Light engine calibration system and method

Abstract

Embodiments of the present disclosure generally relate to systems and methods for calibrating Light Emitting Diode (LED) light engines. The systems and methods described herein include characterizing the performance of Red-Green-Blue (RGB) LED light engines to enable display of calibrated dimensionless output values ​​that accurately reflect the perceived brightness of the illumination generated by the light engine for a particular output color.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 223,692, filed Jul. 20, 2021, entitled “LIGHT ENGINE CALIBRATION SYSTEMS AND METHODS” with inventors Jing Xu, Jason L. Lee, Hari Krishna Kapparapu, and Dean Richardson, the entire contents of which are incorporated herein by reference as if fully and completely set forth herein.

[0002] This disclosure relates to systems and methods for calibrating a light - emitting diode (LED) light engine, and more particularly, to systems and methods for calibrating a red - green - blue (RGB) LED light engine that aids in the use of a dimensionless output setting value that reflects the observed brightness of illumination.

Background Art

[0003] In ophthalmic microsurgery, precise cutting and / or removal of various eye tissues is frequently required. In such surgeries, appropriate illumination inside the patient's eye is important, and an illumination probe of an ophthalmic lighting system is commonly used to illuminate the surgical field. For example, a user, such as a surgeon or other medical professional, may insert an illumination probe into the patient's eye for illuminating the interior of the eye for surgery. Generally, the probe is connected to an optical port of the ophthalmic lighting system via an optical fiber cable. The ophthalmic lighting system may be housed in a surgical console and includes a light engine (i.e., an illumination light source). The lighting system may also include other optical elements, such as a collimating optical system and a focusing optical system, that assist in transmitting the light beam generated by the light engine into the optical fiber within the optical fiber cable and the probe.

[0004] A light engine is generally a red-green-blue (RGB) light-emitting diode (LED) light engine that can produce a range of output colors and brightness levels resulting from the mixing of light generated from three LED colors when operated with various drive currents. However, since the output of each individual LED color is generally a nonlinear function of the input current, the resulting composite output also generally changes nonlinearly with respect to the input. Consequently, for example, a surgeon's adjustment of an LED light engine to a desired brightness setting may not linearly increase or decrease the observed illumination brightness, potentially leading to decreased surgical efficiency and / or a bitter user experience for the surgeon.

[0005] Therefore, there is a need for a calibration system and method for LED lighting devices that helps to create a dimensionless output setpoint that accurately reflects the observed brightness of the LED lighting device. [Overview of the Initiative] [Means for solving the problem]

[0006] This disclosure relates to a system and method for calibrating a light-emitting diode (LED) light engine, and more particularly to a system and method for calibrating an LED light engine that assists in the use of a dimensionless output setpoint that reflects the perceived brightness of the illumination.

[0007] In a particular embodiment, a method is provided for generating calibrated illumination light using a light engine of a lighting system, the method comprising: acquiring a first set of data relating to the light engine, the first set of data including measured output luminous flux data and color sensor luminance measurements of the light engine, wherein the measured output luminous flux data and color sensor luminance measurements correspond to drive intensity data of a light engine input parameter; determining a first mapping between the measured output luminous flux data and the drive intensity data; determining a second mapping between the measured output luminous flux data and color sensor luminance measurements; determining a third mapping between the drive intensity data and color sensor luminance measurements based on the first and second mappings; determining a fourth mapping between a plurality of dimensionless output setpoints of the lighting system and the drive intensity data based on the third mapping; receiving one of a plurality of dimensionless output setpoints from a user input; using the fourth mapping, matching one of the plurality of dimensionless output setpoints to a corresponding drive intensity of a light engine input parameter; and using the light engine to generate illumination light having a desired output luminous flux.

[0008] To allow for a more detailed understanding of the above-mentioned features of this disclosure, a more specific description of this disclosure, which has been briefly summarized above, can be obtained by referring to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings are only illustrative embodiments and should not be considered to limit the scope of this disclosure, as other equally effective embodiments may be recognized. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an exemplary surgical console equipped with an ophthalmic surgery lighting system according to a particular embodiment of the present disclosure. [Figure 2] Figure 2 shows the lighting system of Figure 1 according to a specific embodiment of the present disclosure. [Figure 3]Figure 3 shows a portion of the illumination probe of the illumination system of Figure 1 during ophthalmic surgery, according to a particular embodiment of the present disclosure. [Figure 4] Figure 4 shows a block diagram of selected components of the light engine controller of the lighting system of Figure 1, according to a particular embodiment of the present disclosure. [Figure 5] Figure 5 shows an exemplary graphical user interface of the surgical system of Figure 1 according to a particular embodiment of the present disclosure. [Figure 6] Figure 6 shows a flowchart illustrating a method for calibrating the light engine of the lighting system of Figure 1 according to a specific embodiment of the present disclosure. [Figure 7A] Figure 7A shows an exemplary table of initial test data used in the method of Figure 6 according to a particular embodiment of this disclosure. [Figure 7B] Figure 7B shows an exemplary fitted polynomial curve determined by the method of Figure 6, according to a particular embodiment of the present disclosure. [Figure 7C] Figure 7C shows an exemplary experimental table and corresponding exemplary graph determined in the method of Figure 6 according to a particular embodiment of the present disclosure. [Figure 7D] Figure 7D shows an exemplary fitted polynomial curve determined by the method of Figure 6, according to a particular embodiment of the present disclosure. [Figure 7E] Figure 7E shows an exemplary experimental table determined in the method of Figure 6 according to a particular embodiment of the present disclosure. [Figure 7F] Figure 7F shows an exemplary fitted polynomial curve determined by the method of Figure 6, according to a particular embodiment of the present disclosure. [Figure 7G] Figure 7G shows an exemplary experimental table determined in the method of Figure 6 according to a particular embodiment of this disclosure. [Figure 7H] Figure 7H shows an exemplary experimental table determined in the method of Figure 6 according to a particular embodiment of this disclosure. [Figure 7I] Figure 7I shows an exemplary experimental table determined in the method of Figure 6 according to a particular embodiment of the present disclosure. [Figure 7J] FIG. 7J shows an exemplary fitting polynomial curve determined in the method of FIG. 6 according to a particular embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] For ease of understanding, the same reference numbers are used whenever possible to indicate the same elements common to multiple drawings. The elements and features of one embodiment are intended to be beneficially incorporated into other embodiments without further elaboration.

