RU205773U1 - Compact diffraction phase microscope for use in conjunction with a smartphone - Google Patents

Abstract

The device belongs to the fields of quantitative phase and holographic microscopy and can be used to determine the morphology of blood cells by digital processing of data and present the results in the form of three-dimensional diagrams and histograms (the number of erythrocytes, leukocytes and platelets, hematocrit and erythrocyte indices (MCV, RDW)) ... A compact diffraction phase microscope for use in conjunction with a smartphone contains a sequentially placed power source, a laser, a test strip, a diffraction grating, a first lens, a spatial filter, is equipped with a means of attachment to a smartphone and a third lens placed between the second lens and the camera and the lens of the smartphone, spatial the filter contains a first-order diffraction window and a low-pass filter. The technical result of the claimed device is to increase its manufacturability by reducing the size and ensuring the possibility of using it with a smartphone. 2 c.p. f-ly, 2 dwg

Description

The device belongs to the fields of quantitative phase and holographic microscopy and can be used to determine the morphology of blood cells by digital processing of data and present the results in the form of three-dimensional diagrams and histograms (the number of erythrocytes, leukocytes and platelets, hematocrit and erythrocyte indices (MCV, RDW)) ...

Similar devices are known from the prior art, for example, a hematology analyzer with a stirring device operating with whole blood (see RU 2359242 C2, publ. 20.06.2009). The analyzer is designed to supply and process tubes in the "test tube by test tube" mode. It contains a stirring device configured to receive a test tube with blood and stir the contents of this tube with blood in accordance with the selected mixing method, controls associated with the stirring device and configured to control stirring of the contents of the test tube with blood under controlled conditions in accordance with certain parameters, while the control means contains a programming tool that has the ability to program the duration of mixing in the mixing device, a selection means made with the possibility of automatically taking a blood sample from a test tube with blood, the contents of which are premixed using the mixing device, and transferring the blood sample to the analysis unit ...

The disadvantages of the analogue are that it does not have sufficient compactness.

The closest analogue, according to the applicant, is a diffraction phase microscope (US 8837045 B2, publ. 09/16/2014), in which the light collected from a sample illuminated by a source incoherent in time is diffracted to the first order, and either zero or first order low pass filtered in the plane of the Fourier transform. Low-pass filtering of the first-order diffracted beam at multiple wavelengths obtains a quantitative phase image of the sample with spectral and spatial resolution.

The disadvantages of the analogue are that the processing of information from the specified phase microscope requires additional equipment, which complicates and slows down the process of obtaining the analysis result.

The technical result of the claimed device is to increase its manufacturability by reducing the size and ensuring the possibility of using it with a smartphone, which allows the device to be used in non-laboratory conditions for primary blood analysis without training the user and / or the subject, while observing safety precautions when working with whole blood.

The claimed technical result is achieved by creating a compact diffraction phase microscope for use with a smartphone, containing sequentially placed power source, laser, test strip, diffraction grating, first lens, spatial filter, while it is equipped with a means of attachment to the smartphone and a third lens placed between the second lens and the camera and the smartphone lens, the spatial filter contains a first-order diffraction window and a low-pass filter.

In a particular embodiment, the means for attaching to a smartphone is made in the form of a clip.

The claimed utility model is illustrated by the following figures:

FIG. 1 schematically shows the device of a diffraction phase microscope.

FIG. 2 is a top view of the spatial filter.

The positions in FIG. 1, 2 mean the following:

1 - diffraction phase microscope;

2 - camera and smartphone lens;

3 - power supply;

4 - laser;

5 - test strip;

6 - diffraction grating;

7 - the first lens;

8 - spatial filter;

9 - second lens;

10 - third lens;

11 - smartphone lens;

12 - smartphone camera;

13 - low-pass filter;

15 - transmission window of the first order of diffraction;

15 - focal distance of the first lens;

16 - focal distance of the second lens.

The device belongs to the fields of quantitative phase and holographic microscopy and can be used to determine the morphology of blood cells by digital processing of data and presenting the results in the form of three-dimensional diagrams and histograms (the number of erythrocytes, leukocytes and platelets, hematocrit and erythrocyte indices (MCV, RDW)) with the possible subsequent transfer of data to clinics and medical institutions via a mobile network.

The device in the housing is installed in the center of the smartphone camera and its optical lens system, thus, the optical axis of the device is exposed and attached to it with a fastening means, mainly a clip.

The device is powered by a power source. The whole blood test strip is clipped into a slot located between the laser source and the diffraction grating. The spatial filter is calibrated prior to each application against the maximum zero diffraction order intensity.

The transparent window of the test strip is illuminated by a plane wave from a laser source. When a light wave passes through the sample, spatial phase shifts of the wave occur - spatial phase modulation, the values of which are determined by the local thickness of the object and the refractive indices of the object and the environment. As a result of this modulation, an object field is formed, including the scattered and unscattered components. The diffraction grating decomposes the object field into diffraction orders. To form an interference image, a spatial filter is used (Fig. 2), which completely passes the 1st diffraction order and the unscattered component of the object field in the zero diffraction order. In the rear focal plane of the second objective, the superposition and interference of the unscattered quasi-plane wave and the obliquely incident wave field of the object image occurs. The rear focal plane of the second lens is mated to the front focal plane of the micro lens of the 4-f system, which consists of the micro lens and the smartphone lens system. A smartphone camera (matrix photo detector) records streaming images of interference patterns.

