Method of detecting the approach of a user's hand to a vehicle door handle or the contact of a user's hand therewith, and associated detection device
Disclosed is a method of detecting the approach and/or contact of a user's hand to a door handle, the handle having a first outer surface oriented toward the vehicle and a second outer surface oriented toward the user, the handle including at least one detection electrode and an additional electrode, positioned face to face in advance. The method includes: the two electrodes are electrically connected to the same power supply source; a first capacitance value is measured at the terminals of the detection electrode; a second capacitance value is measured at the terminals of the additional electrode; and the first and second values are compared, during a measurement period, with one another and/or with a predetermined threshold value, in order to detect the approach of a user's hand toward the first outer surface or toward the second outer surface and/or the contact of his hand with one of these surfaces.
1. Method of detecting the approach of a user's hand toward a door handle (P) of a vehicle (V), having a first outer surface (S 1 ) oriented toward the vehicle (V) and a second outer surface (S 2 ) oriented toward the user, said handle (P) comprising at least one detection electrode (ED) and an additional electrode (EA), wherein said two electrodes (ED, EA) are positioned face to face in advance, said method comprises the following steps:
Step 1: the detection electrode (ED) and the additional electrode (EA) are electrically connected to the same power supply source (Vcc),
Step 1b: the voltage at the terminals of the additional electrode (V EA ) is reduced to a value lower than that of the supply voltage (Vcc),
Step 2: a first value (C ED ) of capacitance, which varies on the approach of the user's hand, is measured at the terminals of the detection electrode (ED),
Step 2b: the voltage at the terminals of the detection electrode (V ED ) is reduced to a value lower than that of the supply voltage (Vcc),
Step 3: a second value (C EA ) of capacitance, which varies on the approach of the user's hand, is measured at the terminals of the additional electrode (EA),
Step 4: the first value (C ED ) and the second value (C EA ) are compared, during a measurement period, with one another and/or with a predetermined threshold value (T), in order to detect the approach of a user's hand toward the first outer surface (S 1 ) or toward the second outer surface (S 2 ) and/or the contact of his hand with one of these surfaces.
2. Detection method according to claim 1 , wherein, in step 1b, the additional electrode (EA) is electrically connected to the electrical ground.
3. Detection method according to claim 1 , wherein, in step 2b, the detection electrode (ED) is electrically connected to the electrical ground.
4. Detection method according to claim 1 , wherein steps 1 to 3 are repeated recurrently at a predetermined frequency (f) throughout the measurement period (Δ).
5. Detection method according to claim 4 , wherein step 4 consists of:
Step 4a: if, during the measurement period (Δ), the first value (C ED ) is greater than the second value (C EA ), and the first value (C ED ) and the second value (C EA ) are greater than the predetermined threshold value (T), then
Step 5: the approach detection is validated, otherwise
Step 6: there is no validation of the detection.
6. Detection method according to claim 1 , wherein step 4 consists of:
Step 4b: if, during the measurement period (Δ), the first value (C ED ) is greater than the predetermined threshold value (T), and if the second value (C EA ) is lower than the predetermined threshold value (T), then
Step 5: the approach detection is validated, otherwise
Step 6: there is no validation of the detection.
7. Detection method according to claim 1 , the detection electrode (ED) being located near the first outer surface (S 1 ) and the additional electrode (EA) being located between the second outer surface (S 2 ) and the detection electrode (ED), wherein, in step 4, the approach detection consists in detection toward the first outer surface (S 1 ).
8. Detection method according to claim 2 , wherein, in step 2b, the detection electrode (ED) is electrically connected to the electrical ground.
9. Detection method according to claim 2 , wherein steps 1 to 3 are repeated recurrently at a predetermined frequency (f) throughout the measurement period (Δ).
10. Detection method according to claim 2 , wherein step 4 consists of:
Step 4b: if, during the measurement period (Δ), the first value (C ED ) is greater than the predetermined threshold value (T), and if the second value (C EA ) is lower than the predetermined threshold value (T), then
step 5: the approach detection is validated, otherwise
Step 6: there is no validation of the detection.
11. Detection method according to claim 2 , the detection electrode (ED) being located near the first outer surface (S 1 ) and the additional electrode (EA) being located between the second outer surface (S 2 ) and the detection electrode (ED), said method is wherein, in step 4, the approach detection consists in detection toward the first outer surface (S 1 ).
12. Detection method according to claim 3 , wherein steps 1 to 3 are repeated recurrently at a predetermined frequency (f) throughout the measurement period (Δ).
13. Detection method according to claim 3 , wherein step 4 consists of:
Step 4b: if, during the measurement period (Δ), the first value (C ED ) is greater than the predetermined threshold value (T), and if the second value (C EA ) is lower than the predetermined threshold value (T), then
Step 5: the approach detection is validated, otherwise
Step 6: there is no validation of the detection.
14. Detection method according to claim 3 , the detection electrode (ED) being located near the first outer surface (S 1 ) and the additional electrode (EA) being located between the second outer surface (S 2 ) and the detection electrode (ED), wherein, in step 4, the approach detection consists in detection toward the first outer surface (S 1 ).
15. Detection method according to claim 4 , the detection electrode (ED) being located near the first outer surface (S 1 ) and the additional electrode (EA) being located between the second outer surface (S 2 ) and the detection electrode (ED), wherein, in step 4, the approach detection consists in detection toward the first outer surface (S 1 ).
16. Detection method according to claim 5 , the detection electrode (ED) being located near the first outer surface (S 1 ) and the additional electrode (EA) being located between the second outer surface (S 2 ) and the detection electrode (ED), wherein, in step 4, the approach detection consists in detection toward the first outer surface (S 1 ).
17. Device (D′) for detecting the approach of a user's hand toward a door handle (P) of a vehicle (V) and/or the contact of the hand therewith, the handle having a first outer surface (S 1 ) oriented toward the vehicle (V) and a second outer surface (S 2 ) oriented toward the user, said device (D′) comprising at least one voltage source (Vcc), a detection electrode (ED), an additional electrode (EA), and means (M 1 ) for measuring a first value (C ED ) of capacitance at the terminals of the detection electrode (ED) and a second value (C EA ) of capacitance at the terminals of the additional electrode (AE), wherein said two electrodes (EA, ED) are positioned face to face, said device (D′) further comprises:
first connection means (K 1 ) for connecting the detection electrode (ED) to the measurement means (M 1 ),
second connection means (K 2 ) for connecting the additional electrode (EA) to the measurement means (M 1 ),
control means (M 2 ) for controlling the first and second connection means (K 1 , K 2 ), as well as
means (M 3 ) for adjusting the voltage at the terminals of the detection electrode (V ED ) and the voltage at the terminals of the additional electrode (V EA ), for independently controlling the voltage at the terminals of the detection electrode (V ED ) and the voltage at the terminals of the additional electrode (V EA ) from a minimum value equal to the electrical ground to a maximum voltage equal to the supply voltage (Vcc),
a clock (H) connected to the control means (M 2 ),
means (M 4 ) for comparing the first value (C ED ) and the second value (C EA ) with one another and/or with a predetermined threshold value (T).
18. Detection device (D′) according to claim 17 , further comprising means for calculating a mean of the first value (C EDmoy ) and means for calculating a mean of the second value (C EAmoy ) during a measurement period (Δ), and means (M 4 ) for comparing the mean of the first value (C EDmoy ) and the mean of the second value (C EAmoy ) with one another and/or with the predetermined threshold value (T).
19. Motor vehicle door handle (P), comprising a detection device (D′) according to claim 17 .
20. Motor vehicle (V), comprising a detection device (D′) according to claim 17 .