Multiple thermal sensors in a multiple processor environment for temperature control in a drug delivery device

In various embodiments, an ophthalmic injection device may include a dispensing chamber, a first thermal sensor coupled to the dispensing chamber, a temperature control layer coupled to the dispensing chamber, a second thermal sensor coupled to the dispensing chamber, and a first processing device. The first processing device may be configured to receive temperature information from the first thermal sensor and the second thermal sensor and control the temperature control layer using the received temperature information. In some embodiments, the first processing device may receive temperature information directly from the second thermal sensor (e.g., in analog form) and may compare the temperature information from the first thermal sensor (e.g., received from the second processing device in digital form) and the second thermal sensor to detect temperature offsets between the two sensors.

FIELD OF THE INVENTION

The present invention generally pertains to temperature control devices. More particularly, but not by way of limitation, the present invention pertains to temperature control devices for ophthalmic injections.

DESCRIPTION OF THE RELATED ART

Many diseases of the eye can be treated by injecting a drug into an eye. Injecting a drug into the eye may require control of both the volume and the temperature of the drug to avoid complications. For example, volume control may be important to avoid excessive pressure build-up in the eye. In addition, temperature of the drug may be adjusted to control, for example, a form of the drug (e.g., heated to a liquid for insertion) and/or rate of absorption of the drug into the eye.

SUMMARY OF THE INVENTION

In various embodiments, an ophthalmic injection device may include a dispensing chamber, a first thermal sensor coupled to the dispensing chamber, a temperature control layer coupled to the dispensing chamber, a second thermal sensor coupled to the dispensing chamber, and a first processing device. The first processing device may be configured to receive temperature information from the first and second thermal sensors and control the temperature control layer using the received temperature information.

In some embodiments, the ophthalmic injection device may include a second processing device coupled to the first thermal sensor. The second processing device may be configured to send temperature information from the first thermal sensor (e.g., in digital form) to the first processing device (which may be located, for example, in the dispensing assembly of the ophthalmic injection device). In some embodiments, the first processing device may receive temperature information directly from the second thermal sensor (e.g., in analog form) and may compare the temperature information from the first thermal sensor (received from the first processing device) and the second thermal sensor to detect temperature offsets between the two sensors.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Incorporation by Reference

U.S. Patent Application Publication entitled “Dispensing Assembly For Ophthalmic Injection Device,” Publication No. 20070270744, Ser. No. 11/832,364, by Bruno Dacquay, Cesario Dos Santos, James Foster, Casey Lind, Raffi Pinedjian, and Robert Sanchez filed Aug. 1, 2007 is hereby incorporated by reference in its entirety as though fully and completely set forth herein.

FIG. 1illustrates a block diagram of an ophthalmic injection device100including a dispensing assembly111coupled to a tip segment105. In some embodiments, the tip segment105may include a dispensing chamber103coupled to a thermal feedback layer109and a temperature control layer107. The thermal feedback layer109may include one or more thermal sensors (e.g., thermal sensors115and117) that provide temperature information to a processing device119(which may be located in the dispensing assembly111or the tip segment105). In some embodiments, the thermal sensors may include a thermistor, a thermocouple, etc. and the temperature information may include, for example, a temperature, a temperature gradient, or a change in voltage, current, resistance, etc. that is indicative of a temperature, change in temperature (e.g., a change in resistance on a thermistor), etc. “Dispensing assembly111” is used herein to generally refer to the dispensing assembly of the ophthalmic injection device100and embodiments of the dispensing assembly are denoted herein by letter indicators (e.g., dispensing assembly111ainFIG. 2, dispensing assembly111binFIG. 3, etc).

In some embodiments, first processing device119(and/or other processing devices such as second processing device901shown inFIGS. 9a,9c,10a,10c, and11a) may be programmable to function to control various components of the ophthalmic injection device100. For example, the first processing device119may use temperature information received from the thermal sensors to regulate the temperature control layer107(e.g., first processing device119may interface with the temperature control layer107to activate/deactivate a resistive element121on the temperature control layer107, increase/decrease a heat output of the resistive element121, etc). In some embodiments, the resistive element121of the temperature control layer107may include resistive traces embedded in a flexible insulation layer that convert electrical current into heat or use electrical current to move heat. For example, the resistive traces may include resistive heater traces embedded in Kapton™ and wrapped around the dispensing chamber103to heat the dispensing chamber103and a substance123in the dispensing chamber103. As another example, the resistive element121may include a thermoelectric heat pump with a cool side of the heat pump placed in contact with the dispensing chamber103to cool the dispensing chamber103and a substance123in the dispensing chamber103. Other resistive elements121are also contemplated. Once heated or cooled, the substance123in the chamber103may be injected into an eye131through the needle101.