[0011] In the following description, details are set forth as examples for purposes of facilitating an understanding of the disclosed subject matter. It should be apparent to those skilled in the art, however, that the disclosed implementations are examples and do not cover all possible implementations. Accordingly, reference to the examples described is not intended to limit the scope of the present disclosure. It is understood that any variations and further modifications to the devices, instruments, methods described, as well as any further applications of the principles of the present disclosure, are fully contemplated by those of ordinary skill in the art to which the present disclosure pertains. In particular, it is fully contemplated that the features, components, and / or steps described with respect to one implementation may be combined with the features, components, and / or steps described with respect to other implementations of the present disclosure.

[0012] It should be noted that, as described herein, the distal end, distal segment, or distal portion of a component refers to the end, segment, or portion that is closer to the target tissue of the patient during use of that component. On the other hand, the proximal end, proximal segment, or proximal portion of a component refers to the end, segment, or portion that is farther away from the target tissue of the patient.

[0013] As used herein, the term "about" may refer to a variation of + / - 10% from a nominal value. It is understood that such variations may be included in any value provided herein.

[0014] The present disclosure relates to a system and method for calibrating a light emitting diode (LED) light engine, and more particularly, to a system and method for calibrating an LED light engine such that the perceived brightness and color of the generated output light correspond to desired user input settings.

[0015] As described above, in certain existing LED lighting systems, since the output resulting from the light engine is a non-linear function of the input, when adjusting the desired output settings of the light engine, the observed characteristics of the generated illumination light may not change intuitively and linearly. For example, an RGB LED lighting source can generate a variety of output colors and brightness levels within a certain range resulting from the mixing of light generated from three LEDs when operated at various drive currents. Since the output of each individual LED is generally a non-linear function of the input current, the resulting composite output also changes non-linearly with respect to the input. Thus, when a user of an existing lighting system (e.g., a surgeon) attempts to increase or decrease the brightness of the illumination light during surgery by adjusting the settings of the light engine, the resulting difference in the actual brightness of the illumination light may not correspond to the desired setting adjustment by the surgeon. As a result, the surgeon may need to repeatedly adjust the settings of the light engine to obtain the desired brightness, thereby reducing the efficiency of the surgery and also potentially degrading the user experience of the surgeon.

[0016] Accordingly, the methods and systems described herein can be used to calibrate a lighting engine such that the observed change in brightness of the generated illumination light corresponds linearly to an increase or decrease in the brightness setpoint due to user input. For example, in certain embodiments described herein, a surgical system (e.g., a surgical console) may include a display device that shows the desired illumination brightness setpoint of an RGB LED lighting system as a percentage of full scale (e.g., 0 to 100%). The user can adjust the brightness setpoint percentage via an appropriate toggle such as a knob, button, or touchscreen interface. The adjustment of the brightness setpoint percentage is transmitted to the light engine interface, where a control module converts the brightness setpoint percentage into an appropriate electrical input, resulting in an observed illumination brightness level corresponding to the adjusted brightness setpoint percentage.

[0017] Figure 1 shows an exemplary surgical system 100 equipped with a lighting system according to a particular aspect of the present disclosure. In a particular example, the surgical system 100 is a surgical system for ophthalmic surgery, including but not limited to a surgical system sold by Alcon, located in Fort Worth, Texas. The system 100 may be used for a variety of ophthalmic procedures, such as anterior segment procedures, posterior segment procedures, vitreoretinal procedures, vitrectomy procedures, cataract procedures, and / or other surgical procedures. The surgical system 100 comprises a console 104 and an accompanying display 106. The display 106 may, for example, display data relating to the operation of the system during surgery and / or the performance of the system, and this data may be arranged in a graphical user interface (GUI).

[0018] Generally, console 104 comprises one or more systems or subsystems that enable a surgeon to perform various surgeries, such as ophthalmic surgery. For example, console 104 may include an illumination system (reference numeral 200 in Figure 2) having a light source that generates illumination light that can be guided into a body cavity so that a surgeon can perform surgery within the body cavity. The light generated by the light source may be transmitted into the eye via an optical fiber located in an optical fiber cable 102, with the distal end terminated by an illumination probe 108. In some implementations, the light may pass through one or more optical elements, such as one or more lenses, mirrors, and / or attenuators, before or after entering the optical fiber. In some implementations, an access instrument commonly called a cannula (reference numeral 310 in Figure 3) may be used to pass the optical fiber and / or illumination probe 108 of the illumination system into the eye. The cannula may be used to form or make an incision through the wall of the body cavity (e.g., through the sclera of the eyeball). In some examples, the cannula may be inserted into an incision made by a user, such as a surgeon or other medical professional, using other surgical instruments. A cannula generally has a lumen into which a surgeon can insert one or more surgical instruments or probes to perform surgery within a cavity.

