Patent Description:
Each of these physical assessment devices typically includes an instrument head that is releasably attached to the upper end of an instrument handle. The instrument head typically includes an illumination source and optics that enable a physician to view a medical target, such as an ear or eye, through an eyepiece. The instrument handle contains a power source that powers the illumination source and other components of the instrument head. Different instrument handles may include different power sources such as rechargeable batteries, disposable batteries, or may provide power from wall mounted transformers.

<CIT> discloses a physical assessment device in which an instrument head is provided for attachment to a plurality of instrument handles having different power profiles. The instrument head contains an illumination assembly including at least one LED as well as a drive circuit for detecting a power profile of an attached instrument handle and converting variable voltages received from the attached instrument handle to a constant current for powering the at least one LED based on the power profile. The instrument head enables use with a plurality of instrument handles, including those originally configured for use with only incandescent light sources.

<CIT> discloses an adapter for permitting a medical diagnostic instrument having an illumination source including at least one LED to be used with a power supply normally configured for use with a diagnostic instrument having at least one incandescent lamp as an illumination source. The adapter includes circuitry for compensating LED specific characteristics for permitting the power supply to be used with the LED.

<CIT> discloses a method for adjusting the brightness of at least one LED as a function of changing supply voltage provided to the at least one LED. The method being carried out by means of a control unit which is provided for electrically coupling the electrical supply device to the at least one LED. The method comprises the following steps: detecting a parameter which indicates the changing supply voltage; and depending on the detected parameter, providing a control voltage to the at least one LED to set an LED current in such a way that the at least one LED has a predefined relative brightness change over the predefined voltage range.

<CIT> discloses a lighting device with at least one LED which can be connected via a switching device to a voltage source. The voltage source is optionally formed by a battery unit or an accumulator unit. Depending on which contact device a voltage is applied to, the switching devce can detect whether a battery unit or rechargeable battery unit is being used as the voltage source.

In general terms, the present disclosure is directed to the field of diagnostic medicine and more specifically to an improved physical assessment device configured to perform diagnostic patient examinations. In certain examples, the physical assessment device is an otoscope, an ophthalmoscope, or other similar diagnostic device. Various aspects are described in this disclosure, which include, but are not limited to, the following aspects.

One aspect relates to an instrument head for attachment to a plurality of instrument handles having different power sources. The instrument head comprises at least one light-emitting diode; and a controller having one or more processing units and a memory storing instructions which, when executed by the one or more processing units, cause the controller to detect an instability in a voltage input from a power source in an instrument handle when attached to the instrument head, the voltage input powering the at least one light-emitting diode; and transition from a normal mode of operation to a mitigation mode of operation when the instability is detected, the mitigation mode of operation preventing an increase in output of the at least one light-emitting diode for a predetermined period of time.

Another aspect relates to a physical assessment device, comprising an instrument handle supplying a voltage input from a power source; and an instrument head attached to the instrument handle, the instrument head including: at least one light-emitting diode; and a controller having one or more processing units and a memory storing instructions which, when executed by the one or more processing units, cause the controller to: detect an instability of the voltage input from the power source; and transition from a normal mode of operation to a mitigation mode of operation in response to detecting the instability, the mitigation mode of operation preventing an increase in output of the at least one light-emitting diode.

Another aspect relates to a method of powering at least one light-emitting diode on an instrument head, the method comprising detecting an instability of a voltage input received from an instrument handle when attached to the instrument head, the voltage input powering the at least one light-emitting diode; transitioning from a first mode of operation to a second mode of operation in response to detecting the instability, the second mode of operation preventing an increase in output of the at least one light-emitting diode for a first predetermined period of time; detecting a rapid lowering of the voltage input; transitioning from the first mode of operation to a third mode of operation in response to detecting the rapid lowering, the third mode of operation allowing only a decrease in output of the at least one light-emitting diode for a second predetermined period of time; detecting that the voltage input is below a threshold amount; and transitioning from the first mode of operation to a fourth mode of operation in response to detecting that the voltage input is below the threshold amount, the fourth mode of operation disabling the at least one light-emitting diode for a third predetermined period of time.

<FIG> is an isometric view of a physical assessment device <NUM>. The physical assessment device <NUM> may share similar components with the physical assessment devices described in <CIT>, the entirety of which is hereby incorporated by reference.

In the example illustrated in <FIG>, the physical assessment device <NUM> is an otoscope. In other alternative examples, the physical assessment device <NUM> is an ophthalmoscope, a dermatoscope, or other type of physical assessment device.

