CN112013769A

CN112013769A - Signal sensing device for displacement sensor and application method thereof

Info

Publication number: CN112013769A
Application number: CN201910454931.1A
Authority: CN
Inventors: 林立; 林泰乐
Original assignee: Individual
Current assignee: Shenzhen Lilin Zhigan Technology Co ltd
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2020-12-01
Anticipated expiration: 2039-05-29
Also published as: CN112013769B

Abstract

The invention discloses a signal sensing device for a displacement sensor and an application method thereof, wherein the signal sensing device at least comprises: the two optical head assemblies are marked as a first optical head assembly and a second optical head assembly, the relative displacement measurement code track and the positioning code track are both formed on the information storage medium, the first optical head assembly is used for reading a first electric signal generated by a signal structure on the relative displacement measurement code track when the relative displacement measurement code track moves along the arrangement direction of the bulges and the pits, and the second optical head assembly is used for reading a second electric signal generated by the signal structure on the positioning code track when the positioning code track moves along the arrangement direction of the reference points.

Description

Signal sensing device for displacement sensor and application method thereof

Technical Field

The present invention relates to the field of displacement measurement technologies, and in particular, to a signal sensing device for a displacement sensor and a method for reading a signal on an information storage medium of a displacement sensor.

Background

The displacement sensor can be classified into a grating, a magnetic grating, a capacitive grating, a ball grid, an induction synchronizer, a time grating and the like according to the applied technical principle. Among them, in displacement measurement, gratings are most widely used, especially in medium and high end grating sensors. This is because the sampling frequency, resolution, accuracy and magnetic field immunity of the grating-type sensor are not comparable to those of other displacement sensors.

The light source, the mask grating, the moving grating ruler and the photoelectric sensor which are included in the middle-high end grating sensor have high requirements on the installation precision, so that the middle-high end grating sensor can achieve high-precision measurement. However, the grating of the medium-high end grating sensor has high precision manufacturing difficulty and low yield, the system assembly precision requirement is high, and the problem of increased production cost is caused, so that the medium-high end grating sensor is expensive.

Therefore, it is necessary to provide a new technical solution to achieve accurate measurement of displacement.

Disclosure of Invention

An object of the present invention is to provide a new solution for a signal sensing device for a displacement sensor.

According to a first aspect of the present invention, there is provided a signal sensing apparatus for a displacement sensor, comprising at least two optical pickup units, denoted as a first optical pickup unit and a second optical pickup unit, wherein a relative displacement measurement track and a positioning track are both tracks formed on an information storage medium, the relative displacement measurement track includes protrusions and pits which are continuously and alternately arranged uniformly, the positioning track includes at least one reference point which represents a unique position, wherein first signal structures constituting the respective reference points are pits, intervals between the pits of the first signal structures of the respective reference points are the same, and the number of the pits forming the respective reference points is sequentially increased or decreased,

the first optical head assembly is used for reading a first electric signal generated by a signal structure on the relative displacement measuring code track when the relative displacement measuring code track moves along the arrangement direction of the bulges and the pits,

the second optical head assembly is used for reading a second electric signal generated by a signal structure on the positioning code track when the positioning code track moves along the arrangement direction of the reference points.

Alternatively, the absolute displacement measurement code track is a code track formed on the information storage medium, the absolute displacement measurement code track including protrusions and pits arranged according to a Gray code encoding,

the first optical pick-up assembly is further used for reading a third electric signal generated by the signal structure on the absolute displacement measuring code track along a direction perpendicular to the arrangement direction of the bulges and the pits on the relative displacement measuring code track when the information storage medium is static relative to the first optical pick-up assembly.

Optionally, the signal sensing apparatus further comprises a third head assembly,

the third optical head assembly is used for reading a fourth electric signal generated by a signal structure on the relative displacement measuring code track when the relative displacement measuring code track moves along the arrangement direction of the bulges and the pits,

the mounting positions of the first optical head assembly and the third optical head assembly satisfy:

the first electrical signal determined by the first optical head assembly and the fourth electrical signal determined by the third optical head assembly are out of phase by a non-integer multiple of one-half of a period of the potential signal.

Optionally, when the information storage medium is used for angular displacement measurement, the signal sensing apparatus further comprises a third head assembly,

the mounting positions of the first head assembly and the third head assembly are 180 degrees apart.

Optionally, the optical head assembly comprises a laser transmitter, an optical path component and a laser sensor, wherein,

the light path component is used for irradiating the laser beam emitted by the laser emitter on a code channel formed on the information storage medium and emitting the laser beam reflected by the code channel to the laser sensor.

Optionally, the optical path components in the optical head assembly include a beam splitter, a mirror, a focusing objective lens, wherein,

the position of the focusing objective lens can be adjusted so that the optical focusing center of the focusing objective lens is aligned on the relative displacement measuring track,

the position of the focusing objective lens may be adjusted so that the optical focusing center of the focusing objective lens is moved along the arrangement direction of the lands and pits on the relative displacement measuring track,

the position of the focusing objective lens can be adjusted so that the optical focusing center of the focusing objective lens is moved to scan along the direction perpendicular to the arrangement direction of the projections and the pits on the relative displacement measuring track.

Optionally, a piezo-ceramic component is provided in the optical head assembly,

the piezoelectric ceramic component is used for generating expansion deformation when voltage is applied to drive the focusing objective lens to generate displacement along the arrangement direction of the bulges and the pits on the relative displacement measuring code track, so that the phase difference between the first electric signal generated by the first optical head component and the fourth electric signal generated by the third optical head component is a non-integral multiple of one half of one electric signal period.

Optionally, the laser sensor is a four-quadrant distributed photoelectric sensor, and generates four electrical signals in total, which are recorded as an electrical signal a, an electrical signal b, an electrical signal c, and an electrical signal d, where the sum of the four electrical signals is used to generate an electrical signal corresponding to each code channel, and a difference between an electrical signal result obtained by adding the electrical signal a and the electrical signal c and an electrical signal result obtained by adding the electrical signal b and the electrical signal d is used to correct laser focusing.

Optionally, the signal sensing device further includes two torquers, namely a first torquer and a second torquer, where the first torquer is used to drive the focusing objective lens in the optical path component to move along the optical axis direction of the focusing objective lens, so as to ensure that the laser beam is automatically focused on the surface of the protrusion or the pit of each track; the second moment device is used for driving the focusing objective lens so as to control the laser beam to read a third electric signal generated by a signal structure on the absolute displacement measuring code track along a direction perpendicular to the arrangement direction of the bulges and the pits on the relative displacement measuring code track.

Optionally, the displacement sensor is any one of a linear displacement sensor and an angular displacement sensor.