[0019] An exemplary surgical instrument, shown as handpiece 112, may be coupled to console 104 and form part of surgical system 100. Handpiece 112 represents any type of ophthalmic surgical probe, including, for example, a vitrectomy probe, an illumination probe, a suction probe, a lavage probe, a phacoemulsifier, a diathermia probe, or other types of devices. In the illustrated implementation, handpiece 112 is a vitrectomy probe used to remove the vitreous humor from the eye. Handpiece 112 may be coupled to one or more systems or subsystems contained within console 104. For example, handpiece 112 may be coupled to a vitrectomy system that controls the pump and / or vacuum used for vitrectomy removal. The vitrectomy system may also supply power to handpiece 112 and control its operation. In some implementations, handpiece 112 may be a vitrectomy cutter, such as a vibrating vitreous cutter.

[0020] Figure 2 shows the illumination system 200 of Figure 1 according to a particular aspect of the present disclosure. The illumination system 200 may include an illumination probe 108 (e.g., an intraocular illumination device or a chandelier intraocular illumination device) coupled to a console 104 via an optical fiber cable 102 having one or more optical fibers arranged inside. The proximal end 212 of the optical fiber cable 102 is coupled to the console 104 using a connector 206.

[0021] Console 104 provides a light source comprising a light engine 208 and a light-gathering element 210, as in the example of Figure 2. The light engine 208 communicates with a controller 218 and may comprise any suitable type of light source, such as one or more light-emitting diodes (LEDs). For example, in a particular embodiment, the light engine 208 comprises one or more sets of red-green-blue (RGB) LEDs. During operation, upon receiving a control signal from the controller 218, the light engine 208 converts the control signal into an electrical input, which is supplied to one or more drive circuits and / or electrical components for driving the light source (e.g., RGB LEDs). In a particular embodiment, the control signal and / or electrical input may include, for example, a pulse-width modulation (PWM) duty cycle, a drive current, or one or more other suitable types of control parameters appropriate to the circuit design and driving scheme of the lighting system 200. After converting the control signal and providing the appropriate electrical input to the light source, the light engine 208 emits a light beam, which is then focused and concentrated by the focusing element 210 into an opening at the proximal end of the connector 206, exposing the proximal ends of one or more optical fibers extending through the optical fiber cable 102. The illumination probe 108 is then operable to transmit the light beam received from the light source so that light is projected from its distal end 214 to illuminate an area 216, such as a portion of the inner eye during ophthalmic surgery.

[0022] For example, Figure 3 shows a cross-sectional view of an eye 300 in which a portion of an illumination probe 108 is positioned through the eye wall 304 via a cannula 310 to provide a light source inside the eyeball. The distal end 214 of the illumination probe 108 illuminates an internal region of the eye 300 with a light beam 308.

[0023] Figure 4 shows a block diagram of selected components of an implementation of a controller, such as a controller 218, which is related to or coupled to a lighting system, such as a lighting system 200, which is part of a surgical console such as console 104, as described above with reference to Figures 1 and 2.

[0024] As shown in Figure 4, the controller 218 includes a processor 402 that communicates with memory 410. The controller 218 is further coupled via bus 416 to communicate with the display interface 404 and communication interface 420 of console 104, as well as the lighting system 200. In certain embodiments, the controller 218 is configured to interface with the lighting system 200 and other components of console 104 via bus 416. In some implementations, the communication interface 420 may be configured to allow the controller 218 to connect via a network to an external computing system (e.g., computing system 460), either wired or wirelessly. The network may include one or more switching devices, routers, local area networks (e.g., Ethernet), wide area networks (e.g., the Internet), etc. The computing system 460 may be an on-premises computing system or may correspond to computing resources provided by a private or public cloud. The controller 218 may also be connected via display interface 404 to one or more displays, such as display 106.

[0025] Memory 410 may include persistent, volatile, fixed, removable, magnetic, and / or semiconductor media. Memory 410 may be configured to store one or more machine-readable commands, instructions, data, and / or similar. In some implementations, as shown in Figure 4, memory 410 may include one or more sets and / or sequences of instructions, such as an operating system 412 and a calibration application 414. Examples of operating system 412 include, but are not limited to, UNIX® or UNIX®-like operating systems, Windows® family operating systems, or other suitable operating systems.

[0026] The calibration application 414 may be configured to perform light engine calibration operations described herein, including but not limited to operations relating to calibrating the observed output luminous flux or brightness against a received setpoint. For example, the light engine calibration application 414 may configure the controller 218 to perform a series of operations, such as operation 600, which determines one or more functions that translate a desired lighting setting (e.g., desired brightness) provided by a user into a calibrated control signal for the light engine 208. Once determined, the functions may be stored in memory 410 so that they can be retrieved during operation of the lighting system 200. For example, during operation of the lighting system 200, a user may input a desired lighting setting via the user interface of the display 106. The processor 402 then uses the desired lighting setting as input to one or more determined functions, outputs a calibrated control signal, and transmits the calibrated control signal to the lighting system 200. Next, the drive circuit 406 of the light engine 208 converts the calibrated control signal into a corresponding electrical input, which is supplied to the light engine 208 to generate illumination light corresponding to the desired lighting setting.

[0027] Although the processor 402 and memory 410 are shown as components of the controller 218, it should be noted that the lighting system 200 may have its own dedicated processor and memory capable of performing the same or similar functions as the processor 402 and memory 410 described above. In other words, the lighting system 200 may have a dedicated processor and memory, and the dedicated memory may include a calibration application configured to perform the light engine calibration operations described herein. In such embodiments, once one or more light engine calibration functions are determined, the functions may then be stored in the memory 410 of the controller 218 for use during the operation of the lighting system 200.

