Aberration detection device and method based on mobile phone light source

Abstract

The present invention discloses an aberration detection device and method based on a mobile phone light source, the device comprising: a mobile phone light source (1), an optical beam expansion projection system (2) and an optical camera (4); wherein the mobile phone light source (1) is used to project a stripe pattern onto the optical beam expansion projection system; the optical beam expansion projection system (2) is used to amplify the spatial size of the stripe spot pattern projected by the mobile phone light source (1), and irradiate the amplified stripe pattern onto the surface of a component to be tested (3); the optical camera (4) is used to collect the light intensity signal after the component to be tested (3) reflects or transmits the corresponding stripe pattern. The aberration detection device based on a mobile phone light source provided by an embodiment of the present invention can use a mobile phone as a light source, and realize aberration detection of the surface of the component to be tested by projecting a stripe pattern onto the optical beam expansion projection system, and detect the aberration of a device that is several times larger than the size of a mobile phone display screen.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and more specifically to an aberration detection device and method based on a mobile phone light source. Background Art

[0002] In order to effectively detect the laser performance of components in the optical system, it is necessary to fully analyze the aberration of the components and make improvements to the components according to the actual situation to ensure that the beam quality will not degrade. Therefore, it is necessary to effectively detect the wavefront aberration of the optical components in each link of the laser system, such as the wavefront aberration of the laser gain module and the real-time detection of the aberration of the optical lens.

[0003] When measuring the aberration of large-aperture and aspherical surface, the Hartmann sensor is mainly used to detect the wavefront information of the optical system to be measured or the optical components in the optical system, or the interferometer is used to detect the phase difference of the optical system to be measured or the optical components in the optical system. Usually, the two aberration detection devices, Hartmann sensor and interferometer, include a light source and a beam expansion or contraction device coaxial with a set of light sources, and the two are packaged as a whole, so the volume of these two aberration detection devices is very large. In addition, both detection devices use a standard light source to illuminate the surface of the optical system to be measured or the optical component to be measured, and then analyze the light beam reflected or transmitted by the optical system to be measured or the optical component to be measured to detect the wavefront aberration. However, in these two detection devices, the standard light source is usually a parallel light source with a large aperture and high-precision surface, and the manufacturing difficulty of this parallel light source is very large, the process is complicated, and there is a problem of high cost.

[0004] When using the above two detection devices to test some compact, lightweight and miniaturized optical systems, due to the large size of the detection device, it is difficult to align the center position of the detection light source with the optical system by adjusting the relative position of the detection device and the optical system to be tested. For example, the height of the detection device is very high, while the height of the optical system to be tested is very low, and both are fixed on a laboratory table. The light beam emitted by the detection device cannot irradiate or cover the entire surface of the optical system to be tested, and due to the large size of the detection device, it is difficult to fix the detection device at other positions. Moreover, sometimes when detecting an optical component in an optical system, since the relative positions of the components in the optical system are fixed and the distance between the two components is very small, it is difficult for the detection device to be placed between the two components to detect a single component. Therefore, there is an urgent need for a detection device with a simple structure and convenient use.

[0005] In recent years, a software configurable optical test system (SCOTS) has been rapidly developed in the field of surface aberration detection. SCOTS is a software configurable optical test system based on fringe reflection technology or phase deflection method. It has important applications in large-aperture component surface detection, aspheric optical lens processing and aberration detection. SCOTS has a wider application space and has the following advantages: 1) It does not require a large-aperture light source. The experimental principle and device are simple. The system only consists of the components to be tested, an LCD display and a computer with a built-in camera; 2) Low cost. It does not require a large-aperture parallel light source and Hartmann sensor. Large-aperture parallel light sources and Hartmann sensors are difficult to process and very expensive; 3) The test is flexible and efficient. Testing using SCOTS technology does not require precise and strict optical path adjustment to be tested, and can quickly test the components to be tested. However, this method currently requires the use of an LCD display whose physical size is larger than the size of the component to be tested. When the size of the LCD display is fixed, it is impossible to efficiently and flexibly test the aberration of the component to be tested whose aperture is larger than the LCD display. Moreover, this method can currently only measure reflective devices. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] The technical problem to be solved by the present invention is to provide an aberration detection device and method based on a mobile phone light source. The device can use a mobile phone light source to project a stripe pattern without using a large-aperture, expensive standard parallel light source, thereby realizing aberration detection of transmission or reflection type large-aperture devices using a small-size mobile phone light source.

[0008] (II) Technical solution

[0009] In order to solve the above technical problems, the first aspect of the present invention provides a detection device based on a mobile phone light source, comprising a mobile phone light source, an optical beam expansion projection system and an optical camera. The mobile phone light source is used to project a stripe pattern onto the optical beam expansion projection system; the optical beam expansion projection system is used to expand the spatial size of the stripe pattern projected by the mobile phone light source according to a preset multiple, and irradiate the expanded stripe pattern onto the surface of the component to be tested; the optical camera is used to collect the light intensity signal after the component to be tested reflects or transmits the stripe pattern projected onto its own surface.

[0010] The aberration detection device based on the mobile phone light source provided in the embodiment of the present invention uses the mobile phone light source to project a fringe pattern to the optical beam expansion projection system. After the fringe pattern is expanded by the optical beam expansion projection system, the expanded fringe pattern is obtained. The expanded fringe pattern is projected onto the surface of the component to be tested, and the light intensity signal transmitted or reflected by the component to be tested is received by the optical camera. The device can calculate the wavefront aberration distribution on the component to be tested by calculating the phase of the fringe pattern emitted by the mobile phone light source and the phase of the light intensity signal collected by the optical camera corresponding to the fringe pattern. There is no need to use traditional large-aperture wavefront detectors and interferometers as light sources, which reduces the requirements for the surface accuracy of the illumination light source. The system structure is simple, and there is no need for precise and strict optical path adjustment of the component to be tested, which reduces the system complexity and the difficulty of optical path adjustment.

