Wave plate adjusting and measuring method and measuring device

Abstract

The invention provides a wave plate adjusting method, which comprises the following steps of: irradiating incident light to a cube-corner prism to obtain reference reflected light; converging the reference reflected light to a light spot detector through a second converging lens to obtain a reference light spot; enabling the incident light to irradiate the wave plate on the wave plate placing table to obtain actually measured reflected light; converging the actually measured reflected light to a light spot detector through a second converging lens to obtain an actually measured light spot; adjusting the perpendicularity between the rotating shaft of the rotating table and the wave plate placing table based on the moving track of the actually measured light spot when the rotating table rotates, so that the rotating shaft of the rotating table is perpendicular to the wave plate placing table; and adjusting the inclination angle of the rotating shaft of the rotating table based on the relative position of the actually measured light spot and the reference light spot, so that the rotating shaft of the rotating table is parallel to the optical axis of the incident light. According to the invention, the phase retardation measurement precision of the wave plate can be effectively improved, and the error angle identification precision of the wave plate and the adjustment precision of the adjustment platform can be visually evaluated, so that the precision is ensured to meet the threshold requirement.

Description

Technical Field

[0001] The present invention relates to the field of optical detection technology, and in particular to a wave plate adjustment and measurement method and a measuring device. Background Art

[0002] Wave plates are a key component in the field of optics that can achieve functions such as light modulation, light splitting, and rectification. The measurement of the phase delay of wave plates has important applications in ensuring the polarization control of light, ensuring the normal operation of optical devices, and improving the precise measurement of physical quantities.

[0003] During the measurement process, the wave plate needs the incident light beam to be incident vertically onto the surface of the wave plate. The prior art usually lacks the adjustment of the wave plate to meet this measurement condition, resulting in low measurement accuracy of the phase delay of the wave plate. Therefore, it is necessary to provide a wave plate measurement method to improve the measurement accuracy of the phase delay of the wave plate.

[0004] In view of this, overcoming the defects of the prior art is an urgent problem to be solved in the field of this technology. Summary of the invention

[0005] The present invention provides a solution to the technical problem that there is a lack of effective means for adjusting the wave plate in the prior art, thereby resulting in low measurement accuracy of the phase delay amount of the wave plate.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a wave plate adjustment method, the wave plate adjustment method is used to adjust an adjustment platform on which a wave plate is placed, the adjustment platform comprising a rotating platform and a wave plate placement platform connected to the rotating platform, the wave plate adjustment method comprising:

[0008] Allow incident light to illuminate a corner cube prism to obtain reference reflected light, wherein the optical axis of the reference reflected light is parallel to the optical axis of the incident light;

[0009] Converging the reference reflected light to a light spot detector through a second converging lens to obtain a reference light spot;

[0010] Allowing incident light to illuminate the wave plate placed on the wave plate placement table to obtain measured reflected light;

[0011] Converging the measured reflected light to the light spot detector through the second converging lens to obtain a measured light spot;

[0012] Based on the running track of the measured light spot when the rotating stage rotates, adjusting the verticality between the rotating axis of the rotating stage and the wave plate placing stage so that the rotating axis of the rotating stage is perpendicular to the wave plate placing stage;

[0013] Based on the relative positions of the measured light spot and the reference light spot, the inclination angle of the rotation axis of the rotation stage is adjusted so that the rotation axis of the rotation stage is parallel to the optical axis of the incident light.

[0014] Preferably, the following steps are further included between obtaining the reference light spot and irradiating the wave plate placed on the wave plate placement table with the incident light:

[0015] The position of the light spot detector is adjusted so that the reference light spot is located at the center of the light spot detector.

[0016] Preferably, the adjusting the verticality between the rotation axis of the rotating table and the wave plate placement table based on the running trajectory of the measured light spot when the rotating table rotates, so that the rotation axis of the rotating table is perpendicular to the wave plate placement table, comprises:

[0017] Rotate the rotating table for at least one revolution to obtain a running track of the measured light spot, wherein the running track is annular;

[0018] Obtaining the center coordinates of the running trajectory and the coordinates of the measured light spot;

[0019] The verticality between the rotating axis of the rotating stage and the wave plate placement stage is adjusted to move the measured light spot until the distance between the coordinates of the measured light spot and the center coordinates of the running track reaches the minimum recognition distance of the light spot detector.

