TW202107139A - Optical illumination device and confocal microscopy system using the same - Google Patents

Abstract

The present invention provides an optical illumination device comprising an optical module and an optical modulator. The optical module is utilized to generate a plurality of incident lights with a continuous spectrum or quasi-monochromatic spectrum. The optical modulator has a plurality of modulating elements, each of which is utilized to receive the incident lights having different incident angle and is utilized to modulate the incident lights to form a modulating light field having a specific divergent angle whereby the continuous spectrum is kept as its original, or the downstream optical system can receive the light spectrum properly. In one embodiment, the optical illumination device is available to combine with the confocal microscopy system for reducing the spectrum lost and maintaining completeness of the spectrum thereby enhancing the accuracy of surface profile inspection.

Description

Optical illuminating device and its confocal microscopy system

The present invention is an optical surface topography measurement technology, in particular to a method that can reduce spectrum loss, solve the problem of discontinuity caused by continuous spectrum passing through light modulation unit, and loss of quasi-single frequency spectrum, so as to improve the accuracy of topography An optical lighting device and its confocal microscopy system.

In the field of precision microstructure manufacturing processes, such as: IC industry, semiconductor industry, LCD industry, electromechanical automation industry, photoelectric measurement industry and other fields, the process of three-dimensional topography measurement is an important process to ensure uniform process quality. In the detection technology, due to the high accuracy and non-contact characteristics of optical or photoelectric combined methods, optical methods are commonly used to detect the tiny outline, thickness or size of objects. At present, many optical non-contact measurement technologies have been widely used, including confocal microscopy, phase shifting interferometry, white-light vertical scanning technology (white-light vertical scanning). Interferometry), etc., different measurement techniques are suitable for different measurement conditions and different fields.

The principle of the traditional confocal measurement technology is to obtain optical slice images of different depths by the optical vertical scanning measurement method. The defocus signal of the general achromatic objective lens is filtered by a pinhole to reduce the focus area. The outside reflected light and scattered light are filtered out, the focal plane information is retained, and the optical slice images obtained at different depths are reconstructed by the computer to obtain the three-dimensional image information of the object to be measured. Another method is to divide the detection light into detection light with different focal depths through a dispersive objective lens. For example, the confocal detection sensor disclosed in the US Published Application No. US. Pub. No. 2004/0109170 is Divide the light field into different wavelengths and focus on different focus positions respectively. The reflected light is then analyzed by 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.

Whether it is the traditional confocal measurement technology using general achromatic objective lenses, or the color confocal technology using dispersive objective lenses to analyze the depth of the surface of the object, and then restore the surface topography of the object. In the case of multi-point detection, there will be a problem of cross talk between light sources, which in turn causes problems in depth resolution. In order to solve such problems, it is necessary to use array-type light modulation units, such as Digital Micromirror Device (DMD). Through the DMD, the position of the detection light can be controlled to complete a large-area surface topography detection.

However, using the DMD to reflect incident light as a way to detect the light source also has problems. The reflective element on the DMD is a two-dimensional periodic array, and each reflective element can be in an angular interval, for example: +12⁰ and -12⁰. Please refer to FIG. 1A, when each reflective element 10 in the DMD is controlled to turn to a specific angle, the wavefront Iw of the incident light I, which is collimated and modulated by the continuous-spectrum light source, is projected to the DMD and is reflected by each reflective element 10 . In Figure 1A, each incident light is parallel to each other. As shown in FIG. 1B, due to the spacing between adjacent reflective elements 10, the wavefront Rw of the reflected light R of the adjacent reflective elements 10 has an optical path difference (OPD). Therefore, when the optical path difference is divided by When the wavelength is equal to an integer, the wavefront Rw of the reflected light from adjacent reflective elements 10 will be combined to maintain the wavefront of the reflected light perpendicular to the normal vector of the reference plane 800; on the contrary, when the optical path difference is divided by the wavelength not equal to the integer At this time, there will be a phase difference between the reflected light wavefronts Rw of adjacent reflective elements 10, so that the reflected light wavefronts will not be perpendicular to the normal vector of the reference plane. And this kind of phenomenon, through the detection of the spectral imaging device, you will find the problem of the discontinuous spectrum as shown in Figure 1C. For example, in Figure 1C, OPD=4.116μm, so OPD/7=0.587μm, OPD/8= 0.513μm, OPD/9=0.456μm, OPD/10=0.411μm. According to the calculation, it can be known that there will be four prominent peaks in 587nm, 513nm, 456nm and 411nm, resulting in discontinuity of the spectrum, which leads to subsequent calculations on the surface At the depth, the resolvability and accuracy of the depth of the surface topography are reduced due to the discontinuity of the spectrum. If the illuminating light source is a quasi-single-frequency spectrum and its center wavelength is not 587nm, 513nm, 456nm and 411nm in the above calculation example, the back-end optical system may not receive light at all.

