JP2003106872A - Device and method for detecting origin in linear sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an origin detection device and origin detection method capable of easily and accurately determining an origin position in a linear sensor in a small-sized and simple constitution. SOLUTION: In the linear sensor 101 provided with a position detection pattern 11 and an origin detection pattern 7, at least the two origin detection patterns 7 and 8 are mutually provided at a position different in a direction intersected with a longitudinal direction of the position detection pattern 11 in parallel, pattern shapes of both the origin detection patterns 7 and 8 are mutually the same, and a pattern 7 of the first origin detection pattern 7 and a pattern of the second origin detection pattern 8 are arranged so that respective phases are met. In the origin detection device 100 in the linear sensor, light transmitting the origin detection patterns 7 and 8 is constituted to be directly input to a sensor means 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an origin detecting device and an origin detecting method in a linear sensor, and more particularly, to a linear sensor capable of easily and accurately determining an origin signal with a simple structure. The present invention relates to an origin detection device and an origin detection method for a sensor.

[0002]

2. Description of the Related Art Lasers and light emitting diodes (L
An optical length measuring device using an ED) and an optical encoder length measuring device using an optical encoder are known.

Since the optical length-measuring device measures the wavelength of a laser or a light emitting diode (LED) as a unit, high accuracy can be obtained.

The optical length measuring device is mainly used for relative position length measuring for measuring the length between two points.

The optical encoder length-measuring device comprises a scale composed of a glass plate, a film, a metal thin plate or the like, an optical grating provided on the scale at a predetermined pitch, and a predetermined distance from the scale. It is composed of a fixed index grating (where the phase of the optical grating and the phase of the fixed index are shifted by 90 degrees) arranged, a fixed light source for irradiating the scale with parallel light, and a light receiving sensor.

When the scale is moved, the optical grating and the fixed index grating are overlapped with each other to generate light and dark.

The light receiving sensor detects this brightness. The optical encoder length measuring device has been put to practical use as a digital displacement meter, and is mainly used as a relative position length measuring device for measuring the length between two points.

Here, the structure of a specific example of a conventional photoelectric transmission type linear encoder, that is, a linear sensor will be described with reference to FIG.

That is, in FIG. 10, a movable scale 3 composed of a transparent member is connected to a spindle 5 provided with a contactor 6, and the movable scale 3 has an optical grating 11 of equal pitch. Are formed.

The light source 1 is provided on one side of the moving scale 3.
And a condenser lens 2, and on the other side, a fixed scale 34 on which optical gratings 47 and 48 of equal pitch are formed and a photodiode 28 which is a light receiving semiconductor element are provided.

The light source 1 and the photodiode 28 face each other with the fixed scale 34 fixed at a fixed position interposed between the movable scale 3 which moves according to the displacement of the object to be measured.

The optical grating 11 provided on the movable scale 3 and the optical gratings 47 and 48 provided on the fixed scale 34 have the same pitch and the same line width, for example, a pitch of 20 μm and a line width of 10 μm. Is manufactured on a very precise scale.

When the spindle 5 moves in the direction of the arrow at the time of measurement and the transparent portion of the optical grating 11 of the moving scale 3 and the transparent portions of the optical gratings 47 and 48 of the fixed scale 34 coincide with each other, the amount of light transmitted through both is It will be the maximum.

On the other hand, when the moving scale 3 moves from this state by 1/2 pitch of the optical grating, the transparent portion and the opaque portion of the optical grating overlap each other, so that the amount of transmitted light becomes minimum.

That is, as the moving scale 3 moves, the output signal from the photodiode 28 becomes a sine wave signal.

If the number of inductions is counted, the moving scale 3
Is calculated.

Generally, the fixed scale 34 is usually provided with two sets of optical gratings 47 and 48, and two sets of photodiodes 28 are provided correspondingly.

The other optical grating 48 is displaced from the one optical grating 47 by ¼ pitch.

FIG. 11 shows when the moving scale 3 moves.
The output signals of the two photodiodes 28 are shown.

When the light transmitted through one optical grating 47 of the fixed scale 34 is represented as the signal A in FIG. 11, the signal B representing the light transmitted through the other optical grating 48 of the fixed scale 34 is the pitch P of the signal A. , The phase is shifted by 1/4 pitch.

It is possible to discriminate between right and left in the moving direction of the moving scale 3 based on the lead / lag of the phase of the signal B with respect to the signal A.

FIG. 12 is a cross-sectional view of a specific example of the above-described conventional linear sensor 40. Two LEDs 1, a moving scale 3, a spindle 5, a fixed scale 34 and two LEDs are used as a light source. A photodiode 28 is provided, and the movable scale 3 is sandwiched between the LED 1 which is a light source, the condenser lens 2, the fixed scale 34, and the photodiode 28.

The two LEDs 1, the condenser lens 2 and the two photodiodes 28 are arranged so as to face each other.

In FIG. 12, 8 is an appropriate frame, and 29 is an appropriate frame.
A is an upper cover portion, 29B is a lower cover portion, 30 is a support base,
18 is a fixed screw, 31 is a support for the main scale 3, 3
2 is an LED support base.

[0025]

However, in the above-mentioned conventional linear sensor, the fixed scale 34 is indispensable because the photodiode 28 detects the overlapping brightness of the moving scale 3 and the fixed scale 34. Since it is impossible to reduce the thickness of the linear sensor,
There is a problem that the size of the linear sensor is large, and further, it is necessary to set the gap between the movable scale 3 and the fixed scale 34 to be as narrow as 10 to 50 μm.
There was also a problem that it was very difficult to make adjustments for aligning the surfaces of the two scales.

On the other hand, in the above-mentioned conventional origin detecting method in the linear sensor, the peak value of the analog signal is sharpened in the method of simply obtaining the peak value of the analog signal output from the photodiode. When the peak value is not sharpened, it is difficult to identify where the peak is due to the influence of noise signals and the like.

