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(11) | EP 2 674 949 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | PTC device with casing and means for breaking contact in case of failure |
| (57) The invention discloses an electronic device including: an electronic PTC element (5) with a first electrode (51) and a second electrode (52) disposed on the opposite sides thereof; a first terminal (71) and a second terminal (81); a first support mounted (3) to and electrically connected with the first terminal, the first support comprising a first contact part (71) contacting and electrically connected with the first electrode; a second support (4) mounted to and electrically connected with the second terminal, the second support comprising a second contact part (81) contacting and electrically connected with the second electrode; a third elastic support (6) comprising a third contact part (63) contacting with one of the first electrode and the second electrode, wherein the third elastic support is provided so as to push the electronic element out of contact with one of the first support and the second support when the electronic element breaks in a failure state. |
TECHNICAL FIELD
[0001] The present invention relates to an electronic device, in particular, to a positive temperature coefficient (PTC) thermistor device.
BACKGROUND
[0002] Thermistor device has been widely used in current limiting circuit, including motor staring circuit in a refrigeration device such as a refrigerator. After being used for long time, the physical structure of the prior art PTC device may deteriorate, creating abnormal heat inside the device and breaking the PTC element into fragments. Since the fragments may still be connected with the terminal, issues such as arc discharging, overheating, over current, etc. may occur.
[0003] U.S. patent No. 6,172,593 assigned to Murata Manufacturing Co., Ltd. Introduces an electronic device with two spring contact parts and two non-conductive contact parts. During operation period, the four contact parts contact with PTC, and the two spring contact parts are welded to the left and right terminals respectively. On one hand, the material closely contact with PTC (non-conductive contact parts) need to be resistant to high temperature and thus is relative expensive. On the other hand, in the case that PTC is broken without disconnecting current, the fragment of PTC still electrically connected with the terminals, creating arc discharging and over-heating.
[0004] CN patent application CN102347123 filed by Sensata Technologies Massachusetts, Inc. introduces a thermistor device with three elastic support and a pair of insulated offset posts, wherein two elastic support is welded to a terminal and a third elastic support is welded to another terminal. Said pair of offset posts are spaced from the thermistor element. Since the posts do not contact with the PTC element, it does not need expensive material resistant to high-temperature. However, in the case that the thermistor is broken without disconnecting current, the fragment of the thermistor still electrically connected with the terminals, creating arc discharging and overheating.
[0005] Thus, current thermistor device may not be able to reliably eliminate the issues of arc discharging and overheating in a failure broken state.
SUMMARY
[0006] It is an object of the present disclosure to provide an electronic device, in the case that an electronic element such as a thermistor element is broken, the circuit can be securely disconnected, so as to eliminate the issues such as arc discharging and overheating.
[0007] The present disclosure presents an electronic device includes: an electronic element with a first electrode and a second electrode disposed on the opposite sides thereof; a first terminal and a second terminal; a first support mounted to and electrically connected with the first terminal, the first support comprising a first contact part contacting and electrically connected with the first electrode; a second support mounted to and electrically connected with the second terminal, the second support comprising a second contact part contacting and electrically connected with the second electrode; a third elastic support comprising a third contact part contacting with one of the first electrode and the second electrode, wherein the third elastic support is provided so as to push the electronic element out of contact with one of the first support and the second support when the electronic element breaks in a failure state.
[0008] According to the present electronic device, in the case that the electronic element broken, the elastic force of the third elastic support pushes the fragments of the electronic element away so that the fragments do not contact with one of the first support and the second support, disconnecting the electronic element with one of the terminals, disconnecting the circuit and eliminating the issues of arc discharging and overheating.
[0009] The third elastic support may be electrically insulated with said one of the first support and the second support as well as the terminal electrically connected therewith, when the electronic element breaks in a failure state.
[0011] The second support may be a rigid support, and the third contact part contacts with the second electrode at a position close to the second contact part.
[0012] The third elastic support may comprise a first elastic part providing the third contact part and a second elastic part including a forth contact part contacting with the second electrode at a position different from the second contact part and the third contact part.