As seen inFIG. 1, the dispensing chamber103may be substantially cylindrical with a first end face125, a second end face127, and a side face129coupling the first end face125and the second end face127. The thermal feedback layer109and temperature control layer107may be at least partially wrapped around the side face129and/or each other to apply or remove heat through the side face129and detect temperature information associated with a temperature of a substance123in the chamber103. For example, the thermal feedback layer109and temperature control layer107may cover a percentage of the area of the side face129(e.g., >33% covered, >50% covered, >75% covered, etc). In some embodiments, the thermal feedback layer109and temperature control layer107may be wrapped completely around (i.e., 360 degrees around) the side face129and/or may overlap itself.

FIG. 2is an embodiment of an ophthalmic injection device100including a disposable tip segment105and dispensing assembly111a. The tip segment105may include a needle101, a housing215, and a light275. While tip segment105is described throughout as “disposable”, in some embodiments, tip segment105may be used repeatedly. The dispensing assembly111amay include a housing255, a switch270, a lock mechanism265, and a threaded portion260. In some embodiments, tip segment105may be removably coupled to dispensing assembly111a(e.g., through a threaded portion on an interior surface of housing215that screws onto the threaded portion260of dispensing assembly111a). In addition, lock mechanism265may secure tip housing215to dispensing assembly111a. Other coupling mechanisms for the tip segment105and the dispensing assembly111aare also contemplated (e.g., adhesive, snaps, or a unitary housing for the tip segment105and dispensing assembly111a). Needle101may be configured to deliver a substance123from the dispensing chamber103, such as a drug, into an eye131. Needle101may be configured with thermal characteristics that are conducive to drug delivery. For example, needle101may be relatively short (e.g., on the order of several millimeters) in length (for thermal purposes) to facilitate proper delivery of a temperature controlled drug. In some embodiments, switch270may be used to activate the system or to turn on a temperature control layer107.

FIG. 3illustrates another embodiment of dispensing assembly111b. Dispensing assembly111bmay include a button308, a display320, and a housing330. Disposable tip segment105may attach to end340of dispensing assembly111b. In some embodiments, button308may activate a temperature control layer107or initiate actuation of a plunger.

FIG. 4illustrates a cross section view of an embodiment of dispensing assembly111c. As seen inFIG. 4, power source505, interface517, actuator515, and actuator shaft510may be located in housing255. The top part of housing255may have a threaded portion260. Lock mechanism265, switch270, button308, and indicators306,307may all be located on housing255. Power source505may provide power to tip segment105connected to dispensing assembly111c. For example, power source505may provide power to a temperature control layer107and/or thermal feedback layer109located in the tip segment105.

In some embodiments, actuator shaft510may be connected to and driven by actuator515. Actuator515may be a stepper motor or other type of motor that is capable of moving actuator shaft510precise distances. In some embodiments, actuator shaft510may be connected via a mechanical linkage to tip segment105that delivers a drug into an eye131. Actuator515may be a stepper motor that may precisely move shaft510to deliver a precise quantity of drug into the eye131. Actuator515may be secured to an interior surface of housing255by, for example, tabs that engage the outer surface of actuator515.

FIG. 5illustrates a cross section view of a disposable tip segment105interfacing with a dispensing assembly111d, according to an embodiment. In the embodiment shown inFIG. 5, tip segment105may include assembly555, temperature control layer107, thermal feedback layer109(with thermal sensors115and117), plunger interface420, plunger415, dispensing chamber housing425, tip segment housing215, needle101, dispensing chamber103, interface530, and tip interface connector453. While thermal feedback layer109is shown under the temperature control layer107, this may be reversed (e.g., with the temperature control layer107under the thermal feedback layer109). In some embodiments, the thermal feedback layer109and the temperature control layer107may be comprised in a single layer. In some embodiments, dispensing chamber housing425may have a recessed portion that receives the temperature control layer107and/or the thermal feedback layer109. Dispensing assembly111dmay include mechanical linkage interface545, actuator shaft510, actuator515, power source505, first processing device119, dispensing assembly housing255, interface535, and dispensing assembly interface connector553.

In some embodiments, assembly555may include a fuse601that is blown when a heat button is activated or according to instructions from a first processing device119or second processing device901after disposable tip segment105is used (e.g., to prevent reuse of disposable tip segment105). For example, as seen inFIGS. 6cand7b, the fuse601may be in parallel with the heating element121(which may not necessarily be include in assembly555). Other configurations of555are also contemplated. For example, assembly555may include a memory device that stores information about the type of disposable tip segment105, dosage information, temperature information, plunger movement information, or any other type of information that identifies a characteristic of disposable tip segment105or a manner in which disposable tip segment105is operated. For example, assembly555may include a hard-wired memory device, like an NAND (Not And electronic logic gate) flash IC (integrated circuit), an RFID (Radio Frequency Identification) tag, a hard-wired wired circuit that can store a representation of data (e.g., a series of fuses and resistors connected in parallel), or other type of device.