In order to solve such a problem, conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 5-296797, the amount of light passing through only a predetermined pitch pattern and the amount of light passing through a random pattern are set. The method for obtaining the difference between the output signals based on the above, and detecting the origin position from the difference value is described in Japanese Patent Laid-Open No. 2000-97726.
In the publication, in a known linear sensor, an origin detection analog signal waveform output from a sensor that receives light transmitted through a predetermined pattern is sliced at a predetermined reference level to generate a digital signal, and the digital signal is generated. It is described for the method of counting the position pulse signal after the signal becomes active and detecting the origin position where the origin is the part of the count value at the time when the digital signal becomes inactive. ing.

However, in any of the above-mentioned conventional examples, the shape of the origin detection analog signal waveform itself is unstable, and therefore, whether it is the difference value or the 1/2 count position, it is absolutely a reliable position. However, it was not fixed at the point of origin detection.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to easily and accurately determine the origin position in a linear sensor while having a small size and a simple structure. The present invention also provides an origin detection device and an origin detection method.

[0030]

In order to achieve the above-mentioned object, the present invention basically adopts the technical constitution as described below.

That is, the first aspect of the present invention is to use a position detecting pattern composed of optical gratings arranged at a predetermined pitch, and an optical grating having a different pattern from the position detecting pattern. A movable main scale provided with an origin detection pattern, a light source means for generating light for irradiating the main scale provided on one side of the main scale, and another side provided for the main scale. A linear sensor composed of a sensor means composed of a light receiving element that receives light transmitted through the main scale optical grating, and the sensor means has transmitted the position detection pattern. The position detection sensor section that directly receives light and the origin detection sensor section that directly receives the light that has passed through the origin detection pattern In addition, the origin detection processing circuit that generates an origin signal in response to the output of the origin detection sensor unit and the position detection signal and the 90-degree phase with each other in response to the output signal from the position detection sensor unit. The origin detection device is a linear sensor configured by a position detection processing circuit that outputs different two-phase square wave signals, and a second aspect of the present invention is a predetermined method. A movable main scale provided with a position detection pattern formed of an optical grating arranged at a predetermined pitch and an origin detection pattern formed of an optical grating having a pattern different from the position detection pattern, the main scale. Light source means for generating light for irradiating the main scale provided on one side of the main scale and the main scale provided on the other side of the main scale. In a linear sensor composed of a sensor means composed of a light receiving element that receives light that has passed through the optical grating, the sensor means directly receives the light that has passed through the origin detection pattern. At the same time, an origin detection analog signal waveform is generated in response to the amount of light transmitted through the origin detection pattern received by the sensor means, and then the phases are different from each other from the origin detection analog signal waveform. This is a method for detecting an origin in a linear sensor configured to form one kind of digital waveform signal and then determine one of the two kinds of digital waveform signals having different phases as an origin signal.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Since the origin detecting device and the origin detecting method according to the present invention adopt the above-mentioned technical structure, the number of light sources is only one, and the fixed scale used conventionally is not necessary. In addition, the arithmetic circuit is simpler than the conventional processing circuit, and the amount of memory can be greatly reduced. Therefore, the size and thickness of the linear sensor itself can be made smaller and thinner, and at the same time the origin position can be detected. An origin detecting device and an origin detecting method capable of easily and accurately making a judgment are provided.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific examples of an origin detecting device and an origin detecting method according to the present invention will be described in detail below with reference to the drawings.

That is, FIG. 1A shows the structure of a specific example of the origin detecting device according to the present invention, and in the drawing, it is composed of optical gratings 20 arranged at a predetermined pitch. Position detection pattern 11 and the position detection pattern 1
The movable main scale 3 provided with the origin detection pattern 7 including the optical grating 21 having a pattern different from 1, and the light for irradiating the main scale 3 provided on one side of the main scale 3 A light source means 1 composed of a generated LED and the like, an optical lens 2 composed of a condenser lens and the like, and an optical grating 20 of the main scale 3 provided on the other side of the main scale 3.
The linear sensor 101 includes a sensor means 23 configured by a light receiving element or the like for receiving light transmitted through the main scale 3, and at least two origin detection patterns 7 and 8 are provided on the main scale 3. Are provided in parallel with each other at different positions in a direction orthogonal to the longitudinal direction of the position detection pattern 11, and the origin detection patterns 7 and 8 have the same pattern shape. The pattern of the first origin detection pattern 7 and the pattern of the second origin detection pattern 8 are arranged such that their phases match each other, and the origin detection pattern 7 , 8 is shown as the origin detection device 100 in a linear sensor configured so that the light transmitted through the sensor 8 is directly input to the sensor means 23.

That is, in the origin detecting apparatus 100 of the present invention, as described above, the fixed scale conventionally used is not used, and the light emitted from the light source is the main scale 3. After passing through the position detecting pattern 11 and the origin detecting patterns 7 and 8, the light is directly incident on the sensor means 23.

The origin detecting patterns 7 and 8 in the present invention are preferably constituted by random patterns.

Further, the linear sensor 10 according to the present invention.
In the first origin detection device 100, the sensor means 23 includes a position detection sensor unit 12 that receives light transmitted through the position detection pattern 11, and the first and second origin detection patterns. It corresponds to 7 and 8 respectively,
A first origin detection sensor unit 9 and a second origin detection sensor unit 9 for receiving light transmitted through the first and second origin detection patterns 7 and 8.
Of the mask portion 2 having the same pattern as the origin detection pattern 21 is provided in the first origin detection sensor portion 9.
4 is provided, and it is desirable that the second origin detection sensor section 10 is provided with a mask section 25 having a pattern in which the origin detection pattern 21 is inverted.

