CN218765338U - Fixed grating and photoelectric encoder - Google Patents
Fixed grating and photoelectric encoder Download PDFInfo
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- CN218765338U CN218765338U CN202222802263.7U CN202222802263U CN218765338U CN 218765338 U CN218765338 U CN 218765338U CN 202222802263 U CN202222802263 U CN 202222802263U CN 218765338 U CN218765338 U CN 218765338U
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- 239000011248 coating agent Substances 0.000 claims description 5
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- 238000010586 diagram Methods 0.000 description 9
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- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 1
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- 229910000449 hafnium oxide Inorganic materials 0.000 description 1
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
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Abstract
The utility model provides a decide grating, decide grating and be used for photoelectric encoder, its characterized in that: the fixed grating comprises: a plurality of absolute code channels and at least one sinusoidal code channel positioned at two sides of an optical center are sequentially arranged on an optical glass carrier; wherein the relation between the number N of the absolute code channels and the number of the scribed lines of the sinusoidal code channels is N =2 n . The scheme of the utility model can solve the problem of low subdivision precision caused by non-sinusoidal signals; and the problem that two requirements of high resolution and small size of an absolute photoelectric encoder are difficult to meet simultaneously can be solved.
Description
Technical Field
The utility model relates to a photoelectric technology field, more specifically relate to a decide grating and photoelectric encoder.
Background
The photoelectric encoder is an angle measuring device integrating optics, mechanics and electricity, converts optical signals into electric signals through a mechanical structure and a signal processing circuit, and accordingly achieves direct or indirect measurement of various physical quantities such as angular displacement, speed and position.
In an absolute photoelectric encoder, the encoding of each angle in a circle can be unique through the absolute encoding of a moving grating. In order to satisfy both the requirements of high resolution and small size, the signals must be processed by electronic subdivision. The source signal required for electronic subdivision is the fundamental stone of electronic subdivision. The generation of the source signal depends on the pattern design of the fixed grating. At present, most of fixed grating designs realize signal output as quasi-sine by changing the shape of a window, and cannot meet the high-precision requirement of subdivision; the patent in publication No. CN106248117B proposes a stepped fixed grating, which can improve the sinusoid of a source signal to a certain extent, but still has a large harmonic content.
Therefore, a fixed grating capable of generating a sinusoidal signal is required to improve the accuracy of subdivision.
The above information disclosed in this background section is only for further understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.
SUMMERY OF THE UTILITY MODEL
The utility model relates to a decide grating and photoelectric encoder. The scheme of the utility model can solve the problem of low subdivision precision caused by non-sinusoidal signals; and the problem that two requirements of high resolution and small size of an absolute photoelectric encoder are difficult to meet simultaneously can be solved.
The first aspect of the utility model provides a decide grating, decideThe grating is used for the photoelectric encoder, and is characterized in that: the fixed grating comprises: the optical system comprises a plurality of absolute code channels and at least one sinusoidal code channel, wherein the absolute code channels and the sinusoidal code channels are sequentially arranged; wherein the relation between the number N of the absolute code channels and the number of the scribed lines of the sinusoidal code channels is N =2 n . The number of the scribed lines refers to the number of the scribed lines of the movable grating corresponding to the scribed lines; where the number of ticks represents the number of cycles of the signal.
According to the utility model discloses an embodiment, wherein, sinusoidal code channel is a plurality of, a plurality of sinusoidal code channels stagger 90 degrees in proper order on the phase place.
According to the utility model discloses an embodiment, wherein, absolute code track is used for producing the absolute code of the single circle that corresponds unique positional information, and wherein, sinusoidal code track still is used for producing sinusoidal signal correspond the sinusoidal signal of a period in the absolute code of every single circle, and the sinusoidal signal of one of them period is a period of sinusoidal signal.
According to an embodiment of the present invention, wherein the light transmittance of the sinusoidal code channel is changed by a gradient coating film.