[0011] Optionally, a mobile phone light source is used as a detection light source to project a fringe pattern device.

[0012] Specifically, the mobile phone light source can be one of the current thin film field effect transistor (TFT) screen, in-plane switching screen (IPS) screen, liquid crystal display (LCD) screen, upgraded LCD (superLCD) screen or organic light-emitting diode (OLED).

[0013] Optionally, the above-mentioned device also includes: a calculation module, which is used to obtain the phase difference of the component to be tested based on the real phase of the component to be tested corresponding to the light intensity signal and the ideal phase corresponding to the ideal fringe pattern, and calculate the aberration of the component to be tested based on the phase difference; the ideal fringe pattern is generated based on the fringe pattern emitted by the mobile phone light source and the three-dimensional information of the component to be tested.

[0014] Optionally, the ideal fringe pattern is generated based on the expanded fringe pattern and three-dimensional information of the component to be tested, and the expanded fringe pattern is a fringe pattern obtained by expanding the spatial dimensions of the fringe pattern emitted by the mobile phone light source by a preset multiple.

[0015] In an optional embodiment, an ideal stripe pattern is obtained based on the expanded stripe pattern and three-dimensional information of the component to be tested, including: simulating the projection of the expanded stripe pattern onto a standard component of the same type as the component to be tested, simulating the collection of an ideal light intensity signal after reflection or transmission of the expanded stripe pattern by the standard component, and restoring the ideal stripe pattern based on the ideal light intensity signal.

[0016] Optionally, the aberration of the component under test is obtained according to the phase difference, including: obtaining the offset between the real fringe pattern restored by the real light intensity signal and the same pixel point in the ideal fringe pattern according to the phase difference; calculating the slope of the pixel point corresponding to the offset relative to the transmission direction of the light incident on the pixel point according to the offset; obtaining the deformation amount of the component under test at the corresponding position of the pixel point according to the slope at each pixel point; the aberration of the component under test is composed of the deformation amounts of all pixel points of the fringe pattern restored by the light intensity signal.

[0017] Optionally, each of the stripe patterns is composed of a pixel array, each row of pixels is divided into a stripe group, or each column of pixels is divided into a stripe group, the grayscale values ​​of pixels belonging to the same stripe group are the same, and along the direction of arrangement of the stripe groups, the grayscale values ​​of all the stripe groups constituting the pixel array are sinusoidally or cosine distributed.

[0018] Optionally, the mobile phone light source 1 is used to project two groups of stripe patterns to the optical beam expansion projection system in sequence; the number of stripe patterns in each group is 4, the arrangement direction of the stripes in the 4 stripe patterns in each group is the same, and the latter stripe pattern in each group of stripe patterns is formed by moving the previous stripe pattern by π / 2 along the arrangement direction of the stripe group; in the 2 groups of stripe patterns, the 4 stripe patterns in the second group are formed by rotating the 4 stripe patterns in the first group by 90 degrees one by one.

[0019] Optionally, the optical beam expansion projection system is a single optical element, and the single optical element is arranged on the same optical axis as the mobile phone light source; or, the optical beam expansion projection system includes multiple optical elements, one of the multiple optical elements is arranged on the same optical axis as the mobile phone light source, and all of the optical elements are arranged on the same optical axis in sequence.

[0020] Alternatively, the optical beam expansion projection system includes a first lens and a second lens arranged on a common optical axis, the first lens and the mobile phone light source are arranged on the same optical axis, the second lens and the first lens have the same focus, preferably, the size of the first lens is greater than or equal to the size of the stripe pattern emitted by the mobile phone light source, and the second lens is a lens with a large curvature, so as to achieve beam expansion of the light beam passing through the second lens. When the second lens is a lens with a large curvature, the magnification of the stripe pattern can be higher.

[0021] It can be understood that in the light beam expansion projection system set in this embodiment, multiple optical components are arranged on the same optical axis. The multiple optical components may not be on the same horizontal line, but multiple optical components need to be arranged on the same optical axis, so that the parameters can be optimized according to the needs, and the volume of the light beam projection system can be flexibly adjusted, thereby improving the scope of application of the detection device. Moreover, the multiple optical components are arranged on the same optical axis, and the physical size of the component to be tested can be less than or equal to or several times larger than the stripe pattern generated by the mobile phone light source, so that the mobile phone light source with a size smaller than the component to be tested can be used to illuminate the component to be tested from the experimental device.

[0022] Optionally, the light source of the mobile phone is one of the current thin film field effect transistor screen, plane switching screen, liquid crystal display screen or organic light emitting diode screen.

[0023] Optionally, the optical beam expansion projection system includes a lens group or a reflector group or a combination of a lens and a reflector; wherein the lens group is a cylindrical mirror, a spherical mirror, an aspherical mirror or any combination of a cylindrical mirror, a spherical mirror and an aspherical mirror; the reflector group is a cylindrical mirror, a spherical mirror, an aspherical mirror or any combination of a cylindrical mirror, a spherical mirror and an aspherical mirror.

[0024] Optical cameras are mainly used to convert light signals into electrical signals, so as to detect and record the light intensity information of the fringe pattern after transmission and reflection of the components to be tested.

[0025] Optionally, the optical camera is an optical camera containing a linear array charge coupled device (CCD) detector and / or a linear array complementary metal oxide semiconductor (CMOS) detector.

