pictured in the visual observation system <NUM>, the device <NUM> may be configured to have an accessory attached that captures a portion of the light <NUM> to generate images and/or video while the healthcare provider <NUM> performs the exam of the patient <NUM>, without impeding the healthcare provider <NUM> from viewing the portion of the patient in the manner described in relation to <FIG>.

<FIG> illustrates a cross-sectional view of a portion of an example visual observation tool <NUM> of the present disclosure. In this example, the visual observation tool <NUM> comprises an otoscope <NUM>, such as the otoscope described in relation to <FIG>. Additionally, the visual observation tool <NUM> comprises an accessory <NUM> that, in some examples, is removably connectable to a housing <NUM> of the otoscope <NUM>. For instance, the housing <NUM> may include an opening <NUM> that permits a portion of the accessory <NUM> to enter the housing <NUM> of the otoscope <NUM>. The housing <NUM> generally defines an internal space <NUM> which may contain an optics assembly <NUM> comprising components such as a light, optical fibers, lenses, mirrors, and the like. In such examples, at least a portion of the accessory <NUM> may be disposed within the internal space <NUM> when the accessory <NUM> is removably connected to the housing <NUM>.

In some examples, the optics assembly <NUM> receives light <NUM> via a first opening (e.g., the first end <NUM> of <FIG>) <NUM> from a source external to the housing <NUM>. The optics assembly <NUM> directs the light <NUM> to pass through the housing <NUM> to a second opening <NUM> (e.g., the second end <NUM> of <FIG>) along an optical path <NUM>. The optical path <NUM> permits the light <NUM> to pass from the first opening <NUM> of the otoscope <NUM> to the second opening <NUM> of the otoscope <NUM>, similar to the light <NUM> passing through the device <NUM> in relation to <FIG>. For instance, the light <NUM> may be reflected off of a portion of the patient <NUM> of <FIG> during an exam by the healthcare provider <NUM> of the patient <NUM>. As the light <NUM> traverses the optical path <NUM> through the otoscope <NUM>, the healthcare provider <NUM> is able to view a portion of the patient <NUM>, such as an interior of an ear of the patient <NUM>, from the second opening <NUM> of the otoscope <NUM>.

As mentioned above, the visual observation tool <NUM> may also include an accessory <NUM> that is removably connected to the housing <NUM>. The accessory <NUM> may be connected to the housing <NUM> by 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 accessory <NUM> is connected to the otoscope <NUM>, a portion <NUM> (indicated by patterned fill) of the accessory <NUM> that enters the otoscope <NUM> may intercept the optical path <NUM>. In examples, the accessory <NUM> includes a beam splitter <NUM> disposed in the portion <NUM> of the accessory <NUM> that intercepts the optical path <NUM>. The light <NUM> may impinge upon (e.g., strike the surface of) the beam splitter <NUM> as the light <NUM> travels along the optical path <NUM>. Based on a shape, configuration, surface treatment, and other factors discussed in more detail in relation to <FIG> and <FIG>, the beam splitter <NUM> may direct portions of the light <NUM> to continue along the optical path <NUM>, be directed to an image sensor <NUM> included in the accessory <NUM>, 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 tool <NUM> (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 patient <NUM>. 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.

According to the invention as defined in independent claim <NUM>, which relates to an accessory attachable to a housing of a medical device, the beam splitter <NUM> splits the light <NUM> such that a first beam <NUM> travels from the first opening <NUM> to the second opening <NUM> along the optical path <NUM> for manual viewing by the healthcare provider <NUM>. Additionally, the beam splitter <NUM> splits the light <NUM> such that a second beam <NUM> travels from the beam splitter <NUM> to the image sensor <NUM> to form an image and/or a video in real time corresponding to what the healthcare provider <NUM> is manually viewing through the otoscope <NUM>. Further, according to one alternative of the invention as defined in independent claim <NUM>, the beam splitter <NUM> Z splits the light <NUM> such that a third beam (not shown) also travels from the beam splitter <NUM> to the image sensor <NUM> to form an image and/or a video with the second beam <NUM>, where the third beam is used to eliminate visual effects such as ghosting and/or chromatic aberration in the image or video. According to the other alternative defined in independent claim <NUM>, the beam splitter <NUM> splits the light <NUM> such that the third beam travels from the beam splitter <NUM> to a beam dump to reduce reflections and/or scattering of light in the internal space <NUM>. For instance, a beam dump is an optical element designed to absorb a beam of light. In examples, one or more lenses <NUM> may be disposed between the beam splitter <NUM> and the image sensor <NUM> to focus and/or divert the second beam <NUM> and/or the third beam as desired based on an application of the accessory <NUM>.

