A method for identifying the characteristics of optical paths corresponding to fluid pathways in medical devices.

Abstract

A system 100 is disclosed that is configured to identify a characteristic, such as the amount of obstruction and / or health / disruption, of an optical pathway 104 corresponding to a fluid pathway of a medical device. Identifying the characteristic includes increasing a current input to a light emitting element LEE 108 for a time period beginning at a first time point, receiving an output of the LEE via the optical pathway during the time period by a light detecting element 112, converting the output of the LEE to a voltage output during the time period, identifying a second time point within the time period at which the voltage output exceeds a threshold, and identifying a characteristic of the optical pathway between the LEE and the light detecting element based on a difference between the second time point and the first time point.

Description

Technical Field

[0001] Priority Claim This application claims priority to U.S. Provisional Patent Application No. 63 / 152,427, filed on February 23, 2021, by inventor Christopher Carl Jung, entitled "SELF-CHECKING PHOTOELECTRIC SENSOR AND METHOD OF OPERATION", the entire content of which is incorporated herein by reference as if fully set forth herein.

[0002] The present disclosure generally relates to a self-checking photoelectric sensor configured to identify characteristics of an optical path (e.g., an electro-optical path), such as blockage amount, health / deterioration over time, etc.

Background Art

[0003] Photoelectric sensors can be used to confirm the presence (or absence) of an object using a light transmitter (e.g., emitting infrared or visible light, such as a light-emitting diode (LED)) and a photodetector. Photoelectric sensors can be implemented in various situations to identify the presence or absence of an obstacle. For example, a photoelectric sensor can be implemented within a path (e.g., a fluid path) to identify whether the path is blocked or obstructed.

[0004] In one example, a photoelectric sensor can be implemented within the fluid path of a vitreoretinal treatment unit to assist in monitoring the quality of the fluid path during treatment. That is, as an advantage, it can detect any form of blockage, such as fluid clogging, aspirated tissue, or other blockages within the path. Further, a photoelectric sensor implemented within such a system can also be used to indicate the overall health / cleanliness of the light transmitter and / or receiver and to warn the sensor system itself if there is any deterioration.

[0005] Vitreoretinal procedures can include a variety of surgical procedures performed to restore, maintain, and improve vision. Vitreoretinal procedures may be appropriate for treating many serious conditions of the posterior part of the eye. Vitreoretinal procedures can treat conditions such as age-related macular degeneration (AMD), diabetic retinopathy and diabetic vitreous hemorrhage, macular holes, retinal detachment, epiretinal membranes, cytomegalovirus (CMV) retinitis, and many other ophthalmic conditions. In vitreoretinal procedures, a handheld unit is plugged into a port on a base unit that can, for example, monitor fluid pathways during surgery. [Overview of the project] [Means for solving the problem]

[0006] This disclosure generally relates to a self-checking photoelectric sensor configured to identify the characteristics of an optical path.

[0007] A particular embodiment provides a method for determining the characteristics of an optical path. This method generally includes increasing the current input to a light-emitting element (LEE) over a period of time starting from a first time point. This method generally includes receiving the output of the LEE through the optical path during that period using a photodetector. This method generally includes converting the output of the LEE into a voltage output during that period. This method generally includes identifying a second time point during that period when the voltage output exceeds a threshold. This method generally includes determining the characteristics of the optical path between the LEE and the photodetector based on the difference between the second time point and the first time point.

[0008] A particular embodiment provides a method for determining the characteristics of an optical path. This method generally includes emitting an optical output from a LEE over a period beginning at a first time point. This method generally includes receiving the output of the LEE through the optical path during that period using a photodetector. This method generally includes converting the output of the LEE into a voltage output during that period. This method generally includes changing the voltage output by changing the gain of an amplifier coupled to the voltage output during that period. This method generally includes identifying a second time point during that period when the voltage output exceeds a threshold. This method generally includes determining the characteristics of the optical path between the LEE and the photodetector based on the difference between the second time point and the first time point.

[0009] A particular embodiment provides a method for determining the characteristics of an optical path. This method generally includes applying a first current input to a LEE. This method generally includes a photodetector receiving the output of the LEE via the optical path while the first current input is applied to the LEE. This method generally includes converting the output of the LEE into a voltage output. This method generally includes determining whether the voltage output is greater than a first threshold. This method generally includes applying a second current input to the LEE if the voltage output is greater than the first threshold. This method generally includes receiving the output of the LEE via the optical path while the second current input is applied to the LEE, if the voltage output is greater than the first threshold. This method generally includes converting the output of the LEE into another voltage output if the voltage output is greater than the first threshold. This method generally includes determining whether the other voltage is greater than a second threshold if the voltage output is greater than the first threshold, where the second current is lower than the first current and the second threshold is lower than the first threshold. This method generally involves determining the characteristics of an optical path based on whether the other voltage output is greater than a second output when the voltage input is greater than a first threshold.

[0010] A particular embodiment provides a method for determining the characteristics of an optical path. This method generally includes applying a current input to a LEE. This method generally includes a photodetector receiving the output of the LEE via the optical path while the current input is applied to the LEE. This method generally includes converting the LEE output to a voltage output while an amplifier coupled to the LEE is configured with a first gain. This method generally includes determining whether the voltage output is greater than a first threshold. This method generally includes applying a current input to the LEE while the amplifier is configured with a second gain if the voltage output is greater than the first threshold. This method generally includes receiving the output of the LEE via the optical path while the current input is applied to the LEE and the amplifier is configured with a second gain if the voltage output is greater than the first threshold. This method generally includes converting the LEE output to another voltage output if the voltage output is greater than the first threshold. This method generally involves determining whether other voltage outputs are greater than a second threshold when a voltage output is greater than a first threshold, where the second gain is lower than the first gain and the second threshold is lower than the first threshold. This method generally involves determining the characteristics of an optical path based on whether other voltage outputs are greater than a second threshold when a voltage output is greater than a first threshold.

[0011] Aspects of this disclosure provide means, apparatus, processors, and computer-readable media for carrying out the methods and techniques described herein.

[0012] The following description and related drawings detail specific exemplary features of one or more embodiments.

[0013] The accompanying drawings illustrate only examples of specific embodiments of the present disclosure and should therefore not be considered to limit the scope of the present disclosure. [Brief explanation of the drawing]

[0014] [Figure 1]A block diagram of an exemplary system configured to specify the characteristics of an optical path according to a particular embodiment is shown. [Figure 2] A schematic diagram of the "ports" of five pneumatic connectors or pneumatic modules according to a specific embodiment is shown. [Figure 3A-3C] The diagrams show various timings associated with the voltage levels and / or various gains of the circuit input or the output of a light-emitting diode (LED) according to a specific embodiment. [Figure 4] A flowchart illustrating exemplary operations for identifying the characteristics of the optical path according to a specific embodiment is shown. [Figure 5] Other flowcharts illustrating exemplary operations for identifying the characteristics of the optical path according to a specific embodiment are shown. [Figure 6] Other flowcharts illustrating exemplary operations for identifying the characteristics of the optical path according to a specific embodiment are shown. [Figure 7] Another flowchart illustrating exemplary operations for identifying the characteristics of the optical path according to a specific embodiment is shown. [Figure 8A-8B] An exemplary circuit diagram according to a specific embodiment is shown. [Figure 9] A surgical console for a pneumatic ophthalmic surgical machine according to a specific embodiment is shown. [Figure 10A-10B] A schematic diagram of a pneumatic system for a pneumatic vitrectomy machine according to a specific embodiment is shown. [Figure 11] This shows a cutting device for a surgical probe according to a specific embodiment. [Modes for carrying out the invention]

[0015] To facilitate understanding, the same reference numerals are used whenever possible to indicate identical elements common to each drawing. Elements and features of one embodiment are intended to be usefully incorporated into other embodiments without further explanation.