The physical assessment device <NUM> includes an instrument head <NUM> that is releasably attached to the upper end of an instrument handle <NUM>. The instrument handle <NUM> is sized and shaped to permit the physical assessment device <NUM> to be handheld and is further configured to contain a power source for powering the instrument head <NUM>.

A light source of the instrument head <NUM> is energized by the instrument handle <NUM>. The illumination output of the light source is controlled by a rheostat <NUM>, which includes a twistable dial <NUM> formed on the instrument handle <NUM>. The twistable dial <NUM> can be twisted by the hand of the user to adjust the illumination output of the light source.

The power source can be recharged via a charging port <NUM>. In the example shown in <FIG>, the charging port <NUM> is provided on the bottom end of the instrument handle <NUM>.

<FIG> is a bottom isometric view of an instrument head. Referring now to <FIG> and <FIG>, the instrument head <NUM> includes a body housing having a distal patient end <NUM> and an opposing proximal caregiver end <NUM>. The interior of the instrument head <NUM> is sized and configured to retain a plurality of components. The physical assessment device <NUM> retains an optical assembly that includes a hollow lens tube containing a plurality of optical components that are supported within the interior of the instrument head <NUM>.

The instrument head <NUM> includes a pair of mated housing sections that include a front housing section <NUM> and a rear housing section <NUM>. Each of the front and rear housing sections <NUM>, <NUM> is a shell-like member made from a structural material, such as a moldable plastic. The front and rear housing sections <NUM>, <NUM> can be mated to one another using fasteners to define an interior cavity. Alternatively, the front and rear housing sections <NUM>, <NUM> can also be secured by welding, such as ultrasonic welding or other suitable means.

The lower ends of each of the front and rear housing sections <NUM>, <NUM> are retained at the bottom of the instrument head <NUM> using a securing ring <NUM>. According to this embodiment, a peripheral bumper <NUM> is disposed between the front and rear housing sections <NUM>, <NUM>. In some examples, the securing ring <NUM> can include a locking element, such as, for example, a pin that is insertable through a transverse opening <NUM> formed in the securing ring <NUM>.

A hollow speculum tip element, that is designed and shaped to fit a predetermined distance into the ear canal, can releasably attach to a distal ring member <NUM>. When attached, the hollow speculum tip element overlays a distal insertion portion <NUM> on the distal patient end <NUM>. The distal insertion portion <NUM> includes an optical window, and an objective lens is positioned adjacent the optical window inside the body housing of the instrument head <NUM>.

The opposing proximal caregiver end <NUM> includes an adapter interface member <NUM> that is configured to receive an adapter for attaching an external device to the instrument head <NUM>. In the example illustrated in <FIG>, the adapter interface member <NUM> includes machined flats <NUM> and spring loaded balls <NUM> that can provide a stable mounted platform for the adapter. The adapter interface member <NUM> can also include a brow rest <NUM>.

A bottom portion of the instrument head <NUM> includes a mechanical interface <NUM> and an electrical interface <NUM>. In the example shown in the figure, the mechanical interface <NUM> is a ring that can engage a corresponding mechanical interface on the instrument handle <NUM> to attach the instrument handle <NUM> to the instrument head <NUM>. In the example shown in the figure, the electrical interface <NUM> is a pin that can engage a corresponding electrical interface on the instrument handle <NUM> to provide an electrical connection with the instrument handle <NUM>.

Typically, instrument heads are compatible only with specific instrument handles. This is because instrument heads typically have distinct types of lighting assemblies that have different electrical requirements. For example, some types of instrument heads have light assemblies that are halogen lamp based. A halogen lamp filament becomes brighter when an input voltage increase, and the lamp filament dims when the input voltage decreases.

In contrast, other types of instrument heads have light assemblies that are light-emitting diode (LED) based. Varying voltage as a way of controlling illumination output is incompatible with LEDs. Instead, LED light dimming is achieved by a constant current that is pulse-width modulated to reduce the duty time that the LED is on.

In addition, traditional instrument handles may include alternating current (AC) power sources, and may only be compatible with lighting that can use AC power, such as incandescent or halogen lighting. Further, different instrument handles may be wired with different polarities, requiring the instrument heads to be hardwired to accept the specific polarity. LED drive circuits have strict requirements for polarity. Current instrument handles have multiple polarities (+/-, -/+ and a variation of AC), and therefore the input power must be rectified to a single polarity before an LED in the instrument head can be driven.

Thus, instrument handles are typically designed to provide electrical power in a specific voltage profile and current based on the requirements of the light assemblies provided on the instrument heads. Accordingly, instrument heads are not typically usable with different instrument handles, requiring a proliferation of instrument heads and handles.