In some examples, the accessory <NUM> may include components such as a camera or other like imaging device configured to capture digital or other like images of the patient <NUM> adjacent the first opening <NUM> based on the second beam <NUM> and/or the third beam directed to the image sensor <NUM>. The accessory <NUM> may also include a controller <NUM> comprising an image processor configured to receive signals and/or other inputs from the image sensor <NUM>, and use the signals from the image sensor <NUM> to form a visual image or video of the patient <NUM> based on the signal. For example, the controller <NUM> may include a digital storage component, in communication with the image sensor <NUM>, that is configured to store an image or a video captured by the image sensor <NUM>. Such a visual image or video may be provided on a display <NUM> of the accessory <NUM>, and/or may be transmitted by the controller <NUM> to a remote display or storage for later viewing. For instance, the controller <NUM> may 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 accessory <NUM> may 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 controller <NUM> may 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 accessory <NUM> may include a display <NUM> connected to the image processor of the controller <NUM>. The display <NUM> may 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 display <NUM> may be configured to communicate such information, including images and/or video based on the second beam <NUM> and/or the third beam received by the image sensor <NUM>, substantially instantaneously and/or substantially continuously depending on the mode of operation of the accessory <NUM>.

<FIG> illustrates a cross-sectional view of a portion of another example visual observation tool <NUM> of the present disclosure. In this example, the visual observation tool <NUM> comprises an ophthalmoscope <NUM>, which the healthcare provider <NUM> may use to view inside of a fundus of an eye of the patient <NUM>, such as part of an eye exam and/or a routine physical exam. Additionally, the visual observation tool <NUM> comprises an accessory <NUM> that, in some examples, is removably connectable to a housing <NUM> of the ophthalmoscope <NUM>. For instance, the housing <NUM> may include an opening <NUM> that permits a portion of the accessory <NUM> to enter inside of the housing <NUM> of the ophthalmoscope <NUM>. The housing <NUM> generally defines an internal space <NUM> which may contain an optics assembly <NUM> comprising components such as a light, optical fibers, lenses, mirrors, and the like, similar to the optics assembly <NUM> described in relation to <FIG>.

Similar to the discussion above with regard to <FIG>, the optics assembly <NUM> receives light <NUM> via a first opening <NUM> (e.g., the first end <NUM> of <FIG>) from a source external to the housing <NUM>. The optics assembly <NUM> directs the light <NUM> to pass through the housing <NUM> to a second opening <NUM> (e.g., the second end <NUM> of <FIG>) along an optical path <NUM>. The optical path <NUM> permits the light <NUM> to pass from the first opening <NUM> of the ophthalmoscope <NUM> to the second opening <NUM> of the ophthalmoscope <NUM>, similar to the discussion of the light <NUM> passing through the device <NUM> in relation to <FIG>. For instance, the light <NUM> may be reflected off of a portion of the patient <NUM> of <FIG> during an exam by the healthcare provider <NUM> of the patient <NUM>. As the light <NUM> traverses the optical path <NUM> through the ophthalmoscope <NUM>, the healthcare provider <NUM> is able to view a portion of the patient <NUM>, such as a fundus of an eye of the patient <NUM>, from the second opening <NUM> of the ophthalmoscope <NUM>.

