System and method for controlled lighting of light emitting diodes

Abstract

Methods and systems for controlled illumination of LEDs are disclosed. An example system includes: a plurality of LEDs; an LED controller; a current buffer adapted to receive an input bias level signal from the LED controller, wherein a group of LEDs to be controlled together are connected in parallel with each other in a circuit having the current buffer; and at least one current limiting resistor connected in the circuit having the plurality of LEDs and the current buffer. These systems and methods are adapted to control illumination of the LEDs by applying a constant voltage to the circuit based on the input bias level signal, thereby controlling illumination of light emitting diodes without using pulse width modulation. Crosstalk interference to RFID components due to pulse width modulation is thereby avoided.

Description

Technical Field

[0001] The present disclosure relates to systems and methods for controlled lighting of light emitting diodes (LEDs). Background Art

[0002] Various ways of controlling the lighting of LEDs have been implemented for various applications. For example, in series control, multiple LEDs are connected in series and driven by a single LED driver. This setup is simple; however, high voltages may be required; and if one LED in the array fails, the entire group fails.

[0003] In another example, a multi-channel LED driver is used to control individual LEDs through individual channels. Although this device allows individualized control, the control signals of the individual channels may have time delays, which may cause time delays in the illumination of different LEDs that are intended to be illuminated simultaneously.

[0004] For example, LED lighting has been used in ophthalmic surgical systems. LED lighting has been used to indicate the status of an instrument port, indicating, for example, whether the instrument port is available for an instrument to be connected, whether the instrument is properly connected to the instrument port, whether the properly connected instrument is ready for use, etc. Example systems for instrument identification and associated lighting are described and shown in U.S. Patent No. 7,443,296 and U.S. Patent No. 7,551,077, the entire disclosures of which are incorporated herein by reference. Such a system can use a radio frequency identification (RFID) tag in an instrument with an RFID antenna at the instrument port. The connection status can be determined based on the RFID tag and then indicated with an LED.

[0005] In some existing systems, pulse width modulation is used to control LEDs. However, pulse width modulation may cause crosstalk interference between the LED driver circuit and the RFID antenna near the LED driver circuit. Since the RFID components are located near the LED circuit system, the high-order harmonics of the pulse width modulation signal may affect the RFID signal.

[0006] Therefore, there is a continuing need for improved systems and methods for controlled illumination of LEDs. Summary of the invention

[0007] The present disclosure relates to improved systems and methods for controlled lighting of LEDs.

[0008] In some example embodiments, an instrument identification system for an ophthalmic surgical system includes: an RFID antenna; a plurality of LEDs; a light emitting diode controller; a current buffer connected to the light emitting diode controller and adapted to receive an input bias level signal from the light emitting diode controller, wherein the LEDs of the plurality of LEDs are connected in parallel with each other in a circuit having the current buffer; and at least one current limiting resistor connected in the circuit having the plurality of LEDs and the current buffer; wherein the system is adapted to control the illumination of the LEDs by applying a constant voltage to the circuit based on the input bias level signal, thereby controlling the illumination of the light emitting diodes without using pulse width modulation.

[0009] In some example embodiments, the LEDs of the plurality of LEDs may be arranged in a ring. The RFID antenna may be circular. The LEDs of the plurality of LEDs may be arranged in a ring around the RFID antenna. The light emitting diode controller may include a digital-to-analog converter.

[0010] In some example embodiments, the system includes a plurality of LED circuits, wherein the LEDs in the circuits are connected in parallel with each other. The system may include one, two, three, or more such LED circuits. In one example, a first plurality of LEDs in a first circuit may emit a first color, a second plurality of LEDs in a second circuit may emit a second color, and a third plurality of LEDs in a third circuit may emit a third color. For example, the first color, the second color, and the third color may be red, green, and blue, respectively.

[0011] In some example embodiments, each light emitting diode has at least one dedicated current limiting resistor connected in series with the light emitting diode and in parallel with the remaining LEDs in the same circuit. In some example embodiments, at least one current limiting resistor is connected in series with all LEDs in the same circuit.

[0012] In some example embodiments, a system for controlled lighting of LEDs includes: a plurality of LEDs; a light emitting diode controller; a current buffer connected to the light emitting diode controller and adapted to receive an input bias level signal from the light emitting diode controller, wherein the LEDs of the plurality of LEDs are connected in parallel with each other in a circuit having the current buffer; and at least one current limiting resistor connected in the circuit having the plurality of LEDs and the current buffer; wherein the system is adapted to control lighting of the LEDs without using pulse width modulation.