In some embodiments, plunger interface420may be located on one end of plunger415in tip segment105. The other end of plunger415may form one end of dispensing chamber103. Plunger415may slide within dispensing chamber103. The outer surface of plunger415may be fluidly sealed to the inner surface of dispensing chamber housing425. Dispensing chamber housing425may surround the dispensing chamber103(both of which may have a cylindrical shape). In some embodiments, needle101may be fluidly coupled to dispensing chamber103. A substance123(such as a drug) contained in dispensing chamber103may pass through needle101and into an eye131. Temperature control layer107may at least partially surround dispensing chamber housing425and may be connected to tip interface connector453through interface530. Temperature control layer107may include a resistive element121configured to heat or cool dispensing chamber housing425and any substance123contained in dispensing chamber103(which may be made of a thermally conductive material such as copper, steel, etc). Other materials are also contemplated.

The components of tip segment105, including dispensing chamber housing425, temperature control layer107, and plunger415may be at least partially enclosed by tip segment housing215. In some embodiments, plunger415may be sealed to the interior surface of dispensing chamber housing425. This seal may prevent contamination of a substance123contained in dispensing chamber103. This seal may be located at any point on plunger415or dispensing chamber housing425.

In some embodiments, first processing device119and actuator515may be connected by an interface to allow first processing device119to control the operation of actuator515. In addition, an interface between power source505and first processing device119may allow first processing device119to control operation of power source505(which may supply power to the first processing device119and/or actuator515). In such a case, first processing device119may control the charging and the discharging of power source505when power source505is a rechargeable battery.

In some embodiments, tip segment105may mate with or be attached to dispensing assembly111. As seen inFIG. 5, plunger interface420may be located on a bottom surface of plunger415that mates with mechanical linkage interface545located near a top surface of dispensing assembly housing255. In addition, tip interface connector453may connect with dispensing assembly interface connector553. When tip segment105is connected to dispensing assembly111in this manner, actuator515and actuator shaft510may drive plunger415toward needle101. A signal may pass between first processing device119and the thermal feedback layer109or temperature control layer107through interface535, dispensing assembly interface connector553, tip interface connector453, and/or interface530.

In operation, when tip segment105is connected to dispensing assembly111, first processing device119may control operation of actuator515. When actuator515is actuated, actuator shaft510may move toward needle101. In turn, mechanical linkage interface545, which may be mated with plunger interface420, may move plunger415toward needle101. A substance123located in dispensing chamber103may then be expelled through needle101.

In some embodiments, first processing device119and/or second processing device901may control the operation of temperature control layer107based on temperature information received from the first and/or second thermal sensors. For example, temperature control layer107may include a heater and first processing device119may control the amount of current that is sent to the heater based on the received temperature information. In some embodiments, the temperature information may indicate an approximate temperature of the dispensing chamber103and the current may be adjusted to increase or decrease the temperature to a desired temperature. For example, as the current level increases, the temperature of a resistive element121in the heater may increase. In some embodiments, the current may be discontinued if the temperature information indicates a desired temperature has been obtained. Temperature control layer107may be in direct thermal contact with dispensing chamber housing425(or, for example, indirectly through thermal feedback layer109). In some embodiments, temperature control layer107may heat and/or cool dispensing chamber housing425. Since dispensing chamber housing425may be at least partially thermally conductive, heating or cooling dispensing chamber housing425may heat or cool a substance123(such as a drug to be delivered into an eye131) located in dispensing chamber103.

In some embodiments, first processing device119may use a feed back loop utilizing information from the thermal sensors to control the operation of temperature control layer107. A control algorithm, such as a proportional integral derivative (PID) algorithm with temperature information used as at least one of the inputs, may be used to control the operation of temperature control layer107. In some embodiments, temperature information may be transferred from thermal sensor115through interface530, tip interface connector453, dispensing assembly interface connector553, and interface535back to first processing device119.

In some embodiments, thermal sensor115may include a resistive device whose resistance varies with temperature for providing temperature information to use in controlling the operation of temperature control layer107. Thermal sensor115may be located on or near dispensing chamber103and/or housing425to measure a temperature of or near dispensing chamber103and/or housing425. In some embodiments, the temperature information detected by the thermal sensor115may correlate to a temperature of the substance123in dispensing chamber103. Therefore, temperature information for the dispensing chamber103and/or housing425may be used to control a temperature control layer107to heat/cool the substance123located in dispensing chamber103. If the thermal characteristics of dispensing chamber housing425and the substance123is known, the temperature of temperature control layer107may be controlled through the temperature control layer107. Powering the resistive element of temperature control layer107for a specified period of time may result in a calculable change in the temperature of the substance123in dispensing chamber103.