As mentioned above, the visual observation tool <NUM> may also include an accessory <NUM> that is removably connected to the housing <NUM>. The accessory <NUM> may be connected to the housing <NUM> by a coupling mechanism as described above. When the accessory <NUM> is connected to the ophthalmoscope <NUM>, a portion <NUM> (indicated by patterned fill) of the accessory <NUM> that enters the ophthalmoscope <NUM> may intercept the optical path <NUM>. In examples, the accessory <NUM> includes a beam splitter <NUM> disposed in the portion <NUM> of the accessory <NUM> that intercepts the optical path <NUM>. The light <NUM> may impinge upon (e.g., strike the surface of) the beam splitter <NUM> as the light <NUM> travels along the optical path <NUM>. Based on a shape, configuration, surface treatment, and other factors discussed in more detail in relation to <FIG> and <FIG>, the beam splitter <NUM> may direct portions of the light <NUM> to continue along the optical path <NUM>, be directed to an image sensor <NUM> included in the accessory <NUM>, and/or be directed to a beam dump.

According to the invention as defined in independent claim <NUM>, which relates to an accessory attachable to a housing of a medical device, the beam splitter <NUM> splits the light <NUM> such that a first beam <NUM> travels from the first opening <NUM> to the second opening <NUM> along the optical path <NUM> for manual viewing by the healthcare provider <NUM>. Additionally, the beam splitter <NUM> splits the light <NUM> such that a second beam <NUM> travels from the beam splitter <NUM> to the image sensor <NUM> to form an image and/or a video in real time corresponding to what the healthcare provider <NUM> is manually viewing through the ophthalmoscope <NUM>. Further, according to one alternative of the invention as defined in independent claim <NUM>, the beam splitter <NUM> splits the light <NUM> such that a third beam (not shown) also travels from the beam splitter <NUM> to the image sensor <NUM> to form an image and/or a video with the second beam <NUM>, where the third beam is used to eliminate visual effects such as ghosting and/or chromatic aberration in the image or video. According to the other alternative defined in independent claim <NUM>, the beam splitter <NUM> splits the light <NUM> such that the third beam travels from the beam splitter <NUM> to a beam dump (not shown) to reduce reflections and/or scattering of light in the internal space <NUM>. In examples, one or more lenses <NUM> may be disposed between the beam splitter <NUM> and the image sensor <NUM> to focus and/or divert the second beam <NUM> and/or the third beam as desired based on an application of the accessory <NUM>.

In some examples, the accessory <NUM> may 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 patient <NUM> adjacent the first opening <NUM> based on the second beam <NUM> and/or the third beam directed to the image sensor <NUM>. The accessory <NUM> may also include a controller <NUM> comprising an image processor configured to receive signals and/or other inputs from the image sensor <NUM>, and use the signals from the image sensor <NUM> to form a visual image or video of the patient <NUM> based on the signal. For example, the controller <NUM> may include a digital storage component, in communication with the image sensor <NUM>, that is configured to store an image or a video captured by the image sensor <NUM>. Such a visual image or video may be provided on a display <NUM> of the accessory <NUM>, and/or may be transmitted by the controller <NUM> to a remote display or storage for later viewing. The display <NUM> may have similar functionalities and capabilities as the display <NUM> of <FIG>. In examples, the controller <NUM> may 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 accessory <NUM> may 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 controller <NUM> may 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> is a schematic illustration <NUM> of different beam splitter configurations that may be used in a visual observation tool in accordance with examples of the present disclosure. The schematic illustration <NUM> includes 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 illustration <NUM> may be coated or uncoated on either of the substantially parallel surfaces. The thickness of the beam splitters in the schematic illustration <NUM> may range from approximately <NUM> micron to approximately <NUM> 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 to <FIG> and <FIG> may be polarized or unpolarized. In the examples illustrated in <FIG> and <FIG>, beams of light (e.g., the first beam <NUM> and the first beam <NUM>) that traverse an optical path (e.g., the optical path <NUM> and the optical path <NUM>) are not illustrated for clarity.

A configuration <NUM> illustrates a beam splitter <NUM> that is a relatively thin (e.g., <NUM> micron to <NUM> 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 patient <NUM> being viewed by the healthcare provider <NUM> using the device <NUM>) or intermediate image plane is located at a finite distance from the beam splitter <NUM>. In a finite conjugate application, light is reflected from both the front and rear surface onto an image sensor <NUM>. For example, light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> is reflected from a first surface <NUM> of the beam splitter <NUM> to the image sensor <NUM>, and the second beam <NUM> is reflected from the first surface <NUM> of the beam splitter, to a second surface <NUM> of the beam splitter, and then to the image sensor <NUM>. A lens <NUM> may be configured between the beam splitter <NUM> and the image sensor <NUM> to focus the first beam <NUM> and the second beam <NUM> on the image sensor <NUM>.