According to a second aspect of the present invention, there is provided a method of reading a signal on an information storage medium for a displacement sensor,

the information storage medium is formed with a relative displacement measuring code track and a positioning code track,

the relative displacement measuring code track comprises bulges and pits which are continuously, alternately and uniformly arranged, the positioning code track comprises at least one reference point which represents a unique position, wherein the first signal structures forming each reference point are pits, the intervals among the pits of the first signal structures of each reference point are the same, and the number of the pits forming each reference point is sequentially increased or decreased,

the method comprises the following steps:

controlling a first head assembly to emit a first laser beam and a second head assembly to emit a second laser beam while the information storage medium is moved;

determining relative displacement information according to a first electric signal generated by laser reflected by the bumps and pits on the relative displacement measuring code track received by the first optical head assembly, and determining current position information according to a second electric signal generated by laser reflected by the bumps and pits on the positioning code track received by the second optical head assembly;

determining motion direction information of the information storage medium according to the second electric signal;

determining current actual position information of the information storage medium according to the relative displacement amount information determined by the first electric signal, current position information determined by the second electric signal and motion direction information of the information storage medium determined by the second electric signal.

Optionally, the information storage medium further has an absolute displacement measurement code track formed thereon, the absolute displacement measurement code track including protrusions and pits arranged according to a gray code,

the method further comprises the following steps:

when the information storage medium is static relative to the first optical head assembly, controlling the first optical head assembly to emit a first laser beam, and reading a third electric signal generated by a signal structure on the absolute displacement measurement code track along a direction perpendicular to the arrangement direction of the bulges and the pits on the relative displacement measurement code track;

determining absolute displacement information from the third electrical signal;

and after the information storage medium moves, calculating and determining the current actual position information of the information storage medium according to the relative displacement information determined by the first electric signal and the absolute displacement information determined by the third electric signal.

Optionally, the method further comprises:

controlling a third optical head assembly to emit a third laser beam when the information storage medium is moved;

generating a fourth electrical signal according to the laser reflected by the bumps and pits on the relative displacement measuring track received by the third optical head assembly;

determining a moving direction of the information storage medium according to a phase difference of the first electrical signal and the fourth electrical signal.

According to one embodiment of the present disclosure, the actual position information and the direction of motion of the signal-carrying body arrangement may be determined from the first electrical signal and the second electrical signal.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic diagram of a signal carrier apparatus for linear displacement measurement according to one embodiment of the present invention.

Fig. 2 is a schematic diagram of a signal carrier apparatus for angular displacement measurement according to one embodiment of the present invention.

Fig. 3 is a schematic diagram of a signal carrier apparatus for linear displacement measurement according to another embodiment of the present invention.

Fig. 4 is a schematic diagram of a signal carrier apparatus for angular displacement measurement according to another embodiment of the present invention.

Fig. 5 is a schematic diagram of a signal carrier apparatus for linear displacement measurement according to another embodiment of the present invention.

Fig. 6 is a schematic diagram of a signal carrier apparatus for angular displacement measurement according to another embodiment of the present invention.

Fig. 7 is a schematic diagram of a signal carrier apparatus for linear displacement measurement according to another embodiment of the present invention.

Fig. 8a shows a schematic diagram of a pattern corresponding to gray code encoding.

Fig. 8b shows a schematic diagram of another pattern corresponding to gray code.

Fig. 9 shows a schematic diagram of a signal carrier apparatus for linear displacement measurement according to another embodiment of the present invention.

Fig. 10 shows a schematic diagram of a signal carrier apparatus for angular displacement measurement according to another embodiment of the present invention.

Fig. 11 is a schematic diagram of a signal carrier apparatus according to yet another embodiment of the present invention.

Fig. 12 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to an embodiment of the present invention.

Fig. 13 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to one embodiment of the present invention.

Fig. 14 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to another embodiment of the present invention.

Fig. 15 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to another embodiment of the present invention.

Fig. 16 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to another embodiment of the present invention.

Fig. 17 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to another embodiment of the present invention.

Fig. 18 is a schematic structural view of an optical head assembly according to an embodiment of the present invention.

Fig. 19 is a schematic structural view of an optical head assembly according to an embodiment of the present invention.

Fig. 20 is a schematic structural diagram of a displacement measurement system according to an embodiment of the present invention.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

< Signal Carrier apparatus >

One embodiment of the present invention provides a signal carrier apparatus for displacement measurement. The signal carrier apparatus comprises: an information storage medium and a displacement measuring code track formed on the information storage medium. The displacement measuring code channel at least comprises a relative displacement measuring code channel. The relative displacement measuring code track comprises bulges and pits which are continuously, alternately and uniformly arranged. The information storage medium may be a photo-induced storage medium. For example, the optically readable storage medium may comprise any of CD (Compact Disc), VCD (video Compact Disc), MO (Magnet optical), DVD (digital Versatile Disc), EVD (enhanced Disc), HD-DVD (high Definition DVD), and BD (Blu-ray Disc).

The material of the photo-induced storage medium is a polymer material (e.g., Polycarbonate (PC)) or a glass material.

The projection on the photo-induced storage medium can be formed by vacuum metal coating, specifically, the projection is formed by deposition, accumulation and gasification at the position where the projection is formed. Pits in the photo-induced storage medium may be formed by means of indentations.

The surface of the convex and concave pits on the optical storage medium is provided with light reflecting performance through surface metallization.

Width w of pit: w is more than or equal to 0.1 mu m and less than or equal to 100 mu m, and the depth h of the pit is as follows: h is not less than 50nm and not more than 200nm, and the length l of the pit is as follows: l is more than or equal to 0.1 mu m and less than or equal to 1000 mu m.

The signal carrier device provided by the embodiment of the invention can be used for measuring linear displacement and angular displacement.

When the signal carrier device is used for linear displacement measurement, the projections and the pits on the relative displacement measurement code track and the positioning code track are arranged along a straight line on the information storage medium. When the signal carrier device is used for angular displacement measurement, the projections and the pits on the relative displacement measurement code track and the positioning code track are arranged along the circumference on the information storage medium.

Referring to fig. 1, the signal carrier apparatus includes an information storage medium 110 and a displacement measuring track 120 formed on the information storage medium 110. The code channel 120 includes a code channel 121 for measuring relative displacement. The relative displacement measuring track 121 includes protrusions and pits which are continuously and alternately arranged. Wherein white areas in fig. 1 represent protrusions and black areas represent pits.

The y-direction shown in fig. 1 is the direction of motion of the signal carrier means. The projections and the pits on the relative displacement measurement code track 121 are arranged along the y direction.

Referring to fig. 1, based on the signal carrier apparatus for linear displacement measurement, along the arrangement direction of the bumps and the pits of the relative displacement measurement track 121, the distance value a between two adjacent pits is equal to the width value b of one pit.

