CN114088006A

CN114088006A - Confocal microscope system and optical lighting device thereof

Info

Publication number: CN114088006A
Application number: CN202010856792.8A
Authority: CN
Inventors: 陈亮嘉; 伍国玮; 周钰轩
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2022-02-25

Abstract

The invention provides a confocal microscope system and an optical illumination device thereof. The confocal microscope system comprises an optical illumination device. The optical lighting device comprises an optical module and an optical modulation unit. The optical module is used for generating a plurality of incident lights with a continuous spectrum or a quasi-single frequency spectrum. The light modulation unit is provided with a plurality of light modulation elements, each light modulation element is used for receiving incident light with different incident angles and modulating the incident light to form modulated light with a divergence angle range, so that the general diffraction effect generated by the plurality of reflection elements cannot destroy the continuity of a continuous spectrum, the spectrum pattern of the modulated light is close to the spectrum pattern of the continuous light source, or the receptivity of a rear-end optical system for aligning a single-frequency spectrum is ensured. By the characteristic, the optical lighting device is combined with the confocal microscope system, the spectrum integrity or the effective transmission of light energy can be kept, and the accuracy of surface appearance depth measurement can be improved.

Description

Confocal microscope system and optical lighting device thereof

Technical Field

The invention relates to an optical surface topography measurement technology, in particular to a confocal microscope system and an optical illumination device thereof, which can reduce spectrum loss, solve the problem of discontinuity of a continuous spectrum generated by a light modulation unit and the problem of loss of a quasi-single frequency spectrum, and improve the topography resolution precision.

Background

In the field of precision microstructure manufacturing, such as: in the fields of IC industry, semiconductor industry, LCD industry, electromechanical automation industry, and photoelectric measurement industry, the three-dimensional topography measurement procedure is an important procedure for ensuring the uniformity of the process quality. In the detection technology, because the optical or photoelectric combined method has the characteristics of high accuracy, non-contact and the like, the optical method is commonly used for detecting the tiny outline, thickness or size of an object at present. Many optical non-contact measurement techniques are widely used, including confocal measurement technique (confocal), phase shift interferometry (phase shift interferometry), white-light interference interferometry (white-light vertical scanning interferometry), etc., and different measurement techniques are suitable for different measurement conditions and different fields.

The principle of the traditional confocal measurement technology is that optical slice images of different depths are obtained in an optical vertical scanning measurement mode, defocusing signal filtering of a general achromatic objective is carried out through a pinhole (pinhole), reflected light and scattered light outside a focusing area are filtered, focusing surface information is reserved, optical slice images obtained at different depths are reconstructed through a computer, and three-dimensional space image information of an object to be measured can be obtained. Alternatively, the detection light is split into detection lights with different focusing depths by a dispersive objective lens, for example, the confocal detection sensor disclosed in the publication of U.S. published application No. US 2004/0109170 divides the light field into different wavelengths and focuses the light at different focusing positions. The reflected light is analyzed through the spectral imaging device, and the depth of the position to be measured is analyzed according to the depth corresponding to the wavelength with the strongest light intensity.

The traditional confocal measurement technology of common achromatic objective or the color confocal technology of resolving the object surface depth by using the chromatic dispersion objective so as to reduce the object surface appearance is adopted. In the multi-spot detection, there is a problem of cross talk (crosstalk) of the light source, which causes a problem of depth resolution. To solve such a problem, it is necessary to use an array type of light modulation unit, for example: digital Micromirror Device (DMD). The position of the detection light can be controlled through the DMD, and therefore large-area surface morphology detection is completed.

However, the method of using the DMD to reflect the incident light as the detection light source has a problem. The reflective elements on the DMD are a two-dimensional periodic array, and each piece of reflective elements may be in an angular interval, for example: +12 ° and-12 °. Referring to fig. 1A, when each reflective element 10 in the DMD is controlled to turn at a specific angle, a wavefront Iw of the incident light I modulated by collimation from the continuous spectrum light source is projected to the DMD and reflected by each reflective element 10. In FIG. 1A, each incident light is parallel to each other. As shown in fig. 1B, since the adjacent reflective elements 10 have a distance therebetween, the wavefronts Rw of the reflected light R of the adjacent reflective elements 10 have an Optical Path Difference (OPD), when the optical path difference divided by the wavelength is equal to an integer, the reflected wavefronts Rw of the adjacent reflective elements 10 are combined together, and the reflected wavefront of the normal vector perpendicular to the reference plane 800 is maintained; on the contrary, when the optical path difference divided by the wavelength is not equal to an integer, the reflected light wavefronts Rw of the adjacent reflective elements 10 have a phase difference therebetween, so that the reflected light wavefronts are not perpendicular to the normal vector of the reference plane. Such a phenomenon, detected by the spectral imaging device, may cause a problem of the discontinuous spectrum shown in fig. 1C, for example: in fig. 1C, OPD is 4.116 μm, so OPD/7 is 0.587 μm, OPD/8 is 0.513 μm, OPD/9 is 0.456 μm, and OPD/10 is 0.411 μm, and it can be found from the calculation that there are four quite prominent peaks in 587nm,513nm,456nm, and 411nm, which results in a spectrum discontinuity, and consequently, when calculating the surface depth, the resolution and accuracy of the surface profile depth are reduced due to the spectrum discontinuity. If the illumination source is quasi-monochromatic and has center wavelengths other than 587nm,513nm,456nm, and 411nm as in the above calculation, the back-end optics may not receive light at all.

