CN114527528B - Blazed grating processing method and optical variable device based on blazed grating - Google Patents
Blazed grating processing method and optical variable device based on blazed grating Download PDFInfo
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- CN114527528B CN114527528B CN202210120725.9A CN202210120725A CN114527528B CN 114527528 B CN114527528 B CN 114527528B CN 202210120725 A CN202210120725 A CN 202210120725A CN 114527528 B CN114527528 B CN 114527528B
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- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
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- G02B5/1847—Manufacturing methods
- G02B5/1852—Manufacturing methods using mechanical means, e.g. ruling with diamond tool, moulding
Abstract
The present invention relates to a method of processing a blazed grating and an optical variable device based on the blazed grating. A processing method of blazed grating comprises the following steps: applying elliptical vibration to the cutter, wherein the period of the elliptical vibration is divided into a front half process and a rear half process; in the first half, the cutter performs cutting processing on the workpiece, and material removal is performed; in the latter half, the tool performs plastic forming processing on the workpiece to form a blazed surface of the blazed grating. According to the method for processing the blazed grating, by applying the elliptical vibration mode to the cutter and dividing the elliptical vibration period into the first half and the second half, one blazed grating can be processed on each vibration period, so that efficient processing of the blazed grating is realized, a composite processing mode of cutting and plastic forming is realized on each vibration period, and rapid forming of the blazed surface of the blazed grating is promoted.
Description
Technical Field
The invention relates to the technical field of micro-nano optical processing, in particular to a processing method of blazed gratings and an optical variable device based on the blazed gratings.
Background
Blazed gratings, also known as echelle gratings, are a special form of reflective or transmissive diffraction grating designed to produce maximum diffraction efficiency at a particular diffraction order. This means that most of the optical power will be at the design diffraction order while minimizing the power of the other orders.
Mechanical scoring is the most traditional method of producing blazed gratings and has a very long history. Although the technology of manufacturing master plane diffraction gratings is widely used in the prior art, the photoetching technology and the laser holographic processing are widely used. However, due to the problems of too high processing cost of the photolithography technology, very limited processing capability of laser holographic processing on high-density diffraction gratings, etc., it is difficult to process gratings containing special groove patterns, such as infrared blazed gratings, etc. Therefore, the traditional machining mode of mechanical scribing is still needed for manufacturing the high-density blazed grating. The core idea of manufacturing the diffraction grating by mechanical scribing mainly comes from the processing of a squaring machine. The work platform drives the grating blank to do indexing motion according to grating constant on the special grating ruling machine, and the fixed cutter bridge provided with the diamond ruling cutter does reciprocating motion. The mechanical scribing method has the characteristics of easy control of the groove shape of the grating, but has the problem of lower processing efficiency when the scale of the grating is reduced to near visible light.
Disclosure of Invention
Accordingly, it is necessary to provide a method for processing a blazed grating and an optical variable device using the blazed grating, which solve the problem of low processing efficiency in the conventional method for manufacturing the blazed grating.
In one aspect, a method for processing a blazed grating includes the steps of:
applying elliptical vibration to the cutter, wherein the period of the elliptical vibration is divided into a front half way and a rear half way;
in the first half, the cutter performs cutting processing on a workpiece to remove materials;
in the latter half, the tool performs plastic forming processing on the workpiece to form a blazed surface of the blazed grating.
According to the method for processing the blazed grating, by applying elliptical vibration to the cutter and dividing the elliptical vibration period into the first half and the second half, one blazed grating can be processed on each vibration period, so that efficient processing of the blazed grating is realized; in the first half of each vibration period, the cutter performs cutting processing on the workpiece to remove materials; in the latter half of each vibration period, the cutter performs plastic forming processing on the workpiece to form a blazed surface of the blazed grating, so that a composite processing mode of cutting and plastic forming is realized on each vibration period, rapid forming of the blazed surface of the blazed grating is promoted, and the processing efficiency is higher compared with that of the traditional manufacturing method of the blazed grating.
In one embodiment, a nominal cutting speed is applied to the cutter while elliptical vibration is applied, a plurality of blazed gratings are processed, and a plurality of blazed gratings of the same specification within one pixel length form a blazed grating group, wherein the direction of the nominal cutting speed is the same as the front side of the cutter.