That is, in the present invention, in the above-mentioned structure, in order to accurately determine the origin position, two origin detection patterns 7 and 8 are provided on the main scale 3 and at the same time, The light individually transmitted through the origin detection patterns 7 and 8 is individually detected by the origin detection sensor units 9 and 10 having a mask having a negative and positive relationship, and the respective origin detection sensor units 9 and 10 invert each other. By forming two kinds of current analog signal waveforms having the above relationship and synthesizing the two kinds of current analog signal waveforms and performing IV conversion, it becomes possible to more accurately obtain the analog signal waveform. .

In the present invention, it is also desirable that the analog signal waveform obtained by the IV conversion is further inverted and amplified.

After that, in the present invention, the origin detection analog signal waveform is input to a comparing means having a predetermined reference value, for example, a comparator or the like to perform slice processing to form a digital square waveform signal. Become.

Explaining a more detailed configuration example of the origin detecting device 100 in the linear sensor according to the present invention, the origin detecting device 100 of the linear sensor in FIG. The sensor means 23 has a position detection sensor section 12 for directly receiving the light transmitted through the position detection pattern 11 and an origin detection sensor for directly receiving the light transmitted through the origin detection patterns 7 and 8. Units 9 and 10 are further provided, and an origin detection processing circuit 14 that generates an origin signal in response to the outputs of the origin detection sensor units 9 and 10 and the position detection sensor unit 1 are provided.
In response to the output signal from 2 the position detection signal and 9
It is composed of a position detection processing circuit 13 for outputting a two-phase square wave signal having a 0 ° phase difference and an appropriate counter means 15.

The position detection signal in the position detection processing circuit 13 is the position provided in the sensor means 23 based on the light / dark state of the light transmitted through the position detection pattern 11 provided in the main scale 3. The detection sensor unit 12 converts the analog current value into an analog voltage value by using a known IV conversion means, and then converts the analog voltage value into a digital signal waveform (D2D). , A phase) and at the same time, a digital signal waveform (D2T, B phase) having a phase difference of 90 degrees from the digital signal waveform (D2D) is formed.

Further, in the origin detection device 100 in the linear sensor according to the present invention, the origin detection processing circuit 14 responds to the outputs of the origin detection sensor sections 9 and 10 with the origin detection analog signal. Origin detection analog signal waveform output means 16 that outputs a waveform, and a digital waveform signal that forms two types of digital waveform signals having different phases from the origin detection analog signal waveform output by the origin detection analog signal waveform output means 16 Forming means 17, 2
Origin signal determining means 18 for deciding, as an origin signal, one of the positions having different phases among the seed digital waveform signals.
It is preferable that it is composed of and.

Further, the digital waveform signal forming means 17 in the present invention determines the first digital waveform signal and the activation state period of the first digital waveform signal from one input origin detection analog signal waveform. It is desirable to have a function of generating a second digital waveform signal such that an activated state period is included therein.

On the other hand, the origin signal determining means 18 in the present invention is formed by the two digital waveform signals formed by the digital waveform signal forming means 17.
It is desirable to have a function of determining only one of the predetermined signal parts having different phases out of the two signal parts having different phases as the origin signal.

Further, the origin signal determining means 18 in the present invention outputs 2 from the position detection processing circuit 13.
A phase square waveform signal (generally referred to as A phase / B phase, which is different from each other by 90 degrees in phase) is used to move the main scale in either forward or backward direction. , It is necessary to be configured so that predetermined parts having different phases are selected.

That is, in the present invention, as described above,
In the digital waveform signal forming means 17, since at least two portions having different phases are formed,
Whether the main scale 3 moves to the right or to the left, it is configured such that a portion having a different phase in a predetermined direction is selected, and the two-phase square waveform is used. It will be executed by using the movement direction discrimination function of the main scale using signals.

On the other hand, the origin detection analog signal waveform output means 16 used in the present invention includes the first and second origin detection analog signal waveform output means 16.
It may have a function of synthesizing analog current waveforms output from the origin detection sensor units 9 and 10 and performing IV conversion to output an analog voltage waveform signal.

FIG. 1B is a sectional view of the origin detecting device 100 according to the present invention described above, and its basic construction is substantially the same as that of the conventional linear sensor shown in FIG.
The same components are designated by the same reference numerals.

The feature of the present invention is that there is no fixed scale facing the main scale 3 and the light source 1 is a single LE.
The sensor means 23, which is constituted by D and directly faces the main scale 3, has a configuration in which the first and second origin detection sensor portions 9 and 10 and the position detection sensor portion 12 are vertically arranged. is doing.

A concrete circuit configuration and an example of the origin detection analog signal waveform output means 16 used in the present invention are shown in FIGS.

Further, the circuit configuration of the first concrete example of the digital waveform signal forming means 17 in the present invention is as shown in FIG. 2, and as will be described later, the origin detection analog signal waveform forming. The analog voltage waveform signal Azu input from the means 16 is inverted and amplified through an appropriate inverting amplifier circuit 171 to form an inverted and amplified analog voltage waveform signal Zu, which is then divided into two and the one analog voltage waveform signal Z is obtained.
u1 is input to the first comparison circuit 172 having the first reference signal Vref 1 and the first comparison circuit 172 slices the first digital signal at the level of the first reference signal Vref 1. In addition to forming the waveform signal CZU, the other analog voltage waveform signal Zu2 is used as the first reference signal Vre.
The second digital waveform signal CZ is input to the second comparison circuit 173 having the second reference signal Vref 2 different from f 1.
By forming D, the activation period is different, and the function has such a function that the activation period of one digital waveform signal is included in the activation period of the other digital waveform signal.

An example of the output waveform in each circuit in the waveform processing method using the first concrete example of the digital waveform signal forming means 17 in the present invention is shown in FIG. ing.