[0013] In some example embodiments, a method for controlled lighting of LEDs includes: sending an input bias level signal from a light emitting diode controller to a current buffer; and, based on the input bias level signal, providing a constant bias voltage level to a circuit including a plurality of LEDs, wherein the LEDs in the circuit are connected in parallel with each other.

[0014] The above-described examples and other examples will be understood by those of ordinary skill in the art based on this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings illustrate examples of the systems and methods disclosed herein and, together with the description, serve to explain the principles of the disclosure.

[0016] Figure 1 is a block diagram illustrating components of an example system according to the present disclosure.

[0017] Figure 2 is a schematic diagram illustrating components of an example system according to the present disclosure.

[0018] Figure 3 is a schematic diagram illustrating components of another example system according to the present disclosure.

[0019] The drawings can be better understood with reference to the following detailed description. DETAILED DESCRIPTION

[0020] For the purpose of explaining the principles of the present disclosure, reference is made to the accompanying drawings, and specific language is used to describe these drawings. However, it should be understood that the reference to certain examples is not intended to limit the scope of the present disclosure. Those skilled in the art in the technical field involved in the present disclosure are generally fully able to envision any changes and further modifications to the described example systems, devices, apparatuses and methods, as well as any further applications of the principles of the present disclosure. In particular, those skilled in the art are generally able to envision that the features, components and / or steps described with respect to an example of the present disclosure can be combined with the features, components and / or steps described with respect to other examples of the present disclosure, and can be modified and / or replaced. For simplicity, in some cases, in the accompanying drawings, the same reference numerals may be used to refer to the same or similar parts.

[0021] Figure 1is a block diagram illustrating components of an example system according to the present disclosure. The system may be implemented, for example, as an instrument identification system for an ophthalmic surgical system, which may be used for ophthalmic surgical procedures such as cataract surgery and / or retinal surgery. Except for the differences described herein, the ophthalmic surgical system may be similar to the ophthalmic surgical system shown and described in U.S. Patent No. 9,931,447 (the disclosure of which is incorporated herein by reference in its entirety), and / or known and used ophthalmic surgical systems, such as the AT-1000, available from Alcon Laboratories, Inc. (Fort Worth, Texas). Vision systems are available from Alcon Laboratories, Fort Worth, Texas. visual system, or any other ophthalmic surgical system suitable for use with the principles described herein.

[0022] The ophthalmic surgical system may include an ophthalmic surgical console housing a computer system and components for one or more ophthalmic surgical functions, a display screen, one or more external control devices (such as a foot switch), and a plurality of instruments that may be connected to the ophthalmic surgical console. The ophthalmic surgical console may have a fluidic box base to which the fluidic box may be mounted.

[0023] Instruments that may be connected to the ophthalmic surgical console may be used for any of a variety of functions useful in ophthalmic surgery. For example, such instruments may include one or more phacoemulsification instruments (e.g., for removing cataractous lenses), diathermy instruments, vitrectomy instruments, laser therapy instruments, lighting instruments, cutters, forceps, scissors, or any other type of instrument suitable for use in ophthalmic surgery.

[0024] An ophthalmic surgical console may have one or more instrument ports to which an instrument may be connected. Each instrument port may be configured for a specific type of instrument.

[0025] The instrument to be connected to the ophthalmic surgery console may have a connector for connecting to a suitable instrument port. The instrument connector may have machine-readable information that can be read by a reader of the ophthalmic surgery console when the instrument is connected to the instrument port. For example, each instrument may have a radio frequency identification (RFID) tag, and each instrument port of the ophthalmic surgery console may have an associated RFID antenna for reading the RFID tag of the connected instrument. Each instrument port of the ophthalmic surgery console may also have an indicator, such as a light emitting diode (LED) ring, to indicate the status of a particular port and / or instrument. For example, different colors or modes (e.g., always on or flashing) of an LED may be used to indicate whether an instrument port is available for an instrument to be connected, whether an instrument is correctly connected to an instrument port, whether a correctly connected instrument is available for use, etc. An example system for instrument identification and related lighting is described and illustrated in U.S. Patent No. 7,443,296 and U.S. Patent No. 7,551,077, the disclosure of which is incorporated herein by reference in its entirety.

[0026] exist Figure 1 In FIG. 3 , the RFID tag of the instrument to be connected to the ophthalmic surgical console is represented as the external RFID tag 32 . Figure 1 The remaining elements may be implemented within the ophthalmic surgical console itself.