[0026] Optionally, the surface of the component to be tested can transmit or reflect the stripe pattern. In other words, the component to be tested is a transmissive device with optical distortion, or the component to be tested is a reflective device with optical distortion.

[0027] According to a second aspect of the present invention, there is provided an aberration detection method based on a mobile phone, comprising: calculating the real phase of a component to be tested according to a real light intensity signal, the real light intensity signal is collected after the component to be tested reflects or transmits a beam-expanded fringe pattern, the beam-expanded fringe pattern is formed by expanding the fringe pattern emitted by a mobile phone light source according to a preset multiple; calculating an ideal phase, the ideal phase is the phase of an ideal fringe pattern; the ideal fringe pattern is generated based on the fringe pattern emitted by the mobile phone light source and three-dimensional information of the component to be tested; obtaining the phase difference of the component to be tested according to the phase of the component to be tested and the ideal phase; and obtaining the phase difference of the component to be tested according to the phase difference.

[0028] It is understandable that in some technologies, a detection device is first used to detect components that are considered ideal, and during the detection process, an ideal stripe pattern is obtained by reflection from the ideal component. Then, the same detection device is used to detect the component to be tested, and during the detection process, a real stripe pattern is obtained by reflection from the component to be tested. Then, the aberration of the component to be tested is calculated based on the ideal stripe pattern and the real stripe pattern. However, this technology has the following defects: (1) Two different components are used for detection twice, resulting in low efficiency; (2) It is difficult to find an ideal component, and after being used several times, an ideal component is easily worn out and becomes a non-ideal component, which also leads to low detection efficiency; (3) The ideal component may also have very small distortion, which will lead to inaccurate aberration calculation when calculating the aberration.

[0029] The ideal aberration obtained by pure theoretical calculation in the present application is closer to the real aberration. Moreover, the present application only uses a detection device to detect the components to be tested. There is no need to select "ideal components" or detect ideal components, thereby improving the detection accuracy and efficiency of the aberration of the components to be tested.

[0030] Optionally, obtaining the phase difference of the component under test according to the phase difference includes: obtaining the offset between the real stripe pattern restored by the real light intensity signal and the same pixel point in the ideal stripe pattern according to the phase difference; calculating the slope of the pixel point corresponding to the offset relative to the transmission direction of the light incident on the pixel point according to the offset; obtaining the deformation amount of the component under test at the corresponding position of the pixel point according to the slope at each pixel point; the aberration of the component under test is composed of the deformation amounts of all pixel points of the stripe pattern restored by the light intensity signal.

[0031] Optionally, each of the stripe patterns is composed of a pixel array, each row of pixels is divided into a stripe, or each column of pixels is divided into a stripe, the grayscale values ​​of pixels belonging to the same stripe are the same, and along the direction of stripe arrangement, the grayscale values ​​of all stripes constituting the pixel array are sinusoidally or cosine distributed.

[0032] Optionally, the stripe patterns emitted by the light source of the mobile phone are in two groups, each group of stripe patterns is four, the stripes in the four stripe patterns in each group are arranged in the same direction, and the stripe pattern belonging to the latter one in each group of stripe patterns is formed by moving the previous stripe pattern by π / 2 along the arrangement direction of the stripe group; among the two groups of stripe patterns, the four stripe patterns in the second group are formed by rotating the four stripe patterns in the first group by 90 degrees one by one.

[0033] Optionally, calculating the real phase of the component to be tested based on the real light intensity signal includes: calculating the horizontal phase of the component to be tested based on one of the two groups of light intensity signals, and calculating the vertical phase of the component to be tested based on the other group of the two groups of light intensity signals; the number of stripe patterns emitted by the mobile phone light source is the same as the number of light intensity signals, and corresponds one to one.

[0034] Further optionally, the ideal phase includes the horizontal phase and the vertical phase of the ideal stripe pattern; and obtaining the phase difference of the component to be tested based on the real phase of the component to be tested and the ideal phase includes: obtaining the phase difference of the component to be tested based on the horizontal phase of the component to be tested, the vertical phase of the component to be tested, the horizontal phase of the ideal stripe pattern and the vertical phase of the ideal stripe pattern.

[0035] (III) Beneficial effects

[0036] (1) An aberration detection device based on a mobile phone light source provided in an embodiment of the present invention does not need to use a traditional large-aperture wavefront detector and interferometer, but uses a mobile phone that is more easily available in life as a light source, thereby reducing the requirements for the surface accuracy of the illumination light source. In addition, the device has a simple structure and is easy to use. It does not require precise and strict optical path adjustment of the components to be tested, thereby reducing the complexity of the device and the difficulty of optical path adjustment.

[0037] (2) The aberration detection device based on the mobile phone light source provided in the embodiment of the present invention can be provided with one or more optical components in the light expansion projection system of the device. The multiple optical components are arranged in sequence on the same optical axis. The fringe pattern emitted by the mobile phone light source of a smaller size can be spatially enlarged to illuminate and detect the aberration of the component to be tested with a larger aperture, thereby enhancing flexibility and practicality.