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

A configuration <NUM> illustrates a beam splitter <NUM> that is a relatively thick (e.g., <NUM> millimeters to <NUM> millimeters) parallel plate, which is also configured for a finite conjugate application. Similar to the discussion above, light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> is reflected from a first surface <NUM> of the beam splitter <NUM> to an image sensor <NUM>. However, the second beam <NUM> is reflected from the first surface <NUM> of the beam splitter, to a second surface <NUM> of the beam splitter, and then away from a lens <NUM> and the image sensor <NUM>, such as to a beam dump <NUM>. Directing the second beam <NUM> away from the lens <NUM> and the image sensor <NUM> may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter <NUM> and the image sensor <NUM> are housed.

A configuration <NUM> illustrates a beam splitter <NUM> that is a relatively thick (e.g., <NUM> millimeters to <NUM> millimeters) parallel plate, which is also configured for a finite conjugate application. Similar to the discussion above, light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> in this example is reflected from a first surface <NUM> of the beam splitter <NUM> to a beam dump <NUM>. Additionally, the second beam <NUM> is reflected from the first surface <NUM> of the beam splitter <NUM>, to a second surface <NUM> of the beam splitter, and then towards an image sensor <NUM> by way of a lens <NUM>. Directing the first beam <NUM> away from the lens <NUM> and the image sensor <NUM> may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter <NUM> and the image sensor <NUM> are housed.

A configuration <NUM> illustrates a beam splitter <NUM> that 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 patient <NUM> being viewed by the healthcare provider <NUM> using the device <NUM>) is located at an infinite distance from the beam splitter <NUM>. If an intermediate image plane is present in the infinite conjugate application, a collimating lens <NUM> is 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 splitter <NUM> onto an image sensor <NUM>. For example, light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> is reflected from a first surface <NUM> of the beam splitter <NUM> to the image sensor <NUM>, and the second beam <NUM> is reflected from the first surface <NUM> of the beam splitter, to a second surface <NUM> of the beam splitter, and then to the image sensor <NUM>. A lens <NUM> may be configured between the beam splitter <NUM> and the image sensor <NUM> to focus the first beam <NUM> and the second beam <NUM> on the image sensor <NUM>.

Unlike the configuration <NUM> that included a finite conjugate application, the configuration <NUM> the first beam <NUM> and the second beam <NUM> converge and overlap on the image sensor <NUM>. Consequently, there is no image shift between the first beam <NUM> and the second beam <NUM>, and the thickness of the beam splitter <NUM> does not affect the image quality of the image created by the image sensor <NUM>. Thus, effects such as chromatic aberration and/or ghost images may be avoided in the configuration <NUM>.

<FIG> is a schematic illustration <NUM> of additional beam splitter configurations that may be used in a visual observation tool in accordance with examples of the present disclosure. The schematic illustration <NUM> includes beam splitter configurations in which the beam splitter is a wedge plate having two surfaces that are at an angle greater than <NUM> degrees and less than <NUM> degrees relative to one another (e.g., not parallel to one another). The beam splitters in the schematic illustration <NUM> may 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 provider <NUM> when performing manual viewing using the device <NUM>. 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 device <NUM> to be viewed by the healthcare provider <NUM>.

For example, a configuration <NUM> illustrates a beam splitter <NUM> that is configured as a wedge plate. Light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> in this example is reflected from a first surface <NUM> of the beam splitter <NUM> to an image sensor <NUM> via a lens <NUM>. The second beam <NUM> is reflected from the first surface <NUM> of the beam splitter <NUM>, to a second surface <NUM> of the beam splitter, to a reverse side <NUM> of the first surface <NUM> of the beam splitter. The reverse side <NUM> of the first surface <NUM> of the beam splitter <NUM> directs the second beam <NUM> to a beam dump <NUM>. The beam dump <NUM> in the configuration <NUM> may be on a different side of the beam splitter <NUM> from which the light <NUM> originated. Directing the second beam <NUM> away from the lens <NUM> and the image sensor <NUM> may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter <NUM> and the image sensor <NUM> are housed.