In order to solve the above problem, if a collimating light module is used, the Numerical Aperture (n.a) of the rear color confocal module or the general achromatic objective lens at the entrance pupil must be considered, and if the n.a value at the entrance pupil is not enough, some light cannot pass through the color confocal module or all light cannot pass through the general achromatic objective lens, so that the illumination spectrum on the sample to be measured is seriously discontinuous or even there is no light. This limitation places considerable design constraints on the back-end optics, and increasing numerical aperture is the most convenient method, but it is necessary to change the distance between the back-end optics and the DMD or increase the size of the back-end optics, both of which cause design and manufacturing inconveniences and difficulties.

Another method is to directly image the light source on the rear end of the DMD using a critical illumination method, but this method is also very inefficient.

In view of the above, there is a need for a confocal microscopy system and an optical illumination device thereof to solve the problems of the prior art.

Disclosure of Invention

In order to solve the above-mentioned technical problems, an objective of the present invention is to provide an optical illumination device, which receives incident lights with different incident angles through a Spatial Light Modulator (SLM) and modulates the incident lights to form modulated lights with a divergence angle range, so that the total diffraction effect generated by a plurality of spatial light modulation elements does not destroy the spectral continuity of a continuous spectrum source, or ensure the receptivity of a rear-end optical system of a single-frequency spectrum source, so that the spectrum of the modulated lights is substantially the same as the continuous spectrum or the quasi-single-frequency spectrum of the incident lights, that is, the spectral pattern of the modulated lights is equal to or close to the spectral pattern of the light source, thereby avoiding the spectral distortion and maintaining the effect of the spectral integrity. That is, with the present invention, the spectrum of any point on the light modulation element projected by the light source module in a continuous spectrum is light having a continuous spectrum, for example: white light, which is in accordance with the spectrum of light produced by the most originating light source. The spectrum of the modulated light directed to the sample surface will then be continuous and consistent with or close to the spectrum of the most originating light source. If the light source module projects any point on the light modulation element by the quasi-single-frequency spectrum, the modulated light passing through the light source module can enter the rear-end optical system. Therefore, the light source module of the invention can achieve the effect that the light modulation element can transmit the complete spectrum to the surface of the sample or ensure the light receiving performance of the rear-end optical system.

It is also an object of the present invention to provide an optical illumination device, which in one embodiment uses kohler illumination (f: (a))

illumination) module can greatly increase the optical efficiency of DMD, so as to solve the problem that "in a DMD-based diffraction pattern confocal system, because of the illumination with collimated light, the DMD can generate severe diffraction and dispersion phenomena, resulting in a downstream (back-end) optical system, for example: objective lenses, or dispersive objective lenses, can only receive a relatively low proportion of the light energy, and the light efficiency is extremely poor.

It is another object of the present invention to provide a confocal microscope system, which uses an optical illumination device that receives incident lights with different incident angles through a reflective element and reflects the incident lights to form a reflected light with a divergence angle range, so that the total diffraction effect generated between the reflective elements does not cause the light intensity of a certain wavelength to be particularly strong in the 0 th order light direction, thereby maintaining the continuity of the spectrum. Because the reflected light can maintain the spectrum continuity and can not distort the spectrum, the object measuring light which is similar to the original incident light spectrum can be formed on the object to be measured after the dispersion of the dispersion objective lens, and because the original continuity of the spectrum of the object measuring light is maintained, the accuracy of the surface appearance depth measurement can be improved in the subsequent calculation process of depth reduction. In the case of a quasi-single-frequency spectrum source, the confocal microscope system provided by the present invention also receives incident light with different incident angles and reflects the incident light to form reflected light with a divergence angle range, so that the total diffraction effect generated among the plurality of reflective elements can ensure the back-end optical system, for example: the objective lens or the dispersion objective lens can receive the light energy from the front end and focus the light energy on the measured object to carry out measurement operation.

In one embodiment, the present invention provides an optical illumination device, which includes an optical module and an optical modulation unit. The optical module is used for generating a plurality of incident lights and has a continuous spectrum. The light modulation unit is provided with a plurality of light modulation elements, each light modulation element is used for receiving incident light with different incident angles and modulating the incident light to form modulated light with a divergence angle range, so that the spectrum continuity of the continuous spectrum source cannot be damaged by the total diffraction effect generated among the plurality of light modulation elements, and the spectrum pattern of the modulated light is close to the spectrum pattern of the continuous spectrum source. In another embodiment, if the spectrum of the incident light is a quasi-monochromatic spectrum source, the back-end optical system of the present invention can also effectively receive the light energy and the spectrum from the front-end system.

In one embodiment, the present invention provides a color confocal microscope system, which includes an optical illumination device, an objective lens and a depth detection module. The optical lighting device is provided with an optical module and an optical modulation unit, wherein the optical module is used for generating a plurality of incident lights, the optical modulation unit is provided with a plurality of optical modulation elements, and each optical modulation element is used for receiving the incident lights with different incident angles and modulating the incident lights into modulated lights with a divergence angle range. The objective lens receives the modulated light modulated by at least one light modulation element and projects the modulated light onto an object, and each modulated light is reflected by a corresponding detection position on the object to form at least one object detection light. The depth detection module is used for receiving the at least object detection light, analyzing the object detection light and further restoring the depth corresponding to each detection position.

