Intraoral scanning system using magnetic induction

Abstract

Disclosed is an intra-oral scanning system including: a scanning device including at least a first magnetic induction coil; a replaceable scanning tip including at least a second magnetic induction coil; the scanning tip being removably connected to the scanning device; wherein the at least first and second magnetic induction coils are configured to provide power transfer and/or a communication signal between the scanning device and the scanning tip during operation of the scanning system.

Claims

1. An intra-oral scanning system comprising: a scanning device comprising at least a first magnetic induction coil; a replaceable scanning tip comprising at least a second magnetic induction coil; the scanning tip being removably connected to the scanning device; wherein the at least first and second magnetic induction coils are configured to provide power transfer and/or a communication signal between the scanning device and the scanning tip during operation of the scanning system.

2. The scanning system according to claim 1, wherein the power transfer from the scanning device to the scanning tip comprises supplying an alternating voltage or electrical current in the first magnetic induction coil, thereby inducing an electrical current in the second magnetic induction coil.

3. The scanning system according to claim 1, wherein providing the communication signal between the scanning device and the scanning tip comprises providing a frequency, phase or amplitude modulated alternating voltage or current to either the first or second coil, thereby inducing a modulated signal in the other of the first or second coil, wherein the modulated signal comprises the communication transfer from the scanning device to the scanning tip or from the scanner tip to the scanning device.

4. The scanning system according to claim 3, wherein the scanning system is configured to demodulate the modulated signal.

5. The scanning system according to claim 1, wherein the communication signal is placed in a different frequency band than the power transfer signal.

6. The scanning system according to claim 1, wherein: the scanning device further comprises a third magnetic induction coil; the scanner tip further comprises a fourth magnetic induction coil; wherein the first and second magnetic induction coils are configured to provide the power transfer, and the third and fourth magnetic induction coils are configured to provide the communication transfer.

7. The scanning system according to claim 6, wherein the third and/or fourth communication transfer induction coils are twisted 180 degrees around a symmetrical centre, the third and fourth induction coils thereby comprising two halves in the shape of a figure of 8.

8. The scanning system of claim 1, wherein the scanning-tip further comprises: an optical element located at the distal end of the scanning-tip with a reflective surface inside the scanning-tip such that when the optical element receives light from a white light source located in the scanning device, the scanning tip provides white light to the teeth, wherein the optical element is configured for receiving the white light as back-reflected from the teeth, such that when the optical element receives the white light from teeth, the scanning-tip provides the white light to a first image sensor in the scanning device; and an infrared light source configured to emit infrared light, the infrared light source residing in or on the replaceable scanning-tip, whereby the scanning tip provides the infrared light to the teeth.

9. An intra-oral scanning system comprising: a scanning device; a semi-replaceable scanning tip comprising at least a first magnetic induction coil; an infrared adapter configured to replaceably attach to the scanning tip, the infrared adapter comprising at least a second magnetic induction coil and at least one infrared light source; a disposable or reusable hygiene sheath disposed between the scanning tip and the infrared adapter; wherein the at least first and second magnetic induction coils are configured to provide power transfer and/or a communication signal between the scanning device and the scanning tip during operation of the scanning system.

10. The intra-oral scanning system of claim 9, wherein the infrared adapter is configured to attach to the scanning tip by snapping and/or sliding onto the scanning tip.

11. A replaceable scanning-tip for a scanning device, the scanning-tip being configured for intra-oral scanning of teeth, the scanning-tip comprising: an optical element located at the distal end of the scanning-tip with a reflective surface inside the scanning-tip such that when the optical element receives light from a white light source located in the scanning device, the scanning tip provides white light to the teeth, wherein the optical element is configured for receiving the white light as back-reflected from the teeth, such that when the optical element receives the white light from teeth, the scanning-tip provides the white light to a first image sensor in the scanning device; and an infrared light source configured to emit infrared light, the infrared light source residing in or on the replaceable scanning-tip, whereby the scanning tip provides the infrared light to the teeth.

12. The replaceable scanning tip according to claim 11, further comprising a replaceable infrared adapter, the infrared adapter comprising one or more light guides for guiding the infrared light from the scanning tip to the teeth and/or gingiva.

13. The replaceable scanning tip of claim 12, wherein the light guides of the infrared adapter comprise a core and a cladding material, wherein the reflective index of the core is higher than the reflective index of the cladding, such that the infrared light experiences total internal reflection when passing through the one or more light guides.

14. The replaceable scanning tip of claim 12, wherein the light guides of the infrared adapter comprise one or more mirrors such that the infrared light experiences total internal reflection when passing through the one or more light guides

15. The replaceable scanning tip of claim 12, wherein the scanning tip and/or the infrared adapter further comprises one or more windows between the infrared light source and the one or more light guides.

16. The replaceable scanning tip of claim 15, wherein the one or more windows are made from polymers and/or glass.

17. The replaceable scanning tip of claim 15, wherein the scanning tip comprises a first window placed next to the infrared light source, and the infrared adapter comprises a second window, the first and second windows configured to couple the infrared light from the infrared light source to the one or more light guides.

18. The replaceable scanning tip of claim 17, wherein air gaps between the infrared adapter and the first window are filled with a transparent cladding material.

19. The replaceable scanning tip of claim 11, wherein the infrared adapter is configured to attach to the scanning tip by snapping and/or sliding onto the scanning tip.

20. The replaceable scanning-tip according to claim 11, wherein the optical element is further configured for receiving the infrared light as back-reflected from the teeth, such that when the optical element receives infrared light from the teeth, the scanning-tip provides infrared light to a second image sensor.