[0013] The first contact part may be closer to the center of the electronic element than the second contact part and the forth contact part, and the second contact part and the forth contact part may be opposite to each other across the first contact part.
[0014] The second elastic part may apply a second elastic force on the electronic element, the first elastic part may apply a first elastic force on the electronic element, and the second elastic force may be greater than the first elastic force.
[0015] The electronic device may be such that fragments of the electronic element are pushed away from the second support by the first elastic force when the electronic element breaks in a failure state, so that the second support is out of contact with the second electrode.
[0016] In normal status, the first support may apply a force toward the first electrode and the second support may apply a force toward the second electrode due to the first elastic force and the second elastic force, so that the first support keeps close contact with the first electrode and the second support keeps close contact with the second electrode.
[0017] The first elastic part may comprise two elastic forks, the second contact part being positioned between the two forks and spaced therewith.
[0018] An elastic force on the electronic element applied by the second elastic part may be greater than the sum of the elastic force on the electronic element applied by the two forks.
[0019] The second contact part may be spaced from the two forks in a direction crossing a line connecting the second contact part with the forth contact part.
[0021] The first contact part may be positioned at the center of the electronic element, and a line connecting the second contact part and the forth contact part may pass the center of the electronic element.
[0025] The electronic device may further include a forth elastic support with a forth contact part contacting the second electrode at a position different with the second contact part and the third contact part.
[0026] The first contact part may be closer to the center of the electronic element than the second contact part and the forth contact part, and the second contact part and the forth contact part may be opposite to each other across the first contact part.
[0027] The forth elastic part may apply a second elastic force on the electronic element, the third elastic part may apply a first elastic force on the electronic element, and the second elastic force may be greater than the first elastic force.
[0028] The electronic device may be such that fragments of the electronic element are pushed away from the second support by the first elastic force when the electronic element breaks in a failure state, so that the second support is out of contact with the second electrode.
[0029] In normal status, the first support may apply a force toward a first electrode and the second support may apply a force toward a second electrode due to the first elastic force and the second elastic force, so that the first support keeps close contact with the first electrode and the second support keeps close contact with the second electrode.
[0030] The third elastic part may comprise two elastic forks, the second contact part being positioned between the two forks and spaced therewith.
[0031] The elastic force on the electronic element applied by the forth elastic part may be greater than the sum of the elastic force on the electronic element applied by the two forks.
[0032] The second contact part may be spaced from the two forks in a direction crossing a line connecting the second contact part with the forth contact part.
[0034] The first contact part may be positioned at the center of the electronic element, and a line connecting the second contact part and the forth contact part may pass the center of the electronic element.
[0038] The first support may be a rigid support, and the third contact part may contact with the first electrode at a position close to the first contact part.
[0039] The electronic device may further include a fifth support with a fifth contact part contacting the second electrode at a position different with the second contact part.
[0040] The first contact part may be closer to the center of the electronic element than the second contact part and the fifth contact part, and the second contact part and the fifth contact part may be opposite to each other across the first contact part.
[0042] The second support may apply a second elastic force on the electronic element, the fifth support may apply a fifth elastic force on the electronic element, the third elastic support may apply a fist elastic force on the electronic element, and the sum of the second elastic force and the fifth elastic force may be greater than the first elastic force.
[0043] The electronic device may be such that fragments of the electronic element are pushed away from the first support by the first elastic force when the electronic element breaks in a failure state, so that the first support is out of contact with the first electrode.
[0044] In normal status, the first support may apply a force toward a first electrode due to the first elastic force, the second elastic force and the fifth elastic force, so that the first support keeps close contact with the first electrode.
[0045] The third elastic part may comprise two elastic forks, the first contact part being positioned between the two forks and spaced therewith.
[0047] The first contact part may be positioned at the center of the electronic element, and a line connecting the second contact part and the forth contact part may pass the center of the electronic element.
[0052] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.
[0054] Fig. 1 is a perspective view of a PTC thermistor device according to one embodiment of the present invention in an assembled status.
[0057] Fig. 4 is a sectional view cut along I-I in Fig.3, wherein the electronic element is illustrated in a transparent manner.
