CN115437099A - Automatic focusing optical system and focusing method - Google Patents

Abstract

The invention discloses an automatic focusing optical system and a focusing method. An automatic focusing optical system is characterized by comprising a differential interference optical module, a liquid focusing module, a processing module and a driving module; the differential interference optical module is used for emitting a detection beam to detect an object to be detected and acquiring a detection image; the liquid focusing module is arranged in the light path of the differential interference optical module; the processing module is respectively electrically connected with the differential interference optical module and the driving module and is used for determining the defocusing information of the image to be detected according to the detected image, determining the adjustment information of the liquid focusing module according to the defocusing information and sending the adjustment information to the driving module; the driving module is electrically connected with the liquid focusing module and used for adjusting the diopter of the liquid focusing module according to the adjusting information. The invention utilizes the liquid lens to change the focal length in the automatic focusing optical system, eliminates the abrasion caused by mechanical movement, and has the advantages of low noise, good stability and high response speed.

Description

A kind of automatic focusing optical system and focusing method

technical field

The invention relates to the field of optical technology, in particular to an automatic focusing optical system and a focusing method.

Background technique

Due to its special structure, the differential interference imaging system is suitable for detecting the structure and defects of transparent objects and samples with extremely small height differences, including cells, metallographic structures, conductive particles of liquid crystal screens, lines and magnetic heads of capacitive touch screens, Widely used in biomedical, liquid crystal panel detection and other fields.

In the existing technology, the differential interference imaging detection system usually has two methods of manual focus and automatic focus. The existing automatic focus technology usually drives the overall axial movement of the optical system by a motor, that is, to adjust the working distance.

However, in the existing autofocus technology, the mechanical reciprocating movement of the optical system will cause wear and tear, and the motor-driven focusing speed is not particularly fast, and motor noise will also be introduced.

Contents of the invention

The invention provides an automatic focusing optical system and a focusing method to solve the problems of slow focusing speed of mechanical focusing and introduction of motor noise.

According to one aspect of the present invention, an autofocus optical system is provided, which includes a differential interference optical module, a liquid focusing module, a processing module and a driving module;

The differential interference optical module is used to emit a detection beam to detect the object to be detected and obtain a detection image;

The liquid focusing module is arranged in the optical path of the differential interference optical module;

The processing module is electrically connected to the differential interference optical module and the driving module, and is used to determine the defocus information of the image to be detected according to the detection image, and determine the liquid focus module according to the defocus information and send the adjustment information to the drive module;

The driving module is electrically connected to the liquid focusing module, and is used for adjusting the diopter of the liquid focusing module according to the adjustment information.

Optionally, the differential interference optical module includes a light source unit, a polarizing unit, a differential interference unit, an objective lens unit, an eyepiece unit, a filter unit, an analyzer unit, an imaging position adjustment unit, and an imaging unit;

The liquid focusing module is located in the optical path between the differential interference unit and the eyepiece;

The light source unit includes a first light source and a second light source, the first light source is used to emit a first detection beam, the second light source is used to emit a second detection beam, the first detection beam and the second The wavelength range of the probe beam is different;

The polarizing units are respectively located on the propagation paths of the first detection beam and the second detection beam, and are used for modulating the first detection beam to form a first polarized detection beam, and modulating the second detection beam to form a second polarized detection beam. Two polarized probe beams;

The differential interference unit is respectively located on the propagation paths of the first polarized detection beam and the second probe beam, and is used for modulating the first polarized detection beam to form a first differentially polarized detection beam, and modulating the second polarized detection beam the probe beam forms a second differentially polarized probe beam;

The objective lens unit and the object to be detected are sequentially located on the transmission paths of the first differentially polarized detection beam and the second differentially polarized detection beam, and the first differentially polarized detection beam is reflected by the object to be detected forming a first differentially polarized reflected light beam, the first differentially polarized reflected light beam is sequentially modulated by the objective lens and the differential interference unit to form a first imaging light beam, and the first imaging light beam carries a detection signal of the object to be detected ; The second differentially polarized detection beam is reflected by the object to be detected to form a second differentially polarized reflected beam, and the second differentially polarized reflected beam is sequentially modulated by the objective lens unit and the differential interference unit to form a second differentially polarized reflected beam an imaging beam, the second imaging beam carrying a detection signal of the object to be detected;

The liquid focusing module is respectively located on the propagation paths of the first imaging beam and the second imaging beam, and is used to adjust the focal length of the first imaging beam and the second imaging beam;

The filtering unit includes a first filtering lens and a second filtering lens, and the filtering ranges of the first filtering lens and the second filtering lens are different; the analyzing unit includes a first analyzing lens and a second analyzing lens The imaging unit includes a first imaging unit and a second imaging unit; the first imaging light beam passes through the eyepiece unit, the first filter lens, the first analyzer lens, and the imaging position adjustment unit in sequence Imaging at the first position and the second position of the first imaging unit, the first position and the second position are symmetrical to the image plane conjugate to the second imaging unit; the second imaging light beam After sequentially passing through the eyepiece, the second filter lens and the second analyzer lens, the image is formed in the second imaging unit.