[0016] Certain aspects provide mechanisms and techniques for identifying one or more characteristics of an optical path. For example, such techniques can be used to identify whether there is an obstruction within the optical path and / or to indicate the overall integrity of the optical path (e.g., the amount of degradation due to aging, ambient temperature effects, etc.). In some cases, the optical path can correspond to the fluid path of a port within a pneumatic ophthalmic surgical machine (e.g., during a vitreoretinal procedure). Although certain aspects are described within the context of a pneumatic ophthalmic surgical machine, it should be understood that the techniques described herein can be used to identify one or more characteristics of any suitable optical path.

[0017] In certain aspects, the transmitter and receiver circuit configurations of a photo-sensor system can be configured to perform a photoelectric detection of an obstruction within the optical path (e.g., detection at a console port, which can be referred to as port detection) to provide a reading of the integrity of the optical path. That is, the transmitter circuit configuration can be configured to generate an optical output that would be emitted through the optical path, and the receiver circuit configuration can be configured to receive the emitted light and generate a voltage output corresponding to the received light. In this case, the intensity of the received light is based on the amount of obstruction within the optical path, and as the amount of obstruction increases, the intensity of the received light beam decreases. Thus, as the amount of obstruction increases, the voltage output generated by the receiver circuit configuration decreases. Although certain aspects are described herein where an LED generates the optical output and a photodiode receives the optical output, it should be noted that other suitable components can be used as well.

[0018] In the implementation of some photoelectric sensors (regardless of whether they are light-blocking type or reflection type), the ratio of the analog signal (or voltage) output level in the receiver circuit configuration between when there is a detection target (e.g., occlusion) in the optical path between the transmitter and the receiver and when there is no detection target in that optical path is relatively high. For example, at a certain LED current level, a high ratio between when there is occlusion and when there is not (e.g., a 200:1 based on voltages of 20V (volts) and 0.1V) can help accurately distinguish whether the path is actually occluded or open. In other words, the voltage output level at the receiver when there is no occlusion in the path can be, for example, 200 times the voltage output level at the receiver when the path is occluded. This high ratio is desirable because physical aspects of the photoelectric sensor (e.g., LED degradation, misalignment of the optical system, and / or clouding of the optical system) can cause fluctuations in the LED output regardless of the occlusion in the optical path between the receiver and the transmitter. However, although the high signal ratio is beneficial, the voltage output level can still vary significantly over a relatively wide voltage range that can exceed the saturation voltage (e.g., 12V) of the amplifier in the receiver. Therefore, some voltage outputs at the receiver indicating no occlusion in the path can be clipped at this saturation voltage. In this situation, the integrity of the entire optical path cannot be completely and accurately specified. This is because even though based on the output voltage at the receiver for a specific current level input to the LED in the transmitter, the optical path may seem to have no occlusion, there may still be a certain degree of occlusion that is not indicated by the output voltage level of the photoelectric sensor otherwise.

[0019] Therefore, in certain aspects, the transmitter and receiver circuit configurations described herein are configured to identify the characteristics of the optical path by performing photoelectric detection using the voltage output level in the receiver circuit configuration while adjusting one or more of the gain in the receiver circuit configuration or the current input to the LED in the transmitter circuit configuration. For example, certain aspects can provide, as an advantage, a method for more accurately reading the integrity of the optical path.

[0020] In a particular embodiment, during a period beginning at a first time point, light may be emitted from the LED through the optical path, increasing in intensity based on the increasing current input to the LED. The light output is received and converted into a voltage output, and a second time point can be identified during which the voltage output exceeds a threshold. The characteristics of the optical path (e.g., the amount of blockage and / or the health of the LED and the photodiode receiving the LED light output) can then be identified based on the difference between the first and second time points.

[0021] In a particular embodiment, light may be emitted from the LED through the optical path (for example, based on a constant power input to the LED) during a period beginning from a first time point. The light is received and converted into a voltage output that varies with the gain of an amplifier, and a second time point can be identified during that period when the voltage output exceeds a threshold. The characteristics of the optical path (e.g., the amount of blockage and / or the health of the LED and the photodiode receiving the LED light output) can then be identified based on the difference between the first and second time points.

[0022] In certain embodiments, a current input may be applied to an LED, the LED output may be received and converted into a voltage output. It may be determined whether the voltage output is higher than a first threshold, and if it is, a different current input (e.g., lower than the first current input) may be applied to the LED for light emission and light reception / conversion. It may then be determined whether the voltage output is higher than a different threshold (e.g., lower than the first threshold), and the characteristics of the optical path may be determined based on whether the voltage output is higher than a second threshold.

[0023] In certain embodiments, a current input can be applied to the LED, and while the amplifier of the receiver is configured with a first gain, the output of the LED can be received and converted to a voltage output. It can be determined whether the voltage output is higher than a first threshold. If the voltage output is higher than the first threshold, a current input can be applied to the LED, and while the amplifier is configured with a different gain (e.g., lower than the first gain), the output from the LED can be received and converted to a voltage output. Then, it can be determined whether the voltage output is higher than a different threshold (e.g., lower than the first threshold), and the characteristics of the optical path can be determined based on whether the voltage output is higher than a second threshold.

[0024] In some embodiments, the methods described herein can be implemented in a pneumatic ophthalmic surgical machine to perform port detection. More generally, the aspects described herein can be used in any optoelectronic sensor application where it is desirable to monitor not only the actual detection of an item (e.g., occlusion) but also the quality of the overall sensor path and possible degradation that can occur in the sensor path (e.g., having an electronic circuit, optical elements, etc.).

[0025] The features of the invention may be described with respect to specific embodiments and the following drawings, but all embodiments of the invention can include one or more of the advantageous features described herein. In other words, while one or more embodiments may be described as having certain advantageous features, one or more of such features can be used in accordance with various other embodiments described herein. Similarly, while exemplary embodiments may be described below as embodiments of a device, apparatus, or method, it should be understood that such exemplary embodiments can be implemented in various devices, apparatuses, and methods.