[0058] Fig. 5 shows the position relationship between the electronic element and the supports in a normal operation status.
[0059] Fig. 6 shows the position relationship between the electronic element and the supports in a failure status.
[0060] Fig. 7 shows a PTC thermistor device according to another embodiment of the present invention.
[0061] Fig. 8 shows a PTC thermistor device according to a further embodiment of the present invention.
[0062] Fig. 9 shows the position relationship between the electronic element and the supports in a failure status of electric device of Fig. 8.
DETAILED DESCRIPTION
First Embodiment
[0063] Fig. 1 is a perspective view of an electronic device 100 such as a PTC thermistor device according to one embodiment of the present invention in an assembled status. Fig. 2 is a perspective view of the PTC thermistor device in an exploded status.
[0064] As shown in Fig. 2, the electronic device 100 includes a cover 1, a base 2, a first terminal 3, a second terminal 4 and an electronic element 5. The electronic element 5 is such as a PTC disc. The electronic element has a first electrode 51 and a second electrode 52 disposed on the opposite sides thereof.
[0065] The electronic device 100 further includes a first support 7 with a first contact part 71 contacting and electrically connecting with the first electrode 51; and a second support 8 with a second contact port 81 contacting and electrically connecting with the second electrode 52. The first support 7 is mounted on the first terminal 3 and electrically connected therewith. The second support 8 is mounted on the second terminal 4 and is electrically connected therewith. Preferably, the first support 7 is integral with the first terminal 3. Preferably, the second support 8 is integral with the second terminal 4. The second support 8 is a rigid support. Preferably, the first support 7 is a rigid support. Alternatively, the first 7 could be an elastic support.
[0066] The electronic device 100 further includes a third elastic support 6. The third support 6 is such as a spring. The third support 6 has a third contact part 63 contacting with the second electrode 52 at a position close to the second contact part 81. Preferably, the third contact part 63 is spaced from the second contact part 81. Alternatively, the third contact part 63 may contact with or overlap with the second contact part 81.
[0067] The third support 6 preferably includes a first elastic part and a second elastic part 62. The first elastic part 61 provides said third contact part 63. The second elastic part 62 includes a forth contact part 64. The forth contact part 64 contacts the second electrode 52 at a position different from the second contact part 81 and the third contact part 63.
[0068] Fig. 3 is a top view of the PTC thermistor device with the cover removed. As shown in Fig.3, the first contact part 71 is closer to the center of the electronic element 5 than the second contact part 81 and the forth contact part 64, and the second contact part 81 and the forth contact part 64 is opposite to each other across the first contact part 71. Preferably, the first contact part 71 is positioned on the center of the electronic element 5 and a line connecting the second contact part 81 and the forth contact part 64 passes the center of the electronic device. In other word, the second contact part 81 and forth contact part 64 is positioned on two radial sides of the first contact part 71. The first contact part 71 abuts the first electrode 51 of the electronic element 5 at a general center position. The second contact part abuts the second electrode 52 of the electronic element 5. The first elastic part 61 applies an elastic force on the electronic element 5 via the third contact part 63. The second elastic part 62 applies an elastic force on the electronic element 5 via the forth contact part 64. Thus, the first support 7 and the second support 8 apply a force toward the electronic element 5 against the elastic force of the first elastic part 61 and the second elastic part 62, so that closer contact may be formed between the first contact part 71 and the first electrode 51, and the second contact part 81 and the second electrode 52. In this way the electronic element 5 forms a more reliable connection with the first terminal 3 and the second terminal 4.
[0069] One skilled in the art understands that the elastic force applied on the electronic element by the second elastic part 61 need to be larger than that applied on the electronic element by the first elastic part 61, so that the first support 7 and the second support 8 can apply a force toward the electronic element 5 to realize a close contact.
[0070] Fig. 5 shows in a normal operation status, the first support 7 (the first contact part 71), the second support 8 (the second contact part 81), the first elastic part 61 (the third contact part 63), the second elastic part 62 (the forth contact part 64) apply a force on the electronic element 5 respectively. The force applied by the first support 7 usually is larger than that applied by the second support 8. In a failure status, the force applied by the first support 7 close to the center of the electronic element 5 increase the possibility that the plane passing the center breaks.