According to the utility model discloses an embodiment, wherein, work as when photoelectric encoder's movable grating moves, through the photocurrent of sinusoidal code track output is: i (Δ x) = P × I × S (Δ x),
wherein, P is the light intensity of the light source, S is the light transmission area of the sine code channel, and Delta x is the movement variable of the movable grating relative to the fixed grating; light transmittance of sine code channel I
According to the utility model discloses an embodiment, wherein, the material of deciding the grating is optical glass, optical glass does the carrier of sinusoidal code channel and absolute code channel groove.
According to an embodiment of the present invention, the scribe line is a window formed on the optical glass.
According to the utility model discloses an embodiment, wherein, carry out interpolation operation through the sinusoidal function to a plurality of sinusoidal code track light transmission area changes and improve photoelectric encoder's resolution ratio.
According to an embodiment of the present invention, the material of the coating film is selected according to the wavelength of light emitted from the light source in the optical-electricity encoder.
A second aspect of the present invention provides a photoelectric encoder, including: according to the fixed grating, the movable grating, the photosensitive unit, the light source and the signal processing unit, wherein the movable grating is fixed on the shaft through the bearing and can rotate along with the shaft, the fixed grating is located on the surface of the photosensitive unit, and the photosensitive unit is coupled with the signal processing unit.
According to the utility model discloses a scheme can produce the wave form of high quality sinusoidal signal, guarantees the sinusoidal nature that is used for the source signal of electron segmentation, improves the precision of electron segmentation, solves absolute formula photoelectric encoder and satisfies the difficult problem that high resolution and size are little simultaneously.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic diagram of a grating principle according to an exemplary embodiment of the present invention.
Fig. 2 is a schematic diagram of a sinusoidal code track transmittance according to an exemplary embodiment of the present invention.
Fig. 3 is a schematic diagram of single-turn coding according to an exemplary embodiment of the present invention.
Fig. 4 is a structural diagram of an optical-electrical encoder according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
As used herein, the terms "first," "second," and the like may be used to describe elements of exemplary embodiments of the invention. These terms are only used to distinguish one element from another element, and the inherent features or order of the corresponding elements and the like are not limited by the terms. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms, such as those defined in commonly used dictionaries, are to be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Those skilled in the art will understand that the devices and methods of the present invention described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. Features illustrated or described in connection with one exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, detailed descriptions of related known functions or configurations are omitted to avoid unnecessarily obscuring the technical points of the present invention. In addition, the same reference numerals refer to the same circuits, modules or units throughout the description, and repeated descriptions of the same circuits, modules or units are omitted for brevity.
The utility model provides a decide grating for photoelectric encoder decides grating is including a plurality of absolute code tracks of arranging in proper order and at least one sinusoidal code track that is located optical center both sides. The fixed grating absolute code channel and the sine code channel are light transmission parts in the optical glass. The relation between the number N of absolute code channels and the number of scribed lines of the sinusoidal code channels is N =2 n . The other parts of the fixed grating are light-tight, and a sine code channel is arranged on the fixed grating, so that the sine light-transmitting area is changed into the positive half period of the trigonometric function along with the rotation of the movable grating, the electric signal after photoelectric conversion is changed into the corresponding positive half period of the trigonometric function, and the trigonometric function can be changed by the sine function, has sine property, and takes the electric signal with sine property as the source signal for electronic subdivision, thereby effectively improving the electronic subdivision precision of the photoelectric encoder, and further improving the electronic subdivision precision of the photoelectric encoderAccuracy of the photoelectric encoder.
Fig. 1 is a schematic diagram of a fixed grating principle according to an exemplary embodiment of the present invention.
As shown in fig. 1, the fixed grating is composed of an absolute code channel 1, an absolute code channel 2, an absolute code channel 3, an absolute code channel 4, an absolute code channel 5, an absolute code channel 6, an absolute code channel 7, an absolute code channel 8, and a sinusoidal code channel. The absolute code channels 1-8 are used for generating single-circle absolute codes, and the absolute codes of each single circle correspond to unique position information; and the sinusoidal code channel is used for generating a sinusoidal signal, which corresponds to one period in the absolute code of each single turn. Because of the fixed grating and the movable grating, the absolute code track and the sinusoidal code track are in pairs and are respectively positioned on the fixed grating and the movable grating.
According to one or more embodiments of the present invention, the absolute code tracks are arranged in sequence as required without determining the requirements; the number N of absolute code channels has no direct relation with the number of sinusoidal code channels, and the relation with the number N of ruled lines of sinusoidal code channels is N =2 n (ii) a If the number of the sinusoidal code channels is multiple, the sinusoidal code channels are staggered by 90 degrees in phase and are positioned on two sides of the optical center. For example: the sinusoidal code channels are divided into 4 parts, the labels are 1, 2, 3, and 4, the 4 parts are staggered by 90 ° according to the phase, for example, the corresponding phase of each sinusoidal code channel is: 1 is sin,2 is-cos, 3 is cos, and 4 is-sin.
As shown in FIG. 1, the absolute tracks 1-8 are arranged in a staggered manner in the longitudinal direction of the fixed grating. Therefore, the mutual influence among all the absolute code channels can be avoided, and all the absolute code channels are dispersedly arranged on two sides of the geometric center of the fixed grating instead of being intensively arranged on a line. According to one or more embodiments of the present invention, fig. 1 only shows the case where the absolute code track is 8, and the number of the absolute code track and the sinusoidal code track may be plural according to the needs of the photoelectric encoder.
According to the utility model discloses a produced sinusoidal signal of sinusoidal code track is the cornerstone of electron subdivision, and is right through interpolation method or interpolation operation (be arctangent usually) sinusoidal signal handles to reach the mesh that improves encoder resolution ratio. By adding the sine code channel, a trigonometric function (for example, 90 degrees) with a preset phase difference with the light transmission area change trigonometric function of the original sine code channel is obtained, and interpolation operation is performed through the two trigonometric functions, so that the operation result is more accurate. According to the utility model discloses an one or more embodiment, the utility model discloses utilize the sine code track to obtain the sine and cosine signal of ideal, through trigonometric function interpolation operation, can promote segmentation precision.
In fig. 1, a is a partially enlarged reference symbol of the fixed grating, and according to one or more embodiments of the present invention, for example, when a is 100, 100.
Fig. 2 is a schematic diagram of a sinusoidal code track transmittance according to an exemplary embodiment of the present invention.
As shown in fig. 2, the sinusoidal code channel adopts a gradient color coating to change the light transmittance of the window of the sinusoidal code channel, the relationship between the light transmittance I (vertical axis) and the window width X (horizontal axis) is shown in fig. 2, and the light transmittance changes sinusoidally relative to the window width; because the light of the photoelectric encoder is collimated light and the light intensity is a constant value P, when the moving grating of the encoder moves, the output photocurrent can be calculated by the following formula:
i(Δx)＝P*I*S(Δx)
wherein S is the light transmission area, and Deltax is the movement variable of the movable grating relative to the fixed grating; in addition, because the light transmittance I is a sine function, the output light current I is a sine signal, and because the light transmittance can be continuously changed by the gradient color coating, discrete errors can not be generated, the sine of a source signal for electronic subdivision is ensured, and the subdivision precision is improved. The plating material may include any one of aluminum oxide, hafnium oxide, and aluminum fluoride.
According to one or more embodiments of the present invention, the fixed grating is made of optical glass and is a carrier for scribing lines of each sinusoidal code channel and each absolute code channel, and the window on the grating is a scribing line.
Fig. 3 is a schematic diagram of single-turn coding according to an exemplary embodiment of the present invention.
As shown in fig. 3, the light source passes through a slit disc of the photoelectric encoder, that is, a slit disc composed of a movable grating and a fixed grating, and a three-bit encoding schematic diagram obtained after the light source is detected by a photodetector is obtained through the photoelectric encoder: 000. 001, 011, 010,100,101,110,111, the 8 absolute code values.
Fig. 4 is a structural diagram of an optical-electrical encoder according to an exemplary embodiment of the present invention.
As shown in fig. 4, the structural member includes a shaft, a bracket, and a bearing; the movable grating is fixed on the shaft and rotates along with the shaft; the LED (light source) is fixed on the bracket, and the fixed grating is positioned on the surface of the photosensitive unit; the photosensitive unit is welded on the PCB, and the PCB comprises a signal processing circuit and is fixed on the bracket.