[0026] Exemplary LED Detection Circuit and Operating Method Certain embodiments of this disclosure provide a method for determining whether an optical path is blocked. In certain embodiments, the circuit described herein may be implemented in a pneumatic ophthalmic surgical machine for performing port detection. More generally, the embodiments, methods, and techniques described herein may be used in any photoelectric sensor application where it is desirable to monitor the quality of the entire sensor path (e.g., having electronic circuits, optical elements, etc.) as well as the actual detection of a particular item (e.g., blockage).

[0027] As mentioned above, a high signal ratio between the receiver voltage output indicating no blockage and the voltage output indicating blockage in the optical path can be beneficial, but it can reach and even exceed the amplifier's saturation voltage (e.g., 12V) due to a relatively wide range of possible voltage outputs. Therefore, some of the receiver voltage outputs indicating no blockage in the optical path may be clipped at the saturation voltage. In other words, a received LED signal that generates a first voltage output (e.g., 16V) may be considered the same as another received LED signal that generates a second, lower (or higher) voltage output (e.g., 12V), even if those LED signals indicate different path health. In this situation, it may be impossible to determine the health of the entire optical path with complete accuracy, because even if the optical path appears to be block-free at a particular current level applied to the LED, there may still be some blockage not otherwise indicated by the photoelectric sensor's output voltage level.

[0028] Accordingly, certain embodiments provide improved detection techniques for identifying one or more characteristics of an optical path in photoelectric sensor applications. For example, certain embodiments provide one or more techniques, implemented in transmitter and / or receiver circuit configurations described herein, for utilizing a changing current and / or gain, as described in detail herein.

[0029] Figure 1 shows a block diagram of an exemplary system 100 configured to specify the characteristics of an optical path according to a particular embodiment. Optionally, system 100 may be implemented in one of ports RF1, RF2, RF3, RF4, and / or RF5 of the schematic diagram 200 of the pneumatic module in Figure 2. Referring again to Figure 1, system 100 includes a transmitter circuit configuration 102, an optical path 104, a receiver circuit configuration 106, an LED 108 configured to propagate light 110, a photodetector element 112 (e.g., a photodiode, phototransistor, photoresistor, etc.), and a controller 114. The transmitter circuit configuration 102 may be configured to supply current to the LED 108 to propagate the beam of light 110 through the optical path 104 as shown in the figure, and the receiver circuit configuration 106 to receive it and convert the received light 110 into a voltage output. The controller 114 may be configured to control the voltage and / or current inputs / outputs for each of the transmitter circuit configuration 102 and / or receiver circuit configuration 106. Furthermore, the controller 114 may be configured to sample the voltage output generated by the receiver circuit configuration 106. In certain embodiments, the optical path 104 corresponds to a path through one of the ports RF1, RF2, RF3, RF4, and / or RF5 in schematic diagram 200 of the pneumatic module in Figure 2. In particular, ports RF1, RF2, RF3, RF4, and / or RF5 correspond to cross-sections of fluid paths within the surgical console.

[0030] As described above, various configurations and / or techniques may be implemented in the transmitter circuit configuration 102 and / or receiver circuit configuration 106 to improve port detection. For example, the transmitter circuit configuration 102 may be configured to generate an increasing current input to the LED 108 (e.g., via the circuit described herein or any suitable current amplification circuit), thereby increasing the light 110 output from the LED 108. When the light 110 output from the LED 108 changes (e.g., increases), the voltage output in the receiver circuit may change (increase) to match the intensity of the light 110 through the optical path 104.

[0031] In certain embodiments, the current input to the LED 108 may be increased during a period beginning from a first point in time, during which the receiver circuit configuration 106 can receive light 110 via the photodetector element 112 and convert the received light 110 into a voltage output. In addition, the controller 114 may be configured to identify the point in time during which the voltage output exceeds a threshold. For example, the threshold voltage may be the saturation voltage of the amplifier included in the receiver circuit configuration 106 or a voltage level slightly lower than the saturation voltage of the amplifier. Based on the time difference between the point in time when the voltage output of the photodetector element 112 exceeds the threshold and the start of the current increase, the characteristics of the optical path 104 (e.g., shielding amount or overall health / collapse) can be identified. For example, the gain (or gradient) may be associated with the current increase, and similarly, the gain (or gradient) may be associated with the voltage output accordingly. The larger the gain or gradient, the shorter the time difference between the point in time when the voltage output of the photodetector element 112 exceeds the threshold and the start of the current increase. Furthermore, as will be further described herein, the greater the gain or gradient, the higher the expected level of unclipped voltage output in the receiver circuit configuration 106 (higher than the amplifier's saturation voltage). Therefore, a short time difference may indicate a higher expected level of unclipped voltage output and, consequently, less shielding and / or obstruction of the optical path 104. Accordingly, the controller 114 may be configured to compare the time difference with one or more thresholds, and if the time difference is greater than a particular threshold, this may indicate a particular level of occlusion and / or obstruction of the optical path 104 associated with that particular threshold. Thus, the health of the optical path can be confirmed by using a changing current input to the LED and measuring the voltage output based on the LED's light output, without the ambiguity caused by exceeding the amplifier's saturation voltage included in the receiver circuit configuration 106.

[0032] As an example, Figures 3A to 3C show various timing diagrams associated with the voltage levels and / or various gains of the circuit input or LED output according to a particular embodiment. In particular, Figure 3A is a group of graphs 300A of exemplary timing diagrams 301, 302, and 303 associated with various components of a transmitter circuit configuration (e.g., transmitter circuit configuration 102 in Figure 1). For example, an ON pulse (e.g., the pulse width from the falling edge to the rising edge of timing diagram 301) can be applied periodically over a period of time (e.g., every 200 ms over 200 μs (microseconds)) to an LED (e.g., LED 108 in Figure 1). This ON pulse can be generated by the falling edge of timing diagram 301 (e.g., from 3V to 0V) and trigger the falling edges of timing diagrams 302 and 303 as shown in the figure. For example, timing diagram 301 may correspond to the input of the transmitter circuit configuration, while timing diagrams 302 and 303, respectively, indicate the limit on the duration for which current is applied to the LED by providing a timeout (e.g., 1 ms). As shown in the figure, when the voltage level in timing diagram 301 drops from 3.3V to 0V, the voltage level in timing diagram 302 also drops from 3.6V to 0.3V. In this case, the output state of the amplifier acting as a comparator, represented by timing diagram 303, may be based on a comparison between the voltage level shown in timing diagram 302 and the threshold voltage 304 (e.g., 3.3V). As shown in the figure, when the voltage level in timing diagram 302 is lower than the threshold voltage 304, the output state of the amplifier is logically low (e.g., 0.0V, meaning that Q41 shown in Figure 8A is OFF).

[0033] As shown in Figure 3B, i.e., Graph 300B of an exemplary increasing current input (the increasing current input described with respect to transmitter circuit configuration 102 in Figure 1), the falling edge of the timing Figure 303 indicating the ON pulse triggers a ramp-up interval (e.g., duration 150 μs) to a current (or voltage) level that provides a desired maximum or plateau current (e.g., for 50 μs) to the LED (e.g., LED 108 in Figure 1). In certain embodiments, a controller (e.g., controller 114 in Figure 1) may include an analog-to-digital converter (ADC) synchronized with the LED ON pulse, thereby allowing the controller's ADC to periodically sample the voltage output of the receiver circuit configuration (e.g., receiver circuit configuration 106) within the ON pulse duration (e.g., every 5 μs, resulting in 40 samples over the total duration of 200 μs).

