DE102018130376A1 - Method for controlling an ophthalmic handpiece, ophthalmic surgical device and system - Google Patents

Abstract

The invention relates to a method for controlling an ophthalmic surgical handpiece (3) which can be driven by means of a piezo-based drive unit (2) for machining an eye lens, comprising: is provided by a control signal (5, 6), - detecting an electrical operating state variable (10) dependent on an operating state of the handpiece (3), and - generating a value of the control signal (5, 6) depending on the electrical operating state variable (10). It is proposed that, before an end of usability for the intended use of the handpiece (3) has been reached, forecast data for a remaining intended usability of the handpiece (3) until the end of usability at least depending on the value of the control signal (5, 6) and / or the electrical operating state variable (10) can be determined and depending on the forecast data a corresponding statement for informing a user of the handpiece (3) is provided. The invention also relates to an ophthalmic surgical device (37) and an ophthalmic surgical system (35).

Description

Technical field

The invention relates to a method for controlling an ophthalmic surgical handpiece which can be driven by means of a piezo-based drive unit for machining an eye lens, comprising: applying an AC voltage to the drive unit which is provided by a controllable AC voltage generator as a function of at least one control signal for controlling the AC voltage generator, and detecting one electrical operating state variable dependent on an operating state of the handpiece by means of an operating state sensor, and generating a value of the at least one control signal as a function of the at least one detected electrical operating state quantity by means of a generator control unit. The invention further relates to an ophthalmic surgical device with an ophthalmic surgical handpiece which can be driven by means of a piezo-based drive unit for processing an eye lens and a control device which can be connected to the ophthalmic surgical handpiece at least in an intended operation. The control device has a controllable AC voltage generator which is designed to provide an AC voltage for the piezo-based drive unit as a function of at least one control signal for controlling the AC voltage generator. The control device also has at least one operating state sensor for detecting an electrical operating state variable dependent on an operating state of the handpiece and a generator control unit for providing a value of the at least one control signal as a function of a value of the at least one detected electrical operating state variable. Finally, the invention also relates to an ophthalmic surgical system for processing an eye lens, with at least one irrigation device, an aspiration device and an ophthalmic surgical device.

State of the art

Ophthalmic surgical devices, in particular handpieces and control devices therefor, ophthalmic surgical systems with ophthalmic surgical devices and methods for controlling them are known in the prior art. They are used in particular to treat lens opacification of an eye lens in a living being, for example a human or an animal. Such lens clouding is also referred to in medicine as cataracts or cataracts. A common technique for treating lens opacity is phacoemulsification. The clouded eye lens is broken up or emulsified into small components by means of a mechanically vibrating needle in an ultrasound range, which is often designed as a hollow needle and has a cutting tip at its front end, in such a way that these components by means of a suction device, for example through a suction channel, can be provided by the needle, can be sucked off. An operator then uses an artificial eye lens to replace the eye lens removed in this way.

An important component for performing phacoemulsification is the ophthalmic surgical handpiece, hereinafter also referred to as a handpiece, which has the aforementioned needle. In order to drive the needle as intended to carry out the processing of the eye lens by executing mechanical vibrations in the ultrasound range in the desired manner, the handpiece generally comprises a drive unit which has one or more piezoelectric elements. This forms a piezo-based drive unit. Such a drive unit uses the effect that the piezoelectric elements to which an electrical voltage is applied change their mechanical dimensions, for example a length or the like. The needle is mechanically connected to the piezo-based drive unit, in particular its piezoelectric elements, in order to be able to achieve the desired drive effect by means of the piezo-based drive unit in the intended operation.

The piezo-based drive unit has electrical connections at which electrical energy can be applied to it so that its piezoelectric elements provide a desired mechanical movement for the needle. To drive the piezo-based drive unit, the piezo-based drive unit is generally supplied with an electrical alternating voltage, the frequency of which generally corresponds to the frequency with which the needle is to vibrate.

The control device, to which the handpiece is coupled at least in the intended operation and which for this purpose comprises an adjustable AC voltage generator, is used to provide the AC voltage. The AC voltage generator is generally controlled in such a way that the AC voltage is provided at a frequency such that the needle vibrates in the ultrasound range. An ophthalmic surgical handpiece, a control device and a method for control are, for example, by DE 10 2011 114 584 B3 as well as through the DE 40 08 594 A1 disclosed.

With regard to the handpieces, it has been found that the drive effect of the piezo based drive unit of the handpiece decreases depending on the time and / or the intended use, i.e. aging occurs. Aging can occur, for example, if a handpiece used during an operation has to be sterilized before it can be used again as intended. It has been shown that with an increasing number of sterilizations, the drive effect of the piezo-based drive unit wears off, that is, the aging increases.

However, aging need not only be caused by sterilization. It can also occur with almost new and little used handpieces, especially if they have been stored unused for a long period before use. The aging can also be influenced by other effects, such as thermal stress during the intended operation of the handpiece, mechanical effects during storage and / or during the intended operation of the handpiece, depolarization over time or the like. Aging can also result from the interaction of one or more of the above-mentioned mechanisms of action.

It has also been shown that the aging of the piezo-based drive unit is determined in particular by aging of the piezoelectric elements. As a result, the mechanical vibration provided by the needle of the handpiece decreases with a given alternating voltage with increasing use of the handpiece. As a result, the intended use or functionality of the handpiece and also the performance of the handpiece can be impaired. Problems that may arise due to aging can result in malfunctions in the handpiece or also through delays, for example while performing an operation or treatment on the eye lens, if the handpiece is no longer able to provide its full functionality or performance, for example.

Overall, it proves to be disadvantageous that the user, in particular the surgeon, has no information as to how long the handpiece can still be used as intended until it has to be replaced. This information can be important for performing operations, especially since it can be a hindrance, if not dangerous, if a handpiece needs to be replaced during the operation. Not only can this disrupt the operation as a whole, but there can also be further disadvantages, particularly with regard to the quality of the operation.

Presentation of the invention

The invention is based on the object of developing a generic method, an ophthalmic surgical device and an ophthalmic surgical system in such a way that the user, in particular before the start of a respective operation, is provided with information about the remaining intended use of a respective handpiece.

As a solution, the invention proposes a method, an ophthalmic surgical device and an ophthalmic surgical system according to the independent claims.

Advantageous further developments result from features of the dependent claims.

With regard to a method of the generic type, the invention in accordance with a first aspect proposes in particular that, before an end of usability for the intended use of the handpiece has been reached, forecast data for a remaining intended usability of the handpiece until the end of usability depends at least on the value of the at least one control signal and / or the electrical operating state variable are determined and, depending on the forecast data, a corresponding statement is provided for informing a user of the handpiece.

With regard to a generic ophthalmic surgical device, the invention proposes, in accordance with a second aspect, in particular that it has an evaluation unit which is designed before a usability end for the intended usability of the handpiece has been reached, forecast data for a remaining intended usability of the handpiece until the end of usability to be determined at least depending on the value of the at least one control signal and / or the electrical operating state variable and, depending on the forecast data, to provide a corresponding statement for informing a user of the handpiece.

With regard to a generic ophthalmic surgical system, the invention in accordance with a third aspect proposes in particular that the ophthalmic surgical device is designed according to the invention.