FIGS. 6a-6care schematic depictions of three different circuit embodiments.FIG. 6ashows one of many different configurations for temperature control layer107. InFIG. 6a, temperature control layer107is connected to connectors452and455. Power and/or control signals may be provided to temperature control layer107through connectors452and455.FIG. 6bshows one of many different configurations for thermal sensor115. As seen inFIG. 6b, thermal sensor115may be connected to connectors451and454. Signals may be received from thermal sensor115through connectors451and454. Many other configurations of connectors451,452,453,454,455, and456may be implemented. For example, while six connectors are shown, any number of connectors may be implemented. Further, different combinations of circuits may be contained in a tip segment105.

FIGS. 7a-7cillustrate circuit diagrams of an embodiment incorporating an additional thermal sensor (e.g., thermal sensor117). In some embodiments, a feedback sensor (e.g., one or more thermal sensors) and/or a resistive element (e.g., on temperature control layer107) may be coupled to the tip segment105through one or more contacts (e.g., contacts701a,b). In some embodiments, the temperature control layer107and the thermal sensor115may be placed proximate to each other (e.g., may both be on the tip segment105and in thermal communication with each other). Additional thermal sensors (e.g., thermal sensor117) may also be incorporated in the tip segment105and may be communicatively coupled to a processing device (e.g., processing device119or901) controlling the temperature control layer107. In some embodiments, thermal sensors115,117may include 20 k ohm thermistors (other thermistor sizes are also possible (e.g., 5 k ohm, 30 k ohm)). Processing device layout719inFIG. 7aillustrates an embodiment of a processing device layout for a processing device (such as processing device119which may be a PIC12F683 processor). The additional thermal sensor117may add redundancy to the existing thermal sensor115and may provide additional sources of temperature information for use by the processing devices in controlling temperature control layer107. The additional temperature information may be used by the processing devices to identify a faulty thermal sensor and/or other causes of impedence offsets (e.g., accumulated debris on a thermal sensor, an offset beta value, etc). As another example, a thermal sensor that includes a thermocouple with a poor solder joint may have an offset in the voltage between the thermocouple's junctions that may generate inaccurate thermal readings from the thermocouple. The additional thermal sensor117may reduce the effect of any in-series parasitic resistance on a voltage output from a junction of the first thermal sensor115(e.g., a thermistor) and a load resistance (e.g., the temperature control layer107). The additional thermal sensor117may also eliminate single point failures in the thermistor sense circuit of the feedback layer109. In some embodiments, a processing device may receive temperature information from the two or more thermal sensors115/117(e.g., separately as shown inFIG. 7bor may receive information on a respective difference (e.g., through sensed current/voltage from lines M Voltage and P Voltage which may be electrically coupled to the processor) between the two sensor readings as seen inFIG. 7c) and may determine if the temperature information from the thermal sensors115/117are within a predetermined tolerance. In some embodiments, the thermal sensors115/117may be placed in a bridge configuration (e.g., seeFIG. 7c) with two or more resistors (e.g., resistors703a,b). The output voltage of the bridge circuit may indicate a difference in thermal sensor readings. In some embodiments, the resistors703a,bmay be 3000 ohm resistors (in some embodiments, the values of the thermistors used for the thermal sensors115/117may approach 3000 ohms at the desired temperature of operation). Further, using a bridge may minimize effects from stray resistances in contacts by leveraging the larger resistances of the bridge. Other resistance values are also possible. In some embodiments, the predetermined tolerance may be +/−5 degrees Celsius. Other tolerances may also be used. If temperatures derived from the temperature information are not within the predetermined tolerance (e.g., if one temperature is indicated as 10 degrees higher than the other detected temperature), the processing device (such as processing device119or901) may indicate to the user that there is an error (which may indicate the tip segment105needs to be replaced). In some embodiments, the processing device and/or user may terminate a procedure (e.g., if the error is detected during a surgery) until a replacement tip segment or handpiece is located.