[0034] Figure 3C shows an exemplary voltage output received by the photodetector, sampled over the ON pulse duration. As shown in the figure, graph 300C includes lines A, B, C, D, E, F, G, and H (A-H), where each of lines A-H corresponds to a different increase in the voltage output based on the current input in graph 300B of Figure 3B. Although eight lines are shown in Figure 3C, it should be understood that many other lines exist that can correspond to various current inputs. As shown in the figure, each of lines A-E exceeds the saturation voltage line (e.g., 12V) at various points, while lines F-H do not reach the saturation voltage line. Therefore, each intersection point of lines A-H can indicate the characteristics of the optical path (e.g., optical path 104 in Figure 1). For example, lines A-H can indicate the degree of occlusion, with A being the least occluded and H being the most occluded. For example, the intersection points of lines A to E generally indicate that there is no occlusion in the optical path according to a threshold (the threshold may differ depending on the embodiment), line A indicates the smallest amount of occlusion, the intersection points of lines F to H generally indicate that the optical path is occluded according to a threshold, and line H indicates the largest amount of occlusion.

[0035] As can be seen from Figure 3C, the intersection point, or "bend point," shifts (for example, to the left or right with respect to line C) due to variations in the gain within the detection path (e.g., based on the blockage level). For example, with a nominal gain represented by line C (e.g., unity gain) (e.g., its expected plate level would be 24.0V), the ramp-up reaches a saturation level of 12.0V in 75μs, which could be considered the nominal point of the ramp-plat inflection point. With respect to the nominal plate line C, as the overall detection path gain increases (less blockage within this path), the expected voltage output increases in amplitude (e.g., the slope / gain increases), and the ramp-plat inflection point may shift to the left, which is represented, for example, by line B (e.g., with a gain of 1.50 and / or 36.0V as the expected plate) and / or line A (e.g., with a gain of 2.00 and / or an expected plate of 48.0V). Conversely, if the overall gain of the detection path is reduced (for example, if the blockage in the path is greater), the expected and actual voltage outputs will be as shown by lines D~H, as the gain further decreases due to the increasing blockage in the optical path.

[0036] However, as already explained, the voltage output at or above the saturation voltage may not be sufficient to determine the overall health of the optical path, because a portion of the voltage output may be clipped (e.g., as shown by lines A-D). Therefore, the method performed by the controller 114 described above can help determine the time difference between when the increasing current input begins and when the voltage exceeds a threshold (e.g., saturation) voltage level. Such a time difference may show a slope, for example, corresponding to one of lines A-H. Furthermore, the health of the optical path can be determined based on whether the voltage output reaches the saturation voltage level too late (e.g., after 75 μs). In particular, if the time difference corresponds to any of lines D-H, the overall health of the optical path can be considered to be worsening and / or blocked. Conversely, a time difference corresponding to lines A-C may indicate that there is no blockage in the optical path and / or that its health can be improved. Furthermore, as the time difference begins to increase, it can be determined that the optical path is deteriorating, or not currently blocked. Therefore, corrective measures can be taken before the optical path becomes blocked to a more serious level.

[0037] Referring again to Figure 1, in a particular embodiment, the gain of the amplifier included in the receiver circuit configuration 106 can be changed during a period beginning from a first time point in time to change the voltage output of the photodetector element 112. That is, for a given current input, the gain of the amplifier can be changed to two or more different values, and the voltage output can be used to identify a second time point in time when the voltage output of the photodetector element 112 exceeds a threshold. Thus, instead of (or in addition to) changing the voltage output by changing the current input to the LED 108, the time point in time when the voltage output exceeds a threshold (e.g., the saturation voltage described in Figure 3C) can be identified by changing the cane of the amplifier (for example, by changing the resistance connected to the amplifier using a varistor, a switch that selectively connects one or more resistors, etc.).

[0038] Referring again to Figure 3C, each of the lines A to H can be defined by two points. In relation to Figure 3C, the two points are the time value on the x-axis and the voltage output on the y-axis. The time value may, as previously mentioned, indicate a specific current input level to the LED 108 and / or a specific gain applied to the amplifier connected to the photodetector element 112. Thus, each of the lines A to H can be defined by two points, namely 1) (first current input and / or amplifier gain, first voltage output) and 2) (second current input and / or amplifier gain, second voltage output). Furthermore, at a certain time value, and therefore current input and / or amplifier gain, the voltage output corresponds to one of the lines A to H, insofar as the voltage output is lower than the measurable saturation voltage.

[0039] Therefore, in certain embodiments, multiple thresholds (e.g., voltage thresholds) may be implemented to specify the characteristics of the optical path 104. For example, one voltage threshold may correspond to a saturation voltage, and a sufficiently high current input and / or amplifier gain may be applied. If the output voltage exceeds the threshold while a sufficiently high current input and / or amplifier gain is applied, this may indicate clipping (e.g., corresponding to any of lines A to E), which means that other current inputs and / or amplifier gains should be used, and the voltage output should be compared to the other thresholds to specify the characteristics of the optical path 104 (e.g., which of lines A to E the output correlates with). For example, the current input and / or amplifier gain may be set to a value correlated with 50 μs, as shown in Figure 3C, and the threshold may be set to the output voltage of line C at 50 μs, as shown in Figure 3C. Therefore, if the new output voltage exceeds the new threshold in this situation, the optical path 104 can be judged to be sufficiently healthy, because the output voltage corresponds to one of lines A to C and not to one of lines D to E (which corresponds to an output voltage lower than the new threshold).

[0040] Therefore, in certain cases, for a first current input applied to LED108, the output of the LED may be received and converted into a voltage output. It can be determined whether the voltage output is higher than (or equal to) a first threshold (e.g., a saturation threshold of 12V as shown in Figure 3C). If the voltage output is higher than the first threshold, a different current input (e.g., lower than the first current input) may be applied to LED108 and converted into a voltage output. Then, it can be determined whether the voltage output is higher than a second threshold (e.g., lower than the first threshold). The characteristics of the optical path 104 can be determined, as described above, based on whether the voltage output is higher than the second threshold for the second current input.

[0041] In a particular embodiment, a current input is applied to the LED 108, the output of the LED is received and converted based on an amplifier having a first gain. It can be determined whether the voltage output is higher than (or equal to) a first threshold (e.g., a saturation threshold of 12V as shown in Figure 3C), and if the voltage output is higher than the first threshold, a different gain greater than the first gain is applied to the amplifier to determine a second voltage output. It can then be determined whether the second voltage output is higher than a second threshold (e.g., lower than the first threshold). The characteristics of the optical path 104 can be determined, as described above, based on whether the voltage output is higher than the second threshold with respect to the second gain.