21. The replaceable scanning-tip according to claim 20, wherein the second image sensor is identical to the first image sensor.

22. The replaceable scanning-tip according to claim 21, wherein the optical element is configured to reflect the white light such that it passes to a first set of pixels on the first image sensor, and wherein the optical element is configured to reflect the infrared light such that it passes to a second set of pixels on the first image sensor

23. The replaceable scanning-tip according to claim 11, wherein the optical element is a mirror comprising a dielectric coating.

24. The replaceable scanning-tip according to claim 11, the tip further comprising one or more light blockers at the distal end of the scanning-tip, said light blockers being configured to block direct and or indirect stray light.

25. The replaceable scanning-tip according to claim 24, wherein the infrared light source comprises a plurality of infrared light sources located at said light blockers.

26. The replaceable scanning-tip according to claim 24, wherein said light blockers are formed as a protrusion integrated in an arm or arms of the scanning device, the protrusion placed above the infrared light source.

27. The replaceable scanning-tip according to claim 11, wherein the scanning-tip further comprises a recognition-interface linked to an integrated memory located in the scanning-tip, the recognition-interface being configured to be read by a recognition-component located on the scanning device when the scanning-tip is mounted on the scanning device.

28. The replaceable scanning-tip according to claim 11, wherein the scanning-tip further comprises a printed circuit board integrated in the scanning-tip, the printed circuit board being configured to provide electricity from the scanning device to the infrared light source.

29. The replaceable scanning-tip according to claim 11, wherein the replaceable scanning-tip comprises a tubular member comprising a distal end comprising a first optical opening configured to transmit the at least white light to the teeth, and a proximal end comprising a second optical opening configured to transmit the at least white light from the scanning device to the first optical opening, and the proximal end further comprising a mounting interface configured to mount the scanning-tip to the scanning device.

30. The replaceable scanning-tip according to claim 11, wherein the replaceable scanning-tip comprises a shell made of at least two separate parts.

31. A scanning system comprising: the replaceable scanning-tip according to claim 11; and a scanner device configured to replaceably mount the replaceable scanning-tip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0093] The above and/or additional objects, features and advantages of the present invention, will be further described by the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawing(s), wherein:

[0094] FIG. 1 shows a scanning system according to embodiments of the disclosure

[0095] FIG. 2 shows a side view of a scanning tip according to embodiments of the disclosure

[0096] FIG. 3 shows a side view of a first, hard part of the shell of the scanning-tip according to embodiments of the disclosure

[0097] FIG. 4 shows a view of a second, soft part of the shell of the scanning-tip according to embodiments of the disclosure

[0098] FIG. 5 shows a side view of the scanning-tip according to embodiments of the disclosure, showing the first and second part connected according to embodiments of the disclosure

[0099] FIG. 6A shows a mirror frame for holding a mirror according to embodiments of this disclosure

[0100] FIG. 6B shows a PCB part of the scanning-tip including mirror frame and arms for holding infrared LEDs according to embodiments of the disclosure

[0101] FIG. 7A illustrates a first flex pattern of the scanning-tip according to embodiments of the disclosure

[0102] FIG. 7B illustrates a second flex pattern of the scanning-tip according to embodiments of the disclosure

[0103] FIG. 8A-D shows pyramid-shaped light blockers according to embodiments of this disclosure

[0104] FIG. 9 shows an exemplary view of a scanning-tip according to embodiments of this disclosure

[0105] FIG. 10 illustrates an assembly method according to embodiments of the disclosure

[0106] FIG. 11 shows connectors between the scanning-tip and the scanner device according to embodiments of the disclosure

[0107] FIG. 12A shows a scanning device and replaceable scanning tip according to embodiments of the disclosure

[0108] FIG. 12B shows a configuration of magnetic induction coils according to embodiments of the disclosure

[0109] FIG. 13A-C shows various induction coil designs according to embodiments of the disclosure

[0110] FIG. 14A-B shows block diagrams of coil circuitry according to embodiments of the disclosure

[0111] FIG. 15 shows a scanning system according to embodiments of the disclosure

[0112] FIG. 16A-C illustrates light guide designs according to embodiments of the disclosure

[0113] FIG. 17A-D illustrates light coupling designs according to embodiments of the disclosure

[0114] FIG. 18A shows a scanning system according to embodiments of the disclosure

[0115] FIG. 18B illustrates details of a light coupling design according to embodiments of the disclosure

[0116] FIG. 19 illustrates a scanning system according to embodiments of the disclosure

DETAILED DESCRIPTION

[0117] In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

[0118] FIG. 1 shows a scanning system according to an embodiment of this disclosure. In this example, the scanning system 1 is configured for performing intra-oral scanning of at least a portion of a tooth using at least infrared light.

[0119] Further, in this example, the scanning system 1, more particularly the processor 7, is configured to operate in a second processing-mode corresponding to scanning intra-orally with at least infrared light using a scanning-tip 5 therefor.

[0120] This second processing-mode is initiated by mounting the intra-oral tip 5 with a mirror in the distal end that covers the entire optical field-of-view and directs light from the scanner device 2 towards the object to be scanned. The intra-oral tip 5 is shown mounted. This tip is configured for being inserted into the mouth of a patient. Further, in one configuration of the scanning-device 2, the light is selected to trans-illuminate the object to be scanned.