[0038] (3) The mobile phone light source detection device provided in the embodiment of the present invention utilizes the mobile phone light source to project 8 stripe patterns to illuminate the components to be tested. The stripe patterns occupy a small amount of data memory and can more efficiently and conveniently detect the aberration of the components to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 This is a structural schematic diagram of an aberration detection device based on a mobile phone light source according to Embodiment 1 of the present invention;

[0041] Figure 2 This is a structural schematic diagram of an aberration detection device based on a mobile phone light source according to a second embodiment of the present invention;

[0042] Figure 3 A schematic diagram of a stripe pattern emitted by a light source of a mobile phone in the device provided in Example 1;

[0043] Figure 4 for Figure 3 The fringe pattern shown is a schematic diagram of a fringe pattern restored by a reflected light intensity signal collected by an optical camera after the fringe pattern is reflected by a component to be tested;

[0044] Figure 5 The discrete phase distribution generated in the x and y directions of the first embodiment;

[0045] Figure 6 Generating a continuous phase distribution after phase unwrapping for the x and y directions of the first embodiment;

[0046] Figure 7 The slope distribution generated in the x and y directions of Example 1;

[0047] Figure 8 This is the wavefront aberration distribution of the component to be tested after restoration in Example 1.

[0048] Fig. 9 This is the wavefront aberration distribution of the component to be tested after restoration in Example 2.

[0049] In the figure:

[0050] 1: Mobile phone light source; 2: Optical beam expansion projection system; 3: Components to be tested; 4: Optical camera. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0052] Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0054] The first embodiment of the present invention provides an aberration detection device based on a mobile phone light source, the device comprising: a mobile phone light source 1, an optical beam expansion projection system 2 and an optical camera 4; the mobile phone light source 1 is used to project a stripe pattern onto the optical beam expansion projection system 2; the optical beam expansion projection system 2 is used to expand the spatial size of the stripe pattern projected by the mobile phone light source 1 according to a preset multiple, and project the expanded stripe pattern onto the surface of a component 3 to be tested; the optical camera 4 is used to collect the light intensity signal reflected or transmitted by the component 3 to be tested from the stripe pattern projected onto its own surface.

[0055] In some embodiments, the above-mentioned device also includes: a calculation module, which is used to obtain the phase difference of the component to be tested based on the real phase of the component to be tested corresponding to the light intensity signal and the ideal phase corresponding to the ideal fringe pattern, and calculate the aberration of the component to be tested based on the phase difference; the ideal fringe pattern is generated based on the fringe pattern emitted by the mobile phone light source and the three-dimensional information of the component to be tested.

[0056] Figure 3 This is a schematic diagram of a stripe pattern emitted by a light source of a mobile phone in the device provided in Example 1.

[0057] like Figure 3 As shown in the left and right figures of the , the two figures respectively represent two stripe patterns. The stripes in the left figure are vertical stripes, and multiple vertical stripes are distributed along the horizontal direction (horizontal direction, or called x direction). The stripes in the right figure are horizontal stripes, and multiple horizontal stripes are distributed along the longitudinal direction (vertical direction, or called y direction).

[0058] Each of the stripe patterns is composed of a pixel array, each row of pixels is divided into a stripe group, or each column of pixels is divided into a stripe group, the grayscale values ​​of pixels belonging to the same stripe group are the same, and along the direction of arrangement of the stripe groups, the grayscale values ​​of all the stripe groups constituting the pixel array are sinusoidally or cosinely distributed.

[0059] from Figure 3 As can be seen from the left picture, each column of pixels is a stripe group, and the stripe groups are arranged horizontally, that is, from left to right, each column of pixels gradually deepens from gray, then turns black, then gradually lightens to form white, and then turns black, and so on to the far right of the left picture. Figure 3 The left figure shows that the grayscale values ​​of the pixels of each stripe group in each column are different. That is, along the direction in which the stripe groups are arranged, the grayscale values ​​of all the stripe groups constituting the pixel array are distributed in a sine or cosine manner.

[0060] Figure 3 The stripe pattern on the right is made of Figure 3 The left picture is obtained by rotating 90 degrees and will not be repeated here.

[0061] In the device provided in Example 1, the mobile phone light source 1 is used to project two groups of stripe patterns to the optical beam expansion projection system in sequence; the number of the stripe patterns in each group is 4, the arrangement direction of the stripes in the 4 stripe patterns in each group is the same, and the stripe pattern belonging to the latter in each group of stripe patterns is formed by moving the previous stripe pattern by π / 2 along the arrangement direction of the stripe group; in the 2 groups of stripe patterns, the 4 stripe patterns in the second group are formed by rotating the 4 stripe patterns in the first group by 90 degrees one by one.

[0062] In some embodiments, the above-mentioned device also includes an ideal fringe pattern generating unit, which is used to generate the fringe pattern based on the fringe pattern emitted by the mobile phone light source and the three-dimensional information of the component to be tested.

[0063] The ideal stripe pattern generating unit is used to pre-generate two groups of stripe patterns and transmit the generated two groups of stripe patterns to the mobile phone light source 1.

[0064] Optionally, the color of the stripes can be any color, such as black, white or color.

[0065] Optionally, the laser intensity distribution of each generated fringe pattern can be parameterized according to a specific experimental device, and the specific light intensity distribution is described by the following formula (sinusoidal fringe):

[0066] I=a+bcos(2πr / p+t)

[0067] Where: a represents the background light intensity, b represents the amplitude, 2πr / p represents the phase, r represents the position coordinate of the pixel point on the fringe pattern, p is the period of the sinusoidal fringe, and t represents the phase shift.

[0068] Furthermore, the total number of fringe patterns of each group projected by the mobile phone light source 1 to the optical beam expansion system 2 is N, and N=4, then the relationship between N and the phase shift t satisfies:

[0069]

[0070] Here, n represents the number of the stripe pattern in the group of stripe patterns that is currently emitted, that is, n is less than or equal to N. In this embodiment, N is 4.

