RU157473U1 - OPTICAL-ELECTRONIC DEVICE FOR QUALITY CONTROL OF DIFFRACTION AND HOLOGRAPHIC ELEMENTS - Google Patents

Abstract

1. An optical-electronic device for controlling the quality of diffraction and holographic elements, which includes an emitter, two optical channels combined into a single optical head and including focusing optics, a beam splitter in the form of a cube prism, and two pickup sensors for receiving different images of the element being monitored, the optical axis of the first channel is perpendicular to the optical axis of the second channel and is optically coupled to a cube-prism, characterized in that the emitter is LED, the first optical channel recording microiso The image consists of the following elements installed along the single optical axis of the channel: the first lens in the focal plane of which the controlled element is located, a cube-prism, the second lens in the focal plane of which the image pickup sensor is installed in the form of a photodetector for digital recording of microzones of the microzone of the controlled element; the second optical channel for recording macro images consists of sequentially installed along its optical axis of its lens and its image pickup sensor in the form of its photodetector digital registration of macro images located in the plane of the best lens setting of the second channel; there is also a digital operator unit for receiving, displaying and processing digital images of channels, first of all, for controlling the quality of an element by means of correlation comparison of a micro image of a controlled microzone of an element and a digital block of a correlation filter synthesized using a set of images of several

Description

Technical field

The utility model relates to the field of creating optoelectronic devices that allow quality control of diffraction and holographic optical elements (DOEs and GOEs) of various types.

State of the art

Known devices for quality control, diagnosis and identification of diffraction and holographic optical elements (DOE and GOE). Consider devices that are quite close in technical essence to the claimed utility model.

A known quality control device for various types of GOE according to Japanese patent JP 3339426 (B2) "QUALITY INSPECTION DEVICE" (IPC B41F 33/14; G01N 21/89; G01N 21/892; G06T 1/00; G06T 7/00, publ. 2002 -10-28), including for simultaneous inspection of part of the hologram and another part of the control object with one device by providing one or more illumination sources of the controlled hologram in addition to an ordinary light source for determining quality. Illumination source of the controlled hologram light incident on the hologram layer at a given angle of inclination to produce a reproducible image of the hologram suitable for monitoring the hologram recorded in the hologram layer by the image capturing camera. An ordinary light source illuminates the surface of the printed material, with the exception of the hologram layer, or the substrate at an angle of inclination to give an image of the brightness field or dark field, most suitable for controlling the print surface or base using an image capture camera. Image data collected sequentially is stored in memory. The stored images are synthesized and output to the display means as a two-dimensional image. The quality determination tool processes the images of the reference image of the inspected object, which is not damaged and previously taken as multi-gradation data, and compares and compares the image data with the data of the reference image according to the density level of each pixel to determine the quality.

The device has the following disadvantages and limitations:

1) The device does not have the ability to register macro images of diffraction and hologram optical elements.

2) The lack of a visual optical guidance channel for specific control microzones required for a human operator.

3) Working with images, and not with their spectra, leads to significant errors when comparing with a reference threshold value.

A device is known, described in European patent No. EP 0412316 A2 "Authenticy identifying system for information storage cards" (G03H 1/30; G06K 19/16; G03H 1/26; G06K 19/14, publ. 02.13.1991). This device is intended to identify the authenticity of data storage cards, where the identification area is a hologram, diffraction grating or a set of diffraction gratings with different frequencies (that is, different types of DOE and GOE). The device is equipped with a laser radiation source illuminating the hologram, as well as a set of radiation detectors located in the direction of propagation of radiation diffracting on the hologram.

The device has the following disadvantages and limitations:

1) The device does not have the ability to register macro images of diffraction and hologram optical elements.

2) The lack of a visual optical guidance channel for specific control microzones required for a human operator.

As the closest analogue, the closest in technical essence to the claimed utility model device for hologram verification according to US patent No. 6832003 “Method and apparatus for reading and verifying holograms” (IPC G06K 7/10; G06K 9/00; G07F 7/08; G03H 1/22; G06K 19/06; G06K 9/76, publ. 14.12.2004). The device is designed to work with various types of optical elements and DOEs and includes a laser emitter, two optical channels combined into a single optical head and including focusing optics, two beam splitters in the form of cube prisms and two pickup sensors for receiving different images of the element under control, the optical axis of the first channel perpendicular to the optical axis of the second channel and optically coupled to one of the cube prisms (see FIG. 3 and description text to FIG. 3 from US patent No. 6832003).

The device has the following disadvantages and limitations:

1) The device does not have the ability to register macro images of diffraction and hologram optical elements.

2) The lack of a visual optical guidance channel for specific control microzones required for a human operator.

Disclosure of a utility model The objective of a utility model is to accelerate and simplify the quality control process of DOE and GOE by using the optical channel of macro images of various sections of the controlled DOE and GOE together with an automated linear system of the optical head of the device for its quick prompt guidance by the operator to areas with controlled microzones.

The technical result is achieved in that the optical-electronic device for controlling the quality of diffraction and holographic elements includes an LED emitter, two optical channels combined into a single optical head and including focusing optics, a beam splitter in the form of a cube prism, and two pickup sensors for receiving different images of the element under control. Moreover, the optical axis of the first channel is perpendicular to the optical axis of the second channel and is optically coupled to the cube prism. In this case, the first optical micro-image recording channel consists of the following elements installed along the single optical axis of the channel: the first lens, in the focal plane of which the element to be controlled is located, a cube-prism, and the second lens, in the focal plane of which an image receiving sensor is installed in the form of a digital photodetector microzones of the microzone of the controlled element. The second optical channel for recording macro images consists of sequentially installed along its optical axis of its lens and its image pickup sensor in the form of its photodetector digital registration of macro images located in the plane of the best lens installation of the second channel. There is also a digital operator unit for receiving, displaying and processing digital images of channels, first of all, for controlling the quality of an element by correlating a micro image of a monitored element microzone and a digital correlation filter stored in a digital block synthesized using a set of images of several microzones of a reference element. In addition, the optical head is equipped with an automated linear displacement system, including a two-coordinate displacement unit and an autofocus unit along the optical axis of the first micro-image registration channel. The specified linear displacement system is connected via an electronic control unit to a digital operator unit with the ability to quickly, according to macro images of the second optical channel, guide the optical head to areas with controlled microzones.

Mainly used a linear increase in the first channel of microimages in the range of 40 ... 60 ^x , and a linear increase in the second channel of macroimages in the range of 4 ... 6 ^x .

The LED emitter is mainly a set of LEDs mounted around the optical axis of the first optical channel at an angle to the normal to the plane of the element being monitored.

The difference between the quality control of DOE and GOE in the claimed utility model from the prototype is also that in the proposed device, in the plane of the radiation receiver, micro images of certain microzones of the element under control are recorded, followed by computer analysis of the spectra of these images, while the principle of the control’s operation is based on spatial frequency spectra (PES) of recorded microimages of DOE and GOE sections. In the prototype, spatial spectra are already formed and recorded in the second optical channel (picture of the diffraction distribution).

List of figures

FIG. 1 - Functional diagram of an optoelectronic device for quality control of DOE and GOE.

Utility Model Implementation

In FIG. 1 is a functional diagram of a quality control device for DOE and HOE 2, consisting of two optical channels separated by a cube-prism 5. The controlled element 3 with a surface DOE and GOE 2 is illuminated by a backlight system 1, which is a set of LED emitters. The first optical micro-image channel includes a micro-lens 4, a cube-prism 5, a tube lens 6, a photodetector 7, consisting of a radiation matrix receiver 8 and an electronic unit 9. The second macro-optical optical channel (guidance channel) consists of a micro-lens 4, a cube prisms 5 and a photodetector 10, consisting of a lens 11, a matrix receiver 12 and an electronic unit 13. Digital video signals from the photodetector devices 7 and 10 are fed to a digital unit (computer) 14 of the operator for receiving, displaying and processing digital signals even images of channels. The optical head has the ability to move using an automated linear displacement system consisting of an electronic control unit 15, a two-coordinate displacement block 16 along the x-y axes and an autofocus unit 17 along the z axis. Block 15 is connected with blocks 14, 16 and 17. The emitter 1 is a set of LEDs (8 ... 20 LEDs illuminating the element under study with white light) mounted around the optical axis at an angle to the normal to the plane of the element 3 being monitored, which can be additionally fixed optional a fixture for fixing and aligning (for example, a magnetic table, not shown in FIG. 1).

The device operates as follows. A fixed controlled element 3 with DOE and GOE 2 is highlighted by a set of emitters 1 at an angle to the normal to the plane of element 3. A micro lens 4 and a tube lens 6 form an enlarged micro image in the plane of the sensitive elements of the matrix radiation detector (MPI) 8 of the photodetector (FPU) 7. The micro image is recorded MPI 8 is converted in the electronic unit 9 into a digital code and recorded in the memory of computer 14. In the computer, as part of the quality control of the element, a correlation comparison of the microimage is made microzones of the controlled element 2 and the synthesized correlation filter stored in the computer 14. The correlation filter is synthesized according to the algorithm using a set of images of several microzones of the reference element. In this case, an analysis of the spectra of these images was used and the principle of the control’s operation is based on the analysis of spatial frequency spectra (PSP) of recorded microimages of DOE and GOE sections. The results of correlation comparison give the desired quality assessment of DOE and GOE.

A micro lens 4 and an additional lens 11 of the second optical guidance channel together form a macro image in a larger angular field. The macro image is recorded by the MPI 12 (second FPU), converted into a digital code in the electronic unit 13, transferred to the computer's memory 14 and restored to the computer monitor for operational monitoring by a human operator.

To point to each of the controlled areas of the element, the device is equipped with a block of linear two-coordinate movement 16 at x, y coordinates and an autofocus block 17 along the vertical coordinate z, which are actuated by the electronic control unit for positioners 15.

A prototype device provides control of elements up to 300 × 300 mm ^{2 in} size containing DOE-GOE, has the ability to quickly point to the required control areas using a second optical guidance channel, and the ability to automatically move in the horizontal plane of the optical head along two linear mutually perpendicular coordinates in the range ± 150 mm and automated movement for autofocus vertically in the range of ± 25 mm.

This prototype device will be used at MSTU. N.E. Bauman during the creation of an experimental model of an optical-electronic scanner for operational control of the authenticity of protective holograms on government documents as part of the research work "Development of methods for analyzing holographic images of protective holograms on documents and an optical-electronic scanner for their authentication and identification" according to State Order No. 3.1426.2014K of the Ministry education and science of the Russian Federation. The results of the research can also be used to verify the authenticity and identification of bank cards, various travel documents in the transport infrastructure, various pass cards of state and commercial institutions, as well as on many other documents of legal entities and individuals.

The implementation of the utility model can also provide the ability to control the quality of not only ready-made DOEs and GOEs, but also the quality of the original master matrices used in the hot stamping technology for duplicating elements, which will reduce the percentage of rejects produced DOE-GOE.

Claims (3)

1. An optical-electronic device for controlling the quality of diffraction and holographic elements, which includes an emitter, two optical channels combined into a single optical head and including focusing optics, a beam splitter in the form of a cube prism, and two pickup sensors for receiving different images of the element being monitored, the optical axis of the first channel is perpendicular to the optical axis of the second channel and is optically coupled to a cube-prism, characterized in that the emitter is LED, the first optical channel recording microiso The image consists of the following elements installed along the single optical axis of the channel: the first lens in the focal plane of which the controlled element is located, a cube-prism, the second lens in the focal plane of which the image pickup sensor is installed in the form of a photodetector for digital recording of microzones of the microzone of the controlled element; the second optical channel for recording macro images consists of sequentially installed along its optical axis of its lens and its image pickup sensor in the form of its photodetector digital registration of macro images located in the plane of the best lens setting of the second channel; there is also a digital operator unit for receiving, displaying and processing digital images of channels, first of all, for monitoring the quality of an element by correlating a micro image of a monitored element microzone and a digital correlation filter stored in a digital block synthesized using a set of images of several microzones of a reference element; in addition, the optical head is equipped with an automated linear displacement system, including a two-coordinate displacement unit and an autofocus unit along the optical axis of the first micro-image registration channel, and the specified linear displacement system is connected via an electronic control unit to a digital operator unit with the possibility of prompt, by macro images of the second optical channel, operator guidance optical head to areas with controlled microzones. 2. The device according to p. 1, characterized in that the linear increase in the first channel in the range of 40 ... 60 ^x , and a linear increase in the second channel in the range of 4 ... 6 ^x . 3. The device according to claim 1, characterized in that the LED emitter includes a set of LEDs mounted around the optical axis at an angle to the normal to the plane of the element being monitored.

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