Liquid crystal cell thickness detection method and system based on coherence tomography technology and medium

Abstract

The invention provides a liquid crystal cell thickness detection method, device, equipment and medium based on coherence tomography, and the method comprises the following steps: generating an incident light beam by using a wide-spectrum low-coherence light source, and dividing the incident light beam into reference light and sample light of which the propagation directions are perpendicular to each other by using a beam splitter; the reference light is reflected back to the beam splitter after being vertically incident to the reflective mirror, and is propagated to an acquisition end along an original propagation direction; enabling the sample light to vertically enter the to-be-detected silicon-based liquid crystal device, then reflecting the sample light back to the beam splitter, changing the direction through the beam splitter, and propagating the sample light to an acquisition end; the interference signals of the reference light and the sample light are collected at the collection end, and the depth information of the to-be-measured silicon-based liquid crystal device is obtained after FFT processing is carried out on the interference signals, so that the problem that the thickness of a small-size liquid crystal box is difficult to accurately measure is solved.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal cell thickness detection technology, and in particular to a method, apparatus, equipment and medium for liquid crystal cell thickness detection based on coherence tomography technology. Background Technology

[0002] Liquid crystal on silicon (LCoS) technology, a display technology that integrates liquid crystal materials and complementary metal-oxide-semiconductor (CMOS) technology, has attracted much attention in many fields due to its unique performance. Among them, pure phase-type LCoS devices play an indispensable role in many fields such as optical communication, laser processing, biomedicine, and scientific research because of their excellent flexibility and high efficiency in spatial light field manipulation. However, the fabrication of these pure phase-type LCoS devices requires extremely high levels of technological expertise, necessitating precise control of various structural parameters to ensure that their performance meets expected standards.

[0003] Current liquid crystal devices (LCDs) generally employ a sandwich structure, typically consisting of two cover plates on either side and a liquid crystal layer in the middle. The thickness of this liquid crystal layer is defined as the cell thickness of the LCD device. Deviations in cell thickness can severely negatively impact the optical performance of the device, thereby affecting its normal operation. In practical designs, the cell thickness is usually determined based on the maximum modulation phase depth of the silicon-based liquid crystal device. Cell thicknesses obtained using this design approach are often very small, typically only 1–2 μm. Such a small cell thickness makes accurate measurement extremely difficult, and this measurement challenge has become one of the bottlenecks restricting the further development and application of pure phase-based silicon-based liquid crystal devices.

[0004] Therefore, there is an urgent need to propose a liquid crystal cell thickness detection method based on coherence tomography technology to solve the technical problem of accurately measuring the thickness of small-sized liquid crystal cells. Summary of the Invention

[0005] To overcome the problems existing in related technologies, this disclosure provides a liquid crystal cell thickness detection method, apparatus, device and medium based on coherence tomography technology, so as to solve the technical problem that it is difficult to accurately measure the thickness of small-sized liquid crystal cells in related technologies.

[0006] This specification provides one or more embodiments of a liquid crystal cell thickness detection method based on coherent tomography technology, including the following steps:

[0007] An incident beam is generated using a broadband low-coherence light source, and a beam splitter is used to split the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions.

[0008] The reference light is incident perpendicularly on the reflector and reflected back to the beam splitter, then propagates along the original propagation direction to the acquisition end;

[0009] The sample light is incident perpendicularly onto the silicon-based liquid crystal device under test, then reflected back to the beam splitter, and the beam splitter changes its direction to propagate to the acquisition end.

[0010] The interference signal of the reference light and the sample light is acquired at the acquisition end. After performing FFT processing on the interference signal, the depth information of the silicon-based liquid crystal device under test is obtained.

[0011] Preferably, the acquisition end acquires the interference signal between the reference light and the sample light, specifically including the following steps:

[0012] The acquisition end includes a grating and a CCD camera;

[0013] The interference signal is obtained by dispersing the reference light and the sample light through the grating;

[0014] The interference signal is received by the CCD camera.

[0015] Preferably, obtaining the depth information of the silicon-based liquid crystal device under test after performing FFT processing on the interference signal specifically includes the following steps:

[0016] The interference signal is processed by FFT to obtain information on the relative reflectivity of different surfaces of the silicon-based liquid crystal device under test as a function of depth.