A configuration <NUM> illustrates a beam splitter <NUM> that is also configured as a wedge plate. Light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> in this example is reflected from a first surface <NUM> of the beam splitter <NUM> to an image sensor <NUM> via a lens <NUM>. The second beam <NUM> is reflected from the first surface <NUM> of the beam splitter <NUM>, to a second surface <NUM> of the beam splitter, and then to a beam dump <NUM>. The beam dump in the configuration <NUM> may be on a same side of the beam splitter <NUM> from which the light <NUM> originated. Similar to the discussion above, directing the second beam <NUM> away from the lens <NUM> and the image sensor <NUM> may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter <NUM> and the image sensor <NUM> are housed.

Additionally, a configuration <NUM> illustrates a beam splitter <NUM> that is configured as a wedge plate. Light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> in this example is reflected from a first surface <NUM> of the beam splitter <NUM> to a beam dump <NUM> on a same side of the beam splitter <NUM> from which the light <NUM> originated. The second beam <NUM> is reflected from the first surface <NUM> of the beam splitter <NUM>, to a second surface <NUM> of the beam splitter, to a reverse side <NUM> of the first surface <NUM> of the beam splitter. The reverse side <NUM> of the first surface <NUM> of the beam splitter <NUM> directs the second beam <NUM> to an image sensor <NUM> via a lens <NUM>. Similar to the discussion above, directing the first beam <NUM> away from the lens <NUM> and the image sensor <NUM> may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter <NUM> and the image sensor <NUM> are housed.

A configuration <NUM> illustrates a beam splitter <NUM> that is also configured as a wedge plate. Light <NUM> impinging upon the beam splitter <NUM> is split into a first beam <NUM> and a second beam <NUM>. The first beam <NUM> in this example is reflected from a first surface <NUM> of the beam splitter <NUM> to a beam dump <NUM> on a different side of the beam splitter <NUM> from which the light <NUM> originated. The second beam <NUM> is reflected from the first surface <NUM> of the beam splitter <NUM>, to a second surface <NUM> of the beam splitter, to a reverse side <NUM> of the first surface <NUM> of the beam splitter. The reverse side <NUM> of the first surface <NUM> of the beam splitter <NUM> directs the second beam <NUM> to an image sensor <NUM> via a lens <NUM>. Similar to the discussion above, directing the first beam <NUM> away from the lens <NUM> and the image sensor <NUM> may reduce reflections and/or scattering of light inside of the device or accessory in which the beam splitter <NUM> and the image sensor <NUM> are 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., <NUM> micron to <NUM> 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> illustrates configurations <NUM> for 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 sheet <NUM> includes an illumination polarizer <NUM> and a viewing polarizer <NUM> which are to be cut from the polarizer sheet <NUM> by a die cutter. The illumination polarizer <NUM> includes lines <NUM>(a) corresponding to a polarization direction of the polarizer sheet <NUM>. Additionally, the viewing polarizer <NUM> includes lines <NUM>(b) corresponding to the polarization direction of the polarizer sheet <NUM>. The lines <NUM>(a) and the lines <NUM>(b) (collectively, lines <NUM>) are in a same direction for both the illumination polarizer <NUM> and the viewing polarizer <NUM>. The lines <NUM> are also substantially parallel or perpendicular to lines <NUM>, which correspond to an orientation of the die cutter.

The illumination polarizer <NUM> also includes at least a tab <NUM> and a notch <NUM> that are used to orient the illumination polarizer <NUM> inside of a device in a desired orientation, and prevent the illumination polarizer <NUM> from being installed in the device in another orientation than the desired orientation. Similarly, the viewing polarizer <NUM> includes a tab <NUM> which may be used to orient the viewing polarizer <NUM> inside of the device in a desired orientation as well. When the illumination polarizer <NUM> and the viewing polarizer <NUM> are oriented in the device in the desired orientations using the tabs <NUM> and <NUM> and the notch <NUM>, the lines <NUM>(a) are perpendicular to the lines <NUM>(b), thus polarizing light entering the device.