[0028] In certain embodiments, the light engine calibration operation is performed on a separate computing system (e.g., computing system 460) that communicates with console 104 and / or lighting system 200. In such embodiments, computing system 460 comprises a dedicated processor and memory, the dedicated memory storing a calibration application that performs the light engine calibration operation (e.g., operation 600) described herein to derive one or more functions for translating desired lighting settings into calibrated control signals for the light engine 208. In certain embodiments, one or more functions may then be transmitted and stored in memory 410 or memory dedicated to lighting system 200.

[0029] Figure 5 shows an exemplary GUI 500 that may be displayed on, for example, the display 106 of a surgical system 100. The GUI 500 may display, for example, data related to the operation and / or performance of the system during surgery, and / or data related to the operation or performance of one or more surgical devices (e.g., handpiece 112). The GUI 500 may further display one or more graphical control elements such as windows, toolbars, menus, buttons, and icons, which allow the user (e.g., a surgeon) to adjust one or more modes, parameters, or settings during surgery and to navigate through the displayed data.

[0030] In the example shown in Figure 5, the GUI 500 includes a window 508 that displays information related to the operation of one or more lighting devices (e.g., lighting probes 108) of the lighting system 200. The displayed information may include lighting output parameters or settings of one or more lighting devices, such as color and luminous flux (e.g., brightness). For example, as shown in Figure 5, a single lighting device (e.g., labeled "lighting device 1") is identified and displayed along with its output settings. The displayed output settings include a color setting 512 (set to "cool white" in this example) that identifies the current color of the illumination light emitted by lighting device 1, and a luminous flux or brightness setting 514 that identifies its current luminous flux as a unitless value on a percentage scale of 0 to 100%. Thus, the displayed luminous flux setting 514 corresponds to the percentage of the maximum possible luminous flux of illumination light generated by the corresponding light engine of lighting device 1.

[0031] In certain embodiments, for example, the values ​​of the color setting 512 and the brightness setting 514 may be adjusted by the surgeon via one or more toggles 516 or other appropriate control elements in the window 508. For example, during surgery, the surgeon can control the performance of one or more illuminators of the lighting system 200 via the GUI 500 by pressing one or more toggles 516 to change the value of the displayed lighting output setting, for example. By changing the value of the displayed output setting, a signal is then sent to the controller 218, which can adjust the performance of the corresponding light engine 208 of the illuminator by modulating the electrical input parameter applied thereto, for example. However, as described above, if the light engine 208 is an RGB LED light engine, the resulting output of the light engine 208 is a nonlinear function of the input. Therefore, in certain existing systems, when adjusting the brightness setting (e.g., luminous flux setting 514) of the light engine 208, the resulting brightness of the illumination light may not correspond intuitively and linearly to the brightness setting adjustment. As a result, surgeons may need to repeatedly adjust the luminous flux setting 514 of the light engine 208 to obtain the desired brightness, which can reduce surgical efficiency and degrade the surgeon's user experience. The above description addresses this shortcoming by providing a method for calibrating the RGB LED light engine so that the observed brightness of the generated illumination corresponds linearly to an increase or decrease in the output setpoint due to user input. In certain embodiments, the method described below may be performed by a computer or controller (e.g., controller 218) of the surgical system 100 or the illumination system 200. For example, the method described below may be performed by a computer running spreadsheet or tabular data software (e.g., a laboratory personal computer or a cloud-based computing resource (e.g., a NumPy notebook)).

[0032] Figure 6 shows a flowchart of method 600 for calibrating an RGB LED light engine (e.g., light engine 208) of a lighting system according to a particular aspect of this disclosure. Figures 7A to 7J schematically illustrate the operation of method 600 according to a particular aspect of this disclosure. For this reason, Figures 6 and 7A to 7J are described together in this specification for clarity.

[0033] Calibration of the RGB LED light engine 208 involves analyzing the input and output data presented by the light engine 208, as well as a series of empirical fits and their scaling normalization. This series of empirical fits and their scaling normalization yields a set of constants that enable precise mapping of dimensionless output setting values ​​(e.g., in the range of 0-100%) to the corresponding RGB LED driving parameters for the desired color. As a result, a consistent and intuitive relationship is established between user adjustments to the output setting value and the perceived change in the brightness of the illumination light, customized for the individual light engine 208. Thus, calibration of the RGB LED light engine 208 makes it possible to reliably and reproducibly convert the desired output setting value selected by the user into the corresponding observed (e.g., output) illumination brightness level in real time, while maintaining the desired color balance.

[0034] Next, looking at Figure 6, in operation 602 of method 600, initial test data of the light engine 208 is obtained and used to calculate a first polynomial fit or function that models the relationship between the output luminous flux of the light engine 208 and the drive intensity of the primary electrical input parameters of the light engine 208 for a particular preset color. The test data of the light engine 208 may include any suitable set of test or inspection data that provides presented output characteristics, such as the colorimetric characteristics of the light engine 208 for one or more preset colors, over a range of one or more electrical input parameters. In a particular embodiment, the electrical input parameters include the drive current, the duty cycle of a pulse-width modulation (PWM) signal, and so on.