The following description relates to software control and algorithms that allow compatibility between different instrument heads and instrument handles. More specifically, the software control and algorithms are implemented on the instrument head <NUM> to adapt the instrument head <NUM> to be compatible with distinct types of instrument handles. The software control allows the instrument head <NUM> to be compatible with instrument handles designed for powering halogen lamps and with instrument handles designed for powering LEDs.

<FIG> schematically illustrates the physical assessment device <NUM>. As discussed above, the physical assessment device <NUM> includes the instrument handle <NUM> and the instrument head <NUM>. The instrument handle <NUM> includes the rheostat <NUM>, and a power source <NUM>. The power source <NUM> can include one or more rechargeable batteries or disposable batteries, or can be acquired from a <NUM>-volt power outlet or from a Universal Serial Bus (USB) connector. The rheostat <NUM> can be operated by a user to control the current from the power source <NUM>.

The instrument handle <NUM> includes a mechanical interface <NUM> that can releasably attach to the mechanical interface <NUM> of the instrument head <NUM> to fix the instrument handle <NUM> to the instrument head <NUM>. Thus, a user can grasp the instrument handle <NUM> with the instrument head <NUM> attached thereto to perform an otoscopic or ophthalmic examination. In some examples, the mechanical interface <NUM> also provides grounding.

The instrument handle <NUM> further includes an electrical interface <NUM> that interfaces with the electrical interface <NUM> of the instrument head <NUM> to supply a voltage from the power source <NUM> to the instrument head <NUM>. As will be described in more detail, the voltage from the instrument handle <NUM> is supplied to the instrument head <NUM> to power one or more components of the instrument head <NUM> including a light assembly having at least one LED <NUM>.

As shown in <FIG>, the instrument head <NUM> includes a controller <NUM> which includes a first analog-to-digital-converter <NUM> and a second analog-to-digital converter <NUM> that both receive the voltage supplied from the power source <NUM> via the connection between the electrical interface <NUM> and electrical interface <NUM>. The first and second analog-to-digital converters <NUM>, <NUM> convert the voltage into separate, independent signals that are readable by the controller <NUM>.

The controller <NUM> can use the separate, independent signals from the first and second analog-to-digital converters <NUM>, <NUM> to detect voltage input instabilities from the power source <NUM>. For example, one signal is dampened to change slowly over time while the other signal is not. The controller <NUM> can compare the two signals to determine whether there is an instability in the voltage input received by the instrument head <NUM> from the instrument handle <NUM>.

The controller <NUM> includes an LED enabler <NUM> and a pulse-width-modulation (PWM) driver <NUM> that allow the controller <NUM> to control the illumination output of the at least one LED <NUM>. The controller <NUM> also includes a load resistor <NUM>. As will be described in more detail, the load resistor <NUM> can be used by the controller <NUM> to increase the current drawn from the power source <NUM> in the instrument handle <NUM> to help stabilize the power source <NUM> in the instrument handle when a voltage input instability is detected.

<FIG> illustrates a method <NUM> for identifying the instrument handle <NUM> when attached to the instrument head <NUM> of the physical assessment device <NUM>. Referring now to <FIG>, the method <NUM> includes an operation <NUM> that determines whether the polarity of the voltage from the power source <NUM> in the instrument handle is negative or positive.

When the polarity is determined in operation <NUM> to be negative, the method <NUM> proceeds to an operation <NUM> of determining whether the power profile of the power source <NUM> is linear or curved (i.e., exponential). When the power profile is determined to be linear, a first type of instrument handle <NUM> is identified (i.e., an instrument handle having a power source with a negative polarity and a linear power profile). When the power profile is determined to be curved, a second type of instrument handle <NUM> is identified (i.e., an instrument handle having a power source with a negative polarity and a curved power profile).

When the polarity is determined in operation <NUM> to be positive, the method <NUM> proceeds to an operation <NUM> of determining whether the power profile of the power source <NUM> is linear or curved (i.e., exponential). When the power profile is determined to be linear, a third type of instrument handle <NUM> is identified (i.e., an instrument handle having a power source with a positive polarity and a linear power profile).

When the power profile is determined in operation <NUM> to be curved, the method <NUM> proceeds to an operation <NUM> of determining whether a first characteristic is present in the power profile of the power source <NUM>. In some examples, the first characteristic is a specific voltage signature. As an illustrative example, the voltage signature relates to how the voltage rises to a predetermined level of voltage. When the first characteristic is determined in operation <NUM> to be present, a fourth type of instrument handle <NUM> is identified (i.e., an instrument handle having a power source with a positive polarity, a curved power profile, and the first characteristic).