In one embodiment, the processing method of the blazed grating further includes the following steps:
processing a plurality of blazed grating groups to form a first blazed grating column by using the elliptical vibration and the first nominal cutting speed along the first cutting direction;
the cutter rotates by taking the normal line of the base plane of the workpiece as an axis;
the cutter moves to generate a first feeding amount;
and processing a plurality of blazed grating groups along a second cutting direction by using the elliptical vibration and the second nominal cutting speed to form a second blazed grating column.
In one embodiment, the processing method of the blazed grating further includes the following steps:
the tool movement produces a first amount of translation,
and superposing the first nominal cutting speed along the first cutting direction by using the elliptical vibration, and processing a plurality of first blazed grating columns which are parallel to each other to form a first blazed grating array.
In one embodiment, the processing method of the blazed grating further includes the following steps:
the tool produces a second amount of translation,
and superposing a second nominal cutting speed along a second cutting direction by using the elliptical vibration, and processing a plurality of second blazed grating columns which are parallel to each other to form a second blazed grating array.
In one embodiment, the angle of rotation of the tool about the normal to the base plane of the workpiece is 180 °, the first cutting direction is opposite to the second cutting direction, the blazed direction of the first blazed grating row is a first blazed direction, the blazed direction of the second blazed grating row is a second blazed direction, and the first blazed direction and the second blazed direction are symmetrical about the normal to the base plane of the workpiece.
In one embodiment, the angle by which the tool rotates about the normal to the base plane of the workpiece is 90 °, the first cutting direction and the second cutting direction are orthogonal to each other, the blazed direction of the first blazed grating row is a first blazed direction, the blazed direction of the second blazed grating row is a second blazed direction, and the first blazed direction and the second blazed direction are orthogonal to each other.
In one embodiment, the magnitude of the first nominal cutting speed and the magnitude of the second nominal cutting speed can be varied in units of pixels.
In one embodiment, the tool is a diamond tool.
In one embodiment, the direction angle of the track of the elliptical vibration is 0-90 degrees.
On the other hand, the optical variable device based on the blazed grating comprises a workpiece, wherein a first blazed grating row and a second blazed grating row are arranged on the workpiece in a row, the first blazed grating row comprises a plurality of blazed grating groups which are arranged in a row and have the blazed direction of the first blazed direction, the second blazed grating row comprises a plurality of blazed grating groups which are arranged in a row and have the blazed direction of the second blazed direction, a plurality of blazed gratings with the same specification in one pixel length form one blazed grating group, and the first blazed direction and the second blazed direction are mutually orthogonal or are mutually symmetrical by taking the normal line of the base plane of the workpiece as an axis.
In the above-described blazed grating-based optical variable device, the first blazed grating row and the second blazed grating row are provided in a row on the work piece, and the first blazed direction and the second blazed direction are orthogonal to each other or symmetrical to each other with respect to the normal line of the base plane of the work piece, and by rotating the blazed grating-based optical variable device by 180 ° or 90 °, changing the viewing direction by 180 ° or 90 °, viewing in the first blazed direction and the second blazed direction, respectively, two groups of pictures can be observed. The device can couple two groups of information to the same blazed grating-based optical variable device, and can decouple the information on the same plane by changing the observation direction or rotating the placement position of a workpiece, so that the diversity and richness of information transmission are expanded, and the device can be applied to the fields of laser decoupling, anti-counterfeiting marking, encryption transmission and the like.
In one embodiment, the workpiece is provided with a plurality of rows of the first blazed grating rows and a plurality of rows of the second blazed grating rows, the first blazed grating rows are arranged in rows to form a first blazed grating array, the second blazed grating rows are arranged in rows to form a second blazed grating array, and the first blazed grating array and the second blazed grating array are adjacently arranged or are mutually alternated.
In one embodiment, the grating pitches of the blazed grating groups of the first blazed grating columns are the same or different; and/or the number of the groups of groups,
the grating pitches of the blazed grating groups of the second blazed grating columns are the same or different.