FIGS. 8a-8cillustrate configurations for thermally coupling a thermal sensor115or117(such as a thermistor) to a hub809(which may include, for example, a surface of the chamber103or dispensing chamber housing425), according to various embodiments. As seen inFIG. 8b, a thermal sensor115(or thermal sensor117) may be mounted onto a flap815on the same side as the object to whose temperature is being measured. The flap815may be held on one side/corner of the temperature control layer107and may give way (e.g., break away or tear) when the temperature control layer107is adhered to the hub's surface. In some embodiments, the thermal sensor115/117may be part of a thermal feedback layer109that includes sensory traces (e.g., copper, inconel, etc.) in an insulation material. For example, the one or more thermal sensors115/117may be traces insulated by Kapton™ (other insulation materials are also contemplated). In some embodiments, the thermal sensors115/117may be individual elements that are not in a layer configuration. Placing the thermal sensor115/117on the flap815and filling a gap between the thermal sensor115/117and the flap815with thermal glue811(a.k.a., thermal adhesive/thermal paste) and/or thermal grease may decrease an amount of surface area exposed to the colder ambient air within the ophthalmic injection device100. The placement of the thermal sensor115/117and thermal glue811may also eliminate the insulating layer between the thermal sensor115/117and the chamber103to allow the thermal sensor115/117to provide a better approximation of the chamber temperature. In some embodiments, the thermal sensor115/117may be bonded directly to the hot hub809. While a separate adhesive807is shown inFIG. 8bbetween the thermal sensor115/117and the hub809, adhesive807may not be a separate element from thermal glue811(e.g., thermal glue911and/or thermal sensor115/117may extend to the hub809). In some embodiments, adhesive807may be a separate/additional adhesive. In some embodiments, the adhesive807may be an insulating adhesive or may be a thermal adhesive. As seen inFIG. 8a, the thermal sensor115/117may be fitted into a recess813(e.g., a notched recess) in hub809. As seen inFIG. 8c, the thermal sensor115/117may be placed between the insulation of the temperature control layer107and the hub809. Placing the thermal sensor115/117in the recess813as seen inFIG. 8amay prevent the temperature control layer107from lifting and creating hot air pocket805(which may lead to a less accurate temperature reading by the thermal sensor). The temperature control layer107ofFIG. 8amay need alignment between the thermal sensor115/117and the recess813during manufacturing to insure the thermal sensor115/117fits within the recess813.

In some embodiments, the sensor traces for a thermal sensor in the thermal feedback layer109(e.g., thermal sensor115/117) may be made of copper, silver or gold. These materials may have low resistance and may be highly adherent to improve bondability of the thermal feedback layer109in an assembly (which may include the temperature control layer107and chamber103). These materials may also reduce parasitic resistance caused by the sensor traces being smaller in width than the resistive traces on the temperature control layer107. The reduced parasitic resistance may also reduce temperature offsets that may affect temperature information determined using the sensor traces on the thermal feedback layer109. Other materials are also contemplated (e.g., inconel). In some embodiments, the thermal feedback layer109may include copper traces in a layer of Kapton™ and the temperature control layer107may include inconel traces in a layer of Kapton™. If the sensor traces are made of copper, silver, or gold instead of inconel, the thermal feedback layer109may have an improved bondability that may require less adhesive to bond the thermal feedback layer109to the temperature control layer107than if both the thermal feedback layer109and temperature control layer107included inconel traces.

In some embodiments, the thermal feedback layer109and the temperature control layer107may be manufactured as two separate layers that may then be bonded together to form a combined assembly915a(seeFIG. 9c). The combined assembly915amay then be wrapped around the dispensing chamber103or dispensing chamber housing425. For example, the thermal feedback layer109and the temperature control layer107may be bonded to each other (e.g., through a thermal adhesive) and the combined assembly915amay be wrapped around and bonded to the dispensing chamber103. In some embodiments, the thermal feedback layer109and the temperature control layer107may be separately wrapped around the dispensing chamber103or dispensing chamber housing425. For example, the thermal feedback layer109or the temperature control layer107may be wrapped around and bonded to the dispensing chamber103and then the other of the thermal feedback layer109and the temperature control layer107may be wrapped around and bonded to the dispensing chamber103and/or previously wrapped layer. Thermal adhesive, solder, etc., may be used to bond the various layers to each other and/or the chamber103to thermally couple the layers to the chamber103. In some embodiments, integrated circuits (e.g., forming a second processing device901) may also be bonded to one or more of the thermal feedback layer109and the temperature control layer107(e.g., through solder). In some embodiments, the integrated circuits may not require adhesive in addition to the solder.