Fig. 2 is a schematic diagram of a signal carrier apparatus for angular displacement measurement according to one embodiment of the present invention. Referring to fig. 2, the signal carrier apparatus includes an information storage medium 210 and a displacement measuring code track 220 formed on the information storage medium 210. The code channel 220 includes a code channel 221 for measuring relative displacement. The relative displacement measurement code track 221 includes protrusions and pits that are continuously, alternately, and uniformly arranged. Wherein the white areas in fig. 2 represent protrusions and the black areas represent pits.

The theta direction shown in fig. 2 is the direction of rotation of the signal carrier means. The projections and the pits on the relative displacement measurement code track 221 are arranged in the θ direction.

Referring to fig. 2, based on the signal carrier apparatus for angular displacement measurement, an included angle α formed by two adjacent pits and the center of the circumference in which the relative displacement measurement code is arranged is equal to an included angle β formed by one pit and the center of the circumference in which the relative displacement measurement code is arranged.

In one embodiment of the present invention, the displacement measuring code channel includes a positioning code channel in addition to the relative displacement measuring code channel.

The location code channel includes at least one reference point representing a unique location. The first signal structures forming the reference points are pits, the intervals among the pits of the first signal structures of the reference points are the same, and the number of the pits forming the reference points is sequentially increased or decreased.

When the signal carrier device is used for linear displacement measurement, the interval between the pits of the first signal structure of each reference point refers to the distance value between the pits of the first signal structures of two adjacent reference points along the arrangement direction of the bulges and the pits on the relative displacement measurement code track.

When the signal carrier device is used for measuring angular displacement, the interval between the pits of the first signal structure of each reference point is an included angle formed by the center of the pit of the first signal structure of two adjacent reference points and the center of the circle arranged relative to the displacement measuring code track.

In one embodiment, the pit of the first signal structure forming each reference point on the positioning code track may or may not be aligned with a pit on the relative displacement measurement code track.

When the pits of the first signal structure forming each reference point on the positioning code track are aligned with one pit on the relative displacement measurement code track and the signal carrying body device is used for linear displacement measurement, the alignment refers to alignment along the arrangement direction of the bulges and the pits which are vertical to the displacement measurement code track. When the signal carrier device is used for angular displacement measurement, the alignment refers to alignment along the radial direction of the circumference of the displacement measurement track.

In one example, the location code track includes only one reference point, designated as a zero reference point. The reference point may represent a unique location.

Referring to fig. 3, the signal carrier apparatus includes an information storage medium 310 and a displacement measuring code track 320 formed on the information storage medium 310.

The code channel 320 includes a code channel 321 and a code channel 322.

The location code channel 322 includes a reference point that may represent a unique location.

The y-direction shown in fig. 3 is the direction of motion of the signal carrier means. The projections and the pits on the relative displacement measurement code track 321 and the positioning code track 322 are arranged along the y direction.

Referring to fig. 4, the signal carrier apparatus includes an information storage medium 410 and a displacement measuring code track 420 formed on the information storage medium 410.

The code channel 420 includes a relative displacement measurement code channel 421 and a positioning code channel 422.

The location code channel 422 includes a reference point that may represent a unique location.

The theta direction shown in fig. 4 is the direction of rotation of the signal carrier means. The projections and depressions on the relative displacement measurement track 421 and the positioning track 422 are arranged in the θ direction.

When the positioning code channel of the signal carrier device only includes the reference point representing the zero position, the position of the reference point of the zero position needs to be determined firstly in the process of measuring the displacement of the signal carrier device. In the process of determining the position of the zero-position reference point, if the distance between the currently read position of the signal sensing device and the position of the zero-position reference point is long, at this time, the signal carrying body device needs to move for a long distance or rotate for a large angle, so that the signal sensing device determines the position of the zero-position reference point according to an electric signal generated when the signal sensing device reads the relative displacement measurement code channel and the positioning code channel, and thus, the current absolute position is not favorably and quickly determined.

In order to be able to quickly determine the current absolute position from the relative displacement measurement track and the positioning track, the positioning track comprises a plurality of reference points representing a unique position. The first signal structures forming each reference point are pits, and the intervals between the pits of the first signal structures of each reference point are the same, and the number of the pits forming each reference point is sequentially increased or decreased.

When the positioning code track includes a plurality of reference points representing different positioning, a linear displacement measurement is taken as an example, based on the fact that the distance value between two adjacent pits forming each reference point is equal to the width value of one pit, or based on the fact that the distance value between two adjacent pits forming each reference point is not equal to the width value of one pit.

When the positioning code channel comprises a plurality of reference points representing different positioning, taking angular displacement measurement as an example, an included angle formed by two adjacent pits forming each reference point and the center of the circumference in which the relative displacement measurement code channels are arranged is equal to an included angle formed by one pit and the center of the circumference in which the relative displacement measurement code channels are arranged, or an included angle formed by two adjacent pits forming each reference point and the center of the circumference in which the relative displacement measurement code channels are arranged is not equal to an included angle formed by one pit and the center of the circumference in which the relative displacement measurement code channels are arranged.

Referring to fig. 5, the signal carrier apparatus includes an information storage medium 510 and a displacement measuring code track 520 formed on the information storage medium 510. The code channel 520 includes a relative displacement measurement code channel 521 and a positioning code channel 522.

The track 522 includes a plurality of reference points representing a unique position, and each reference point includes a distance value between two adjacent pits equal to a width value of one pit.

The y-direction shown in fig. 5 is the direction of motion of the signal carrier means. The projections and pits on the relative displacement measurement track 521 and the positioning track 522 are arranged along the y direction.

Referring to fig. 5, the signal structure forming the first reference point comprises a pit, and the pit is aligned with a pit on the relative displacement measuring track.

The signal structure constituting the second reference point comprises two pits whose distance between them has a value equal to the width of one pit. The second reference point comprises a first pit and the first reference point comprises a pit with a spacing d in left-to-right order. The second reference point comprises the first pit aligned with a pit on the relative displacement measuring track.

The signal structure constituting the third reference point comprises three pits, and the distance between two adjacent pits has a value equal to the width of one pit. The interval between the first pit included in the third reference point and the first pit included in the second reference point is also d in order from left to right. The third reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

The signal structure constituting the fourth reference point comprises four pits, and the distance between two adjacent pits has a value equal to the width of one pit. The spacing between the first pit comprised by the fourth reference point and the first pit comprised by the third reference point is also d, in left to right order. The fourth reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

When the signal carrier device shown in fig. 5 does not start to move linearly, the signal sensing device for reading the relative displacement measurement code track is located above the pit a, and the signal sensing device for reading the positioning code track is located above a certain bump between the first reference point (zero reference point) and the second reference point. After the signal carrier device starts to move, when the signal sensing device for reading the relative displacement measurement code channel and the signal sensing device for reading the positioning code channel both generate the same electric signal, the current position is determined to be the position of one reference point, and the number of the electric signals corresponding to the reference point read by the signal sensing device for reading the positioning code channel is two, so that the reference point can be determined to represent the second reference point from the zero reference point.