In an embodiment, the optical module further includes a polarizing element for polarizing the plurality of incident lights to make the plurality of incident lights have a first polarization state and project to the first light modulation unit. The first light modulation unit is used for modulating the incident light, so that the modulated light has a second polarization state, and the first polarization state and the second polarization state are orthogonal to each other. The objective lens further comprises a quarter-wave plate and a dispersion objective lens, wherein the quarter-wave plate is used for modulating the modulated light into modulated light with a third polarization state, the dispersion objective lens receives the modulated light with the third polarization state to disperse the modulated light into dispersed light, each dispersed light has sub-light fields with different depths, each sub-light field has different wavelengths, the dispersion objective lens projects the at least one dispersed light onto an object, each dispersed light corresponds to a detection position on the object, each dispersed light is reflected by the corresponding detection position on the object to form at least one object measuring light, and the at least one object measuring light passes through the dispersion objective lens and then passes through the quarter-wave plate to form the object measuring light with the first polarization state. The depth detection module further comprises a second light modulation unit and a spectral imaging device, wherein the second light modulation unit is used for modulating the object detection light with the first polarization state into the object detection light with the second polarization state, and the spectral imaging device is used for analyzing the spectrum of the object detection light. The first light modulation unit and the second light modulation unit are respectively a silicon-based liquid crystal.

In one embodiment, the optical module further includes a light source, a first lens and a second lens. The light source generates a plurality of channels of light. The first lens is arranged on one side of the light source and used for receiving the multiple channels of light and focusing the multiple channels of light on a first area to form multiple channels of focused light. The second lens is arranged on one side of the first lens, so that the first lens is positioned between the light source and the second lens, the second lens is away from the focusing position by the distance of the focal length, each path of focusing light is diverged by the second lens to form a plurality of paths of incident light to be projected to all or part of the reflecting elements, each reflecting element receives the incident light from a plurality of different positions, and the incident light is further reflected to form reflected light with the divergence angle range.

In one embodiment, the objective lens is a dispersive objective lens, receives the reflected light reflected by the at least one reflecting element to modulate the reflected light into a dispersed light, each dispersed light has sub-modulated lights with different depths, each sub-modulated light has a different wavelength, the dispersive objective lens projects the at least one dispersed light onto an object, each dispersed light corresponds to a detection position on the object, and each dispersed light is reflected by the corresponding detection position on the object to form at least one object detection light.

Drawings

FIGS. 1A and 1B are schematic diagrams illustrating a reflective element on a DMD receiving incident light and reflected light in the prior art;

FIG. 1C is a schematic diagram of a discontinuous spectrum of incident light and reflected light received by a reflective element of a DMD in the prior art;

FIG. 2A is a schematic view of an optical illumination device according to an embodiment of the present invention;

FIG. 2B is a schematic view of an embodiment of the optical module;

FIG. 3 is a schematic diagram of the mirror of the light modulation unit of the present invention reflecting light having a range of divergent angles;

FIG. 4 is a schematic spectrum diagram of the reflected light formed after the light source generated by the optical illumination device of the present invention is reflected by each reflective element of the DMD;

FIG. 5 is a schematic view of another embodiment of the chromatic confocal microscopy system of the present invention;

FIG. 6 is a schematic view of another embodiment of the chromatic confocal microscopy system of the present invention;

FIG. 7 is a graph illustrating wavelength and light intensity curves of a detection location according to the present invention;

FIGS. 8A and 8B are schematic diagrams of different embodiments of confocal microscopy systems formed by using the optical illumination device of the present invention;

FIG. 9 is a schematic view of a surface-shaped color confocal system formed by using the optical illumination device of the present invention;

FIGS. 10A and 10B are schematic diagrams illustrating comparison of optical effects of an embodiment of the application of the optical illumination device of the present invention and a conventional optical device; and

fig. 11A and 11B are schematic diagrams illustrating comparison of optical effects of another embodiment of the optical illumination device of the present invention and a conventional optical device.

List of reference numerals: 10-a reflective element; 2-an optical lighting device; 20-an optical module; 21-a light modulation unit; 21 a-a first light modulation unit; 200-a light source; 201-a first lens; 202-a second lens; 203-focal position; 210. 210 a-a reflective element; 210 b-light modulation elements; 22-an objective lens; 23-a spectral imaging device; 3-a chromatic confocal microscopy system; 30-a dispersive objective lens; 31. 31 a-depth detection module; 310-a collimating lens; 311-an image acquisition unit; 311 a-lens; 312 a-a light sensor; 310 b-a filter; 311 b-spectral imaging means; 3110-a spectral spectroscopy unit; 3111-image sensing element; 313-a spectroscope; 314. 315-light intensity sensing module; 316-spatial filtering elements; 317-a lens; 318-light intensity sensor; 32-a light splitting element; 33-an arithmetic processing unit; 34-a depth detection module; 340-a second light modulation unit; 341-spectral imaging means; 342-a light-splitting element; 40-light; 40 a-40 c-light emitting positions; 41-focused light; 41 a-41 c-incident light; 42-reflected light; 42 a-42 c-reflected light; 43-dispersed light; 43a to 43 c-sub-modulated light; 44-object light measurement; 45a, 45 b-object light; 6-an object; 90. 90 a-incident light; 90b, 90 c-modulated light; 900-wavefront; 800-a reference plane; i-incident light; theta-convergence angle.

Detailed Description

Various exemplary embodiments may be described more fully hereinafter with reference to the accompanying drawings, in which some exemplary embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout. The optical illumination device and its conventional confocal or color confocal microscope system will be described in the following with reference to the drawings by various embodiments, which, however, should not be construed as limiting the invention.

Please refer to fig. 2A, which is a schematic diagram of an optical illumination apparatus according to an embodiment of the present invention. In this embodiment, the optical illumination device 2 includes an optical module 20 and an optical modulation unit 21. The optical module 20 is used to produceA plurality of incident light beams 90 having a continuous spectrum and a convergence angle θ are generated, i.e. the incident light beams 90 have a convergence angle, i.e. the boundaries of the incident light beams I are not parallel or nearly parallel. In this embodiment, the optical module 20 is a Kohler illumination (

instrumentation) module. Fig. 2B is a schematic view of an optical module according to an embodiment of the present invention. The optical module 20 has a light source 200, a first lens 201 and a second lens 202. The light source 200 is a surface light source in this embodiment, and is used for generating a plurality of light beams 40. The first lens 201 is disposed at one side of the light source 200 for receiving the plurality of lights 40 and focusing the plurality of lights 40 at a focusing position 203 to form a plurality of focused lights 41.

In one embodiment, since the optical module 20 is a kohler illumination module, the first lens 201 corresponds to an aperture stop (field stop) and the focusing position 203 corresponds to a field stop (field stop). The aperture bar is used to adjust the size of the illumination passing through the first lens 201, and the field of view bar is used to adjust the intensity of the illumination. In one embodiment, the aperture at the entrance pupil of the first lens 201 can be used as an aperture stop, and there are no optical elements in the field of view. In addition, in another embodiment, the aperture elements capable of adjusting the aperture size may be further disposed in the area of the aperture bar and the field of view bar for adjusting the illumination size and the illumination intensity.

The second lens 202 has a focal length f, and is disposed at one side of the first lens 201, such that the first lens 201 is located between the light source 200 and the second lens 202, the second lens 202 is located at a distance from the focal length f of the focusing position 203, the second lens 202 is configured to diverge the plurality of focused lights 41 to form incident lights, and project the incident lights to all or a portion of the plurality of reflective elements 210, such that each of the reflective elements 210 receives the focused lights 41 from different positions on the focusing position 203, and further reflects the focused lights to form reflected lights having divergent angle ranges.

The light modulation unit 21 has a plurality of light modulation elements, in this embodiment, each light modulation element is a reflection element 210, and each reflection element 210 can control the direction of the light beam projection. In one embodiment, the light modulation unit 21 is a DMD element, and each reflective element 210 thereon can change its rotation angle through telecommunication control, thereby assuming an on (on) or off (off) state. When light is incident on the plurality of reflective elements 210, the light determines a path of the reflected light according to a direction of deflection thereof. By the control unit 24, for example: the regulation and control of the devices or apparatuses with computing capability such as computers, microprocessors, notebook computers or workstations can control which reflective devices 210 reflect incident light to the object to be tested to form single-point or multi-point, single-line or multi-line, single-area or multi-area reflected light.

Referring to fig. 2B and fig. 3, fig. 3 is a schematic diagram of the reflection light with a divergent angle range reflected by the mirror of the light modulation unit according to the present invention. In the present embodiment, the solid lines represent incident lights 41a to 41c with different incident angles, and each incident light 41a to 41c is generated by different light-emitting positions 40a to 40c on the light source 200 or by focused lights at different positions on the focusing position 203. For example, in one embodiment, the incident light 41a is emitted from the light-emitting position 40a, the incident light 41b is emitted from the light-emitting position 40b, and the incident light 41c is emitted from the light-emitting position 40c, so that each of the reflective elements 210 receives light emitted from different positions on the light source 200, and each of the incident lights 41 a-41 c has a different incident angle relative to the reflective element 210. The reflective element 210 reflects the incident light beams 41a to 41c to form reflected light beams 42a to 42 c. The multiple reflected lights 42a to 42c have a divergence angle range θ e.

Referring back to fig. 2A, since each of the reflected lights reflected by the reflective elements 210 to 210a has a divergent angle, the total diffraction effect generated by the reflective elements 210 to 210a forms an illumination with a uniform spectrum in the angle range without damaging the integrity of the system spectrum, so that the reflected lights generated by each of the reflective elements 210 to 210a are collected by the objective lens 22 and analyzed by the spectral imaging device 23, as shown in fig. 4, the spectrum of the reflected lights is substantially the same as (i.e., the same as or similar to) the continuous spectrum respectively possessed by the plurality of incident lights 90 generated by the optical module 20, that is, the spectrum of the modulated light is substantially the same (i.e., the same as or similar to) the spectrum pattern generated by the optical module 20. As can be seen from the spectrum detection result shown in fig. 4, the problem of spectrum discontinuity is solved after the reflected light having the divergence angle range is reflected by each reflective element. It should be noted that, although the foregoing is described with reference to a continuous spectrum, in another embodiment, the incident light of the continuous spectrum may also be an incident light with a quasi-single frequency spectrum, and may also be modulated by the optical modulation structure of the present invention, so as to ensure a back-end optical system, for example: the objective lens 22 is aligned with the single-frequency spectrum receptivity, and the spectrum loss problem is avoided. The incident light of the quasi-monochromatic spectrum may be laser light, for example: semiconductor lasers or solid state lasers.

Referring to fig. 5, a schematic diagram of a color confocal microscope system according to an embodiment of the invention is shown. In the present embodiment, the color confocal microscope system 3 includes an optical illumination device 2, a dispersive objective lens 30 and a depth detection module 31. The optical illumination device 2 has an optical module 20 and an optical modulation unit 21, the optical module 20 is configured to generate a plurality of incident lights, the optical modulation unit 21 has a plurality of reflective elements 210, each of the reflective elements 210 is configured to receive the incident light with different incident angles and reflect the incident light to form a reflected light with a divergence angle range θ e. The optical illumination device 2 in the present embodiment can be implemented by using the optical architecture shown in fig. 2A and 2B. It should be noted that the size of the divergence angle θ e is not limited, and in one embodiment, the numerical aperture n.a of the dispersive objective lens 30 can be determined according to the requirement of a person skilled in the art.

The objective lens 30 receives the reflected light 42 reflected by the at least one reflecting element 210 to modulate the reflected light 42 into a dispersed light 43, each dispersed light 43 has sub-modulated lights 43 a-43 c with different depths, each sub-modulated light 43 a-43 c has a different wavelength, the objective lens 30 projects the at least one dispersed light 43 a-43 c onto an object 6, each dispersed light 43 corresponds to a detection position on the object 6, and each dispersed light 43 is reflected by the corresponding detection position on the object 6 to form at least one object light 44.

The object-detecting light 44 moves along the original optical path under the control of the light modulation unit 21, passes through the reflection element 210 and the light splitting element 32, and is received by the depth detection module 31. The depth detection module 31 is configured to receive the at least one object measurement light 44, and analyze the wavelength and the corresponding light intensity of the object measurement light 44, so as to restore the depth corresponding to each detection position. In this embodiment, the depth detection module 31 has a collimating lens 310 and an image capturing unit 311. The collimating lens 310 collimates the object detection light, and then enters the image capturing unit 311, and a corresponding light sensing signal is obtained through the lens 311a of the image capturing unit 311 and the light sensor 312 a. In one embodiment, the optical sensor 312a has a plurality of filter arrays for receiving the reflected at least one object-measuring light, each filter array having a plurality of filter elements for respectively allowing a specific wavelength of the object-measuring light to pass through. In one embodiment, the image capturing unit 311 may be an image capturing device developed by the belgium timing Microelectronics center (IMEC) and integrating a filter element and a CCD or CMOS optical sensor. The optical wavelength and the optical intensity signal (as shown in fig. 7) collected by the image collecting unit 311 are processed by the processing unit 33, for example: the computer or the workstation having the device for calculation processing is used to determine the depth of the detected position after calculation. For example: in fig. 7, after measurement and analysis, the position with the wavelength of 540nm has the maximum light intensity at the detection position corresponding to the dispersed light 43 in fig. 6, so that the depth of focus corresponding to the wavelength of 540nm is the depth of the detection position, and the corresponding relationship between the light wavelength intensity and the depth is the prior art, and is not repeated herein. It should be noted that, since the light source provided by the optical illumination device 2 of the present invention does not have the problem of spectral discontinuity after passing through the reflective element, a good depth analysis result can be obtained in the subsequent calculation of the optical signal and the depth analysis.

Referring to fig. 6, another embodiment of the color confocal microscope system of the present invention is shown. In the present embodiment, the optical structure is basically similar to that of fig. 5, except that the depth detection module 31a of the present embodiment is a combination of a filter 310b and a spectral imaging device 311b, and the filter 310b is a slit or a plurality of pinholes. After passing through the filter 310b, the object light 44 is sensed by the spectral imaging device 311 b. The spectral imaging device 311b further includes a spectral splitting unit 3110 and an image sensor 3111. The spectral splitting unit 3110, which splits the object light 44 into beams of different wavelengths. The image sensor 3111 is coupled to the spectrum splitting unit 3110 to sense light intensities of the split light beams with different wavelengths to form the spectrum image. The arithmetic processing unit 33 is connected to the spectral image sensing unit 311b for receiving the reflected light spectral image, performing an operation, and determining the depth of the detected position.

The foregoing embodiments are implementations applied to a dispersive objective lens. However, the optical illumination device of the present invention is not limited to a color confocal microscope system. As in the confocal system shown in fig. 8A, the optical illumination device 2 is applied to a differential confocal microscopy system, providing light source illumination. The objective lens 30a in the present embodiment is a general objective lens and does not have a dispersion function. In this embodiment, the object light reflected by the object 6 is split into two

object measuring lights

45a and 45b by a beam splitter 313. Each

object light

45a and 45b is sensed by the depth detection module 31 a. The depth detection module 31a of the present embodiment is a differential confocal detection module, which includes light

intensity sensing modules

314 and 315 respectively for receiving the

object light

45a and 45b to generate corresponding light intensity signals. In this embodiment, each of the light

intensity sensing modules

314 and 315 has a spatial filter element and a light intensity sensor (e.g., a camera), and the size (diameter or width) of each spatial filter element is different, i.e., the size of the pinhole or slit of the spatial filter element of the light intensity sensing module 314 is different from the size of the pinhole or slit of the spatial filter element of the light intensity sensing module 315. Each

object

45a or 45b passes through a corresponding spatial filter element before its light intensity is sensed by the light intensity sensor. Each of the light

intensity sensing modules

314 and 315 is electrically connected to the arithmetic processing unit 33. The arithmetic processing unit 33 receives each light intensity signal, and performs a signal processing on each light intensity signal to obtain a differential intensity signal ratio, and determines a measurement position depth corresponding to the differential intensity signal ratio.

In addition, as shown in fig. 8B, the figure is a schematic view of another embodiment of the confocal microscopy system of the present invention. In the present embodiment, basically similar to fig. 8A, the difference is that the object light reflected by the surface of the object 6 is received and guided to a depth detection module 31b after being split by the light splitting element 32. The depth detection module 31b in this embodiment is a spatial filter optical detection module, which has a spatial filter 316, a lens 317 and an optical intensity sensor 318. In this embodiment, the spatial filter element 316 is a Liquid Crystal On Silicon (LCOS) element, and can simulate a filter element by a digital control method, for example: a pinhole or a slit, filtering the object light. After passing through the spatial filter element 316, the object light is sensed by the light intensity sensor 318 through the lens 317, and a corresponding light intensity sensing signal is obtained. Finally, the depth of the detected position is obtained through calculation of the arithmetic processing unit 33.

Fig. 9 is a schematic diagram of a surface-shaped color confocal system formed by using the optical illumination device of the present invention. In the present embodiment, the system 3d includes an optical illumination device 2a, an objective lens 22a and a depth detection module 31 c. The optical illumination device 2a has an optical module 20 and a first light modulation unit 21a, wherein the optical module 20 is configured to generate a plurality of incident lights 90 having a continuous spectrum and a convergent angle. In this embodiment, the optical module 20 is a kohler lighting module, and the characteristics thereof are as described above and will not be described herein again. The optical module 20 further has a polarizer 204 for polarizing the plurality of incident lights to form an incident light 90a with a first polarization state, and the incident light is split and guided to the first light modulation unit 21a by a first light splitting element 205. The first light modulation unit 21a has a plurality of light modulation elements 210b, and each light modulation element 210b is configured to receive incident light with different incident angles and modulate the incident light to form modulated light with a divergence angle range. The modulation principle is as described above and will not be described herein.

The first light modulation unit 21a in this embodiment is a Liquid Crystal On Silicon (LCOS), each of which corresponds to an active control element, such as a CMOS, a reflective electrode, and a liquid crystal layer, LCOS is well known to those skilled in the art and will not be described in detail herein, the first light modulation unit 21a in the present embodiment can be used to change the polarity of light, therefore, when the incident light 90a with the first polarization state is projected to the first light modulation unit 21a, the first light modulation unit 21a modulates the incident light 90a to form a modulated light 90b, the modulated light 90b has a second polarization state, wherein the first polarization state and the second polarization state are orthogonal to each other, in the embodiment, the first polarization state is P-polarized light (P-polarized light), the second polarization state is S-polarized light.

The modulated light 90b is guided to the cylindrical lens group 206 by the beam splitter 205, and the cylindrical lens group 206 guides the modulated light 90b to the objective lens 30 a. In this embodiment, the objective lens further includes a quarter-wave plate 300 and a dispersive objective lens 301, wherein the quarter-wave plate 300 is used to modulate the modulated light 90b into a modulated light 90c with a third polarization state. In this embodiment, the third polarization state is a circular polarization state. The dispersive objective 301 receives the modulated light 90c with the third polarization state to disperse the modulated light 90c into a dispersed light 43, each dispersed light 43 has sub-light fields 43 a-43 c with different depths, and each sub-light field 43 a-43 c has a different wavelength. The objective lens 301 projects the at least one line of dispersed light 43 onto an object 6, each dispersed light 43 corresponds to a detection position on the object, each dispersed light 43 is reflected by the corresponding detection position on the object 6 to form the at least one object-measuring light 42a, and the at least one object-measuring light 42a has the third polarization state, and passes through the objective lens 301 and then the quarter wave plate 300 to form the object-measuring light 42b having the first polarization state.

The depth detection module 34 further includes a second light modulation unit 340, a spectrum imaging device 341, and a light splitting element 342, wherein the second light modulation unit 340 is configured to modulate the object-measuring light 42b with the first polarization state into the object-measuring light 42c with the second polarization state. In the present embodiment, the second light modulation unit 340 is a Liquid Crystal On Silicon (LCOS), and the structure thereof is the first light modulation unit 21a described above, which is not described herein again. The object measurement light 42c with the second polarization state further passes through the light splitting element 342 and enters the spectral imaging device 341. The spectral imaging device 341 is configured to analyze the spectrum of the object-measuring light, and further generate a corresponding spectral image. After the calculation of the arithmetic processing unit 33, the depth of each detected position is determined. The method of resolving depth from spectrum belongs to the prior art, and is not described herein.