Further, as another function of the digital waveform signal forming means 17 in the present invention, as shown in the circuit configuration shown in FIG. 4 and the waveform diagram of FIG. 5, the origin detection analog signal waveform signal formation is performed. First inversion amplification offset means 1 having the analog voltage waveform signal AZU input from the means 16 as a predetermined reference signal value Voff1 as an offset value
73 to form a first digital waveform signal ZU, and a reference signal value different from the above-mentioned predetermined reference signal value Voff1 in the analog voltage waveform signal AZU input from the origin detection analog signal waveform forming means 16. Vof
It is input to the second inverting amplification offset means 174 having f2 as an offset value to input the second digital waveform signal ZD.
To form offset analog voltage waveform signals ZC and ZD whose phases are different from each other, and then, both offset analog voltage waveform signals ZC and ZD have the same reference signal value Vref and the first and second offset analog voltage waveform signals ZC and ZD. Of the first digital waveform signal CZU and the second digital waveform signal CZD by individually inputting them to the comparator circuits 172 and 173 of FIG. Has a function of being configured to be included in the activation period of the other digital waveform signal.

As described above, the origin signal ZE in FIG.
RO operates so as to select only the specified origin signal indicated by X for both forward and backward of the two origin signals D1T generated during one stroke.

In the present invention, it is desirable that the minimum unit position signal detected by the position detection sensor section 12 and the origin signal output from the origin signal determining means 18 are synchronized. .

Further, it is desirable that the optical grating forming the origin detecting pattern used in the present invention is composed of a pattern having a random optical grating interval. The lattice spacing is configured to change randomly.

Next, a specific example of the configuration of the origin signal determining means 18 used in the present invention will be described in detail with reference to FIGS. 6 to 9.

First, the first concrete example of the configuration of the origin signal determining means 18 in the present invention is as shown in the circuit block diagram of FIG. 6 and the waveform diagram of FIG. One of the two types of digital waveforms CZU and CZD formed by any specific example of the signal forming circuit 16 is directly input to one input terminal of the AND gate circuit A1, and the other is inverted by the inverter INV to form an AND gate circuit. By inputting to the other input terminal of A1, as shown by the waveform a1, one stroke of the main scale,
That is, in the process of moving to the right or to the left, the two different portions of the digital waveforms CZU and CZD (origin signals) having different phases are output as "H" level.

On the other hand, the D-type flip-flop (DF / F /
F) D1 is a function of selecting only one of the two origin signals (“H” level portion of the output waveform a1 of the AND gate circuit A1) generated in one stroke. Having a first terminal at the control terminal T
When the second origin signal a1 is input, the output signal D1Q of the output terminal Q becomes "H" level and the output terminal Q
The output signal D1Q 'of the bar becomes "L" level, and when the second relevant origin signal a1 is input next, the output terminal Q
The output signal D1Q of the output terminal D1Q 'is set to the "L" level, and the output signal D1Q' of the output terminal Q is set to the "H" level.

On the other hand, the inversion signal D1C of the digital waveform signal CZU is input to the clear terminal C. Normally, the clear terminal C is in the clear state, but while the inversion signal D1C is being input. Only the D-F / F (D
1) is configured to be activated.

Further, since the DF / F (D1) has a so-called "plow" structure, the DF / F (D1) is
It operates so that the cycle of the signal (DIT) which is a timing signal input to the control terminal T of is reduced to 1/2.

That is, the output signal from the output terminal Q of the D-F / F (D1) is the first origin signal a1 (D1T).
Is input, "H" level, second origin signal a1
When (D1T) is input, "L" level is input, when the third origin signal a1 (D1T) is input, "H" level is input, and when the fourth origin signal a1 (D1T) is input, "L" level is input. ”
It operates so as to reach the level.

That is, in the D-F / F (D1), since the timing signal (D1T) is the output waveform a1 of the AND gate circuit A1, only two shots are output during one stroke, so that the D- Regarding the operation of the F / F (D1), normally, the output signal D1Q of the output terminal Q is at the “L” level, but the inversion signal of the digital waveform signal CZU is input and the clear state is canceled during that period. When the first origin signal a1 or the signal D1T is input to the control terminal T, the output signal D1Q of the output terminal Q becomes “H” level, and the second origin signal a1 or the signal D1T is input to the control terminal T. Then, the output signal D1Q of the output terminal Q is "L".
When the inverted signal of the digital waveform signal CZU disappears, the state returns to the clear state, and thereafter, the output signal D1Q of the output terminal Q maintains the "L" level.

Also, a D-type flip-flop (DF / F)
D2 is a circuit having a function for discriminating the traveling direction of the main scale 3, and the position detection processing means 1 is provided.
The A-phase digital waveform signal (D2D) and the B-phase digital waveform signal (D2T) of the digital waveform signal output from 3 are individually input to the control terminal T and the data terminal D, and, for example, the A-phase signal ( "Forward" when the B-phase signal (D2T) rises when D2D) is at "H" level
, The D-F / F (D2) is output terminal Q
Output signal D2Q becomes "H" level in "going forward",
"Return" operates so that it becomes "L" level.

On the other hand, AND gate A2 and AND gate A
3 will be described. The AND gate A2 is for "outgoing", and becomes "H" level when "outgoing".
AND between the output of F / F (D2) and the output of D-F / F (D1) indicating "H" level until CZD becomes "H" level again after CZU becomes "H" level. AN to take
It is a D gate, and the AND gate A3 is for "return",
The output of DF / F (D2) which becomes "H" level at the time of "return" and D which is "H" level from when CZD becomes "L" level until CZU becomes "H" level. -F /
It is an AND gate that takes an AND with the output of F (D1).

