阅读说明：本技术 自动对焦系统 (Automatic focusing system ) 是由 樊思民 于 2021-07-06 设计创作，主要内容包括：本发明公开一种自动对焦系统,所述自动对焦系统包括多个第一光源、多个透镜、物镜、第一相机以及处理器；所述物镜的光轴位于多个所述第一光源的内侧,多个所述第一光源用于分别发出各自对应的特征信号光束,每一所述第一光源所发出的特征信号光束经过一所述透镜而形成平行光并射向所述物镜,多个所述第一光源的特征信号光束经过所述物镜后在物面分别形成特征图像,所述第一相机用于捕获形成于所述物面的多个特征图像,所述处理器用于根据不同的特征图像的相对位置以确定所述自动对焦系统的离焦方向和离焦量,并根据所述离焦方向和离焦量确定所述物镜位置的调整量。本发明技术方案实现自动对焦迅速,准确。(The invention discloses an automatic focusing system, which comprises a plurality of first light sources, a plurality of lenses, an objective lens, a first camera and a processor, wherein the first light sources are arranged on the first side of the lens; the optical axis of the objective lens is located at the inner side of the first light sources, the first light sources are used for respectively emitting corresponding characteristic signal beams, the characteristic signal beam emitted by each first light source passes through the lens to form parallel light and emits towards the objective lens, the characteristic signal beams of the first light sources pass through the objective lens to respectively form characteristic images on an object plane, the first camera is used for capturing the characteristic images formed on the object plane, and the processor is used for determining the defocusing direction and the defocusing amount of the automatic focusing system according to the relative positions of different characteristic images and determining the adjustment amount of the position of the objective lens according to the defocusing direction and the defocusing amount. The technical scheme of the invention realizes rapid and accurate automatic focusing.)

1. An auto-focus system, comprising a plurality of first light sources, a plurality of lenses, an objective lens, a first camera, and a processor;

the optical axis of the objective lens is located at the inner side of the first light sources, the first light sources are used for respectively emitting corresponding characteristic signal beams, the characteristic signal beam emitted by each first light source passes through the lens to form parallel light and emits towards the objective lens, the characteristic signal beams of the first light sources pass through the objective lens to respectively form characteristic images on an object plane, the first camera is used for capturing the characteristic images formed on the object plane, and the processor is used for determining the defocusing direction and the defocusing amount of the automatic focusing system according to the relative positions of different characteristic images and determining the adjustment amount of the position of the objective lens according to the defocusing direction and the defocusing amount.

2. The autofocus system of claim 1, further comprising a first beam splitter, a dichroic mirror, and a first tube mirror;

the characteristic signal light beam emitted by the lens is emitted to the dichroic mirror through the light splitting action of the first dichroic mirror, the dichroic mirror reflects the characteristic signal light beam to the lens and then reaches the object plane, and the object plane enables the characteristic signal light beam to sequentially pass through the lens, the dichroic mirror, the first dichroic mirror and the first tube mirror and then enter the first camera to form a characteristic image.

3. The autofocus system of claim 2, further comprising a light focusing assembly positioned between the lens and the first beam splitter, the light focusing assembly configured to focus the characteristic signal beam emitted by the lens onto the first beam splitter.

4. The auto-focusing system of claim 3, wherein the light-focusing assembly comprises a plurality of second beam splitters and a plurality of light-focusing prisms, a light-exiting surface of each lens is provided with one second beam splitter, a light-focusing prism is arranged between two adjacent second beam splitters, and the characteristic signal beam emitted from the lens is reflected by the second beam splitters and the light-focusing prisms twice and then emitted to the first beam splitter;

or, the light-gathering component comprises a third spectroscope and a fourth optical device which are respectively arranged corresponding to the two adjacent lenses, the characteristic signal light beam emitted by one of the two adjacent lenses is reflected to the fourth optical device through the third spectroscope and then emitted to the first spectroscope after being reflected by the fourth optical device, and the characteristic signal light beam emitted by the other of the two adjacent lenses is emitted to the first spectroscope after passing through the fourth optical device.