A further independent aspect of the invention relates to a control device for an ophthalmic surgical handpiece which can be driven by means of a piezo-based drive unit for processing an eye lens, with a controllable one AC voltage generator which is designed to provide an AC voltage for the drive unit as a function of at least one control signal for controlling the AC voltage generator, at least one operating state sensor for detecting an electrical operating state variable which is dependent on an operating state of the handpiece and a generator control unit for providing a value of the at least one control signal as a function of the at least one detected electrical operating state variable. According to the invention, the control device comprises an evaluation unit which is designed before an end of usability for the intended use of the handpiece has been reached, forecast data for a remaining intended use of the handpiece until the end of usability, at least depending on the value of the at least one control signal and / or the electrical operating state variable to be determined and, depending on the forecast data, to provide corresponding information for informing a user of the handpiece.

Yet another independent aspect of the invention relates to a method for controlling an ophthalmic surgical handpiece that can be driven by means of a piezo-based drive unit for machining an eye lens, comprising: applying an AC voltage to the drive unit that is dependent on at least one control signal for control by a controllable AC voltage generator of the AC voltage generator is provided, detecting an electrical operating state variable which is dependent on an operating state of the handpiece by means of an operating state sensor, and generating a value of the at least one control signal as a function of the at least one detected electrical operating state variable by means of a generator control unit, wherein data about a communication connection between the handpiece and the control device be transmitted.

The invention is based on the idea that the control parameter for the AC voltage generator and the operating state signal of the handpiece can be determined by suitable evaluation to determine whether the handpiece can still be used as intended and which can be used to provide a corresponding or corresponding indication. By means of the information corresponding to the remaining usability, the user can be informed accordingly, for example by providing the user with a perceptible output of the information corresponding to the corresponding information. As a result, the user, for example an operator or a suitable staff, can receive information in good time before intended use, such as an operation, as to whether the handpiece can still be used for the planned processing. This has the advantage that the handpiece can be checked and selected accordingly before the start of machining, so that the operation can be carried out reliably without changing the handpiece, if possible. The user can thus be informed about the remaining intended usability of the handpiece before the end of usability and can thus plan his activity, in particular in relation to an operation. The user can thus particularly advantageously avoid having to replace the currently used handpiece while processing an eye lens. The user can be supported accordingly with the corresponding information, which makes it possible to provide the user with the information regarding the remaining intended usability.

In particular, it can be achieved that the user does not need to separately examine the operational readiness of the handpiece in this regard. In this sense, it can be provided, for example, that the surgeon can use the information available in accordance with the corresponding information to decide whether the handpiece must be replaced with a new handpiece before an operation begins. The surgeon can determine this, for example, on the basis of planning data for the intended operation. Taking these planning data into account, the surgeon can forecast or determine which remaining usability of the handpiece is required so that the desired operation can be carried out as completely as possible with a specific handpiece. Thus, the information corresponding to the remaining usability of the handpiece can significantly improve the reliability and use in relation to handpieces. Overall, this can have an advantageous effect on the operation carried out with the respective specific handpiece.

The intended usability includes, in particular, the intended use for removing the eye lens by processing or treating the subject's eye lens by the action of the processing needle of the handpiece on the eye lens. The intended use preferably also includes that the corresponding standardization is taken into account, for example IEC 60601, in particular Part 1, EN 61340-5-1, IEC 80601-2-58, ISO 10079, in particular Part 1, and / or similar. The intended usability also relates in particular to the Usability of the handpiece for the intended use in the removal of the living organ's eye lens. Thus, the intended usability preferably also includes operational readiness of the handpiece for the intended use, that is to say that when the eye lens is started to be processed, the control device does not immediately output the message that the handpiece must be replaced. Accordingly, the end of usability for the intended usability of the handpiece is preferably characterized in that under operating conditions which are necessary for performing the processing of the eye lens, the desired or required function can no longer be provided by the handpiece, for example because a value of the operating state variable is outside of a predetermined value range for this operating state variable, for example because the value of the operating state variable is too small and it is no longer possible to track the AC voltage by the AC voltage generator of the control device or, if appropriate, it is also not provided, or the like. The operating state variable can be a reverse voltage or a feedback voltage, which is provided by the piezo-based drive unit in response to an action of a predetermined alternating voltage.

The forecast data are preferably formed by at least one electrical signal. In particular, the forecast data can also include digital data. The forecast data are preferably determined or determined by the evaluation unit of the ophthalmic surgical device. For this purpose, the evaluation unit comprises, for example, an electronic circuit, a program-controlled computer unit and / or the like. The evaluation unit can be designed as a separate assembly of the ophthalmic surgical device. However, it can also be at least partially encompassed by another assembly of the ophthalmic surgical device, for example by the generator control unit or the like. Of course, the evaluation unit can also be spatially separate from the ophthalmic surgical device and be in communication with the latter. The evaluation unit can thus also be formed by a separate computer unit, for example a central office or the like.

In order to determine the forecast data, at least the control signal and preferably also the electrical operating state variable are made available for evaluation by the evaluation unit. In principle, however, the forecast data can already be determined or determined only on the basis of the control signal for the AC voltage generator or the electrical operating state variable. For this purpose, the evaluation unit can, for example, evaluate the control signal of the AC voltage generator and determine the forecast data from a change over time. As an alternative or in addition, this can also be provided for the electrical operating state variable. Of course, done together for the control signal and the electrical operating state variable. The forecast data can be determined using statistical methods. For this purpose, mean values, variances and / or the like can be determined. For this purpose, reference data can also be used, which can be stored, for example, in a memory unit of the control unit, in particular the evaluation unit. In addition, the reference data can of course also be provided at least partially by an external storage device via a communication link between this storage device and the control device or the evaluation unit. This makes it possible to provide the reference data centrally so that it can be easily maintained or updated. Furthermore, the reference data can be provided in this way for a plurality of different control devices or evaluation units. The reference data can be determined, for example, using one or more reference handpieces. The forecast data can also be determined taking into account a change in the supply voltage over time when used as intended. The forecast data can also be determined during commissioning (priming) of the handpiece connected to the control unit. Combinations of the aforementioned options can also be provided.

The corresponding information depending on the forecast data can be, for example, an electrical, optical, hydraulic, pneumatic or also haptic signal. The indication can also be a combination of one or more of the aforementioned signals. The indication can be determined from the forecast data by feeding the forecast data to a processing unit, for example a display device, which then determines the corresponding indication in such a way that, depending on the corresponding indication, a display of corresponding information that can be perceived by the user can be provided . In particular, a predicted number of operations that can be carried out by means of the handpiece and / or a predicted period of time for the intended use can be generated as the corresponding information. Thus, it can be provided that the corresponding indication of an aging state of the respective handpiece in% with respect to a maximum predicted service life. The Corresponding information can also indicate a forecast period for a still possible intended use under predeterminable conditions of use, in particular with regard to the intended use. The time period can be specified, for example, in minutes, in hours, in days or the like. However, the corresponding information can also indicate a predicted number of operations, sterilizations and / or the like that can still be carried out with the respective handpiece. Of course, combinations thereof or the like can also be provided. The corresponding indication can be displayed as information for the user by means of the display device, so that the user is informed, preferably at any time, about the predicted still usability of the handpiece. The information can be displayed optically by alphanumeric characters and / or also by a graphic representation, for example by means of a bar chart or the like.

The processing unit or the display device can be comprised by the ophthalmic surgical device, in particular by the control device. However, a separate processing unit or a separate display device can also be provided, which is in communication connection with the control device. A combination of these can also be provided. The processing unit or the display device preferably processes the forecast data in such a way that the desired display of the information can be achieved. This can depend on the display device, in particular on which medium the display device uses to display the information. For example, the display device can be designed for an optical, acoustic and / or haptic output of the information, the forecast data being processed in a suitable manner so that the desired output of the information can take place in accordance with the corresponding information. It is preferably provided that the type of output of the information can be set by the user, at least if the display device can provide different output options. For this purpose, the ophthalmic surgical device, in particular the control device and / or the processing unit or the display device, can comprise appropriate input means, by means of which the user can make a corresponding setting.