When the first characteristic is not determined in operation <NUM> to be present in the power profile, the method <NUM> proceeds to an operation <NUM> of determining whether a second characteristic is present in the power profile of the power source <NUM>. In some examples, the second characteristic is a pulsed signal that is pulse-width-modulated.

When the second characteristic is determined in operation <NUM> to be present, a fifth type of instrument handle <NUM> is identified (i.e., an instrument handle having a power source with a positive polarity, a curved power profile, and the first characteristic). When the second characteristic is not determined in operation <NUM> to be present, a sixth type of instrument handle <NUM> is identified (i.e., an instrument handle having a power source with a positive polarity, a curved power profile, and that does not have the first or second characteristics).

<FIG> schematically illustrates an algorithm <NUM> for operating the instrument head <NUM> after the instrument handle <NUM> has been identified from completion of the method <NUM>. The algorithm <NUM> is performed by the controller <NUM> of the instrument head <NUM> (see <FIG>) to apply control and scaling appropriate to the identified instrument handle. The algorithm <NUM> can be performed to dim the at least one LED <NUM> (see <FIG>) proportionally with a user input using only power and return signals maintaining legacy compatibility. In this regard, the ability to identify the instrument handle connected to the instrument head <NUM> (by performing the method <NUM>) enables the controller <NUM> to smoothly and proportionally dim the at least one LED <NUM>. Additionally, the algorithm <NUM> mitigates stability problems and implements error correction. Thus, the algorithm <NUM> can mitigate instability for illuminating the at least one LED <NUM>.

Incandescent or halogen bulbs draw a large amount of current whereas the at least one LED <NUM> does not. Thus, legacy instrument handles that are designed to power incandescent or halogen bulbs can sometimes provide an unstable voltage when powering the at least one LED <NUM>. For example, the voltage input from legacy instrument handles can fluctuate which can cause the illumination output from the at least one LED <NUM> to flicker.

Referring now to <FIG>, a normal mode of operation <NUM> is performed by the controller <NUM> to operate the at least one LED <NUM>. The normal mode of operation <NUM> allows the at least one LED <NUM> to operate under predefined conditions that are designed to mitigate instability. As an example, the predefined conditions can include increasing or decreasing the illumination output of the at least one LED <NUM> by about <NUM>% in about <NUM> milliseconds. In some examples, normal mode of operation <NUM> disables the load resistor <NUM> (see <FIG>).

When an instability of the voltage received from the instrument handle <NUM> is detected, the controller <NUM> transitions from the normal mode of operation <NUM> to a mitigation mode of operation <NUM>. The mitigation mode of operation <NUM> prevents an increase in illumination output of the at least one LED <NUM> for a predetermined period of time. In some examples, the mitigation mode of operation <NUM> lowers the illumination output of the at least one LED <NUM>. In the mitigation mode of operation <NUM>, the controller <NUM> controls the illumination output of the at least one LED <NUM> by controlling the PWM driver <NUM>.

The mitigation mode of operation <NUM> can also enable the load resistor <NUM> (see <FIG>) to increase the current being drawn from the power source <NUM> in the instrument handle <NUM>. Advantageously, this can help to stabilize the power source <NUM> in the instrument handle <NUM> by imitating the current draw of a typical incandescent or halogen bulb.

In some examples, the predetermined period of time is about <NUM> milliseconds. After the predetermined period of time expires or once the power source <NUM> is detected as stable, the controller <NUM> transitions from the mitigation mode of operation <NUM> to the normal mode of operation <NUM>. Advantageously, by identifying instabilities and switching back and forth between the normal mode of operation <NUM> and the mitigation mode of operation <NUM>, the algorithm <NUM> can maintain a consistent illumination output and mitigate the flickering of the at least one LED.

The controller <NUM> can also switch from the normal mode of operation <NUM> to a rapid lowering mode of operation <NUM> to control the operation of the at least one LED <NUM>. The rapid lowering mode of operation <NUM> is performed when the input voltage from the power source <NUM> is detected as decreasing faster than a predetermined threshold rate. The rapid decrease in the input voltage can be due to an instability from the power source <NUM>.

In the rapid lowering mode of operation <NUM>, the controller <NUM> allows the illumination output of the at least one LED <NUM> to decrease, and prevents the illumination output of the at least one LED <NUM> from increasing. The rapid lowering mode of operation <NUM> can be performed for a predetermined period of time. In some examples, the predetermined period of time is about <NUM> milliseconds. After the predetermined period of time expires or once the input voltage from the power source <NUM> is no longer detected as rapidly decreasing, the controller <NUM> transitions from the rapid lowering mode of operation <NUM> back to the normal mode of operation <NUM> to control the operation of the at least one LED <NUM>.