[0042] Figure 4 is a flowchart illustrating an exemplary operation 400 for identifying the characteristics of an optical path (e.g., optical path 104 in Figure 1) corresponding to a fluid path in the apparatus, according to a particular aspect of the present disclosure. Operation 400 may be performed, for example, by a system (e.g., system 100 shown in Figure 1).

[0043] The operation is 405, which begins by increasing the current input to the light-emitting element (LEE) (e.g., LED108 in Figure 1) over a period starting from the first time point.

[0044] At 410, the system receives the LEE output via the optical path during that period by a photodiode (or other photodetector such as the photodetector element 112 in Figure 1).

[0045] At 415, the system converts the LEE output to a voltage output during that period.

[0046] At 420, the system identifies a second point in time during which the voltage output exceeded the threshold.

[0047] At point 425, the system determines the characteristics of the optical path between the LED and the photodiode based on the difference between the second time point and the first time point.

[0048] In a particular embodiment of operation 400, the characteristics of the optical path include the amount of occlusion within the optical path.

[0049] In a particular embodiment of operation 400, the threshold is the saturation voltage of an amplifier connected to the photodetector.

[0050] In a particular embodiment of operation 400, determining the characteristics of the optical path between the LEE and the photodetector based on the difference between a second time point and a first time point includes determining whether the difference is greater than a certain time value. In this case, operation 400 may further include providing an indication of optical path occlusion when the difference is greater than that time value.

[0051] In a particular embodiment of operation 400, the optical path is located within a pneumatic port (for example, one of ports RF1, RF2, RF3, RF4, or RF5 in Figure 2).

[0052] In a particular embodiment of operation 400, the voltage input to the LEE is amplified using a resistor-capacitor (RC) circuit having a time constant associated with the period.

[0053] Figure 5 is a flowchart illustrating an exemplary operation 500 for identifying the characteristics of an optical path (e.g., optical path 104 in Figure 1) corresponding to a fluid path in a medical device, according to a particular aspect of this disclosure. Operation 500 may be performed, for example, by a system (e.g., system 100 shown in Figure 1).

[0054] The operation begins with 505 emitting a light output from the LEE (e.g., LED108 in Figure 1) for a period of time starting at the first point in time.

[0055] At 510, the system receives the LEE output via the optical path during that period by a photodiode (or other photodetector such as the photodetector element 112 in Figure 1).

[0056] At 515, the system converts the LEE output to a voltage output during that period.

[0057] At 520, the system changes the voltage output by changing the gain of an amplifier coupled to the voltage output during that period.

[0058] At 525, the system identifies a second point in time during which the voltage output exceeds the threshold.

[0059] At 530, the system identifies the characteristics of the optical path between the LEE and the photodetector based on the difference between the second time point and the first time point.

[0060] In a particular embodiment of operation 500, the characteristics of the optical path include the amount of occlusion within the optical path.

[0061] In a particular embodiment of operation 500, changing the gain of the amplifier includes changing the resistor connected to the amplifier.

[0062] In a specific embodiment of operation 500, the threshold is the saturation voltage of the amplifier.

[0063] Figure 6 is a flowchart illustrating an exemplary operation 600 for identifying the characteristics of an optical path (e.g., optical path 104 in Figure 1) corresponding to a fluid path in a medical device, according to a particular aspect of this disclosure. Operation 600 may be performed, for example, by a system (e.g., system 100 shown in Figure 1).

[0064] The operation begins with the 605 applying a first current input to the LEE (for example, LED108 in Figure 1).

[0065] In 610, the system receives the output of the LEE via an optical path while a first current input is applied to the LEE, using a photodiode (or other photodetector such as the photodetector element 112 in Figure 1).

[0066] In the 615, the system converts the LEE output into a voltage output.

[0067] At 620, the system determines whether the voltage output is greater than the first threshold.

[0068] As shown in the diagram, operations 625-645 are performed when the voltage output is greater than the first threshold.

[0069] At 625, the system applies a second current input to LEE.

[0070] At 630, the system receives the output of the LEE via the optical path while a second current input is applied to the LEE by a photodetector.

[0071] In the 635, the system converts the LEE output to another voltage output.

[0072] At 640, the system determines whether its other voltage output is greater than the second threshold, the second current is less than the first current, and the second threshold is lower than the first threshold.

[0073] In step 645, the system identifies the characteristics of the optical path based on whether its other voltage output is greater than a second threshold.

[0074] In a particular embodiment of operation 600, the characteristic of the optical path is the amount of occlusion within the optical path.

[0075] In a particular embodiment of operation 600, the first voltage output is the saturation voltage of an amplifier connected to the photodetector element.

[0076] In certain embodiments, operation 600 further includes providing an indication of optical path occlusion when its other output voltage is lower than a second threshold.

[0077] In a particular embodiment of operation 600, the optical path is located within the pneumatic port.

[0078] Figure 7 is a flowchart illustrating an exemplary operation 700 for identifying the characteristics of an optical path (e.g., optical path 104 in Figure 1) corresponding to a fluid path in a medical device, according to a particular aspect of the present disclosure. Operation 700 may be performed, for example, by a system (e.g., system 100 in Figure 1).

[0079] The operation begins with the 705 applying a current input to the LEE (for example, LED108 in Figure 1).

[0080] In step 710, the system receives the output of the LEE via an optical path while a current input is applied to the LEE, using a photodiode (or other photodetector such as the photodetector element 112 in Figure 1).

[0081] In the 715, the system converts the LEE output to a voltage output while an amplifier coupled to the LEE is configured with a primary gain.

[0082] At 720, the system determines whether the voltage output is greater than the first threshold.

[0083] As shown in the diagram, operations 725-745 are performed when the voltage output is greater than the first threshold.

[0084] In the 725, the system applies a current input to the LEE while the amplifier connected to the LEE is configured with a second gain.

[0085] In the 730, the system receives the output of the LEE via the optical path while a current input is applied to the LEE and the amplifier is configured with a second gain, using a photodetector.

[0086] In the 735, the system converts the LEE output to another voltage output.

[0087] At 740, the system determines whether the other voltage output is greater than the second threshold, the second gain is lower than the first gain, and the second threshold is lower than the first threshold.

[0088] At 745, the system identifies the characteristics of the optical path based on whether its other voltage outputs are greater than a second threshold.

[0089] In a particular embodiment of operation 700, the characteristic of the optical path is the amount of occlusion within the optical path.

[0090] In a particular embodiment of operation 700, changing the gain of the amplifier includes changing the resistor connected to the amplifier.

[0091] In a particular embodiment of operation 700, the first threshold is the saturation voltage of the amplifier.

[0092] In certain embodiments, operation 700 further includes providing an indication of optical path occlusion when its other output voltage is lower than a second threshold.

[0093] In a particular embodiment of operation 700, the optical path is located within the pneumatic port.