[0071] Fig. 6 shows in a failure status, the electronic element 5 breaks along a plane passing near the center. The elastic force of the first elastic part 61 with the third contact part 63 drives the fragments of the electronic element 5 away from the second contact part 81, separating the fragments from the second contact part 81. That is, the second support 8 is out of contact with the second electrode. Since the second support 8 is a rigid support without any compression, when the first elastic part 61 pushes away the fragments, the second support 8 does not contact with the electronic element 5 anymore. In the failure status, the third elastic support 6 is insulated with the second support 8 and the second terminal 4. For instance, the third elastic support 6 is made of an insulated material. Alternatively, in the case that the third support 6 is conductive, the third support 6 is spaced from the second support 8 and the second terminal 4 or is spaced via insulated material. Thus the electrical connection between the electronic element 5 and the second terminal 4 is cut, the fragments are disconnected from the circuit and the short cut is prevented.
[0072] In a preferred manner, the first elastic part 61 may includes two elastic forks 61a, 61b with two third contact parts 63 contacting the second electrode 52. As shown in Fig. 4, the second contact part 81 is positioned between the two third contact parts 63 and spaced therewith. In a direction crossing a line connecting the second contact part 81 and the forth contact part 64, the second contact part 81 and the third contact parts 63 are spaced. Preferably, in a direction generally perpendicular to a line connecting the second contact part 81 and the forth contact part 64, the second contact part 81 is spaced from the third contact parts 63. In a PTC device in a refrigerant starter, the spaced distance between the second contact part 81 and the third contact part 63 usually less than about 2mm but is not limited to that value. The elastic force applied on the electronic element 5 by the second elastic part 62 is larger than the sum of the that applied by the two elastic forks 61a, 61b. In a normal operation status, the first support 7 and the second support 8 apply force toward the electronic element 6 to realize close contact. In a failure status, the two elastic forks 61a, 61b push the fragments of the electronic element 5 way from the second contact part 81, so that the second support 8 is out of contact with the second electrode 52 and the fragments is disconnected from the circuit.
[0073] One skilled in the art understands that the firs elastic part 61 is not limited to including two elastic forks 61a, 61b, but could includes other numbers of forks, as long as the balance of the electronic device 100 can be maintained and the fragments can be pushed away from the second contact part in a failure status.
Second Embodiment
[0074] Fig. 7 shows a PTC thermistor device 100' according to the second embodiment of the present invention. Except for the third elastic support 6', other parts are substantially identical with those in the first embodiment and thus the description thereof is omitted.
[0075] The electronic device 100' includes a third elastic support 6' and a forth elastic support 9'. The third elastic support 6' includes a third contact part 63' contacting the second electrode 52' at a position near to the second contact part 81'. Preferably, the third contact part 63' is spaced from the second contact part 81'. Alternatively, the third contact part 63' may contact or overlap with the second contact part 81'.
[0076] The forth elastic support 9' include a forth contact part 64' contacting the second electrode 52' at a position different from the second contact part 81' and the third contact part 63'.
[0077] The first contact part 71' is closer to the center of the electronic element 5' than the second contact part 81' and the forth contact part 64', and the second contact part 81' and the forth contact part 64' are opposite to each other across the first contact part 71'. Preferably, said first contact part 71' is position is on the center of the electronic element 5' while a line connecting the second contact part 81' and the forth contact part 64' passes the center of the electronic element 5'. The first contact part 71' abuts the general center of the first electrode 51' of the electronic element 5' and the second contact part 81' abuts the side of the second electrode 52' of the electronic element 5'. The third elastic support 6' applies an elastic force on the electronic element 5' via the third contact part 63'. The forth elastic support 9' applies an elastic force on the electronic element 5' via the forth contact part 64'. Thus the fist support 7' and the second support 8' create a force toward the electronic element 5' against the elastic force of the third support 6'and the forth support 9', so that closer contact is formed between the first contact part 71'and the first electrode 51', and the second contact part 81'and the second electrode 52'. In this way reliable connection is formed between the electronic element 5' and the first terminal 3' and the second terminal 4'.