In one embodiment, the grating depths of different ones of the blazed grating groups of the first blazed grating columns are the same or different; and/or the number of the groups of groups,
the grating depth of the different blazed grating groups of the second blazed grating columns is the same or different.
Drawings
FIG. 1 is a diagram of basic parameters of a blazed grating according to an embodiment of the method for processing a blazed grating;
FIG. 2 is a schematic diagram of a method for processing a blazed grating according to an embodiment;
FIG. 3 is a schematic diagram of a blazed grating group processing method according to an embodiment;
fig. 4 is a schematic structural view of an optical variable device based on blazed gratings of the first embodiment;
fig. 5 is a view of the visual effect of the blazed grating-based optically variable device of the first embodiment, as seen from the first blazed direction;
fig. 6 is a view showing the visual effect of the blazed grating-based optically variable device of the first embodiment as viewed from the second blazed direction;
fig. 7 is a schematic structural diagram of an optical variable device based on blazed gratings according to a second embodiment;
fig. 8 is a view of the visual effect of the blazed grating-based optically variable device of the second embodiment, as seen from the first blazed direction;
fig. 9 is a view of the visual effect of the blazed grating-based optically variable device of the second embodiment as seen from the second blazed direction.
In the figure:
1. a cutter; 2. nominal cutting speed; 3. an elliptical vibration trajectory; 4. a direction angle; 5. a workpiece; 6. a nominal depth of cut direction; 7. a semi-major axis; 8. a semi-minor axis; 9. nominal depth of cut; 10. a rear corner; 11. a raw surface; 12. synthesizing a processing track; 13. blazed gratings; 14. blaze angle; 15. a first half process; 16. the second half; 17. grating spacing;
100. the blazed grating based optically variable device of the first embodiment; 101. a white light irradiation direction; 102. a base plane normal direction of the workpiece; 103. a first feed direction; 104. a first feed amount; 105. the length of one pixel; 110. a first blazed grating array; 111. a first blazed grating column; 120. a second blazed grating array; 121. a second blazed grating column; 131. a first cutting direction; 132. a second cutting direction; 141. a first blaze direction; 142. a second blaze direction;
200. the blazed grating based optically variable device of the second embodiment; 201. a white light irradiation direction; 202. a base plane normal direction of the workpiece; 203. a first feed direction; 204. a first feed amount; 205. a second feed direction; 206. a second feed amount; 210. a first blazed grating array; 211. a first blazed grating column; 220. a second blazed grating array; 221. a second blazed grating column; 231. a first cutting direction; 232. a second cutting direction; 241. a first blaze direction; 242. and a second blaze direction.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.
In one aspect, the present application provides a method for processing a blazed grating according to an embodiment, including the following steps:
and S01, applying elliptical vibration to the cutter, wherein the period of the elliptical vibration is divided into a first half and a second half.
And S02, in the first half, cutting the workpiece by using a cutter to remove the material.
And S03, in the latter half, the cutter performs plastic forming processing on the workpiece to form a blazed surface of the blazed grating.
First, referring to fig. 1, fig. 1 shows basic parameters of a blazed grating. Blazed gratings mainly comprise blazed grating planes and blazed surfaces. Further, the included angle between the blazed surface and the blazed grating plane is the blazed angle, and the included angle between the normal line of the blazed surface and the normal line of the blazed grating plane is equal to the blazed angle. The normal direction of the blazed surface is the blazed direction of the blazed grating. The distance between two adjacent blazed grating groups is the grating spacing.
Specifically, referring to fig. 2, fig. 2 is a schematic diagram illustrating a processing method of the blazed grating according to the present embodiment. By applying elliptical vibration to the tool 1, an elliptical vibration locus 3 of the tool 1 is obtained. Wherein the central position of the elliptical vibration locus 3 is determined according to the nominal depth of cut 9 during processing of the blazed grating. Typically, the nominal depth of cut direction 6 is directed towards the blazed grating plane.
Further, the elliptical vibration path 3 of the tool 1 is generated by a vibration generating device based on resonance or non-resonance. The frequency of elliptical vibration is determined by the ability of the vibration generating device. Preferably, in the present embodiment, the elliptical vibration frequency of the tool 1 is 2000Hz, enabling efficient processing of blazed gratings. In other embodiments, the Gao Tuoyuan vibration frequency may be increased to a higher level depending on the capabilities of the actual vibration generating device, without limitation.