5. The autofocus system of claim 4, wherein the fourth optical device is a beam splitter having a splitting ratio of 50/50, a polarizing beam splitter, or a dichroic mirror.

6. The autofocus system of claim 1, wherein the autofocus system further comprises an adjuster;

the processor generates an adjusting command according to the adjusting quantity and sends the adjusting command to the adjuster;

the adjuster adjusts the position of the objective lens according to the adjustment command.

7. The autofocus system of claim 1, wherein the first light source comprises a laser source body and a reticle.

8. The autofocus system of claim 1, wherein the first light source is a display screen capable of receiving digital signals.

9. The autofocus system of claim 1, further comprising a second light source, a fourth beam splitter, a second tube mirror, and a second camera;

the illumination light emitted by the second light source is reflected to the dichroic mirror through the fourth light splitting mirror, the dichroic mirror performs light splitting processing on the illumination light and emits the illumination light to the objective lens, the illumination light passing through the objective lens is projected to the object plane and used for illuminating an object to be detected on the object plane, the object to be detected reflects the illumination light to form reflection light, and the reflection light sequentially passes through the objective lens, the dichroic mirror, the fourth light splitting mirror and the second tube mirror and finally converges to the second camera.

10. The autofocus system of claim 9, wherein the fourth beamsplitter has a split ratio of 50/50.

Technical Field

The invention relates to the technical field of optics, in particular to an automatic focusing system.

Background

Autofocus techniques are broadly divided into two categories: the first type directly calculates the image contrast of the imaged object and searches the lens position with the highest contrast; the second category requires special auto-focus systems. The first type requires that the focusing moving direction is judged in advance, which does not meet the requirements of modern industry on efficiency, so the second focusing mode is generally adopted.

The existing automatic focusing mode makes judgment through different spot shapes of semi-conical light beams before and after focusing on a focusing surface. When the laser is focused outside the focal point (before the focal point), the laser spot presents a left semicircular shape; when the laser is focused in the focus (after the focus), the laser spot is in a right semicircular shape; at the focal point, the laser beam theoretically converges to a point. Theoretically, in the process of gradually defocusing the lens from the focal position in actual operation, the shape change of the laser beam is slow, and the numerical aperture of the beam in the shape of the hemipyramid only occupies half of the numerical aperture of the microscope, that is, the focal depth of the focusing signal is greater than that of the objective lens, so that the degree of defocusing of the object cannot be sufficiently reflected.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention mainly aims to provide an automatic focusing system, and aims to solve the technical problem of inaccurate focusing imaging in the prior art.

In order to achieve the above object, the present invention provides an auto-focusing system, which includes a plurality of first light sources, a plurality of lenses, an objective lens, a first camera, and a processor;

the optical axis of the objective lens is located at the inner side of the first light sources, the first light sources are used for respectively emitting corresponding characteristic signal beams, the characteristic signal beam emitted by each first light source passes through the lens to form parallel light and emits towards the objective lens, the characteristic signal beams of the first light sources pass through the objective lens to respectively form characteristic images on an object plane, the first camera is used for capturing the characteristic images formed on the object plane, and the processor is used for determining the defocusing direction and the defocusing amount of the automatic focusing system according to the relative positions of different characteristic images and determining the adjustment amount of the position of the objective lens according to the defocusing direction and the defocusing amount.

The automatic focusing system provided by the technical scheme of the invention has the advantages that the defocusing direction and the defocusing amount are more easily obtained through comparing the relative positions of different characteristic images compared with the conventional focusing mode in which the semi-cone beam is focused on the focusing surface in different spot shapes before and after the focusing through the relative position comparison among different characteristic images, and the focusing mode cannot be influenced by the objective factor that the numerical aperture of the semi-cone beam only occupies half of the numerical aperture of a microscope, so that the in-focus imaging is more accurate.

Optionally, the auto-focusing system further comprises a first beam splitter, a dichroic mirror, and a first tube mirror;

the characteristic signal light beam emitted by the lens is emitted to the dichroic mirror through the light splitting action of the first dichroic mirror, the dichroic mirror reflects the characteristic signal light beam to the lens and then reaches the object plane, and the object plane enables the characteristic signal light beam to sequentially pass through the lens, the dichroic mirror, the first dichroic mirror and the first tube mirror and then enter the first camera to form a characteristic image.

Optionally, the auto-focusing system further includes a light-focusing assembly, the light-focusing assembly is located between the lens and the first beam splitter, and the light-focusing assembly is configured to converge the characteristic signal light beam emitted by the lens to the first beam splitter.

Optionally, the light condensing assembly includes a plurality of second beam splitters and a plurality of light condensing prisms, a light exit surface of each lens is provided with one second beam splitter correspondingly, a light condensing prism is arranged between two adjacent second beam splitters, and the characteristic signal light beam emitted by the lens is reflected to the first beam splitter after being reflected by the second beam splitters and the light condensing prisms twice;

or, the light-gathering component comprises a third spectroscope and a fourth optical device which are respectively arranged corresponding to the two adjacent lenses, the characteristic signal light beam emitted by one of the two adjacent lenses is reflected to the fourth optical device through the third spectroscope and then emitted to the first spectroscope after being reflected by the fourth optical device, and the characteristic signal light beam emitted by the other of the two adjacent lenses is emitted to the first spectroscope after passing through the fourth optical device.

Optionally, the fourth optical device is a beam splitter with a splitting ratio of 50/50, a polarizing beam splitter, or a dichroic mirror.

Optionally, the autofocus system further comprises an adjuster;

the processor generates an adjusting command according to the adjusting quantity and sends the adjusting command to the adjuster;

the adjuster adjusts the position of the objective lens according to the adjustment command.

Optionally, the first light source includes a laser source body and a reticle.

Optionally, the first light source is a display screen capable of receiving digital signals.

Optionally, the auto-focusing system further comprises a second light source, a fourth spectroscope, a second tube lens, and a second camera;

the illumination light emitted by the second light source is reflected to the dichroic mirror through the fourth light splitting mirror, the dichroic mirror performs light splitting processing on the illumination light and emits the illumination light to the objective lens, the illumination light passing through the objective lens is projected to the object plane and used for illuminating an object to be detected on the object plane, the object to be detected reflects the illumination light to form reflection light, and the reflection light sequentially passes through the objective lens, the dichroic mirror, the fourth light splitting mirror and the second tube mirror and finally converges to the second camera.

Optionally, the fourth dichroic mirror has a splitting ratio of 50/50.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic diagram of an auto-focusing system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an auto-focusing system according to another embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an auto-focusing system according to yet another embodiment of the present invention;

FIG. 4 is a schematic diagram of an application scenario of the auto-focusing system of FIG. 1;

FIG. 5 is a schematic diagram of another application scenario of the auto-focusing system of FIG. 1;

FIG. 6 is a schematic view of another application scenario of the auto-focusing system of FIG. 1;

FIG. 7 is a schematic diagram illustrating the defocus calculation of the auto-focusing system of FIG. 1;

fig. 8 is another schematic diagram of fig. 7.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				10a、10b	First light source	C3	Third divisionLight mirror
20a、20b	Lens and lens assembly	C4	Fourth optical device
				30	Objective lens	70	First tube mirror
40	First camera	80	Second light source
				50	First beam splitter	90	Fourth spectroscope
60	Dichroic mirror	110	Second tube mirror
				C	Light gathering assembly	120	Second camera
C1	Second beam splitter	W	Article surface

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, "and/or" in the whole text includes three schemes, taking a and/or B as an example, including a technical scheme, and a technical scheme that a and B meet simultaneously; in addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The invention provides an automatic focusing system.

Referring to fig. 1 to 4, in an embodiment of the present invention, an auto-focusing system includes a plurality of first light sources (10a, 10b), a plurality of lenses (20a, 20b), an objective lens 30, a first camera 40, and a processor (not shown).

The optical axis of the objective lens 30 is located inside a plurality of first light sources (10a, 10b), the plurality of first light sources (10a, 10b) are used for respectively emitting corresponding characteristic signal beams, the characteristic signal beams emitted by each first light source (10a, 10b) pass through a lens (20a, 20b) to form parallel light and emit the parallel light to the objective lens 30, the characteristic signal beams of the plurality of first light sources (10a, 10b) pass through the objective lens 30 to respectively form characteristic images on the object plane W, the first camera 40 is used for capturing the plurality of characteristic images formed on the object plane W, and the processor is used for determining the defocusing direction and the defocusing amount of the automatic focusing system according to the relative positions of different characteristic images and determining the adjustment amount of the position of the objective lens 30 according to the defocusing direction and the defocusing amount.

The first light source (10a, 10b) can be a laser source body and a mask plate, and the pattern of the mask plate is projected onto the measured object surface W through the laser source body to form a characteristic image. The first light sources (10a, 10b) can also be display screens capable of receiving digital signals, such as LCDs, DLPs, LCoS microdisplays and the like, and feature images are directly displayed through the screens for focusing. The application is not limited to the choice of the first light sources (10a, 10b), and other schemes for generating the characteristic image are also applicable. The number of the lenses (20a, 20b) corresponds to the number of the first light sources (10a, 10b), the lenses (20a, 20b) may be convex lenses (20a, 20b), and for example, a cylindrical mirror may be used, wherein the first light sources (10a, 10b) of the present application are located on the focal planes of the lenses (20a, 20b) and are located at the sides of the optical axis of the objective lens 30, wherein the plurality of first light sources (10a, 10b) may be symmetrically arranged with respect to the optical axis of the objective lens 30 or asymmetrically arranged, which is not limited in the present application.

The automatic focusing system provided by the technical scheme of the invention has the advantages that the automatic focusing system can easily obtain the defocusing direction and the defocusing amount by comparing the relative positions of different characteristic images compared with the conventional focusing mode in which the judgment is made by different spot shapes of a semi-conical light beam on a focusing surface before focusing due to the fact that the relative position comparison is carried out among different characteristic images by arranging the plurality of first light sources (10a and 10b), each first light source (10a and 10b) can emit the corresponding characteristic signal light beam, the characteristic signal light beams of the plurality of first light sources (10a and 10b) form characteristic images on the object surface W after passing through the objective lens 30, the processor captures the plurality of characteristic images, the defocusing direction and the defocusing amount are judged by comparing the relative positions of different characteristic images, and the adjustment amount of the position of the objective lens 30 is determined according to the defocusing direction and the defocusing amount, the method is not influenced by the objective factor that the numerical aperture of the light beam in the shape of the half cone only accounts for half of the numerical aperture of the microscope, so that the focusing imaging is more accurate.

The following description will be further made with respect to the present invention, in which two first light sources (10a, 10b) are provided, that is, the first light source 10a and the first light source 10b, and two corresponding lenses (20a, 20b) are provided, that is, the lens 20a and the lens 20b, respectively.

For the present application, the defocus direction and defocus amount are determined by comparing the relative positions of different characteristic images, specifically, referring to fig. 4 to 6, in the example of fig. 4, the characteristic image displayed by the characteristic signal beam emitted by the first light source 10a is a single line (the single line is thicker in the figure for easy distinction), and the characteristic image displayed by the characteristic signal beam emitted by the first light source 10b is a double line, and by setting the image size, the single line can be located at the inner side of the double line, as can be shown by the content of fig. 4, since the light rays of the first light source 10a and the first light source 10b intersect at the focal plane of the objective lens 30, when the object plane W is exactly at the focal plane, the displayed characteristic image is that the single line is exactly at the middle position of the double line, since the emergent light rays from the light emergent surface of the objective lens 30 gradually converge to the focal plane of the objective lens 30 in a cone shape, therefore, when the object plane W is in focus, the single line is shifted to the right, and the distance between the single line and the left line in the double line is increased and the distance between the single line and the right line is decreased because the single line is closer to the right line in the double line, so that when the first camera 40 captures the image, the object plane W can be very quickly and accurately identified to be in focus through the preset judgment rule. Similarly, since the emergent light from the light-emitting surface of the objective lens 30 is also diverged in a cone shape after passing through the focal plane, when the object plane W is out of focus, the single line is deviated to the left side, and is closer to the left line of the double line, so that the distance between the single line and the left line of the double line is reduced and the distance between the single line and the right line is increased, and thus the processor can quickly and accurately judge that the object plane W is out of focus through the characteristic image captured by the first camera 40. Fig. 5 and 6 show the characteristic images formed by the first light source 10a and the first light source 10b as circles and triangles, respectively, and it can be understood that, referring to the principle description of the previous embodiment, when the object plane W is in the focal plane of the objective lens 30, respectively, show a pattern of concentric circles and symmetrically arranged triangles with vertices touching, when the object plane W is in the focus of the objective lens 30, respectively, showing a pattern in which the inner circle is shifted to the left and the two triangles are distant from each other, when the object plane W is out of focus of the objective lens 30, the patterns with the inner circle shifted to the right and the two triangular parts overlapped are respectively displayed, and by the above way, the processor can very accurately and rapidly identify the defocusing direction of the object plane W through the relative position relation of the characteristic images formed by the different first light sources (10a, 10b) captured by the first camera 40.