Optionally, the differential interference optical module further includes a mask pattern unit;

The mask pattern unit is located on the propagation path of the first detection beam, and is used for modulating the first detection beam to form a pattern detection beam.

Optionally, the mask pattern unit includes a grating component.

Optionally, the imaging position adjustment unit includes a first lens mirror and a first mirror;

The first imaging light beam is transmitted by the first mirror sheet and then enters the first position, is reflected by the first mirror sheet, and then is reflected by the first mirror sheet and then enters the second position. Location.

Optionally, the differential interference optical module further includes a second mirror and a third mirror;

The second reflective sheet is located in the optical path between the polarizing unit and the differential interference unit and in the optical path between the differential interference unit and the liquid focusing module, and is used to reflect the first polarization The detection beam and the second polarized detection beam are sent to the differential interference unit, and the first imaging beam and the second imaging beam are transmitted to the liquid focusing module;

The third lens mirror is located in the optical path between the eyepiece unit and the filter unit, and is used to reflect the first imaging light beam and the second imaging light beam to the first filter lens, transmit the The first imaging light beam and the second imaging light beam are sent to the second filter lens.

Optionally, the differential interference optical module further includes a second reflective sheet and a fourth transflective sheet;

The second reflective sheet is located in the optical path between the first light source and the fourth reflective sheet for reflecting the first detection beam to the fourth reflective sheet;

The fourth mirror is located in the optical path between the second reflective sheet and the polarizing unit and in the optical path between the second light source and the polarizing unit, and is used to transmit the first detection beam to the polarizing unit, reflecting the second detection beam to the polarizing unit.

Optionally, the liquid focus module includes a first outer shell and a second outer shell that are oppositely arranged;

a first protective layer and a second protective layer arranged in the space defined by the first shell and the second shell, the first protective layer and the second protective layer are oppositely arranged;

A liquid lens disposed in a space defined by the first protective layer and the second protective layer.

Optionally, the first light source includes an infrared light source, and the second light source includes a white light source.

According to another aspect of the present invention, there is provided a focusing method for an auto-focus optical system, which is applied to the auto-focus optical system described in the first aspect of the present invention, including:

Obtain the detection image of the object to be detected based on the differential interference optical module;

determining defocus information of the image to be detected according to the detection image;

Determine adjustment information of the liquid focus module according to the defocus information and send the adjustment information to the driving module, so that the drive module adjusts the diopter of the liquid focus module according to the adjustment information.

In the technical solution of the embodiment of the present invention, by using the liquid lens to realize the zooming process of the optical system in the automatic focusing optical system, the diopter response time of the liquid lens is on the order of milliseconds, which greatly improves the focusing speed of the automatic focusing optical system, and The entire optical system has no mechanical movement during the focusing process, and the focal length is changed through the liquid lens, which eliminates the wear caused by mechanical movement, and the entire optical system is small in size, compact in structure, low in noise and good in stability.

It should be understood that the content described in this section is not intended to identify key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will be easily understood from the following description.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

FIG. 1 is a schematic block diagram of an autofocus optical system provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an autofocus optical system provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an imaging position adjustment unit in an autofocus optical system provided by an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a liquid focusing module provided by an embodiment of the present invention;

Fig. 5 is a structural schematic diagram of three diopter states of the liquid lens;

FIG. 6 is a flow chart of a focusing method for an auto-focusing optical system provided by an embodiment of the present invention.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

Fig. 1 is a schematic block diagram of an autofocus optical system provided by an embodiment of the present invention. As shown in Fig. 1, an autofocus optical system includes a differential interference optical module 10, a liquid focusing module 20, a processing module 30 and a driving Module 40; the differential interference optical module 10 is used to emit the detection beam to detect the object to be detected and obtain a detection image; the liquid focusing module 20 is arranged in the optical path of the differential interference optical module 10; the processing module 30 is connected with the differential interference optical module 10 and The drive module 40 is electrically connected, and is used to determine the defocus information of the image to be detected according to the detection image, determine the adjustment information of the liquid focus module 20 according to the defocus information, and send the adjustment information to the drive module 40; the drive module 40 is electrically connected to the liquid focus module 20 connected to adjust the diopter of the liquid focusing module 20 according to the adjustment information.