[0035] For example, in certain embodiments, test data for the light engine 208 are collected by applying an LED drive current to the light engine 208, adjusting the duty cycle length of its PWM signal, and measuring the output characteristics (e.g., output luminous flux) of the light engine 208 over a range of duty cycle times via one or more sensors. In such embodiments, instead of adjusting the applied drive current, it is possible to maintain a fixed current value during testing by adjusting the duty cycle of the PWM signal, for example, via a continuous knob adjustment, thereby providing predictability and localization for a single input point on the calculated input-output curve and avoiding certain problems associated with the nonlinearity of the input to the observed output of the LED light engine (e.g., light engine 208). In certain embodiments where the duty cycle time of the PWM signal is used as an electrical input parameter, the PWM signal is filtered and converted to an analog drive current before being applied to the light engine 208. In certain embodiments, output characteristics are collected for each of several different drive inputs (e.g., drive currents) over a range of duty cycle times.

[0036] Figure 7A shows an exemplary table 700 with test data specific to a particular light engine 208. As shown, table 700 includes data related to the chromaticity and luminance of the light engine 208 for several pre-defined colors organized according to the International Commission on Illumination (CIE) xy color space. For example, the CIE system characterizes a color by two color coordinates x and y shown in columns Sp2 and Sp3 of table 700, respectively, and a luminance parameter Y shown in column Sp4. Note that in some examples, the number in column Sp4 is not exactly CIE Y, but is highly non-linearly correlated with it. Thus, in table 700, each different pair of coordinates (across rows) in columns Sp2 and Sp3 corresponds to a particular pre-defined color, and the luminance parameter Y in column Sp4 corresponds to the drive value of the electrical input parameter applied to the light engine 208 to propagate light having the pre-defined color. For illustrative purposes, five exemplary x,y color coordinate pairs (0.3,0.3, 0.4,0.3, 0.345,0.38, 0.3,0.4, and 0.4,0.4) are shown in Table 700, each representing a different preset color desired by the user. To calibrate the light engine 208 for each of the five preset color coordinates, test data for the light engine 208 is collected for each preset color, and together the remaining operations of Method 600 are performed individually, simultaneously or sequentially. Thus, each row (e.g., line) of the test data in Table 700 is separate to the corresponding preset color coordinates in columns Sp2 and Sp3.

[0037] In certain embodiments, test data are collected and provided by the manufacturer of the light engine 208. In certain embodiments, test data are collected by the manufacturer or assembler of the surgical system or lighting system (e.g., system 100 or 200, respectively). Generally, test data (e.g., test data including measured raw output characteristics of the light engine 208 over a range of drive values ​​with respect to primary electrical input parameters) are collected using one or more color sensors that may be located inside the light engine 208 or lighting system 200. Although the example in Figure 7A shows data from two color sensors, only one sensor is sufficient for the method herein. Since each light engine has its own set of test data, in certain embodiments, test data is collected for each light engine (e.g., light engine 208) used in a surgical system (e.g., surgical system 100), and method 600 is performed separately.

[0038] As shown in Figure 7A, Table 700 contains in column Sp26 the measured output luminous flux values ​​of the light engine 208 measured by a calibrated radiometer in lumens, and in column Sp4 the corresponding drive intensity values ​​for a range of specific electrical input parameters. In this example, the PWM duty cycle is used as the electrical input parameter. As described above, in operation 602, the relationship between the drive intensity value in Sp4 and the measured output luminous flux value in Sp26 is determined and analyzed for a specific color, and a fitted polynomial curve (also referred to herein as the first function) is generated therefor. Graph 702 in Figure 7B shows an exemplary fitted curve for the relationship in the color coordinates (0.345, 0.38), with the drive intensity plotted along the X-axis and the measured output luminous flux plotted along the Y-axis. As shown, the exemplary fitted curve is characterized by the following polynomial function. Luminous flux (lm)=(-1.615884e -06 ) × (drive value) 2 + (1.446163e -02 ) × (drive value)

[0039] In operation 604, once a fitted polynomial curve is formed that models the relationship between the measured output luminous flux of the light engine 208 in lumens and the driving intensity of the primary electrical input parameter, the polynomial fit is used to estimate the output luminous flux of the light engine 208 at the maximum driving intensity value, i.e., the estimated maximum output luminous flux. Generally, the maximum driving intensity value is the maximum input parameter value achievable by the lighting system 200 in which the light engine 208 is installed (e.g., assembled together). For example, in embodiments where a PWM signal is used as the input parameter, the maximum driving intensity value is the maximum PWM duty cycle allowed by the lighting system 200. In such embodiments, the maximum duty cycle may be limited, for example, by the communication rate between the controller of the surgical system 100 or lighting system 102 (e.g., the light engine controller 218) and the light engine 208, or by the clock rate of the control signal. Thus, the estimated maximum output luminous flux for the purposes of this disclosure corresponds to the 100% output setpoint of the light engine 208 when converted to a dimensionless output setpoint. Therefore, if the user (e.g., a surgeon) selects a desired output luminous flux setting of 100%, the light engine 208 will produce an observed output that is substantially equal to the estimated output luminous flux determined in operation 604.

[0040] For illustrative purposes, an exemplary calculation of the estimated maximum output luminous flux is shown below. The following calculation utilizes the polynomial fit derived in Figure 7B for the color coordinates (0.345, 0.38), i.e., the first function, and further utilizes 3200, an exemplary maximum drive intensity value corresponding to the system's maximum PWM duty cycle. Note that for any surgical and / or lighting system, the maximum drive intensity value of the electrical input parameter may differ and depend on its processing and / or calculation specifications. 29.73(lm) = (-1.615884e -06 ) × (3200) 2 +(1.446163e -02 ) × (3200)

[0041] Using the polynomial fitting described above, the calculated maximum output luminous flux for the 3200 is 29.73 lumens. In this example, 29.73 lumens corresponds to 100% luminous flux at the specific color coordinates (0.345, 0.38).