[0094] Exemplary circuit system and implementation Figures 8A-8B together show exemplary schematic diagrams of a circuit 800 that detects any blockage in the optical path (e.g., optical path 802 in Figure 8B) according to a particular embodiment. Although only circuit 800 is shown as an exemplary circuit on which the methods and techniques described herein can be performed, it should be understood that the techniques described herein are not limited to being completed only with circuit 800. In other words, circuit 800 may generally be configured to increase the current input to the LED, and other circuit configurations (e.g., multiplexer configurations) that generate an increasing (lamping) voltage output may also be appropriate.

[0095] Circuit 800 includes an emitter (or transmitter) side circuit configuration 804 (e.g., corresponding to transmitter circuit configuration 102 in Figure 1) and a detector (or receiver) side circuit configuration 806 (e.g., corresponding to receiver circuit configuration 106 in Figure 1), as shown in Figures 8A and 8B, respectively. Consumable parts are represented by the "Port 1 connector" between the LED emitter DS46 and the detector DS47.

[0096] Referring to circuit 800 in Figure 8A, before the falling edge of P1_TX_N (e.g., corresponding to timing figure 301 in Figure 3A) is reached, the current in resistor R116 charges capacitor C110 to a supply voltage V12X of 12.0V. However, Schottky diode CR32 prevents such charging by inducing the current from R116 to the supply voltage V3P3 (e.g., 3.3V). It is assumed that the supply voltage V3P3 can absorb the current, and if it cannot, a dummy load can be applied. Therefore, the non-inverting input 3 of amplifier U21A (e.g., operational amplifier) ​​is approximately 3.6V (e.g., supply voltage 3.3V plus the forward voltage of diode CR32 (V f ) = 0.3V, and output 1 of amplifier U21A is 12.0V, which is HI. It should be noted that amplifier U21A is used as a comparator in this implementation.

[0097] When the output of amplifier U21A is HI, transistor Q41 is held in the ON state, and all current that would normally pass through resistor R117 to charge capacitor C112 is shunted to GND. Transistor Q41 has a relatively low ON state resistance (for example, R DS,ON This effectively zeros the non-inverting input 5 of amplifier U22B, thereby keeping emitter LED DS46 in the OFF state. Resistor R118 is not present for any waveform generation, but it certainly prevents transistor Q41 from drawing excessive current when it is time for capacitor C112 to discharge.

[0098] At the start of the P1_TX_N pulse (for example, the falling edge of graph 301 shown in Figure 3A), the transition of P1_TX_N from 3.3V to 0.0V causes a transition from 3.6V to 0.3V at the non-inverting input 3 of amplifier U21A (for example, due to the 0.3V of diode CR32 as described above). When the voltage level of the non-inverting input 3 of amplifier U21A falls below the 3.3V voltage level of the inverting input 2 of amplifier U21A, the comparator behavior of amplifier U21A causes output 1 to swing to GND (for example, LOW). This then turns transistor Q41 OFF, and resistor R117 can charge capacitor C112.

[0099] Capacitor C110 is charged exponentially by resistor R116, but the time it takes for capacitor C110 to reach the 3.3V level required for output 1 to time out amplifier 21A can be estimated by assuming a relatively constant (or nearly linear) charging current.

number

[0100] moreover, Since CΔV = IΔT, the following holds.

number

[0101] Therefore, the time required for the output 1 of amplifier U21A to swing HI and turn on transistor Q41 is approximately 1.4 ms, which in turn turns off LED emitter DS46. In some cases, this time can be reduced to 1.0 ms or less by decreasing the resistance of resistor R116.

[0102] When transistor Q41 switches to the OFF state, charging of capacitor C112 via resistor R117 may begin. As in the case described above, capacitor C112 charges exponentially (e.g., time constant 43.2kΩ * 0.01μF = 432μs), (μF = microfarad, kΩ = kilohm), and capacitor C112 is then charged until Schottky diode CR33 is forward-biased. In a particular embodiment, the forward bias of Schottky diode CR33 nominally occurs when the non-inverting input 5 of amplifier U22B reaches a voltage of 3.6V. For example, the non-inverting input 5 of amplifier U22B may reach 3.6V after approximately 154μs, given the time constant, 3.6V level, and supply voltage V12X of 12V. Therefore, this could be the time it takes for the LED emitter current to ramp up to a plateau level, and in some cases, relatively high precision in the values ​​for C112 and R117 may be beneficial in achieving a charging time of approximately 154 μs. In some cases, when capacitor C112 is ceramic, it may contain a Class 1 (e.g., C0G) dielectric and have a relatively high voltage rating (e.g., 100V or higher).

[0103] 3.6V is the V3P3 supply voltage of 3.3V for the Schottky diode CR33. f By adding this to 0.3V, it can be identified as the forward bias voltage of the Schottky diode CR33. In this case, the V3P3 supply is

number

[0104] The operation of amplifier U22B causes the voltage at the non-inverting input 5 to be reflected by the plate resistor R119 (for example, to set the current). Transistor Q42 is controlled at its gate by the output 7 of amplifier U22B, which adjusts the voltage at R119 and therefore the current through the LED emitter DS46. Thus, amplifier U22B is connected in a voltage follower configuration, in which case the voltage gain may be little to no, and therefore relatively stable (for example, stable at unity gain).

[0105] As shown in the diagram, resistor R119 has a value of 5 ohms and can therefore be configured to withstand / break down a peak pulse current of 1.0 ampere for the LED emitter. Depending on the circumstances, resistor R119 can be increased to 10 ohms (e.g., for an LED emitter peak pulse current of 500 mA), or even to 50 ohms (e.g., for an emitter peak pulse current of 100 mA). For example, resistor R119 can be increased if the rest of the sensor signal path has adequate gain. In certain embodiments, the duty cycle is so small that even if the power output during the on-period of the duty cycle is 5-10 watts, the resulting output from transistor Q42 and / or resistor R119 may be only 50 mW (milliwatts) (average power), which would be considerably lower than each of their respective ratings.

[0106] Regarding the detector (or receiver) side circuit configuration 806 in Figure 8B, the photodiode DS47 may be configured to receive the output of the LED emitter DS46 and convert the light emitted from the LED emitter DS46 into a voltage. This voltage may be received by an amplifier U22B (e.g., a mutual impedance amplifier), with the offset reference of resistor R120 and capacitor C114 being filtered locally. The resistor-capacitor (RC) setup may keep the amplifier U22B off the ground rail for a generally faster response and improved fidelity at the tip. The detector side circuit configuration 806 further includes a capacitor C116 to maintain bandwidth (e.g., to stabilize and / or compensate for the input signal). The capacitance of capacitor C116 may be increased if necessary. In certain embodiments, the voltage output from the photodiode DS47 can be changed by adjusting the gain of the amplifier U22B by changing the resistance of resistor R121. As shown in the figure, the scaling circuit configuration 808 may also provide a 12V-3V scale, which can be coupled to the P1_RX node.

[0107] Figure 9 shows an embodiment of a surgical console 901 for a pneumatic ophthalmic surgical machine, in which one or more of the techniques described herein may be implemented. For example, the circuit 800 of Figures 8A and 8B may be implemented within this surgical console 901 to perform port detection. The surgical console 901 may be configured to drive one or more tools 903 (e.g., pneumatic tools). The tools 903 may include, for example, scissors, vitrectomy devices, forceps, and injection or extraction modules. Other tools 903 may also be used. During surgery, the pneumatic ophthalmic surgical machine of Figure 9 may operate to assist the surgeon in performing various ocular surgical procedures, such as vitrectomy. Compressed gas, such as nitrogen, may provide power to drive the tools 903 through the surgical console 901. The surgical console 901 may include a display 909 for displaying information to the user (the display may also incorporate a touchscreen for receiving user input). The surgical console 901 may also include a port 907 for connecting a fluid module 905 (e.g., to support perfusion / suction functions) to a tool 903 (e.g., via a wire or tube for pneumatics attached to the tool 903). The surgical console 901 may be configured to identify the characteristics of the optical path of port 907 (e.g., of the fluid module 905) according to the embodiments described herein. That is, a circuit configuration (e.g., system 100 in Figure 1 and / or circuit 800 in Figures 8A and 8B) may be included in the surgical console 901 to detect the integrity of the optical path in port 907 during surgery and to confirm that there are no blockages in the path.

[0108] Figures 10A and 10B show schematic diagrams of a pneumatic system for a pneumatic vitrectomy machine. As can be seen in Figures 10A and 10B, the pneumatic system may include a pneumatic valve 1017 for connecting a pressure source 1009 (e.g., a regulated pressure source such as a gas cylinder or a wall-mounted outlet type gas supply source) to output port A 1013 ("port A") and output port B 1015 ("port B"). Ports A and B may be connected to a tool 903 through port 907. Furthermore, the system (e.g., system 100 in Figure 1) may be installed in ports A and / or B to perform port detection (as described above) with respect to port 907. In some embodiments, the pneumatic valve 1017 may be controlled by a controller 1005 (e.g., corresponding to controller 114 in Figure 1). In some embodiments, the pressure of the pressure source 1009 may also be controlled by the controller 1005 or by a separate controller (e.g., located inside the surgical console 901). The controller 1005 may adjust the pressure (e.g., to balance between low pressure for reducing gas consumption and high pressure for increasing cutting speed, and / or to increase the dynamic range of available cutting speeds). In certain embodiments, the controller 1005 may include and / or be configured to specify the characteristics of the optical path as described herein.

[0109] In some embodiments, the components of the pneumatic system may be incorporated into one or more manifolds (e.g., machined from a metal such as aluminum) or manifold plates. The manifolds may be airtight, may include various fittings and joints, and may be able to withstand relatively high gas pressures. The manifolds may be manufactured as individual parts or as a single part. In various embodiments, the components of the pneumatic system (e.g., within the manifolds) may be incorporated inside the surgical console 901.

[0110] The pneumatic valve 1017 may include a solenoid that operates to move the pneumatic valve 1017 to one of two positions (see, for example, Figures 10A and 10B) as instructed by a control signal from the controller 1005. In the first position, the pneumatic valve 1017 may allow pressurized gas to pass through the valve 1017 to the output port B 1015 to provide pneumatic power to the probe cutter 1025, while simultaneously allowing the pressurized gas to pass through the exhaust port 1027. In the second position, the pneumatic valve 1017 may supply pressurized gas to port A and allow the pressurized gas to pass through the output port B 1015 to the exhaust port 1027. In this position, the pressurized gas may pass through port A to supply pneumatic power to the tool 703 (e.g., the probe cutter 1025). Therefore, when the pneumatic valve 1017 is in the first position, the first chamber 1029 of the dual chamber 1023 may be filled, while the second chamber 1031 may be discharged. When the pneumatic valve 1017 is in the second position, the second chamber 1031 may be filled, while the first chamber 1029 may be discharged. In certain embodiments, the probe cutter 1025 may be moved by a diaphragm 1021, which in turn vibrates as pressurized gas is alternately directed to ports A and B and to each chamber of the dual chamber 1023. As shown in Figures 10A and 10B, the probe cutter 1025 may be attached to ports A and B via a tube 1019. However, in other embodiments, separate tubes may be used for each port. Note that in the pneumatic system shown in Figure 10A, only a single pressure sensor 1011 is used, while in the pneumatic system shown in Figure 10B, two pressure sensors 1012a and 1012b are used. Similarly, although shut-off valves are not shown in Figures 10A and 10B, in certain embodiments, shut-off valves may be coupled to the pneumatic valve 1017 to supply pressurized gas to the pneumatic valve 1017 or to stop the flow of pressurized gas to the pneumatic valve 1017.

[0111] As shown in Figure 11, the probe cutter 1025 may act as a cutting device. The probe cutter 1025 can reciprocate inside the outer tube 1103, which has a cutter port 1101. As the probe cutter 1025 moves back and forth, the probe cutter 1025 may alternately open and close the cutter port 1101 with its pointed tip. Each cycle of the probe cutter 1025 through the outer tube 1103 may cut a material such as a vitreous body within the cutter port 1101 when the probe cutter 1025 is closed.

[0112] Embodiment 1: A method for identifying the characteristics of an optical path corresponding to a fluid path of a medical device, comprising: increasing the current input to a light-emitting element (LEE) over a period starting from a first time point; receiving the output of the LEE via the optical path during that period using a photodetector; converting the output of the LEE into a voltage output during that period; identifying a second time point during that period when the voltage output exceeds a threshold; and identifying the characteristics of the optical path between the LEE and the photodetector based on the difference between the second time point and the first time point.

[0113] Embodiment 2: In the method of Embodiment 1, the characteristics of the optical path include at least one of the amount of occlusion or the amount of collapse within the optical path.

[0114] Embodiment 3: In the method of Embodiment 1 or 2, the threshold includes the saturation voltage of an amplifier connected to the photodetector element.

[0115] Embodiment 4: In any one of Embodiments 1 to 3, determining the characteristics of the optical path between the LEE and the photodetector based on the difference between a second time point and a first time point includes determining whether that difference is greater than a certain time value.

[0116] Embodiment 5: The method of Embodiment 4 further includes providing at least one indication of optical path occlusion or collapse when the difference is greater than its time value.

[0117] Embodiment 6: In any one of Embodiments 1 to 5, the optical path is located within the pneumatic port.

[0118] Embodiment 7: In any one of Embodiments 1 to 6, the current input to the LEE is increased by using a resistor-capacitor (RC) circuit having a time constant associated with the period.

[0119] Embodiment 8: A method for identifying the characteristics of an optical path corresponding to a fluid path of a medical device, comprising: emitting an optical output from a LEE over a period starting from a first time point; receiving the output of the LEE via the optical path during that period using a photodetector; converting the output of the LEE into a voltage output during that period; changing the voltage output by changing the gain of an amplifier connected to the voltage output during that period; identifying a second time point during that period in which the voltage output exceeds a threshold; and identifying the characteristics of the optical path between the LEE and the photodetector based on the difference between the second time point and the first time point.