[0027] The microcontroller 10 can be used to control the operation of RFID tag reading and LED lighting. In order to read the RFID tag 32 of the instrument connected to the instrument port of the ophthalmic surgical console, the microcontroller 10 can communicate with the RFID reader 22 through the I2C bus 12. As indicated by the microcontroller 10, the RFID reader 22 sends an RFID discovery signal through the RF circuit 24 and the RFID antenna 30 to read any connected external RFID tags 32. The RFID antenna 30 is located at the instrument port, adjacent to the location where the external RFID tag 32 of the instrument will be located when the instrument is connected to the instrument port. When the instrument is connected to the instrument port, the external RFID tag 32 of the instrument is within the sensing distance of the RFID antenna. The sensing distance can be, for example, about 10 mm to about 50 mm, and can vary with the RF power of the RFID reader 22 and / or the design of the RFID antenna 30 or the RFID tag 32.

[0028] When the RFID reader 22 detects an external RFID tag, the RFID reader 22 reads information from the RFID tag. The information is transmitted to the microcontroller 10.

[0029] The microcontroller 10 receives and verifies the external RFID tag information, and then based on the information, sends one or more control commands to the associated LED controller 42 to appropriately illuminate the LED to indicate the status of the instrument port and / or instrument. The microcontroller 10 can communicate with the LED controller 42 via the I2C bus 12. The LED controller 42 may include a digital-to-analog converter (DAC).

[0030] To illuminate the desired LED, the LED controller 42 sends a control voltage as an input bias level signal to the current buffer 44. The current buffer 44 may include a high current operational amplifier. The current buffer 44 receives the input bias level signal from the LED controller 42 and acts as a buffer to sink current from the parallel LEDs, as shown below in conjunction with Figure 2 and Figure 3 Described in more detail.

[0031] A plurality of LEDs 60 are connected in a circuit with a current buffer 44. At least one current limiting resistor 46 is connected in a circuit with the plurality of LEDs 60 and the current buffer 44. In the illustrated example, a red-green-blue (RGB) LED 60 is used. A single RGB LED 60 may actually include three LEDs: a red LED, a green LED, and a blue LED. In the illustrated example, a plurality of red LEDs are connected together in a first circuit with a current buffer 44; a plurality of green LEDs are connected together in a second circuit with a current buffer 44; and a plurality of blue LEDs are connected together in a third circuit with a current buffer 44. Other colors and groups of LEDs are possible.

[0032] In the illustrated example, the RGB LEDs 60 are arranged in a ring. The RFID antenna 30 may be circular, and the RGB LEDs 60 may be arranged in a ring around the RFID antenna 30.

[0033] In each LED circuit, the LEDs in the circuit are connected in parallel with each other. Figure 2 and Figure 3 As shown, LEDs can be connected to current limiting resistors in a variety of ways. Figure 1 Both approaches are shown together, but those skilled in the art will understand that only one of the two approaches needs to be used.

[0034] In the first example (in Figure 1 In the case of a parallel resistor mode 52), each LED has at least one dedicated current limiting resistor 54 connected in series with the LED and in parallel with the remaining LEDs in the same circuit. Figure 2 A schematic illustration is given in .

[0035] Figure 2 is a schematic diagram showing components of an example system according to the present disclosure. Multiple RGB LEDs 60 are used together in any suitable number. The numbers -1 to -n are used in the figures to indicate the first to nth items in a group of items. Figure 2 In the example shown, multiple red LEDs 60R-1 to 60R-n are connected together in a first circuit having a current buffer 44; multiple green LEDs 60G-1 to 60G-n are connected together in a second circuit having a current buffer 44; and multiple blue LEDs 60B-1 to 60B-n are connected together in a third circuit having a current buffer 44.

[0036] exist Figure 2 In the example of , each LED has at least one dedicated current limiting resistor connected in series with the LED and in parallel with the remaining LEDs in the same circuit. Each red LED 60R has at least one dedicated current limiting resistor 54R connected in series with the red LED 60R and in parallel with the remaining red LEDs in the same circuit. For example, the red LED 60R-1 has a dedicated current limiting resistor 54R-1 connected in series with it and in parallel with the remaining red LEDs in the same circuit, and the red LED 60R-n has a dedicated current limiting resistor 54R-n connected in series with it and in parallel with the remaining red LEDs in the same circuit. Each green LED 60G has at least one dedicated current limiting resistor 54G connected in series with the green LED 60G and in parallel with the remaining green LEDs in the same circuit. For example, green LED 60G-1 has a dedicated current limiting resistor 54G-1 connected in series with it and in parallel with the remaining green LEDs in the same circuit, while green LED 60G-n has a dedicated current limiting resistor 54G-n connected in series with it and in parallel with the remaining green LEDs in the same circuit. Each blue LED 60B has at least one dedicated current limiting resistor 54B connected in series with it and in parallel with the remaining blue LEDs in the same circuit. For example, blue LED 60B-1 has a dedicated current limiting resistor 54B-1 connected in series with it and in parallel with the remaining blue LEDs in the same circuit, while blue LED 60B-n has a dedicated current limiting resistor 54B-n connected in series with it and in parallel with the remaining blue LEDs in the same circuit.