Further, the AND gate A4 is connected to the above-mentioned AND gate.
AND of the output a2 of the gate A2 and the output a3 of the AND gate A3, which is the output of the OR gate circuit OR, and the output signal a1 of the AND gate A1 which is the two origin signals generated in one stroke It is a gate and has a function of restricting to select the origin signal a1 which is generated while the signal OR1 output from the OR gate is at "H" level.

That is, in the above-described specific example, the origin signal is always the same portion of the two origin signals generated during one stroke of the main scale 3 regardless of the traveling direction of the main scale. Only the generated origin signal needs to be selected with certainty. Therefore, the D-F /
The output of F (D1) becomes "H" level when the first origin signal a1 is input in the forward direction of the main scale 3, and "F" when it receives the second origin signal a1. Since it becomes the L "level, the output of the" H "level of the D-F / F (D1) is" D-F /
Select with F (D2) and select "D-F / F" for "Return".
(D1) output of "L" level (actually, the DF
/ F (D1) Q-bar output (D1Q ') is used, so "H" level is used).
It will be selected in (D2).

Next, a second specific example of the configuration of the origin signal determining means 18 according to the present invention is as follows, as shown in the circuit block diagram of FIG. 8 and the waveform diagram of FIG.
The D-type flip-flop (DF / F) D3 to which the A-phase and B-phase signals are input has the same function as the DF / F (D2) in the first specific example described above. Therefore, detailed description thereof will be omitted here.

Next, a D-type flip-flop (DF / F /
F) D4 is provided to prevent chattering of the original origin detection signal CZD and to synchronize with the B phase.

That is, the CZD signal is input to the clear terminal C of the D-F / F (D4), and normally the D-F / F is used.
Although (D4) is in a non-clear state, it is in a clear state only while the CZD signal is being input.

Therefore, normally, the B phase is always the DF / F concerned.
Since it is input to the control terminal T of F (D4), the D
The output signal D4Q from the output terminal Q of -F / F (D4) is
It is at "H" level, and when CZD is input, the output signal D4Q immediately becomes "L" level, and then C
When ZU goes to "L" level and then B phase rises,
The output signal D4Q becomes "H" level.

Further, a D-type flip-flop (DF / F)
D5 is provided to prevent chattering of the original origin detection signal CZU and to synchronize with the B phase.

That is, the CZU signal is input to the clear terminal C of the D-F / F (D5), and normally the D-F / F
Although (D5) is in a non-clear state, it is in a clear state only while the CZU signal is being input.

Therefore, normally, the B phase is always the DF / F concerned.
Since it is input to the control terminal T of F (D5), the D
The output signal D5Q from the output terminal Q of -F / F (D5) is
It is at "H" level, and when CZU is input, the output signal D5Q immediately becomes "L" level, and then C
When ZU goes to "L" level and then B phase rises,
The output signal D5Q becomes "H" level.

On the other hand, a D-type flip-flop (DF / F /
F) D6 is the origin signal (actually, a D-type flip-flop (D
-F / F) D7Q which is the output signal of the output terminal Q of D7 or D2Q which is the output signal of the output terminal Q of the D-type flip-flop (D-F / F) D8.
It is a circuit for selecting one of the two signals), and becomes "H" level when the first origin signal is input and becomes "L" level when the second origin signal is input.

That is, the D5QB which is the output of the output terminal Q bar of the D-F / F (D5) is input to the clear terminal C of the D-F / F (D6), and normally, the D5QB is output. DF / F (D6) is in the clear state, but CZ
While the U signal is being input, and while the CZU signal is at the "L" level and the next B phase has risen, the CZU signal is activated.

On the other hand, the D-F / F (D6) also has a so-called plow structure.

Further, the control terminal T of the D-F / F (D6) is supplied with the D-F / F (D4) as a timing signal.
Since the output signal D4QB of the Q-bar terminal of the above is input and only one output signal D4QB is generated,
Regarding the operation of -F / F (D6), the output signal D6Q from the Q terminal is normally at "L" level, but when the CZU signal becomes "H" level, the clear state becomes the non-clear state, and D -Output signal D4 from the Q bar terminal of F / F (D4)
When QB is input to the control terminal T, it goes to "H" level, the CZU signal goes to "L" level, and when the next phase B rises, a clear signal is input, so it goes to "L" level.

The AND gate A9 is a timing signal for synchronizing the origin signal with the A phase and the B phase. When both the A phase and the B phase are at the "H" level, the signal a9 at the "H" level is provided. Is output.

Further, the AND gate A5 receives the CZU signal and C
When the phase of the ZD signal is different, to be more precise, it becomes "H" level only when the phases of the output signals of the D-F / F (D4) and the D-F / F (D5) are different, and Indicates that there is an origin.

This signal becomes "H" level at two points.

At this time, the CZU signal and the CZD signal are AN
It is desirable that the output of the D gate A9 be in a positional relationship such that it includes exactly two outputs.

Further, the AND gate A6 is a gate circuit for ANDing the output of the AND gate A9 and the output of the AND gate A5, and the origin signal is synchronized with the A phase and the B phase at two locations where the origin exists. Two timing signals for taking each are included.

On the other hand, a D-type flip-flop (DF / F /
F) D7 is a circuit for synchronizing the "return" origin signal with the A phase and B phase, and when the signal a6 which is the first "A phase, B phase synchronization timing signal" is input. It becomes "H" level and becomes "L" level when the second signal "A6, B-phase synchronization timing signal" a6 is input.

That is, the output signal a5 of the AND gate A5 is input to the clear signal terminal of the D-F / F (D7), and normally, while the clear signal is being input, the D-
The output of the F / F (D7) is in an activated state at two locations where the origin is present, that is, the output is at "H" level.

The D-F / F (D7) also has a so-called plow structure.