[0042] In operation 606, the estimated maximum output luminous flux of the light engine 208 for color coordinates (0.345, 0.38) is now obtained, and the mapping of the full range of target outputs (e.g., target outputs in lumens) is determined (e.g., in percentages) at each desired output setpoint step. In other words, the multiple target output luminous flux values ​​of the light engine 208 are mapped to dimensionless output setpoints on a percentage scale from 0 to 100%. The target output luminous flux value for each output setpoint can be calculated using the following formula: Luminous flux (lm) = (Estimated maximum output luminous flux) × (Desired output setting value (%))

[0043] For illustrative purposes, a representative table 704 and corresponding graph 706 are shown in Figure 7C to illustrate the mapping of target output to output setpoint steps in operation 606, applicable to the light engine 208 in the examples of Figures 7A and 7B. In the example of Figure 7C, the estimated maximum output luminous flux is 29.73 lm. Therefore, a desired output setpoint of 5% corresponds to a target output luminous flux of 1.49 lm, a desired output setpoint of 10% corresponds to a target output luminous flux of 2.97 lm, a desired output setpoint of 15% corresponds to a target output luminous flux of 4.46 lm, and so on. As is clear from graph 706, the mapped values ​​form a linear relationship or function between the target output luminous flux and the output setpoint.

[0044] Once the target output luminous flux value is determined for each desired output setting of the light engine 208, the target output luminous flux value is converted back to a corresponding drive intensity value (e.g., PWM duty cycle time) that can be input to the light engine 208 to reproduce the target output luminous flux value. Generally, this conversion is completed in multiple operations, starting with operation 608.

[0045] In operation 608, a second polynomial fit (also referred to herein as the second function) is calculated to model the relationship between the measured output luminous flux value of the light engine 208 (e.g., found in column Sp26 of the initial table 700) and the corrected color sensor Y values ​​(e.g., corrected luminance measurements found in column Sp9, measured by the first color sensor, and column Sp14, measured by the second color sensor). Although table 700 shows luminance measurements from two separate sensors, as described above, operation 608 only requires one set of luminance measurements from a single color sensor. Therefore, two sets of measurements are redundant, and either the set of values ​​from the first color sensor or the set of values ​​from the second color sensor may be used.

[0046] The color sensor Y value, listed in either column Sp9 or Sp14, is a color sensor measurement proportional to the luminous flux of the light engine 208 when light is shone on the color sensor. The light illuminating the color sensor is only a small portion of the total luminous flux from the light engine 208 that is directed towards the sensor by an internal light beam splitter. Therefore, this small portion of the light is highly correlated with the output luminous flux of the light engine 208. Thus, the color sensor Y value provides a constant for all desired preset colors, and the relationship between the color sensor Y value and the measured output luminous flux of the light engine 208 can be used as a bridge to convert the output setpoint (i.e., the percentage in representative table 704) into the desired drive intensity that causes the light engine 208 to produce a target output luminous flux value previously mapped to this output setpoint. The relationship between the measured output luminous flux and the color sensor Y value in the examples in Figures 7A-7C is shown in graphs 708 and 710 in Figure 7D. In particular, Graph 708 shows the measured output luminous flux plotted along the X-axis and the corrected color sensor Y-value plotted along the Y-axis, while Graph 710 shows the same data with the axes reversed. As both graphs show, the measured luminous flux and the color sensor Y-value exhibit a linear relationship, and only a single polynomial fit or function is commonly calculated to model the relationship.

[0047] In operation 610, a further mapping is determined between the target output luminous flux and the tuned color sensor Y value for each desired output setpoint, using the modeled relationship between the luminous flux and the color sensor Y value measured for the light engine 208. To illustrate the mapping in operation 610, a representative table 712 is shown in Figure 7E. The representative table 712 includes the target output luminous flux values ​​for each desired output setpoint, as seen in Table 704, but also includes columns labeled "corr Ya" and "corr Yb" for the tuned color sensor Y values ​​mapped to (e.g., calculated with respect to) the previously determined output setpoints and target output luminous flux values. The tuned color sensor Y value for each output setpoint can be determined using the following equation, where "a" is the coefficient of the fitting parameter determined in operation 608. Adjusted color sensor Y = (a) × (luminous flux (lm))

[0048] In operation 612, the adjusted color sensor Y values ​​determined for each target output luminous flux value and desired output setpoint of the light engine 208 are mapped to drive intensity values ​​for the primary electrical input parameters found in column Sp4 of the initial data table 700. Thus, to model the direct relationship between the adjusted color sensor Y values ​​(e.g., the columns "corr Ya" and "corr Yb" in representative table 712) and the drive intensity, a third polynomial fit, i.e., a third function, is calculated, which generally generates two fitting parameters. An exemplary graph 714 is shown in Figure 7F, which shows the adjusted color sensor Y values ​​plotted along the X axis and the drive intensity values ​​plotted along the Y axis. In the representative graph 714, data from each of the two color sensors is shown, but as mentioned above, only data from a single color sensor may be used. The relationships illustrated in graph 714 are color-dependent and therefore must be calculated for each desired preset color of the light engine 208 during calibration.