Referring to fig. 6, the signal carrier apparatus includes an information storage medium 610 and a displacement measuring track 620 formed on the information storage medium 610. The code channel 620 includes a relative displacement measurement code channel 621 and a positioning code channel 622.

The positioning track 1122 includes a plurality of reference points representing a unique position, and each of the reference points includes two adjacent pits forming an angle with the center of the circumference on which the relative displacement measuring track is arranged, which is equal to an angle formed by one pit with the center of the circumference on which the relative displacement measuring track is arranged.

The theta direction shown in fig. 6 is the direction of rotation of the signal carrier means. The projections and depressions on the relative displacement measurement track 621 and the positioning track 622 are arranged in the θ direction.

Referring to fig. 6, the positioning track 622 includes 6 reference points.

The signal structure forming the first reference point comprises a pit, and the pit is aligned with a pit on the relative displacement measuring track.

The signal structure forming the second reference point includes two pits, and an included angle formed by the two pits and the center of the circumference in which the relative displacement measurement code tracks are arranged is equal to an included angle formed by one pit and the center of the circumference in which the relative displacement measurement code tracks are arranged. According to the anticlockwise direction, the included angle formed by the center of the first pit included by the second reference point and the center of the pit included by the first reference point and the center of the circle where the positioning code track is arranged is alpha. The second reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

The signal structure forming the third reference point comprises three pits, and an included angle formed by two adjacent pits and the center of the circumference in which the relative displacement measurement code channels are arranged is equal to an included angle formed by one pit and the center of the circumference in which the relative displacement measurement code channels are arranged. According to the anticlockwise direction, the included angle formed by the center of the first pit included by the third reference point and the center of the first pit included by the second reference point and the center of the circle where the positioning code tracks are arranged is also alpha. The third reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

The signal structure forming the fourth reference point comprises four pits, and an included angle formed by two adjacent pits and the center of the circumference in which the relative displacement measurement code channels are arranged is equal to an included angle formed by one pit and the center of the circumference in which the relative displacement measurement code channels are arranged. According to the anticlockwise direction, the included angle formed by the center of the first pit included by the fourth reference point and the center of the first pit included by the third reference point and the center of the circle where the positioning code track is arranged is also alpha. The fourth reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

The fifth reference point and the sixth reference point have the characteristics of the four reference points, and are not described in detail herein.

When the signal carrier device shown in fig. 6 does not start to rotate, the signal sensing device for reading the relative displacement measurement code track is located above the pit b, and the signal sensing device for reading the positioning code track is located above a certain bump between the first reference point (zero reference point) and the second reference point. When the signal carrier device starts to rotate, when the signal sensing device for reading the relative displacement measurement code channel and the signal sensing device for reading the positioning code channel both generate the same electric signal, the current position is determined to be the position of one reference point, and the number of the electric signals corresponding to the reference point read by the signal sensing device for reading the positioning code channel is two, so that the reference point can be determined to represent the second reference point from the zero reference point.

Referring to fig. 7, the signal carrier apparatus includes an information storage medium 710 and a displacement measuring track 720 formed on the information storage medium 710. The code channel 720 includes a code channel 721 and a code channel 722.

The track 722 includes a plurality of reference points representing a unique position, and the pits of each reference point are arranged at equal intervals.

The y-direction shown in fig. 7 is the direction of motion of the signal carrier means. The projections and pits on the relative displacement measurement track 721 and the positioning track 722 are arranged in the y direction.

Referring to fig. 7, the signal structure constituting the first reference point includes a pit, and the pit is aligned with a pit on the relative displacement measurement code track.

The signal structure constituting the second reference point comprises two pits, the distance between which has a value greater than the width of one pit. The second reference point comprises a first pit and the first reference point comprises a pit with a spacing d in left-to-right order. The second reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

The signal structure constituting the third reference point comprises three pits, and the distance between two adjacent pits is greater than the width of one pit. The interval between the first pit included in the third reference point and the first pit included in the second reference point is also d in order from left to right. The third reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

The signal structure constituting the fourth reference point comprises four pits, and the distance between two adjacent pits is greater than the width of one pit. The spacing between the first pit comprised by the fourth reference point and the first pit comprised by the third reference point is also d, in left to right order. The fourth reference point comprises a first pit aligned with a pit on the relative displacement measuring track.

The number of reference points included in the positioning code track shown in fig. 5, 6 and 7 is only an example, and does not limit the present invention.

When the information storage medium is formed with a relative displacement measuring code track and a positioning code track, it can be used for measuring relative displacement.

Taking the signal carrier device shown in fig. 5 as an example, when the signal carrier device starts moving to the left, the signal sensing device for reading the relative displacement measurement code track is located above the eleventh pit, and the signal sensing device for reading the positioning code track is located above the first pit representing the second reference point. At this time, when the signal sensing device reading the relative displacement code channel and the signal sensing device reading the positioning code channel both generate a same electric signal, the current position is determined to be the position of one reference point, and the number of the electric signals corresponding to the reference point read by the signal sensing device reading the positioning code channel is two, so that the reference point can be determined to represent a second reference point from the zero reference point. Therefore, the electric signal generated by the signal sensing device for reading the relative displacement measurement code channel can determine the relative displacement, and the electric signal generated by the signal sensing device for reading the positioning code channel can determine the current position information. The actual position information in the motion process can be determined according to the relative displacement and the current position information.

In one embodiment of the present invention, the displacement measuring code channel includes an absolute displacement measuring code channel in addition to the relative displacement measuring code channel.

The absolute displacement measuring code track comprises bulges and pits which are coded and arranged according to a binary coding rule.

The binary encoding may be gray code encoding. The patterns corresponding to the Gray codes are in pyramid symmetry.

Fig. 8a shows a schematic diagram of a corresponding pattern for gray code encoding for linear displacement measurement. Fig. 8b shows a schematic diagram of a corresponding further pattern of gray codes for angular displacement measurement.

Referring to fig. 8a, the lowest bit varies from 1 (0 to 2) to a large, one 1, one 0, and one more 1, one 0, where black areas represent 1 and white areas represent 0; the second low level changes from 2 (the power of 1 of 2) to large, two 1 s are continuous, two 0 s are continuous, and two 1 s are continuous; the third lower level starts from 4(2 to the power of 2), and is four 1 in succession, four 0 in succession, and four 1 in succession; the fourth low order is from 8 (power 3 of 2), eight 1's in succession, eight 0's in succession, eight 1's in succession, and so on.