A polarizer sheet <NUM> also includes an illumination polarizer <NUM> and a viewing polarizer <NUM> which are to be cut from the polarizer sheet <NUM> by a die cutter. The illumination polarizer <NUM> includes lines <NUM>(a) corresponding to a polarization direction of the polarizer sheet <NUM>. Additionally, the viewing polarizer <NUM> includes lines <NUM>(b) corresponding to the polarization direction of the polarizer sheet <NUM>. The lines <NUM>(a) and the lines <NUM>(b) (collectively, lines <NUM>) are in a same direction for both the illumination polarizer <NUM> and the viewing polarizer <NUM>. However, the lines <NUM> are not, in this case, substantially parallel or perpendicular to lines <NUM>, which correspond to an orientation of the die cutter. As noted above, the polarizer sheet <NUM> may be misaligned from the die cutter during manufacture of the illumination polarizer <NUM> and the viewing polarizer <NUM>.

However, the misalignment may be resolved by cutting the illumination polarizer <NUM> and the viewing polarizer <NUM> from the same polarizer sheet <NUM>, and using shapes of the illumination polarizer <NUM> and the viewing polarizer <NUM> to correctly orient these polarizers inside of a device. For instance, the illumination polarizer <NUM> includes at least a tab <NUM> and a notch <NUM> that are used to orient the illumination polarizer <NUM> inside of a device in a desired orientation, and prevent the illumination polarizer <NUM> from being installed in the device in another orientation than the desired orientation. Similarly, the viewing polarizer <NUM> includes a tab <NUM> which may be used to orient the viewing polarizer <NUM> inside of the device in a desired orientation as well. When the illumination polarizer <NUM> and the viewing polarizer <NUM> are oriented in the device in the desired orientations using the tabs <NUM> and <NUM> and the notch <NUM>, the lines <NUM>(a) are still perpendicular to the lines <NUM>(b), regardless of the misalignment of the die cutter relative to the polarizer sheet <NUM>. Accordingly, light entering the device is still polarized to correct glare and reflections, despite such misalignment.

<FIG> illustrates a cross-sectional view <NUM> of a portion of an example visual observation tool incorporating polarizers according to the present disclosure. The cross-sectional view <NUM> illustrates an ophthalmoscope <NUM> that 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 ophthalmoscope <NUM> includes an illumination polarizer <NUM> and a viewing polarizer <NUM>, similar to the discussion above in relation to <FIG>.

A pop-out view <NUM> illustrates an orientation of the illumination polarizer <NUM> inside of the ophthalmoscope <NUM>. The illumination polarizer <NUM> includes a tab <NUM> which may correspond to the tab <NUM> and/or the tab <NUM> of <FIG>. The illumination polarizer <NUM> also includes and a notch <NUM>, which may correspond to the notch <NUM> and/or the notch <NUM> of <FIG>. The tab <NUM> and the notch <NUM> provide a shape for the illumination polarizer <NUM> that ensures that the illumination polarizer <NUM> is oriented correctly inside an opening <NUM> of the ophthalmoscope <NUM>, and is prevented from being installed in another orientation other than the correct orientation.

Additionally, a pop-out view <NUM> illustrates an orientation of the viewing polarizer <NUM> inside of the ophthalmoscope <NUM>. The viewing polarizer <NUM> includes a tab <NUM> which may correspond to the tab <NUM> and/or the tab <NUM> of <FIG>. The tab <NUM> provides a shape for the viewing polarizer <NUM> that ensures that the viewing polarizer <NUM> is oriented correctly inside an opening <NUM> of the ophthalmoscope <NUM>, and is prevented from being installed in another orientation other than the correct orientation. Further, the orientations of the illumination polarizer <NUM> and the viewing polarizer <NUM> based on the shapes of the polarizers, in combination with being cut from a same polarizer sheet as described in relation to <FIG>, ensures that light <NUM> entering the ophthalmoscope <NUM> is polarized to reduce or eliminate reflections and glare.

<FIG> illustrates a flowchart outlining an example method <NUM> of manufacturing an accessory for a visual observation tool in accordance with the present disclosure. Such methods do not fall within the scope of the claimed subject-matter. In some examples, the method <NUM> may be performed by one or more computing devices configured to manufacture visual observation tools. Reference will be made throughout the discussion of the method <NUM> to <FIG>, <FIG>, <FIG>, and <FIG>, which show schematic illustrations of visual observation tools and/or beam splitters.