The control device can be designed as a unit which can be handled separately and which is arranged in a suitable space. The control device can be designed to be stationary or mobile. In particular, the control unit can of course also be a component of further, in particular ophthalmic, treatment devices. For example, the control device can have its own housing, which comprises its units or assemblies. In addition, the control device can also include an operating device or can be designed to connect such an operating device with which the control device or the handpiece connected to it can be operated in a predetermined manner. Finally, the control device can also have an output interface to which a display device can be connected in order to transmit the corresponding information to the display device and to display it. Basically, the display can be visual and / or acoustic and / or haptic. It is preferably selected in such a way that it can easily be grasped by the surgeon even during the intended operation, that is to say in particular during an operation.

In order to control the handpiece in a predetermined manner by means of the control device, it can be provided that the controllable alternating voltage generator provides an adjustable alternating voltage for the piezo-based drive unit of the handpiece. The AC voltage can be, for example, a sinusoidal or a rectangular AC voltage. It can have an amplitude in a range from approximately 15 V to approximately 35 V, preferably in a range from approximately 20 V to approximately 30 V. The adjustability of the AC voltage, in particular its amplitude and / or its frequency, can depend on how the piezo-based drive unit is designed, or how many piezoelectric elements the piezo-based drive unit comprises, how they are mechanically coupled to one another and how they are interconnected , for example in series, in parallel or the like. The piezo-based drive unit can have, for example, two, four or even six piezoelectric elements which are arranged in series connection, for example, with regard to their mechanical deflection. Electrically, a series connection, a parallel connection and also a combination thereof, for example in the manner of a matrix connection or the like, can be provided.

In addition, there is the possibility that at least one of the piezoelectric elements is not electrically coupled to the AC voltage generator and instead serves as an operating state sensor for detecting the electrical operating state variable. Nevertheless, this piezoelectric element is preferably mechanically coupled to the further piezoelectric elements. The piezoelectric elements can be arranged in a stack which is subjected, for example, to a predetermined compressive force. In this way, an operating point of the piezo-based drive unit can be set.

The controllable AC voltage generator is designed to provide the AC voltage as a function of the at least one control signal. The control signal can be a specification for the frequency of the AC voltage, for example. In addition, however, the control signal can also be a specification for an amplitude of the AC voltage. Combinations of these as well as other control parameters can also be used to set the AC voltage generator. At least for the frequency and the amplitude, separate control signals can also be provided. The AC voltage generator is preferably an electronic circuit which provides the AC voltage as a function of the at least one control signal. For this purpose, the AC voltage generator can be connected to an electrical energy source, which can comprise, for example, an accumulator, a power supply unit connected to an energy supply network and / or the like. To generate the AC voltage, the AC voltage generator can have suitable electronic switching elements with which the AC voltage can be set in accordance with the at least one control signal. For example, the AC voltage generator can comprise an analog power amplifier which is operated, for example, in the manner of a feedback amplifier stage. By setting a delay time in a feedback loop as a function of the at least one control signal, the frequency of the AC voltage can be set, for example. The amplitude of the AC voltage can be realized, for example, by an adjustable gain factor, which can also be set as a function of the at least one control signal. In addition, there is of course also the possibility of adjusting the amplitude of the AC voltage by adjusting a supply voltage of the AC voltage generator as a function of the at least one control signal. In this embodiment it can be provided that the amplitude of the AC voltage is directly dependent on the supply voltage of the AC voltage generator. To set the supply voltage, for example, a power supply unit or the like which can be set by means of the at least one control signal and which provides the supply voltage can be provided.

The operating state sensor serves to detect the electrical operating state variable which is dependent on the operating state of the handpiece. The operating state sensor can thus detect at least one electrical operating state variable, for example an electrical voltage, namely the feedback voltage that is provided by the piezo-based drive unit, or the like. In this case, the operating state sensor is preferably designed as a voltage sensor. In addition, as already explained above, the operating state sensor can also be formed by one or more piezoelectric elements. At least the amplitude of an alternating voltage as a first operating state and also the frequency as a second operating state can preferably be detected as electrical operating state variables. The at least one operating state sensor thus provides at least one corresponding sensor signal as an operating state signal, which can optionally also be made available in combination with a single or also with a plurality of recorded operating parameters of the handpiece. For example, in addition to an amplitude of the AC voltage recorded as an operating state variable, its frequency can also be provided with a single sensor signal using a voltage sensor.

If the AC voltage generator is deactivated for a detection period for detecting the electrical operating state variable, the mechanical natural frequency or resonance frequency of the handpiece can be determined by means of the frequency of the detected AC voltage. This can then be used to control the frequency of the AC generator. In addition, there is the possibility of obtaining a measure of the energy stored in the piezo-based drive unit by detecting the amplitude of the feedback voltage. This allows the state of aging to be determined, namely if additional data are available regarding the AC voltage previously provided by the AC voltage generator. This allows the evaluation unit to easily determine a measure of the aging or the remaining usability of the handpiece.

The control device further comprises the generator control unit, which is used to provide the at least one control signal as a function of the at least one detected electrical operating state variable. For this purpose, the at least one operating state sensor is coupled with the generator control unit in terms of communication technology, for example by being connected to it via a communication line or the like. The at least one sensor signal provided by the operating state sensor is thus available to the generator control unit. The generator control unit uses signal processing to determine the at least one control signal that is made available to the controllable AC voltage generator via a further communication connection. In this way, the generator control unit can predefine the AC voltage generator Control wise. The generator control unit can have an electronic circuit and / or a program-controlled computer unit in order to implement its function.

An operating unit can also be connected to the control unit, in particular to the generator control unit, which enables the user or the operator to influence the at least one control signal in a predeterminable manner, so that a predefinable operating state for the operation to be carried out can be set by means of the handpiece. The control signal can also be influenced while an operation is being carried out.

In addition, the generator control unit can also be used to control the AC voltage generator in such a way that the AC voltage generator provides operating pauses at predefinable time intervals in which no AC voltage is emitted. During these breaks in operation, a reaction of the piezo-based drive unit can then be detected by means of the operating state sensor in order to be able to detect the operating state of the handpiece, that is, in particular a mechanical operating state of the handpiece, as undisturbed as possible. In this way, for example, a mechanical resonance frequency of the handpiece can be determined during intended use in order to detect a change in the mechanical resonance frequency and to be able to control the generator control device accordingly for tracking. As a result, a high degree of efficiency can be achieved when machining the eye lens.

It can also be taken into account that it can be advantageous to be able to achieve complete emulsification of the eye lens in the shortest possible time. It is usually desirable to achieve a high degree of efficiency, which is why it is desirable to operate the piezo-based drive unit in the range of the mechanical resonance frequency of the handpiece. The mechanical resonance frequency of the handpiece including its needle can be precisely determined in the no-load condition, that is, outside of the intended use during an operation. However, as soon as the needle comes into contact with the eye lens to be emulsified, mass ratios change so that the mechanical resonance frequency is changed. It is therefore customary to control the controllable AC voltage generator in such a way that during an operation the handpiece or the piezo-based drive unit is operated as possible with the AC voltage in the range of a mechanical resonance frequency of the handpiece. This can be achieved with the generator control unit in conjunction with the operating state sensor connected to it.

Overall, the knowledge is used that the remaining usability of the handpiece can be predicted from the current control signal and / or the detected electrical operating state variable. After the remaining usability of the handpiece has been determined, the corresponding information can be determined from this and made available accordingly.