When the information storage medium is formed with a relative displacement measurement code track and an absolute displacement measurement code track, it can be used for the measurement of absolute displacement.

Referring to fig. 9, the signal carrier apparatus includes an information storage medium 910 and a displacement measuring code track 920 formed on the information storage medium 910. The code channel 920 includes a code channel 921 for measuring relative displacement and a code channel 922 for measuring absolute displacement.

The absolute displacement measurement code channel 922 includes protrusions and recesses formed in an X-direction according to gray code encoding. The absolute displacement measurement code channel 922 shown in FIG. 9 includes multiple code channels. An isolated code channel is arranged between adjacent code channels formed by the bulges and the pits which are arranged according to the Gray code. The isolation code channels are all composed of bulges. The width of the isolated code channel can be set arbitrarily, for example, the width of the isolated code channel is equal to the width of the code channel formed by the protrusions and the pits arranged according to the gray code.

Referring to fig. 9, the y-direction of the signal carrier means is shown in fig. 9 as the direction of motion of the signal carrier means, and the x-direction is perpendicular to the direction of motion of the signal carrier means. The projections and the pits on the relative displacement measurement code track 921 are arranged along the y direction. The bumps and pits on the absolute displacement measurement code tracks 922 are arranged along the x direction. This arrangement is shown schematically in fig. 8a for a gray code arrangement. And no isolated code channel exists between adjacent code channels formed by the bulges and the pits which are arranged according to the Gray code.

Referring to fig. 10, the signal carrier apparatus includes an information storage medium 1010 and a displacement measuring track 1020 formed on the information storage medium 1010. The code channel 1020 includes a code channel 1021 and a code channel 1022.

The absolute displacement measurement code track 1022 includes protrusions and pits arranged according to gray code.

The absolute displacement measurement code track 1022 shown in FIG. 10 includes a plurality of code tracks. An isolated code channel is arranged between adjacent code channels formed by the bulges and the pits which are arranged according to the Gray code. The isolation code channels are all composed of bulges. The width of the isolated code channel can be set arbitrarily, for example, the width of the isolated code channel is equal to the width of the code channel formed by the protrusions and the pits arranged according to the gray code.

Referring to fig. 10, the theta direction shown in fig. 10 is the rotational direction of the signal carrier means and the R direction is the axial direction of the signal carrier means. The projections and the depressions on the relative displacement measurement track 1021 are arranged in the θ direction. The bumps and pits on the absolute displacement measurement code track 1022 are arranged along the R direction. This arrangement is illustrated schematically in the gray code arrangement shown in fig. 8 b.

And no isolated code channel exists between adjacent code channels formed by the bulges and the pits which are arranged according to the Gray code.

In the signal carrier device according to any of the above embodiments, the shape of the pits included in the displacement measuring code formed on the information storage medium is not limited to a linear shape, and may also be a circular shape.

Referring to fig. 11, the signal carrier apparatus includes an information storage medium 1110 and a displacement measuring code track 1120 formed on the information storage medium 1110. The code track 1120 includes a code track 1121. The relative displacement measurement code 1121 includes a circular pit.

The signal carrier device provided by the embodiment of the invention forms a relative displacement measurement code channel on an information storage medium, wherein the relative displacement measurement code channel comprises a readable alternating signal consisting of a bump and a pit, and displacement measurement is realized by reading the alternating signal of the relative displacement measurement code channel.

< Signal sensing device >

One embodiment of the present invention provides a signal sensing apparatus for a displacement sensor, comprising at least two optical head assemblies, referred to as a first optical head assembly and a second optical head assembly.

The relative displacement measuring code track and the positioning code track are both code tracks formed on the information storage medium, and the relative displacement measuring code track comprises bulges and pits which are continuously, alternately and uniformly arranged.

The positioning code track comprises at least one reference point representing different positioning, wherein the first signal structures forming each reference point are pits, the intervals between the pits of the first signal structures of each reference point are the same, and the number of the pits forming each reference point is increased or decreased in sequence.

The first optical head assembly is used for reading a first electric signal generated by a signal structure on the relative displacement measuring code track when the relative displacement measuring code track moves along the arrangement direction of the bulges and the pits.

The relative displacement amount information can be determined from the first electrical signal.

Current position information may be determined from the second electrical signal, and movement direction information of the information storage medium may be determined.

The current actual position information of the information storage medium can be determined according to the relative displacement amount information determined by the first electric signal, the current position information determined by the second electric signal and the motion direction information of the information storage medium determined by the second electric signal.

The direction of movement of the information storage medium may also be determined from the second electrical signal. That is, when the positioning code track moves along the arrangement direction of the reference points, the signal sensing device can also determine the moving direction of the information storage medium according to the positioning represented by the reference points which are sequentially read by the signal sensing device.

The signal carrier device shown in fig. 12 is used for the measurement of linear displacement.

Referring to fig. 12, the signal sensing apparatus includes at least two optical head assemblies, a first optical head assembly 1210 and a second optical head assembly 1220.

The signal carrier means comprises an information storage medium. The relative displacement measurement code track 1230 and the positioning code track 1240 are both code tracks formed on the information storage medium.

The first optical head assembly 1210 is used for reading a first electrical signal generated by a signal structure on the relative displacement measurement code track 1230 moving along the direction of the arrangement of the protrusions and the pits (i.e., along the y direction shown in fig. 12).

The second optical pick-up assembly 1220 is used for reading a second electrical signal generated by the signal structure on the positioning track when the positioning track moves along the arrangement direction of the reference points (i.e. along the y direction shown in fig. 12).

Referring to fig. 12, when the signal carrier device does not start to move linearly, the first optical pick-up assembly 1210 for reading the relative displacement measuring track is located above the pit a, and the second optical pick-up assembly 1220 for reading the positioning track is located above a bump between the first reference point (zero reference point) and the second reference point.

After the signal carrier device starts to move, when the first optical pick-up assembly 1210 for reading the relative displacement measurement code track and the second optical pick-up assembly 1220 for reading the positioning code track both generate a same electrical signal, the current position is determined to be the position of a reference point, and the number of the electrical signals corresponding to the reference point read by the second optical pick-up assembly 1220 for reading the positioning code track is two, so that the reference point can be determined to represent a second reference point from the zero reference point.

When the signal carrier device continues to move, the second optical pick-up assembly 1220 reading the positioning code channel reads three electrical signals corresponding to the next reference point, so that it can be determined that the signal carrier device moves along the positive y direction.

