Focal plane detection system and method

Abstract

The invention provides a focal plane detection system and method. The system comprises a first illumination module used for emitting a first light source signal; the first projection module comprises a first mark and is used for acquiring the first light source signal, and the first light source signal is converted into a first projection light signal after passing through the first mark; the carrying platform is used for carrying an object to be measured, the object to be measured is provided with a reflecting surface to be measured, and the first projection light signal is reflected by the reflecting surface to be measured to form a reflected light signal; the shielding module is used for shielding part of the reflected light signal to form a to-be-measured light signal; and the control module is used for generating a control signal based on the to-be-measured optical signal, and the control signal is used for controlling the carrying platform to move the to-be-measured reflecting surface to a focal plane. Based on the above system, determination of the out-of-focus direction does not need to be performed in advance, and determination of the focal plane position can be directly performed, so that the operation steps are simplified, and the convenience of focal plane detection is improved.

Description

Technical Field

[0001] This application relates to the field of optical inspection technology, and in particular to a focal plane inspection system and method. Background Technology

[0002] A projection lens is an instrument used for precision position detection. Before use, the focal plane position of the projection lens needs to be determined through focal plane detection. Focal plane detection technology enables non-contact real-time optical distance detection and is an important technology in the optical processing and inspection industry. It determines the focal plane position by adjusting the position of the reflective surface to be measured and aligning it with the focal plane.

[0003] However, existing focal plane detection systems or technologies require multiple adjustments to the position of the reflective surface being tested, making the operation cumbersome. Summary of the Invention

[0004] This application provides a focal surface detection system and method to solve the technical problem of cumbersome focal surface detection operation steps in the prior art.

[0005] In a first aspect, this application provides a focal plane detection system, comprising:

[0006] The first lighting module is used to emit the first light source signal;

[0007] A first projection module includes a first marker. The first projection module is used to acquire the first light source signal, and the first light source signal is converted into a first projection light signal after passing through the first marker.

[0008] A stage is used to support the object to be tested, which has a reflective surface to be tested. The first projected light signal is reflected by the reflective surface to be tested to form a reflected light signal.

[0009] An obstruction module is used to obstruct part of the reflected light signal to form the light signal to be measured.

[0010] The control module is used to generate a control signal based on the light signal to be tested, and the control signal is used to control the stage to move the reflective surface to be tested to the focal plane.

[0011] Furthermore, the first illumination module includes a first light source and a first collimating lens arranged at intervals along a direction perpendicular to the reflective surface to be tested; the first illumination module is used to emit a first light source signal; the first collimating lens is used to control the first light source signal to be perpendicular to the reflective surface to be tested, and to transmit the first light source signal to the first projection module.

[0012] Furthermore, the first projection module includes a first marking plate, a first projection lens, and a second projection lens arranged along a direction perpendicular to the reflective surface to be measured, and the first projection lens is disposed between the first marking plate and the second projection lens; the surface of the first marking plate has the first marking.

[0013] Furthermore, the system also includes a first beam splitter, which is disposed between the first projection lens and the second projection lens; the first beam splitter is used to reflect the reflected light signal to the blocking module.

[0014] Furthermore, the control module includes a first image sensor and a control terminal connected in communication; the control terminal is connected in communication with the platform.

[0015] The first image sensor and the control terminal are arranged at intervals along a direction parallel to the reflective surface to be measured;

[0016] The first image sensor is used to receive and generate a target light spot in the field of view of the first image sensor according to the light signal to be measured;

[0017] The control terminal is used to generate a control signal based on the positional deviation between the target light spot and the center of the field of view of the first image sensor.

[0018] Furthermore, the blocking module includes a blade and a first focusing lens; the blade is disposed between the first beam splitter and the first focusing lens, and is disposed on the side close to the stage, the blade is used to block part of the reflected light signal to form a light signal to be measured; the first focusing lens is used to focus the light signal to be measured and then transmit it to the control module.

[0019] Furthermore, the control signal includes a first control signal; the first image sensor has a field of view;

[0020] The field of view of the first image sensor includes a first region and a second region. The first region and the second region are located on both sides of the center of the field of view of the first image sensor and are arranged along a direction perpendicular to the reflective surface to be tested. The distance from the first region to the focal plane is greater than the distance from the second region to the focal plane. The control terminal is used to detect the position of the target light spot. When the target light spot is located in the first region, if it is determined that the distance from the reflective surface to be tested to the first projection module is less than the distance from the focal plane to the first projection module, the first control signal is generated. The first control signal is used to control the stage to move away from the first projection module along a direction perpendicular to the reflective surface to be tested.

[0021] Furthermore, the control signal also includes a second control signal; the control terminal is used to detect the position of the target light spot, and when the target light spot is located in the second region, if it is determined that the distance from the reflective surface to the first projection module is greater than the distance from the focal plane to the first projection module, then the second control signal is generated. The second control signal is used to control the stage to move along a direction perpendicular to the reflective surface to the test towards the side closer to the first projection module.

[0022] Furthermore, the reflective surface to be tested has a second mark;

[0023] The system further includes a second illumination module and a second projection module arranged at intervals; the second projection module includes a second marking plate and a third projection lens arranged at intervals along a direction perpendicular to the reflective surface to be measured; the second marking plate has a third marking;

[0024] The second illumination module is used to emit a second light source signal; the second light source signal is converted into a second projected light signal after passing through the second mark and the third projection lens; the second light source signal is converted into a third projected light signal after passing through the third projection lens and the third mark.

[0025] The control module is used to generate a control signal based on the second projection light signal and the third projection light signal;

[0026] The stage is used to execute the control signal, which controls the stage to move the reflective surface to be tested to the focal plane.

[0027] Furthermore, the second illumination module includes a second light source and a second collimating lens arranged in a direction parallel to the reflective surface to be measured; the second light source is used to emit a second light source signal; the second collimating lens is used to control the second light source signal to be parallel to the reflective surface to be measured.

[0028] Furthermore, the control module includes a second image sensor and a control terminal connected in communication; the control terminal is connected in communication with the platform.

[0029] The second marking plate is disposed between the third projection lens and the second image sensor;

[0030] The second image sensor is used to acquire the second projection light signal and the third projection light signal, and to generate a second projection image based on the second projection light signal and a third projection image based on the third projection light signal;

[0031] The control module is used to determine the positional deviation between the second projected image and the third projected image, and generate a control signal based on the positional deviation. The control signal is used to control the stage to move along a direction parallel to the reflective surface to be measured.

[0032] Secondly, this application proposes a focal plane detection method, which is applied to the focal plane detection system described in any of the above embodiments; the method includes:

[0033] Acquire the first light source signal;

[0034] The first light source signal is converted into a first projection light signal after passing through the first marker;

[0035] The first projected light signal is reflected by the reflective surface under test to form a reflected light signal;

[0036] The reflected light signal is partially blocked, forming the light signal to be measured.

[0037] A control signal is generated based on the light signal to be tested, and the control signal is used to control the stage to move the reflective surface to be tested to the focal plane.

[0038] This application can achieve the following beneficial effects:

[0039] In the focal plane detection system of this application, the light signal to be measured is obtained through the first projection module and the blocking module. The control module analyzes the light signal to be measured to obtain a control signal. The control signal is used to control the stage to move the reflective surface to be measured in the correct direction, so as to move the reflective surface to be measured to the focal plane and realize the determination of the focal plane position. This focal plane detection system does not require the prior judgment of the defocus direction and can directly determine the focal plane position, which simplifies the operation steps and improves the convenience of focal plane detection. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or 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 of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0041] Figure 1 A schematic diagram of a focal plane detection system provided for an embodiment of this application;

[0042] Figure 2 A schematic diagram of a field of view provided for an embodiment of this application;

[0043] Figure 3A schematic diagram of a field of view provided for an embodiment of this application;

[0044] Figure 4 A schematic diagram of a focal plane detection system and optical path provided for embodiments of this application;

[0045] Figure 5 A schematic diagram of a field of view provided for an embodiment of this application;

[0046] Figure 6 A schematic diagram of a focal plane detection system and optical path provided for embodiments of this application;

[0047] Figure 7 A schematic diagram of a field of view provided for an embodiment of this application;

[0048] Figure 8 A schematic diagram of a focal plane detection system and optical path provided for embodiments of this application;

[0049] Figure 9 A schematic diagram of an optical path provided for an embodiment of this application;

[0050] Figure 10 A schematic diagram of the structure of a focal plane detection system provided for an embodiment of this application;

[0051] Figure 11 This is a schematic flowchart of a focal plane detection method provided for an embodiment of this application.

[0052] Figure label:

[0053] 1. First illumination module; 101. First light source; 102. First collimating lens; 2. First projection module; 103. First marking plate; 104. First projection lens; 106. Second projection lens; 113. First mark; 105. First beam splitter; 107. Surface to be tested for reflection; 114. Second mark; 112. Stage; 3. Obstruction module; 108. Knife edge; 109. First focusing lens; 4. Control module; 110. First image sensor; 111. Control terminal; 123. Second image sensor; 5. Second illumination module; 115. Second light source; 116. Second collimating lens; 6. Second projection module; 120. Second marking plate; 119. Third projection lens; 121. Third mark; 122. Second focusing lens; 117. Second beam splitter; 118. Third beam splitter;

[0054] X, first direction; Y, second direction; Z, direction perpendicular to the reflective surface to be measured; P, position range of the focal plane. Detailed Implementation

[0055] The technical solutions of the embodiments of this application 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 application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0056] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] As described in the background section, a projection lens is an instrument used for precise position detection. Before use, the focal plane position of the projection lens needs to be determined through focal plane detection. Existing focal plane detection technologies first determine the defocus direction: by adjusting the position of the reflective surface to be tested, horizontal alignment is achieved, ensuring the mark on the reflective surface is located at the center of the focal plane detection lens's field of view. Then, the focal plane position is determined: the position of the reflective surface to be tested is adjusted multiple times until it coincides with the focal plane of the projection lens. This method requires multiple adjustments to the position of the reflective surface to be tested, making the operation cumbersome.

[0059] This application proposes a focal plane detection system and method, which can quickly determine the focal plane position of a projection lens and simplify the operation steps.

[0060] The following description, in conjunction with the accompanying drawings, introduces a focal plane detection system and method provided in this application.

[0061] See Figure 1As shown, this application proposes an embodiment of a focal plane detection system. The focal plane detection system is externally equipped with a projection lens and is used to determine the position of the focal plane of the projection lens. The focal plane detection system includes: a first illumination module 1, a first projection module 2, a stage 112, a blocking module 3, and a control module 4. The first illumination module 1 is used to emit a first light source signal. The first projection module 2 includes a first mark 113 and is used to acquire the first light source signal. The first light source signal is converted into a first projection light signal after passing through the first mark 113. The stage 112 is used to carry the object to be tested, which has a reflective surface 107 to be tested. The first projection light signal is reflected by the reflective surface 107 to form a reflected light signal. The blocking module 3 is used to block part of the reflected light signal, forming the light signal to be tested. The control module 4 is used to generate a control signal based on the light signal to be tested. The control signal is used to control the stage 112 to move the reflective surface 107 to the focal plane along a direction Z perpendicular to the reflective surface 107. After the movement is completed, the position of the reflective surface 107 is the position of the focal plane. The reflective surface 107 to be tested can be moved and adjusted within the position range P of the focal plane, and eventually coincide with the focal plane.

[0062] In some embodiments, see Figure 1 As shown, the first illumination module 1 includes a first light source 101 and a first collimating lens 102 arranged at Z intervals along a direction perpendicular to the reflective surface 107 to be measured; the first illumination module 1 is used to emit a first light source signal; the first collimating lens 102 is used to control the first light source signal to be perpendicular to the reflective surface 107 to be measured, that is, to collimate the first light source signal to convert the first light source signal into parallel light, and to transmit the first light source signal to the first projection module 2.

[0063] In some embodiments, see Figure 1 As shown, the first projection module 2 includes a first marker plate 103, a first projection lens 104, and a second projection lens 106 arranged along a direction Z perpendicular to the reflective surface 107 to be measured, with the first projection lens 104 disposed between the first marker plate 103 and the second projection lens 106; the surface of the first marker plate 103 has a first mark 113. A first light source signal illuminates and passes through the first mark 113, and is converted into a first projection light signal, which characterizes the position information of the first mark 113. The first projection lens 104 and the second projection lens 106 are used to project the first mark 113 onto the reflective surface 107 to be measured.

[0064] In some embodiments, see Figure 1 As shown, the system also includes a first beam splitter 105, which is disposed between the first projection lens 104 and the second projection lens 106. The first beam splitter 105 is used to change the transmission path of the reflected light signal and reflect the reflected light signal to the blocking module 3.

[0065] In some embodiments, see Figure 1 As shown, the control module 4 includes a first image sensor 110 and a control terminal 111 connected in communication; the control terminal 111 is connected in communication with the stage 112; the first image sensor 110 and the control terminal 111 are arranged at intervals along a direction parallel to the reflective surface 107 to be measured; the first image sensor 110 is used to receive and generate a target light spot in the field of view of the first image sensor 110 according to the light signal to be measured; the control terminal 111 is used to generate a control signal according to the positional deviation between the target light spot and the center of the field of view of the first image sensor 110.

[0066] In some embodiments, see Figure 1 As shown, the blocking module 3 includes a blade 108 and a first focusing lens 109. The blade 108 is positioned between the first beam splitter 105 and the first focusing lens 109, and is located on the side closest to the stage 112. The blade 108 is used to block part of the reflected light signal, forming the light signal to be measured. The first focusing lens 109 is used to focus the light signal to be measured and then transmit it to the control module 4. Specifically, the focused light signal to be measured enters the first image sensor 110. The blade 108 is positioned at the pupil surface of the first focusing lens 109.

[0067] In some embodiments, see Figure 2 As shown, the first image sensor 110 can image based on the light signal to be measured. The imaging area is called the field of view, and the geometric center of the field of view is called the field of view center. The field of view of the first image sensor 110 includes a first region and a second region. The first region and the second region are located on both sides of the center of the field of view of the first image sensor 110 and are arranged along the Z direction perpendicular to the reflective surface 107 to be measured. The distance from the first region to the focal plane is greater than the distance from the second region to the focal plane. The control signal includes a first control signal. The control terminal 111 is used to detect the position of the target light spot, see reference. Figure 3 As shown, when the target light spot is located in the first region, if the distance from the test reflective surface 107 to the first projection module 2 is determined to be less than the distance from the focal plane to the first projection module 2, a first control signal is generated. This first control signal controls the stage 112 to move along a direction Z perpendicular to the test reflective surface 107 towards the side away from the first projection module 2, i.e., downwards, so that the test reflective surface 107 coincides with the focal plane. If the distance from the test reflective surface 107 to the first projection module 2 is less than the distance from the focal plane to the first projection module 2 (the test reflective surface 107 is located above the focal plane), its optical path diagram is as follows. Figure 4 As shown, the first mark 113 appears as a blurred image on the test reflective surface 107. Furthermore, the greater the distance from the test reflective surface 107 to the focal plane, the larger the target spot size, and the further the target spot is from the center of the field of view. When the target spot is located in the first region, the target spot is semi-circular.

[0068] In some embodiments, the control signal further includes a second control signal. The control terminal 111 is used to detect the position of the target light spot; if the target light spot is located in the second region, refer to... Figure 5 As shown, if the distance from the test reflective surface 107 to the first projection module 2 is determined to be greater than the distance from the focal plane to the first projection module 2, a second control signal is generated. This second control signal controls the stage 112 to move along a direction Z perpendicular to the test reflective surface 107 towards the side closer to the first projection module 2, i.e., upwards, so that the test reflective surface 107 coincides with the focal plane. If the distance from the test reflective surface 107 to the first projection module 2 is greater than the distance from the focal plane to the first projection module 2 (the test reflective surface 107 is located below the focal plane), its optical path diagram is as follows. Figure 6 As shown, the first mark 113 appears as a blurred image on the test reflective surface 107. Furthermore, the greater the distance from the test reflective surface 107 to the focal plane, the larger the target spot size, and the further the target spot is from the center of the field of view. When the target spot is located in the second region, the target spot is semi-circular.

[0069] In some embodiments, if the target spot is located at the center of the field of view, refer to Figure 7 As shown, this indicates that the reflective surface 107 under test coincides with the focal plane and no adjustment is required. The optical path diagram at this time is as follows. Figure 8 As shown, the first mark 113 forms a clear image on the reflective surface 107 under test. When the target spot is located at the center of the field of view, the target spot appears circular.

[0070] In some embodiments, see Figure 9 As shown, the first projected light signal illuminates the reflective surface 107 to be tested and is reflected at the reflective surface 107 to obtain the reflected light signal. The reflected light signal is refracted by the first beam splitter 105, causing its propagation path to be deflected, resulting in the light signal to be tested. The optical path of the first projected light signal introduces a distance error of 1x, and the optical path of the reflected light signal introduces a distance error of 1x. Therefore, the light signal to be tested carries a distance error of 2x, amplifying the distance error and making it easier to detect small distance errors, thereby improving the accuracy of focal plane detection. The distance error refers to the distance difference between the reflective surface 107 to be tested and the focal plane.

[0071] Based on the above embodiments, it is not necessary to determine the defocus direction in advance, and the focal plane position can be determined directly. This enables the alignment (overlap) of the reflective surface 107 to be tested with the focal plane in the vertical direction (i.e., the direction Z perpendicular to the reflective surface 107 to be tested). This simplifies the operation steps, improves the convenience of focal plane detection, and the surface of the reflective surface 107 to be tested does not need to be marked, thus avoiding damage to the integrity of the reflective surface 107 to be tested. There are also no restrictions on the size of the projection lens.

[0072] In some embodiments, the blade 108 may also be positioned between the first beam splitter 105 and the first focusing lens 109, and positioned on the side away from the stage 112. In this case, the control terminal 111 detects the position of the target light spot. If the target light spot is located in the first region, and it is determined that the distance from the test reflective surface 107 to the first projection module 2 is greater than the distance from the focal plane to the first projection module 2, a second control signal is generated. The second control signal is used to control the stage 112 to move along the direction Z perpendicular to the test reflective surface 107 towards the side closer to the first projection module 2. If the target light spot is located in the second region, and it is determined that the distance from the test reflective surface 107 to the first projection module 2 is less than the distance from the focal plane to the first projection module 2, a first control signal is generated. The first control signal is used to control the stage 112 to move along the direction Z perpendicular to the test reflective surface 107 towards the side away from the first projection module 2.

[0073] In some embodiments, see Figure 10 As shown, the reflective surface 107 under test has a second mark 114; the system also includes a second illumination module 5 and a second projection module 6 arranged at intervals; the second projection module 6 includes a second mark plate 120 and a third projection lens 119 arranged at intervals along a direction Z perpendicular to the reflective surface 107 under test; the second mark plate 120 has a third mark 121; the second illumination module 5 is used to emit a second light source signal; the second light source signal is converted into a second projection light signal after passing through the second mark 114 and the third projection lens 119; the second light source signal is converted into a third projection light signal after passing through the third projection lens 119 and the third mark 121; the second projection light signal and the third projection light signal are received by the control module 4; the control module 4 is used to generate a control signal based on the second projection light signal and the third projection light signal; the stage 112 is used to execute the control signal, and the control signal is used to control the stage 112 to move the reflective surface 107 under test along a direction parallel to the reflective surface 107 under test to the focal plane.

[0074] In some embodiments, see Figure 10 As shown, the second illumination module 5 includes a second light source 115 and a second collimating lens 116 arranged in a direction parallel to the reflective surface 107 to be measured; the second light source 115 is used to emit a second light source signal; the second collimating lens 116 is used to control the second light source signal to be parallel to the reflective surface 107 to be measured.

[0075] In some embodiments, see Figure 10As shown, the control module 4 includes a second image sensor 123 and a control terminal 111 connected in communication; the control terminal 111 is connected in communication with the stage 112; a second marker plate 120 is disposed between the third projection lens 119 and the second image sensor 123; the second image sensor 123 is used to acquire a second projection light signal and a third projection light signal, and generate a second projection image based on the second projection light signal and a third projection image based on the third projection light signal; the control module 4 is used to determine the positional deviation between the second projection image and the third projection image, and generate a control signal based on the positional deviation, the control signal being used to control the stage 112 to move along a direction parallel to the reflective surface 107 to be measured. Specifically, the control terminal 111 in the control module 4 is used to determine the positional deviation between the second projection image and the third projection image, and generate a control signal based on the positional deviation.

[0076] For details, please refer to Figure 10 As shown, the focal plane detection system has a first direction X and a second direction Y that are perpendicular to each other. The first direction X is parallel to the reflective surface 107 to be tested, and the second direction Y is also parallel to the reflective surface 107 to be tested. The second image sensor 123 has a field of view. The second image sensor 123 can image a second projected image based on a second projected light signal within the field of view, and image a third projected image based on a third projected light signal. The control terminal 111 is used to determine the positional deviation between the second projected image and the third projected image, and generate a control signal (e.g., a third control signal) based on the positional deviation. When the second projected image is to the left of the third projected image, the third control signal is used to control the stage 112 to move to the right (along the first direction X) so that the second projected image coincides with the third projected image, thereby achieving the alignment of the reflective surface 107 to be tested with the focal plane. When the second projected image is to the right of the third projected image, the third control signal is used to control the stage 112 to move to the left (along the first direction X) so that the second projected image coincides with the third projected image, thereby achieving the alignment of the reflective surface 107 to be tested with the focal plane. When the second projected image is above the third projected image, the third control signal controls the stage 112 to move forward (along the second direction Y) so that the second projected image coincides with the third projected image, thereby achieving the alignment of the reflective surface 107 under test with the focal plane. When the second projected image is below the third projected image, the third control signal controls the stage 112 to move backward (along the second direction Y) so that the second projected image coincides with the third projected image, thereby achieving the alignment of the reflective surface 107 under test with the focal plane.

[0077] Based on the above embodiments, the reflective surface 107 to be tested can be controlled to move along the first direction X and the second direction Y (i.e., the horizontal direction), thereby achieving alignment between the reflective surface 107 to be tested and the focal plane in the horizontal direction.

[0078] In some embodiments, the upper surface of the second marker plate 120 is parallel to the focal plane, and the third marker 121 is located on the upper surface of the second marker plate 120, so the focal plane can be aligned in the horizontal direction using the third marker 121.

[0079] In some embodiments, the upper surface of the first marking plate 103 is parallel to the focal plane, and the first mark 113 is located on the upper surface of the first marking plate 103.

[0080] In some embodiments, the focal plane detection system further includes a third beam splitter 118, a second beam splitter 117, and a second focusing lens 122. The third beam splitter 118 is used to change the propagation direction of the first projected light signal and is disposed between the first beam splitter 105 and the first focusing lens 109. The second beam splitter 117 is used to change the propagation path of the second light source signal to transmit the second light source signal to the reflective surface 107 to be measured. The second beam splitter 117 is disposed between the first beam splitter 105 and the third projected lens 119. The second focusing lens 122 is used to focus the second and third projected light signals before transmitting them to the second image sensor 123.

[0081] In some embodiments, the first light source 101 and the second light source 115 can be polarized light sources or unpolarized light sources.

[0082] In some embodiments, the first beam splitter 105, the second beam splitter 117, and the third beam splitter 118 are semi-reflective and semi-transparent prisms, with their middle bevels coated with a 50% transmission and 50% reflection film. The film can be a bandpass filter or a polarization filter.

[0083] This application proposes an embodiment of a focal plane detection method, see reference. Figure 11 As shown, the focal plane detection method is applied to any of the above-described focal plane detection systems, including:

[0084] S101: Acquire the first light source signal;

[0085] S102: The first light source signal is converted into a first projection light signal after passing through the first marker;

[0086] S103: The first projected light signal is reflected by the reflective surface to be tested to form a reflected light signal;

[0087] S104: Partially blocking the reflected light signal to form the light signal to be measured;

[0088] S105: Generate a control signal based on the light signal to be measured. The control signal is used to control the stage to move the reflective surface to be measured to the focal plane.

[0089] It should be noted that the above method may include other implementation methods according to the description of the system embodiments. For specific implementation methods, please refer to the description of the relevant system embodiments, which will not be elaborated here.

[0090] The 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 any creative effort.

[0091] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0092] In summary, although the present application has disclosed the preferred embodiments as described above, the above preferred embodiments are not intended to limit the present application. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be determined by the scope defined in the claims.

Claims

1. A focal plane detection system, characterized in that, include: The first lighting module (1) is used to transmit the first light source signal; The first projection module (2) includes a first marker (113). The first projection module (2) is used to acquire the first light source signal. The first light source signal is converted into a first projection light signal after passing through the first marker (113). A stage (112) is used to carry the object to be tested. The object to be tested has a test reflective surface (107). The first projected light signal is reflected by the test reflective surface (107) to form a reflected light signal. The blocking module (3) is used to block part of the reflected light signal to form the light signal to be measured; The control module (4) is used to generate a control signal based on the light signal to be tested. The control signal is used to control the stage (112) to move the reflective surface (107) to the focal plane.

2. The system according to claim 1, characterized in that, The first illumination module (1) includes a first light source (101) and a first collimating lens (102) arranged at intervals along a direction (Z) perpendicular to the reflective surface (107) to be tested; the first illumination module (1) is used to emit a first light source signal; the first collimating lens (102) is used to control the first light source signal to be perpendicular to the reflective surface (107) to be tested, and to transmit the first light source signal to the first projection module (2).

3. The system according to claim 1, characterized in that, The first projection module (2) includes a first marking plate (103), a first projection lens (104), and a second projection lens (106) arranged along a direction (Z) perpendicular to the reflective surface (107) to be tested, and the first projection lens (104) is disposed between the first marking plate (103) and the second projection lens (106); the surface of the first marking plate (103) has the first mark (113).

4. The system according to claim 3, characterized in that, The system further includes a first beam splitter (105), which is disposed between the first projection lens (104) and the second projection lens (106); the first beam splitter (105) is used to reflect the reflected light signal to the blocking module (3).

5. The system according to claim 1, characterized in that, The control module (4) includes a first image sensor (110) and a control terminal (111) connected in communication; the control terminal (111) is connected in communication with the platform (112); The first image sensor (110) and the control terminal (111) are arranged at intervals along a direction parallel to the reflective surface (107) to be measured; The first image sensor (110) is used to receive and generate a target light spot in the field of view of the first image sensor (110) according to the light signal to be measured; The control terminal (111) is used to generate a control signal based on the positional deviation between the target light spot and the field of view center of the first image sensor (110).

6. The system according to claim 4, characterized in that, The blocking module (3) includes a blade (108) and a first focusing lens (109); the blade (108) is disposed between the first beam splitter (105) and the first focusing lens (109), and is disposed on the side close to the stage (112). The blade (108) is used to block part of the reflected light signal to form the light signal to be measured; the first focusing lens (109) is used to focus the light signal to be measured and then transmit it to the control module (4).

7. The system according to claim 5, characterized in that, The control signal includes a first control signal; the first image sensor (110) has a field of view; The field of view of the first image sensor (110) includes a first region and a second region. The first region and the second region are located on both sides of the center of the field of view of the first image sensor (110) and are arranged in a direction (Z) perpendicular to the reflective surface (107) to be measured. The distance from the first region to the focal plane is greater than the distance from the second region to the focal plane. The control terminal (111) is used to detect the position of the target light spot. When the target light spot is located in the first area, if it is determined that the distance from the test reflective surface (107) to the first projection module (2) is less than the distance from the focal plane to the first projection module (2), the first control signal is generated. The first control signal is used to control the stage (112) to move away from the first projection module (2) along the direction (Z) perpendicular to the test reflective surface (107).

8. The system according to claim 7, characterized in that, The control signal also includes a second control signal; The control terminal (111) is used to detect the position of the target light spot. When the target light spot is located in the second area, if it is determined that the distance from the test reflective surface (107) to the first projection module (2) is greater than the distance from the focal plane to the first projection module (2), then the second control signal is generated. The second control signal is used to control the stage (112) to move along the direction (Z) perpendicular to the test reflective surface (107) towards the side closer to the first projection module (2).

9. The system according to claim 1, characterized in that, The reflective surface to be tested (107) has a second mark (114); The system also includes a second illumination module (5) and a second projection module (6) arranged at intervals; the second projection module (6) includes a second marking plate (120) and a third projection lens (119) arranged at intervals along a direction (Z) perpendicular to the reflective surface (107) to be tested; the second marking plate (120) has a third mark (121); The second lighting module (5) is used to emit a second light source signal; the second light source signal is converted into a second projection light signal after passing through the second mark (114) and the third projection lens (119); the second light source signal is converted into a third projection light signal after passing through the third projection lens (119) and the third mark (121); The control module (4) is used to generate a control signal based on the second projection light signal and the third projection light signal; The stage (112) is used to execute the control signal, which controls the stage (112) to move the reflective surface (107) to be tested to the focal plane.

10. The system according to claim 9, characterized in that, The second illumination module (5) includes a second light source (115) and a second collimating lens (116) arranged in a direction parallel to the reflective surface (107) to be tested; the second light source (115) is used to emit a second light source signal; the second collimating lens (116) is used to control the second light source signal to be parallel to the reflective surface (107) to be tested.

11. The system according to claim 9, characterized in that, The control module (4) includes a second image sensor (123) and a control terminal (111) connected in communication; the control terminal (111) is connected in communication with the platform (112); The second marking plate (120) is disposed between the third projection lens (119) and the second image sensor (123); The second image sensor (123) is used to acquire the second projection light signal and the third projection light signal, and generate a second projection image based on the second projection light signal and a third projection image based on the third projection light signal; The control module (4) is used to determine the positional deviation between the second projection image and the third projection image, and generate a control signal based on the positional deviation. The control signal is used to control the stage (112) to move along a direction parallel to the reflective surface (107) to be tested.

12. A method for detecting focal planes, characterized in that, The method is applied to the focal plane detection system as described in any one of claims 1 to 11, and the method comprises: Acquire the first light source signal; The first light source signal is converted into a first projection light signal after passing through the first mark (113); The first projected light signal is reflected by the reflective surface (107) to form a reflected light signal; The reflected light signal is partially blocked, forming the light signal to be measured. A control signal is generated based on the light signal to be tested. The control signal is used to control the stage (112) to move the reflective surface (107) to be tested to the focal plane.

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