In order to solve the above problems, if a collimated light module is used, the numerical aperture (NA) of the rear color confocal module or general achromatic objective lens at the entrance pupil must be considered. If the NA value at the entrance pupil is not enough, Part of the light cannot pass through the color confocal module or all the light cannot pass through the general achromatic objective lens, resulting in serious discontinuities in the illumination spectrum on the sample under test, or even no light. This limitation makes the design of the back-end optical system have considerable limitations, so increasing the numerical aperture is the most convenient method, but this must change the distance between the back-end optical system and the DMD, or increase the back-end optical system. The lens size of the system, but these two methods will cause a lot of inconvenience and difficulty in design and manufacturing.

Another method is to use critical illumination to directly image the light source on the back end of the DMD, but this method is also quite poor in light efficiency.

In summary, there is a need for an optical illuminating device and a confocal microscopy system to solve the problems caused by conventional technologies.

The present invention provides an optical lighting device, which receives incident light with different incident angles through spatial light modulator (SLM), and modulates it to form modulated light with a range of divergence angles, so that the plurality of spatial light modulators The overall diffraction effect produced will not damage the spectral continuity of the continuous spectrum source, or ensure the receptivity of the optical system at the back of the quasi-single-frequency spectrum source, so that the spectrum of the modulated light is substantially the same as the continuous spectrum of the incident light. The quasi-single-frequency spectrum is the same, that is, the spectral pattern of the modulated light is equal to or close to the spectral pattern of the light source, avoiding spectral distortion and maintaining the effect of spectral integrity. In other words, through the present invention, the spectrum of the light source module projected at any point on the light modulation element with a continuous spectrum is light with a continuous spectrum, such as white light, which is consistent with the spectrum of the light generated by the most source light source. The spectrum of the modulated light guided to the sample surface will be continuous and consistent or similar to the spectrum of the source light source. And if the light source module is projected on any point on the light modulation element with a quasi-single frequency spectrum, the modulated light afterwards can all enter the back-end optical system. Therefore, through the light source module of the present invention, it is possible to achieve the effect of allowing the light modulation element to deliver the complete spectrum to the sample surface or ensuring the light receptivity of the back-end optical system.

The present invention provides an optical illumination device. In one embodiment, a Köhler illumination module is used to illuminate the DMD, so that the light efficiency can be greatly increased to solve the DMD-based diffraction map confocal system In, because of the use of collimated light illumination, DMD will produce serious diffraction and dispersion phenomena, resulting in downstream (rear) optical systems, such as objective lenses or dispersive objectives, can only receive a relatively low proportion of light energy, light efficiency Very bad question.

The present invention provides a confocal microscopy system, which utilizes an optical illuminating device that receives incident light with different incident angles through a reflective element, and reflects it to form a reflected light with a range of divergence angles. The overall diffraction effect produced will not cause the light intensity of certain wavelengths in the direction of the 0-order light to be particularly strong, thereby maintaining the continuity of the spectrum. Since the reflected light can maintain the continuity of the spectrum without distorting the spectrum, after the dispersion of the dispersive objective lens, the measured object light can be formed on the object to be measured, which is close to the original incident light spectrum, because the spectrum of the measured object light remains the original Therefore, the accuracy of surface topography depth measurement can be improved during the subsequent depth reduction calculation process. In the case of a quasi-single-frequency spectrum source, the confocal microscopy system provided by the present invention also receives incident light with different incident angles, and reflects it to form reflected light with a range of divergence angles, so that the plurality of reflective elements The resulting overall diffraction effect can ensure that the back-end optical system, such as an objective lens or a dispersive objective lens, can receive the light energy from the front end and focus it on the object to be measured for measurement.