Please refer to fig. 10A and 10B, which are schematic diagrams illustrating comparison of optical effects of an optical illumination device according to an embodiment of the present invention and a conventional optical device. The optical device of fig. 10A is a structure having a combination of an array-type light modulation unit 21 (hereinafter referred to as DMD) for collimating an incident light source and a DMD. For convenience of description, relevant optical elements through which the reflected light after being reflected from the DMD passes are omitted, and only one objective lens 22 is used for representative description, and in the present embodiment, the objective lens 22 is a dispersive objective lens. According to the conventional structure shown in fig. 10A, the incident light I incident on the DMD is a broadband light field, i.e., light with different color spectra, which is only illustrated by RGB three-color light for convenience of description. The light field of fig. 10A is collimated incident light I, i.e. the incident light does not have a convergence angle, i.e. the boundaries of the light field are parallel or nearly parallel. When the incident light is projected onto the DMD, the DMD reflects the incident light to the objective lens 22 and projects the incident light onto the object to be measured through a proper reflection angle control. By detecting the spectrum passing through the object 22 on the other side of the objective lens 22, a problem of discontinuous spectra is found, since some of the spectra, for example fig. 10A, red and blue light cannot be reflected onto the objective lens 22 smoothly due to the angles of reflection and divergence.

Of course, the Numerical Aperture (NA) of the objective lens can be increased by a user, or the objective lens can be moved to a position relatively close to the DMD to solve the problem, however, increasing the NA of the objective lens increases the size and cost of the optical system, and moving the objective lens to a position close to the DMD affects the arrangement of other optical elements of the optical system, i.e., the space between the reflected light and the objective lens is compressed, so that some optical elements cannot be arranged between the DMD and the objective lens. In addition, in the configuration of fig. 10A, if the light is monochromatic light, although there is no expectation that the spectral regions are continuous, after the light is reflected by the DMD, the optical path of the reflected light is small relative to the numerical aperture of the objective lens, that is, most of the light is reflected to other angles, and only a part of the light enters the objective lens 22, which affects the efficiency of light use.

Referring to fig. 10B, basically, the optical structure is the same as that of fig. 10A, except that the incident light 90 in fig. 10B is a broadband incident light with a convergence angle of 10 degrees in this embodiment, but not limited thereto. Incident light 90 is projected onto the DMD and reflected onto the objective lens 22, and it can be seen that in addition to green light G, a portion of both blue light B and red light R enter the objective lens 22, increasing the spectrum continuum. The smaller the spectral range loss, the wider the dispersion position generated by each color of light after the light is split by the objective lens, and therefore, the more accurate the depth range of the detected object surface topography.

Please refer to fig. 11A and 11B, which are schematic diagrams illustrating comparison of optical effects of another embodiment of the optical illumination apparatus of the present invention and a conventional optical apparatus. Fig. 11A shows a conventional optical structure, and the light modulation unit 21A is a modulation device of an LCOS (hereinafter, referred to as LCOS). Since the LCOS is used, a light splitting element 342 is disposed on the optical path. The incident light I shown in fig. 11A is the same as the incident light I shown in fig. 10A, and belongs to the collimated broadband incident light I, so that the light is split by the beam splitter 342 and guided to the LCOS, and then reflected to penetrate through the beam splitter 342 and enter the objective lens, and the spectrum discontinuity problem caused by the spectrum loss shown in fig. 10A also occurs. Similarly, if the light is monochromatic light, the light path of the reflected light is small relative to the numerical aperture of the objective lens, that is, most of the light is reflected to other angles, and only part of the light enters the objective lens 22, which affects the efficiency of light use, as shown in fig. 10A.

Therefore, as shown in fig. 11B, under the optical modulation of LCOS, the broadband incident light 90 with the convergence angle of the present invention is used, and the convergence angle in the present embodiment is 10 degrees, but not limited thereto. After the incident light 90 is projected to the LCOS, it is reflected to the objective lens 22 through the beam splitter 342, and it can be seen that almost all of the original incident spectrum enters the objective lens 22, and the original spectrum range is maintained. The smaller the spectral range loss, the wider the dispersion position generated by each color of light after the light is split by the objective lens, and therefore, the more accurate the depth range of the detected object surface topography.

According to the optical lighting device provided by the invention, the digital light modulation element receives the incident light with different incident angles and reflects the incident light to form the modulated light with a divergence angle range, so that the overall diffraction effect generated among the plurality of light modulation elements cannot damage the continuity of the spectrum, the spectrum pattern of the modulated light is close to the spectrum pattern of the continuous light source, the spectrum distortion is avoided to keep the spectrum integrity effect, and the accuracy of the detection of the surface topography of the object is further improved.

The above description is only for the purpose of describing preferred embodiments or examples of the present invention in terms of technical means for solving the problems, and is not intended to limit the scope of the present invention. The scope of the invention is to be determined by the following claims and their equivalents.

Claims

1. A confocal microscopy system, comprising:

an optical illumination device having an optical module and a first light modulation unit, the optical module being configured to generate a plurality of incident lights having a spectrum and a convergence angle, the first light modulation unit having a plurality of light modulation elements, each light modulation element being configured to receive the incident lights having different incident angles and modulate them to form a modulated light having a divergence angle range and having a substantially same or similar to the spectrum, wherein the spectrum may be a continuous spectrum or a quasi-single frequency spectrum;

the objective lens receives the at least one modulated light and projects the at least one modulated light to an object, each modulated light corresponds to a detection position on the object, and each modulated light is reflected by the corresponding detection position on the object to form at least one object detection light; and

and the depth detection module is used for receiving the at least object detection light, analyzing the object detection light and further restoring the depth corresponding to each detection position.

2. The confocal microscopy system of claim 1, wherein the optical illumination device further comprises:

a light source for generating multiple channels of light, each channel of light having the spectrum;

the first lens is arranged on one side of the light source and used for receiving the multiple channels of light and focusing the multiple channels of light on a first area to form multiple channels of focused light; and

the second lens is arranged on one side of the first lens, so that the first lens is positioned between the light source and the second lens, the second lens is away from the focusing position by the distance of the focal length, each path of focused light is dispersed by the second lens to form a plurality of paths of incident light to be projected to all or part of the modulation element, each modulation element receives the incident light from a plurality of different positions, and the incident light is modulated by the incident light to form modulated light with the dispersion angle range.

3. The confocal microscopy system of claim 2, wherein the first and second lenses are each plano-convex or biconvex lenses.

4. The confocal microscopy system of claim 1, wherein the depth detection module further comprises:

a light splitting element arranged on a light path of the at least one object measuring light and used for guiding the at least one object measuring light;

a collimating lens set arranged at one side of the light splitting element for collimating and modulating the at least one object detection light passing through the light splitting element; and

and the image acquisition unit is arranged on one side of the collimating lens group and used for receiving the at least one object detection light so as to generate a corresponding light intensity sensing signal.

5. The confocal microscopy system of claim 1, wherein the depth detection module further comprises a filter and a spectral imaging device.

6. The confocal microscopy system of claim 1, wherein the depth detection module is a differential confocal detection module or a spatial filtering detection module.

7. The confocal microscopy system of claim 1, wherein the objective lens is a dispersive objective lens receiving the modulated light modulated by the at least one modulation element to disperse the modulated light into a dispersed light, each dispersed light having sub-light fields of different depths, each sub-light field having a different wavelength, the dispersive objective lens projecting the at least one dispersed light onto an object, each dispersed light corresponding to a detection location on the object, each dispersed light being reflected from the corresponding detection location on the object to form the at least one object-measuring light.

8. The confocal microscopy system of claim 1, wherein the optical module further comprises a polarizer for polarizing the plurality of incident lights such that the plurality of incident lights have a first polarization state and are projected onto the first light modulation unit.

9. The confocal microscopy system of claim 8, wherein the first light modulation unit is configured to modulate the incident light such that the modulated light has a second polarization state, the first polarization state and the second polarization state being orthogonal to each other.

10. The confocal microscopy system of claim 9, wherein the objective lens further comprises a quarter-wave plate for modulating the modulated light to a modulated light having a third polarization state and a dispersive objective lens for receiving the modulated light having the third polarization state to disperse the modulated light into dispersed light, each dispersed light having sub-fields with different depths, each sub-field having a different wavelength, the dispersive objective lens projecting the at least one dispersed light onto an object, each dispersed light corresponding to a detection location on the object, each dispersed light being reflected from the corresponding detection location on the object to form the at least one object light, the at least one object light passing through the dispersive objective lens and then passing through the quarter-wave plate to form the object light having the first polarization state.

11. The confocal microscopy system of claim 10, wherein the depth detection module further comprises a second light modulation unit and a spectral imaging device, the second light modulation unit is configured to modulate the object measurement light with the first polarization state into the object measurement light with the second polarization state, and the spectral imaging device is configured to analyze a spectrum of the object measurement light.

12. The confocal microscopy system of claim 11, wherein the first light modulation unit and the second light modulation unit are each a liquid crystal on silicon.

13. An optical illumination device, comprising:

an optical module for generating a plurality of incident lights with a convergence angle and having a spectrum; and

the light modulation unit is provided with a plurality of light modulation elements, each light modulation element is used for receiving incident light with different incident angles and modulating the incident light to form modulated light with a divergence angle range, so that the continuity of the spectrum is not damaged by the total diffraction effect generated among the plurality of modulation elements, the spectrum of the modulated light is substantially the same as the spectrum, and the spectrum can be a continuous spectrum or a quasi-single-frequency spectrum.

14. The optical illumination device as claimed in claim 13, wherein the optical module further comprises:

a light source for generating a plurality of light beams at different emission positions;

the first lens is arranged on one side of the light source and used for receiving the multiple channels of light and focusing the multiple channels of light at a focusing position to form multiple channels of focused light; and

the second lens is arranged on one side of the first lens, so that the first lens is positioned between the light source and the second lens, the second lens is away from the focusing position by the distance of the focal length, each path of focusing light is diverged by the second lens to form a plurality of paths of incident light to be projected to all or part of the reflecting elements, each reflecting element receives the incident light from a plurality of different positions, and the incident light is further reflected to form reflected light with the divergence angle range.

15. An optical lighting device as recited in claim 14, wherein said first and second lenses are each plano-convex or biconvex lenses.

16. The illumination device as claimed in claim 13, wherein the optical module further comprises a polarizer for polarizing the incident lights to make the incident lights have a first polarization state and project the polarized lights to the light modulation unit.

17. The illumination device as claimed in claim 16, wherein the light modulation unit is configured to modulate the incident light such that the modulated light has a second polarization state, and the first polarization state and the second polarization state are orthogonal to each other.

18. The confocal microscopy system of claim 17, wherein the light modulation unit is a liquid crystal on silicon.