Further, the cutter 1 in the embodiment is a diamond cutter, and may be a natural diamond material or an artificial diamond material, and the diamond material has a high hardness, so that the processing effect of the blazed grating can be ensured.
Optionally, the radius of the front end of the cutter 1 is 500um-700um, the front angle is 0-5 degrees, and the rear angle 10 is 5-15 degrees. Wherein the front angle of the tool 1 is the included angle between the front plane of the tool 1 and the normal of the base plane of the workpiece 5; the relief angle 10 of the tool 1 is the angle between the cutting surface of the tool 1 and the raw surface 11, and the blazed angle 14 of the blazed grating is usually equal to the relief angle 10 of the tool 1. Preferably, the front end radius of the tool 1 in the present embodiment is 600um, so that sub-micron grating fabrication can be achieved. The front angle of the cutter 1 is 0 degree, the strength of the cutter 1 in the processing process is ensured, the component force generated in the processing process is reduced as much as possible, and the input of a power source is efficiently utilized. The relief angle 10 of the cutter 1 is 10 degrees, and the applicant verifies through a large number of experiments that when the relief angle 10 of the cutter 1 is 10 degrees, the blazed angle 14 of the processed blazed grating has a stable value, and the stable value approaches to the relief angle value of the cutter 1, so that the surface profile of the processed blazed grating is smoother. The foregoing specific parameter values for the tool 1 are merely illustrative, and in other embodiments, parameters such as the front end radius, the front angle, the rear angle 10, etc. of the tool 1 can be adaptively adjusted according to actual requirements.
Alternatively, the direction angle 4 of the elliptical vibration track 3 is 0 ° to 90 °. Preferably, in the present embodiment, the elliptical vibration locus 3 is a positive ellipse whose direction angle 4 is 90 °. The direction angle 4 is the angle between the semi-major axis 7 of the ellipse and the nominal cutting speed 2. Proved by a great number of experiments of applicant, the direction angle 4 of the elliptical vibration track 3 has important influence on the generation of the blazed grating surface, and has stronger correlation with the intensity of scattered white light. In the present embodiment, the semimajor axis 7 of the elliptical vibration track 3 is 3um and the semiminor axis 8 is 1um. When the direction angle 4 of the elliptical vibration track 3 is 0 °, the diffraction intensity of the blazed grating reaches a maximum value. By setting the direction angle 4 of the elliptical vibration track 3 to 90 degrees, the achievable range of the grating spacing 17 in the blazed grating group can be enlarged, and the effects of simplifying the track path, reducing disturbance variables in the blazed grating processing experiment process and facilitating analysis of the processing process of the workpiece 5 can be achieved. Of course, the direction angle 4 of the elliptical vibration track 3 is not limited to 90 °, and in other embodiments, the direction angle 4 of the elliptical vibration track 3 may be adjusted according to actual machining requirements.
Further, referring to fig. 3, fig. 3 is a schematic diagram showing a processing method of a blazed grating according to the present embodiment. The nominal cutting speed 2 is applied while elliptical vibration is applied to the cutter 1, a plurality of blazed gratings are formed, and a plurality of blazed gratings of the same specification within one pixel length form one blazed grating group. Further, the nominal cutting speed 2 is oriented in the same direction as the front side of the tool 1. The elliptical vibration path 3 is applied to the tool 1 together with the nominal cutting speed 2, and the resultant machining path 12 forming the tool 1 is a resultant machining path 12 approximating a spiral line.
Further, in some embodiments, a tool servo technique is used for the tool 1 to achieve control of the nominal cutting speed 2 and the nominal cutting depth 9 in pixels. Since the nominal cutting speed 2 needs to be determined together with the vibration frequency according to the blazed grating pitch 17 of the blazed grating group to be processed, i.e. the nominal cutting speed 2 is equal to the product of the blazed grating pitch 17 and the vibration frequency. By varying the nominal cutting speed 2, the blazed grating pitch 17 of the blazed grating groups is adjusted, whereby the blazed grating groups of different pixels can be caused to reflect different colors. When processing a plurality of blazed grating groups, different blazed grating groups can be processed by adjusting the cutting parameters of the cutter 1 according to the characteristics of the required images, so as to meet various requirements.