In order to make the automatic focusing system of the present application more convenient to be applied to an industrial production environment, so that the whole structure thereof is compact, and the display effect is better, in an embodiment, the automatic focusing system further includes a first beam splitter 50, a dichroic mirror 60, and a first tube mirror 70, wherein the splitting ratio of the first beam splitter 50 is 50/50 for the display effect, it can be understood that the performance of the first beam splitter 50 can be further adaptively adjusted according to the requirement. In the imaging process, the characteristic signal beam emitted from the lens (20a, 20b) is split by the first beam splitter 50 and emitted to the dichroic mirror 60, the dichroic mirror 60 reflects the characteristic signal beam to the objective lens 30 and reaches the object plane W, and the object plane W passes the characteristic signal beam through the objective lens 30, the dichroic mirror 60, the first beam splitter 50 and the first tube mirror 70 in sequence and emits the characteristic signal beam to the first camera 40 to form a characteristic image.

Further, in the practical application process, since the lenses (20a, 20b) include optical devices such as a barrel mirror, so that the distance between the adjacent lenses (20a, 20b) is relatively large, even larger than the effective diameter of the objective lens 30 for receiving light, in order to better converge the characteristic signal beam to the objective lens 30, the present application further includes a light converging component C, which is located between the lenses (20a, 20b) and the first beam splitter 50, and is used for converging the characteristic signal beam emitted by the lenses (20a, 20b) to the first beam splitter 50. As for the form of the light-focusing assembly C, the present application provides two exemplary embodiments, please refer to fig. 2, in an embodiment, the light-focusing assembly C includes a plurality of second beam splitters C1 and a plurality of light-focusing prisms C2, a second beam splitter C1 is correspondingly disposed on the light-emitting surface of each lens (20a, 20b), a light-focusing prism C2 is disposed between two adjacent second beam splitters C1, and the characteristic signal light beams emitted from the lenses (20a, 20b) are reflected to the first beam splitter 50 after passing through two mirror reflections of the second beam splitters C1 and the light-focusing prisms C2, in this embodiment, the second beam splitters C1 and the light-focusing prisms C2 provide mirror reflections to converge the characteristic signal light beams, so as to achieve effective convergence to the objective lens 30, and thus can better meet practical use requirements. Referring to fig. 3, in another embodiment, the light collecting assembly C includes a third beam splitter C3 and a fourth optical device C4 respectively disposed corresponding to two adjacent lenses (20a, 20b), wherein the fourth optical device C3 may adopt a beam splitter with a splitting ratio 50/50, a polarizing beam splitter or a dichroic mirror. The characteristic signal beam emitted from one of the two adjacent lenses (20a, 20b) is reflected by the third beam splitter C3 to the fourth optical device C4, reflected by the fourth optical device C4 and directed to the first beam splitter 50, and the characteristic signal beam emitted from the other of the two adjacent lenses (20a, 20b) is directed to the first beam splitter 50 after passing through the fourth optical device C4. While the present embodiment can also make the auto-focusing system of the present application better adapt to the actual use requirements, it can be understood that, as the technology is improved, the light-focusing assembly C can be omitted when the existing form of the lenses (20a, 20b) is made smaller in volume by modification, and the distance between the different lenses (20a, 20b) can be small and is consistent with the effective diameter of the objective lens 30 for receiving light, which is also within the protection scope of the present application.