[0071] In some embodiments, a calculation module is used to obtain the phase difference of the component under test according to the real phase corresponding to the light intensity signal and the ideal phase corresponding to the ideal fringe pattern, including: a calculation module, used to calculate the real phase of the component under test according to the light intensity signal collected by the optical camera, the light intensity signal is formed by the reflection or transmission of the expanded fringe image by the component under test, and the expanded fringe image is formed by the optical expansion projection system expanding the fringe pattern emitted by the mobile phone light source; calculating the ideal phase, the ideal fringe pattern is generated according to the fringe pattern emitted by the mobile phone light source and the three-dimensional information of the component under test; obtaining the phase difference of the component under test according to the real phase of the component under test and the ideal phase; obtaining the aberration of the component under test according to the phase difference.

[0072] A calculation module, used to calculate the real phase of the component to be tested according to the light intensity signal collected by the optical camera, including: the calculation module is used to calculate the phase of the component to be tested according to the two groups of light intensity signals collected by the optical camera, that is, each group of four light intensity signals can generate a phase in one of the horizontal or vertical directions of the component to be tested, that is, one of the two groups of light intensity signals is used to generate the phase of the component to be tested in the horizontal direction, and the other group is used to generate the phase of the component to be tested in the vertical direction. In other words, the two groups of light intensity signals correspond to the light intensity signal of the component to be tested in the horizontal direction of the stripe pattern and the light intensity signal of the component to be tested in the vertical direction of the stripe pattern.

[0073] It can be understood that each of the two groups of light intensity signals is formed by the components to be tested reflecting or transmitting the two groups of expanded fringe images in turn, and the two groups of expanded fringe images are formed by the optical expansion projection system expanding the two groups of fringe patterns emitted by the mobile phone light source in turn according to preset multiples, that is, the number of fringe patterns emitted by the mobile phone light source is the same as the number of light intensity signals, and corresponds one to one; among the two groups of fringe patterns emitted by the mobile phone light source, the number of fringe patterns in each group is 4, the arrangement direction of the 4 fringe patterns in each group is the same, and the latter fringe pattern in each group of fringe patterns is formed by moving the previous fringe pattern by π / 2 along the arrangement direction of the fringe group; among the two groups of fringe patterns, the 4 fringe patterns in the second group are formed by rotating the 4 fringe patterns in the first group by 90 degrees in a one-to-one correspondence.

[0074] More specifically, the calculation module is used to calculate the real phase of the component to be tested according to the light intensity signal, including:

[0075] Firstly, the four-step phase shift method is used to solve the horizontal phase and vertical phase of the component under test corresponding to each group of four light intensity signals.

[0076] Specifically, the phase calculation formula in the horizontal direction (x) and the phase calculation formula in the vertical direction (y) are as follows:

[0077]

[0078] The phase calculation formula in the vertical direction is as follows:

[0079]

[0080] I′ 1x ~I′ 4x and I′ 1y ~I′ 4y They are the light intensity in the x and y directions of the non-ideal fringe pattern (real fringe pattern) when the mobile phone light source projects each fringe pattern in the x and y directions in turn, irradiates the component 3 to be tested after being expanded by the beam expansion projection system, and restores the light intensity signal collected by the optical camera after being reflected or transmitted by the component 3 to the light intensity signal collected by the optical camera.

[0081] Furthermore, the two phases of the component under test calculated by the phase calculation formula in the x and y directions and the phase of the component under test on the non-ideal fringe pattern satisfy the relationship:

[0082]

[0083]

[0084] Δx and Δy are the fringe offsets in the x and y directions of the fringe pattern restored by the optical camera due to the phase difference information at each test point on the test component, and x′ and y′ are the one-dimensional coordinates of the non-ideal fringes along the arrangement direction.

[0085] It can be understood that in this embodiment, in the two groups of fringe patterns (each group of fringe patterns includes four fringe patterns) projected by the mobile phone light source 1 respectively, each fringe pattern is considered to have no aberration before being projected onto the component to be tested, and can be called an ideal fringe pattern (see Figure 3 The fringe pattern restored from the light intensity signal collected by the optical camera after reflection or transmission from the component to be tested may have aberrations. The fringe pattern restored from the light intensity signal can be called a non-ideal fringe pattern (see Figure 4 left and right images of ).

[0086] Figure 4 The left picture is Figure 3 The left figure is a fringe pattern restored by the light intensity signal collected by the optical camera 4 after being reflected by the component to be tested. The fringe pattern has aberration and is a non-ideal fringe pattern. Figure 4 The right picture is Figure 3 The fringe pattern restored from the light intensity signal collected by the optical camera 4 after being reflected by the component to be tested in the right figure is a non-ideal fringe pattern.

[0087] In some embodiments, before calculating the phase of the component to be tested according to the light intensity signal collected by the optical camera, the calculation unit may first calculate the ideal phase corresponding to the ideal fringe pattern, or the calculation unit may receive the phase of the fringe pattern calculated by the host computer, that is, the ideal phase corresponding to the ideal fringe pattern. The phase of the fringe pattern includes two phases of the fringe pattern in the horizontal direction (x direction) and the vertical direction (y direction) of the fringe pattern.

[0088] Specifically, the ideal phases of the ideal fringe patterns in the x and y directions are calculated using the following phase calculation formulas:

[0089]

[0090]

[0091] I 1x ~I 4x and I 1y ~I 4y are the light intensities of each ideal fringe pattern projected in sequence by the mobile phone light source in the x direction and the y direction respectively when the mobile phone light source projects each ideal fringe pattern in sequence in the x direction and the y direction respectively.

[0092] The phase calculated by the phase calculation formula in the x and y directions satisfies the relationship with the actual phase of the fringe pattern:

[0093]

[0094]

[0095] In the above formula, x and y are the one-dimensional coordinates of the stripe pattern along the arrangement direction.