[0049] In operation 614, the adjusted color sensor Y value, target output luminous flux value, and output setpoint (e.g., output setpoint in dimensionless (percentage) units) are further mapped to an adjusted drive intensity value. The adjusted drive intensity may be determined using the following equation, where "a" and "b" are coefficients of the fitting parameters determined in operation 612. Adjusted drive = (a) × (adjusted color sensor Y) 2 +(b) × (Adjusted color sensor Y)

[0050] Once the adjusted drive strength values ​​are determined, the percentage (%) of each adjusted drive strength value relative to the maximum drive strength (in the examples in Figures 7A to 7F, the maximum drive strength value is 3200) is calculated using the following formula. Adjusted drive % = (Adjusted drive) / (Maximum drive) × 100%

[0051] A typical table 716 with the adjusted drive intensity and drive intensity percentage of the light engine 208 entered, based on the examples in Figures 7A to 7F, is shown in Figure 7G. As shown, the maximum drive intensity percentage calculated in operation 614 is less than 100% (93.45% for the first color sensor and 93.40% for the second color sensor). Therefore, in operation 616, the calculated adjusted drive intensity is scaled to create the full range of adjusted drive intensity values ​​from 0 to 100% of the maximum drive intensity. Another typical table 718 containing the scaled adjusted drive intensity values ​​is shown in Figure 7H. As shown, the previously unscaled adjusted drive intensity values ​​are scaled to 100%, so they become equal to 3200, covering the full range of achievable drive intensity for the primary electrical input parameters (e.g., the maximum PWM duty cycle supported to drive the LEDs). Note that while the examples in Figures 7A to 7H are scaled up in operation 616, in certain embodiments, the adjusted drive intensity may be scaled down. Generally, the adjusted drive strength value can be scaled using the following formula: Scaled adjusted drive % = (a) × (adjusted drive %) In the above equation, "a" is the scaling factor determined by the following equation. a = (maximum drive) / (adjusted maximum drive)

[0052] When scaled, the scaled and adjusted drive values ​​are mapped to previously correlated and adjusted drive intensities and unscaled drive intensities, as well as drive intensity percentages, adjusted color sensor Y values ​​(for one or more sensors), target output luminous flux values, and output setpoints (e.g., data found in representative Table 712). A representative Table 720 illustrating the above-described scaled mapping is shown in Figure 7I for reference.

[0053] Using a scaled mapping (e.g., data found in representative table 720), the final relationship between a percentage-based output setpoint and a scaled and adjusted drive intensity percentage can be determined for a particular preset color. Thus, in operation 618, a fourth polynomial fit, i.e., a fourth function, is calculated to model the relationship between the output setpoint and the scaled and adjusted drive intensity percentage, thereby yielding two fitting parameters in general. A representative graph 722 of this relationship is shown in Figure 7J, which shows the output setpoint plotted along the X-axis and the scaled and adjusted drive intensity percentage plotted along the Y-axis. The two fitting parameters derived from the modeled relationship enable a customized conversion from a desired output setpoint of the light engine 208 to an adjusted drive intensity of the primary electrical input parameter of the light engine 208, thereby allowing the light engine 208 to produce illumination light with a perceived brightness matching the desired output setpoint. As a result, when a user, such as a surgeon, adjusts the light engine 208 to a desired output setting while using a surgical system equipped with a lighting device, the observed brightness of the light engine 208 corresponds to the output setting adjustment.

[0054] In summary, embodiments of this disclosure relate generally to systems and methods for calibrating light-emitting diode (LED) light engines, and more particularly to systems and methods for calibrating LED light engines that facilitate the use of dimensionless output setpoints that reflect the observed brightness of illumination. The methods and systems described herein address shortcomings of certain existing LED lighting systems and adjust the observed brightness non-linearly and non-intuitively by adjusting a desired output setting of the light engine. Accordingly, the methods and systems described herein can be used to calibrate a light engine such that the observed brightness of the generated illumination light corresponds linearly to an increase or decrease in the output setpoint due to user input.

[0055] As used herein, the phrase “at least one of” the list of items refers to any combination of these items, including one element belonging to it. For example, “at least one of a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc or any other order of a, b, and c).

[0056] The above description is provided so that any person skilled in the art can practice the various embodiments described herein. Various modifications to these embodiments will be readily apparent to a person skilled in the art, and the general principles defined herein may be applicable to other embodiments. Accordingly, the claims are not intended to be limited to the embodiments shown herein, but rather the full scope consistent with the language of the claims should be recognized.

[0057] In the claims, references to elements in the singular are not intended to mean “one and only one” unless specifically provided otherwise, but rather “one or more.” Unless specifically provided otherwise, the term “several” refers to one or more. All structural and functional equivalents to elements of various aspects described throughout this disclosure, known to or to those skilled in the art, are expressly incorporated by reference herein and are intended to be included in the claims. Furthermore, nothing disclosed herein is intended to be dedicated to the public, whether such disclosure is expressly enumerated in the claims or not. No element of the claims should be construed under Section 112(f) of the U.S. Patent Act unless the element is expressly enumerated using the phrase “means for…” or, in the case of a method claim, the element is enumerated using the phrase “steps for…” Where used herein, “exemplary” means “to serve as an example, case, or illustration.” Any embodiment described herein as “exemplary” should not necessarily be construed as being preferable or advantageous to any other embodiment.

