INJECTION DEVICE WITH A CAPACITIVE PROXIMITY SENSOR

• US 20090216182A1
• Filed: 01/30/2007
• Published: 08/27/2009
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Ares Trading SA (Merck & Co., Inc.)
• Original Assignee: Ares Trading SA (Merck & Co., Inc.)
• Inventors: Reindl, Martin, Guggenberger, Claudia-Carolin, Lauchard, Gerhard
• Granted Patent: US 8,088,096 B2
• Time in Patent Office: Days
• US Class Current: 604/65
• CPC Class Codes: A61M 2005/206 With automatic needle insertion
• CPC Class Codes: A61M 2005/208 Release is possible only when device is pushed against the skin, e.g. using a trigger which is blocked or inactive when the device is not pushed against the skin
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/322 Retractable needles, i.e. disconnected from and withdrawn into the syringe barrel by the piston devices for protecting guide needles in combination with catheters A61M25/0612
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes

Abstract

An injection device for injecting medication to a patient, comprising a surface (5) having a through hole (3) for passage of a needle, is characterised by further comprising a capacitive proximity sensor (12, 13, 30) for detecting proximity or contact of human skin to/with said surface (5).

Claims

1. Injection device for injecting medication to a patient, comprising a surface (5) having a through hole (3) for passage of a needle (3a), characterised by further comprising a capacitive proximity sensor (12, 13, 30) for detecting proximity or contact of human skin to/with said surface (5).

2. Injection device according to claim 1, characterised by further comprising a control unit (35) which allows injection of medication only when detection by the sensor (12, 13, 30) occurs.

3. Injection device according to claim 2, characterised by further comprising a mechanism (3c) for moving the needle (3a) between a retracted position, inside the device, and an operating position, in which the needle (3a) protrudes from the through hole (3), said control unit (35) allowing the mechanism (3c) to move the needle (3a) from the retracted position to the operating position only when detection by the sensor (12, 13, 30) occurs.

4. Injection device according to claim 1, characterised in that said capacitive proximity sensor (12, 13, 30) is so set that a mere contact of a finger on said surface (5) is not detected.

5. Injection device according to claim 1, characterised in that said capacitive proximity sensor (12, 13, 30) is so set to substantially not detect dry clothes.

6. Injection device according to claim 1, characterised in that said capacitive proximity sensor (12, 13, 30) is so set to substantially not detect any of the following materials:

dry cotton, dry leather.

7. Injection device according to claim 1, characterised in that said capacitive proximity sensor (12, 13, 30) is so set to substantially not detect any of the following materials:

wood, plastic, metal, ceramic, glass.

8. Injection device according to claim 1, characterised in that feet (31) are provided on said surface (5) to prevent contact of said surface (5) with a rigid surface while permitting contact of said surface (5) with human skin.

9. Injection device according to claim 1, characterised in that said capacitive proximity sensor (12, 13, 30) is adjacent to said through hole (3).

10. Injection device according to claim 1, characterised in that said capacitive proximity sensor comprises a first electrode (12), a second electrode (13) defining a capacitance with the first electrode (12) and means (30) for detecting a change in said capacitance due to the proximity of human skin to the sensor.

11. Injection device according to claim 10, characterised in that the first and second electrodes (12, 13) are substantially coplanar and disposed in a plane parallel to said surface (5).

12. Injection device according to claim 11, characterised in that said first and second electrodes (12, 13) are disposed on an internal surface (11) of an insulating element (4), said insulating element (4) having an external surface which defines at least part of said surface (5) having said through hole (3).

13. Injection device according to claim 10, characterised in that the first electrode (12) surrounds, at least partly, the second electrode (13).

14. Injection device according to claim 13, characterised in that the second electrode (13) has an elongate shape.

15. Injection device according to claim 14, characterised in that the second electrode (13) is disposed within a U-shaped recess (18) defined by the first electrode (12) and is substantially parallel to the legs (19, 20) of the first electrode (12) formed by the U-shaped recess (18).

16. Injection device according to claim 15, characterised in that the width (w1, w2) of said legs (19, 20) and the distance (d) between the bottom (21) of the U-shaped recess (18) and a side (15) of the first electrode (12) opposite said bottom (21) are larger than the width (w) of the second electrode (13).

17. Injection device according to claim 14, characterised in that the lateral gap (g) between the first and second electrodes (12, 13) is smaller than the width (w) of the second electrode (13).

18. Injection device according to claim 13, characterised in that the first electrode (12) is larger than the second electrode (13).

19. Injection device according to claim 10, characterised in that one side (14) of the first electrode (12) is adjacent to the through hole (3) and has a concave shape that follows part of the contour of the through hole (3).

20. Injection device according to claim 10, characterised in that said means (30) for detecting a change in said capacitance comprises a first electronic circuit (32) which delivers a periodic signal to the first electrode (12).

21. Injection device according to claim 20, characterised in that the first electronic circuit (32) is a timer circuit (32) having an output connected to the first electrode (12), a triggering input and a threshold input, the triggering and threshold inputs being both connected to the second electrode (13).

22. Injection device according to claim 20, characterised in that the frequency of the periodic signal depends on said capacitance, and in that said means (30) for detecting a change in said capacitance further comprises a second electronic circuit (34) for detecting a change in said frequency due to the proximity of human skin to the sensor.

23. Injection device according to claim 10, characterised by further comprising a compensation electrode (44) for limiting the electric field generated by the first and second electrodes (40, 41) to a determined area.

24. Injection device according to claim 23, characterised in that the compensation electrode (44) is disposed in a plane parallel to a plane defined by the first and second electrodes (40, 41), is connected to the second electrode (41), and has a shape which substantially corresponds to the contour of the first electrode (40).