[0121] When the scanning tip 5 is mounted to the scanner device 2, the scanner device 2 reads recognition data 17 in the form of an identification-number 17 of the tip 5 which is stored on an internal memory of the scanning tip 5. The identification-number is forwarded to the controller 8 located on the externally connected computer 11 Based on the scanner-tip identification-number 17, the controller 8 instructs the processor 7 on the scanner device 2 to process a continuous sequence of 2D-images 15 recorded with an infrared-light illumination on the object. To do this, the scanner device 2 is configured to illuminate the object with infrared light into the object, for example into a tooth, and the surrounding gingiva. The scanning tip 5 is configured such that the red light propagates through the gum and tooth material to illuminate the tooth from the inside. The infrared light illumination is controlled by the controller 8 and based on the scanner-tip identification-number 17. In other words, when the controller 8 receives the scanner-tip identification-number 17, the controller 8 additionally instructs the scanner device 2 to emit the infrared light. Further, the controller 8 additionally instructs the scanner device 2 to emit the white light.

[0122] In this manner, a regular sequence of images 15 is recorded with the white-light illumination. However, at a specific point in time, the white light recording is momentarily interrupted to record a single image 20 with infrared illumination. The interruption is based on scan data feedback 21 between the controller 8 and the scanner device 2, the feedback 21 being also based on data 22 from the processor 7. The data 22 from the processor 7 may for example be a 2D image index-number of the infrared image 19. The index-number may be dynamically determined for each image in the sequence of images 15.

[0123] Further, when in the second processing-mode, the processor 7 processes the white light images to derive both data for 3D geometry and data for texture for the surface. Further, the processor 7 processes the single infrared light image to derive data for texture of the internal structure of the object. Finally, the processor correlates data for the texture of the internal structure of the object to the data for the 3D geometry.

[0124] In this example, the scanning application correlates the infrared image 15 to a corresponding position on the 3D-model 13.

[0125] FIG. 2 shows a side view of the scanner tip 5 according to an embodiment of this disclosure. The scanning tip 5 may be either integrated in a scanning device, or preferably be a replaceable scanning-tip for a scanning device. The scanning tip 5 comprises a shell made up of at least two distinct parts, hereafter referred to as a hard part 25 and a soft part 26. The lower inclination 27 of the soft part 26 ensures that the aggregate does not collide with the front teeth when the aggregate is positioned over the largest teeth in scope. The angling of this part of the tip allows for the tip to be moved into the mouth at an angle to allow for the best maneuverability and functionality. The light blocker protrusions/not visible in this view) may also follow this same inclination.

[0126] The front inclination 28 of the soft part ensures that the device can be moved all the way into the mouth cavity and inspect the interproximal area between the two rear molars.

[0127] FIG. 3 shows a side view of the hard part 25 of the shell of the scanning tip 5 according to embodiments of this disclosure.

[0128] FIG. 4 shows a view of the soft part 26 of the shell of the scanning tip 5 according to embodiments of this disclosure. The soft part of the shell comprises protrusions, here illustrated in the shape of mushroom heads 30, although other shapes may equivalently be used.

[0129] FIG. 5 shows a side view of the shell of the scanning tip 5 according to embodiments of this disclosure, after the hard part 25 and the soft part 26 have been attached together. The interaction between the two parts incorporate several features in order to mechanically lock them together and to have surfaces that allow for enough gluing in order to hold them together. The mechanical locking connections are that the front 51 of the soft part 26 overlaps the hard part 25. The hard part has window openings 29, on the inside of which is located a feature or protrusion onto which the soft part 26 is mechanically snapped and fixed in place. A small protrusion or feature overlaps the corner of the window opening to position and mechanically hold the soft part in place. The back end of the soft part 26 may comprise one or more features, here illustrated shaped as mushroom heads 30 placed on each side around the vertical center plane. Although illustrated here as mushroom heads 30 placed symmetrically, other shapes and positioning may equivalently be used. The mushroom heads 30 mechanically snap into complementary holes or windows 29 comprised in the hard part 25. All of the above-mentioned features or protrusions also serve as surfaces for gluing the two parts together.

[0130] FIG. 6A shows the frame 33 for holding the mirror in the tip according to embodiments of this disclosure. The frame for the mirror may comprise grooves incorporated in the sidewalls to allow for the PCB wings to extend out from the PCB heater element part and bend downward at the edge of the frame.

[0131] FIG. 6B shows a flexible printed circuit board (PCB) 34 of the scanning-tip according to embodiments of this disclosure. The flexible PCB 34 comprises two L shaped arms 35 made of flexible PCB. Each of these arms are symmetric and end in a rigid section 36. The rigid section 36 may be made from for example glass-reinforced epoxy laminate material such as FR4. Each arm of the PCB 34 comprises one or more IR LED's 37, here exemplified using 3 LEDs 37. The LEDs 37 point horizontally inwards towards the center plane. Furthermore, the PCB 34 may have an additional wire running along the spine connecting the LED's 37 to the 6th pin in the baronet/pogo pin connection between the scanning-tip and the scanner device.

[0132] FIGS. 7A and 7B illustrate how the soft part 26 may be designed with two different flex patterns in mind. When the scanning-tip is installed on the scanner device, these two flex patterns are both in effect simultaneously.

[0133] The first flex pattern illustrated in FIG. 7A is rotational around the center part of the individual wings coming down at each side of the window opening. In essence, the upper center part of the wing holds more material compared to the sides to allow for this flex pattern to be dominant, but also to allow for the flex PCB to be fixated and run inside the silicone.

[0134] Having this flex pattern enables the center LED to be held in place, so that it is most likely to be situated on the gingiva. When the center LED is optimally placed, the outlying LEDs are less likely to dictate the position of the center LED and therefore they will all be positioned in the best possible way.