Specifically, the work 5 using the processing method of the blazed grating of the present embodiment may be a metal, a resin, or other nonmetallic material. Therefore, the processing method using the blazed grating of the present embodiment can be applied to a variety of different application scenarios.
According to the method for processing the blazed grating, by applying elliptical vibration to the cutter 1 and dividing the elliptical vibration period into the first half 15 and the second half 16, one blazed grating can be processed on each vibration period, so that efficient processing of the blazed grating is realized; in the first half 15 of each vibration cycle, the tool 1 performs cutting processing on the workpiece 5 to perform material removal; in the latter half 16 of each vibration period, the tool 1 performs plastic forming processing on the workpiece 5 to form a blazed surface of the blazed grating, so that a composite processing mode of cutting and plastic forming is realized on each vibration period, rapid forming of the blazed surface of the blazed grating is promoted, and the processing efficiency is higher compared with the traditional manufacturing method of the blazed grating.
In some embodiments, the method of processing a blazed grating further comprises the steps of:
s11, processing a plurality of blazed grating groups to form a first blazed grating array by using elliptical vibration and superposition of a first nominal cutting speed along a first cutting direction.
Specifically, the blaze direction of the first blazed grating column is the first blaze direction. Specifically, the first blazed grating columns are arranged in a straight line shape. Further, the first nominal cutting speed can be changed by taking pixels as a unit, so that the grating spacing and the number of gratings between each first blazed grating group are different among a plurality of processed adjacent first blazed grating groups, different reflection colors can be observed when the observation direction is positioned in the first blazed direction according to the diffraction principle of light, in practical application, the colors of images formed by the first blazed grating columns can be enriched, and the information transmission quantity and the picture quality are improved.
Further, step S11 may further include the steps of:
s110, moving the cutter to generate a first translation amount; and superposing the first nominal cutting speed along the first cutting direction by using elliptical vibration, and processing a plurality of first blazed grating columns parallel to each other to form a first blazed grating array. Further, the first shift amount is two pixels long, so that a plurality of first blazed grating columns arranged in a straight line are uniformly spaced apart from each other.
S12, rotating the cutter by taking the normal line of the base plane of the workpiece as an axis.
Specifically, the base plane of the work piece and the base plane of the blazed grating group are parallel to each other. The cutting direction of the tool is changed by rotating the tool with the normal line of the base plane of the workpiece as an axis, so that the movement track of the tool is changed.
S13, moving the cutter to generate a first feeding amount.
Specifically, the first feed amount is the length of one pixel. The length of a pixel is determined by the size and resolution of the workpiece, and the length of a pixel can be adaptively adjusted according to specific imaging requirements. More specifically, the first feed direction of the generation of the first feed amount is orthogonal to the first nominal cutting speed direction.
S14, processing a plurality of blazed grating groups along a second cutting direction by using elliptical vibration to overlap a second nominal cutting speed to form a second blazed grating column.
Specifically, the blaze direction of the second blazed grating column is the second blaze direction. Specifically, the second blazed grating columns are arranged in a straight line shape. Since the tool passes through rotation about the normal of the base plane of the workpiece, the second cutting direction is different from the first cutting direction. So that the second blaze direction of the second blaze grating column is also different from the first blaze direction. Further, the second nominal cutting speed can be adjusted by taking pixels as a unit, so that the grating spacing and the number of the second blazed grating groups are different among a plurality of processed adjacent second blazed grating groups, different reflection colors can be observed when the observation direction is positioned in the first blazed direction according to the diffraction principle of light, and in practical application, the colors of images formed by the second blazed grating columns can be enriched, and the information transmission quantity and the picture quality are improved.