Wherein, the detection beam can be understood as a beam emitted by the differential interference optical module 10 to detect the object to be measured, for example, it can be an infrared beam or a beam of other wavelengths. The object to be detected can be understood as an object to be detected according to actual needs. Specifically, after the differential interference optical module 10 emits the detection beam to detect the object to be detected and acquires the detection image, the detection image information is transmitted to the processing module 30, and the processing module 30 determines the defocus information of the image to be detected according to the detection image, and the internal algorithm Convert the defocus information of the image to be detected into adjustment information, and send it to the drive module 40. After receiving the adjustment information, the drive module 40 adjusts the current or voltage at both ends of the liquid focusing module 20 according to the information, and then changes its curvature, thereby changing its diopter.

Since the liquid focusing module 20 is arranged in the optical path of the differential interference optical module 10, when the diopter of the liquid focusing module 20 changes, its adjustment effect on the detection image beam reflected by the object to be detected changes, so that the detection image beam can be further adjusted. The defocus information ensures that the detection image beam does not defocus, ensures that the detection image has good clarity and contrast, and realizes the accuracy of detection of the object to be detected.

It should be noted that the defocus information can be understood as a defocus amount and a defocus direction. The adjustment information can be understood as information on the magnitude of the adjustment current or voltage.

In the technical solution of the embodiment of the present invention, by using the liquid lens to realize the zooming process of the optical system in the automatic focusing optical system, the diopter response time of the liquid lens is on the order of milliseconds, which greatly improves the focusing speed of the automatic focusing optical system, and The entire optical system has no mechanical movement during the focusing process, and the focal length is changed through the liquid lens, which eliminates the wear caused by mechanical movement, and the entire optical system is small in size, compact in structure, low in noise and good in stability.

Fig. 2 is a schematic structural diagram of an autofocus optical system provided by an embodiment of the present invention, and Fig. 3 is a schematic structural diagram of an imaging position adjustment unit in an autofocus optical system provided by an embodiment of the present invention, shown in conjunction with Fig. 2 and Fig. 3 , the differential interference optical module 10 may include a light source unit 11, a polarizing unit 12, a differential interference unit 13, an objective lens unit 14, an eyepiece unit 15, a filter unit 16, an analyzer unit 17, an imaging position adjustment unit 18 and an imaging unit 19; The focusing module 20 is located in the optical path between the differential interference unit 13 and the eyepiece 151; the light source unit 11 includes a first light source 111 and a second light source 112, the first light source 111 is used to emit the first detection beam, and the second light source 112 is used to emit The second detection beam, the wavelength range of the first detection beam and the second detection beam is different; the polarizing unit 12 is respectively located on the propagation paths of the first detection beam and the second detection beam, and is used to modulate the first detection beam to form the first polarization the detection beam, modulating the second detection beam to form a second polarized detection beam; the differential interference unit 13 is respectively located on the propagation path of the first polarized detection beam and the second detection beam, and is used to modulate the first polarized detection beam to form a first differential polarization detection light beam, modulate the second polarized detection beam to form the second differential polarization detection beam; the objective lens unit 14 and the object to be detected are located in the transmission path of the first differential polarization detection beam and the second differential polarization detection beam in sequence, and the first differential polarization detection beam passes through After being reflected by the object to be detected, the first differentially polarized reflected beam is formed, and the first differentially polarized reflected beam is sequentially modulated by the objective lens and the differential interference unit to form the first imaging beam, and the first imaging beam carries the detection signal of the object to be detected; the second differentially polarized reflected beam The detection beam is reflected by the object to be detected to form a second differential polarized reflected beam, and the second differentially polarized reflected beam is sequentially modulated by the objective lens unit 14 and the differential interference unit 13 to form a second imaging beam, and the second imaging beam carries the detection Signal; the liquid focusing module 20 is respectively located on the propagation path of the first imaging beam and the second imaging beam, and is used to adjust the focal length of the first imaging beam and the second imaging beam; the filter unit 16 includes a first filter lens 161 and a second filter lens Lens 162, the filtering range of the first filter lens 161 and the second filter lens 162 are different; the analyzer unit 17 includes the first analyzer lens 171 and the second analyzer lens 172; the imaging unit 19 includes the first imaging unit 191 and the second Imaging unit 192: the first imaging light beam is imaged at the first position A and the second position B of the first imaging unit 191 after passing through the eyepiece unit 15, the first filter lens 161, the first analyzer lens 171, and the imaging position adjustment unit 18 in sequence , the first position A and the second position B are symmetrical to the image plane conjugated to the second imaging unit 192; Unit 192 imaging.