[0096] In some embodiments, a calculation unit is used to obtain the phase difference of the component under test based on the real phase corresponding to the light intensity signal and the phase corresponding to the ideal fringe pattern, including: a calculation unit is used to obtain the phase difference of the component under test based on the horizontal phase and vertical phase of the component under test corresponding to the real light intensity signal, and the horizontal (x) phase and vertical (y) phase of the ideal fringe pattern.

[0097] Furthermore, the phase difference of the component under test in the x and y directions can be solved by the following formulas respectively:

[0098]

[0099]

[0100] In some embodiments, the calculation unit is further used to obtain a continuous phase difference at the component under test 3 through a phase unwrapping technique after obtaining the phase difference of the component under test according to the real phase corresponding to the light intensity signal and the ideal phase corresponding to the ideal fringe pattern.

[0101] In some embodiments, obtaining the aberration of the component to be tested according to the phase difference includes: first, obtaining the offset of the same pixel point in the real fringe pattern restored by the real light intensity signal and the ideal fringe pattern according to the phase difference.

[0102] Specifically, the above formula The calculated offset of each pixel.

[0103] Secondly, the slope of the pixel point corresponding to the offset relative to the transmission direction of the light incident on the pixel point is calculated according to the offset.

[0104] The specific formula for calculating the slope of a pixel is as follows:

[0105]

[0106]

[0107] Where: x m and m is the position coordinate of any point on the component under test, x camera and camera is the coordinate of the corresponding point recorded on the optical camera, x screen and screen are the coordinates of the corresponding points on the fringe pattern after the fringe pattern of the mobile phone light source is expanded by the optical beam expansion projection system, and z1 and z2 are the distances from the fringe pattern after the fringe pattern of the mobile phone light source is expanded by the optical beam expansion projection system to the component under test 3 and from the component under test 3 to the optical camera 4 along the z-axis direction of the optical axis.

[0108] Finally, the deformation amount of the device under test at the position corresponding to the pixel point is calculated according to the slope at each pixel point; the aberration of the device under test is composed of the deformation amounts of all the pixels of the fringe pattern restored by the light intensity signal.

[0109] Specifically, the wavefront aberration on the component 3 to be tested can be restored using the regional method.

[0110] In summary, this embodiment first assumes that the component 3 to be tested is an ideal component without aberration in the surface shape, and assumes that the coordinates of the fringe image on the optical camera are known. The coordinates of the fringe pattern on other devices such as the mobile phone light source 1, the optical beam expansion projection system 2, and the component 3 to be tested should all be represented by the coordinates of the fringe image on the optical camera. The whole process fringe pattern is grid-divided according to the distribution mode of the number of pixels in the imaging area of ​​the fringe pattern on the optical camera, and an ideal fringe pattern with a consistent distribution mode of the number of pixels is pre-generated and pre-loaded on the mobile phone light source 1. Then, the number and distribution mode of the pixels of the primary fringe pattern projected by the mobile phone light source 1 and the secondary fringe pattern after the primary fringe pattern is expanded by the optical beam expansion projection system 2 are consistent. The mapping relationship between the position coordinates of the imaging point on the component 3 to be tested and the optical camera 4 after the light emitted from any point on the mobile phone screen 1 is theoretically calculated. Combined with the mapping relationship at this time, the relationship between the position coordinates of the imaging point when the component 3 to be tested has a small aberration is calculated, so as to solve the slope on the component 3 to be tested.

[0111] Finally, the wavefront aberration distribution on the component 3 to be tested can be restored by using the slope in combination with the regional wavefront restoration method.

[0112] In this embodiment, the wavefront aberration is directly restored by using the slope information through the regional wavefront restoration method, so that the wavefront aberration can be detected quickly.

[0113] The device of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0114] Embodiment 1

[0115] Figure 1 The structure diagram of an aberration detection device based on a mobile phone light source provided in the first embodiment of the present invention. The device includes a mobile phone light source 1, an optical beam expansion projection system 2, and an optical camera 4. Figure 1 In the illustrated embodiment, the surface of the component to be tested reflects the stripe pattern illuminated by the optical beam expansion projection system 2 .

[0116] Figure 1In the embodiment shown, the experimental device selects the mobile phone screen as the small display screen in the optical system. The mobile phone model is iPhone 8, the screen is a liquid crystal display LCD, the screen size is 4.7 inches, and the pixel resolution is 1334px×750px, so the diagonal length of the physical size of the screen is about 119.38mm, and the length and width are about 105mm and 60mm respectively. The stripe pattern projected from the mobile phone LCD screen passes through an optical beam expansion projection system with a magnification of 4 times. The optical beam expansion projection system uses an optical magnification system composed of two optical lenses. The first lens is a concave lens with a curvature of -200mm, and the second lens is a plano-convex lens, the convex surface is the light-emitting surface, and the curvature is 3200mm. The two lenses are 350mm apart. After the fringe pattern is magnified by the optical beam expansion projection system, the size of the fringe pattern generated at a distance of 140mm from the convex lens is about 420mm long and 240mm wide; the imaging target size of the pinhole CCD camera receiving the image is 12.44mm long and 9.83mm wide, and it is assumed that the CCD camera is located 10mm above the secondary projection screen. The CCD camera model is acA2500-60um, the number of bits is 10bits, the resolution is 2592px×2048px, and the size of each pixel is 4.8μm×4.8μm. The effective light transmission target size of the camera is 1″, that is, 12.4mm×9.8mm; the component to be tested is a rectangular reflective structure of 150mm×75mm, and the distances from the secondary projection fringe pattern to the component to be tested and from the component to the optical camera are z1=200mm and z2=99.5mm respectively.

