Optical position transmitter with analog memory unit

Patent metadata

Field	Value
Publication number	US-9482560-B2
Application number	US-201314412641-A
Country	US
Kind code	B2
Filing date	Jul 4, 2013
Priority date	Jul 4, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

The invention relates to a position transmitter with a position code and an optical sensor element for detecting at least one part of the position code. The sensor element has a row of photosensitive detection regions, which convert incident photons into electric charges, and a readout structure for outputting an electric data signal corresponding to the stored electric charges. The sensor element has an analog memory unit structure with a number of N>1 rows of photo-insensitive analog memory cells in order to temporarily store the electric charges and an electric switching structure, by means of which a charge transfer can be carried out between the detection regions and the memory cells, between the memory cells amongst one another, and between the memory cells and the readout row.

First claim

What is claimed is:

1. A position encoder, comprising a position code and an optical sensor element for acquiring at least part of the position code, wherein the sensor element comprises:
a line of photosensitive acquisition regions, which convert incident photons (p) into electric charges; and
a readout structure for outputting an electric data signal corresponding to the electric charges, wherein:
the sensor element, for the purposes of temporarily storing the electric charges, comprises:
an analog memory array structure with a number of N>1 lines of photo-insensitive analog memory cells, wherein the number of lines of memory cells is greater than a multiple of, the number of acquisition regions; and
an electrical switching structure, by means of which switching structure a charge transfer is performable between the acquisition regions, the memory cells and the readout structure and which is configured in such a way that the charge transfer is in-between the lines of memory cells from one line to another line and is performable for individual lines or for a subset of the lines in the memory structure, wherein an upper part of the lines in the memory structure is shiftable independently of a lower part of the lines in the memory structure.

2. The position encoder as claimed in claim 1 , wherein:
the switching structure is configured in such a way that:
a trigger signal renders it possible to set a time of acquisition of the position code and of transferring the charges from the acquisition regions into the memory structure; and
a readout signal asynchronous to the trigger signal renders it possible to set a time of the output by the readout structure.

3. The position encoder as claimed in claim 1 , wherein:
the sensor element comprises:
a single line of photosensitive acquisition regions;
at least N≧3 lines of memory cells; and
a single readout structure.

4. The position encoder as claimed in claim 1 , wherein:
the switching structure renders possible performing the transfer of the electric charges:
between the line of acquisition regions and one of the lines of analog memory cells at an acquisition time predetermined by the trigger signal;
between the lines of analog memory cells amongst themselves, wherein the transfer is selectively actuatable for each one of these lines of memory cells or actuatable for a proper subset of the lines of memory cells;
between at least one of the lines of analog memory cells and the readout structure, by the readout signal for reading out the position code acquired at the acquisition time; and
wherein at least a second acquisition is performable between a first acquisition and completion of an associated first readout of the first acquisition, the charges of which second acquisition are temporarily stored in the memory structure in analog manner and which can be read out at a later time in an at least second readout following the first readout.

5. The position encoder as claimed in claim 1 , wherein:
the sensor element comprises a discharge structure, which is configured in such a way that charges possibly present in one of the analog memory cells are discharged before there is a charge transfer into these memory cells, wherein the discharge structure is selectively applicable to a subset of the number N of lines of the analog memory structure.

6. The position encoder as claimed in claim 1 , wherein:
the analog memory structure comprises a memory manager, which controls the charge transfer on the basis of a trigger signal and of a readout signal and which is configured in such a way that:
on the basis of the readout signal, a transfer of the charges in the memory structure in the direction of the readout structure and the output of a data signal in the readout structure on the basis of the analog memory values take place; and
on the basis of the trigger signal, it is possible to perform a transfer of the charges from the acquisition regions into a line in the memory structure, which lies closest to the readout structure and in which no charges are stored yet, wherein the output is effected asynchronously in relation to the trigger.

7. The position encoder as claimed in claim 1 , wherein:
the sensor element is installed with a CCD with a CMOS structure on a common semiconductor substrate, wherein the analog memory structure is built in CCD technology and the readout structure is built in CMOS technology.

8. The position encoder as claimed in claim 1 , wherein:
the sensor element is provided with a correlated double sampling structure.

9. The position encoder as claimed in claim 1 , wherein:
the sensor element is provided with the correlated double sampling structure in that line of the analog memory structure from which the transfer into the readout structure is effected.

10. The position encoder as claimed in claim 1 , wherein:
the line of acquisition regions comprises at least one dark pixel, which is protected against incident photons (p) and in which no charges are generated by photons and the charges of which are also transferred during a line-by-line transfer as a dark reference.

11. A method for optical acquisition of at least part of a position code by a line of photosensitive acquisition elements, comprising:
an acquisition and conversion of photons into electric charges in the acquisition elements; and
an output—triggered by a readout signal—of an electric data signal corresponding to the electric charges, wherein:
triggering a time of the optical acquisition by an external trigger signal and, triggered thereby, transferring the electric charges from the acquisition elements into a memory structure configured as an array with N>1 lines of analog memory cells, wherein the number of lines in the memory structure is greater than the number of acquisition elements;
temporary buffer storing of the analog charges in this memory structure prior to the output, during which the transfer in the memory structure to individual lines or to a subset of the lines in-between the lines of the memory structure is performed selectively, wherein an upper part of the lines in the memory structure is shiftable independently of a lower part of the lines in the memory structure; and
wherein, as a result of the buffer storing, the acquisition can be effected asynchronously in relation to the output.

12. The method as claimed in claim 11 , wherein:
a switching structure is used to perform;
caused by a trigger signal;
a transfer of charges from the line of photosensitive acquisition regions into one of the lines of the analog memory structure;
caused by a readout signal;
a transfer of charges from one of the lines in the analog memory structure into a readout structure;
the output of the electric data signal from the readout structure;
are performed; and
wherein the readout signal is controllable in a time-independent manner from the trigger signal.

13. The method as claimed in claim 11 , wherein the transfer of charges from one of the lines in the analog memory structure into a readout structure includes an advance of at least those lines in the memory structure in which acquired charges are buffer stored.

14. The method as claimed in claim 11 , wherein:
the memory structure is managed as line-by-line shift register,
selective erasing of a subset of the lines in the memory structure is performable,
there is selective erasing of one of the lines prior to the transfer of charges into this line.

15. The method as claimed in claim 11 , wherein:
depending on the trigger signal, the charges from the acquisition regions are either:
di

Assignees

• Hexagon Technology Ct Gmbh

Inventors

• Fritsch Robert

Classifications

• G01D5/26 Primary

  characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light · CPC title

• G01D9/30

  there being a separate recording element for each variable, e.g. multiple-pen recorder · CPC title

• G01B5/008

  using coordinate measuring machines · CPC title

• G01D5/262 Primary

  with optical projection of a pointer or a scale · CPC title