[0120] Embodiment 9: In the method of Embodiment 8, the characteristics of the optical path include at least one of the amount of occlusion or the amount of collapse within the optical path.

[0121] Embodiment 10: In the method of Embodiment 8 or 9, changing the gain of the amplifier includes changing the resistor connected to the amplifier.

[0122] Embodiment 11: In any one of Embodiments 8 to 10, the threshold voltage includes the saturation voltage of the amplifier.

[0123] Embodiment 12: A method for identifying the characteristics of an optical path corresponding to a fluid path of a medical device, comprising: applying a first current input to a LEE; receiving the output of the LEE via the optical path using a photodetector while the first current input is applied to the LEE; converting the LEE output to a voltage output; determining whether the voltage output is greater than a first threshold; applying a second current input to the LEE if the voltage output is greater than the first threshold; receiving the output of the LEE via the optical path using a photodetector while the second current input is applied to the LEE; converting the LEE output to another voltage output; determining whether the other voltage output is greater than a second threshold, wherein the second current is lower than the first current and the second threshold is lower than the first threshold; and identifying the characteristics of the optical path based on whether the other voltage output is greater than the second threshold.

[0124] Embodiment 13: In the method of Embodiment 12, the characteristics of the optical path include at least one of the amount of occlusion or collapse of the optical path.

[0125] Embodiment 14: In the method of Embodiment 12 or 13, the first voltage output includes the saturation voltage of an amplifier connected to the photodetector element.

[0126] Embodiment 15: The method of any one of Embodiments 12 to 14 further comprises providing at least one indication of optical path occlusion or collapse when the other output voltage is lower than a second threshold.

[0127] Embodiment 16: In any one of Embodiments 12 to 15, the optical path is located within the pneumatic port.

[0128] Embodiment 17: A method for identifying the characteristics of an optical path corresponding to a fluid path of a medical device, comprising: applying a current input to a LEE; receiving the output of the LEE via the optical path using a photodetector while a first current input is applied to the LEE; converting the output of the LEE into a voltage output; determining whether the voltage output is greater than a first threshold; applying a second current input to the LEE if the voltage output is greater than the first threshold; receiving the output of the LEE via the optical path using a photodetector while the second current input is applied to the LEE; converting the output of the LEE into another voltage output; determining whether the other voltage output is greater than a second threshold, wherein the second current is lower than the first current and the second threshold is lower than the first threshold; and identifying the characteristics of the optical path based on whether the other voltage output is greater than a second threshold.

[0129] Embodiment 18: In the method of Embodiment 17, the characteristics of the optical path include at least one of the amount of occlusion or collapse of the optical path.

[0130] Embodiment 19: In the method of Embodiment 17 or 18, changing the gain of the amplifier includes changing the resistor connected to the amplifier.

[0131] Embodiment 20: In any one of Embodiments 17 to 19, the first threshold is the saturation voltage of the amplifier.

[0132] Embodiment 21: The method of any one of Embodiments 17 to 20 further comprises providing at least one indication of optical path occlusion or collapse when the other output voltage is lower than a second threshold.

[0133] Embodiment 22: In any one of Embodiments 17 to 21, the optical path is located within the pneumatic port.

[0134] Embodiment 23: An apparatus for determining the characteristics of an optical path corresponding to a fluid path of a medical device, comprising means for performing one or more of the methods of Embodiments 1 to 22.

[0135] Embodiment 24: An apparatus for determining the characteristics of an optical path corresponding to a fluid path of a medical device, comprising a transmitter circuit configuration connected to a photodetector and a receiver circuit configuration connected to a photodetector, configured to perform one or more of the methods of Embodiments 1 to 22.

[0136] The foregoing description is provided to enable those skilled in the art to practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments. Therefore, the claims are not intended to be limited to the embodiments shown herein, but rather the entire scope consistent with the language of the claims should be recognized.

Claims

1. A method for identifying the characteristics of an optical path corresponding to a fluid path in a medical device, Over a period starting from the first point in time, the current input to the light-emitting element (LEE) is increased, The photodetector receives the output of the LEE via the optical path during the period, During the aforementioned period, the output of the LEE is converted to a voltage output, Identifying a second point in time during the aforementioned period when the voltage output exceeds a threshold, A method comprising identifying a characteristic, which includes at least one of the amount of obstruction or collapse of the optical path between the LEE and the photodetector, based on the time difference between the second time point and the first time point.

2. The method according to claim 1, wherein the threshold voltage includes the saturation voltage of an amplifier connected to the photodetector.

3. The method according to claim 1, wherein determining the characteristics of the optical path between the LEE and the photodetector based on the time difference between the second time point and the first time point includes determining whether the time difference is greater than a certain time value.

4. The method according to claim 3, further comprising providing at least one indication of occlusion or collapse of the optical path when the time difference is greater than the time value.

5. The method according to claim 1, wherein the optical path is located within the pneumatic port.

6. The method according to claim 1, wherein the current input to the LEE is increased using a resistor-capacitor (RC) circuit having a time constant associated with the period.

7. A method for identifying the characteristics of an optical path corresponding to a fluid path in a medical device, The light-emitting element (LEE) emits light output over a period starting from the first point in time, The photodetector receives the output of the LEE during the aforementioned period via the optical path, During the aforementioned period, the output of the LEE is converted to a voltage output, During the aforementioned period, the gain of the amplifier connected to the voltage output is changed to change the voltage output, Identifying a second point in time during the aforementioned period when the voltage output exceeds a threshold, A method comprising identifying a characteristic, which includes at least one of the amount of obstruction or collapse of the optical path between the LEE and the photodetector, based on the time difference between the second time point and the first time point.

8. The method according to claim 7, wherein changing the gain of the amplifier includes changing the resistor connected to the amplifier.

9. The method according to claim 7, wherein the threshold voltage includes the saturation voltage of the amplifier.

10. A method for identifying the characteristics of an optical path corresponding to a fluid path in a medical device, Applying a first current input to the light-emitting element (LEE), The photodetector receives the output of the LEE via the optical path while the first current input is applied to the LEE, Converting the output of the LEE to a voltage output, To determine whether the voltage output is greater than the first threshold, When the voltage output is greater than the first threshold, Applying a second current input to the aforementioned LEE, The photodetector receives the output of the LEE via the optical path while the second current input is applied to the LEE, Converting the output of the aforementioned LEE to another voltage output, The process involves determining whether the aforementioned other voltage output is greater than a second threshold, The second current is lower than the first current. The second threshold is lower than the first threshold. To identify, A characteristic including at least one of the amount of occlusion or collapse of the optical path is identified based on whether the other voltage output is greater than the second threshold, A method that includes this.

11. The method according to claim 10, wherein the voltage output includes the saturation voltage of an amplifier connected to the photodetector element.

12. The method according to claim 10, further comprising providing at least one indication of occlusion or collapse of the optical path when the other output voltage is lower than the second threshold.

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