[0117] For the convenience of calculation, the spatial distance units of the whole text are unified into millimeters (mm). Assume that the grid is divided into 1000×1000. The parameters set in the simulation are as follows: Set the fringe period on the CCD camera to 50 pixels, then the physical size of the fringe period is about 0.622mm. According to the four-step phase shift method (N=4), the fringe patterns projected by the LCD display in the x and y directions are generated by simulation. Taking the x direction as an example, after generating 4 ideal fringe images respectively, the corresponding ideal fringe light intensity at this time and the light intensity of the non-ideal fringe with small wavefront distortion after passing through the mirror to be tested should be recorded in the CCD camera, a total of 8 light intensity values ​​I1~I4 and I′1~I′4

[0118] Specifically, after deformation according to I=a+bcos(2πr / p+t), the ideal fringe pattern is obtained:

[0119]

[0120] Where n∈[1,N], is the phase at each point when the ideal fringe pattern is input, that is, the initial phase, x is the grid coordinate of the LCD display in the x direction, and the phase shift

[0121] According to the four-step phase shift method, taking the phase shift t = 0 as an example, the ideal fringe images in the x-direction and y-direction on the LCD display generated at this time after the secondary projection of the optical beam expansion projection system are as follows: Figure 3 As shown:

[0122] After introducing the fringe offset according to I = a + bcos (2πr / p + t) to deform, the non-ideal fringe pattern containing wavefront distortion recorded in the CCD camera is obtained:

[0123]

[0124]

[0125] Where n∈[1,N], is the phase at each point on the non-ideal fringe recorded in the CCD camera, that is, the wavefront phase of the surface to be measured. is the phase, x′ is the grid coordinate of the LCD display in the x direction, and the phase shift t=2π(n-1) / N.

[0126] Adding a fringe offset with a maximum value of 0.48 mm and a regular spatial distribution to the ideal fringe phase will produce a non-ideal fringe pattern with wavefront distortion recorded on the CCD camera, such as Figure 4 As shown. Solving the discrete phase difference in the x and y directions is as follows Figure 5 The discrete phase is unwrapped to obtain the continuous phase, and the phase distribution after phase unwrapping in the x and y directions is obtained, as shown in Figure 6 As shown in FIG. 1 , based on the assumption that the component to be tested is an ideal device, the coordinate mapping relationship between the LCD, CCD camera and the surface shape to be tested is established, and the slope distribution in the x and y directions is obtained.

[0127] like Figure 7 After obtaining the slope distribution in the x and y directions and the phase distribution after phase unwrapping, the wavefront of the mirror to be tested is reconstructed using the Southwell wavefront reconstruction algorithm, as shown in Figure 8As shown, from the results on the image, it is found that the aberration of the mirror to be tested is relatively small, and at this time PV=I.0516μm. When using a computer to encode the stripe pattern, if the resolution of the grid division is doubled, the aberration detection technology based on the mobile phone light source of the present invention can obtain a much better imaging effect than the ordinary current grid resolution, and the detection accuracy is comparable to the traditional aberration detection technology. It can be seen from this embodiment that this embodiment 1 combines theoretical calculations and simulations to achieve aberration detection when the aberration of the component to be tested is relatively small. In addition, compared with the traditional aberration detection device, the detection device provided by the embodiment of the present invention can use a small mobile phone as the light source of the detection device, so that the detection device provided by this embodiment is small in size, integrated, portable, and highly flexible.

[0128] Embodiment 2

[0129] Figure 2 A schematic diagram of the structure of a phase difference detection device based on a mobile phone light source provided in the second embodiment of the present invention. The component 3 to be tested in the device transmits the strip pattern illuminated by the optical beam expansion projection system 2. The experimental device selects the mobile phone screen as the small display screen in the optical system. The mobile phone model is iPhone 8, the screen is a liquid crystal display LCD, the screen size is 4.7 inches, and the pixel resolution is 1334px×750px, so the diagonal length of the physical size of the screen is about 119.38mm, and the length and width are about 105mm and 60mm respectively. The stripe pattern projected from the mobile phone LCD display screen passes through an optical beam expansion projection system with a magnification of 4 times. The optical beam expansion projection system uses an optical magnification system composed of two optical lenses. The first lens is a concave lens with a curvature of -200mm, and the second lens is a plano-convex lens, the convex surface is the light-emitting surface, and the curvature is 3000 mm. The two lenses are 300mm apart. After the fringe pattern is magnified by the optical beam expansion projection system, the size of the fringe pattern generated at a distance of 180mm from the convex lens is about 420mm long and 240mm wide; the imaging target size of the pinhole CCD camera receiving the image is 12.44mm long and 9.83mm wide, and it is assumed that the CCD camera is located 20mm behind the component to be tested. The CCD camera model is acA2500-60um, the number of bits is 10bits, the resolution is 2592px×2048px, and the size of each pixel is 4.8μm×4.8μm. The effective light transmission target size of the camera is 1″, that is, 12.4mm×9.8mm; the component to be tested is a rectangular transmission structure of 150mm×75mm, and the distances from the secondary projection fringe pattern to the component to be tested and from the component to the optical camera are 200mm and 99.5mm respectively.

