Device for determining the position of a horological display

Patent metadata

Field	Value
Publication number	US-12326696-B2
Application number	US-202117319144-A
Country	US
Kind code	B2
Filing date	May 13, 2021
Priority date	Oct 14, 2020
Publication date	Jun 10, 2025
Grant date	Jun 10, 2025

Abstract

A device for determining a position of a horological display, the device including a control device coordinating a time base, a shape recognition device, and an optical acquisition device. The control device identifies the display and monitors its travel in order to code its instantaneous position in relation to a fixed guide-mark, and controls entries of its position at distinct instants in time to determine its mobility in relation to the fixed guide-mark. The device includes a device for determining the depth position of the display in relation to the fixed guide-mark, a device for controlling the position of the optical acquisition device, a device for controlling a focus of the optical acquisition device, and an additional optical acquisition device coupled with the optical acquisition device to interferentially monitor the display.

First claim

The invention claimed is:

1. A method for determining an instantaneous position of a display hand of a timepiece, the method comprising:
controlling a first camera and a second camera to identify the display hand, and monitor movement of the display hand so as to code the instantaneous position of the display hand in relation to a fixed guide-mark, and controlling entries of the instantaneous position at distinct instants to determine mobility of the display hand in relation to the fixed guide-mark, wherein the controlling further comprises:
controlling a position of the first camera and a position of the second camera, in relation to the fixed guide-mark, wherein the second camera and the first camera are, in projection over a plane of the fixed guide-mark, disposed at a distance from one another for stereoscopic imaging,
controlling a focus of the first camera and a focus of the second camera, in relation to the display hand,
determining a depth position of a plane of the display hand in relation to the plane of the fixed guide-mark by controlling the position of the first camera in relation to the plane of the fixed guide-mark, controlling the second camera coupled with the first camera and determining the depth position of the display hand by stereoscopic vision, and
monitoring, by the first camera and the second camera, the display hand and determining the instantaneous position of the display hand in space from signals obtained from the first and second cameras.

2. The method according to claim 1 , wherein the display hand is moveable in the plane of the display hand in relation to the fixed guide-mark, which includes a location index and/or a location scale,
wherein the method further comprises determining a relative position of the display hand in relation to the fixed guide-mark associated with a particular instant identified in relation to a time base,
wherein the method further comprises controlling, at the distinct instants, entries of the instantaneous position of the display hand and comparing the instantaneous positions with the distinct instants to determine the movement of the display hand in relation to the associated fixed guide-mark,
wherein the first camera is arranged to perform a substantially frontal image entry in relation to the plane of the display hand in which the display hand is moveable, and
wherein, to ensure an identification of the display hand, the method further comprises determining the depth position of the plane of the display hand in relation to the plane of the fixed guide-mark with which the plane of the display hand is parallel, the depth position being perpendicular to the plane of the fixed guide-mark.

3. The method according to claim 1 , further comprising performing an oblique or transverse image entry in relation to the plane of the display hand, wherein the display hand is moveable, to determine the depth position of the plane of the display hand in relation to the plane of the fixed guide-mark with which the plane of the display hand is parallel, the depth position being perpendicular to the plane of the fixed guide-mark, so as to confirm a correct identification of the display hand and to improve each entry of the position of the display hand.

4. The method according to claim 1 , wherein the first camera is centered on an axis of rotation of the display hand when the display hand is a rotary display hand.

5. The method according to claim 1 , wherein, the display hand is moveable by periodic jumps, and the distinct instants are separated by a duration greater than a period of the jumps.

6. The method according to claim 1 , wherein the first camera is moveable in relation to the fixed guide-mark, at least in distance.

7. The method according to claim 1 , wherein the first camera includes an auto-focus device for automatic focusing.

8. The method according to claim 1 , further comprising determining the instantaneous position, at a same instant, of the display hand and another display hand of the timepiece.

9. A method for determining an instantaneous position of a display hand of a timepiece, the method comprising:
controlling a camera to identify the display hand, and monitor movement of the display hand so as to code the instantaneous position of the display hand in relation to a fixed guide-mark, and controlling entries of the instantaneous position at distinct instants to determine mobility of the display hand in relation to the fixed guide-mark, wherein the controlling further comprises:
controlling a position of the camera in relation to the fixed guide-mark,
controlling a focus of the camera in relation to the display hand,
illuminating the display hand so as to project a shadow on a fixed surface in relation to which an illumination source has a variable incidence and/or a variable position,

wherein the method further comprises:
capturing, with the camera, a first image of the shadow with the illumination source at a first illumination position,
determining a first position of the shadow with respect to the fixed guide-mark using the captured first image,
capturing, with the camera, a second image of the shadow with the illumination source at a second illumination position different from the first illumination position,
determining a second position of the shadow with respect to the fixed guide-mark using the captured second image, and
determining the instantaneous position of the display hand based on the first position of the shadow, the second position of the shadow, the first illumination position, and the second illumination position.

10. A method for determining an instantaneous position of a display hand of a timepiece, the method comprising:
controlling a first camera and a second camera to identify the display hand, and monitor movement of the display hand so as to code the instantaneous position of the display hand in relation to a fixed guide-mark, and controlling entries of the instantaneous position at distinct instants to determine mobility of the display hand in relation to the fixed guide-mark, wherein the controlling further comprises:
controlling a position of the first camera and a position of the second camera, in relation to the fixed guide-mark,
controlling a focus of the first camera and a focus of the second camera, in relation to the display band,
determining a depth position of a plane of the display hand in relation to a plane of the fixed guide-mark, by performing an oblique or transverse image entry in relation to the plane of the display hand, wherein the display hand is moveable, to determine the depth position of the plane of the display hand in relation to the plane of the fixed guide-mark with which the plane of the display hand is parallel, the depth position being perpendicular to the plane of the fixed guide-mark, so as to confirm a correct identification of the display hand and to improve each entry of the position of the display hand, and
monitoring, by the first camera and the second camera, the display hand and determining the instantaneous position of the display hand in space from signals obtained from the first and second cameras.

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Favre Jérôme
• Kalbermatter Stefan
• Farah Hicham

Classifications

• H04N13/204

  using stereoscopic image cameras (stereoscopic photography G03B35/00) · CPC title

• G04D7/004

  Optical measuring and testing apparatus · CPC title

• G04B5/02

  by self-winding caused by the movement of the watch {(bearings, suspensions for oscillating weights G04B5/18; mechanisms for transformation of an oscillating movement into a rotating movement in only one direction G04B11/00)} · CPC title

• G04D7/1264

  for complete clockworks · CPC title

• G04B5/00 Primary

  Automatic winding up {(normal winding up by hand or mechanically G04B3/00; automatic winding in combination with hand winding G04B7/00; electrical winding of mechanical clockworks G04C1/00; advertising by making use of vibrations or shocks of land vehicles G09F21/045)} · CPC title