Wherein, the wavelength ranges of the first detection beam and the second detection beam are different, so that the detection images obtained by the first detection beam and the second detection beam can be respectively imaged in different imaging units, that is, the detection images obtained by one of the detection beams The image can be used as a comparison image of the detection image acquired by another detection beam, and the defocus information of the detection image is determined based on the comparison between the two detection images. Further, the first light source 111 and the second light source 112 can be arranged on the same side of the auto-focus optical system, or they can be respectively arranged on both sides of the auto-focus optical system, which is not limited in this embodiment of the present invention. FIG. 2 only The first light source 111 and the second light source 112 are set on the same side of the auto-focus optical system as an example for illustration.

Further, the first light source 111 includes an infrared light source, and the second light source 112 includes a white light source. In this way, on the one hand, it is ensured that the detection beams of different wavelengths can be imaged in different imaging units, which is convenient for distinguishing between the two imaging; on the other hand, the infrared light has a long wavelength and low energy, and the use of infrared light sources will not cause damage to optical devices. Ensure the normal operation of optical devices; at the same time, the white light source is a common light source in life, and the material is simple and economical. Exemplarily, when the first light source 111 is an infrared light source, the wavelength range of the first probe beam emitted by it is 0.75 μm-1000 μm; when the second light source 112 is a white light source, the wavelength range of the second probe beam emitted by it is 390 nm- 780nm. The wavelength ranges of the first detection beam and the second detection beam are different, so that they can be detected separately.

Wherein, the polarizing unit 12 can be understood as a device for modulating the light beam of the light source into a polarized beam, for example, it can be a polarization beam splitter. Specifically, the polarizing units 12 are respectively located on the propagation paths of the first detection beam and the second detection beam, and are used to modulate the first detection beam to form a first polarized detection beam, and modulate the second detection beam to form a second polarized detection beam, so as to facilitate Subsequently, the object to be detected is detected with a polarized beam.

Corresponding to the polarizing unit 12, the differential interference optical module in the embodiment of the present invention may also include a polarizing unit 17, which may also be a polarization beam splitter for transmitting the polarization of the polarizing unit 17. Light rays with the same axial polarization. Corresponding to different wavelengths of the detection beams, as shown in FIG. 2 , the analyzer unit 17 may specifically include a first analyzer lens 171 and a second analyzer lens 172 , which respectively perform analysis and adjustment on the probe beams with different wavelengths.

Further, the differential interference optical module 11 provided by the embodiment of the present invention may also include a differential interference unit 13, an objective lens unit 14, an eyepiece unit 15, a filter unit 16, an analyzer unit 17, an imaging position adjustment unit 18, and an imaging unit 19. A light source 111 emits a first detection beam, passes through a polarizing unit 12 located on its propagation path, and forms a first polarized detection beam after modulation. The first polarized detection beam propagates along the optical path, and after passing through a differential interference unit 13, it is modulated into The first differentially polarized detection beam, the first differentially polarized detection beam is two beams of linearly polarized light with a small angle, the vibration direction is perpendicular to each other, and the amplitude is equal, the first differentially polarized detection beam propagates along the optical path, and is incident on the surface of the object to be detected , after being reflected by the object to be detected, the first differential polarized reflected beam is formed, continues to propagate along the optical path, and is sequentially modulated by the objective lens 14 and the differential interference unit 13 to form the first imaging beam carrying the image information of the object to be detected; in the first light source 111 Simultaneously with emitting the first detection beam, the second light source 112 emits the second detection beam, which is modulated by the same steps to form a second imaging beam carrying image information of the object to be detected. The first imaging beam propagates along the optical path, passes through the eyepiece unit 15, the first filter lens 161, the first analyzer lens 171, the imaging position adjustment unit 18, and then projects to the first position A and the second position of the first imaging unit 191. Imaging at position B; the second imaging light is formed in the second imaging unit 192 after passing through the eyepiece 15 , the second filter lens 162 and the second analyzer lens 172 in sequence. Such imaging light beams with different wavelengths can be imaged in different imaging units respectively.

Further, the liquid focusing module 20 is located in the optical path between the differential interference unit 13 and the eyepiece 151, so that the liquid focusing module 20 can adjust the focal length information of the imaging beam before entering the eyepiece, so as to ensure that the imaging unit can obtain a clear detection image, which is convenient for realizing the treatment Accurate detection of detection objects.

Further, the imaging unit 19 can be understood as an electronic device configured in the differential interference optical module 10 and capable of imaging, for example, it can be a CCD system or a CMOS system.

Optionally, the differential interference optical module 10 further includes a mask pattern unit 103 .

The mask pattern unit 103 is located on the propagation path of the first detection beam, and is used for modulating the first detection beam to form a pattern detection beam.

Among them, the mask pattern unit 103 can be understood as an optical device that can change the image shape information carried by the light beam. By adding a mask pattern unit on the propagation path of the first detection beam, the first detection beam and the first imaging beam are both Carrying a mask pattern, the detection images formed at the first position A and the second position B also carry a mask pattern, which facilitates the comparison between the detection image formed at the first position A and the detection image formed at the second position B , to ensure that the detection images at different positions can be compared simply and clearly, and the contrast difference can be accurately obtained for accurate adjustment of the diopter of the liquid focusing module to ensure the subsequent accurate detection of the object to be detected.

Optionally, the mask pattern unit includes a grating component.

Exemplarily, when the mask pattern unit is a one-dimensional grating component, since the grating is equidistant parallel slits, different brightness levels between the brightest white and the darkest black in the bright and dark areas of the image can be observed more clearly, and then It can be more intuitive to compare whether there is a difference in the contrast of the two images of AB.

Optionally, as shown in FIG. 3 , the imaging position adjustment unit 18 includes a first lens sheet 181 and a first reflective sheet 182; the first imaging light beam is transmitted to the first position A after being transmitted by the first lens sheet 181, After being reflected by the first reflective sheet 181 , it is reflected by the first reflective sheet and enters the second position B.

Specifically, the first imaging light beam is divided into two after passing through the first reflective sheet 181, half of the light is directly irradiated on the first position A of the first imaging unit 191, and the other half of the light is reflected by the first reflective sheet 181 and the first After being reflected by the lens 182, it is irradiated at the second position B of the first imaging unit 191, so that the first imaging light beam can be imaged at both the first position A and the second position B. Since the first position A and the second position B are symmetrical to the image plane conjugate to the second imaging unit 192, the differential interference can be determined by comparing the detection image at the first position A with the detection image at the second position B Defocus information sent by the optical module 11.

Optionally, as shown in FIG. 2 , the differential interference optical module 10 further includes a second lens reflection sheet 101 and a third lens reflection sheet 102; the second lens reflection sheet 101 is located between the polarizer unit 12 and the differential interference interference unit 13 In the optical path of the differential interference unit 13 and the optical path between the liquid focusing module 20, it is used to reflect the first polarized detection beam and the second polarized detection beam to the differential interference unit 13, and transmit the first imaging beam and the second imaging beam to the differential interference unit 13. Liquid focus module 20;

The third lens mirror 102 is located in the optical path between the eyepiece unit 15 and the filter unit 16, and is used to reflect the first imaging beam and the second imaging beam to the first filter lens 161, and transmit the first imaging beam and the second imaging beam to the filter lens 161. The second filter lens 162 .

Specifically, the first polarized detection beam modulated by the polarizing unit propagates along the optical path, and the second lens sheet 101 located in its propagation path reflects half of the light downwards to the differential interference unit 13, where it is modulated into the first differential polarization detection beam. Beam, the first differentially polarized detection beam is two beams of linearly polarized light with a small angle, perpendicular to each other, and equal amplitude, the first differentially polarized detection beam propagates along the optical path, enters the surface of the object to be detected, and passes through the object to be detected After reflection, the first differentially polarized reflected beam is formed, continues to propagate along the optical path, and after passing through the objective lens 14 and the differential interference unit 13 in turn, the two beams in the first differentially polarized detection beam have a small angle and the vibration direction is perpendicular to each other, and the amplitude is equal to linear polarization Optically synthesize a beam of light to form the first imaging beam carrying the image information of the object to be detected. The first imaging beam propagates through the focusing module 20 and the eyepiece unit 15 in turn, and then propagates to the third mirror lens 102, which is divided into two, half transmitted to the first filter lens 161 and the other half to the second filter lens 162 . At the same time, the second polarized detection beam also propagates to the first filter lens 161 and the second filter lens 162 through the same steps as above. By arranging the second reflective sheet and the third reflective sheet, the normal propagation of the detection light beam and the imaging light beam is ensured, and the detection image of the object to be detected can be obtained.

Optionally, continuing to refer to FIG. 2 , the differential interference optical module 10 further includes a second reflective sheet 104 and a fourth lens reflective sheet 105;

The second reflective sheet 104 is located in the optical path between the first light source 111 and the fourth reflective sheet 105, for reflecting the first detection beam to the fourth reflective sheet 105;

The fourth transflective sheet 105 is located in the optical path between the second reflective sheet 104 and the polarizing unit 12 and in the optical path between the second light source 112 and the polarizing unit 12, for transmitting the first detection beam to the polarizing unit 12, reflecting The second detection beam is sent to the polarizing unit 12 .

Specifically, the first light source 111 emits the first detection beam, the beam passes through the second reflective sheet 104, is reflected to the fourth reflective sheet 105, and reaches the polarizing unit 12 after passing through the fourth reflective sheet 105; the second light source 112 emits a second detection beam, which propagates along the optical path and passes through the fourth lens sheet 105 on its propagation path, and is reflected to the polarizing unit 12 . Through the arrangement of the second reflective sheet 104 and the fourth reflective sheet 105, the propagation direction of the optical path in the system is changed, so that the arrangement of various components in the whole system is more concentrated, and the volume of the system equipment is reduced.

On the basis of the above-mentioned embodiments, FIG. 4 is a schematic structural diagram of a liquid focusing module provided by an embodiment of the present invention. As shown in FIG. 4 , the liquid focusing module 20 may include a first housing 201 and a second housing 202 disposed opposite to each other. The first protective layer 203 and the second protective layer 204 arranged in the space defined by the first shell 201 and the second shell 202, the first protective layer 203 and the second protective layer 204 are arranged oppositely; The second protective layer 204 defines a liquid lens 205 within the space.

Wherein, the first protection layer 203 and the second protection layer 204 can be understood as optical devices with light transmission, for example, they can be flat light transmission glass.

Specifically, FIG. 5 is a schematic structural diagram of three diopter states of the liquid lens 205. As shown in FIG. Water-based, which makes the film deform, thereby adjusting the curvature of the liquid lens 205, and then changing its diopter, and finally achieves the purpose of adjusting the focal length of the lens, so as to cooperate with the objective lens group and the eyepiece group to achieve clear imaging with different depths of field. In addition, due to the short response time of the liquid lens module (about 25ms), it can achieve fast focusing.

Based on the same inventive concept, an embodiment of the present invention also provides a focusing method for an automatic focusing optical system. Specifically, FIG. 6 shows a focusing method for an automatic focusing optical system provided by an embodiment of the present invention A flow chart of the method, the method is realized based on the aforementioned automatic focusing optical system, as shown in Figure 6, the method includes the following steps:

S110. Acquire a detection image of the object to be detected based on the differential interference optical module.

Specifically, in combination with the autofocus optical system in FIG. 2 and FIG. 3 , the acquisition process of the detection image will be described. The first light source 111 emits the first detection beam, which enters the mask pattern unit 103 located on its optical path, and is modulated according to the mask pattern in the unit to form a pattern. The detection beam continues to propagate, and is reflected by the second reflector 104 along the optical path. Continue to propagate, pass through the fourth lens sheet 105, enter the polarizing unit 12 on its propagation path, form the first polarized detection beam after modulation, the first polarized detection beam propagates along the optical path, and the second lens sheet 101 Reflect half of the light downwards to the differential interference unit 13, and modulate it into the first differential polarization detection beam. The first differential polarization detection beam is two beams of linearly polarized light with a small angle, perpendicular to each other, and equal in amplitude. The first The differentially polarized detection beam propagates along the optical path, enters the surface of the object to be detected through the objective lens 14, forms the first differentially polarized reflected light beam after being reflected by the object to be detected, continues to propagate along the optical path, and passes through the objective lens 14 and the differential interference unit 13 in turn. In a differentially polarized detection beam, two beams have a small angle and the vibration directions are perpendicular to each other, and the linearly polarized lights with equal amplitudes are synthesized into a beam of light to form a first imaging beam carrying image information of the object to be detected. The first imaging light beam successively passes through the second transflective sheet 101, the liquid focusing module 20, and the eyepiece 15, and then half of the light is reflected by the third transflective sheet 102 to the first filter lens 161 and the first analyzer lens 171, and is then captured by the first The transflective sheet 181 divides the light into two, half of the light is directly irradiated on the first position A of the first imaging unit 191, and the other half of the light is reflected 182 by the first transflective sheet 181 and the first reflective sheet, and irradiates on the first position A of the first imaging unit 191. The second position B of the imaging unit 191 , at this time, the first imaging unit acquires images of two points A and B. While the first light source 111 emits the first detection beam, the second light source 112 emits a second detection beam with a wavelength range different from that of the first detection beam, which is reflected by the second reflector 105 and continues to propagate along the optical path, and is incident on the The polarizing unit 12 on the path forms a second polarized detection beam after modulation, and the second polarized detection beam propagates along the optical path, and the second lens mirror 101 reflects half of the light downward to the differential interference unit 13, and is modulated into a second polarized detection beam. Differentially polarized detection beams, the second differentially polarized detection beams are two beams of linearly polarized light with a small angle, perpendicular to each other, and equal amplitudes, the second differentially polarized detection beams propagate along the optical path, and enter the object to be detected through the objective lens 14 The surface, after being reflected by the object to be detected, forms the second differentially polarized reflected beam, which continues to propagate along the optical path, and after being modulated by the objective lens 14 and the differential interference unit 13 in turn, the two beams in the second differentially polarized detection beam have a small angle and the vibration directions are mutually Vertical, linearly polarized lights with equal amplitudes are synthesized into one beam to form a second imaging beam carrying image information of the object to be detected. The second imaging light beam successively passes through the second transflective sheet 101, the liquid focusing module 20, and the eyepiece 15, and then half of the light is reflected by the third transflective sheet 102 to be blocked by the first filter lens, and the other half of the light is directly transmitted through the third transflective sheet 102 , passes through the second filter lens 162 and the second analyzer lens 172 successively, and is finally projected on the second imaging unit 191 .