[0130] For the convenience of calculation, the spatial distance units of the whole text are unified into millimeters (mm). Assume that the grid is divided into 1000×1000. The parameters set in the simulation are as follows: Set the fringe period on the CCD camera to 50 pixels, then the physical size of the fringe period is about 0.622mm. According to the four-step phase shift method (N=4), a fringe offset with a maximum value of 0.1592mm and a certain regular spatial distribution is added to the ideal fringe phase, and the fringe pattern projected by the LCD display in the x and y directions is generated through simulation. Taking the x direction as an example, after generating 4 ideal fringe images respectively, the corresponding ideal fringe light intensity at this time and the light intensity of the non-ideal fringe with small aberrations after passing through the mirror to be tested should be recorded in the CCD camera, a total of 8 light intensity values ​​I1~I4 and As shown in FIG9 , it is found from the results on the image that the wavefront distortion of the mirror to be tested is relatively small, and at this time PV=I.0093 μm. It can be seen that the aberration results obtained by restoring the components to be tested with a reflective or projecting structure using this method are basically the same.

[0131] The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that various combinations, modifications or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and should be included in the scope of the claims of the present invention.

Claims

1. An aberration detection device based on a mobile phone light source, characterized in that: include: Mobile phone light source (1), optical beam expansion projection system (2) and optical camera (4); The mobile phone light source (1) is used to project a fringe pattern onto the optical beam expansion projection system (2); The optical beam expansion projection system (2) is used to expand the spatial dimensions of the fringe pattern projected by the mobile phone light source (1) according to a preset multiple, and project the expanded fringe pattern onto the surface of the component to be tested (3); The optical camera (4) is used to collect light intensity signals after the component (3) to be tested reflects or transmits the stripe pattern projected onto its own surface.

2. The device according to claim 1, characterized in that Also includes: A calculation module, the calculation module is used to obtain a phase difference of the component to be tested according to a real phase of the component to be tested corresponding to the light intensity signal and an ideal phase corresponding to the ideal fringe pattern, and calculate the aberration of the component to be tested according to the phase difference; The ideal fringe pattern is generated based on the fringe pattern emitted by the mobile phone light source and the three-dimensional information of the components to be tested.

3. The device according to claim 2, characterized in that Each of the stripe patterns is composed of a pixel array, each row of pixels is divided into a stripe, or each column of pixels is divided into a stripe, the grayscale values ​​of pixels belonging to the same stripe are the same, and along the direction of stripe arrangement, the grayscale values ​​of all stripes constituting the pixel array are sinusoidally or cosine distributed.

4. The device according to claim 3, characterized in that The mobile phone light source (1) is used to project two groups of stripe patterns respectively and in sequence to the optical beam expansion projection system; the number of the stripe patterns in each group is four, the stripes in the four stripe patterns in each group are arranged in the same direction, and the stripe pattern belonging to the latter in each group of stripe patterns is formed by moving the previous stripe pattern by π / 2 along the stripe group arrangement direction; In the two groups of stripe patterns, the four stripe patterns in the second group are formed by rotating the four stripe patterns in the first group by 90 degrees in a one-to-one correspondence.

5. The device according to any one of claims 1 to 4, characterized in that: The optical beam expansion projection system (2) is a single optical component, and the single optical component is arranged on the same optical axis as the mobile phone light source (1); or, The optical beam expansion projection system (2) comprises a plurality of optical components, and the plurality of optical components are arranged on a common optical axis.

6. The device according to any one of claims 1 to 4, characterized in that: The mobile phone light source (1) is one of the current thin film field effect transistor screen, in-plane switching screen, liquid crystal display screen or organic light emitting diode screen.

7. The device according to any one of claims 1 to 4, characterized in that: The surface of the component to be tested (3) can transmit or reflect the stripe pattern.

8. A mobile phone-based aberration detection method based on the device according to any one of claims 1 to 7, characterized in that: include: Calculate the real phase of the component under test according to the light intensity signal, wherein the light intensity signal is collected after the component under test reflects or transmits the expanded fringe pattern, and the expanded fringe pattern is formed by expanding the fringe pattern emitted by the mobile phone light source according to a preset multiple; calculating an ideal phase, wherein the ideal phase is a phase of an ideal fringe pattern; The ideal fringe pattern is generated based on the fringe pattern emitted by the mobile phone light source and the three-dimensional information of the components to be tested; Obtaining a phase difference of the component under test according to the real phase of the component under test and the ideal phase; The aberration of the component to be tested is obtained according to the phase difference.

9. The method according to claim 8, characterized in that Obtaining the aberration of the component to be tested according to the phase difference includes: Obtaining, according to the phase difference, an offset between a real fringe pattern restored by the light intensity signal and a same pixel point in the ideal fringe pattern; Calculating, according to the offset, a slope of a pixel point corresponding to the offset relative to a transmission direction of light incident on the pixel point; The deformation amount of the device under test at the position corresponding to the pixel point is calculated according to the slope at each pixel point; the aberration of the device under test is composed of the deformation amounts of all the pixel points of the fringe pattern restored by the light intensity signal.

10. The method according to claim 8 or 9, characterized in that: Each of the stripe patterns is composed of a pixel array, each row of pixels is divided into a stripe, or each column of pixels is divided into a stripe, the grayscale values ​​of pixels belonging to the same stripe are the same, and along the direction of arrangement of the stripes, the grayscale values ​​of all the stripes constituting the pixel array are sinusoidally or cosine distributed; the stripe patterns emitted by the mobile phone light source are 2 groups, the number of the stripe patterns in each group is 4, the arrangement direction of the stripes in the 4 stripe patterns in each group is the same, and the stripe pattern belonging to the latter in each group of the stripe patterns is formed by moving the previous stripe pattern by π / 2 along the arrangement direction of the stripe group; in the 2 groups of stripe patterns, the 4 stripe patterns in the second group are formed by rotating the 4 stripe patterns in the first group by 90 degrees one by one.

Images