Method for operating a mems system, and MEMS system

Patent metadata

Field	Value
Publication number	US-12204094-B2
Application number	US-202017293744-A
Country	US
Kind code	B2
Filing date	Jan 11, 2020
Priority date	Feb 21, 2019
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

A method for operating a MEMS system having a projection unit for providing an image via a light beam, and a deflecting unit for the two-dimensional deflection of the at least one light beam. The method includes: driving the deflecting unit via a reference signal, so that the deflecting unit periodically deflects a light beam at least two-dimensionally, measuring a controlled variable of the deflecting unit that corresponds to an actual position of the deflected light beam, ascertaining a current deviation of the controlled variable from a target variable that corresponds to a target position of the light beam, calculating a compensating variable based on the ascertained deviation, controlling the deflecting unit and/or controlling the projection unit based on the calculated compensating variable for reducing the deviation of the light beam from the target position. The compensating variable is additionally calculated based on an earlier deviation in an earlier period.

First claim

What is claimed is:

1. A method for operating a MEMS system having at least one projection unit configured to provide an image via at least one light beam, and a deflection unit configured to at least two-dimensionally deflect the at least one light beam, the method comprising the following steps:
driving the deflecting unit using at least one reference signal, so that the deflecting unit periodically deflects the at least one light beam at least two-dimensionally;
measuring at least one controlled variable of the deflecting unit that corresponds to an actual position of the deflected light beam;
ascertaining a current deviation of the at least one controlled variable from a target variable that corresponds to a target position of the light beam;
calculating at least one compensating variable based on the ascertained deviation; and
controlling the deflecting unit with regard to the deflection and/or controlling the projection unit with regard to the image provision, wherein the controlling of the deflecting unit and/or the controlling of the projection unit is based on the calculated at least one compensating variable for reducing a deviation of the light beam from the target position;
wherein the at least one compensating variable additionally is calculated based on an earlier deviation in at least one earlier period, for the controlling of the deflecting unit,
wherein the at least one compensating variable is calculated within a specifiable frequency control interval.

2. The method as recited in claim 1 , wherein the at least one reference signal is provided in the form of a periodic bandwidth-limited signal.

3. The method as recited in claim 2 , wherein the at least one reference signal is wave-shaped.

4. The method as recited in claim 1 , wherein the calculation of the at least one compensating variable is done using a predictor.

5. The method as recited in claim 4 , wherein the predictor is a Smith predictor.

6. The method as recited in claim 1 , wherein a brightness of the deflected light beam is adapted, using an adaptation unit, as a function of the actual position.

7. The method as recited in claim 1 , wherein the light beam is deflected by the deflecting unit at least two-dimensionally, by deflection with different speeds about at least two different axes.

8. The method as recited in claim 7 , wherein the driving of the deflecting unit takes place via two reference signals, the two reference signals having different frequencies, and a deflection via the deflecting unit taking place in such a way that using a first of the two reference signals a deflection takes place about one of the two different axes, and using the second of the two reference signals, a deflection takes place about a second of the two different axes.

9. A method for operating a MEMS system having at least one projection unit configured to provide an image via at least one light beam, and a deflection unit configured to at least two-dimensionally deflect the at least one light beam, the method comprising the following steps:
driving the deflecting unit using at least one reference signal, so that the deflecting unit periodically deflects the at least one light beam at least two-dimensionally;
measuring at least one controlled variable of the deflecting unit that corresponds to an actual position of the deflected light beam;
ascertaining a current deviation of the at least one controlled variable from a target variable that corresponds to a target position of the light beam;
calculating at least one compensating variable based on the ascertained deviation; and
controlling the deflecting unit with regard to the deflection and/or controlling the projection unit with regard to the image provision, wherein the controlling of the deflecting unit and/or the controlling of the projection unit is based on the calculated at least one compensating variable for reducing a deviation of the light beam from the target position;
wherein the at least one compensating variable additionally is calculated based on an earlier deviation in at least one earlier period, for the controlling of the deflecting unit,
wherein the at least one compensating variable is calculated within a specifiable frequency control interval, and the at least one reference signal is provided from at least one fundamental harmonic of a sawtooth signal, the at least one fundamental harmonic being provided within the frequency control interval.

10. A MEMS system, comprising:
a projection unit configured to provide an image via at least one light beam;
a deflecting unit configured to periodically deflect a light beam incident on the deflecting unit about two axes, based on at least one reference signal;
a measuring unit configured to measure at least one controlled variable of the deflecting unit that corresponds to an actual position of the deflected light beam;
a deviation measuring unit configured to ascertain a current deviation of the at least one controlled variable from a target variable that corresponds to a target position of the light beam;
a predictor unit configured to calculate at least one compensating variable based on the ascertained deviation; and
a controlling unit configured to control the deflecting unit with regard to the deflection and/or to control the projection device with regard to the image provision, based on the calculated at least one compensating variable for reducing a deviation of the light beam from the target position, in which, for the controlling of the deflecting unit, the at least one compensating variable is additionally calculated by the predictor unit based on an earlier deviation in at least one earlier period,
wherein the at least one compensating variable is calculated within a specifiable frequency control interval.

11. The MEMS system as recited in claim 10 , wherein the deflecting unit includes a MEMS mirror that is movable about at least two axes or at least two MEMS mirrors each movable about a respective axis, the at least two axes having different orientations.

12. The MEMS system as recited in claim 10 , wherein the controlling unit includes an integrator and an anti-windup unit.

13. The MEMS system as recited in claim 10 , wherein the predictor unit is configured to carry out the calculation based on a Smith predictor.

14. The MEMS system as recited in claim 10 , wherein the controlling unit includes a closed linear control loop for controlling at least one of the axes of the deflecting unit.

Assignees

• Bosch Gmbh Robert

Inventors

• Gering Stefan
• Petersen Andreas
• Schuster Florian

Classifications

• G09G3/002

  to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT · CPC title

• G09G3/346

  based on modulation of the reflection angle, e.g. micromirrors (micromirrors devices per se G02B26/0833) · CPC title

• G09G3/025

  with scanning or deflecting the beams in two directions or dimensions · CPC title

• H04N9/3194

  including sensor feedback · CPC title

• H04N9/3135 Primary

  Driving therefor · CPC title