[0135] The second flex pattern illustrated in FIG. 7B is a bending of the whole wing from the soft part extremity point at the edge of the window opening. It can be thought of as a cantilever where the whole arm bends out as the light blocker protrusion is being positioned. The flex is predominant above the light blocker to allow for the best possible positioning of the LEDs on the gingiva within the teeth sizes in focus.

[0136] FIGS. 7A and B further shows light blockers 31 according to embodiments of this disclosure. In this embodiment, there is one light blocker 31 in the form of a long protrusion placed above the IR LED's on each side of the scanning-tip. This shape of the light blocker allows the user to randomly position the device within the part of the mouth in focus. To secure that the device is always resting on the bottom part of the teeth, or the top of the gingiva, when the device is positioned, it is designed so that the distance between the two light blockers on either side of the scanning-tip is less than the most narrow teeth in the part of the mouth in focus. In addition to the above-mentioned light blocker concepts, the IR LEDs may also be retracted into the soft part of the shell of the tip, as illustrated with the recesses 32. The protruded/overhanging part of the tip arm over the LEDs additionally functions to add to the light blocking. The three remaining sides around the LEDs may be slanted to allow for maximum light output into the gingiva.

[0137] FIGS. 8A-D shows another shape that may be utilized for the light blockers. In this embodiment, the light blockers are in the shape of a pyramid, which intuitively guides the user to position the device so that the interproximal area between the teeth is right under the center of the window opening. Various exact shapes of the pyramid structure can be envisioned, illustrated with figures A-D. In addition to the above-mentioned light blocker concepts, the IR LEDs may also be retracted into the soft part of the shell of the tip. The protruded/overhanging part of the tip arm over the LEDs additionally functions to add to the light blocking. The three remaining sides around the LEDs may be slanted to allow for maximum light output into the gingiva.

[0138] FIG. 9 shows a view of the scanning-tip 5 according to embodiments of this disclosure. The recessed IR LEDs 37 and the light blocker protrusion 31 is shown. The soft part 26 and the hard part 25 of the shell of the scanning-tip, are also shown.

[0139] FIG. 10 shows a stylized view of the assembly method of the scanning-tip according to embodiments of this disclosure.

[0140] FIG. 11 shows a plurality of connectors between the scanning-tip and the scanner device according to embodiments of the disclosure, here illustrated as pins. The plurality of connectors are located at the proximal end of the scanning-tip.

[0141] In another aspect illustrated in FIG. 12A, the intraoral scanner system comprises an intraoral scanner 2 and a replaceable scanning tip 5 adapted to fit over the distal end of the scanner and to direct probe light from the scanner towards the object to be scanned. The tip is replaceable for hygienic purposes, as it is common practice to remove the tip between treatments and clean and sterilize it before the next treatment. Scanner systems typically ship to end-users with 2 or more tips so the user can use a clean tip on a patient while others are being cleaned. This enables an uninterrupted workflow throughout a typical workday.

[0142] A scanning tip 5 may be designed as an active unit requiring power and data exchange. Physical contacts require protrusion of conductors through the scanner body enclosure for transfer of electrical energy. The cavities introduced around the protrusions are prone to ingress of biological matter and bacteria, making it a challenge to ensure proper cleaning and disinfection of said cavities.

[0143] In these embodiments, the scanner system is designed such that it provides the possibility of exchanging electrical contacts with a magnetic inductive interface 38 which is able to provide both power and/or data exchange between the scanner and the active tip. It does so through magnetically coupled coils in an arrangement that is able to reduce the interference between the data transmission and the power transmission.

[0144] This solution has at least the following three major advantages;

[0145] 1) eliminating the need for electrical contacts makes it possible to hermetically seal both the scanner and tip. This greatly reduces the challenges of cleaning and disinfection.

[0146] 2) improved reliability—eliminating the need for electrical contacts will reduce the risks of mechanical wear. Electrical contacts are some of the points that are most likely to fail in a product. Due to mechanical wear, the contacts performance will eventually degrade to a point where the product seizes to function. In prior art systems, careful mechanical design takes this into account, by attempting to ensure that function seizure is postponed to a point after the expiration of the products service life. Despite this, design tolerances and improper testing methods during development in combination with unintended user actions or unforeseen operating environmental conditions impose risks of premature failure.

[0147] 3) reduce the complexity and size as mechanical contacts require moving parts and demand higher mechanical complexity. Reducing the mechanical complexity allows for a more compact design.

[0148] The solution comprises a power coupling mechanism and/or a communication coupling mechanism.

[0149] The solution may be based on near field magnetic induction and can be realized in different manners.

[0150] Power transmission and communication may be either performed simultaneously or separately during time periods of exclusivity to one or the other mechanism.

[0151] One configuration is displayed in FIG. 12B, showing the front part of the scanner system with the tip 5 mounted on the distal end of the scanner 2.

[0152] The power transfer is based on the physical property of magnetic inductive coupling between adjacent coils of conductors. A supplied alternating electrical current in one coil (hereafter referred to as the TX coil 39) induces a current in the second coil (hereafter referred to as the RX coil 40) due to the magnetic coupling between said coils. The coupling k is dependent on the relative positioning of the coils as well as the geometry of said coils. A non-exhaustive list of various coil configurations are described below:

[0153] A set of circular, oval or rounded-edge rectangular planar or non-planar coils either parallel or placed at an angle relative to each other, with their geometric centers aligned or close thereto (shown in FIG. 12B).

[0154] A set of circular, oval or rounded-edge rectangular planar or non-planar coils formed to conform to a circular shape such as a tube, with their geometric centers aligned or close thereto.