[0078] One skilled in the art understands that the elastic force applied on the electronic element by the forth support 9' need to be larger than that applied on the electronic element by the third support 6', so that the first support 7' and the second support 8' can apply a force toward the electronic element 5' to realize a close contact.
[0079] In a failure status, the electronic element 5' breaks along a plane passing near the center. The elastic force of the third elastic part 6' with the third contact part 63' drives the fragments of the electronic element 5' away from the second contact part 81', separating the fragments from the second contact part 81'. That is, the second support 8' is out of contact with the second electrode 52'. Since the second support 8' is a rigid support without any compression, when the third elastic support 6' pushes away the fragments, the second support 8' does not contact with the electronic element 5' anymore. In the failure status, the third elastic support 6' and the forth support 9' are insulated with the second support 8' and the second terminal 4'. For instance, the third elastic support 6' and the forth elastic support 9' may be made of an insulated material. Alternatively, in the case that the third elastic support 6' and the forth elastic support 9' are conductive, the third elastic support 6' and the forth elastic support 9' may be spaced from the second support 8' and the second terminal 4' or are spaced via insulated material. Thus the electrical connection between the electronic element 5' and the second terminal 4' is cut, the fragments are disconnected from the circuit and the short cut is prevented.
[0080] One skilled in the art understands that the third elastic support 6' may include two or other numbers of forks and the description thereof is omitted.
Third Embodiment
[0081] Fig. 8 shows a PTC thermistor device according to a third embodiment of the present invention.
[0082] The electronic device 100" includes a first support 7" with a first contact part 71" contacting and electrically connecting with the first electrode 51"; a second support 8" with a second contact part 81" contacting and electrically connecting with the second electrode 52"; and a fifth support 10" with a fifth contact part 82" contacting and electrically connecting with the second electrode 52" at a position different from the second contact part 81 ". The first support 7" is mounted on the first terminal 3" and electrically connected therewith. The second support 8" and the fifth support 10" are mounted on the second terminal 4" and electrically connected therewith. Preferably, the second support 8" may be integral with the fifth support 10". Preferably, the second support 8" and the fifth support 10" may be integral with the second terminal 4". Preferably, the first support 7" may be integral with the first terminal 3". Preferably, the first support 7" is a rigid support. Preferably, the second support 8" and the fifth support 10" are elastic support.
[0083] The electronic device 100" further comprises a third elastic support 6". The third elastic support 6" is such as a spring. The third elastic support has a third contact part 63" contacting the first electrode 51" at a position near to the first contact part 71 ". Preferably, the third contact part 63" is spaced from the first contact part 71 ". Alternatively, the third contact part 63 "may be contact or overlap with the first contact part 71 ".
[0084] Similar as the first embodiment, the third elastic support 6" may include two or other numbers of forks. The first contact part 71" is positioned between the two elastic forks and spaced therefrom. Preferably, the spaced distance between the first contact part 71" and the two forks is less than 2mm.
[0085] The first contact part 71" is closer to the center of the electronic element 5" than the second contact part 81" and the fifth contact part 82", and the second contact part 81" and the fifth contact part 82" are opposite to each other across the first contact part 71". Preferably, said first contact part 71" is position is on the center of the electronic element 5' while a line connecting the second contact part 81" and the fifth contact part 82" passes the center of the electronic element 5".
[0086] The elastic second support 8" applies a second elastic force on the electronic element. The elastic fifth support 10"applies a forth elastic force on the electronic element. The third elastic support 6"applies a first elastic force on the electronic element. The sum of the second elastic force and the fifth elastic force is greater than the first elastic force. Thus, in a normal operation status, the first support 7"creates a force toward the first electrode 51"due to the first elastic force, the second elastic force and the fifth elastic force, so that the first support 7"and the first electrode 51" keep close contact.