[0037] In the second example (in Figure 1In the series resistor mode 56, at least one current limiting resistor 58 is connected in series with all LEDs in the circuit. Figure 3 A schematic illustration is given in .

[0038] Figure 3 is a schematic diagram showing components of another example system according to the present disclosure. Figure 2 As in the example, multiple RGB LEDs 60 are used together in any suitable number, and numbers -1 to -n are used to indicate the first to nth items in a group of items. Figure 2 Similar to the example shown, Figure 3 In the example shown, multiple red LEDs 60R-1 to 60R-n are connected together in a first circuit having a current buffer 44; multiple green LEDs 60G-1 to 60G-n are connected together in a second circuit having a current buffer 44; and multiple blue LEDs 60B-1 to 60B-n are connected together in a third circuit having a current buffer 44.

[0039] exist Figure 3 In the example of FIG. 5 , at least one current limiting resistor is connected in series with all LEDs in the circuit. Each circuit having red LEDs 60R-1 to 60R-n has at least one current limiting resistor 58R connected in series with all LEDs in the circuit. Each circuit having green LEDs 60G-1 to 60G-n has at least one current limiting resistor 58G connected in series with all LEDs in the circuit. Each circuit having blue LEDs 60B-1 to 60B-n has at least one current limiting resistor 58B connected in series with all LEDs in the circuit.

[0040] The current limiting resistor can be selected based on the LED forward voltage. In the example, the forward voltage of the red LED is 2.0V, while the forward voltage of the green or blue LED is 3.1V. The current limiting resistor is related to the LED forward voltage according to the following formula:

[0041] R(current limiting resistor)=(V S (Power supply voltage) -V f (LED forward voltage)) / current

[0042] In use, the LED controller 42 sends an input bias level signal to the current buffer 44. The current buffer 44 receives the input bias level signal from the LED controller 42. Based on the input bias level signal, a constant voltage is applied to a circuit including multiple LEDs, such as a circuit with a single color LED. The current buffer 44 acts as a buffer that sinks current from the parallel LEDs in the circuit.

[0043] Those of ordinary skill in the art will recognize that the systems and methods disclosed herein have one or more advantages over existing methods. For example, compared to existing methods, the systems and methods disclosed herein are suitable for controlling the illumination of LEDs without the use of pulse width modulation. In LED driving and dimming methods, some methods such as pulse width modulation may cause crosstalk between the LED driver circuit and the RFID antenna near the LED driver circuit. Because the RFID components are located near the LED circuit system, the higher harmonics of the pulse width modulated signal may affect the RFID signal. Those of ordinary skill in the art will recognize that the systems and methods disclosed herein are suitable for controlling the illumination of LEDs without the use of pulse width modulation, and therefore there is no crosstalk and interference that may be associated with pulse width modulation.

[0044] In addition, those skilled in the art will recognize that the systems and methods disclosed herein provide a simple and effective LED brightness control scheme using linear control. Conventional DACs may have a current limit of about 10mA to 20mA for each port. This is insufficient to bear the high current absorption required for multiple LEDs arranged in parallel. Typical indicator LEDs each have a forward current of 20mA to 25mA. In the case of multiple LEDs arranged in parallel, the current absorption requirement may be about 100mA to 200mA. As disclosed herein, current buffers provide high current absorption to facilitate the illumination of multiple LEDs without pulse width modulation. LEDs in a single circuit can be lit simultaneously and efficiently.

[0045] It will be appreciated by those skilled in the art that the embodiments encompassed by the present disclosure are not limited to the specific exemplary embodiments described above. In this regard, although a number of illustrative embodiments have been shown and described, various modifications, changes, and substitutions may be contemplated in the foregoing disclosure. It should be understood that such changes may be made to the foregoing without departing from the scope of the present disclosure. Accordingly, it should be understood that the appended claims should be described broadly and in a manner consistent with the present disclosure.