On the other hand, the AND gate A is supplied to the control terminal T of the D-F / F (D7) as the timing signal DT7.
Since the output signal a6 of 6 is input and the output signal a6 of the AND gate A6 generates only two pulses in one operation, the operation of the D-F / F (D7) is usually Indicates that the output signal D7Q of the output terminal of the D-F / F (D7) is at "L" level, but the pulse a6
When is entered, the clear state is released and the first "A
"H" level when the signal a6 that is the "phase and B phase synchronization timing signal" is input, and the "L" level when the signal a6 that is the second "A phase and B phase synchronization timing signal" is input. Then, when the signal a6, which is the second "A-phase and B-phase synchronization timing signal", is input, it becomes "L" level.

After that, when the pulse signal a6 becomes "L" level, the state returns to the clear state, so that the output is "L".
It remains at the level.

Then, the pulse signal a6 is again "H".
When it reaches the level, the clear state is released and the first "A
"H" level when the signal a6 that is the "phase and B phase synchronization timing signal" is input, and the "L" level when the signal a6 that is the second "A phase and B phase synchronization timing signal" is input. Then, when the signal a6, which is the second "A-phase and B-phase synchronization timing signal", is input, it becomes "L" level.

After that, when the pulse signal a6 becomes "L" level, the state returns to the clear state, so that the output is "L".
It remains at the level.

The signal width of the D-F / F (D7) is a signal that is the next "A phase, B phase synchronization timing signal" from the rise of the signal "a6" that is the "A phase, B phase synchronization timing signal". Up to the rise of a6.

On the other hand, the D-type flip-flop (DF-F /
F) D8 is a circuit for synchronizing the "outgoing" origin signal with the A phase and B phase, and the signal a6B which is the first "inverted signal of the A phase and B phase synchronization timing signal" is input. Signal "a6", which is the "H" level when it is turned on, and which is the second "inverted signal of the A-phase and B-phase synchronization timing signals"
When B is input, it goes to "L" level.

That is, the output signal a5 of the AND gate A5 is input to the clear signal terminal of the D-F / F (D8), and normally, while the clear signal is input, the D-
The output of the F / F (D8) is in an activated state at two points where the origin is present, that is, the output is at "H" level.

The D-F / F (D8) also has a so-called plow structure.

On the other hand, the AND gate A is supplied to the control terminal T of the D-F / F (D8) as the timing signal DT8.
Since the inversion signal a6B of the output signal a6 of 6 is input and the inversion signal a6B of the output signal a6 of the AND gate A6 is generated only two pulses in one operation, the D-F / F ( As the operation of D8),
Normally, the output signal D8Q of the output terminal of the D-F / F (D8) is at "L" level, but when the pulse a6B is input, the clear state is released, and the first "A phase" , B
Signal a which is "inverted signal of phase synchronization timing signal"
When 6B is input, it becomes “H” level, and when the signal a6B which is the second “inverted signal of A-phase and B-phase synchronization timing signal” is input, it becomes “L” level,
When the signal a6B, which is the second "inverted signal of the A-phase and B-phase synchronization timing signals", is input, it becomes the "L" level.

After that, when the pulse signal a6B becomes "L" level, the state returns to the clear state.
It remains at "L" level.

When the pulse signal a6B becomes "H" level again, the clear state is released and when the signal a6B which is the first "A-phase and B-phase synchronization timing signal invert signal" is input. Becomes "H" level,
When the signal a6B, which is the "inverted signal of the A-phase and B-phase synchronization timing signals", is input at the "L" level, the second "inverted signal of the A-phase and B-phase synchronization timing signals" is generated. When a certain signal a6B is input, it becomes "L" level.

After that, when the pulse signal a6B becomes "L" level, the state returns to the clear state, so that the output is
It remains at "L" level.

The signal width of the D-F / F (D8) is the same as the "A phase, B phase synchronization" from the rise of the signal a6B which is the "inversion signal of the inversion signal of the A phase, B phase synchronization timing signal". Up to the rise of the signal a6B, which is the "inverted signal of the timing signal".

Next, the AND gate A7 is for return,
DF / F (D3) which becomes "H" level at the time of "return"
Gate of AND output of the output signal of D-F / F (D6) which is "H" level until the CZD signal is input, and the origin signal synchronized with A phase and B phase Further, the AND gate A8 is used for the going, and the output of the D-F / F (D3) which becomes the "H" level at the time of "going" and the C
DF / that becomes "H" level after the ZD signal is input
It is a gate that ANDs the three signals of the output of F (D6) and the origin signal synchronized with the A phase and the B phase.

As described above, the origin signal ZE in FIG.
RO is one of the two origin signals a5 generated during one stroke,
It operates so as to select only the specified origin signal indicated as Y in both the forward and backward directions.

In the present invention, as described above, the forward and backward origin signals are signals synchronized with the A phase and B phase so as to surround the B phase recess.

As is clear from the above description, as the origin detection method in the linear sensor according to the present invention, for example, a position detection pattern formed of optical gratings arranged at a predetermined pitch and A movable main scale provided with an origin detection pattern made of an optical grating having a pattern different from the position detection pattern,
A light source means provided on one side of the main scale for generating light for irradiating the main scale and a light receiving element provided on the other side of the main scale for receiving light transmitted through an optical grating of the main scale. In the linear sensor composed of the sensor means composed of, the sensor means directly receives the light transmitted through the origin detecting pattern, and the origin detecting pattern received by the sensor means. The origin detection analog signal waveform is generated in response to the light amount of the light that has passed through, and then two types of digital waveform signals having different phases are formed from the origin detection analog signal waveform, and then the two types The linear sensor that is configured to determine one position in the digital waveform signal of It is in origin detection method.