[0017] By finding different depths corresponding to different interfaces through different peak values ​​of relative reflectivity, the thickness of the liquid crystal cell can be calculated.

[0018] Preferably, the FFT processing of the interference signal further includes the following steps:

[0019] Before performing FFT processing, the interference signal is subjected to background denoising and normalization.

[0020] This specification provides one or more embodiments of a liquid crystal cell thickness detection device based on coherence tomography technology, including a beam generation module, a reference light module, a sample light module, and a detection module;

[0021] The beam generation module is used to generate an incident beam using a broadband low-coherence light source, and to split the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions using a beam splitter.

[0022] The reference light module is used to make the reference light perpendicularly incident on the reflector and reflected back to the beam splitter, and then propagate to the acquisition end along the original propagation direction;

[0023] The sample optical module is used to make the sample light perpendicularly incident on the silicon-based liquid crystal device under test, reflect it back to the beam splitter, and then change its direction through the beam splitter to propagate to the acquisition end.

[0024] The detection module is used to acquire the interference signal of the reference light and the sample light at the acquisition end, and to obtain the depth information of the silicon-based liquid crystal device under test after performing FFT processing on the interference signal.

[0025] Preferably, the detection module includes a data acquisition unit, and the data acquisition end includes a grating and a CCD camera. The data acquisition unit is configured as follows:

[0026] The interference signal is obtained by dispersing the reference light and the sample light through the grating;

[0027] The interference signal is received by the CCD camera.

[0028] Preferably, the detection module further includes an FFT processing unit, the FFT processing unit being configured as follows:

[0029] The interference signal is processed by FFT to obtain information on the relative reflectivity of different surfaces of the silicon-based liquid crystal device under test as a function of depth.

[0030] By finding different depths corresponding to different interfaces through different peak values ​​of relative reflectivity, the thickness of the liquid crystal cell can be calculated.

[0031] Preferably, the detection module further includes a preprocessing unit, the preprocessing unit being configured as follows:

[0032] Before performing FFT processing, the interference signal is subjected to background denoising and normalization.

[0033] This specification provides one or more embodiments of a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the liquid crystal cell thickness detection method based on coherence tomography technology as described above.

[0034] This specification provides one or more embodiments of a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the liquid crystal cell thickness detection method based on coherence tomography technology described above.

[0035] This disclosure provides a method, apparatus, device, and medium for detecting the thickness of a liquid crystal cell based on coherent tomography (CTT). The advantages are: by using a broadband low-coherence light source to generate the incident beam, interference from incoherent light is significantly reduced, ensuring high contrast and signal-to-noise ratio in the subsequent interference signal; a beam splitter divides the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions, providing independent and well-defined propagation paths for each beam, laying the foundation for subsequent interference detection and ensuring spatial separation and independent propagation of the two beams, facilitating subsequent control and processing; the reference beam is perpendicularly incident on the reflector and reflected back to the beam splitter, minimizing optical path offset and energy loss during reflection, ensuring the propagation stability and intensity consistency of the reference beam, and propagating along the original propagation direction to the acquisition end, guaranteeing the stability of the reference beam in propagation path length and phase, providing a reliable reference for forming a stable interference signal with the sample beam; and the sample beam is perpendicularly incident on the silicon-based liquid crystal device under test. The beam splitter reflects the light back to the sample light, avoiding path distortion and information loss caused by incident angle deviation. This ensures that the sample light accurately reflects the internal structural information of the device, especially the depth information related to the liquid crystal cell thickness. The beam splitter changes the direction of the light before it propagates to the acquisition end, achieving convergence of the sample light and reference light at the acquisition end. This creates conditions for interference between the two, and the direction change process is stable, ensuring the integrity of the sample light signal. The interference signal of the reference light and sample light is acquired at the acquisition end, capturing the interference phenomenon caused by the optical path difference between the reference light and the sample light. The interference signal contains depth-related information of the device under test. After performing FFT processing on the interference signal, the depth information of the silicon-based liquid crystal device under test is obtained. The interference signal can be converted from the time domain to the frequency domain, thereby accurately extracting the depth information corresponding to the liquid crystal cell thickness. This enables precise measurement of minute cell thicknesses, solving the problem that traditional methods cannot accurately detect small cell thicknesses. It provides reliable data support for the quality control and performance optimization of silicon-based liquid crystal devices. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A schematic flowchart illustrating a liquid crystal cell thickness detection method based on coherence tomography technology provided in one or more embodiments of this specification;

[0038] Figure 2 A schematic diagram of a liquid crystal cell thickness detection device provided in one or more embodiments of this specification.

[0039] Figure 3 Effective interference signal I received by the CCD camera provided in one or more embodiments of this specification c (K) Schematic diagram of the normalized intensity as a function of the normalized wavenumber k / K0;

[0040] Figure 4 A schematic diagram illustrating the variation of relative reflectance of a sample with depth for one or more embodiments provided in this specification;

[0041] Figure 5 A schematic diagram of a liquid crystal cell thickness detection device based on coherence tomography technology provided for one or more embodiments of this specification;

[0042] Figure 6 This is a schematic diagram of the structure of a computer device provided for one or more embodiments of this specification. Detailed Implementation

[0043] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this invention.

[0044] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0045] Method Implementation Examples

[0046] According to embodiments of the present invention, a method for detecting the thickness of a liquid crystal cell based on coherent tomography is provided, such as... Figure 1 The diagram shown is a flowchart illustrating the liquid crystal cell thickness detection method based on coherent tomography technology provided in this embodiment. The liquid crystal cell thickness detection method based on coherent tomography technology according to this embodiment includes the following steps:

[0047] S110. An incident beam is generated using a broadband low-coherence light source. A beam splitter splits the incident beam into beams with mutually perpendicular propagation directions. The light incident on the reflecting mirror is called the reference light, and the light incident on the silicon-based liquid crystal device under test is called the sample light. The broadband light source, beam splitter, reflecting mirror, and silicon-based liquid crystal device under test constitute a classic Michelson interferometer system. The light source is a broadband low-coherence light source, typically a superluminescent diode, such as... Figure 2 The diagram shown is a schematic of the liquid crystal cell thickness detection device provided in this embodiment.

[0048] S120: The reference light is incident perpendicularly on the reflector and reflected back to the beam splitter along the original path, and then propagates to the acquisition end along the original propagation direction.

[0049] S130: The sample light is incident perpendicularly onto the silicon-based liquid crystal device under test and then reflected back to the beam splitter along the original path. The beam splitter changes the direction of the light and propagates it to the acquisition end.

[0050] The electric field intensity of the reference light and the sample light can be expressed by the following formula:

[0051]

[0052] Among them, E R E(W) and Es(W) represent the electric field intensity of the reference light and the sample at frequency W, respectively, and E0(W) represents the electric field intensity of the incident light at frequency W. R l s r represents the depth of the mirror and the depth of the sample, respectively. R r s (l s ) represent the reflectivity of the mirror and the reflectivity of the sample in l, respectively. s Reflectivity at k R k s This represents the wavenumbers of the reference light and the sample light at frequency W. n R n s The effective refractive index represents the reference and sample directions, k represents the wave number, and c represents the speed of light.

[0053] S140. The reference light and the sample light interfere at the acquisition end. The interference signal of the reference light and the sample light is acquired. After performing FFT processing on the interference signal, the depth information of the silicon-based liquid crystal device under test is obtained.

[0054] The relationship between interference signal intensity and wavenumber is expressed by the following formula:

[0055]

[0056] S(k) is the power spectral density of the Gaussian light source. R 2 To increase the intensity of light reflected by the mirror, extinction at the sample end can be achieved. s =0 was measured;

[0057] To superimpose the reflection signals from different layers of the sample, r can be made more luminous by extinction at the reference end. R =0 was measured;

[0058] To effectively interfere with information, I c(k) After normalization, its relationship with k / k0 is illustrated in the following diagram. Figure 3 As shown (k0 is the wavenumber corresponding to the center wavelength).

[0059] valid signal I c (k) Perform FFT processing to obtain the depth information of the silicon-based liquid crystal device under test.

[0060] The method provided in this embodiment, by using a broadband low-coherence light source to generate the incident beam, can significantly reduce the interference of incoherent light, ensuring that the subsequent interference signal has high contrast and signal-to-noise ratio. A beam splitter is used to split the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions, providing independent and well-defined propagation paths for the reference and sample beams respectively, laying the foundation for subsequent interferometric detection. This ensures the spatial separation and independent propagation of the two beams, facilitating subsequent separate control and processing. The reference beam is incident perpendicularly to the reflector and then reflected back to the beam splitter, minimizing optical path offset and energy loss during reflection, ensuring the propagation stability and intensity consistency of the reference beam, and propagating along the original propagation direction to the acquisition end, guaranteeing the stability of the reference beam in propagation path length and phase, providing a reliable reference for forming a stable interference signal with the sample beam. The sample beam is incident perpendicularly to the silicon-based liquid crystal device under test and then reflected back to the beam splitter, avoiding interference caused by incident angle deviation. The reflection path distortion and information distortion caused by the difference in optical path allow the sample light to accurately reflect the internal structural information of the device, especially the depth information related to the liquid crystal cell thickness. The sample light is then redirected by a beam splitter and propagated to the acquisition end, achieving the convergence of the sample light and the reference light at the acquisition end. This creates conditions for interference between the two, and the direction change process is stable, ensuring the integrity of the sample light signal. The interference signal of the reference light and the sample light is acquired at the acquisition end, capturing the interference phenomenon caused by the optical path difference between the reference light and the sample light. The interference signal contains depth-related information of the device under test. After performing FFT processing on the interference signal, the depth information of the silicon-based liquid crystal device under test is obtained. The interference signal can be converted from the time domain to the frequency domain, thereby accurately extracting the depth information corresponding to the liquid crystal cell thickness. This enables precise measurement of small cell thicknesses, solving the problem that traditional methods are difficult to accurately detect small cell thicknesses. It provides reliable data support for the quality control and performance optimization of silicon-based liquid crystal devices.

[0061] In one embodiment, the acquisition end acquires the interference signal between the reference light and the sample light, specifically including the following steps:

[0062] The acquisition end includes a grating and a CCD camera, and its configuration is similar to that of a spectrometer.

[0063] An interference signal is obtained by dispersing the reference light and the sample light through the grating, and the interference signal is received by the CCD camera.

[0064] In the method provided in this embodiment, the grating separates light of different wavelengths through dispersion at the acquisition end to form an ordered interference signal, avoiding interference and improving quality and information content; the CCD camera captures the signal with high sensitivity and high resolution and digitizes it, providing high-quality data for subsequent processing and ensuring accurate and reliable cell thickness measurement.

[0065] In one embodiment, obtaining the depth information of the silicon-based liquid crystal device under test after performing FFT processing on the interference signal specifically includes the following steps:

[0066] After background denoising and normalization of the interference signal, FFT processing is performed to obtain information on the relative reflectivity of different surfaces of the silicon-based liquid crystal device under test as a function of depth.

[0067] By identifying different depths corresponding to different interfaces through varying peak values ​​of relative reflectivity, the thickness of the liquid crystal cell can be calculated. Specifically, this can be achieved by analyzing the spectrum of the relationship between signal intensity and sample depth; the thickness of the liquid crystal cell can be calculated using the different depth values ​​corresponding to different signal peaks. Figure 4 The diagram shown is a schematic representation of the change in relative reflectance of the sample with depth in this embodiment.

[0068] The method provided in this embodiment can convert the interference signal from the time domain to the frequency domain by performing FFT processing, and accurately obtain information on the change of relative reflectivity with depth of different surfaces of the silicon-based liquid crystal device under test. By using the different peak values ​​of relative reflectivity, the corresponding depth of different interfaces can be clearly located, and the liquid crystal cell thickness can be quickly obtained by calculation, realizing the accurate measurement of minute cell thickness and providing reliable data for device quality control.

[0069] Device Examples

[0070] According to embodiments of the present invention, a liquid crystal cell thickness detection device based on coherence tomography technology is provided, such as... Figure 5 The diagram shown is a schematic diagram of the liquid crystal cell thickness detection device based on coherent tomography technology provided in this embodiment. The liquid crystal cell thickness detection device based on coherent tomography technology according to this embodiment includes a beam generation module 51, a reference light module 52, a sample light module 53, and a detection module 54.

[0071] The beam generation module 51 is used to generate an incident beam using a broadband low-coherence light source and to split the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions using a beam splitter.

[0072] The reference light module 52 is used to make the reference light perpendicularly incident on the reflector and reflected back to the beam splitter, and then propagate to the acquisition end along the original propagation direction.

[0073] The sample light module 53 is used to make the sample light perpendicularly incident on the silicon-based liquid crystal device under test and then reflected back to the beam splitter, and then the beam splitter changes the direction of the light and propagates it to the acquisition end.

[0074] The detection module 54 is used to acquire the interference signal of the reference light and the sample light at the acquisition end, and to obtain the depth information of the silicon-based liquid crystal device under test after performing FFT processing on the interference signal.

[0075] The apparatus provided in this embodiment uses a broadband low-coherence light source to generate an incident beam through a beam generation module 51, which significantly reduces interference from incoherent light and ensures high contrast and signal-to-noise ratio in the subsequent interference signal. A beam splitter separates the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions, providing independent and well-defined propagation paths for each beam. This lays the foundation for subsequent interferometric detection and ensures the spatial separation and independent propagation of the two beams, facilitating their separate control and processing. The reference beam module 52 reflects the reference beam perpendicularly to the reflector back to the beam splitter, minimizing optical path offset and energy loss during reflection. This ensures the stability and intensity consistency of the reference beam's propagation and ensures its stability in propagation path length and phase, providing a reliable reference for forming a stable interference signal with the sample beam. The sample beam module 53 reflects the sample beam perpendicularly to the silicon-based liquid crystal device under test back to the beam splitter. This avoids path distortion and information loss caused by incident angle deviation, ensuring that the sample light accurately reflects the internal structural information of the device, especially the depth information related to the liquid crystal cell thickness. The sample light is redirected by a beam splitter and propagated to the acquisition end, achieving convergence of the sample light and reference light at the acquisition end, creating conditions for interference. The direction change process is stable, ensuring the integrity of the sample light signal. The detection module 54 acquires the interference signal of the reference light and sample light at the acquisition end, capturing the interference phenomenon caused by the optical path difference. The interference signal contains depth-related information of the device under test. After FFT processing of the interference signal, the depth information of the silicon-based liquid crystal device under test is obtained. This allows the interference signal to be converted from the time domain to the frequency domain, thereby accurately extracting the depth information corresponding to the liquid crystal cell thickness. This enables precise measurement of minute cell thicknesses, solving the problem of difficult accurate detection of small cell thicknesses using traditional methods, and providing reliable data support for the quality control and performance optimization of silicon-based liquid crystal devices.

[0076] In one embodiment, the detection module 54 includes a data acquisition unit, the data acquisition unit includes a grating and a CCD camera, and the data acquisition unit is configured as follows:

[0077] An interference signal is obtained by dispersing the reference light and the sample light through the grating, and the interference signal is received by the CCD camera.

[0078] In the device provided in this embodiment, the grating separates light of different wavelengths through dispersion at the acquisition end to form an ordered interference signal, avoiding interference and improving quality and information content; the CCD camera captures the signal with high sensitivity and high resolution and digitizes it, providing high-quality data for subsequent processing and ensuring accurate and reliable cell thickness measurement.

[0079] In one embodiment, the detection module further includes an FFT processing unit, the FFT processing unit being configured as follows:

[0080] After background denoising and normalization of the interference signal, FFT processing is performed on the interference signal to obtain information on the relative reflectivity of different surfaces of the silicon-based liquid crystal device under test as a function of depth.

[0081] By finding different depths corresponding to different interfaces through different peak values ​​of relative reflectivity, the thickness of the liquid crystal cell can be calculated.

[0082] The device provided in this embodiment can convert the interference signal from the time domain to the frequency domain by performing FFT processing, and accurately obtain information on the change of relative reflectivity with depth of different surfaces of the silicon-based liquid crystal device under test. With the help of different peak values ​​of relative reflectivity, the corresponding depth of different interfaces can be clearly located, and the liquid crystal cell thickness can be quickly obtained by calculation, realizing the accurate measurement of minute cell thickness and providing reliable data for device quality control.

[0083] The embodiments of the present invention are device embodiments corresponding to the above method embodiments. The specific operations of each module processing step can be understood with reference to the description of the method embodiments, and will not be repeated here.

[0084] like Figure 6 As shown, the present invention also provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements the liquid crystal cell thickness detection method based on coherent tomography technology in the above embodiments, or when the computer program is executed by a processor, it implements the liquid crystal cell thickness detection method based on coherent tomography technology in the above embodiments.

[0085] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0086] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and the contents not described in detail in the specification of the present invention are known to those skilled in the art.

Claims

1. A method for detecting the thickness of a liquid crystal cell based on coherent tomography, characterized in that, Includes the following steps: An incident beam is generated using a broadband low-coherence light source, and a beam splitter is used to split the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions. The reference light is incident perpendicularly on the reflector and reflected back to the beam splitter, then propagates along the original propagation direction to the acquisition end; The sample light is incident perpendicularly onto the silicon-based liquid crystal device under test, then reflected back to the beam splitter, and the beam splitter changes its direction to propagate to the acquisition end. The interference signal of the reference light and the sample light is acquired at the acquisition end. After performing FFT processing on the interference signal, the depth information of the silicon-based liquid crystal device under test is obtained.

2. The liquid crystal cell thickness detection method based on coherence tomography as described in claim 1, characterized in that, The acquisition of the interference signal between the reference light and the sample light at the acquisition end specifically includes the following steps: The acquisition end includes a grating and a CCD camera; The interference signal is obtained by dispersing the reference light and the sample light through the grating; The interference signal is received by the CCD camera.

3. The liquid crystal cell thickness detection method based on coherence tomography as described in claim 1, characterized in that, The process of performing FFT processing on the interference signal to obtain the depth information of the silicon-based liquid crystal device under test specifically includes the following steps: The interference signal is processed by FFT to obtain information on the relative reflectivity of different surfaces of the silicon-based liquid crystal device under test as a function of depth. By finding different depths corresponding to different interfaces through different peak values ​​of relative reflectivity, the thickness of the liquid crystal cell can be calculated.

4. The liquid crystal cell thickness detection method based on coherence tomography as described in claim 3, characterized in that, The FFT processing of the interference signal further includes the following steps: Before performing FFT processing, the interference signal is subjected to background denoising and normalization.

5. A liquid crystal cell thickness detection device based on coherent tomography technology, characterized in that, It includes a beam generation module, a reference beam module, a sample beam module, and a detection module; The beam generation module is used to generate an incident beam using a broadband low-coherence light source, and to split the incident beam into a reference beam and a sample beam with mutually perpendicular propagation directions using a beam splitter. The reference light module is used to make the reference light perpendicularly incident on the reflector and reflected back to the beam splitter, and then propagate to the acquisition end along the original propagation direction; The sample optical module is used to make the sample light perpendicularly incident on the silicon-based liquid crystal device under test, reflect it back to the beam splitter, and then change its direction through the beam splitter to propagate to the acquisition end. The detection module is used to acquire the interference signal of the reference light and the sample light at the acquisition end, and to obtain the depth information of the silicon-based liquid crystal device under test after performing FFT processing on the interference signal.

6. The liquid crystal cell thickness detection device based on coherence tomography technology as described in claim 5, characterized in that, The detection module includes a data acquisition unit, and the acquisition end includes a grating and a CCD camera. The data acquisition unit is configured as follows: The interference signal is obtained by dispersing the reference light and the sample light through the grating; The interference signal is received by the CCD camera.

7. The liquid crystal cell thickness detection device based on coherence tomography technology as described in claim 5, characterized in that, The detection module further includes an FFT processing unit, which is configured as follows: The interference signal is processed by FFT to obtain information on the relative reflectivity of different surfaces of the silicon-based liquid crystal device under test as a function of depth. By finding different depths corresponding to different interfaces through different peak values ​​of relative reflectivity, the thickness of the liquid crystal cell can be calculated.

8. The liquid crystal cell thickness detection device based on coherence tomography technology as described in claim 7, characterized in that, The detection module further includes a preprocessing unit, which is configured as follows: Before performing FFT processing, the interference signal is subjected to background denoising and normalization.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the liquid crystal cell thickness detection method based on coherence tomography as described in any one of claims 1 to 4.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the liquid crystal cell thickness detection method based on coherence tomography as described in any one of claims 1 to 4.

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