Further, step S14 may further include the steps of:
s140, moving the cutter to generate a second translation amount; and superposing a second nominal cutting speed along a second cutting direction by using elliptical vibration, and processing a plurality of second blazed grating columns which are parallel to each other to form a second blazed grating array. Further, the second shift amount is two pixels long, so that a plurality of second blazed grating columns arranged in a straight line are uniformly spaced apart from each other. In some embodiments, the second blazed grating columns and the first blazed grating columns which are respectively arranged in a straight line are mutually and alternately distributed.
The method of processing the blazed grating in the above embodiment will be described in detail below with specific examples.
First embodiment
Specifically, referring to fig. 4 in combination, the processing method of the blazed grating of the first embodiment includes the following steps:
s11-1, a plurality of blazed grating groups are processed along the first cutting direction 131 by using elliptical vibration to overlap the first nominal cutting speed to form a first blazed grating column 111.
S12-1, rotating the cutter by 180 degrees by taking the normal line of the base plane of the workpiece as an axis.
S13-1, the cutter moves to generate a first feed 104.
S14-1, a plurality of blazed grating groups are processed along the second cutting direction 132 by using elliptical vibration to overlap the second nominal cutting speed to form a second blazed grating column 121.
In the blazed grating processing method of the first embodiment, the angle by which the tool rotates about the normal line of the base plane of the workpiece in the foregoing embodiment is mainly thinned is 180 °. Thus, the blazed direction of the second blazed grating row 121 processed by the blazed grating processing method of the first embodiment and the blazed direction of the first blazed grating row 111 are symmetrical to each other about the normal line of the base plane of the work piece, and the second cutting direction 132 and the first cutting direction 131 are disposed opposite to each other. Thus, two sets of information can be coupled to the first blazed grating array 111 and the second blazed grating array 121 located on the same workpiece, respectively, and the information of the first blazed grating array 111 and the second blazed grating array 121 can be decoupled by rotating the workpiece or rotating the observation direction by 180 °.
Second embodiment
Specifically, referring to fig. 7 in combination, the processing method of the blazed grating of the second embodiment includes the following steps:
s11-2, a plurality of blazed grating groups are processed along the first cutting direction 231 by using elliptical vibration to overlap the first nominal cutting speed to form a first blazed grating column 211.
S12-2, rotating the cutter by 90 degrees by taking the normal line of the base plane of the workpiece as an axis.
S13-2, the cutter moves to generate a first feed 204.
S14-2, a plurality of blazed grating groups are processed along the second cutting direction 232 by using elliptical vibration to overlap the second nominal cutting speed to form a second blazed grating column 221.
In the blazed grating processing method according to the second embodiment, the tool in the foregoing embodiment is mainly thinned to be rotated by 90 ° about the normal line of the base plane of the workpiece. Thus, the blazed direction of the second blazed grating row 221 processed by the blazed grating processing method of the second embodiment is orthogonal to the blazed direction of the first blazed grating row 211, and the second cutting direction 232 is orthogonal to the first cutting direction 231. Thus, two sets of information can be coupled to the first blazed grating array 211 and the second blazed grating array 221 located on the same workpiece, respectively, and the information of the first blazed grating array 211 and the second blazed grating array 221 can be decoupled by rotating the workpiece or rotating the observation direction by 90 °.
Specifically, in step S14-2, the method further comprises the following steps:
s14-20, the tool movement generates a second feed 206. Specifically, the feeding direction of the second feeding amount 206 is orthogonal to the direction of the second nominal cutting speed, so that the plurality of second blazed grating groups can be arranged in a "straight" shape. Further, the distance of the second feed amount 206 is one pixel long.
On the other hand, based on the foregoing method for processing a blazed grating, the present application further provides an optical variable device based on a blazed grating according to an embodiment, including a workpiece, on which a first blazed grating row and a second blazed grating row are arranged in a row, where the first blazed grating row includes a plurality of blazed grating groups arranged in a row and having a first blazed direction, and the second blazed grating row includes a plurality of blazed grating groups arranged in a row and having a second blazed direction, where a plurality of blazed gratings of the same specification within a pixel length form one blazed grating group, and the first blazed direction and the second blazed direction are orthogonal to each other or are symmetrical with each other about a normal line of a base plane of the workpiece.