The controller <NUM> can also transition from the rapid lowering mode of operation <NUM> to the mitigation mode of operation <NUM> when a further instability of the voltage input from the instrument handle is detected. The controller <NUM> can transition from the mitigation mode of operation <NUM> back to the rapid lowering mode of operation <NUM>. Alternatively, the controller <NUM> can transition from the mitigation mode of operation <NUM> to the normal mode of operation <NUM>.

The controller <NUM> can also switch from the normal mode of operation <NUM> to a disable mode of operation <NUM> to control the operation of the at least one LED <NUM>. The disable mode of operation <NUM> is performed when the voltage input from the power source <NUM> is detected as being below a predetermined threshold amount. The low voltage input can affect the stability of the constant current supplied from the PWM driver <NUM> to the at least one LED <NUM>.

In the disable mode of operation <NUM>, the controller <NUM> disables the at least one LED <NUM> for a predetermined period of time. In some examples, the predetermined period of time is about <NUM> milliseconds. After the predetermined period of time expires or when the voltage input from the power source <NUM> is above the predetermined threshold amount, the controller <NUM> transitions from the disable mode of operation <NUM> to the normal mode of operation <NUM>.

In addition to the foregoing, the controller <NUM> can in some instances transition from the rapid lowering mode of operation <NUM> to the disable mode of operation <NUM> when the voltage input from the power source <NUM> is detected as being below the predetermined threshold amount. Thereafter, the controller <NUM> transitions from the disable mode of operation <NUM> to the normal mode of operation <NUM> when after a predetermine period of time (e.g., <NUM> milliseconds) or when the voltage input from the power source <NUM> is above the predetermined threshold amount.

<FIG> schematically illustrates an example of the controller <NUM> that can be used by the instrument head <NUM> to implement aspects and features described above. In some instances, the controller <NUM> is a microprocessor or microcontroller. The controller <NUM> includes one or more processing units <NUM>, a system memory <NUM>, and a system bus <NUM> that couples the system memory <NUM> to the processing unit <NUM>.

The one or more processing units <NUM> are examples of processing devices such as central processing units (CPUs). The system memory <NUM> includes a random-access memory ("RAM") <NUM> and a read-only memory ("ROM") <NUM>. A basic input/output logic having basic routines that help to transfer information between elements within the controller <NUM>, such as during startup, is stored in the ROM <NUM>.

The controller <NUM> can include a mass storage device <NUM> that is able to store software instructions and data. The mass storage device <NUM> is connected to the one or more processing units <NUM> through a mass storage controller connected to the system bus <NUM>. The mass storage device <NUM> and its associated computer-readable data storage media provide non-volatile, non-transitory storage for the controller <NUM>.

Although the description of computer-readable data storage media contained herein refers to a mass storage device, it should be appreciated by those skilled in the art that computer-readable data storage media can be any available non-transitory, physical device or article of manufacture from which the device can read data and/or instructions. In certain embodiments, the computer-readable storage media comprises entirely non-transitory media. The mass storage device <NUM> is an example of a computer-readable storage device.

Computer-readable data storage media include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable software instructions, data structures, program modules or other data. Example types of computer-readable data storage media include, but are not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid-state memory technology, or any other medium which can be used to store information, and which can be accessed by the device.

The controller <NUM> can operate in a networked environment using logical connections through a network interface unit <NUM> connected to the system bus <NUM>. The network interface unit <NUM> may connect to diverse types of communications networks and devices.

The controller <NUM> can also include an input/output unit <NUM> that allows the controller to receive and process inputs and outputs from a number of external devices.

Claim 1:
An instrument head (<NUM>) for attachment to a plurality of instrument handles (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having different power sources (<NUM>), the instrument head (<NUM>) comprising:
at least one light-emitting diode (<NUM>); and
a controller (<NUM>) having one or more processing units (<NUM>) and a memory storing instructions;
characterised in that
said instructions, when executed by the one or more processing units (<NUM>), cause the controller to:
detect an instability in a voltage input from a power source (<NUM>) in an instrument handle (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) when attached to the instrument head (<NUM>), the voltage input powering the at least one light-emitting diode (<NUM>); and
transition from a normal mode of operation (<NUM>) to a mitigation mode of operation (<NUM>) when the instability is detected, the mitigation mode of operation (<NUM>) preventing an increase in output of the at least one light-emitting diode (<NUM>) for a predetermined period of time.