Microscopy system with focus offset compensation

Abstract

The utility model discloses a kind of focal point can be offset compensation's microscopic imaging system, comprising: including: focusing sensor component, microscopic imaging component and focusing optical path module, focusing sensor component is used to emit signal beam and receive sample feedback light beam, to realize focusing detection;Microscopic imaging component is used to image observation to sample;Focusing optical path module is set between focusing sensor component and microscopic imaging component, the state of signal beam is changed by adjusting the lens spacing of focusing optical path module, so that signal beam presents collimating state, convergent state or divergent state, the focusing focal plane of focusing sensor component and the observation focal plane of microscopic imaging component can be controlled separation, realize focal point can be offset compensation.The utility model can solve the problem of sample state interference when observation surface and focusing surface coincide, improve focusing accuracy, imaging definition.

Description

Technical Field

[0001] This invention belongs to the field of automatic focusing in optical microscopes, and specifically relates to a microscopic imaging system with focus offset compensation. Background Technology

[0002] Autofocus technology is a key technology in fields such as microscopy and precision machining. Its core function is to enable the imaging system to quickly and accurately lock the focus on the target observation surface through technical means, so as to obtain a clear image or achieve precise operation. Currently, autofocus technology is mainly divided into two categories: passive and active.

[0003] Passive focusing methods are based on image processing technology. They acquire corresponding images at different locations near the focal point, and then compare certain features of the acquired images with a reference target to determine the focal position of the sample, thereby achieving focusing.

[0004] Active autofocus achieves focusing by directly or indirectly detecting distance using auxiliary equipment, with the key being the measurement of focus offset. During focus search, it continuously compares in real-time the differences between certain features of the image acquired at the current position and the reference target to determine the direction and amount of focus movement, ultimately completing the focusing action.

[0005] In traditional autofocus applications, it is typically required that the sensor and the imaging lens assembly be focused on the same plane. However, in specific scenarios such as laser multifocal processing and deep structure imaging, the imaging lens assembly needs to perform focused observations inside the sample or below its surface. In these cases, traditional techniques reveal significant limitations.

[0006] On the one hand, if the focusing surface is uneven, or if the sample has low transmittance to the wavelength of the probe light used by the sensor, it will result in poor signal reception and weak energy from the sensor, significantly increasing the difficulty of autofocus. On the other hand, if there is a significant difference between the wavelengths of light used by the imaging lens group and the sensor, the different refractive properties of different wavelengths may cause a deviation between the focal plane of the imaging lens group and the focal plane of the sensor (i.e., focal plane difference), resulting in an unclear imaging effect of the imaging lens group, which seriously affects the measurement accuracy and operational reliability. Utility Model Content

[0007] To address the aforementioned technical problems, this invention proposes a focus-shiftable compensated microscopic imaging system.

[0008] To achieve the above objectives, the technical solution of this utility model is as follows:

[0009] This utility model discloses a focus-shiftable compensated microscopic imaging system, comprising:

[0010] A focus sensor assembly is used to emit a signal beam and receive a beam of light fed back from the sample in order to achieve focus detection;

[0011] Microscopic imaging components are used for imaging and observing samples;

[0012] A focusing optical path module is disposed between the focusing sensor assembly and the microscopic imaging assembly. The focusing optical path module includes at least two lenses with adjustable spacing.

[0013] By adjusting the lens spacing of the focusing optical path module, the state of the signal beam can be changed, making the signal beam collimated, converged, or divergent. This allows for the controllable separation of the focusing focal plane of the focusing sensor assembly from the observation focal plane of the microscopic imaging assembly, thus achieving focus shift compensation.

[0014] Based on the above technical solution, the following improvements can be made:

[0015] As a preferred embodiment, the focus sensor assembly includes:

[0016] A laser, used to emit a beam of signal;

[0017] The beam shaping module is used to collimate the signal beam emitted by the laser and focus the beam fed back from the sample to project onto the image sensor.

[0018] The first beam splitter is positioned between the laser and the beam shaping module. It is used to transmit the signal beam emitted by the laser to the beam shaping module and to reflect the feedback beam after it is reflected by the sample to the image sensor.

[0019] An image sensor is used to determine the focus status based on the spot characteristics of the feedback signal beam.

[0020] As a preferred embodiment, the microscopic imaging system further includes a second beam splitter, which is disposed between the focusing optical path module and the microscopic imaging component, for transmitting the signal beam output by the focusing optical path module to the microscopic imaging component, and for reflecting the feedback beam after being reflected by the sample to the microscopic imaging component.

[0021] As a preferred embodiment, the microscopic imaging component includes:

[0022] A microscope objective is used to focus the light beam output from the focusing optical path module onto the sample space.

[0023] The microscope and imaging camera are used in conjunction with the microscope objectives to image the sample.

[0024] As a preferred embodiment, the focusing optical path module includes: a positive lens and a negative lens with adjustable spacing.

[0025] As a preferred embodiment, the focusing optical path module includes: a first positive lens and a second positive lens with adjustable spacing.

[0026] This utility model discloses a focus-shiftable compensated microscopic imaging system, which has the following beneficial effects:

[0027] First, this invention incorporates a focusing optical path module between the focusing sensor assembly and the microscopic imaging assembly. This module can alter the state of the signal beam (e.g., convergence, collimation, divergence), allowing for controllable separation of the focusing focal plane of the focusing sensor assembly and the observation focal plane of the microscopic imaging assembly. Since the distance between the focusing and observation focal planes is fixed, the microscopic imaging assembly obtains a clear image when the focusing sensor assembly detects a clear spot. This design completely solves the problem of interference from the sample state when the observation and focusing planes coincide, significantly improving focusing accuracy and repeatability in complex scenarios such as laser multifocal processing and deep structure imaging.

[0028] Secondly, the focusing optical path module of this utility model is composed of several lenses with adjustable spacing, eliminating the need for complex precision driving components or additional optical path calibration components. Its structure has strong optical path compatibility with existing microscopic imaging systems and can be directly embedded between the focusing sensor component and the microscopic imaging component, without requiring large-scale modifications to the original system, significantly reducing integration difficulty and assembly costs. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the microscopic imaging system provided in an embodiment of the present invention.

[0031] Figure 2 The diagram shows the changes in the signal beam when the focusing optical path module provided in this embodiment of the utility model is a positive lens and a negative lens.

[0032] Figure 3 This is a schematic diagram illustrating the controllable separation of the focusing focal plane of the focusing sensor assembly and the observation focal plane of the microscopic imaging assembly provided in this embodiment of the present invention.

[0033] Figure 4 The diagram shows the change of the signal beam when the focusing optical path module provided in this embodiment of the utility model is a first positive lens and a second positive lens.

[0034] Wherein: 1-Laser, 2-Beam shaping module, 3-Focusing optical path module, 31-Positive lens, 32-Negative lens, 4-Image sensor, 51-First beam splitter, 52-Second beam splitter, 6-Microscope objective, 7-Tube lens, 8-Imaging camera, 9-Sample. Detailed Implementation

[0035] The preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0037] Using ordinal numbers such as “first,” “second,” “third,” etc. to describe ordinary objects merely indicates different instances of similar objects and is not intended to imply that the objects being described must have a given order in time, space, sequence, or any other way.

[0038] Furthermore, the expression "includes" is an "open-ended" expression, which means only that there is a corresponding component or step, and should not be interpreted as excluding additional components or steps.

[0039] To achieve the objectives of this invention, some embodiments of the focus-shiftable compensated microscopic imaging system, such as Figure 1 As shown, the microscopic imaging system includes: a focusing sensor assembly, a microscopic imaging assembly, and a focusing optical path module 3.

[0040] The focusing sensor assembly is used to emit a signal beam and receive the beam fed back from the sample to achieve focus detection. The microscopic imaging assembly is used to perform imaging observation of sample 9.

[0041] The focusing optical path module 3 is located between the focusing sensor assembly and the microscopic imaging assembly. The focusing optical path module 3 includes two lenses with adjustable spacing.

[0042] By adjusting the lens spacing of the focusing optical path module 3, the state of the signal beam is changed, making the signal beam collimated, converged, or divergent. This allows for the controllable separation of the focusing focal plane of the focusing sensor assembly from the observation focal plane of the microscopic imaging assembly, thus achieving focus shift compensation.

[0043] Specifically, in some embodiments, the focusing sensor assembly includes: a laser 1, a beam shaping module 2, a first beam splitter 51, an image sensor 4, etc.

[0044] Laser 1 is used to emit a signal beam; beam shaping module 2 is used to collimate the signal beam emitted by laser 1 and focus the beam fed back from the sample to project onto image sensor 4; first beam splitter 51 is disposed between laser 1 and beam shaping module 2, used to transmit the signal beam emitted by laser 1 to beam shaping module 2 and to reflect the feedback beam after reflection from the sample to image sensor 4; image sensor 4 is used to determine the focus state based on the spot characteristics of the feedback signal beam.

[0045] Furthermore, the microscopic imaging system also includes a second beam splitter 52, which is disposed between the focusing optical path module 3 and the microscopic imaging component, for transmitting the signal beam output by the focusing optical path module 3 to the microscopic imaging component, and for reflecting the feedback beam after being reflected by the sample to the microscopic imaging component.