An optically variable device (Optically Variable Device, OVD) is a security device capable of displaying a variety of information channels. In conventional optically variable devices, OVDs are typically fabricated using one-dimensional gratings. However, since the direction of the one-dimensional grating is fixed, the one-dimensional grating has the problem of limited decoupling in the process of decoupling information, which results in lower visual quality of the OVD.
In the above-described blazed grating-based optical variable device, the first blazed grating row and the second blazed grating row are provided in a row on the work piece, and the first blazed direction and the second blazed direction are orthogonal to each other or symmetrical to each other with respect to the normal line of the base plane of the work piece, and by rotating the blazed grating-based optical variable device by 180 ° or 90 °, changing the viewing direction by 180 ° or 90 °, viewing in the first blazed direction and the second blazed direction, respectively, two groups of pictures can be observed. The device can couple two groups of information to the same blazed grating-based optical variable device, and can decouple the information on the same plane by changing the observation direction or rotating the placement position of a workpiece, so that the diversity and richness of information transmission are expanded, and the device can be applied to the fields of laser decoupling, anti-counterfeiting marking, encryption transmission and the like.
The blazed grating based optically variable device in the above embodiments is described in detail below with specific examples.
Referring to fig. 4, the optical variable device 100 based on blazed gratings of the first embodiment is based on the processing method of blazed gratings of the foregoing first embodiment, and includes a workpiece, on which a first blazed grating row 110 and a second blazed grating row 120 are arranged in a row, the first blazed grating row 110 includes a plurality of blazed grating groups arranged in a row and having a first blazed direction 141, the second blazed grating row 120 includes a plurality of blazed grating groups arranged in a row and having a blazed direction 142, and a plurality of blazed gratings of the same specification within a pixel length form one blazed grating group, and the first blazed direction 141 and the second blazed direction 142 are axisymmetric to each other with respect to the base plane normal 102 of the workpiece. Referring to fig. 5 to 6, two sets of images are respectively obtained by decoupling when the blazed grating based optically variable device 100 according to the first embodiment is rotated 180 ° or the viewing angle is rotated 180 °.
The blazed grating-based optical variable device 100 of the first embodiment described above can observe two sets of pictures by rotating the blazed grating-based optical variable device by 180 ° or changing the viewing direction by 180 °, respectively, in the first blazed direction 141 and the second blazed direction 142. The device can couple two groups of information to the same blazed grating-based optical variable device, and can decouple the information on the same plane by changing the observation direction or rotating the placement position of a workpiece, so that the diversity and richness of information transmission are expanded, and the device can be applied to the fields of laser decoupling, anti-counterfeiting marking, encryption transmission and the like.
Referring to fig. 7, the blazed grating-based optical variable device 200 of the second embodiment is based on the processing method of the blazed grating of the foregoing second embodiment, and includes a workpiece, on which a first blazed grating row 210 and a second blazed grating row 220 are arranged in rows, the first blazed grating row 210 includes a plurality of blazed grating groups arranged in a row and having a first blazed direction 241, the second blazed grating row 220 includes a plurality of blazed grating groups arranged in a row and having a second blazed direction 242, and a plurality of blazed gratings of the same specification within a pixel length form one blazed grating group, and the first blazed direction 241 and the second blazed direction 242 are mutually orthogonal. Referring to fig. 8 to 9, two sets of images are respectively decoupled when the blazed grating-based optically variable device 200 according to the second embodiment is rotated by 90 ° or the viewing angle is rotated by 90 °.
The blazed grating-based optically variable device 200 according to the second embodiment can observe two sets of pictures by rotating the blazed grating-based optically variable device by 90 ° or changing the viewing direction by 90 °, respectively, in the first blazed direction 241 and the second blazed direction 242. The device can couple two groups of information to the same blazed grating-based optical variable device, and can decouple the information on the same plane by changing the observation direction or rotating the placement position of a workpiece, so that the diversity and richness of information transmission are expanded, and the device can be applied to the fields of laser decoupling, anti-counterfeiting marking, encryption transmission and the like.