FIGS. 10a-cillustrate an embodiment with different form factors for the thermal feedback layer109and temperature control layer107of the tip segment105. In some embodiments, the individual form factors of the thermal feedback layer109and/or temperature control layer107may be reduced to increase the flexibility of the layers107/109and/or combined assembly915b. As seen inFIG. 10a, the thermal feedback layer109may include a form factor with a reduced resistive element tab portion1001. In some embodiments, the temperature control layer (seeFIG. 10b) may not include an IC tab portion1003in the temperature control layer form factor. These reduced form factors may increase the flexibility of each layer with respect to the other layers to improve bondability of the layers to each other and to the dispensing chamber and to improve the flexibility of the combined assembly915b(improved flexibility versus if each layer had the same complete form factor).FIG. 10cillustrates an embodiment of combined assembly915bwith the thermal feedback layer109shown in dashed lines. In some embodiments, the reduced form factor layers may be easier to wrap around the chamber103or dispensing chamber housing425separately to form the combined assembly (which may improve manufacturability of the layers). Other form factors and form factor configurations are also contemplated. For example, other areas of the thermal feedback layer109and the temperature control layer107that do not have, for example, circuitry elements, may be removed or reduced. In addition, elements of the layers may be rearranged and non-used areas may be removed or reduced.

FIGS. 11a-billustrate an embodiment with a second processing device901(e.g., located on tip segment105) to receive temperature information from a first thermal sensor115. In some embodiments, the second processing device901may convert signals from the first thermal sensor115(e.g., signals such as a change in voltage, current, resistance, etc. that is indicative of a change in temperature) to a first processing device119(e.g., on dispensing assembly111). In some embodiments, a first thermal sensor115may be monitored by a second processing device901(which may be a PIC10/12 microprocessor) local to the temperature control layer107. The second processing device901may receive signals (e.g., analog signals) from the first thermal sensor115and may analyze/convert these signals before communicating with the first processing device119. For example, the second processing device901may send digital signals with temperature information (e.g., from the first thermal sensor115) to the first processing device119. The first processing device119may also receive other temperature information (e.g., as an analog signal from a second thermal sensor117as discussed above with respect toFIGS. 7a-b). In some embodiments, both signals (from the first and second thermal sensors) may be digital (or both may be analog). The first processing device119may compare the temperature information from the second processing device901and the temperature information received from the second thermal sensor117to determine if there is an offset between the temperatures detected by the thermal sensors (or, for example, between detected voltages indicative of temperature). Using temperature information from two different thermal sensors may allow the first processing device119to detect an in-series parasitic resistance located on the power, ground, or thermal sensor contact lines (e.g., thermistor contact lines) that may cause a discrepancy between the two signals (e.g., the digital signal and the analog signal). The first and/or second processing devices may try to compensate for the discrepancy if the discrepancy is small (such as <5 degrees Celsius) (e.g., by controlling/adjusting the resistive element121of the temperature control layer107using an average of the temperatures indicated by the first and second thermal sensors) or may indicate an error and/or shut down the ophthalmic medical device100.

In some embodiments, the thermal sensors and/or second processing device901may communicate with first processing device119at least in part through connectors/contacts (e.g., between the tip segment105and the dispensing assembly111). Connectors/contacts (e.g., connectors/contacts701a,band903a-f) may be incorporated at least partially in the dispensing assembly interface connector553(other locations are also contemplated).

In some embodiments, first processing device119may be communicatively coupled to a memory1050(which may be an embedded/on-chip memory and/or a memory external to first processing device119). Other locations for the memory are also contemplated (e.g., as an on-chip memory to second processing device901). In some embodiments, the memory may be a static memory and the information on the memory1050may be accessed digitally. The memory may hold information such as number of times the tip segment105has been used, a temperature set point (e.g., a desired temperature to heat the drug to), drug delivery speed, drug density, drug thermal coefficients of expansion, etc. By storing the number of uses on the memory1050, this information may be used to determine whether to allow the tip segment105to function (e.g., the tip segment105may be prevented from functioning if the number of uses exceeds a predetermined threshold (e.g., 1 use)). Using a memory may eliminate the need for a high current circuit/fuse (although, a fuse601may be also be used). Information stored on the memory1050may also be used in the operation of the tip segment105and/or dispensing assembly111(e.g., set-point temperature, expel velocities, volumes and disposable tip identification, etc). In some embodiments, a programming/debugging pin1101may be used to store information onto the second processing device901(e.g., onto an on-chip memory of second processing device901) and/or to program the second processing device901. For example, an external device such as a computer system may couple to the programming/debugging pin1101to interface with the second processing device901(and/or memory accessible to the second processing device901).

FIG. 12illustrates a flowchart of an embodiment of a method for injecting a substance123into an eye131. The method ofFIG. 12includes activating the temperature control layer107to heat or cool the substance123located in the dispensing chamber103. The elements provided in the flowchart are illustrative only. The provided elements may be omitted, additional elements may be added, and/or various elements may be performed in a different order than provided below.