One development provides that the corresponding information is additionally provided as a function of a comparison of the at least one control signal and / or the electrical operating state variable with a predeterminable comparison value. The comparison value can be determined, for example, on the basis of statistical evaluations of a specifiable sample of handpieces or the like. However, the comparison value can also be determined taking into account permissible heating of the handpiece during intended use or the like. In addition, parameters of the control device, in particular of the AC voltage generator, can also be used to determine the comparison value, for example a maximum amplitude of the AC voltage or the like. The maximum amplitude can be determined, for example, depending on the supply voltage of the AC voltage generator. However, the comparison value can also be formed by a predetermined feedback voltage or the like. The predefined feedback voltage can also be a minimum feedback voltage. This option is particularly suitable if the comparison function is based on the evaluation of the electrical operating state variable. The comparison value can be used to determine the maximum intended use. The remaining usability can thus be determined on the basis of the comparison value by the evaluation unit. The comparison value can also be the supply voltage of the AC voltage generator, for example.

In addition, it is proposed that the control signal be adapted in discrete stages in accordance with an aging progress of the handpiece, the forecast data being determined on the basis of a number of the stages currently required for the intended use. With the control signal, for example, the amplitude of the AC voltage provided by the AC voltage generator can be set. It can be provided that the amplitude of the alternating voltage is set in predefinable steps by means of the control signal. Each level can correspond to a certain amount of tension, for example about 1 V, 1.5 V or the like. The voltage amount can be approximately the same for all stages. Depending on requirements, it can also be provided that voltage levels that differ from one another are assigned to the stages. The voltage level required in each case can be determined taking into account the currently recorded electrical operating state variable of the handpiece. If, for example, a value of the feedback voltage falls below a predetermined minimum value, the next stage can be activated by means of the control signal. The forecast data can thus be determined by counting the activated levels and comparing them with the maximum possible levels.

It is also proposed that data be transmitted via a communication link between the handpiece and the control device. In this development, the handpiece and the control device each have a corresponding communication unit, which allow the communication connection to be established wirelessly or also via a line. The communication link enables data, in particular identification data of the handpiece, to be exchanged between the handpiece and the control device. On the one hand, it is possible for the control device to provide data for the handpiece that, for example, should be stored in a handpiece-specific manner. In this way, for example, individual operating parameters or the like can be provided in the handpiece for the respective handpiece, so that the handpiece can also be combined in a simple manner with different control devices without requiring a large amount of calibration. For this purpose, the handpiece can have a data memory, in particular an electronic data memory. The data memory can be designed, for example, as an EEPROM. However, the control device can read out data from the data memory of the handpiece via the communication link. The data can include, for example, identification data of the handpiece. As a result, the handpiece can be individualized, so that the use of the handpiece in the control device or also from a control center which is connected to the control device via a further communication link can be traced.

A communication protocol for the communication connection can be selected such that the most interference-free transmission of the data can be realized. Error-redundant codes and the like can be provided for this purpose. In addition, of course, there is also the possibility of making the communication connection wireless. For this purpose, it is preferably provided that the communication connection is not only particularly immune to interference by the choice of a coding, but that it is also encrypted at the same time, so that no unauthorized third parties can access or make it difficult. The handpiece can initiate the communication connection. This can be done, for example, by connecting the handpiece to the control device or to its supply interface. In addition, it can of course be provided that the establishment of the communication connection is initiated by the control device when the handpiece is connected to the control device. Predefined protocols relating to handshake and the like can be used for the purpose of initiating the communication connection.

In addition, there is of course the possibility that the data memory includes data relating to the at least one control signal, so that the control device can adapt the at least one control signal in a simple manner for the control device or the AC voltage generator, in particular when starting up and initializing the handpiece. Of course, it can also be provided that a number of intended uses are stored in the data memory of the handpiece and that these data are updated by the control device after each intended use of the handpiece. As a result, information on current use is regularly available in the handpiece. However, the corresponding information can also be saved in the handpiece. As a result, the handpiece does not need to be put into operation to determine this information. The desired information can thus be available as soon as this information is read out.

The individualization of the handpieces also makes it possible to track different usabilities of the handpieces and, overall, to achieve a more uniform usability of several handpieces.

It is further proposed that the control device has a supply interface for the handpiece, which comprises the communication interface. As a rule, it is provided that the control device comprises the supply interface to which a supply interface of the handpiece can be connected so that the handpiece can be operated as intended. For this purpose, at least one line-bound connection is provided, by means of which the AC voltage provided by the AC voltage generator can be provided for the piezo-based drive unit of the handpiece. In addition, the supply interface can also include one or more lines, by means of which debris that arises during the processing of the eye lens is sucked off can be. Furthermore, a flushing line can also be provided, by means of which a corresponding flushing liquid for the operation can be supplied to the handpiece, in order, for example, to better remove the debris or the like. In addition, of course, other supply elements can also be provided if necessary.

It is also proposed that the AC voltage generator be deactivated at least during the detection of the electrical operating state variable. This has the advantage that the electrical operating state variable is essentially not influenced when it is detected by the AC voltage generator. For this purpose, the AC voltage generator can particularly advantageously be switched into a state of high impedance, so that its influence on the handpiece and in particular its piezo-based drive unit is as small as possible, preferably negligible. The AC voltage generator can be deactivated repeatedly at predeterminable times. For example, it can be provided that the deactivation takes place at a time interval of approximately 10 ms or the like. The deactivation itself can take place for a predeterminable period of time from approximately 400 μs to approximately 500 μs, preferably approximately 450 μs. At an operating frequency in the range of approximately 40 kHz, such a deactivation period is sufficient to be able to reliably detect the operating state variable.

The corresponding information is preferably provided additionally depending on handpiece-specific data read from the data memory, in particular identification data of the handpiece. The identification data can be provided at the same time as the corresponding information, so that this corresponding information can be recorded individually. In addition, it can be provided that additional data from a database are called up on the basis of the identification data of the handpiece and taken into account for determining the corresponding information. As a result, the determination of this corresponding information by the evaluation unit can be further improved. The additional data can include, for example, design features, operational features and / or the like of the handpiece.

It is further proposed that the supply voltage of the alternating voltage generator and / or a feedback voltage of the handpiece be used as the control signal as the control signal. The supply voltage of the AC voltage generator is an easily available quantity. It is available in the control unit, so that no separate detection means need to be provided. In addition, the amplitude of the AC voltage can be set in a simple manner by means of the supply voltage. It can be provided that the AC voltage generator provides the amplitude of the AC voltage depending on the supply voltage. The amplitude of the AC voltage can thus be adjusted by adjusting the supply voltage. The amplitude of the alternating voltage preferably corresponds approximately to the supply voltage. The supply voltage is usually a DC voltage that is applied to the AC voltage generator for its intended operation. In addition, the feedback voltage of the handpiece, which can be provided, for example, by the piezo-based drive unit, can be used as the electrical operating state variable. For this purpose, the electrical voltage of the piezo-based drive unit can be detected, for example, when the AC voltage generator has been deactivated shortly beforehand. In this case, since the piezo-based drive unit can still contain energy, but the AC voltage generator no longer acts on the piezo-based drive unit, data about the operating state of the handpiece, in particular the piezo-based drive unit, can be determined from the feedback voltage then recorded will.

The advantages and effects given for the method according to the invention naturally also apply equally to the ophthalmic surgical device according to the invention and the system according to the invention and vice versa. Process features can thus also be formulated as device features and vice versa.