Further, the autofocus system of the present application further includes an adjuster (not shown in the drawings); the processor generates an adjusting command according to the adjusting quantity and sends the adjusting command to the adjuster; the adjuster adjusts the position of the objective lens 30 according to the adjustment command. The regulator at least has three regulating dimensions, including x-direction rotation regulation and y-direction rotation regulation, and is used for automatic leveling; the z-direction movement adjustment is used for automatic focusing, and comprises a servo motor, a transmission mechanism and other components, which can refer to the existing structural design and are not described herein again.

Next, a description will be given of how to determine the defocus amount so that the controller can drive the object plane W by adjusting the amount control adjuster to adjust the position of the object plane W in the present embodiment.

Referring to fig. 7, the first light source 10a and the first light source 10b are respectively located on the focal planes of the lens 20a and the lens 20b, and the characteristic signal light beams emitted by the first light source 10a and the first light source 10b are converged on the focal plane of the objective lens 30. Defining the focal length of the lens 20a as f1 ', the focal length of the lens 20b as f2 ', the focal length of the objective lens 30 as f3 ', the heights of the first light source 10a and the first light source 10b on the focal planes of the first lens 20a and the first lens 20b as h1 and-h 2, the heights of the principal rays of the characteristic signal light beams of the first light source 10a and the first light source 10b on the exit plane of the objective lens 30 as a1 and-a 2, the distance from the exit plane of the objective lens 30 to the focal plane thereof as L1, and the defocus amount as- Δ L, then:

δh2′＝ΔL1*tan((h2′-a2)/L1) (4)；

δh1′＝ΔL1*tan((h1′′a1)/L1) (5)；

specifically, when h1 ═ h2 ═ 0 and h2 ═ h1 ═ 0, equations (4) and (5) become (6) and (7) as follows (see fig. 8):

δh2′＝-ΔL1*tan(a2/L1) (6)；

δh1′＝-ΔL1*tan(a1/L1) (7)；

further, defining the focal length of the first tube mirror 70 of the present application as ft 1', the optical magnification of the auto-focusing system is β 1, then:

β1＝ft1′/f3′ (8)；

on the light-sensing surface of the first camera 40, if the variation of the characteristic signal beam is δ t:

δt＝(δh1′+δh2′)*β1 (9)；

defining the focal length of the second tube lens 110 to be ft 2', the optical magnification of the auto-focusing system of the present application is β 2, then:

β2＝ft2′/f3′ (10)。

in one embodiment, the autofocus system of the present application further includes a second light source 80, a fourth beam splitter 90, a second tube mirror 110, and a second camera 120; the illumination light emitted from the second light source 80 is reflected by the fourth dichroic mirror 90 and emitted to the dichroic mirror 60, the dichroic mirror 60 performs a light splitting process on the illumination light and emits the illumination light to the objective lens 30, the illumination light passing through the objective lens 30 is projected onto the object plane W for illuminating the object to be detected on the object plane W, the object to be detected reflects the illumination light to form a reflection light, and the reflection light passes through the objective lens 30, the dichroic mirror 60, the fourth dichroic mirror 90 and the second tube mirror 110 in sequence and finally converges to the second camera 120. Wherein the splitting ratio of the fourth light splitter 90 is 50/50. That is, through the arrangement of the second light source 80, the fourth spectroscope 90, the second tube lens 110 and the second camera 120, after the automatic focusing is realized through the above-mentioned contents, the illumination light of the second light source 80 reflected by the fourth spectroscope 90 illuminates the whole object plane W through the objective lens 30, and is converged to the second camera 120 through the objective lens 30 and the second tube lens 110 after being reflected by the object plane W, and the light converged to the second camera 120 can clearly display the information containing the object plane W to be detected.

The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.