S120. Determine defocus information of the image to be detected according to the detection image.

Specifically, after acquiring the detection image of the object to be detected, at this time, both points A and B on the first imaging unit have detection images of the object to be detected, and the processing module compares the difference in the contrast value of the detection image at positions A and B , and then obtain information such as defocus amount and defocus direction.

S130. Determine adjustment information of the liquid focus module according to the defocus information and send the adjustment information to the driving module, so that the drive module adjusts the diopter of the liquid focus module according to the adjustment information.

Specifically, after determining the defocus amount and defocus direction and other information, the processing module converts the defocus information into adjustment information of the liquid focus module through an internal algorithm, and sends the adjustment information to the drive module, and the drive module further adjusts the focus according to the adjustment information. The magnitude of the voltage/current value at both ends of the liquid focusing module can then adjust the curvature of the liquid lens, thereby adjusting the diopter of the liquid focusing module.

Exemplarily, after determining the defocus amount and defocus direction and other information, the processing module can select the driving voltage/current that matches the defocus information as the target voltage/current according to the defocus information, and control the driving module to send Output the target voltage/current to change the hydrophilicity of the oil-water intersecting film in the liquid lens, causing the film to deform, thereby adjusting the curvature of the liquid lens, thereby changing its diopter, and finally achieving the purpose of adjusting the focal length of the lens.

In the technical solution of the embodiment of the present invention, by using the liquid lens to realize the zooming process of the optical system in the automatic focusing optical system, the diopter response time of the liquid lens is on the order of milliseconds, which greatly improves the focusing speed of the automatic focusing optical system, and The entire optical system has no mechanical movement during the focusing process, and the focal length is changed through the liquid lens, which eliminates the wear caused by mechanical movement, and the entire optical system is small in size, compact in structure, low in noise and good in stability.

It should be understood that steps may be reordered, added or deleted using the various forms of flow shown above. For example, each step described in the present invention may be executed in parallel, sequentially, or in a different order, as long as the desired result of the technical solution of the present invention can be achieved, there is no limitation herein.

The above specific implementation methods do not constitute a limitation to the protection scope of the present invention. It should be apparent to those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made depending on design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. An automatic focusing optical system is characterized by comprising a differential interference optical module, a liquid focusing module, a processing module and a driving module;

the differential interference optical module is used for emitting a detection beam to detect an object to be detected and acquiring a detection image;

the liquid focusing module is arranged in the light path of the differential interference optical module;

the processing module is respectively electrically connected with the differential interference optical module and the driving module and is used for determining out-of-focus information of the image to be detected according to the detected image, determining adjustment information of the liquid state focusing module according to the out-of-focus information and sending the adjustment information to the driving module;

the driving module is electrically connected with the liquid focusing module and used for adjusting the diopter of the liquid focusing module according to the adjusting information.