[0046] The microscopic imaging assembly includes: a microscope objective 6, a tube lens 7, and an imaging camera 8; the microscope objective 6 is used to focus the light beam output from the focusing optical path module 3 onto the sample space; the tube lens 7 and the imaging camera 8 are used in conjunction with the microscope objective 6 to achieve imaging of the sample 9.

[0047] like Figure 2 As shown, the focusing optical path module 3 includes: a positive lens 31 and a negative lens 32 with adjustable spacing.

[0048] According to the formula for the focal length of a combined lens:

[0049]

[0050] in:

[0051] f is the total focal length of the lens group in focusing optical path module 3;

[0052] f1 is the focal length of the negative lens 32;

[0053] f2 is the focal length of the positive lens 31;

[0054] d is the distance between the positive lens 31 and the negative lens 32.

[0055] As can be seen from the above formula, when the focal length of each lens in the lens group is fixed, the total focal length of the optical path can be changed by adjusting the distance between two lenses, as follows.

[0056] When d = f1 + f2, f f The tendency to infinity means that the collimated beam remains a collimated beam after passing through the focusing optical path module 3.

[0057] When d > f1 + f2, f f A positive value means that the collimated beam becomes a converged beam after passing through the focusing optical path module 3;

[0058] When d < f1 + f2, f f A negative value means that the collimated beam becomes a divergent beam after passing through the focusing optical path module 3.

[0059] When light beams exiting at different angles pass through the microscope objective 6, the focusing position of the beam changes. The original focal plane is the position of the signal beam exiting the beam shaping module 2 and focusing directly through the microscope objective 6 without passing through the focusing optical path module 3. When the beam exits the focusing optical path module 3 in a collimated state, the focusing position after passing through the microscope objective 6 remains the original focal plane. When the beam exits the focusing optical path module 3 in a converging state, the focusing position after passing through the microscope objective 6 is closer to the objective than the original focal plane, resulting in upper defocus and an upper defocus plane. When the beam exits the focusing optical path module 3 in a diverging state, the focusing position after passing through the microscope objective 6 is farther from the objective than the original focal plane, resulting in lower defocus and a lower defocus plane.

[0060] In this embodiment, the microscopic imaging assembly consists of an infinitely conjugate microscope objective 6, a microscope tube 7, and a camera. During normal operation, the beam between the objective and the tube 7 is a collimated beam. At this time, the distance from the focal plane of the objective on the sample side to the lower end of the objective is the original back working distance set by the objective.

[0061] like Figure 3 As shown ( Figure 3 The upper surface of the sample (which is the focusing focal plane) is used as an example. Without loss of generality, taking the signal beam output from focusing optical path module 3 as a converging beam as an example, as previously analyzed, when the converging beam is incident on the microscope objective 6, the focusing plane on the sample side will be closer to the bottom of the objective. Therefore, by controlling the distance between the two lenses in focusing optical path module 3 and adjusting the exit angle of the signal beam output from focusing optical path module 3, the focusing plane of the signal beam can be adjusted to a suitable position, such as the upper surface of the sample, for focusing without affecting the observation of the microscope imaging optical path. Simultaneously, because the upper and lower surfaces of the sample are parallel, the distance between the focusing focal plane of the focusing sensor assembly and the observation focal plane of the microscope imaging assembly is fixed. Therefore, when the focusing sensor assembly finds a clear position on the focusing focal plane, the focusing position of the microscope imaging assembly is also a clear observation plane. This solves the problem of focusing accuracy when the observation focal plane and the focusing focal plane coincide and are both inside the sample.

[0062] To further optimize the implementation effect of this utility model, in some other embodiments, the remaining technical features are the same, the difference being that in other embodiments, such as... Figure 4 As shown, the focusing optical path module 3 includes a first positive lens and a second positive lens with adjustable spacing.

[0063] When the distance between the first positive lens and the second positive lens satisfies d = f1 + f2, d > f1 + f2, or d < f1 + f2, according to the focal length formula of the combined lens, the total focal length ff of the lens group can also achieve positive, negative, and infinite variations. That is, after the collimated beam passes through the focusing optical path module 3, it will achieve convergence, collimation, and divergence. In conjunction with the microscope objective 6, the effect of focal plane movement can also be achieved.

[0064] Where: f is the total focal length of the lens group in the focusing optical path module 3; f1 is the focal length of the first positive lens; f2 is the focal length of the second positive lens; and d is the distance between the first positive lens and the second positive lens.