[0087] In a failure status when the electronic element breaks, the first elastic force drives the fragments of the electronic element away from the first support 7", causing the first support 7" out of contact with the first electrode 5 1 ", as shown in Fig. 9. Since the first support 7" is a rigid support without any compression, when the third elastic support 6"pushes away the fragments, the first support 7" does not contact with the electronic element 5" anymore. In the failure status, the third elastic support 6" is insulated with the first support 7" and the first terminal 3". For instance, the third elastic support 6" may be made of an insulated material. Alternatively, in the case that the third elastic support 6" is conductive, the third elastic support 6 " may be spaced from the first support 7" and the first terminal 3" or are spaced via insulated material. Thus the electrical connection between the electronic element 5" and the first terminal 3" is cut, the fragments are disconnected from the circuit and the short cut is prevented.
[0088] In the preceding specification, various preferred embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various other modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.
[0089] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.
1. An electronic device includes:
an electronic element with a first electrode and a second electrode disposed on the opposite sides thereof;
a first terminal and a second terminal;
a first support mounted to and electrically connected with the first terminal, the first support comprising a first contact part contacting and electrically connected with the first electrode;
a second support mounted to and electrically connected with the second terminal, the second support comprising a second contact part contacting and electrically connected with the second electrode;
a third elastic support comprising a third contact part contacting with one of the first electrode and the second electrode,
wherein the third elastic support is provided so as to push the electronic element out of contact with one of the first support and the second support when the electronic element breaks in a failure state.
2. The electronic device according to claim 1, wherein the third elastic support is electrically
insulated with said one of the first support and the second support as well as the
terminal electrically connected therewith, when the electronic element breaks in a
failure state.
3. The electronic device according to claim 2, wherein said one of the first support
and the second support is a rigid support.
4. The electronic device according to claim 3, wherein the second support is a rigid
support, and the third contact part contacts with the second electrode at a position
close to the second contact part.
5. The electronic device according to claim 4, wherein the third elastic support comprises
a first elastic part providing the third contact part and a second elastic part including
a forth contact part contacting with the second electrode at a position different
from the second contact part and the third contact part.
6. The electronic device according to claim 5, wherein the first contact part is closer
to the center of the electronic element than the second contact part and the forth
contact part, and the second contact part and the forth contact part is opposite to
each other across the first contact part.
7. The electronic device according to claim 6, wherein the second elastic part applies
a second elastic force on the electronic element, the first elastic part applies a
first elastic force on the electronic element, and the second elastic force is greater
than the first elastic force.
8. The electronic device according to claim 7, wherein fragments of the electronic element
are pushed away from the second support by the first elastic force when the electronic
element breaks in a failure state, so that the second support is out of contact with
the second electrode.
9. The electronic device according to claim 7, wherein in normal status, the first support
applies a force toward the first electrode and the second support applies a force
toward the second electrode due to the first elastic force and the second elastic
force, so that the first support keeps close contact with the first electrode and
the second support keeps close contact with the second electrode.
10. The electronic device according to claim 5, wherein the first elastic part comprises
two elastic forks, the second contact part is positioned between the two forks and
spaced therewith.
11. The electronic device according to claim 10, wherein an elastic force on the electronic
element applied by the second elastic part is greater than the sum of the elastic
force on the electronic element applied by the two forks.
12. The electronic device according to any one of claims 1 to 11, wherein the electronic
element is a positive temperature coefficient (PTC) disc.
13. The electronic device according to any one of claims 1 to 11, wherein the first support
is integral with the first terminal.
14. The electronic device according to any one of claims 1 to 11, wherein the second support
is integral with the second terminal.
15. A method for fabricating an electronic device, the method comprising:
selecting an electronic device that comprises an electronic element with a first electrode and a second electrode disposed on the opposite sides thereof; a first terminal and a second terminal; a first support mounted to and electrically connected with the first terminal, the first support comprising a first contact part contacting and electrically connected with the first electrode; a second support mounted to and electrically connected with the second terminal, the second support comprising a second contact part contacting and electrically connected with the second electrode; a third elastic support comprising a third contact part contacting with one of the first electrode and the second electrode, wherein the third elastic support is provided so as to push the electronic element out of contact with one of the first support and the second support when the electronic element breaks in a failure state; and
disposing the electronic device within a cover and a base.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description