Common calibration system and corresponding method

• US 9,823,060 B2
• Filed: 12/21/2012
• Issued: 11/21/2017
• Est. Priority Date: 12/29/2011
• Status: Active Grant

• Current Assignee: ALPAO
• Original Assignee: ALPAO
• Inventors: Barrault, Michel Raymond
• Primary Examiner(s): Lee, Paul D
• Application Number:
  US14/369,498
• Publication Number:
  US 20140336969A1
• Time in Patent Office: 1,796 Days
• Field of Search: 702 94
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01L 27/002 Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24

Abstract

The invention relates to a system (1) comprising a deformable surface (2) and a first and a second sensor (C1, C2) designed to provide a first and a second measurement signal (S1, S2) intended to be collected by a processing circuit (12), said system (1) comprising first and second measurement paths (V1, V2) for collecting the first and second measurement signals (S1, S2), said system (1) being characterized in that it comprises a common calibration member (20) for simultaneously injecting into the first and second measurement paths (V1, V2) a calibration signal (S_E), said common calibration member (20) being designed so that the image signals (S′1, S′2, S′n) restored via said measurement paths (V1, V2, Vn) are independent of said movable surface (2). Deformable movable surface systems, of the deformable mirror type.

Claims

1. A system comprising a mobile and/or deformable surface (2) as well as at least one first and one second sensor (C1, C2) designed to provide respectively a first and a second measurement signal (S1, S2) relating to the shape and/or to the position of said mobile and/or deformable surface (2) and intended to be gathered by a processing circuit (12) designed to determine the shape and/or the position of said mobile and/or deformable surface (2) on the basis of said measurement signals (S1, S2), said system (1) comprising for this purpose at least one first measurement pathway (V1) for gathering the first measurement signal (S1) and at least one second measurement pathway (V2) for gathering the second measurement signal (S2), said system (1) being characterized in that it comprises a common calibration member (20) for injecting a known calibration signal (S_E) simultaneously into at least the first measurement pathway (V1) and the second measurement pathway (V2) so as to allow the calibration of all or part of the processing circuit (12), said common calibration member (20) being designed such that image signals (S′

1, S′

2) retrieved by said measurement pathways (V1, V2) in response to injection of said calibration signal (S_E) are substantially independent of the shape and of the position of said mobile and/or deformable surface (2).

2. The system of claim 1, characterized in that said processing circuit (12) is a servocontrol circuit controlling the deformation and/or the displacement of said mobile and/or deformable surface (2).

3. The system of claim 1, characterized in that, the first and the second measurement pathways (V1, V2) are formed by conducting tracks (22), and the common calibration member (20) is formed by an electrode (23) common to said tracks (22).

4. The system of claim 3, characterized in that the common calibration member (20) comprises a plurality of conducting spans (24) electrically linked together and each disposed substantially plumb with the corresponding sensor (C1, C2), on the opposite side of the mobile and/or deformable surface (2) with respect to said sensor.

5. The system claim 1, characterized in that the common calibration member (20) is separated from the first and second measurement pathways (V1, V2) by a dielectric layer (24) and cooperates with said measurement pathways by capacitive coupling.

6. The system of claim 1, characterized in that the common calibration member (20) and the measurement pathways (V1, V2) belong to one and the same multilayer structure (30), of the printed circuit board kind.

7. The system of claim 6, characterized in that the multilayer structure (30) forms a rigid reference support (14), with respect to which the mobile and/or deformable surface (2) moves when it deforms, and which carries the sensors (C1, C2).

8. The system of claim 6, characterized in that it comprises a plurality of actuators (6) each possessing a mobile rig (7) fixed to the mobile and/or deformable surface (2) so as to be able to locally drive the mobile and/or deformable surface (2) in displacement, and in that the multilayer structure (30) is drilled with passages (32) allowing said mobile rigs (7) to pass through it.

9. The system of claim 6, characterized in that the multilayer structure (30) exhibits a first protection screen (33) and a second protection screen (34) remote from the first protection screen (33), said screens (33, 34) being electrically conducting so as to form an electromagnetic shielding delimiting a tunnel (35) through which the measurement pathways (V1, V2) pass.

10. The system of claim 9, characterized in that the calibration member (20) is formed by an electrode (23) belonging to the same conducting layer as that of the first protection screen (33) or of the second protection screen (34), said electrode forming a peripheral span externally bordering the protection screen or an intermediate span substantially nested between two concentric portions (33A, 33B, 34A, 34B) of said screen.

11. The system claim 1, characterized in that it comprises a network of sensors (C1, C2) disposed substantially plumb with the mobile and/or deformable surface (2), in that the measurement pathways (V1, V2) are offset from their respective sensor toward the periphery of the system 1, and in that the calibration member (20) is disposed at the periphery of said system (1), and preferably formed by an electrode (23) which surrounds the whole of the array of sensors (C1, C2).

12. The system of claim 1, characterized in that it comprises a network of at least 10, 20, 50 or 100 sensors (C1, C2), each recorded by a distinct measurement pathway (V1, V2), and in that the calibration member (20) is common to the whole set of said measurement pathways (V1, V2).

13. The system claim 1, characterized in that the sensors (C1, C2) constitute position sensors for locally recording the variable position of the mobile and/or deformable surface (2) with respect to a reference support (14) integrated into the system.

14. The system claim 1, characterized in that the common calibration member (20) is associated with switching means (25) for connecting it up either to a calibration signal generator (21), or to ground.

15. The system claim 1, characterized in that the common calibration member (20) occupies an invariant position with respect to the first and second measurement pathways (V1, V2).

16. The system of claim 1, characterized in that said mobile and/or deformable surface (2) is formed by an electrically conducting membrane.

17. The system of claim 1, characterized in that it constitutes a deformable mirror, said mobile and/or deformable surface (2) forming a reflector member.

18. A method of calibrating a processing circuit (12) of a system (1) comprising a mobile and/or deformable surface (2) as well as at least one first and one second sensor (C1, C2) designed to provide respectively a first and a second measurement signal (S1, S2) relating to the shape and/or to the position of said mobile and/or deformable surface (2) and intended to be gathered, by means respectively of a first and of a second measurement pathway (V1, V2), by said processing circuit (12), which is designed to determine the shape and/or the position of said mobile and/or deformable surface (2) on the basis of said measurement signals (S1, S2), said method being characterized in that it comprises a step (a) of common calibration which comprises a sub-step (a1) of injection in the course of which a predefined calibration signal (S_E) is injected simultaneously into each of the measurement pathways (V1, V2), and then a sub-step (a2) of comparison, in the course of which image signals (S′

1, S′

2) retrieved by said measurement pathways (V1, V2) are compared with the calibration signal (S_E) which corresponds to them, the image signals (S′

1, S′

2) being substantially independent of the shape and of the position of said mobile surface (2), and then a sub-step (a3) of correction in the course of which one or more characteristics of the processing circuit (12), such as the respective gain of each measurement pathway (V1, V2), is or are modified so as to obtain at the level of each pathway an image signal which corresponds to the calibration signal (S_E) which is applied to it.

19. The calibration method of claim 18, characterized in that said processing circuit (12) is a servocontrol circuit controlling the deformation and/or the displacement of said mobile and/or deformable surface (2).