Fig. 13 shows a signal carrier device for angular displacement measurement.

Referring to fig. 13, the signal sensing apparatus includes at least two head assemblies, a first head assembly 1310 and a second head assembly 1320.

The signal carrier means comprises an information storage medium. The relative displacement measurement code track 1330 and the positioning code track 1340 are both code tracks formed on the information storage medium.

The first optical head assembly 1310 is used for reading a first electrical signal generated by a signal structure on the relative displacement measuring track 1330 when the relative displacement measuring track is rotated along the arrangement direction of the protrusions and the pits (i.e. along the θ direction shown in fig. 13).

The second optical head assembly 1320 is used for reading a second electrical signal generated by the signal structure on the positioning track when the positioning track rotates along the arrangement direction of the reference points (i.e. along the θ direction shown in fig. 13).

Referring to fig. 13, when the signal carrier device does not start rotating, the first optical pick-up assembly 1310 for reading the relative displacement measurement code track is located above the pit b, and the second optical pick-up assembly 1320 for reading the positioning code track is located above a bump between the first reference point (zero reference point) and the second reference point.

When the signal carrier starts to rotate, when the first optical pick-up assembly 1310 for reading the relative displacement measurement code track and the second optical pick-up assembly 1320 for reading the positioning code track both generate a same electrical signal, the current position is determined to be the position of a reference point, and the number of the electrical signals corresponding to the reference point read by the second optical pick-up assembly 1320 for reading the positioning code track is two, so that the reference point can be determined to represent the second reference point from the zero reference point.

When the signal carrier device continues to move, the second pick-up unit 1320 reading the positioning track reads three electrical signals corresponding to the next reference point, so as to determine that the signal carrier device moves along the counterclockwise direction.

An embodiment of the present invention provides the information storage medium further comprising an absolute displacement measurement. The absolute displacement measuring code track includes projections and pits arranged in accordance with a gray code.

The first optical pick-up assembly is further used for reading a third electric signal generated by the signal structure on the absolute displacement measuring code track along a direction perpendicular to the arrangement direction of the bumps and the pits on the relative displacement measuring code track when the information storage medium is stationary relative to the first optical pick-up assembly. Absolute displacement information of the current position can thus be determined from the third electrical signal.

Fig. 14 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to an embodiment of the present invention.

Fig. 14 shows a signal carrier device for measurement of linear displacement.

As shown in fig. 14, the signal carrier means comprises an information storage medium. The relative displacement measurement code track 1430 and the absolute displacement measurement code track 1440 are both code tracks formed on the information storage medium.

The first optical head assembly 1410 is configured to read a first electrical signal generated by a signal structure on the relative displacement measurement track 1430 when the relative displacement measurement track is moved along the direction of the land and pit arrangement (i.e., along the y-direction shown in fig. 14).

The first head assembly 1410 is further configured to read a third electrical signal generated by the signal structure on the absolute displacement measurement track along a direction perpendicular to the arrangement direction of the lands and pits on the relative displacement measurement track (i.e., along the x-direction shown in fig. 14) when the information storage medium is stationary with respect to the first head assembly 1410. Absolute displacement information of the current position may be determined from the third electrical signal.

Fig. 15 is a schematic structural diagram illustrating relative positions of a signal sensing means and a signal carrier means for a displacement sensor according to one embodiment of the present invention.

Fig. 15 shows a signal carrier device for angular displacement measurement.

As shown in fig. 15, the signal carrier means comprises an information storage medium. The relative displacement measurement code track 1530 and the absolute displacement measurement code track 1540 are both code tracks formed on the information storage medium.

The first head unit 1510 is configured to read a first electrical signal generated by a signal structure on the relative displacement measurement track 1530 when the relative displacement measurement track 1530 rotates along the arrangement direction of the bumps and the pits (i.e., along the θ direction shown in fig. 15).

The first head assembly 1510 is further configured to read a third electrical signal generated by a signal structure on the absolute displacement measurement track in a direction perpendicular to the arrangement direction of the lands and pits on the relative displacement measurement track (i.e., in the R direction shown in fig. 15) when the information storage medium is stationary with respect to the first head assembly 1510. Absolute displacement information of the current position may be determined from the third electrical signal.

In one embodiment, the signal sensing apparatus further comprises a third head assembly. The third optical head assembly is used for reading a fourth electric signal generated by a signal structure on the relative displacement measuring code track when the relative displacement measuring code track moves along the arrangement direction of the bulges and the pits. The mounting positions of the first optical head assembly and the third optical head assembly satisfy: the first electrical signal determined by the first optical head assembly and the fourth electrical signal determined by the third optical head assembly are out of phase by a non-integer multiple of one-half of the period of the potential signal.

Referring to fig. 16, the signal sensing apparatus further includes a third head assembly 1250.

The third optical head assembly 1250 is used for reading a fourth electrical signal generated by a signal structure on the relative displacement measuring code track 1230 when the relative displacement measuring code track is moved along the arrangement direction of the protrusions and the pits (i.e., along the y direction shown in fig. 16).

The mounting positions of the first head assembly 1210 and the third head assembly 1250 are such that: the first electrical signal determined by the first optical head assembly and the fourth electrical signal determined by the third optical head assembly are out of phase by a non-integer multiple of one-half of the period of the potential signal. This allows the direction of movement of the signal carrier means to be determined.

Taking the case where the phase difference between the first electric signal determined by the first optical head assembly and the fourth electric signal determined by the third optical head assembly is one-fourth of the period of one electric potential signal, the length of one electric signal period is set to be p. When the signal carrier device is moved in the positive y direction shown in fig. 16, the rising edge of the fourth electrical signal lags the rising edge of the first electrical signal by 1/4 p. When the signal carrier device moves in the negative direction of y shown in fig. 16, the rising edge of the fourth electrical signal lags the rising edge of the first electrical signal by 3/4 p. Thus, the direction of motion of the signal carrier means is determined in dependence on the length of the hysteresis period of the first electrical signal and the fourth electrical signal. In addition, the first electric signal and the fourth electric signal can realize mutual check and mutual error correction, and the reliability and the precision of measurement are improved.

In one embodiment, the signal sensing apparatus further comprises a third head assembly 1350, according to fig. 17, when the information storage medium is used for angular displacement measurement.

The third optical head assembly 1350 is used for reading the fourth electrical signal generated by the signal structure on the relative-displacement measuring track 1310 when the relative-displacement measuring track 1310 rotates along the direction of the land and pit arrangement (i.e., along the θ direction shown in fig. 17).

The mounting positions of the first pick-up assembly 1310 and the third pick-up assembly 1350 are different by 180 degrees, so that the first electric signal and the fourth electric signal can form differential performance, and the measurement error, particularly the error caused by mounting eccentricity, is reduced.