[0155] A set of concentrically helical coils of different diameter placed with their geometric centers aligned or close thereto.

[0156] All configurations could be with or without a ferrite sheet backing to guide the magnetic field.

[0157] The coil pair is operated by application of an alternating voltage or current to the TX coil generating an alternating magnetic field inducing a current in the RX coil. The induced current can be further conditioned in the accessory to provide a stabilized DC voltage supply.

[0158] The system efficiency in terms of power transfer is partly dependent on the losses in the voltage conditioning circuit in the accessory. A difference between the voltage level received by the accessory and the voltage output of the conditioning circuit imposes losses proportional to the loading current of electronics contained in the accessory. Therefore, it is practical to be able to adjust the amplitude of induced current in the RX coil to match the immediate load condition. The accessory may be able to feedback information on the immediate voltage amplitude to the device and the device may adjust the power accordingly by adjustment of either amplitude or frequency of the AC signal applied to the TX coil.

[0159] The communication is additionally based on the physical property of magnetic inductive coupling between adjacent coils of conductors. A supplied alternating electrical current in one coil induces a current in the second coil due to the magnetic coupling between said coils.

[0160] The communication coil on the scanner device side will be referred to as the MST coil 41, and the coil on the tip side will be referred to as the SLV coil 42.

[0161] The operating mode of the coil pair is by application of a frequency, phase or amplitude modulated alternating voltage or current to either the MST coil 39 by the device or the SLV coil 40 by the tip. The applied signal generates an alternating magnetic field inducing an electrical signal current in the receiving coil which may be either the MST or SLV coil depending on the direction of communication (scanning device to scanning tip or scanning tip to scanning device). The induced signal is demodulated according to the employed modulation scheme by the recipient.

[0162] The communication mechanism may be either one of the methods described above or a combination of both.

[0163] The inductive communication mechanism may be based on either a dedicated communications coil or on basis of the same coil set that the power transmission mechanism employs. The solution may thus comprise either:

[0164] 4 coils, where TX and RX are used for power and MST and SLV are used for communication or

[0165] 2 coils, where TX is the same as MST and RX is the same as SLV and vice versa.

[0166] The design of 4 coils is shown in FIG. 13a for the interface on the scanner side. In this case the magnetic field from the TX and RX coils may contribute to a significant noise signal on the MST and SLV coils. A method to eliminate interference from the adjacent alternating magnetic power transmission field, a special communications coil geometry may be utilized as shown in FIG. 14b (only displaying one side of the induction interface). The geometry is such that both communications coils 41 and 42 (not shown) are twisted 180 degrees around a symmetrical center creating two halves resulting in a shape of 8. In such a configuration, placing the communications coil 39 in a uniform, alternating field such as the power transmission field 41 would cause the induced signal in the communications coil to cancel out due to the opposite polarity of the induced current localized to each half of two twisted coils.

[0167] By employing the same twisted geometry on both the MST and SLV coil, an applied communications signal would not cancel out due to the identical localized polarity of each half of both coils. This communication arrangement is displayed in FIG. 13c.

[0168] In the case of only 2 coils, the communication channel may be realized by a frequency, phase or amplitude modulated signal which is placed in another frequency band than the power transfer AC signal.

[0169] The communication may also be implemented by modulation of the frequency of the supplied power transfer AC signal (by the device) and load modulation from the receiving side.

[0170] The coils can be placed in different locations of the scanning system. In the image in FIG. 12B, possible placements are shown for a set of circular planar coils placed parallel to each other. The illustration is based on the 4-coil solution.

[0171] Another implementation comprises concentrically helical coils, where the coils are two solenoids. One solenoid being part of the tip, while the other solenoid is running inside the first one and being part of the front tube assembly.

[0172] For any chosen solution, the power transmitting coil may be connected to one or more capacitors in either series or parallel or a combination hereof, constituting what shall hereafter be referred to as a coil assembly. The capacitance along with the inductance of the coil determines the resonant frequency of the coil assembly.

[0173] The power transfer coil may be driven by either a half or full bridge at a frequency above or below the resonant frequency of the coil assembly. The power transfer between the coil assemblies increase as the frequency of the applied AC signal approaches the resonant frequency of the coil pair. Therefore, it is possible to adjust the power transfer to match the requirement of the receiving devices by modifying the frequency of operation.

[0174] Another means of adjusting the power transfer is by changing the amplitude of the AC signal supplied to the TX coil.

[0175] On the receiving side of the power transfer, the induced current may be rectified either passively through a diode bridge or actively though transistor full bridge. The voltage conditioning may be done either via a switched mode power converter or an LDO.

[0176] An LDO solution is preferred for its smaller solution size and we will handle the E×I losses by means of power transfer governance using the communications mechanism. To reduce the voltage overhead, the key difference between Qi and the 3S derivative is thus the addition of a dedicated communications physical layer for the power arbitration. A block diagram of the transmitter coil excitations circuit can be seen in FIG. 14a.

[0177] The communication may be based on UART. Standard UART implementations consist of dedicated RX and TX lines, but can be implemented in loop-back mode requiring only a single shared physical medium. Limiting the protocol to loopback requires that whoever is transmitting ignores the immediately looped back echo, and the implementation will have a dedicated master to initiate all communications to avoid collisions.

[0178] Pulse duration (t_os) is set at 1.25 times the period of the carrier wave so the oneshot is continuously retriggered by the carrier wave before its pulse duration expires. When triggered, the one-shot output indicates a logical 1.

[0179] Only when the carrier wave has not retriggered the one-shot within the pulse duration period will the one-shot output stabilize to indicate a logical 0. The logical output states may also be inverse to the presence of carrier wave.

[0180] FIG. 14b, shows an implementation on the device side, where the processor on the mainboard of the scanner generates the logical signaling. On the receiving side, a stand-alone uController provides this functionality. Other than that, the solutions share the same features.

[0181] The communication may be based on an On-Off keyed carrier wave. Demodulation requires an envelope tracking circuitry to decode logical levels from the On-Off keyed carrier wave. A one-shot retriggerable monostable multivibrator such as SN74LVC1G123 may be used for the purpose. The pulse duration means that there will be a delay (t_delay) from when the carrier wave disappears until the data line goes low. Using a 1 MHz carrier wave with a corresponding period of 1 μs, a worst-case delay on the output of the one-shot is 1.25 μs. UART accuracy requirement of 1.5%, imposes a minimum carrier wave burst length duration of 1.25e-6/0.015=83 μs, corresponding to a baud rate of 12 kHz.

[0182] In this implementation,t he use of a uController on the receiving side may be used.

[0183] Another option is to use an NFC tag (RFID) and reader solution to act as a transparent I2C bridge for communication between scanner and tip. In this case the communication would be for example 13.56 MHz amplitude shift keying as is the standard for NFC. The device would host the reader and the accessory would host the tag. For this solution the NXP NTAGS family of tags are under consideration. The area consumption on the accessory side would be modest, but significant on the device side. This would imply a data transmission rate p in the 10-100 kbit/s range.

[0184] This option is based on the 1-wire protocol where the device acts as host and a MSP430 is placed in the receiving side. An MSP430 may act as a 1-wire slave as described in this (TIDUAL9A—June 2016—Revised July 2016 Submit Documentation Feedback Copyright © 2016, Texas Instruments Incorporated Memory Emulation Using 1-Wire® Communication Protocol) application note. The MSP430 would handle further communication with any additional hardware in the tip through downstream I2C slaves and also provide GPIO's for multiplexing potential LEDs so the need for a dedicated chip for that purpose would be eliminated. This solution is a little laborious in development but physically small once implemented. Alternatively, the receiving side could host a 1-Wire-to-I2C Master Bridge such as the Maxim DS28E17. This solution is less adaptive on the accessory side and may impose difficulties in maintaining the 1-Wire timing. DS2482X-100+T is alt.

[0185] Alternatively, the communication may also be implemented by modulating IR, UV or visible light from either the device to the tip, tip to device or both. The physical implementation is by LEDs on the transmitting side and optical sensors on the receiving side. The device and accessory may then encompass for communication either a LED, optical sensor or both depending on the mode of communication implemented. It is also possible to use a Bluetooth System-on-Chip such as the DA14531 from Dialog Semiconductor. The antenna could then be implemented as shown in FIG. 13c. An advantage of this solution is the high data rate which would enable the use of external cameras in the tip and other high data rate features.

[0186] In another example displayed in FIG. 15, show a scanning system 1 with a scanning device 2 configured with a manufacturer-detachable-scanning tip 43 mounted to the scanner body in such a way that during normal operation of the scanner, the manufacturer-detachable scanning tip is practically stationary situated over the distal part of the scanner, hence extending the scanner body into a front assembly containing essential optical elements. The term manufacturer-detachable is used synonymously in this disclosure with the term semi-replaceable. This results in a semi-integrated scanning head providing specific functionality to the scanning device. The scan head may be detached from the main body 2 and replaced with another scan head by a technical skilled person following a specific operational procedure. During everyday operation the scanner-head 43 is however considered to be permanently secured and sealed during operation of the scanner. The scan head is configured to couple with a hygiene sheath 44 fitting tightly at least around the scan head creating a microbial barrier, such that only the hygiene sheath 44 needs to be sterilized or replaced in-between different patients. Such a configuration enables the scan-head to only require medium level cleaning with proper wipes.

[0187] A reusable mechanical seal 45 between the scan head and the scanner body 2 ensures that the microbial barrier can be re-established successfully after the scan head has been replaced there by eliminating the need for any disinfection of the scanner front tube.

[0188] The tip interface of the scanning device is configured with a service connector interface 46 and proximity sensors (for example hall sensors) 47 to enable detection of which sleeve type is used over the scanner when the scan head is mounted. The service connector interface is configured to couple with the connectors on the Printed Circuit Board (PCB) 48 located inside the scan head.

[0189] The scan head comprises an optical element 49 to direct probe light from the scanner body towards the object to be scanned along with an optically transparent window 50 or a prism element for sealing the inside of the scan head from coming in contact with the outside environment while not effecting the probe light of the scanner. This secures against any contamination of the interior of the scan head and the front part of the main scanner body.

[0190] In one configuration shown in FIG. 15, the scan head 43 is configured with a mirror 49, a transparent window (for example sapphire glass and a quarter wave plate) 50 configured to transmit the probe light from- and to the scanner and a flexible PCB 48 with a dedicated heating element for heating (ITO, resistive heater, or an inductive heater) the window in the scan head. Additionally, IR light sources 37 may be attached to the PCB. The PCB may also contain a multiplexer for individual IR led control. These IR LEDs 37 may be located in two arrays of 3 IR LEDs located on each side of the scan head 43.

[0191] The scan head 43 is configured to couple with a multiuse hygiene sheath 44 for standard scanning, however the upon identification of an additional IR adapter 51, which is configured to fit outside of the hygiene sheath over the scan head, the scanner identifies the presence of the IR adapter and instructs the processor to enable a dedicated IR scan mode. Such identification could be by recognizing part of the IR adapter with in the FOW of the scanner, thereby instructing the processor to initiate the dedicated scanning mode.

[0192] In some embodiments, the IR adapter 51 shown in FIG. 15 is constructed to passively direct IR light from the scanner head 43 and into the teeth and/or the gingiva to provide an IR transillumination examination of a patient's teeth. The IR adapter is configured to guide the light from the LEDs trough the structure. This implies that there will be a coupling of light from the scan-head 43 to the passive IR adapter 51 part. This coupling could happen through the hygiene sleeve 44. Some design considerations for such a solution include but are not limited to:

[0193] The loss of light should be as small as possible, because losses mean that the LED(s) would have to emit more optical power thus using more electric power. In some embodiments, the scanning device may be wireless, hence powered by one or more batteries. In this case, it is especially important to conserve the power usage to extend the usable scanning time before having to recharge or change batteries.

[0194] The total electric power which can be used by the scanner is limited. LEDs emit heat too and the outer surfaces of the tip should not reach temperatures above 41° C., due to safety regulations and patient comfort.

[0195] The light exits the IR adapter device such that the whole field of view of the scanner is illuminated well. The IR adapter should be made such that it can withstand frequent sterilization cycles, such as autoclave or high-level disinfection in between use.

[0196] The IR adapter outer surface should preferably be smooth and not feature cavities on the outside. The IR adapter should be made from biocompatible materials.

[0197] The shell of the IR adapter 51 may consist of one machined or molded part. Alternatively, the IR adapter may be assembled or manufactured from two or more injection mold shots or machined parts with different softness. The durometer shore hardness value of the softer material used could be A40-A80. This makes the material smooth and pleasant for the patient when the IR adapter is placed in the patient's mouth during scanning. The IR adapter 51 could also comprise one or more additional rigid parts such as a frame stabilizing the construction, directing the light and configured to snap to the shell for attachment.

[0198] As for the choice of LEDs 37, the following criteria should be considered: Efficiency of electrical to optical power transformation, geometrical emission profile and how well it allows coupling to a light guide, size and heat formation.

[0199] The IR adapter 51 may comprise two flexible wings allowing the device to fit various oral cavities and teeth sizes.

[0200] The part of the IR adapter 51 coupling to the scanner-head may have incorporated grooves and interaction surfaces at the side of the shell to mechanically guide and ensure correct attachment between the IR adapter 51 and the rest of the tip assembly, i.e. scan-head 43 and hygiene sheath 44.

[0201] In some embodiments, the IR adapter 51 is made to guide the light from the LEDs through the structure.

[0202] As illustrated in FIG. 16a, in some embodiments the light guides, or light pipes, or optical fibers, or waveguides 52, may be based on the principal of total internal reflection and feature a core 53 and a cladding material 54, where the refractive index of the core is higher than the refractive index of the cladding. Both materials should at least be optically transparent for the respective wavelength emitted by LEDs 37, typically IR light at 850 nm, but wavelengths from 750 nm to 950 nm could be possible, and even longer wave-lengths can be used if desired.

[0203] In other embodiments as shown in FIG. 16b, the light guides may be based on mirrors 55 reflecting light from a reflective surface, such as metal mirrors (e.g. gold), mirrors based on total internal reflection, or dielectric mirrors made from thin layers of dielectric materials. The main performance criterium in this context is high reflection.

[0204] Due to losses at the bends/mirrors a solution with only one bend may be beneficial. Light guide losses can be high for bended light guides, especially if the index contrast between cladding and core is small and the bending radius is high. Thus, mirrors are often used for reflection light instead. Such mirrors can be based in the principles above, where mirrors based on total internal reflection are not very efficient if the angle is high and the index contrast low.

[0205] In the scanner configuration shown in FIG. 15 light must be coupled from the LED to the light guide. If the flexible part is not separated from the scan tip, only one coupling is necessary. However, if the parts are separated, for example by a hygiene barrier a second coupling is necessary. In this context, it is possible to separate the parts between the LED and the light guide. In such a case, windows 56 may be introduced between the light guide and LED(s) as illustrated in FIG. 16c. In this case, coupling will in general be more efficient if the distances and thicknesses are small and if refractive index differences are small in order to minimize loss due to reflections from the window surface. The latter can be achieved by filling air gaps with transparent material 57.

[0206] The windows 56 can also be formed as lenses in order to make the coupling more efficient. Such windows/lenses can be made from polymers or from glass. The separation between the tip part and the part touching the patient can also be made such that the light is coupled from the LED 37 to a first light guide, and from the first light guide to a second light guide in the outer part after-wards. In such a second coupling, the gap between the two guides is critical: The smaller the gap is, the higher the coupling efficiency. The alignment of the two light guides in the vertical direction is also very critical for the coupling losses. In addition, the coupling efficiency can be improved by having the second light guides with a different shape than the first light guides.

[0207] FIG. 17A-D illustrate different improved light coupling designs. Better coupling efficiency can be achieved if the second core is larger, FIG. 17A. In addition, the shape of the second light guide can be tapered as sketched in FIG. 17b. Such a shape can be beneficial, as the light shall be spread within the light guide to achieve illumination of a larger volume in one of the directions (i.e. where multiple LEDs are used).

[0208] The coupling efficiency between two light guides can be improved be introducing a focusing element, such as a lens. Such a lens could be formed separately next to a window, or as the window between the two light guides, FIG. 17c, or as the out shape of the light guide, FIG. 17d. The coupling from the LED 37 to a light guide 52 is generally more efficient the closer the LED is placed to the light guide. Alignment in the lateral directions is critical and can be improved by a larger light guide core compared to the size of the LED. In addition, a tapered light guide can be used to improve coupling efficiency and to change the shape and size of the light guide.