In the origin detecting method for the linear sensor according to the present invention described above, an offset origin obtained by applying an offset different from the origin detecting analog signal waveform and the origin detecting analog signal waveform. After forming two types of digital waveform signals with a comparator having the same reference voltage as the detected analog signal waveform, one of the two types of digital waveform signals having different phases is always determined as the origin signal. It is desirable that the analog detection signal waveform of the origin is formed into two kinds of digital waveform signals by two comparators having different reference voltages, and then the phases of the two kinds of digital waveform signals are different. It is desirable that one of the parts is always determined as the origin signal.

Further, in the present invention, at least two origin detecting patterns are provided on the main scale in parallel to each other at different positions in the direction orthogonal to the longitudinal direction of the position detecting pattern. However, the pattern shapes of the two origin detection patterns are the same, and the phases of the first origin detection pattern and the second origin detection pattern are the same. It is also preferable that the arrangement is such that the light transmitted through the origin detection pattern is directly input to the sensor means.

Further, in the present invention, it is also preferable that the origin detection pattern is a random pattern.

On the other hand, in the origin detecting method according to the present invention, the sensor means directly receives the light transmitted through the position detecting pattern, and the first and second detecting means. And a first origin detection sensor section and a second origin detection sensor section that correspond to each of the origin detection patterns and directly receive the light transmitted through the first and second origin detection patterns. A mask part having the same pattern as the origin detection pattern is provided on the first origin detection sensor part, and
It is also preferable to provide a mask section having a pattern in which the origin detection pattern is inverted to the origin detection sensor section, and further, to output the minimum unit position signal detected by the position detection sensor section. It is also desirable that the origin signal is configured to be synchronized.

[0109]

According to the present invention, it is possible to solve the problems of the prior art described above, and to easily and accurately determine the origin position in the linear sensor while having a small size and a simple structure. The origin detecting device and the origin detecting method are realized.

Further, according to the present invention, it is possible to surely determine the origin position by moving operation in one direction without reciprocating the main scale, and by making the frequency of the optical grating to be used finer. , It becomes possible to obtain a more accurate origin position.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a specific example of an origin detection device in a linear sensor of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a specific example of an origin detection analog signal waveform forming circuit and a digital waveform signal forming circuit of the origin detecting device according to the present invention.

FIG. 3 is a waveform diagram obtained in the specific example shown in FIG.

FIG. 4 is a circuit diagram showing the configuration of another specific example of the origin detection analog signal waveform forming circuit and the digital waveform signal forming circuit of the origin detecting device according to the present invention.

FIG. 5 is a waveform chart obtained in the specific example shown in FIG.

FIG. 6 is a circuit diagram for explaining the configuration of a specific example of the origin signal detecting means in the present invention.

FIG. 7 is a waveform diagram obtained in the specific example shown in FIG.

FIG. 8 is a circuit diagram illustrating the configuration of another specific example of the origin signal detecting means in the present invention.

9 is a waveform diagram obtained in the specific example shown in FIG.

FIG. 10 is a diagram illustrating a configuration of a specific example of a conventional linear sensor.

FIG. 11 is a diagram illustrating an example of A-phase and B-phase signals in a specific example of a conventional linear sensor.

FIG. 12 is a cross-sectional view illustrating the configuration of a specific example of a conventional linear sensor.

[Explanation of symbols]

1 light source means 2 optical lens 3 main scale 7 Origin detection pattern 8 Origin detection pattern 9 First origin detection sensor section 10 Second origin detection sensor section 11 Position detection pattern 12 Position detection sensor section 13 Position detection processing circuit 14 Origin detection processing circuit 15 Counter means 20, 21 Optical grating 23 Sensor means 24, 25 mask part 100 origin detector 101 linear sensor

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F103 BA31 BA32 CA02 DA01 DA12                       EA02 EA15 EB06 EB13 EB33                       EC04 ED07 ED17 ED19 FA12

Claims (19)