Each optical head assembly includes a laser emitter 1810, an optical path system component 1820, and a laser sensor 1830.

The laser emitter 1810 is used to emit a laser beam.

The optical path system member 1820 serves to irradiate a laser beam emitted from the laser emitter 1810 onto a track formed on the information storage medium, and to introduce laser light reflected from the track into the laser sensor 1830.

The laser sensor 1830 is used to determine the generated electrical signal according to the laser light reflected by the code track.

As shown in fig. 18, the optical path system components 1820 include at least a beam splitter 1821, a mirror 1822, and a focusing objective lens. Wherein the focusing objective comprises a first focusing objective 1823 and a second focusing objective 1824.

The beam splitter 1821 is configured to split the laser beam emitted by the laser emitter 1810 and irradiate the laser beam split by the beam splitter onto the mirror 1822.

The mirror 1822 is configured to reflect the laser beam obtained through the beam splitting process, and irradiate the reflected laser beam on the first focusing objective 1823.

The first focusing objective 1823 is used to focus the received laser light onto the track. The bumps and pits on the track can reflect the laser irradiated thereon.

The second focusing objective 1824 is used to focus the laser light reflected by the lands and pits on the track onto the mirror 1822.

The reflecting mirror 1822 is further configured to reflect laser light reflected by the bumps and pits on the track, and irradiate the reflected laser light onto the light beam splitter 1821.

The beam splitter 1821 is further configured to split the reflected laser beam, and irradiate the laser sensor 1830 with a beam of laser beam obtained through the splitting.

The position of the focusing objective lens can be adjusted so that the optical focusing center of the focusing objective lens is aligned on the relative displacement measuring track.

The position of the focusing objective lens can be adjusted so that the optical focusing center of the focusing objective lens is moved in the arrangement direction of the lands and pits on the relative displacement measuring track.

The position of the focusing objective lens is adjusted so that the optical focusing center of the focusing objective lens is moved in the direction of arrangement of the lands and pits on the vertical relative displacement measuring track.

The laser sensor 1830 is a four-quadrant distributed photoelectric sensor, and generates four electrical signals in total, which are denoted as an electrical signal a, an electrical signal b, an electrical signal c, and an electrical signal d, wherein the sum of the four electrical signals is used to generate an electrical signal corresponding to each code channel, and the difference between the electrical signal result obtained by adding the electrical signal a and the electrical signal c and the electrical signal result obtained by adding the electrical signal b and the electrical signal d is used to correct laser focusing.

As shown in FIG. 18, the signal sensing device further includes two torquers, designated as first torquer 1841 and second torquer 1842.

The first moment device 1841 is used to drive the focusing objective lens in the optical path member to move in the direction of its optical axis to ensure that the laser beam is automatically focused on the surface of the convex pits of each track. Specifically, the laser beam is ensured to be automatically focused on the surface of the convex pits of each track along the z-axis direction shown in fig. 18.

The second moment device 1842 is used for driving the focusing objective lens to control the laser beam to read the third electric signal generated by the signal structure on the absolute displacement measuring track along the direction perpendicular to the arrangement direction of the protrusions and pits on the relative displacement measuring track. Specifically, when the information storage medium is used for linear displacement measurement, the laser beam is controlled to read the third electrical signal generated by the signal structure on the absolute displacement measurement track along the x-axis direction shown in fig. 18. When the information storage medium is used for angular displacement measurement, the laser beam is controlled to read a third electrical signal generated by a signal structure on the absolute displacement measurement track in the R direction shown in fig. 18.

In one embodiment, the head assembly is provided with a piezo-ceramic element. The piezoelectric ceramic component is used for generating expansion deformation when voltage is applied to drive the focusing objective lens to generate displacement along the arrangement direction of the bulges and the pits on the relative displacement measurement code track, so that the phase difference of a first electric signal generated by the first optical head component and a fourth electric signal generated by the third optical head component is a non-integral multiple of half of one electric signal period.

Fig. 19 is an exploded view of an optical head assembly according to one embodiment of the present invention.

In this embodiment, the optical path components in the optical head assembly include a beam splitter, a mirror, and a focusing objective lens.

The focusing objectives are all mounted in a first through hole 1911 opened in the first base 1910. The optical center of the focusing objective is aligned with the relative displacement measuring code track.

The first base 1910 is fixed to the second base 1920. The second base 1920 is opened with a second through hole 1921. The axial direction of the second through hole 1921 is parallel to the axial direction of the first through hole 1911.

Referring to fig. 19, the second through hole 1921 is equipped with a piezoceramic component 1930.

The piezoelectric ceramic element 1930 is configured to generate an expansion deformation when a voltage is applied, so as to drive the second base 1920 to generate a displacement along the y-axis direction, and further drive the first base 1910 to generate a displacement along the y-axis, so that the optical center of the focusing objective lens moves along the y-axis. Thus, the optical center of the focusing objective lens moves along the relative displacement measuring code track to adjust the phase difference of the first electric signal and the fourth electric signal, so that the phase difference of the first electric signal and the fourth electric signal is a non-integral multiple of half of one electric signal period.

One embodiment of the present invention provides a method of reading a signal on an information storage medium for a displacement sensor. The information storage medium is formed with a relative displacement measuring code track and a positioning code track. The relative displacement measuring code track comprises bulges and pits which are continuously and alternately and uniformly arranged, the positioning code track comprises at least one reference point which represents a unique position, wherein the first signal structures forming each reference point are pits, the intervals among the pits of the first signal structures of each reference point are the same, and the number of the pits forming each reference point is sequentially increased or decreased.

The method comprises the following steps: controlling the first optical head assembly to emit a first laser beam and the second optical head assembly to emit a second laser beam while the information storage medium is moved;

determining relative displacement information according to a first electric signal generated by laser reflected by a bump and a pit on a relative displacement measurement code track received by a first optical head assembly, and determining current position information according to a second electric signal generated by laser reflected by a bump and a pit on a positioning code track received by a second optical head assembly;

determining movement direction information of the information storage medium based on the second electrical signal;

determining current actual position information of the information storage medium based on the relative displacement amount information determined by the first electrical signal, and current position information determined by the second electrical signal, and the movement direction information of the information storage medium determined by the second electrical signal.

In one embodiment, the information storage medium further has an absolute displacement measurement track formed thereon, the absolute displacement measurement track including projections and pits arranged according to a gray code, the method further comprising: when the information storage medium is static relative to the first optical head assembly, controlling the first optical head assembly to emit a first laser beam, and reading a third electric signal generated by a signal structure on the absolute displacement measurement code track along the arrangement direction which is perpendicular to the bulges and the pits on the relative displacement measurement code track; determining absolute displacement information from the third electrical signal; and after the information storage medium moves, calculating and determining the current actual position information of the information storage medium according to the relative displacement information determined by the first electric signal and the absolute displacement information determined by the third electric signal.

In one embodiment, the method further comprises: controlling the third optical head assembly to emit a third laser beam when the information storage medium is moved; generating a fourth electrical signal according to the laser reflected by the bumps and pits on the relative displacement measurement code track received by the third optical head assembly; the moving direction of the information storage medium is determined according to a phase difference of the first electrical signal and the fourth electrical signal.

< Displacement measuring System >

Fig. 20 is a schematic structural diagram of a displacement measurement system according to an embodiment of the present invention. The displacement measuring system comprises at least: the signal carrier device 2010 provided in any embodiment of the present invention, the signal sensing device 2020 provided in any embodiment of the present invention, the signal acquisition device 2030, the signal processing device 2040, the signal output device 2050, and the driving device 2060.

The signal sensing means 2020 is used for sensing bumps and pits on the information storage medium track of the signal carrier device 2010 and generating corresponding electrical signals.

The signal collecting device 2030 is used for collecting the electrical signals from the signal sensing device 2020 and transmitting the electrical signals to the signal processing device 2040.

The signal processing device 2040 is used for calculating a displacement amount according to the acquired electrical signal and transmitting the displacement amount to the signal output device 2050. The signal output device 2050 is used for inputting the displacement amount to an external device of the displacement measurement system.

The drive means 2060 is used to ensure that the laser beam is focused on the lands and pits on each track.

In one embodiment of the present invention, the signal sensing means 2020 is used to sense bumps and pits on the information storage medium track of the signal carrier means 2010 and generate a corresponding electrical signal. The signal collecting device 2030 is used for collecting the electrical signals from the signal sensing device 2020 and transmitting the electrical signals to the signal processing device 2040. The signal processing device 2040 is configured to determine a control signal according to the acquired electrical signal, and transmit the control signal to the driving device 2060. The driving device 2060 is configured to perform amplification processing according to the control signal, and transmit the amplified control signal to the torquer in the signal sensing device 2020, so that the torquer in the signal sensing device 2020 drives the focusing objective in the signal sensing device 2020 to perform an auto-focusing function and an absolute displacement measurement scanning function.

< machine Equipment >

One embodiment of the present invention provides a machine tool. The machine device comprises at least: a moving part, a stationary part and a displacement measurement system as provided in the above embodiments.

The signal carrier means is mounted on the moving member. The signal induction device, the signal acquisition device, the signal processing device, the signal output device and the driving device of the displacement measurement system are arranged on the static component.

The machine equipment includes but is not limited to machine tool equipment and robots.

In the case of machine tools, the displacement measurement system can be used to detect the coordinates of the tool and workpiece to observe and track the feed error.

The present invention may be a system, method and/or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions embodied therewith for causing a processor to implement various aspects of the present invention.

The computer readable storage medium may be a tangible device that can hold and store the instructions for use by the instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a Static Random Access Memory (SRAM), a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), a memory stick, a floppy disk, a mechanical coding device, such as punch cards or in-groove projection structures having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media as used herein is not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., optical pulses through a fiber optic cable), or electrical signals transmitted through electrical wires.

The computer-readable program instructions described herein may be downloaded from a computer-readable storage medium to a respective computing/processing device, or to an external computer or external storage device via a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. The network adapter card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in the respective computing/processing device.

The computer program instructions for carrying out operations of the present invention may be assembler instructions, Instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, aspects of the present invention are implemented by personalizing an electronic circuit, such as a programmable logic circuit, a Field Programmable Gate Array (FPGA), or a Programmable Logic Array (PLA), with state information of computer-readable program instructions, which can execute the computer-readable program instructions.

Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.

These computer-readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer-readable medium storing the instructions comprises an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer, other programmable apparatus or other devices implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. It is well known to those skilled in the art that implementation by hardware, by software, and by a combination of software and hardware are equivalent.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein were chosen in order to best explain the principles of the embodiments, the practical application, or technical improvements to the techniques in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the invention is defined by the appended claims.

Claims

1. A signal sensing device for a displacement sensor is characterized by comprising at least two optical head assemblies, namely a first optical head assembly and a second optical head assembly, wherein a relative displacement measurement code track and a positioning code track are both code tracks formed on an information storage medium, the relative displacement measurement code track comprises bulges and pits which are continuously, alternately and uniformly arranged, the positioning code track comprises at least one reference point representing a unique position, wherein first signal structures forming each reference point are pits, intervals among the pits of the first signal structures of each reference point are the same, and the number of the pits forming each reference point is sequentially increased or decreased,

2. The method of claim 1, wherein the absolute displacement measurement track is a track formed on the information storage medium, the absolute displacement measurement track including protrusions and pits arranged in accordance with a Gray code encoding,

3. The method of claim 1, wherein the signal sensing apparatus further comprises a third head assembly,

4. The method of claim 1, wherein the signal sensing device further comprises a third optical head assembly when the information storage medium is used for angular displacement measurement,

5. The signal sensing apparatus of any of claims 1-4, wherein the optical head assembly comprises a laser emitter, an optical path component, and a laser sensor, wherein,

6. The signal sensing apparatus of claim 5 wherein the optical path components of the optical head assembly comprise a beam splitter, a mirror, and a focusing objective lens, wherein,

7. The signal sensing device of claim 5, wherein a piezo-ceramic element is provided in the optical head assembly,

8. The signal sensing apparatus of claim 5, wherein the laser sensor is a four-quadrant distributed photo sensor, and generates a total of four electrical signals, denoted as an electrical signal a, an electrical signal b, an electrical signal c, and an electrical signal d, wherein the sum of the four electrical signals is used to generate an electrical signal corresponding to each code track, and the difference between the electrical signal result obtained by adding the electrical signal a to the electrical signal c and the electrical signal result obtained by adding the electrical signal b to the electrical signal d is used to correct laser focusing.

9. The signal sensing device of claim 5, further comprising two torquers, namely a first torquer and a second torquer, wherein the first torquer is used for driving the focusing objective lens in the optical path component to move along the optical axis direction of the focusing objective lens, so as to ensure that the laser beam is automatically focused on the surface of the protrusion or the pit of each track; the second moment device is used for driving the focusing objective lens so as to control the laser beam to read a third electric signal generated by a signal structure on the absolute displacement measuring code track along a direction perpendicular to the arrangement direction of the bulges and the pits on the relative displacement measuring code track.

10. A method for reading signals on an information storage medium for a displacement sensor, characterized in that the information storage medium is formed with a relative displacement measurement track and a positioning track,

the method comprises the following steps: