Injection device with a capacitive proximity sensor

• US 8,088,096 B2
• Filed: 01/30/2007
• Issued: 01/03/2012
• 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: Lauchard, Gerhard, Reindl, Martin, Guggenberger, Claudia-Carolin
• Primary Examiner(s): Lucchesi, Nicholas D
• Assistant Examiner(s): Snyder, Melissa A
• Application Number:
  US12/162,052
• Publication Number:
  US 20090216182A1
• Time in Patent Office: 1,799 Days
• Field of Search: 604 65- 67, 604/151, 604/31, 604/131
• US Class Current: 604/66
• 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• CPC Class Codes: A61M 5/322 Retractable needles, i.e. disconnected from and withdrawn into the syringe barrel by the piston devices for protecting guide needles in combination with catheters A61M25/0612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 having a through hole for passage of a needle, further comprising a capacitive proximity sensor for detecting proximity or contact of human skin to/with said surface, said capacitive proximity sensor including a first electrode, a second electrode defining a capacitance with the first electrode and means for detecting a change in said capacitance due to the proximity of human skin to the sensor, and further comprising a compensation electrode for limiting the electric field generated by the first and second electrodes to a determined area.

2. Injection device according to claim 1, further comprising a control unit which allows injection of medication only when detection by the sensor occurs.

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

4. Injection device according to claim 1, wherein said capacitive proximity sensor is so set that detection occurs when a sufficient volume of human tissue has entered an electric field generated by the capacitive proximity sensor, a mere contact of a finger on said surface not being sufficient for the detection to occur.

5. Injection device according to claim 1, wherein said capacitive proximity sensor is so set to substantially not detect dry clothes.

6. Injection device according to claim 1, wherein said capacitive proximity sensor is so set to substantially not detect any of the following materials:

dry cotton, dry leather.

7. Injection device according to claim 1, wherein said capacitive proximity sensor is so set to substantially not detect any of the following materials:

wood, plastic, metal, ceramic, glass.

8. Injection device according to claim 1, wherein feet are provided on said surface to prevent contact of said surface with a rigid surface while permitting contact of said surface with human skin.

9. Injection device according to claim 1, wherein said capacitive proximity sensor is adjacent to said through hole.

10. Injection device according to claim 1, wherein the first and second electrodes are substantially coplanar and disposed in a plane parallel to said surface.

11. Injection device according to claim 10, wherein said first and second electrodes are disposed on an internal surface of an insulating element, said insulating element having an external surface which defines at least part of said surface having said through hole.

12. Injection device according to claim 1, wherein the first electrode surrounds, at least partly, the second electrode.

13. Injection device according to claim 12, wherein the second electrode has an elongate shape.

14. Injection device according to claim 13, wherein the second electrode is disposed within a U-shaped recess defined by the first electrode and is substantially parallel to the legs of the first electrode formed by the U-shaped recess.

15. Injection device according to claim 14, wherein the width (w1, w2) of said legs and the distance (d) between the bottom of the U-shaped recess and a side of the first electrode opposite said bottom are larger than the width (w) of the second electrode.

16. Injection device according to claim 13, wherein a lateral gap (g) between the first and second electrodes is smaller than the width (w) of the second electrode.

17. Injection device according to claim 12, wherein the first electrode is larger than the second electrode.

18. Injection device according to claim 1, wherein one side of the first electrode is adjacent to the through hole and has a concave shape that follows part of the contour of the through hole.

19. Injection device according to claim 1, wherein said means for detecting a change in said capacitance comprises a first electronic circuit which delivers a periodic signal to the first electrode.

20. Injection device according to claim 19, wherein the first electronic circuit is a timer circuit having an output connected to the first electrode, a triggering input and a threshold input, the triggering and threshold inputs being both connected to the second electrode.

21. Injection device according to claim 19, wherein the frequency of the periodic signal depends on said capacitance, and in that said means for detecting a change in said capacitance further comprises a second electronic circuit for detecting a change in said frequency due to the proximity of human skin to the sensor.

22. Injection device according to claim 1, wherein the compensation electrode is disposed in a plane parallel to a plane defined by the first and second electrodes, is connected to the second electrode, and has a shape which substantially corresponds to the contour of the first electrode.