At operation <NUM>, the method of manufacture includes providing a coupling mechanism for removably attaching an accessory <NUM> and/or an accessory <NUM> to a device, such as an otoscope <NUM>, and ophthalmoscope <NUM>, 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 operation <NUM>, the method of manufacture includes providing an image sensor, such as the image sensor <NUM> and/or the image sensor <NUM>, 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 sensor <NUM> is included in the accessory <NUM>. The image sensor <NUM> may be in communication with the controller <NUM> comprising an image processor configured to receive signals and/or other inputs from the image sensor <NUM>, and use the signals from the image sensor <NUM> to form a visual image or video of the patient <NUM> based on the signal.

At operation <NUM>, the method of manufacture includes providing a beam splitter, such as the beam splitter <NUM> and/or the beam splitter <NUM>, where the beam splitter has a first surface and a second surface. The beam splitter <NUM> and/or the beam splitter <NUM> may take any one of a variety of configurations, such as the parallel plate configurations <NUM>, <NUM>, <NUM>, and/or <NUM> described in relation to <FIG>, the wedge plate configurations <NUM>, <NUM>, <NUM>, and/or <NUM> described in relation to <FIG>, a cube beam splitter, a beam splitter having a geometric coating, a prism, or the like.

At operation <NUM>, the method of manufacture includes configuring the beam splitter <NUM> in the accessory <NUM> such that light impinging upon the first surface is split into a first beam <NUM>, a second beam <NUM>, and a third beam (e.g., see <FIG> and <FIG>). At operation <NUM>, the method of manufacture includes configuring the beam splitter <NUM> in the accessory <NUM> such that the first beam <NUM> travels from a first opening <NUM> of the device to a second opening <NUM> of the device along an optical path <NUM> when the accessory <NUM> is attached to the device via the coupling mechanism. Configuring the beam splitter <NUM> in this way enables the healthcare provider <NUM> to perform a manual examination of the patient by viewing through the device.

At operation <NUM>, the method of manufacture includes configuring the beam splitter <NUM> in the accessory <NUM> such that the second beam <NUM> travels from the first surface of the beam splitter <NUM> to the image sensor <NUM>. Additionally, at operation <NUM>, the method of manufacture includes configuring the beam splitter <NUM> in the accessory <NUM> such that the third beam travels from the second surface of the beam splitter <NUM> to the image sensor <NUM> or a beam dump. For instance, the beam splitter <NUM> may be configured to direct the third beam to the image sensor <NUM> to reduce or eliminate visual effects in digital images or video such as ghosting or chromatic aberration. Alternatively or additionally, the beam splitter <NUM> may be configured to direct the third beam to a beam dump (e.g., see <FIG> and <FIG>) to reduce reflections and/or scattering of light in the internal space <NUM>.

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).

Claim 1:
An accessory (<NUM>, <NUM>) attachable to a housing (<NUM>, <NUM>) of a medical device (<NUM>, <NUM>, <NUM>), the accessory comprising:
an image sensor (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
a beam splitter (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having a first surface (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and a second surface (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein when the accessory is attached to the housing of the medical device, the first surface of the beam splitter is configured to receive light (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) via a first opening (<NUM>, <NUM>) of the housing, and the beam splitter is configured to split the light into at least a first beam (<NUM>, <NUM>), a second beam (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and a third beam (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), such that:
the first beam travels, from the first surface to a second opening (<NUM>, <NUM>) of the housing, along a first optical path (<NUM>, <NUM>) 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, and
the third beam is directed, from the first surface to the image sensor or a beam dump (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), along a third optical path extending from the first surface to the image sensor or the beam dump via the second surface, wherein:
directing the third beam to the image sensor along the third optical path includes directing the third beam from the second surface of the beam splitter to the image sensor such that:
the third beam converges and overlaps with the second beam on the image sensor, and
at least one of ghosting and chromatic aberration is eliminated in an image formed by the image sensor using the second beam and the third beam, and wherein:
directing the third beam to the beam dump along the third optical path includes directing the third beam from the second surface of the beam splitter to the beam dump such that reflections and / or scattering of light in an internal space of the housing can be reduced.