[0058] Exemplary Embodiments Embodiment 1: A method for generating calibrated illumination light using an illumination system having a light engine, comprising receiving a user input corresponding to a dimensionless output setpoint of the illumination system, and mapping the dimensionless output setpoint to a corresponding adjusted drive intensity of a light engine input using mapping, wherein the mapping obtains a first set of data relating to the light engine, the first set of data including measured output luminous flux data and color sensor luminance measurements of the light engine, wherein the measured output luminous flux data and color sensor luminance measurements correspond to drive intensity data of a light engine input parameter, and between the measured output luminous flux data and the drive intensity data The method is derived by determining a first relationship, determining a second relationship between measured output luminous flux data and a color sensor luminance measurement, determining a third relationship between drive intensity data and a color sensor luminance measurement, and determining a fourth relationship between a dimensionless output setpoint and drive intensity data of a light engine input parameter, wherein the fourth relationship enables the conversion of the dimensionless output setpoint to a corresponding adjusted drive intensity of a light engine input parameter for driving the light engine to generate illumination light having a desired output luminous flux, and driving the light engine at the adjusted drive intensity for generating illumination light having a desired output luminous flux. According to embodiment (1), a method for generating calibrated illumination light using the light engine of a lighting system, wherein the method is Obtaining a first set of data relating to the light engine, wherein the first set of data includes measured output luminous flux data and color sensor luminance measurements of the light engine, and the measured output luminous flux data and color sensor luminance measurements correspond to drive intensity data of the light engine input parameters. To determine a first mapping between the measured output luminous flux data and the driving intensity data, To determine a second mapping between the measured output luminous flux data and the color sensor luminance measurement value, Based on the first mapping and the second mapping, a third mapping is determined between the drive intensity data and the color sensor brightness measurement value. Based on the third mapping, a fourth mapping is determined between a plurality of dimensionless output setpoints of the lighting system and the drive intensity data, Receiving one of the aforementioned dimensionless output setting values ​​from user input, Using the fourth mapping, one of the multiple dimensionless output setting values ​​is matched to the corresponding drive intensity of the light engine input parameter, Using the aforementioned light engine, to generate illumination light having a desired output luminous flux and This method includes [something]. According to embodiment (2), the first mapping corresponds to a polynomial fitting between the measured output luminous flux data and the drive intensity data. According to embodiment (3), the second mapping corresponds to a polynomial fitting between the measured output luminous flux data and the color sensor luminance measurement value. According to embodiment (4), the third mapping corresponds to a polynomial fitting between the drive intensity data and the color sensor brightness measurement value. According to embodiment (5), the fourth mapping corresponds to a polynomial fitting between the plurality of dimensionless output setting values ​​and the drive intensity data. According to embodiment (6), the first mapping is used to estimate the maximum output luminous flux of the light engine. According to embodiment (7), the maximum output luminous flux of the light engine is used to determine a range of target output luminous flux values, where each target output luminous flux value corresponds to one of the plurality of dimensionless output setting values. According to embodiment (8), the second mapping is used to determine the adjusted color sensor luminance values, each of which corresponds to one of the target output luminous flux values ​​across the entire range. According to embodiment (9), the third mapping is used to determine the adjusted drive intensity corresponding to each of the adjusted color sensor luminance values. According to embodiment (10), the adjusted drive intensity is scaled to correspond to the target output luminous flux value over the entire range. According to embodiment (11), determining the second mapping between the measured output luminous flux data and the color sensor luminance measurement value is independent of the color of the light generated by the light engine. According to embodiment (12), determining the first mapping, the third mapping, and the fourth mapping depends on the color of the light generated by the light engine.

Claims

1. A method for generating calibrated illumination light using the light engine of a lighting system, wherein the method is Obtaining a first set of data relating to the light engine, wherein the first set of data includes measured output luminous flux data and color sensor luminance measurements of the light engine, and the measured output luminous flux data and color sensor luminance measurements correspond to drive intensity data of the light engine input parameters. Determining a first mapping between the measured output luminous flux data and the driving intensity data, To determine a second mapping between the measured output luminous flux data and the color sensor luminance measurement value, Based on the first mapping and the second mapping, a third mapping is determined between the drive intensity data and the color sensor brightness measurement value. Based on the third mapping, a fourth mapping is determined between a plurality of dimensionless output setting values ​​of the lighting system and the drive intensity data. Receiving one of the aforementioned multidimensional output setting values ​​from user input, Using the fourth mapping, one of the plurality of dimensionless output setting values ​​is matched to the corresponding drive intensity of the light engine input parameter, To generate illumination light having a desired output luminous flux in a manner that linearly corresponds to an increase or decrease in the light engine input parameter, Includes, Determining the first mapping involves fitting a first polynomial to model the relationship between the measured output luminous flux data and the drive intensity data, estimating the maximum output luminous flux of the light engine corresponding to the maximum drive intensity value from the first polynomial, and determining a target output luminous flux value for the entire range based on the maximum output luminous flux of the light engine. Determining the second mapping involves fitting a second polynomial to model the relationship between the measured output luminous flux data and the color sensor luminance measurement, and determining from the second polynomial a tuned color sensor luminance value corresponding to one of the target output luminous flux values ​​over the entire range. Determining the third mapping includes fitting a third polynomial to model the relationship between the drive intensity data and the color sensor brightness measurement value, determining the adjusted drive intensity corresponding to the adjusted color sensor brightness value from the third polynomial, and calculating the drive intensity percentage of the adjusted drive intensity value relative to the maximum drive intensity value. Determining the fourth mapping involves fitting a fourth polynomial to model the relationship between the plurality of dimensionless output setting values ​​and the drive intensity data, A method for matching one of the plurality of dimensionless output setting values ​​to the corresponding drive intensity of the light engine input parameter using the fourth mapping, comprising generating a fitting parameter for converting one of the plurality of dimensionless output setting values ​​to the corresponding drive intensity of the light engine input parameter.

2. The method according to claim 1, wherein the adjusted drive intensity is scaled to correspond to the target output luminous flux value over the entire range.

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