Claims

1. An instrument identification system for an ophthalmic surgical system, the instrument identification system comprising: Radio frequency identification RFID antenna; a plurality of light emitting diodes; Light emitting diode controller; a radio frequency identification (RFID) reader coupled to the radio frequency identification (RFID) antenna; a microcontroller coupled to the LED controller and the RFID reader, the microcontroller being programmed to receive and verify information from the RFID reader, and the microcontroller being further programmed to send control commands to the LED controller based on the received and verified information; a current buffer connected to the LED controller and adapted to receive an input bias level signal from the LED controller, wherein the plurality of LEDs are connected in parallel with each other in a circuit having the current buffer; and at least one current limiting resistor connected in the circuit having the plurality of light emitting diodes and the current buffer; wherein the system is adapted to control the illumination of the light emitting diode by applying a constant voltage to the circuit based on the input bias level signal, thereby controlling the illumination of the light emitting diode without using pulse width modulation, wherein the plurality of light emitting diodes connected in parallel with each other in the circuit are a first plurality of light emitting diodes connected in a first circuit, and the system further comprises a second plurality of light emitting diodes connected in parallel with each other in a second circuit and a third plurality of light emitting diodes connected in parallel with each other in a third circuit, the first plurality of light emitting diodes emit a first color, the second plurality of light emitting diodes emit a second color, and the third plurality of light emitting diodes emit a third color, a first circuit of the first plurality of light emitting diodes having at least one first current limiting resistor connected in series with all of the light emitting diodes in the first plurality of light emitting diodes, a second circuit of the second plurality of light emitting diodes having at least one second current limiting resistor connected in series with all of the light emitting diodes in the second plurality of light emitting diodes, and a third circuit of the third plurality of light emitting diodes having at least one third current limiting resistor connected in series with all of the light emitting diodes in the third plurality of light emitting diodes, and Each of the at least one first current limiting resistor is selected based on the LED forward voltage of the first plurality of light-emitting diodes, each of the at least one second current limiting resistor is selected based on the LED forward voltage of the second plurality of light-emitting diodes, and each of the at least one third current limiting resistor is selected based on the LED forward voltage of the third plurality of light-emitting diodes.

2. The instrument identification system for an ophthalmic surgical system according to claim 1, wherein: The light emitting diodes of the plurality of light emitting diodes are arranged in a ring shape.

3. The instrument identification system for an ophthalmic surgical system according to claim 1, wherein: The radio frequency identification RFID antenna is circular.

4. The instrument identification system for an ophthalmic surgical system according to claim 1, wherein: The light emitting diodes of the plurality of light emitting diodes are arranged in a ring shape around the radio frequency identification RFID antenna.

5. The instrument identification system for an ophthalmic surgical system according to claim 1, wherein: The light emitting diode controller includes a digital-to-analog converter.

6. The instrument identification system for an ophthalmic surgical system according to claim 1, wherein: The first color is red, the second color is green, and the third color is blue.

7. A method for controlled illumination of a light emitting diode, the method comprising: receiving and verifying information at the microcontroller from a radio frequency identification (RFID) reader coupled to a radio frequency identification (RFID) antenna; sending control commands from the microcontroller to a light emitting diode controller based on the received and verified information; sending an input bias level signal from the light emitting diode controller to a current buffer in response to the control command; as well as applying a constant voltage to a circuit including a plurality of light emitting diodes based on the input bias level signal, wherein the light emitting diodes in the circuit are connected in parallel with each other, wherein the plurality of light emitting diodes include a first plurality of light emitting diodes connected in parallel with each other in a first circuit, a second plurality of light emitting diodes connected in parallel with each other in a second circuit, and a third plurality of light emitting diodes connected in parallel with each other in a third circuit, the first plurality of light emitting diodes emit a first color, the second plurality of light emitting diodes emit a second color, and the third plurality of light emitting diodes emit a third color, a first circuit of the first plurality of light emitting diodes having at least one first current limiting resistor connected in series with all of the light emitting diodes in the first plurality of light emitting diodes, a second circuit of the second plurality of light emitting diodes having at least one second current limiting resistor connected in series with all of the light emitting diodes in the second plurality of light emitting diodes, and a third circuit of the third plurality of light emitting diodes having at least one third current limiting resistor connected in series with all of the light emitting diodes in the third plurality of light emitting diodes, and Each of the at least one first current limiting resistor is selected based on the LED forward voltage of the first plurality of light-emitting diodes, each of the at least one second current limiting resistor is selected based on the LED forward voltage of the second plurality of light-emitting diodes, and each of the at least one third current limiting resistor is selected based on the LED forward voltage of the third plurality of light-emitting diodes.

Images