At1205, a connection between a tip segment105and a dispensing assembly111may be recognized. For example, processing device119may send and/or receive signals from the tip segment105through connectors/contacts701a,band/or903a-f. In some embodiments, components of tip segment105(such as processing device901) may send signals to the processing device119when the tip segment105is coupled to the dispensing assembly111.

At1210, the type of tip segment105may be identified. For example, information may be stored on memory1050as to the type (e.g., single use, limited reuse, etc.) of tip segment105and this information may be passed to the processing device119when the tip segment105is coupled to the dispensing assembly111.

At1215, dosage information may be received from the tip segment105. For example, dosage information (e.g., volume, dispense rate, etc.) may be stored on memory1050and be passed to the processing device119when the tip segment105is coupled to the dispensing assembly111.

At1220, a temperature control layer107may be activated to alter a temperature of a substance123contained in the dispensing chamber103. In some embodiments, the temperature control layer107may be charged by an internal power source and/or may be charged by an external charging stand.

At1225, temperature information (e.g., a change in voltage, current, resistance, etc. that is indicative of a change in temperature) may be received from a thermal sensor (such as thermal sensor115and/or117). As another example, temperature information may be received in the form of a voltage or current detected from a bridge that includes the first and second thermal sensor (e.g., seeFIG. 7c).

At1230, the temperature information may be used to control the temperature control layer107. For example, the processing device119may signal temperature control layer107to provide current to the resistive element121until a set temperature is indicated by one or more thermal sensors.

FIG. 13illustrates a flowchart of an embodiment of a method for operating the tip segment105and dispensing assembly111for injecting a substance123into the eye131. The elements provided in the flowchart are illustrative only. The provided elements may be omitted, additional elements may be added, and/or various elements may be performed in a different order than provided below.

At1305, a user may connect the tip segment105to a handpiece (e.g., a reusable handpiece including the dispensing assembly111).

At1310, the tip segment105(e.g., second processing device901on tip segment105) may transmit information to the dispensing assembly111(e.g., to first processing device119). The information may include pack identification (ID) (identifying a package the tip segment105was delivered in), procedural parameters (e.g., temperature set point, drug delivery speed, drug density, drug thermal coefficients of expansion, etc.), and number of prior uses (or, for example, information indicating that the tip segment105has not been used prior).

At1315, the pack ID and additional information may be verified (e.g., by the first processing device119on the dispensing assembly111). If the number of prior uses exceeds a predetermined threshold or if the information received (or not received) indicates a problem (e.g., does not fall within predetermined ranges), the dispensing assembly111(e.g., the first processing device119) may indicate that the tip segment105should not be used. For example, if the ophthalmic injection device100is a limited reuse assembly and information stored in the memory1050indicates the tip segment105has been used more than a predetermined threshold (e.g., 1 time), the first processing device119may transmit a command to the second processing device901to shut down the tip segment105and/or prevent the tip segment's use.

At1320, the tip segment105may transmit temperature information. For example, the second processing device901may monitor a first thermal sensor115and may send information indicative of temperature information received from the first thermal sensor (e.g., in digital form) to first processing device119. Additional temperature information (e.g., from a second thermal sensor) may be transmitted to the first processing device119directly (e.g., in analog form (or digital form)).

At1325, the temperature information from the first thermal sensor115and the second thermal sensor117may be compared to determine if the indicated temperatures are within tolerance of each other (e.g., within +/−0.5 degrees, +/−1 degrees, +/−5 degrees, +/−10 degrees, etc). In some embodiments, the temperature information may be separately compared to predetermined thresholds instead of being compared to each other. Other comparisons are also contemplated. For example, as seen inFIG. 7c, information (e.g., relayed through a detected voltage or current) from a bridge circuit including the first and second thermal sensor may be indicative of a difference between the two sensors.

At1330, the tip segment105may be allowed to heat or cool a substance123in the dispensing chamber103and the temperature information from the first and second thermal sensors may continue to be monitored. If the detected temperatures are not found to be within a tolerance of each other or separately within a predetermined range, the tip assembly105may be instructed not to initiate heating or cooling a substance123in the dispensing chamber103and/or the tip assembly105may discontinue heating or cooling substance123if the heating/cooling process has already started. In some embodiments, an error may be indicated if the detected temperatures are not within a tolerance. If the heating/cooling sequence had started, a use of the tip segment105may be indicated on a memory1050accessible by the second processing device901and/or first processing device119at startup. The indicated use may prevent the tip segment105from being used again in the future.