[0020] Preferably, adjusting the inclination angle of the rotation axis of the rotating stage based on the relative position of the measured light spot and the reference light spot so that the rotation axis of the rotating stage is parallel to the optical axis of the incident light comprises:

[0021] Acquiring the coordinates of the measured light spot and the coordinates of the reference light spot;

[0022] The tilt angle of the rotating axis of the rotating stage is adjusted to move the measured light spot until the distance between the coordinates of the measured light spot and the coordinates of the reference light spot reaches the minimum recognition distance of the light spot detector.

[0023] Preferably, the adjustment platform further comprises a second supporting base plate, a second adjustment plate connected to the rotating table, and at least three second adjustment screws disposed between the second supporting base plate and the second adjustment plate;

[0024] The step of adjusting the tilt angle of the rotating shaft of the rotating table comprises:

[0025] The second adjusting screw is adjusted to change the distance between the second adjusting plate and the second supporting substrate, thereby adjusting the inclination angle of the rotating axis of the rotating stage.

[0026] In a second aspect, the present invention provides a wave plate measurement method, comprising:

[0027] The adjustment platform is adjusted by the wave plate adjustment method described in the first aspect;

[0028] The wave plate placed on the adjustment platform is measured to obtain the phase delay of the wave plate.

[0029] Preferably, the following steps are further included between adjusting the adjustment platform and measuring the wave plate placed on the adjustment platform:

[0030] The error angle recognition accuracy of the wave plate and the adjustment accuracy of the adjustment platform are evaluated respectively;

[0031] The evaluation of the error angle recognition accuracy of the wave plate includes:

[0032] The incident light is made to illuminate the wave plate placed on the adjustment platform to obtain the measured reflected light, and the measured reflected light is converged to the light spot detector through the second converging lens to obtain the measured light spot;

[0033] The minimum recognition error angle α of the wave plate is calculated based on the following formula;

[0034] tan2α=Δx / f

[0035] in, Δ x is the minimum recognition spacing of the spot detector, and f is the focal length of the second converging lens;

[0036] Compare the minimum recognition error angle α with a threshold value to ensure that the minimum recognition error angle α is less than the threshold value;

[0037] The evaluation of the adjustment accuracy of the adjustment platform includes:

[0038] The minimum adjustment inclination angle β of the adjustment platform is calculated based on the following formula:

[0039] tanβ=ΔI / L

[0040] in, Δ I is the minimum adjustment distance of the first adjustment screw, L is the distance from the fulcrum of the first adjustment plate to the first adjustment screw, or, Δ I is the minimum adjustment distance of the second adjustment screw, and L is the distance from the fulcrum of the second adjustment plate to the second adjustment screw;

[0041] The minimum adjustment inclination angle β is compared with a threshold value to ensure that the minimum adjustment inclination angle β is smaller than the threshold value.

[0042] In a third aspect, the present invention provides a wave plate measuring device, comprising:

[0043] An illumination module, a beam splitter, a polarizing module, an adjustment platform, a polarization analyzing module, a spectrum detection module, a second converging lens and a light spot detector;

[0044] The lighting module is used to provide incident light;

[0045] The polarizing module, the adjusting platform, the analyzing module and the spectrum detecting module are sequentially arranged in the optical path of the incident light;

[0046] The adjustment platform is used to place a wave plate, and the incident light can generate reflected light after irradiating the wave plate;

[0047] The beam splitter is placed in the optical path of the reflected light, and the beam splitter is used to reflect the reflected light to the second converging lens;

[0048] The second converging lens is used to converge the reflected light to the light spot detector.

[0049] Preferably, the adjustment platform includes a rotating table and a wave plate placing table connected to the rotating table, a second supporting substrate, a second adjustment plate connected to the rotating table, and at least three second adjustment screws placed between the second supporting substrate and the second adjustment plate; wherein the wave plate placing table includes a first supporting substrate connected to the rotating table, a first adjustment plate, and at least three first adjustment screws placed between the first supporting substrate and the first adjustment plate.

[0050] In view of the deficiencies in the prior art, the beneficial effects that can be achieved by the present invention are as follows:

[0051] The present invention can make the incident light vertically incident on the surface of the wave plate by adjusting the position of the wave plate, and can effectively improve the measurement accuracy of the phase delay of the wave plate during the phase delay measurement of the wave plate; further, the present invention can intuitively evaluate the error angle recognition accuracy of the wave plate and the adjustment accuracy of the adjustment platform by using multiple precision evaluation methods to ensure that the accuracy meets the threshold requirement; further, the present invention also provides a wave plate measurement device that can accurately measure the phase delay of the wave plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0053] Figure 1 is a schematic flow chart of the wave plate adjustment method of this embodiment;

[0054] Figure 2 is a schematic diagram of the state when the coordinates of the reference light spot coincide with the center of the light spot detector during the adjustment process of this embodiment;

[0055] Figure 3 is a schematic diagram of the state when the rotating axis of the rotating table is perpendicular to the wave plate placement table during the adjustment process of this embodiment;

[0056] Figure 4 is a schematic diagram of the state when the rotation axis of the rotating stage is parallel to the optical axis of the incident light during the adjustment process of this embodiment;

[0057] Figure 5 Schematic diagram of the structure and measurement process of the wave plate measuring device in this embodiment;

[0058] Figure 6 is a schematic diagram of the process of evaluating the error angle recognition accuracy of the wave plate in this embodiment;

[0059] Figure 7 It is a schematic diagram of the process of evaluating the adjustment accuracy of the adjustment platform in this embodiment.

[0060] In the accompanying drawings, the same reference numerals are used to denote the same components or structures, wherein:

[0061] 10-illumination module, 101-light source, 102-collimating lens; 20-beam splitter; 30-polarizing module, 301-polarizer, 302-first compensator, 303-first motor; 40-wave plate; 50-adjustment platform, 501-first adjustment plate, 502-first adjustment screw, 503-first supporting substrate, 504-rotating table, 505-rotation axis, 506-second adjustment plate, 507-second adjustment screw, 508-second supporting substrate; 60-polarization analyzer module, 601-second motor, 602-second compensator, 603-polarization analyzer; 70-spectral detection module, 701-first converging lens, 702-spectrometer; 80-spot detection module, 801-second converging lens, 802-spot detector; 90-corner cone prism. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in 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. In addition, the technical features in the various embodiments or single embodiments provided by the present invention can be arbitrarily combined with each other to form a feasible technical solution. This combination is not subject to the constraints of the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0063] Embodiment 1:

[0064] In order to solve the technical problem that there is a lack of effective means for adjusting the wave plate in the prior art, resulting in low measurement accuracy of the phase delay of the wave plate, this embodiment 1 provides a wave plate adjustment method, which is used to adjust the adjustment platform on which the wave plate is placed, thereby achieving adjustment of the wave plate, the adjustment platform includes a rotating table and a wave plate placement table connected to the rotating table, the rotating table can rotate around its rotation axis, and during the rotation of the rotating table, the wave plate placement table is caused to rotate synchronously, such as Figure 1 As shown, Figure 1 : is a flow chart of the wave plate adjustment method, the wave plate adjustment method includes:

[0065] S10, making the incident light illuminate the corner cube prism to obtain reference reflected light, wherein the optical axis of the reference reflected light is parallel to the optical axis of the incident light.

[0066] In this step, the incident light may come from a lighting module, which includes components such as a light source and a collimating lens. After the incident light is emitted from the light source, it is collimated by the collimating lens to obtain a parallel light beam with good collimation for detection. The optical axis of the parallel light beam is the optical axis of the incident light. The corner cube prism is located on the propagation path of the parallel light beam. The corner cube prism can reflect the parallel light beam back along the original path to obtain a reference reflected light. At this time, the optical axis of the reference reflected light can be parallel to the optical axis of the incident light.

[0067] S20, converge the reference reflected light to the light spot detector through a second converging lens to obtain a reference light spot.

[0068] The reference reflected light is converged to the spot detector through the second converging lens, which can be achieved by utilizing the reflection function of the beam splitter, and the second converging lens and the spot detector can be included in an integrated spot detection module, the second converging lens is used to focus the reference reflected light, the spot detector is connected to the display end for communication, the display end is used to display the information of the reference spot, and the spot detector is used to receive the reference reflected light. When the reference reflected light enters the spot detector, the reference spot can be observed on the display end. Since the reference spot is generated by the reference reflected light parallel to the optical axis of the incident light, the reference spot has an indication function for the optical axis of the incident light and can be used as a reference for subsequent debugging steps.

[0069] S30, making the incident light illuminate the wave plate placed on the wave plate placement table to obtain the measured reflected light.

[0070] Wave plate is a key component in the field of optics. An important test item to measure whether the optical performance of the wave plate meets the requirements is the phase delay of the wave plate. In order to measure whether the phase delay of the wave plate meets the requirements, the wave plate is placed on the wave plate placement table during measurement; after the incident light is irradiated on the wave plate, the state of the incident light will change, and the measured reflected light will be obtained.

[0071] In actual application, since the second converging lens, the wave plate placement table and the wave plate itself may have slight errors in structure and size during manufacture, after the wave plate is placed on the wave plate placement table, the reference light spot may not be located at the center of the light spot detector. Therefore, in one preferred implementation, between obtaining the reference light spot (corresponding to S20) and irradiating the wave plate placed on the wave plate placement table with incident light (corresponding to S30), the following step is also included: adjusting the position of the light spot detector so that the reference light spot is located at the center of the light spot detector. By adjusting the reference light spot to the center of the light spot detector, the measurement range of the light spot detector can be increased, and the measured light spot generated by the measured reflected light can be prevented from falling outside the light spot detector.

[0072] like Figure 2 As shown, Figure 2 It is a schematic diagram of the state when the coordinates of the reference light spot coincide with the center of the light spot detector during the adjustment process.

[0073] S40, the measured reflected light is converged to the light spot detector through a second converging lens to obtain a measured light spot.

[0074] In S40 , the process of forming the measured light spot is substantially similar to the process of forming the reference light spot in S20 , and in this step, the process of forming the measured light spot is not described in detail.

[0075] S50, based on the running trajectory of the measured light spot when the rotating stage rotates, adjusting the verticality between the rotating axis of the rotating stage and the wave plate placing stage so that the rotating axis of the rotating stage is perpendicular to the wave plate placing stage.

[0076] In this step, based on the running track of the measured light spot when the rotating stage rotates, the verticality between the rotating axis of the rotating stage and the wave plate placement stage is adjusted so that the rotating axis of the rotating stage is perpendicular to the wave plate placement stage, which specifically includes:

[0077] S51, rotate the rotating table for at least one circle to obtain the running trajectory of the measured light spot. The running trajectory is a ring. This is because when the wave plate surface and the rotation axis of the rotating table are not perpendicular, during the rotation of the rotating table, the angle of the wave plate surface relative to the incident light will change periodically with the rotation of the rotating table, thereby causing the measured light spot to be periodically displaced with the rotation of the rotating table, and finally forming a ring-shaped running trajectory.

[0078] S52, obtaining the center coordinates of the running track and the coordinates of the measured light spot.

[0079] Since the running trajectory of the measured light spot is annular, in this step, the center coordinates of the running trajectory specifically refer to the center coordinates of the running trajectory of the measured light spot. Correspondingly, the coordinates of the measured light spot especially refer to the center (center) coordinates of the measured light spot.

[0080] S53, adjust the verticality between the rotating axis of the rotating table and the wave plate placement table to move the measured light spot, until the distance between the coordinates of the measured light spot and the center coordinates of the running track reaches the minimum recognition distance of the light spot detector. This is because when the wave plate surface and the rotating axis of the rotating table are in a completely vertical state, as the rotating table rotates, the angle of the wave plate surface relative to the incident light no longer changes. At this time, the measured light spot generated by the incident light will appear as a light spot, and the position of the light spot is the center (center of the circle) position of the annular running track. Therefore, by adjusting the coordinates of the measured light spot and the center coordinates of the running track to coincide, the wave plate surface and the rotating axis of the rotating table can be perpendicular to each other. The method of making the distance between the coordinates of the measured light spot and the center coordinates of the running track reach the minimum recognition distance of the light spot detector specifically includes the following steps:

[0081] Assume that before adjustment, the center coordinates of the incident light spot trajectory ring are (x1, y1), and after adjustment, the point coordinates are (x2, y2). The minimum recognition capability of the spot detector is 0.01mm. The minimum recognition capability of the spot detector can be obtained through the technical parameters of the spot detector. The 0.01mm given here is only an exemplary description. When |x2-x1|≤0.01mm and |y2-y1|≤0.01mm, the distance between the coordinates of the measured light spot and the center coordinates of the running trajectory reaches the minimum recognition distance of the spot detector. At this time, the coordinates of the measured light spot and the center coordinates of the running trajectory are basically in a coincidence state.

[0082] like Figure 3 As shown, Figure 3 This is a schematic diagram of the state when the rotating axis of the rotating stage is perpendicular to the wave plate placement stage during the adjustment process.

[0083] S60, based on the relative positions of the measured light spot and the reference light spot, adjusting the inclination angle of the rotation axis of the rotation stage so that the rotation axis of the rotation stage is parallel to the optical axis of the incident light.

[0084] Based on the relative positions of the measured light spot and the reference light spot, the inclination angle of the rotation axis of the rotating stage is adjusted so that the rotation axis of the rotating stage is parallel to the optical axis of the incident light, specifically including:

[0085] S61, obtaining the coordinates of the measured light spot and the coordinates of the reference light spot.

[0086] S62, adjust the inclination angle of the rotating axis of the rotating stage to move the measured light spot until the distance between the coordinates of the measured light spot and the coordinates of the reference light spot reaches the minimum recognition distance of the light spot detector. The adjustment steps involved in S61 and S62 are basically the same as the adjustment steps described in S53 above, so they will not be further described here. When the measured light spot coincides with the reference light spot, the reflected light corresponding to the measured light spot is the reference reflected light perpendicular to the optical axis of the incident light, and the reflected light is parallel to the incident light, which means that the wave plate surface is perpendicular to the incident light.

[0087] like Figure 4 As shown, Figure 4 This is a schematic diagram of the state when the rotation axis of the rotation stage is parallel to the optical axis of the incident light during the adjustment process.

[0088] It should be noted that, in actual application, the order of S50 and S60 can be interchanged. After current actual application and verification, S50 is placed before S60, which is a better order in actual operation. When both steps S50 and S60 are completed, the technical effect that the incident light can always be incident vertically on the surface of the wave plate during the rotation of the wave plate with the adjustment platform can be achieved, thereby ensuring the measurement accuracy of the phase delay of the wave plate.

[0089] The wave plate placement platform includes a first supporting substrate connected to the rotating platform, a first adjusting plate, and at least three first adjusting screws placed between the first supporting substrate and the first adjusting plate. During actual application, the wave plate is placed on the first adjusting plate. By adjusting any of the first adjusting screws, the verticality between the rotating axis of the rotating platform and the wave plate placement platform can be adjusted. Specifically, the verticality between the rotating axis of the rotating platform and the wave plate placement platform specifically refers to the verticality between the rotating axis of the rotating platform and the first adjusting plate.

[0090] In addition to the above-mentioned rotating table and the wave plate placement table connected to the rotating table, as one of the preferred implementations, in order to adjust the inclination angle of the rotating axis of the rotating table, the adjusting platform also includes a second supporting substrate, a second adjusting plate connected to the rotating table, and at least three second adjusting screws placed between the second supporting substrate and the second adjusting plate; specifically:

[0091] Adjusting the inclination angle of the rotating table's rotation axis includes:

[0092] The second adjusting screw is adjusted to change the distance between the second adjusting plate and the second supporting substrate, thereby adjusting the inclination angle of the rotating shaft of the rotating table.

[0093] This embodiment 1 provides a wave plate adjustment method, which can make the incident light vertically incident on the surface of the wave plate by adjusting the position of the wave plate. During the phase delay measurement process of the wave plate, the phase delay measurement accuracy of the wave plate can be effectively improved.

[0094] Embodiment 2:

[0095] Based on Example 1, this Example 2 provides a wave plate measurement method, including: adjusting the adjustment platform by using the wave plate adjustment method of Example 1; then, measuring the wave plate placed on the adjustment platform to obtain the phase delay of the wave plate.

[0096] When measuring the wave plate phase retardation, the light propagation path is as follows: Figure 1 The double-rotation ellipsometer method (other ellipsometers such as single-rotation ellipsometers are also feasible) is propagated as follows: the incident light from the light source passes through the collimating lens, is transmitted by the beam splitter, and is parallelly incident on the polarizer and the first compensator (controlled by the motor drive in the polarizing module), and then is incident on the surface of the wave plate to be measured. The wave plate is placed on the adjustment platform or adsorbed on the adjustment platform. The light transmitted from the wave plate passes through the second compensator (controlled by the motor drive in the analyzer module) and the analyzer, and is converged by the converging lens to be received by the spectrometer.

[0097] The spectrum of the wave plate to be tested is collected by a spectrometer and analyzed, and the phase delay of the wave plate can be calculated by combining the corresponding data processing. For example, Figure 1 In the embodiment, the phase delay of the wave plate to be measured can be obtained by collecting the Mueller matrix spectrum of the wave plate to be measured and using the relationship between the Mueller matrix and the phase and amplitude parameters. In order to ensure that the measurement accuracy of the phase delay of the wave plate meets the threshold requirement, in the specific implementation, the following steps are also included between adjusting the adjustment platform and measuring the wave plate placed on the adjustment platform: respectively evaluating the error angle recognition accuracy of the wave plate and the adjustment accuracy of the adjustment platform.

[0098] like Figure 6 As shown, Figure 6This is a schematic diagram of the process of evaluating the error angle recognition accuracy of the wave plate. The error angle recognition accuracy of the wave plate is evaluated, including:

[0099] The incident light is made to illuminate the wave plate placed on the adjustment platform to obtain the measured reflected light, and the measured reflected light is converged to the light spot detector through the second converging lens to obtain the measured light spot;

[0100] The minimum recognition error angle α of the wave plate is calculated based on the following formula, where the minimum error angle a refers to the angle between the wave plate surface and the wave plate reference plane with the center of the wave plate as the fulcrum, where the wave plate reference plane refers to the plane where the wave plate is located when the wave plate surface is perpendicular to the incident light;

[0101] tan2α=Δx / f

[0102] in, Δ x is the minimum recognition spacing of the spot detector, and f is the focal length of the second converging lens;

[0103] Compare the minimum recognition error angle α with the threshold to ensure that the minimum recognition error angle α is less than the threshold;

[0104] Take an example based on actual application scenarios. Suppose: the minimum recognition distance of the spot detector Δ x=0.01mm, the focal length of the second converging lens is selected to be the focal length of F90, that is, f=90mm, and α≈12.73″ is obtained by conversion, which is better than the threshold value 1′, that is, the error angle recognition accuracy of the wave plate meets the threshold requirement.

[0105] like Figure 7 As shown, Figure 7 This is a schematic diagram of the process of evaluating the adjustment accuracy of the adjustment platform. The evaluation of the adjustment accuracy of the adjustment platform includes:

[0106] The minimum adjustment inclination angle β of the adjustment platform is calculated based on the following formula:

[0107] tanβ=ΔI / L

[0108] in, Δ I is the minimum adjustment distance of the first adjustment screw, which is the distance adjusted by rotating the first adjustment screw one circle, L is the distance from the fulcrum of the first adjustment plate to the first adjustment screw, or, Δ I is the minimum adjustment distance of the second adjustment screw, which is the distance adjusted by rotating the second adjustment screw one circle; L is the distance from the fulcrum of the second adjustment plate to the second adjustment screw; the fulcrum in the present invention is usually another adjustment screw;

[0109] The minimum adjustment tilt angle β is compared with a threshold value to ensure that the minimum adjustment tilt angle β is smaller than the threshold value.

[0110] Take an example based on the actual application scenario, assuming that: the minimum adjustment distance of the first adjustment screw Δ I=0.025mm, the distance from the fulcrum of the first adjustment plate to the first adjustment screw L=100mm, and β≈0.86′ is obtained by conversion, which is better than the threshold value 1′, that is, the adjustment accuracy of the adjustment platform meets the threshold requirement.

[0111] This embodiment 2 provides a wave plate measurement method, which can intuitively evaluate the error angle recognition accuracy of the wave plate and the adjustment accuracy of the adjustment platform by using multiple precision evaluation methods, ensuring that the phase delay measurement accuracy of the wave plate meets the threshold requirements.

[0112] Embodiment 3:

[0113] Based on the embodiment 2, the embodiment 3 provides a wave plate measuring device, such as Figure 5 As shown, Figure 5 1 is a schematic diagram of the structure and measurement process of a wave plate measurement device, comprising: an illumination module 10, a spectroscope 20, a polarizing module 30, an adjustment platform 50, an analyzer module 60, a spectrum detection module 70, a second converging lens 801 and a spot detector 802 (spot detection module 80); the illumination module 10 is used to provide incident light, and the polarizing module 30, the adjustment platform 50, the analyzer module 60 and the spectrum detection module 70 are sequentially arranged in the optical path of the incident light; the adjustment platform 50 is used to place a wave plate 40, and the wave plate 40 itself is not a part of the device, and the incident light can generate reflected light after irradiating the wave plate 40; The optical mirror 20 is placed in the optical path of the reflected light. The beam splitter 20 has transmission and reflection functions, and is used to transmit the incident light to the polarizing module 30, and reflect the reflected light to the second converging lens 801; the second converging lens 801 is used to converge the reflected light to the spot detector 802, thereby realizing the visualization of the above-mentioned reference spot or measured spot. The spot detector 802 can be selected as a position sensitive detector (i.e. PSD), a four-quadrant detector (i.e. QD) or a charge coupled detector (i.e. CCD). In actual application, the spot detector 802 is preferably a four-quadrant detector (i.e. QD) because it is more intuitive and convenient.

[0114] In a specific implementation, the lighting module 10 includes a light source 101 and a collimating lens 102. The incident light is emitted from the light source 101 and is collimated by the collimating lens 102 before entering the polarizing module 30. The polarizing module 30 includes a polarizer 301, a first compensator 302 and a first motor 303. The first motor 303 is used to drive the first compensator 302. Similarly, the analyzing module 60 includes a second motor 601, a second compensator 602 and an analyzing module 603. The second motor 601 is used to drive the second compensator 602.

[0115] The adjustment platform 50 is a high-precision mechanical structure, which includes a rotating platform 504 and a wave plate placement platform connected to the rotating platform 504, a second support substrate 508, a second adjustment plate 506 connected to the rotating platform 504, and at least three second adjustment screws 507 placed between the second support substrate 508 and the second adjustment plate 506; wherein, the wave plate placement platform includes a first support substrate 503 connected to the rotating platform 504, a first adjustment plate 501, and at least three first adjustment screws 502 placed between the first support substrate 503 and the first adjustment plate 501. In specific applications, the rotating platform 504 can rotate around its rotation axis 505. When the rotating platform 504 rotates, the wave plate placement platform (i.e., the first support substrate 503, the first adjustment plate 501, and the first adjustment screws 502) rotate synchronously. When the polarization analyzer module 60 is connected, the second support substrate 508 is fixedly connected to the housing of the second motor 601 through the hole position set in the second support substrate 508.

[0116] The spectrum detection module 70 includes a first converging lens 701 and a spectrometer 702 . The incident light is converged by the first converging lens 701 and then received by the spectrometer 702 .

[0117] This embodiment 3 provides a wave plate measurement device, which can accurately measure the phase delay of the wave plate and has the advantages of convenient operation, high measurement efficiency and high measurement accuracy.

[0118] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

Claims

1. A wave plate adjustment method, characterized in that: The wave plate adjustment method is used to adjust an adjustment platform on which a wave plate is placed, wherein the adjustment platform includes a rotating platform and a wave plate placement platform connected to the rotating platform, and the wave plate adjustment method includes: Allow incident light to illuminate a corner cube prism to obtain reference reflected light, wherein the optical axis of the reference reflected light is parallel to the optical axis of the incident light; Converging the reference reflected light to a light spot detector through a second converging lens to obtain a reference light spot; Allowing incident light to illuminate the wave plate placed on the wave plate placement table to obtain measured reflected light; Converging the measured reflected light to the light spot detector through the second converging lens to obtain a measured light spot; Based on the running track of the measured light spot when the rotating stage rotates, adjusting the verticality between the rotating axis of the rotating stage and the wave plate placing stage so that the rotating axis of the rotating stage is perpendicular to the wave plate placing stage; Based on the relative positions of the measured light spot and the reference light spot, the inclination angle of the rotation axis of the rotation stage is adjusted so that the rotation axis of the rotation stage is parallel to the optical axis of the incident light.

2. The wave plate adjustment method according to claim 1, characterized in that The following steps are also included between obtaining the reference light spot and causing the incident light to illuminate the wave plate placed on the wave plate placement table: The position of the light spot detector is adjusted so that the reference light spot is located at the center of the light spot detector.

3. The wave plate adjustment method according to claim 1, characterized in that : The method of adjusting the verticality between the rotation axis of the rotating table and the wave plate placement table based on the running trajectory of the measured light spot when the rotating table rotates, so that the rotation axis of the rotating table is perpendicular to the wave plate placement table, comprises: Rotate the rotating table for at least one revolution to obtain a running track of the measured light spot, wherein the running track is annular; Obtaining the center coordinates of the running trajectory and the coordinates of the measured light spot; The verticality between the rotating axis of the rotating stage and the wave plate placement stage is adjusted to move the measured light spot until the distance between the coordinates of the measured light spot and the center coordinates of the running track reaches the minimum recognition distance of the light spot detector.

4. The wave plate adjustment method according to claim 1 or 2, characterized in that: The adjusting the inclination angle of the rotation axis of the rotating stage based on the relative position of the measured light spot and the reference light spot so that the rotation axis of the rotating stage is parallel to the optical axis of the incident light comprises: Acquiring the coordinates of the measured light spot and the coordinates of the reference light spot; The tilt angle of the rotating axis of the rotating stage is adjusted to move the measured light spot until the distance between the coordinates of the measured light spot and the coordinates of the reference light spot reaches the minimum recognition distance of the light spot detector.

5. The wave plate adjustment method according to claim 4, characterized in that: The adjustment platform further comprises a second support base plate, a second adjustment plate connected to the rotating platform, and at least three second adjustment screws disposed between the second support base plate and the second adjustment plate; The step of adjusting the tilt angle of the rotating shaft of the rotating table comprises: The second adjusting screw is adjusted to change the distance between the second adjusting plate and the second supporting substrate, thereby adjusting the inclination angle of the rotating axis of the rotating stage.

6. A wave plate measurement method, characterized in that: include: The adjustment platform is adjusted by the wave plate adjustment method as described in any one of claims 1 to 5; The wave plate placed on the adjustment platform is measured to obtain the phase delay of the wave plate.

7. The wave plate measurement method according to claim 6, characterized in that: The following steps are also included between adjusting the adjustment platform and measuring the wave plate placed on the adjustment platform: The error angle recognition accuracy of the wave plate and the adjustment accuracy of the adjustment platform are evaluated respectively; The evaluation of the error angle recognition accuracy of the wave plate includes: The incident light is made to illuminate the wave plate placed on the adjustment platform to obtain the measured reflected light, and the measured reflected light is converged to the light spot detector through the second converging lens to obtain the measured light spot; The minimum recognition error angle α of the wave plate is calculated based on the following formula; tan2α=Δx / f in, Δ x is the minimum recognition spacing of the spot detector, and f is the focal length of the second converging lens; Compare the minimum recognition error angle α with a threshold value to ensure that the minimum recognition error angle α is less than the threshold value; The evaluation of the adjustment accuracy of the adjustment platform includes: The minimum adjustment inclination angle β of the adjustment platform is calculated based on the following formula: tanβ=ΔI / L in, Δ I is the minimum adjustment distance of the first adjustment screw, L is the distance from the fulcrum of the first adjustment plate to the first adjustment screw, or, Δ I is the minimum adjustment distance of the second adjustment screw, and L is the distance from the fulcrum of the second adjustment plate to the second adjustment screw; The minimum adjustment inclination angle β is compared with a threshold value to ensure that the minimum adjustment inclination angle β is smaller than the threshold value.

8. A wave plate measuring device, characterized in that: include: An illumination module, a beam splitter, a polarizing module, an adjustment platform, a polarization analyzing module, a spectrum detection module, a second converging lens and a light spot detector; The lighting module is used to provide incident light; The polarizing module, the adjusting platform, the analyzing module and the spectrum detecting module are sequentially arranged in the optical path of the incident light; The adjustment platform is used to place a wave plate, and the incident light can generate reflected light after irradiating the wave plate; The beam splitter is placed in the optical path of the reflected light, and the beam splitter is used to reflect the reflected light to the second converging lens; The second converging lens is used to converge the reflected light to the light spot detector.

9. The wave plate measuring device according to claim 8, characterized in that: The adjustment platform includes a rotating table and a wave plate placement table connected to the rotating table, a second supporting substrate, a second adjustment plate connected to the rotating table, and at least three second adjustment screws placed between the second supporting substrate and the second adjustment plate; wherein the wave plate placement table includes a first supporting substrate connected to the rotating table, a first adjustment plate, and at least three first adjustment screws placed between the first supporting substrate and the first adjustment plate.

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