[Claims] 1. A movement provided with a position detecting pattern made of optical gratings arranged at a predetermined pitch and an origin detecting pattern made of an optical grating having a pattern different from the position detecting pattern. Possible main scale, light source means provided on one side of the main scale to generate light for irradiating the main scale, and light provided on the other side of the main scale and transmitted through the optical grating of the main scale. A linear sensor composed of a sensor means composed of a light-receiving element for receiving light, and at least 2
The origin detection patterns are provided in parallel at different positions in the direction orthogonal to the longitudinal direction of the position detection pattern, and the origin detection patterns of both the patterns have the same shape. Yes and the first
The pattern of the origin detection pattern and the pattern of the second origin detection pattern are arranged such that their phases match each other, and the light transmitted through the origin detection pattern directly An origin detection device in a linear sensor, characterized in that it is configured to be input to the sensor means. 2. The origin detecting device in a linear sensor according to claim 1, wherein the origin detecting pattern is composed of a random pattern. 3. The sensor means corresponds to each of the first and second origin detecting patterns, and a position detecting sensor section that receives light transmitted through the position detecting pattern. And a first origin detection sensor section for receiving light transmitted through the second origin detection pattern and a second origin detection sensor section, and in the first origin detection sensor section. Is provided with a mask part having the same pattern as the origin detection pattern, and the second origin detection sensor part is provided with a mask part having a pattern in which the origin detection pattern is inverted. The origin detection device in the linear sensor according to claim 1, wherein the origin detection device is provided. 4. A movement provided with a position detecting pattern made of optical gratings arranged at a predetermined pitch and an origin detecting pattern made of an optical grating having a pattern different from the position detecting pattern. Possible main scale, light source means provided on one side of the main scale to generate light for irradiating the main scale, and light provided on the other side of the main scale and transmitted through the optical grating of the main scale. Which is a linear sensor composed of a sensor means composed of a light receiving element for receiving, and the sensor means having a position detection sensor section for directly receiving the light transmitted through the position detection pattern, An origin detection sensor unit that directly receives the light that has passed through the origin detection pattern is provided,
Furthermore, an origin detection processing circuit that generates an origin signal in response to the output of the origin detection sensor section, and a two-phase method in which the position detection signal and the 90 degree phase differ from each other in response to the output signal from the position detection sensor section An origin detecting device in a linear sensor, comprising: a position detection processing circuit that outputs a square wave signal. 5. The origin detection processing circuit outputs the origin detection analog signal waveform output means for outputting the origin detection analog signal waveform in response to the output of the origin detection sensor section, and the origin detection analog signal waveform output means. Digital waveform signal forming means for forming two kinds of digital waveform signals having different phases from the origin detection analog signal waveform, and one of the two kinds of digital waveform signals having different phases is the origin signal. 5. The origin detecting device in the linear sensor according to claim 4, further comprising: origin signal determining means for determining as. 6. The digital waveform signal forming means is configured so that, from the input one origin detection analog signal waveform, a first digital waveform signal and an activation state period of the first digital waveform signal are in an activation state period. 6. The origin detecting device in the linear sensor according to claim 5, which has a function of generating a second digital waveform signal such that 7. The origin signal determining means has a predetermined one of two signal portions having different phases formed in the two digital waveform signals formed by the digital waveform signal forming means. 7. The origin detecting device for a linear sensor according to claim 6, which has a function of determining only different parts as origin signals. 8. The origin signal determining means uses a two-phase square waveform signal output from the position detection processing circuit,
8. The main scale is configured such that a predetermined site having a different phase is selected regardless of whether the main scale moves in the forward path or the return path.
Origin detection device in the described linear sensor. 9. The origin detection analog signal waveform output means has a function of synthesizing and converting the analog current waveforms output from the first and second origin detection sensor sections and outputting an analog voltage waveform signal. The origin detection device in the linear sensor according to claim 5, wherein the origin detection device is provided. 10. The digital waveform signal forming means divides the analog voltage waveform signal input from the origin detecting analog signal waveform forming means into two parts, and inputs one of them into a comparison circuit having a first reference signal. To generate a first digital waveform signal and input the other to a comparator circuit having a second reference signal different from the first reference signal to form a second digital waveform signal, thereby activating the second digital waveform signal. 7. The period is different, and the function has such a function that the activation period of one digital waveform signal is included in the activation period of the other digital waveform signal.
Origin detection device in the linear sensor described in 1. 11. The digital waveform signal forming means forms the first digital waveform signal by inputting the analog voltage waveform signal input from the origin detection analog signal waveform forming means to a comparison circuit having a predetermined reference signal. Along with
An offset analog voltage waveform signal obtained by applying a predetermined offset to the analog voltage waveform signal input from the origin detection analog signal waveform forming means to have a different phase is input to a comparison circuit having the same reference signal as the predetermined reference signal. Then, by forming the second digital waveform signal, the activation period is different, and the activation period of one digital waveform signal is included in the activation period of the other digital waveform signal. The origin detecting device in the linear sensor according to claim 5 or 6, wherein the origin detecting device is provided. 12. The linear sensor according to claim 1, wherein the minimum unit position signal detected by the position detection sensor unit and the output origin signal are synchronized. Origin detection device in. 13. A movement provided with a position detection pattern formed of optical gratings arranged at a predetermined pitch and an origin detection pattern formed of an optical grating having a pattern different from the position detection pattern. Possible main scale, light source means provided on one side of the main scale to generate light for irradiating the main scale, and light provided on the other side of the main scale and transmitted through the optical grating of the main scale. In a linear sensor composed of a sensor means composed of a light receiving element for receiving the light, the sensor means directly receives the light transmitted through the origin detection pattern, and the sensor means receives the light. Generates the origin detection analog signal waveform in response to the amount of light transmitted through the origin detection pattern. Then, after forming two types of digital waveform signals having different phases from the origin detection analog signal waveform, one position of the two types of digital waveform signals having different phases is used as the origin signal. Origin detection method in linear sensor characterized by being configured to determine. 14. The origin detection analog signal waveform and the offset origin detection analog signal waveform obtained by applying a different offset to the origin detection analog signal waveform are used to generate two types of digital waveform signals by a comparator having the same reference voltage. 14. The origin detecting method for a linear sensor according to claim 13, wherein, after being formed, one of the two types of digital waveform signals having different phases is always determined as the origin signal. . 15. After the origin detection analog signal waveform is formed into two kinds of digital waveform signals by two comparators having different reference voltages, one of the two kinds of digital waveform signals having different phases is always operated. The device according to claim 1, wherein the origin signal is determined.
The origin detection method in the linear sensor described in 3. 16. The main scale has at least 2
The origin detection patterns are provided parallel to each other at different positions in a direction orthogonal to the longitudinal direction of the position detection pattern, and the origin detection patterns of both the patterns may have the same shape. The pattern of the first origin detection pattern and the pattern of the second origin detection pattern are arranged such that their phases match each other, and the light transmitted through the origin detection pattern is directly input to the sensor means. The origin detection method for a linear sensor according to any one of claims 13 to 15, wherein: 17. The origin detecting method for a linear sensor according to claim 13, wherein the origin detecting pattern is a random pattern. 18. The position detecting sensor section for directly receiving the light transmitted through the position detecting pattern to the sensor means, and the first and second origin detecting patterns respectively corresponding to the first and second origin detecting patterns. And a first origin detection sensor section and a second origin detection sensor section for directly receiving the light transmitted through the second origin detection pattern, and
The first origin detection sensor section is provided with a mask section having the same pattern as the origin detection pattern, and the second origin detection sensor section has a pattern in which the origin detection pattern is inverted. 18. The origin detection method for a linear sensor according to claim 13, wherein a mask portion is provided. 19. The minimum position signal detected by the position detection sensor unit and the output origin signal are synchronized with each other.
The origin detection method in the linear sensor according to any one of 3 to 18.