[0209] The wave guides can either be built as individual constructions projecting light from individual LEDs, but they can also be built collectively transporting light from one or more LEDs carrying light to individual exit points.

[0210] Illustrated in FIG. 18A is another embodiment of the scanning system, where the scan-head 43 comprises IR light sources 37 in the distal end and is connected to the scanner 2. The IR light sources are protected by a window 56. The system is configured to couple with a multi-use hygiene barrier sheath 44. The hygiene sheath 44 additionally comprises a coupling window region 56 allowing IR light to be transmitted through the sheath. Additionally, an IR adapter 51 is configured to fit over the hygiene sheath when mounted on the scanner, in order to couple IR light from the scan-head into light guides 52 transporting the illumination to the wing region where the IR light exits the structure.

[0211] The details of a possible coupling arrangement can be seen in FIG. 18B.

[0212] A solution where the light sources are placed in the rear of the scanner-head 43 can be beneficial, because it allows to keep the mechanical dimensions of the distal end smaller, which is an advantage when scanning inside the oral cavity. In addition, the rear of the scan-head 43 may allow to use more space for the light sources and e.g. larger and/or higher power LEDs or lasers.

[0213] Light from the light source may be coupled to a tapered light guide. In these embodiments, a sheath window 57 is placed as part of the hygiene barrier sheath 44 or as a separate unit, which then allows the placing of a single-use transparent sheath on top. The light guide 52 is bended to guide the light down to the bottom end of the tip where it exits the tip. Losses can be high at the window due to coupling losses and reflections. Coupling losses can be minimized by precise control of the two light guides' positions with respect to each other. The window can be formed as a lens and the ends of the light guides can be formed as lenses. It can be beneficial to have two lens elements: One to collimate the light and one to focus the light.

[0214] In another configuration shown in FIG. 19, the scan head 43 is configured with a mirror 49, a transparent window (sapphire glass and quarter wave plate) 50 configured to transmit the probe light from- and to the scanner and a PCB 48 with a dedicated heating element for heating (ITO, resistive heater, or an inductive heater) the window in the scan head. Additionally, an inductive interface 38 is placed behind the optical element 49 on the scan head and also inside the IR adapter 51. The IR adapter 51 may contain one or more infrared light sources, such as two arrays of three IR LEDs 37 located on each side. The scan head 43 may also contain a multiplexer for individual IR led control. These IR LEDs 37 may be located in two arrays of three IR LEDs 37 in each of the wings. The induction interface 38 is configured to transmit both power for powering the IR LEDs 37 and data transmission for controlling the illumination. The IR adapter 51 is configured to fit over the distal end of the scan-head upon the placement of a hygiene sheath 44. In FIG. 19 the hygiene sheath illustrated is a single use sleeve, but multi-use sleeves or sheaths may also be employed.

[0215] The manufacturer-detachable scan tip 43 may provide several advantages over the easy on-the-fly detachable scan tip 5. It is designed for a simple hygiene barrier sheath. This reduces the complexity of the part of the scanner (i.e. Barrier sheath) which needs disinfection between patient. All optical elements as well as PCB heating elements and electrical connectors have been integrated behind a microbial barrier which ensures that these will not have to be designed for either manual cleaning/high level disinfection solutions or sterilizing in autoclave.

[0216] The fact that the optical element for directing the probe light toward the objects is protected inside the scan head 43 leads to longer lifetime and less decay of the optical element, thereby less need to perform frequent re-calibration adjustments when in operation or color corrections depending on the attached mirror in the tip 5. A scanning system adapted to the scan head 43 solution system may easily be upgraded to accommodate new functionalities and needs simply by replacing the scan head only. In case a scanner is accidentally dropped during operation, the front part of the scanner is often prone to be damaged causing the scanner device not to function properly. This type of damage often requires comprehensive repair at a dedicated technical facility. The disclosed scan head solution offers a way to absorb such impact energy and being easily replaceable afterwards. This makes repair of the scanner much faster with less inconvenience for the user as it can be carried out at the location of the user by a technical skilled person.

[0217] As the optical element for directing probe light towards the object to be scanned is confined with in the scan head 43 and not in a tip sleeve 5 no frequent color calibrations are needed as compared to an open tip containing an optical element.

[0218] In device claims enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.

[0219] Although the disclosure above has been described with respect to a replaceable scanning-tip for an intraoral scanner device, the principles therein may equally be employed in a scanner device with an integrated tip. For example, the principles of the dielectric coating, the materials of the tip, the construction and placement of the lightblocker protrusions, the placement of the IR LED's etc. may equally be provided in a scanner device with an integrated tip.

[0220] Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be utilized, and structural and functional modifications may be made without departing from the scope of the present invention.

[0221] A claim may refer to any of the preceding claims, and “any” is understood to mean “any one or more” of the preceding claims.

[0222] The term “obtaining” as used in this specification may refer to physically acquiring for example medical images using a medical imaging device, but it may also refer for example to loading into a computer an image or a digital representation previously acquired.

[0223] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0224] The features of the method described above and, in the following, may be implemented in software and carried out on a data processing system or other processing means caused by the execution of computer-executable instructions. The instructions may be program code means loaded in a memory, such as a RAM, from a storage medium or from another computer via a computer network. Alternatively, the described features may be implemented by hardwired circuitry instead of software or in combination with software.