FIG. 14illustrates an embodiment of coupling the dispensing chamber housing425to an outer support1401. In some embodiments, the outer support1401may be an elastomer support (other materials such as metal may also be used) that is separately coupled inside the tip housing215. The dispensing chamber housing425may include a bell-shaped end1403that secures the end of the dispensing chamber housing425inside the support1401. For example, one end of the dispensing chamber housing425may fit through the outer support while the bell-shaped end1403may hold the dispensing chamber housing425in place (e.g., through a friction fit (or, for example, through adhesive) with the support1401. The dispensing chamber housing425may be coupled inside the support1401using other mechanisms (e.g., adhesives, fasteners, ultrasonic welding, etc).

FIG. 15illustrates another embodiment of the thermal feedback layer1507. In the embodiment shown inFIG. 15, the thermal feedback layer1507may not include a processing tab segment holding second processing device901. For example, the processing device901may be included on the tab portion1505(or may not be included). In some embodiments, the thermal sensors115/117may be placed further apart on the thermal feedback layer1507and two windows1501/1503may be provided (one for each thermal sensor) for the wrap around (seeFIGS. 16a-d). The circular contact portion may include contacts903a-fon one layer to interface with corresponding contacts on the lower dispensing assembly111e(which, as seen inFIG. 16d, may include multiple corresponding contacts). In some embodiments, the lower dispensing assembly111emay include six corresponding interface connectors1653a-f(see example interface connector553and example dispenser assembly components inFIG. 5). Other configurations are also possible (e.g., data from the six connectors may be placed through a single connector interface with the lower dispenser assembly).

FIGS. 16a-dillustrate an example of assembling the thermal feedback layer1507into the dispenser assembly. As seen inFIG. 16a, the tab portion1505of thermal feedback layer1507may be wrapped around the dispensing chamber housing425such that a thermal sensor115/117lines up on alternate sides of the dispensing chamber housing425and windows1501/1503line up with their corresponding thermal sensor115/117such that each thermal sensor115/117protrudes through respective windows1501/1503. In some embodiments, the bottom of the thermal feedback layer1507may be coated with an adhesive. In some embodiments, a backing may be peeled off of the thermal feedback layer1507to expose the adhesive prior to wrapping the thermal feedback layer1507on the dispensing chamber housing425. Other fasteners are also contemplated (e.g., clips, welds, etc). As seen inFIG. 16b, the thermal feedback layer1507may bend along a contour of the support1401. As seen inFIG. 16c, the circular contact portion may also bend to attach to the back of the support1401to align the contacts903a-fwith corresponding connectors1653a-f(which may themselves be contacts) on the dispensing assembly111e. In some embodiments, contacts903a-fmay be electrically connected to various components on the thermal feedback layer1507(e.g., the thermal sensors115/117) through electrical lines embedded/deposited on the thermal feedback layer1507. In some embodiments, electrical signals may travel through the contacts903a-fand connectors1653a-fto allow the dispenser111eto communicate with the components of the thermal feedback layer1507(or other layers such as the temperature control layer107which may also communicate through corresponding contacts (e.g., contacts903e-fshown inFIG. 9b)). As seen inFIG. 16d, the dispensing chamber housing425may be inserted into tip assembly215which may be coupled to the dispensing assembly111e(to mate connectors1653a-fand contacts903a-f). As seen inFIG. 2, in some embodiments, the tip assembly215may be screwed onto the dispensing assembly111e(other attachment mechanisms are also contemplated).

In some embodiments, the tip segment105and/or dispensing assembly111may include one or more processing devices (e.g., first processing device119, second processing device901, etc). In various embodiments, the processing devices may include integrated circuits with power, input, and output pins capable of performing logic functions. For example, first processing device119may be a targeted device controller that performs specific control functions targeted to one or more devices or components, such as temperature control layer107or power source505. In some embodiments, first processing device119may directly control temperature control layer107or may interface with another processing device (such as a temperature control layer controller on the temperature control layer107) to control the basic functionality of the temperature control layer107. While depicted as one component in various FIGs., processing devices (such as first processing device119, second processing device901, etc.) may each be made of many different components or integrated circuits. For example, each processing device may include a single processing device or a plurality of processing devices.

The processing devices may include a microprocessor (e.g., a programmable microprocessor), controller (such as a micro-controller or other special purpose controller), digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, control circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on operational instructions. A memory coupled to and/or embedded in the processing devices may be a single memory device or a plurality of memory devices. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. Note that when the processing devices implement one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory storing the corresponding operational instructions may be embedded within, or external to, the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. The memory1003may store, and the processing devices may execute, operational instructions corresponding to at least some of the elements illustrated and described in association with the figures.

Various modifications may be made to the presented embodiments by a person of ordinary skill in the art. For example, although some of the embodiments are described above in connection with surgical handpieces, it can also be used with other surgical devices utilizing a heater element. Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof.