Optical Distance Measuring Device

• US 20120249998A1
• Filed: 07/15/2010
• Published: 10/04/2012
• Est. Priority Date: 09/11/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Eisele, Andreas, Wolst, Oliver, Schmidtke, Bernd
• Granted Patent: US 8,908,157 B2
• Time in Patent Office: Days
• US Class Current: 356/5.01
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/491 Details of non-pulse systems
• CPC Class Codes: G01S 7/4913 Circuits for detection, sampling, integration or read-out

Abstract

A measuring device for optically measuring a distance to a target object includes an emitter device for emitting an optical measuring beam to the target object, a capturing device including a detection surface for detecting an optical beam returned by the target object, and an evaluation device. The detection surface has a plurality of pixels, each pixel having at least one SPAD (single photon avalanche diode) and each of the plurality of pixels is connected to the evaluation device. The emitting device and the capturing device are configured in such a manner that the optical measurement beam returned by the target object simultaneously illuminates a plurality of pixels. The evaluation device is configured in order to determine the distance between the measuring device and the target object based on the evaluation of detection signals of several pixels.

Claims

1. A measuring device for optical distance measurement, in particular a handheld measuring device, comprising:

a transmitting unit for emitting optical measurement radiation toward a target object;

a receiving unit having a detection area for detecting optical measurement radiation returning from the target object; and

an evaluation unit,

wherein the detection area has a multiplicity of pixels,

wherein each pixel has at least one SPAD,

wherein each of the multiplicity of pixels is connected to the evaluation unit,

wherein the transmitting unit and the receiving unit are designed in such a way that optical measurement radiation returning from the target object simultaneously illuminates a plurality of pixels, and

wherein the evaluation unit is designed to determine a distance between the measuring device and the target object on the basis of an evaluation of detection signals of a plurality of pixels.

2. The measuring device as claimed in claim 1, wherein the evaluation unit has at least one distance determining unit designed to determine a time of flight of measurement radiation between emission by the transmitting unit until detection of measurement radiation returning from the target object and to determine a distance therefrom.

3. The measuring device as claimed in claim 2, wherein:

a plurality of pixels are connected to a distance determining unit, and

the distance determining unit is designed to determine the distance on the basis of detection signals of the plurality of pixels.

4. The measuring device as claimed in claim 2, wherein:

the evaluation unit has a plurality of distance determining units, and

the evaluation unit is designed to determine the distance between the measuring device and the target object on the basis of the distances determined by the distance determining units.

5. The measuring device as claimed in claim 1, wherein at least some pixels each contain a plurality of SPADs.

6. The measuring device as claimed in claim 5, furthermore comprising:

at least one combiner configured to combine detection signals of SPADs which are contained in an individual pixel.

7. The measuring device as claimed in claim 5, furthermore comprising:

at least one pulse shortener in order to temporally shorten a digital signal generated by an SPAD.

8. The measuring device as claimed in claim 5, wherein the number of SPADs contained in a pixel varies depending on the location of the pixel within the detection area of the receiving unit.

9. The measuring device as claimed in claim 5, wherein an area of SPADs contained in a pixel varies depending on the location of the pixel within the detection area of the receiving unit.

10. The measuring device as claimed in claim 8, wherein:

the transmitting unit and the receiving unit are arranged alongside one another along a parallax axis, and

the number of SPADs contained in a pixel varies depending on the location along the parallax axis.

11. The measuring device as claimed in claim 8, wherein the number of SPADs contained in a pixel is smaller in pixels near the transmitting unit than in pixels remote from the transmitting unit.

12. The measuring device as claimed in claim 8, wherein the number of SPADs contained in a pixel is smaller in pixels near the center of the detection area than in pixels remote from the center of the detection area.

13. The measuring device as claimed in claim 1, wherein the transmitting unit and the receiving unit are designed in such a way that a number of pixels which are illuminated simultaneously by optical measurement radiation returning from the target object varies in a manner dependent on a distance between the target object and the measuring device.

14. The measuring device as claimed in claim 1, furthermore comprising:

a non-automatically focusing optical unit for directing optical measurement radiation returning from the target object onto the detection area.

15. The measuring device as claimed in claim 1, wherein the receiving unit and the evaluation unit are designed for the purpose that detection signals of individual pixels can be evaluated independently of detection signals of other pixels by the evaluation unit.

16. The measuring device as claimed in claim 1, wherein the receiving unit and the evaluation unit are designed to determine a distance between the measuring device and the target object on the basis of an evaluation of detection signals exclusively of pixels within an effective detection area, onto which light from that area of the target object which is illuminated by the transmitting unit is radiated back.

17. The measuring device as claimed in claim 1, furthermore comprising:

at least one multiplexer designed to forward detection signals of a plurality of pixels selectively to the evaluation unit.