Further features of the invention result from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respectively specified combination, but also in other combinations, without the scope of the invention leave. Embodiments of the invention are thus also to be regarded as encompassed and disclosed, which are not explicitly shown and explained in the figures, but which emerge from the explanations explained and can be generated by separate combinations of features. Designs and combinations of features are also to be regarded as disclosed, which therefore do not have all the features of an originally formulated independent claim. In addition, versions and combinations of features, in particular by the above-described versions, are to be regarded as disclosed, which are based on the in the combinations of features set out back references of the claims go beyond or deviate from these.

Figure list

• 1 eine schematische Darstellung eines Ausführungsbeispiels eines ophthalmochirurgischen Systems mit einem Ausführungsbeispiel für eine ophthalmochirurgische Vorrichtung, die ein an einem Steuergerät der ophthalmochirurgischen Vorrichtung angeschlossenes ophthalmochirurgisches Handstück umfasst;
• 2 eine schematische Darstellung einer vereinfachten und reduzierten Blockansicht der ophthalmochirurgischen Vorrichtung gemäß 1;
• 3 eine schematische Diagrammdarstellung eines Spannungs-Zeitdiagramms, in dem mittels eines ersten Graphen eine Versorgungsspannung für einen Wechselspannungsgenerator für einen Betrieb eines spezifischen Handstücks dargestellt ist, und mit einem zweiten Graphen eine Feedback-Spannung für dieses Handstück dargestellt ist;
• 4 eine schematische Schaltbilddarstellung eines Ausschnitts einer elektronischen Schaltung für einen steuerbaren Wechselspannungsgenerator des Steuergeräts gemäß 2, mit einem Spannungssensor zum Erfassen einer elektrischen Feedback-Spannung des am Steuergerät angeschlossenen Handstücks;
• 5 eine schematische Diagrammdarstellung zweier Steuersignale zum Steuern des Erfassens der Feedback-Spannung, bei der die Steuersignale mittels zweier Graphen dargestellt sind;
• 6 eine schematische Diagrammdarstellung wie 5, bei der ein Bereich VI der 5 vergrößert dargestellt ist;
• 7 eine schematische Diagrammdarstellung basierend auf einer Zeitbasis wie 6, bei der mittels eines ersten Graphen ein gleichgerichtetes und gefiltertes Signal abhängig von der Feedback-Spannung und mittels eines zweiten Graphen ein entsprechend integriertes Signal dargestellt ist;
• 8 eine schematische Diagrammdarstellung für eine Restlebensdauer als Alterung eines Handstücks abhängig von der Zeit; und
• 9 eine schematische Diagrammdarstellung basierend auf 8 für eine stufenweise Anpassung der Versorgungsspannung des Wechselspannungsgenerators gemäß 2 abhängig von der Alterung des Handstücks.

Further advantages and features of the invention are explained with reference to the following drawings, in which:

• 1 a schematic representation of an embodiment of an ophthalmic surgical system with an embodiment for an ophthalmic surgical device, which comprises an ophthalmic surgical handpiece connected to a control device of the ophthalmic surgical device;
• 2nd a schematic representation of a simplified and reduced block view of the ophthalmic surgical device according to 1 ;
• 3rd is a schematic diagram of a voltage-time diagram, in which a supply voltage for an AC voltage generator for operating a specific handpiece is shown by means of a first graph and a feedback voltage for this handpiece is shown with a second graph;
• 4th a schematic circuit diagram representation of a section of an electronic circuit for a controllable AC voltage generator of the control unit according to 2nd , with a voltage sensor for detecting an electrical feedback voltage of the handpiece connected to the control unit;
• 5 is a schematic diagram of two control signals for controlling the detection of the feedback voltage, in which the control signals are shown by means of two graphs;
• 6 a schematic diagram like 5 in which an area VI of the 5 is shown enlarged;
• 7 a schematic diagram representation based on a time base like 6 , in which a rectified and filtered signal as a function of the feedback voltage is represented by means of a first graph and a correspondingly integrated signal is represented by means of a second graph;
• 8th a schematic diagram of a remaining life as aging of a handpiece depending on the time; and
• 9 a schematic diagram based on 8th for a gradual adaptation of the supply voltage of the AC voltage generator in accordance with 2nd depending on the aging of the handpiece.

In the figures, the same reference symbols denote the same features and functions.

In 1 is a schematic representation of an ophthalmic microsurgical system or an ophthalmic surgical system 35 for phaco-surgery on a human eye 36 shown. The representation according to 1 symbolically shows some components of the system 35 for the simplified explanation of the general general functioning of the system 35 .

The system 35 has a device unit 53 , which can be, for example, a trolley or the like. In or on the device unit 53 is preferably an operating unit 38 arranged. This control unit 38 may include, for example, a user interface, an input unit, such as a keyboard or the like, and a display unit, such as a monitor or a display. Furthermore is in the device unit 53 preferably a fluidic system 39 arranged, which has a pump and a control unit for controlling the pump and connected components. The fluidic system 39 has an irrigation device 40 with an irrigation branch and an aspiration device 41 with an aspiration branch. The irrigation device 40 assigns a container 42 for rinsing liquid, for example a BSS solution, which is a fluid for irrigation, which is directed to a phaco handpiece. The phaco handpiece is an ophthalmic surgical handpiece 3rd . It is particularly part of the ophthalmic surgical system 35 . The aspiration device 41 is also with the ophthalmic surgical handpiece 3rd connected.

Furthermore, the device unit points 53 especially an ultrasound unit 54 on which is used for oscillation excitation of piezoelectric elements 43 in the ophthalmic surgical handpiece 3rd is formed, through which a hollow needle 14 as a processing needle of the ophthalmic surgical handpiece 3rd is stimulated to oscillate. The piezoelectric elements 43 form a piezo-based drive unit 2nd . The ultrasound unit 54 in the present case comprises at least one control unit 1 with at least one AC voltage generator 4th , a generator control unit 8th and a voltage sensor 7 ( 2nd ).

The device unit 53 also has in particular a control unit 55 on. The control unit 55 can also be used to control a vitrectomy Handpiece 46 , which is particularly part of the ophthalmic surgical system 35 can be trained. The vitrectomy handpiece 46 is preferably also with the fluidic system 39 especially through an aspiration line 47 connected. In addition, another instrument control unit 48 be provided, which is preferably a further available surgical instrument 49 , for example for diathermy, controls. In addition, the system 35 and especially the device unit 53 include further modules and control units as well as systems, which are symbolized by the unit 50 are shown. This also includes other internal units and peripheral devices. The ophthalmic system 35 preferably also has a foot control panel 51 on which with the device unit 53 , in particular with communication devices and control units of the device unit 53 , connected is.

In 1 is also schematically a natural eye lens 52 in the eye 36 shown. This eye lens 52 can through the ophthalmic surgical system 35 , in particular by phacoemulsification.

In an alternative embodiment it can be provided that the ophthalmic surgical system 35 one to the container 42 separate tank 44 ( 1 ) having. In such an embodiment is separate from the irrigation device 40 and separately from the container 42 the cooling fluid, which is provided for cooling the incision, is provided. The Tank 44 can be separated from the handpiece 3rd be arranged and for example via a line, such as a hose connection, with the handpiece 3rd be connected.

In a further embodiment it can be provided that the separate tank 44 in the handpiece 3rd is arranged. It can be non-destructively detachable or non-destructively detachable in the handpiece 3rd be arranged. It can also be provided that in the handpiece 3rd a first separate tank 44 is arranged and external to the handpiece 3rd another separate tank 56 is arranged. This to the handpiece 3rd external additional separate tank 56 can with the first separate tank 44 that in the handpiece 3rd is arranged to be fluidly connected.

2nd shows a schematic block view of a reduced block view of an ophthalmic surgical device 37 of the ophthalmic surgical system 35 according to 1 . The ophthalmic surgical device 37 includes the ophthalmic surgical handpiece 3rd for editing an eye lens 52 of a living being with the piezo-based drive unit 2nd , which in the present case has four piezoelectric elements, not shown, which are arranged mechanically in series with one another and are subjected to a mechanical preload by means of a clamping device, not shown. The piezo-based drive unit thus formed 2nd serves as a mechanical drive for the processing needle 14 of the handpiece 3rd , by means of which the processing of the eye lens 52 can be made.

The drive unit 2nd is trained, the processing needle 14 to excite mechanical vibrations in such a way that a mechanical vibration is generated in a frequency range from approximately 20 kHz to approximately 80 kHz. A vibration amplitude can be approximately 100 µm.

The handpiece 3rd also includes an EEPROM 12 as a data memory for storing handpiece-specific data. In the present case, the handpiece-specific data comprise at least identification data that are relevant for the respective handpiece 3rd are individual.

The ophthalmic handpiece 3rd also includes a communication interface 15 that to the EEPROM 12 is connected and that for establishing a communication link between the EEPROM 12 and a control unit 1 serves.

The ophthalmic surgical device 37 also includes the control unit 1 , which serves the ophthalmic surgical handpiece 3rd to operate in a predetermined manner. The control unit 1 is therefore for that by means of the piezo-based drive unit 2nd drivable ophthalmic surgical handpiece 3rd for editing an eye lens 52 educated. For this purpose it is provided that the control device 1 a supply interface 13 has a communication interface 11 includes. Accordingly, the handpiece also includes 3rd a supply interface 16 that the communication interface 15 includes. The supply interface 13 is via a supply line 18th with the supply interface 16 of the handpiece 3rd releasably connected via a plug connection, not shown. This allows the control unit 1 with different handpieces 3rd get connected.

The control unit 1 has the controllable AC voltage generator 4th on that over electrical wires 19th to the supply interface 13 is connected and there is an AC voltage for the drive unit 2nd provides. A corresponding electrical connection is provided on the handpiece side, so that the drive unit 2nd to the supply lines 19th can be connected. In the present case, the AC voltage has an amplitude that can be set in a range from approximately 20 V to approximately 30 V. The amplitude of the AC voltage is depending on a control signal 6 adjustable for the amplitude.

In order to adjust the amplitude of the alternating voltage, the control device has 1 a power supply 20th on what a supply voltage 17th for the AC voltage generator 4th provides. By means of the control signal 6 for the amplitude can be a value of the supply voltage 17th and consequently also the amplitude of the voltage generated by the AC voltage generator 4th provided AC voltage can be set. By means of another control signal 5 For the frequency, a frequency can be generated by the AC voltage generator 4th provided AC voltage can be set. This serves the handpiece 3rd to be able to operate as far as possible in the range of its mechanical resonance frequency.

To the control signals 5 , 6 To be able to determine, includes the AC voltage generator 4th a voltage sensor 7 as an operating state sensor that is connected to the electrical lines 19th connected. The voltage sensor 7 supplies an electrical voltage as feedback voltage 10th , which represents an electrical operating state variable and which of an operating state of the handpiece 3rd is dependent. To measure the feedback voltage 10th becomes the AC voltage generator 4th temporarily deactivated.

The feedback tension 10th becomes a generator control unit 8th of the control unit 1 fed, which depends on the feedback voltage 10th the control signals 5 , 6 provides. For this purpose the generator control unit 8th designed as an electronic control unit. At the same time, the AC voltage generator 4th by means of the generator control unit 8th be controlled so that it is for the purpose of detecting the feedback voltage 10th is temporarily deactivated. In the present case, the deactivation period is approximately 450 microseconds. In the present case, this period is repeated at a time interval of approximately 10 ms, so that it is the generator control unit 8th enables the actual mechanical resonance frequency of the handpiece 3rd essentially to determine timely and the frequency of the AC voltage generator 4th provided AC voltage by means of the control signal 5 for the frequency as accurately as possible, so that the handpiece 3rd can be operated essentially in its current mechanical resonance frequency.

To the generator control unit 8th is also an evaluation unit 9 of the control unit 1 connected, which is formed before an end of usability for the intended usability of the handpiece 3rd is reached, forecast data for a remaining intended use of the handpiece 3rd until the end of usability at least depending on the value of the at least one control signal 5 , 6 and / or the feedback voltage 10th to determine and, depending on the forecast data, a corresponding statement for informing a user of the handpiece 3rd to provide. In the present case, the corresponding information is a percentage, as is also shown below using 8th is explained. Via a display interface 21st of the control unit 1 that to the evaluation unit 9 is connected, the corresponding indication for an optical and / or acoustic and / or haptic reproduction can be sent to the display interface by means of a suitable one 21st connected display device are output so that an operator can capture this information. The display device is not shown in the figures.

The evaluation unit 9 is in one piece with the generator control unit 8th educated. For this purpose, a program-controlled computer unit is provided, which performs the necessary functions of the evaluation unit 9 and the generator control unit 8th realized. In addition, a hardware circuit can also be provided, as required. According to a first embodiment, a voltage difference between a maximum supply voltage is used to determine the forecast data U17max , which forms a comparison value here and in 3rd with a graph 24th is shown, and a current amplitude of the AC voltage generator 4th provided AC voltage, as with the graph 23 in 3rd represented, determined. Taking into account a reference curve for aging of generic handpieces, the forecast data for a remaining intended use of the handpiece are then 3rd determined until the end of usability. The forecast data contain, for example, forecast information about how many operations the handpiece will perform 3rd can still be used as intended. In addition, the forecast data can also contain, for example, forecast information about the period for which the handpiece is used 3rd can still be used as intended. Furthermore, the forecast data can also provide information regarding sterilizations of the handpiece that can still be carried out 3rd include.

Corresponding information is then determined from the forecast data and is used to inform the user or the surgeon about the remaining usability. The information corresponding to the forecast data can then be used for a suitable display device in order to provide a display that can be detected by the user or the operator. The display may include symbols, text, graphics, and / or the like. The ad can also be done acoustically by a signal tone, a voice output or the like. A haptic display can also be provided, for example a vibration of the handpiece 3rd when it needs to be replaced. The display can, for example, be a bar, the length of which includes a% for the remaining usability. The predicted number of sterilizations that can still be carried out can also be displayed.

Around the reference curve for the evaluation unit 9 To be able to provide, the aging is determined beforehand from a predetermined number of handpieces using statistical evaluation methods.

To the control unit 1 and in particular the generator control unit 8th is also an operating device 22 connected, by means of which the surgeon receives the control signals 5 , 6 can set, depending on a current operation progress or a current operation situation. This gives the surgeon the option of using the control unit 22 for example to set the amplitude of the AC voltage. In addition, it can of course also be provided that by means of the operating device 22 the AC voltage generator 4th can be operated in one cycle to the handpiece 3rd for example to operate in a clock mode. The control unit 22 can be designed as an independent device. But it can also from the control unit 38 be included.

The communication interface 11 and the communication interface 15 are on the supply line 18th coupled with each other by wire. This allows between the control unit 1 and the handpiece 3rd a communication link can also be established. This allows the identification data of the handpiece 3rd from its EEPROM 12 read out and for the generator control unit 8th to provide. For this purpose the generator control unit 8th to the communication interface 11 connected.

There is also the option of the generator control unit 8th specific operating data for the respective handpiece 3rd in its EEPROM 12 save. This allows this data for a respective handpiece 3rd be individual and to control the control unit 1 be used. It can be provided that with the connection of the handpiece 3rd to the control unit 1 the corresponding data from the EEPROM 12 read out and to the generator control unit 8th be transmitted.

The generator control unit 8th can then use the AC voltage generator 4th control accordingly so that a predetermined function of the handpiece 3rd can be reached. When an operation is ended, it can be provided that in the generator control unit 8th existing data regarding the handpiece 3rd again in its EEPROM 12 saved for later use. This allows the handpiece to operate 3rd on a respective control unit 1 be improved.

In addition, the EEPROM includes 12 Data regarding the remaining usability of the handpiece 3rd , in the present case a number of by means of the handpiece 3rd operations still feasible. By connecting the handpiece 3rd to the control unit 1 this data can be read out and displayed. The surgeon thus immediately receives information about how many operations he has with this specific handpiece 3rd can still perform. In addition, he can estimate whether the respective handpiece is still suitable for a planned operation.

It is also provided in the present case that the number of operations that can still be carried out is updated by the generator control unit after each operation is performed 8th corresponding data to the handpiece 3rd transmitted, which is then in the EEPROM 12 get saved.

3rd shows in a schematic diagram representation by means of graphs 23 to 26 and 33 how the aging of a specific handpiece 3rd can impact. An abscissa is time t assigned. An ordinate is an electrical voltage U assigned in volts. With the graph 24th is a value for the maximum supply voltage U17max for the AC voltage generator 4th shown, which is also a comparative value for determining the forecast data in relation to the remaining usability of the handpiece 3rd represents before a usability end is reached. This maximum supply voltage U17max is about 27 V. A graph 25th shows a value for a minimum supply voltage U17min for the AC voltage generator 4th at. In the present case, this voltage is approximately 21 V.

With a graph 33 is that by means of the voltage sensor 7 detected feedback voltage 10th shown. With a graph 26 is the minimum feedback voltage U10min shown, which is about 2.1 V in the present case. A graph 23 sets a value for a time-dependent setting of the supply voltage 17th by means of which the feedback voltage is to be achieved 10th can be kept essentially constant, as is the case with the graph 33 is shown. It should be noted that a course of the graph 23 in 3rd only as an example for a specific handpiece 3rd is shown. The course of the graph 23 can be different for other handpieces. The real one Course of the graph 23 is dependent, among other things, on an overlay of different aging effects. This enables the course of the graph 23 Of course, it can also be linear, logarithmic, exponential or the like depending on the time. Combinations of these can also occur, for example for certain time periods.

Out 3rd is especially based on the graph 23 evident that with increasing time the supply voltage 17th is to be selected correspondingly higher to the specified value U10min through which the feedback tension 10th according to the graph 26 to be able to achieve. The feedback tension 10th corresponds to a deflection amplitude through the processing needle 14 of about 100 µm. It can also be seen that the graph 23 the graph 24th at some point t ₁ crosses. From this point t ₁ can the supply voltage 17th cannot be increased further.

Thus, in the present embodiment, the desired minimum value in the intended operation U10min the feedback voltage by the feedback voltage 10th can be achieved, the supply voltage 17th by means of a control circuit of the control unit 1 regulated. In this embodiment, the control circuit comprises at least the AC voltage generator 4th , the generator control unit 8th , the voltage sensor 7 and the power supply 20th . Due to the aging of the piezo-based drive unit 2nd takes the feedback tension 10th with respect to a predetermined amplitude of the AC voltage with increasing use of the handpiece 3rd from. This is based on the feedback voltage 10th detected. The generator control unit 8th determined from the feedback voltage 10th a value of the control signal 6 for the amplitude of the AC voltage, by means of which the power supply 20th for the corresponding provision of the supply voltage 17th is controlled. Depending on the supply voltage provided 17th provides the AC voltage generator 4th the AC voltage is ready with a corresponding amplitude. The aging of the handpiece 3rd to compensate for the value of the control signal 6 for the amplitude of the AC voltage with increasing use of a specific handpiece 3rd in relation to the given value U10min the minimum feedback voltage larger. Based on the control signal 6 for the amplitude of the alternating voltage or the supply voltage actually set depending on it 17th the forecast data can therefore be determined. Can the value of the supply voltage 17th the handpiece should not be enlarged any further in the control loop described above 3rd then no longer used and against a new handpiece 3rd be replaced. How out 3rd can be seen, the feedback tension decreases 10th for points in time after the point in time t ₁ lie, according to an aging of the handpiece 3rd or its piezo-based drive unit 2nd .

Even if in 3rd continuous adjustment of the supply voltage 17th is shown, it can of course be provided in alternative configurations that, for example, a stepped tracking is provided, as will be explained below using 9 is explained.

4th shows a schematic reduced circuit diagram representation of a section of the AC voltage generator 4th . It can be seen that the AC voltage generator 4th a transformer 27 comprises a center tap with the supply voltage 17th is electrically coupled. At respective winding ends, respective unspecified MOSFETs are connected, which in turn are connected to a driver circuit 28 are connected, by means of which the MOSFETs are operated in push-pull mode. The operation of the MOSFET is dependent on the control signal 5 for the frequency controlled by the generator control unit 8th provided. By adjusting the supply voltage 17th the amplitude of the AC voltage provided can also be set at the center tap. The transformer 27 here has a turn ratio of 1: 1. It is designed as a galvanically isolating transformer in order to be able to provide electrical isolation for reasons of electrical safety. A secondary side of the transformer 27 is about the electrical wires 19th to the supply interface 13 connected. The voltage sensor is also on the secondary side 7 connected to the the feedback voltage 10th provides.

5 shows in a schematic diagram representation two control signals, which in 5 using graphs 29 , 30th are shown. The graph 29 provides a control signal for the AC voltage generator 4th represents by means of which the supply of the AC voltage can be controlled. This is a square-wave signal, which comprises narrow square-wave pulses that occur repeatedly at a time interval of, for example, about 10 ms. In 5 is this period with T ₁ designated. The duration of a respective one of the narrow rectangular pulses is, for example, approximately 450 microseconds. In 5 is this period with T ₃ designated. The AC voltage is provided by the AC voltage generator for this period 4th interrupted. During the remaining time period of approximately 9.55 ms between successive square-wave pulses, the AC voltage generator 4th the AC voltage provided. In 5 is this period with T ₂ designated.

With the second graph 30th in 5 a signal is shown which is the detection of the voltage sensor 7 provided feedback voltage 10th controls. This is also a square-wave signal with narrow square-wave pulses, with a respective one of the square-wave pulses in the present case having a time period of approximately 350 μs. In 5 is this period with M ₄ designated. Each of the periods M ₄ is in the present time within a respective period T ₃ positioned. Here are the rectangular pulses of the graph 30th versus the rectangular pulses of the graph 29 positioned so that the AC voltage generator 4th the provision of the AC voltage has already stopped before the feedback voltage is detected 10th through the voltage sensor 7 he follows. This ensures that with the detected feedback voltage 10th the operating state of the free mechanical vibration of the handpiece 3rd can be grasped in its resonance. 6 shows the temporal position of the rectangular pulses on an enlarged scale in the area VI 5 .

7 shows in a further schematic diagram representation by means of two graphs 31 , 32 how the feedback tension 10th is evaluated. The feedback tension 10th there is also an AC voltage, which is initially rectified. The rectified and filtered signal is with the graph 31 shown. With the graph 32 is shown as the signal 31 is integrated by means of an integrator. The signals 31 and 32 serve the generator control unit 8th the control signals 5 and 6 provides accordingly.

The 9 shows in an alternative embodiment with respect to 3rd a voltage-time diagram in a schematic representation, in which the supply voltage 17th is gradually increased. With a graph 33 is the current feedback voltage detected 10th through the voltage sensor 7 shown. It can be seen that once the feedback tension 10th according to the graph 33 due to the aging of the handpiece 3rd the value of the minimum feedback voltage U10min achieved which by the graph 26 is shown, and then the supply voltage 17th is increased by a predetermined amount or a step (see course of the graph 23 ). It can also be seen that at one point in time t ₁ a voltage increase in the supply voltage 17th is no longer possible because this is the maximum value for the supply voltage U17max according to the graph 24th has already reached. At the latest at the time t ₁ should the user of the handpiece 3rd be advised that the end of the useful life of the handpiece 3rd is imminent and should be replaced as soon as possible. If the handpiece is to be used again 3rd The actual feedback voltage continues to drop until one at a time t ₂ the minimum feedback voltage U10min has reached. The handpiece 3rd should then no longer be used and against a new handpiece 3rd be replaced.

8th is a schematic diagram for aging or a remaining life Q of the handpiece 3rd . According to the diagram 8th is the remaining life Q assigned to the ordinate. The abscissa is time t assigned. Using a graph 34 is a change in the remaining life Q of the handpiece 3rd depending on the time t shown. The remaining life Q corresponds to one with a still available usability of the handpiece 3rd corresponding statement. It can be seen that the graph 34 the ordinate intersects at 100%. At a time t ₂ the remaining life is 0%. At the time t ₁ In the last stage, the remaining service life is still 15%. At this time t ₁ can the supply voltage 17th however, can no longer be enlarged. Shortly after each stage of increasing the value of the supply voltage 17th , especially at the time t ₁ , is the feedback tension 10th greater than the minimum value U10min the feedback tension. The value of the feedback voltage 10th falls according to the graph 33 however, with increasing time. After the last stage of increasing the value of the supply voltage 17th the graph reaches 33 the graph 26 at the time t ₂ . At this time t ₂ is the value of the feedback voltage 10th on the value U10min the minimum feedback voltage dropped. Another increase in the value of the supply voltage 17th is no longer possible or provided here. By counting the stages of increasing the supply voltage 17th as well as evaluating the feedback voltage 10th the forecast data can then be determined. Using the display device, not shown, the remaining service life can be shown as a bar length in percent. The surgeon thus has information available which enables him to determine whether the currently selected handpiece 3rd can still be used for a planned operation. The information can also be displayed here, for example, by displaying the number of possible steps for a voltage increase in the supply voltage 17th respectively.

The exemplary embodiments serve exclusively to explain the invention and are not intended to restrict it.

Reference symbol list

1

Control unit

2nd

piezo-based drive unit

3rd

ophthalmic handpiece

4th

AC generator

5

Control signal for the frequency

6

Control signal for the amplitude

7

Voltage sensor

8th

Generator control unit

9

Evaluation unit

10th

Feedback tension

11

Communication interface

12

EEPROM

13

Supply interface

14

Machining needle

15

Communication interface

16

Supply interface

17th

Supply voltage

18th

supply line

19th

cables

20th

power adapter

21st

Display interface

22

Control unit

23

graph

24th

graph

25th

graph

26

graph

27th

transformer

28

Driver circuit

29

graph

30th

graph

31

graph

32

graph

33

graph

34

graph

35

Ophthalmic surgical system

36

eye

37

Ophthalmic surgical device

38

Control unit

39

Fluidic system

40

Irrigation device

41

Aspiration device

42

container

43

piezoelectric elements

44

separate tank

46

Vitrectomy handpiece

47

Aspiration management

48

Instrument control unit

49

surgical instrument

50

unit

51

Foot control panel

52

natural eye lens

53

Device unit

54

Ultrasound unit

55

Control unit

56

separate tank

Q

Remaining life

T ₁

Period

T ₂

Period

T ₃

Period

M ₄

Period

U

tension

U10min

minimum value of the feedback voltage

U17max

maximum supply voltage

U17min

minimum supply voltage

t

time

t ₁

time

t ₂

time

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102011114584 B3 [0005]
• DE 4008594 A1 [0005]

Claims (10)

Method for controlling an ophthalmic surgical handpiece (3) which can be driven by means of a piezo-based drive unit (2) for machining an eye lens (52), comprising: - applying an alternating voltage to the drive unit (2) which is dependent on a controllable alternating voltage generator (4) at least one control signal (5, 6) for controlling the AC voltage generator (4) is provided, - detecting an electrical operating state variable (10) dependent on an operating state of the handpiece (3) by means of an operating state sensor (7), and - generating a value of the at least one Control signal (5, 6) as a function of the at least one detected electrical operating state variable (10) by means of a generator control unit (8), characterized in that before an end of usability for the intended use of the handpiece (3) is reached, forecast data for a remaining intended use Usability of the handpiece (3) up to usability eiteend at least depending on the value of the at least one control signal (5, 6) and / or the electrical operating state variable (10) and depending on the forecast data, a corresponding statement for informing a user of the handpiece (3) is provided. Procedure according to Claim 1 , characterized in that the corresponding indication is additionally provided as a function of a comparison of the at least one control signal (5, 6) and / or the electrical operating state variable (10) with a predeterminable comparison value (17). Procedure according to Claim 1 or 2nd , characterized in that a predicted number of operations that can be carried out by means of the handpiece (3) and / or a predicted period of time for the intended use is generated as the corresponding information. Method according to one of the preceding claims, characterized in that the control signal is adapted in discrete stages in accordance with an aging progress of the handpiece (3), the forecast data being determined on the basis of a number of the stages currently required. Method according to one of the preceding claims, characterized in that data are transmitted via a communication link between the handpiece (3) and the control device (1). Procedure according to Claim 5 , characterized in that the corresponding information is stored as handpiece-specific data in a data memory (12) of the handpiece (3). Procedure according to Claim 5 or 6 , characterized in that the corresponding information is additionally provided as a function of handpiece-specific data read from the data memory, in particular identification data of the handpiece. Method according to one of the preceding claims, characterized in that the supply voltage of the alternating voltage generator is used as a control signal and / or a feedback voltage of the handpiece (3) is used as the electrical operating state variable (10). Ophthalmic surgical device (37) with: - an ophthalmic surgical handpiece (3) which can be driven by means of a piezo-based drive unit (2) for processing an eye lens (52); and - a control device (1) which can be connected to the ophthalmic surgical handpiece (3) at least during intended operation, the control device (1) having a controllable AC voltage generator (4) which is designed as a function of at least one control signal (5, 6) for Controlling the alternating voltage generator (4) to provide an alternating voltage for the piezo-based drive unit (2), has at least one operating state sensor (7) for detecting an electrical operating state quantity (10) dependent on an operating state of the handpiece (3) and a generator control unit (8) for Providing a value of the at least one control signal (5, 6) as a function of a value of the at least one detected electrical operating state variable (10), characterized by an evaluation unit (9) which is designed before an end of usability for the intended use of the handpiece (3 ) is reached, forecast data for a still remaining to determine the end of the intended use of the handpiece (3) until the end of usability at least depending on the value of the at least one control signal (5, 6) and / or the electrical operating state variable (10) and depending on the forecast data, a corresponding statement for informing a user of the Provide handpiece (3). Ophthalmic surgical system (35) for processing an eye lens (52), with at least: - an irrigation device (6), - an aspiration device (7), and - an ophthalmic surgical device (37), characterized in that the Ophthalmic surgical device (37) according to Claim 9 is trained.

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