[0065] In other embodiments, this invention also discloses a focus-shiftable compensated microscopic imaging method, which utilizes the aforementioned microscopic imaging system to achieve imaging, including the following:

[0066] Adjusting the lens spacing of the focusing optical path module 3 allows the output signal beam to be collimated, converged, or diverged. The focusing position of the signal beam after passing through the microscope objective 6 of the microscope imaging assembly changes as follows:

[0067] When the signal beam output by the focusing optical path module 3 is in a collimated state, the focusing position is the original focal plane;

[0068] When the signal beam output by the focusing optical path module 3 is in a converging state, the focusing position is closer to the microscope objective 6 than the original focal plane, forming an upper defocused focal plane.

[0069] When the signal beam output by the focusing optical path module 3 is in a divergent state, the focusing position is further away from the microscope objective 6 than the original focal plane, forming a lower defocused focal plane.

[0070] When the focusing sensor assembly detects a clear spot of light, the microscopic imaging assembly obtains a clear image.

[0071] Furthermore, when the microscopic imaging system includes: a laser 1, a beam shaping module 2, a focusing optical path module 3, an image sensor 4, a first beam splitter 51, a second beam splitter 52, a microscope objective 6, a tube mirror 7, and an imaging camera 8;

[0072] Microscopic imaging methods include:

[0073] Laser 1 emits a signal beam, which is transmitted to beam shaping module 2 via first beam splitter 51.

[0074] After collimating the signal beam, the beam shaping module 2 transmits it to the focusing optical path module 3;

[0075] Adjust the lens spacing of the focusing optical path module 3 so that the collimated signal beam is in a collimated state, a converged state, or a divergent state;

[0076] The signal beam output from the focusing optical path module 3 is transmitted to the microscope objective 6 via the second beam splitter 52 and focused into the sample space by the microscope objective 6.

[0077] The feedback beam, after being reflected by the sample, is split into two paths:

[0078] After passing through the microscope objective 6, the second beam splitter 52, the focusing optical path module 3, and the beam shaping module 2 in sequence, the beam is reflected by the first beam splitter 51 and projected onto the image sensor 4. The image sensor 4 determines the focus status based on the spot characteristics of the feedback beam and completes the focus detection.

[0079] The other path passes sequentially through the microscope objective 6, is reflected by the second beam splitter 52, and is then projected through the tube lens 7 onto the imaging camera 8 to achieve the imaging operation.

[0080] Furthermore, when the focusing optical path module 3 includes: a positive lens and a negative lens with adjustable spacing, or a first positive lens and a second positive lens with adjustable spacing,

[0081] The state of the signal beam can be changed by adjusting the distance d between the two lenses:

[0082] When d equals the sum of the focal lengths of the two lenses, the signal beam output by the focusing optical path module 3 is in a collimated state;

[0083] When d is greater than the sum of the focal lengths of the two lenses, the signal beam output by the focusing optical path module 3 converges.

[0084] When d is less than the sum of the focal lengths of the two lenses, the signal beam output by the focusing optical path module 3 exhibits a divergent state.

[0085] This utility model discloses a focus-shiftable compensated microscopic imaging system, which has the following beneficial effects:

[0086] First, this invention incorporates a focusing optical path module 3 between the focusing sensor assembly and the microscopic imaging assembly. This module 3 can alter the state of the signal beam (e.g., convergence, collimation, divergence), allowing for controllable separation of the focusing focal plane of the focusing sensor assembly and the observation focal plane of the microscopic imaging assembly. Since the distance between the focusing focal plane and the observation focal plane is fixed, the microscopic imaging assembly obtains a clear image when the focusing sensor assembly detects a clear spot. This design completely solves the problem of interference from the sample state when the observation and focusing planes coincide, significantly improving focusing accuracy and repeatability in complex scenarios such as laser multifocal processing and deep structure imaging.

[0087] Specifically, it has the following effects:

[0088] 1) This utility model can specifically solve the problem of focusing inside and on the lower surface of transparent samples.

[0089] Existing autofocus sensors, when used in assisted microscopic imaging systems to focus on the interior and lower surface of transparent samples, often suffer from poor signal reception and weak energy due to the sample's low transmittance to the probe light wavelength, making it difficult to accurately determine the focal point. This invention addresses this issue by incorporating a focusing optical path module 3 between the autofocus sensor and the microscope objective 6. This module adjusts the focal plane of the sensor's signal beam from the sample's interior and lower surface to a position with better signal reception, such as the sample's upper surface. Because the upper surface of the sample reflects the probe light more strongly and with more stable energy, the sensor can more clearly capture the light spot characteristics, thereby eliminating interference from poor signal and weak energy, and significantly improving the accuracy of light spot positioning.