Further, the blazed grating based optically variable device 100 based on the aforementioned first embodiment is identical to the blazed grating based optically variable device 200 of the second embodiment, in some embodiments the grating pitch of each blazed grating group of the first blazed grating array is identical; in some embodiments, the grating pitch of each blazed grating group of the first blazed grating array is different. Further, in some embodiments, the grating pitch of each blazed grating group of the second blazed grating array is the same; in some embodiments, the grating pitch of each blazed grating group of the second blazed grating array is different. Therefore, when the first blazed direction or the second blazed direction is observed, different colors can be observed in the first blazed grating group or the second blazed grating group respectively, and thus richer and more various image information can be presented.
Further, the blazed grating based optically variable device 100 based on the aforementioned first embodiment is identical to the blazed grating based optically variable device 200 of the second embodiment, in some embodiments the grating depth of each blazed grating group of the first blazed grating array is identical; in some embodiments, the grating depth of each blazed grating group of the first blazed grating array is different. Further, in some embodiments, the grating depth of each blazed grating group of the second blazed grating array is the same; in some embodiments, the grating depth of each blazed grating group of the second blazed grating array is different. Wherein the grating depth is the perpendicular distance between the lowest extremity of the blazed grating and the unprocessed plane on the workpiece. Therefore, the imaging effect of the optical variable device based on the blazed grating can have a certain three-dimensional attribute, and the transferred image information can have more dimensions. In general, in order to ensure processing efficiency during processing, the grating depth of each blazed grating group of the first blazed grating array is the same, and the grating depth of each blazed grating group of the second blazed grating array is the same.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (8)
1. A processing method of blazed gratings is characterized by comprising the following steps:
applying elliptical vibration to a cutter and applying a nominal cutting speed at the same time so as to process a plurality of blazed gratings, wherein the plurality of blazed gratings with the same specification in one pixel length form a blazed grating group, and the direction of the nominal cutting speed is the same as the front side of the cutter; the period of the elliptical vibration is divided into a first half and a second half;
in the first half, the cutter performs cutting processing on a workpiece to remove materials;
in the latter half, the cutter performs plastic forming processing on the workpiece to form a blazed surface of the blazed grating;
wherein, still include the following step:
processing a plurality of blazed grating groups to form a first blazed grating column by using the elliptical vibration and the first nominal cutting speed along the first cutting direction;
the cutter rotates by taking the normal line of the base plane of the workpiece as an axis;
the cutter moves to generate a first feeding amount;
and processing a plurality of blazed grating groups along a second cutting direction by using the elliptical vibration and the second nominal cutting speed to form a second blazed grating column.
2. The method of processing a blazed grating according to claim 1, further comprising the steps of:
the tool movement produces a first amount of translation,
and superposing the first nominal cutting speed along the first cutting direction by using the elliptical vibration, and processing a plurality of first blazed grating columns which are parallel to each other to form a first blazed grating array.
3. The method of processing a blazed grating according to claim 1, further comprising the steps of:
the tool produces a second amount of translation,
and superposing a second nominal cutting speed along a second cutting direction by using the elliptical vibration, and processing a plurality of second blazed grating columns which are parallel to each other to form a second blazed grating array.
4. A method of processing a blazed grating according to any one of claims 1 to 3, wherein the tool is rotated by 180 ° about the normal to the base plane of the work, the first cutting direction is opposite to the second cutting direction, the blazed direction of the first blazed grating row is a first blazed direction, the blazed direction of the second blazed grating row is a second blazed direction, and the first blazed direction and the second blazed direction are symmetrical to each other about the normal to the base plane of the work.
5. A method of processing a blazed grating according to any one of claims 1 to 3, wherein the tool is rotated by 90 ° about a normal to a base plane of the work, the first cutting direction and the second cutting direction are orthogonal to each other, the blazed direction of the first blazed grating row is a first blazed direction, the blazed direction of the second blazed grating row is a second blazed direction, and the first blazed direction and the second blazed direction are orthogonal to each other.
6. A method of processing a blazed grating according to any one of claims 1-3, wherein the magnitude of the first nominal cutting speed and the magnitude of the second nominal cutting speed are variable in pixels.
7. A method of processing a blazed grating according to claim 6, wherein the tool is a diamond tool.
8. A method of processing a blazed grating according to claim 6, wherein the elliptical vibration trajectory has a direction angle of 0 ° to 90 °.
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