2. The auto-focus optical system according to claim 1, wherein the differential interference optical module includes a light source unit, a polarizing unit, a differential interference unit, an objective lens unit, an eyepiece lens unit, a filter unit, an analyzing unit, an imaging position adjusting unit, and an imaging unit;

the liquid focusing module is positioned in a light path between the differential interference unit and the eyepiece;

the light source unit comprises a first light source and a second light source, the first light source is used for emitting a first detection light beam, the second light source is used for emitting a second detection light beam, and the wavelength ranges of the first detection light beam and the second detection light beam are different;

the polarization unit is respectively positioned on the propagation paths of the first detection beam and the second detection beam and is used for modulating the first detection beam to form a first polarized detection beam and modulating the second detection beam to form a second polarized detection beam;

the differential interference unit is respectively positioned on the propagation paths of the first polarized detection beam and the second polarized detection beam and is used for modulating the first polarized detection beam to form a first differential polarized detection beam and modulating the second polarized detection beam to form a second differential polarized detection beam;

the objective lens unit and the object to be detected are sequentially located on a transmission path of the first differential polarization detection beam and the second differential polarization detection beam, the first differential polarization detection beam is reflected by the object to be detected to form a first differential polarization reflected beam, the first differential polarization reflected beam is modulated by the objective lens and the differential interference unit in sequence to form a first imaging beam, and the first imaging beam carries a detection signal of the object to be detected; the second differential polarization detection beam is reflected by the object to be detected to form a second differential polarization reflected beam, the second differential polarization reflected beam is modulated by the objective lens unit and the differential interference unit in sequence to form a second imaging beam, and the second imaging beam carries a detection signal of the object to be detected;

the liquid focusing module is respectively positioned on the propagation paths of the first imaging light beam and the second imaging light beam and is used for adjusting the focal lengths of the first imaging light beam and the second imaging light beam;

the filtering unit comprises a first filtering lens and a second filtering lens, and the filtering ranges of the first filtering lens and the second filtering lens are different; the polarization analyzing unit comprises a first polarization analyzing lens and a second polarization analyzing lens; the imaging unit includes a first imaging unit and a second imaging unit; the first imaging light beam sequentially passes through the eyepiece unit, the first filter lens, the first polarization analyzing lens and the imaging position adjusting unit and then is imaged at a first position and a second position of the first imaging unit, and the first position and the second position are symmetrical to an imaging plane conjugated with the second imaging unit; and the second imaging light beam sequentially passes through the ocular lens, the second filter lens and the second polarization analyzing lens and then is imaged in the second imaging unit.

3. The auto-focus optical system according to claim 2, wherein the differential interference optical module further includes a mask pattern unit;

the mask pattern unit is located on a propagation path of the first probe beam for modulating the first probe beam to form a patterned probe beam.

4. The autofocus optical system of claim 3, wherein the mask pattern unit comprises a grating assembly.

5. The autofocus optical system of claim 2, wherein the imaging position adjusting unit includes a first transflective lens and a first reflective lens;

the first imaging light beam is transmitted by the first transflective lens and then is incident to the first position, and the first imaging light beam is reflected by the first transflective lens and then is incident to the second position after being reflected by the first reflector.

6. The autofocus optical system of claim 2, wherein the differential interference optical module further comprises a second transflective lens and a third transflective lens;

the second transflective lens is positioned in a light path between the polarizing unit and the differential interference unit and a light path between the differential interference unit and the liquid state focusing module, and is used for reflecting the first polarized detection light beam and the second polarized detection light beam to the differential interference unit and transmitting the first imaging light beam and the second imaging light beam to the liquid state focusing module;

the third transflective lens is positioned in a light path between the ocular unit and the filter unit, and is used for reflecting the first imaging light beam and the second imaging light beam to the first filter lens and transmitting the first imaging light beam and the second imaging light beam to the second filter lens.

7. The autofocus optical system of claim 2, wherein the differential interference optical module further comprises a second mirror and a fourth transflective mirror;

the second reflecting lens is positioned in an optical path between the first light source and the fourth transflective lens and is used for reflecting the first detection light beam to the fourth transflective lens;

the fourth transflective lens is positioned in a light path between the second reflector and the polarizing unit and a light path between the second light source and the polarizing unit, and is used for transmitting the first detection light beam to the polarizing unit and reflecting the second detection light beam to the polarizing unit.

8. The autofocus optical system of claim 1, wherein the liquid focus module comprises first and second oppositely disposed housings;

a first protective layer and a second protective layer disposed within a space defined by the first housing and the second housing, the first protective layer and the second protective layer being disposed opposite to each other;

and the liquid lens is arranged in a space defined by the first protective layer and the second protective layer.

9. The autofocus optical system of claim 2, wherein the first light source comprises an infrared light source and the second light source comprises a white light source.

10. A focusing method of an automatic focusing optical system applied to the automatic focusing optical system according to any one of claims 1 to 9, comprising:

acquiring a detection image of an object to be detected based on a differential interference optical module;

determining out-of-focus information of the image to be detected according to the detection image;

and determining the adjustment information of a liquid focusing module according to the defocusing information and sending the adjustment information to the driving module so that the driving module adjusts the diopter of the liquid focusing module according to the adjustment information.

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