The distribution of light intensity in the interference pattern in the plane of the matrix photodetector can be represented in the following simplified form:

- распределения интенсивности объектного и опорного полей, соответственно;

- период интерференционных полос, M - увеличение изображения, даваемое оптической системой,

- период дифракционной решетки; α - угол, определяющий ориентацию решетки относительно рядов пикселей фотодетектора;

- фазовый набег, возникающий при прохождении волны через объект.where the x, y coordinates are oriented along the rows of the photodetector pixels,

- distribution of the intensity of the object and reference fields, respectively;

is the period of the interference fringes, M is the magnification of the image given by the optical system,

- period of the diffraction grating; α is the angle that determines the orientation of the grating relative to the rows of pixels of the photodetector;

- phase incursion arising from the passage of a wave through an object.

можно использовать выражениеWith a plane illuminating wave and sufficiently smooth spatial optical inhomogeneities of the object for

you can use the expression

- пространственный рельеф поверхности объекта,

- пространственное распределение показателя преломления объекта,

- показатель преломления окружающей среды.where (is the wavelength of the light used,

- spatial relief of the object surface,

- the spatial distribution of the refractive index of the object,

is the refractive index of the environment.

The resulting system of interference fringes in the image of an object is, in fact, a system of carrier bands of a hologram structure. Numerical processing of such a structure, for example, using direct and inverse Fourier transforms and spatial filtering of the hologram spectrum, allows one to reconstruct the spatial distribution of phase shifts of the object field and, accordingly, spatial variations in the optical thickness of the object. From the calculation of the thickness of each individual blood cell of streaming images, data statistics are generated for further calculation of the number of erythrocytes, leukocytes and platelets, hematocrit values, erythrocyte indices (MCV, RDW) and presentation of the results in the form of three-dimensional diagrams. If necessary, the data can be transferred to clinics by means of mobile communication.

A number of technical requirements:

, где

- числовая апертура первой линзы интерференционного модуля. При этом поперечный размер

разрешаемого системой объекта, например, эритроцита в мазке крови, должен, по крайней мере, в два раза превышать период решетки,

. В этом случае дифракционные порядки объектного поля в задней фокальной плоскости объектива не будут перекрываться, и возможна эффективная пространственная фильтрация объектного светового поля. В интерференционном изображении объекта, образующемся в задней фокальной плоскости второй линзы модуля будет формироваться примерно 3 интерференционных полосы.1. For spatial filtering of wave fields that have experienced diffraction by a diffraction grating, it is necessary that the first diffraction order fall into the aperture of the first lens of the system. This is fulfilled provided that the lattice period

, where

is the numerical aperture of the first lens of the interference module. In this case, the transverse dimension

an object resolved by the system, for example, an erythrocyte in a blood smear, must be at least twice the lattice period,

... In this case, the diffraction orders of the object field in the rear focal plane of the lens will not overlap, and effective spatial filtering of the object light field is possible. In the interference image of the object, formed in the rear focal plane of the second lens of the module, approximately 3 interference fringes will be formed.

которых равен

, где

- поперечное увеличение системы, определяемое отношением фокусных расстояний линз,

. Это требование эквивалентно выполнению условия Найквиста, которое для записи цифровой голограммы можно представить в виде:

, где

- период расположения пикселей матричного фотодетектора. С учетом фазовых вариаций поля изображения объекта, вызывающих вариации периода полос, это неравенство следует записать в виде

.2. For the device to work, it is necessary that the smartphone camera matrix resolves the carrier interference fringes of the image, the average period

which is

, where

- lateral magnification of the system, determined by the ratio of the focal lengths of the lenses,

... This requirement is equivalent to the fulfillment of the Nyquist condition, which for recording a digital hologram can be represented as:

, where

- the period of the arrangement of the pixels of the matrix photodetector. Taking into account the phase variations of the object image field, which cause variations in the period of the stripes, this inequality should be written in the form

...

, при

.1. Combining the requirements in items 1 and 2 leads to a generalized condition for optical spatial filtering of diffracted fields and recording a digital hologram in the following form:

, at

...

мкм). Это повышает износостойкость дифракционного модуля при замене тест-полосок. Однако и покровное стекло и дифракционная решетка вносят сферические аберрации, что снижает разрешающую способность данной оптической системы.2. To protect the surface of the diffraction grating, the latter is installed in the device with the glass side to the test strips and a cover glass is installed after the diffraction grating (

μm). This increases the durability of the diffraction module when changing test strips. However, both the cover glass and the diffraction grating introduce spherical aberrations, which reduces the resolution of this optical system.

Claims (3)

1. A compact diffraction phase microscope for use with a smartphone, containing a sequentially placed power supply, a laser, a test strip, a diffraction grating, a first lens, a spatial filter, characterized in that it is equipped with a means of attachment to a smartphone and a third lens placed between the second lens and camera and smartphone lens, the spatial filter contains a first-order diffraction window and a low-pass filter. 2. A compact diffraction phase microscope according to claim 1, characterized in that the means of attachment to the smartphone is made in the form of a clip. 3. Compact diffraction phase microscope according to claim 1, characterized in that the transmission window of the first diffraction order is made in the form of a set of spheres of the same diameter, made at the same distance from the center of the zero order, the divergence between the centers of the two extreme spheres is not more than 30 degrees.

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