According to the utility model discloses an one or more embodiment, the utility model discloses a photoelectric encoder includes: the fixed grating shown in figure 1, movable grating, photosensitive unit, light source, signal processing unit and the structure including shaft, support and bearing, wherein, the movable grating is fixed on the shaft and rotates along with the shaft, the fixed grating is located on the surface of the photosensitive unit, the photosensitive unit is coupled with the signal processing unit, and the signal processing unit is fixed on the support.
The utility model provides a produce sinusoidal signal's grating surely, its sinusoidal code track window adopts the gradual change look coating film to the luminousness that changes light becomes sinusoidal distribution, guarantees the sinusoidal nature that is used for the source signal of electron segmentation, improves segmentation precision, solves absolute formula photoelectric encoder's high resolution and the little difficult problem of size.
The drawings referred to above and the detailed description of the invention, which are given as examples of the invention, serve to explain the invention without limiting the meaning or scope of the invention as described in the claims. Accordingly, modifications may be readily made by those skilled in the art from the foregoing description. In addition, one skilled in the art may delete some of the constituent elements described herein without deteriorating performance, or may add other constituent elements to improve performance. Further, the order of the steps of the methods described herein may be varied by one skilled in the art depending on the environment of the process or apparatus. Therefore, the scope of the present invention should be determined not by the embodiments described above but by the claims and their equivalents.
While the invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (10)
1. A fixed grating, the fixed grating is used for a photoelectric encoder, and is characterized in that: the fixed grating comprises:
the optical system comprises a plurality of absolute code channels and at least one sinusoidal code channel, wherein the absolute code channels and the sinusoidal code channels are sequentially arranged;
wherein the relation between the number N of the absolute code channels and the number of the scribed lines of the sinusoidal code channels is N =2 n 。
2. The constant grating as claimed in claim 1, wherein:
the sinusoidal code channels are multiple, and the multiple sinusoidal code channels are sequentially staggered by 90 degrees in phase.
3. The constant grating as claimed in claim 1, wherein:
wherein the absolute code track is used to generate a single-turn absolute code corresponding to unique position information, an
Wherein the sinusoidal code channel is further used for generating a sinusoidal signal corresponding to one period in the absolute coding of each single turn.
4. The constant grating as claimed in claim 1, wherein: wherein, the light transmittance of the sine code channel is changed by adopting a gradient coating film.
5. The fixed grating of claim 4, wherein:
when the moving grating of the photoelectric encoder moves, the photocurrent output by the sinusoidal code channel is as follows: i (Δ x) = P × I × S (Δ x),
wherein, P is the light intensity of the light source, S is the light transmission area of the sine code channel, and Delta x is the movement variable of the movable grating relative to the fixed grating; and I is the light transmittance of the sinusoidal code channel.
6. The constant grating as claimed in claim 1, wherein: the fixed grating is made of optical glass, and the optical glass is a carrier for scribing the sine code channel and the absolute code channel.
7. The optical grating of claim 6, wherein:
wherein the scribed line is a window on the optical glass.
8. The fixed grating of claim 2, wherein:
the resolution of the photoelectric encoder is improved by carrying out interpolation operation on a sine function with a plurality of sine code channels with changed light transmission areas.
9. The fixed grating of claim 4, wherein:
the material of the coating is selected according to the wavelength of light emitted by a light source in the photoelectric encoder.
10. An optical-electrical encoder, characterized by: the method comprises the following steps: the fixed grating, the movable grating, the photosensitive unit, the light source, the signal processing unit according to any one of claims 1 to 9,
the movable grating is fixed on the shaft through a bearing and can rotate along with the shaft, the fixed grating is positioned on the surface of the photosensitive unit, and the photosensitive unit is coupled with the signal processing unit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202222802263.7U CN218765338U (en) | 2022-10-24 | 2022-10-24 | Fixed grating and photoelectric encoder |
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| CN202222802263.7U CN218765338U (en) | 2022-10-24 | 2022-10-24 | Fixed grating and photoelectric encoder |
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| CN218765338U true CN218765338U (en) | 2023-03-28 |
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