[0090] 2) This utility model can achieve controllable separation of the focal plane, improving the focusing accuracy and repeatability in complex scenes.

[0091] In existing technologies, the focusing focal plane of an autofocus sensor typically coincides with the observation focal plane of a microscopic imaging optical path. When the observation surface is inside a sample, uneven sample surfaces directly affect the accuracy and repeatability of focusing. This invention adjusts the lens spacing in the focusing optical path module 3 to change the state of the signal beam (converging, collimating, diverging), enabling controllable separation between the focusing focal plane of the sensor signal beam and the observation focal plane of the microscopic imaging optical path. With a fixed separation distance, when the sensor finds a clear position on a more easily detectable focusing surface (such as the upper surface of the sample), the observation surface of the microscopic imaging system (inside the sample) will also be in focus. This design completely solves the problem of interference from the sample state when the observation surface and the focusing surface coincide, significantly improving the focusing accuracy and repeatability in complex scenarios such as laser multifocal processing and deep structure imaging.

[0092] 3) Ensure the coordination between focusing and imaging to optimize image quality.

[0093] When there is a difference in the wavelength of light used by the imaging lens assembly and the sensor, existing technologies are prone to focal plane aberration, resulting in a blurry image from the imaging lens assembly even when the sensor determines that the focus is clear. This invention, through a controllable focal plane separation mechanism, ensures that even with wavelength differences, as long as the sensor detects a clear light spot on the focusing plane, the microscopic imaging component can simultaneously obtain a clear image because the distance between the focusing plane and the observation plane is fixed. This effectively avoids the image quality problems caused by focal plane aberration and guarantees the stability of the imaging effect.

[0094] Secondly, the focusing optical path module 3 of this utility model is composed of several lenses with adjustable spacing, eliminating the need for complex precision driving components or additional optical path calibration components. Its structure has strong optical path compatibility with existing microscopic imaging systems and can be directly embedded between the focusing sensor component and the microscopic imaging component, without requiring large-scale modifications to the original system, significantly reducing integration difficulty and assembly costs.

[0095] In summary, this invention achieves controllable separation of the focal plane through the focusing optical path module 3, specifically solving problems such as weak focusing signals inside and on the lower surface of transparent samples, low focusing accuracy in complex scenes, and blurry images caused by poor focal planes. It fundamentally improves the focusing stability, accuracy, and imaging quality of the microscopic imaging system in special application scenarios.

[0096] In the description of this utility model, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "side", "top", "inner", "front", "center", "both ends", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0097] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0098] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A microscopic imaging system with focus offset compensation, characterized in that include: A focus sensor assembly is used to emit a signal beam and receive a beam of light fed back from the sample in order to achieve focus detection; Microscopic imaging components are used for imaging and observing samples; A focusing optical path module is disposed between the focusing sensor assembly and the microscopic imaging assembly, and the focusing optical path module includes: at least two lenses with adjustable spacing; By adjusting the lens spacing of the focusing optical path module, the state of the signal beam is changed, causing the signal beam to be collimated, converged, or diverged. This allows for the controllable separation of the focusing focal plane of the focusing sensor assembly from the observation focal plane of the microscopic imaging assembly, achieving focus shift compensation.

2. The microscopic imaging system of claim 1, wherein, The focusing sensor assembly includes: A laser, used to emit a beam of signal; A beam shaping module is used to collimate the signal beam emitted by the laser and focus the beam fed back from the sample to project onto the image sensor. The first beam splitter is positioned between the laser and the beam shaping module to allow the signal beam emitted by the laser to be transmitted to the beam shaping module and to reflect the feedback beam after being reflected by the sample to the image sensor. An image sensor is used to determine the focus status based on the spot characteristics of the feedback signal beam.

3. The microimaging system of claim 2, wherein, The microscopic imaging system further includes a second beam splitter, which is disposed between the focusing optical path module and the microscopic imaging component, for transmitting the signal beam output by the focusing optical path module to the microscopic imaging component, and for reflecting the feedback beam after being reflected by the sample to the microscopic imaging component.

4. The microscopic imaging system according to claim 1, characterized in that, The microscopic imaging component includes: A microscope objective lens is used to focus the light beam output from the focusing optical path module onto the sample space; The microscope and imaging camera are used in conjunction with the microscope objectives to image the sample.

5. The microscopic imaging system of claim 1, wherein, The focusing optical path module includes: a positive lens and a negative lens with adjustable spacing.

6. The microscopic imaging system of claim 1, wherein, The focusing optical path module includes: a first positive lens and a second positive lens with adjustable spacing.

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