In one embodiment, the present invention provides an optical lighting device including an optical module and a light modulation unit. The optical module is used to generate a plurality of incident lights and has a continuous spectrum. The light modulation unit has a plurality of light modulation elements, and each light modulation element is used to receive incident light with different incident angles, and modulate it to form modulated light with a range of divergence angles, so that one of the plurality of light modulation elements The overall diffraction effect generated by the time does not destroy the spectral continuity of the continuous spectrum source, so that the spectral pattern of the modulated light is close to the spectral pattern of the continuous light source. In another embodiment, if the spectrum of the incident light is a quasi-single-frequency spectrum source, the back-end optical system of the present invention can also effectively receive the light energy and spectrum from the front-end system.

In one embodiment, the present invention provides a color confocal microscopy system, which includes an optical illumination device, an objective lens, and a depth detection module. An optical lighting device, which has an optical module and a light modulation unit, the optical module is used to generate a plurality of incident light, the light modulation unit has a plurality of light modulation elements, each light modulation element is used to receive Incident light with different incident angles is modulated to form modulated light with a range of divergent angles. The objective lens receives modulated light modulated by at least one light modulating element, and projects the at least one 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 light . The depth detection module is used to receive the at least object light, analyze the object light, and restore the depth corresponding to each detection position.

In one embodiment, the optical module further includes a polarizing element for polarizing the plurality of channels of incident light so that the plurality of channels of incident light has a first polarization state and is projected to the first light Modulation unit. The first light modulation unit is used to modulate 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 includes a quarter wave plate and a dispersive objective lens. The quarter wave plate is used to modulate the modulated light into modulated light having a third polarization state. The dispersive objective lens receives The modulated light in the third polarization state is used to disperse the modulated light into a dispersive light. Each dispersive light has sub-fields of different depths, and each sub-field has a different wavelength. The dispersive objective lens projects the at least one dispersive light onto a On the object, each dispersive light corresponds to a detection position on the object, and each dispersive light is reflected by the corresponding detection position on the object to form the at least one object light, and the at least one object light passes through the dispersive objective lens Then, it passes through the quarter wave plate to form the object light with the first polarization state. Wherein, the depth detection module further has a second light modulation unit and a spectral imaging device, and the second light modulation unit is used to modulate the object light having the first polarization state to have the second polarization Polar object light, the spectral imaging device is used to analyze the spectrum of the object light. The first light modulation unit and the second light modulation unit are respectively a liquid crystal on silicon.

In one embodiment, the optical module further includes a light source, a first lens, and a second lens. The light source generates plural rays of light. The first lens is arranged on one side of the light source, and the first lens is used for receiving the plurality of lights and focusing the plurality of lights on the first area to form a plurality of focused lights. The second lens has a focal length, and is arranged on one side of the first lens so that the first lens is located between the light source and the second lens, the second lens is separated from the focal position by the focal length, and the second lens The lens is used to diverge each focused light to form multiple incident lights and project them to all or a part of the reflective element, so that each reflective element receives the incident light from a plurality of different positions, and then reflects to form a range of the divergence angle Reflected light.

In one embodiment, the objective lens is a dispersive objective lens that receives reflected light reflected by at least one reflective element to modulate the reflected light into a dispersive light. Each dispersive light has a different depth of sub-modulated light, and each sub-modulated light With different wavelengths, the dispersive objective lens projects the at least one dispersive light onto an object, and each dispersive light corresponds to a detection position on the object, and each dispersive light is reflected by a corresponding detection position on the object to form at least one Measure object light.

Hereinafter, various exemplary embodiments may be more fully described with reference to the accompanying drawings, and some exemplary embodiments are shown in the accompanying drawings. However, the inventive concept may be embodied in many different forms, and should not be construed as being limited to the exemplary embodiments set forth herein. To be precise, the provision of these exemplary embodiments makes the present invention detailed and complete, and will fully convey the scope of the concept of the present invention to those skilled in the art. Similar numbers always indicate similar components. Hereinafter, various embodiments and drawings will be used to illustrate the optical illumination device and its conventional confocal or color confocal microscopy system. However, the following embodiments are not intended to limit the present invention.

Please refer to FIG. 2A, which is a schematic diagram of an embodiment of an optical lighting device of the present invention. In this embodiment, the optical lighting device 2 includes an optical module 20 and a light modulation unit 21. The optical module 20 is used to generate a plurality of incident light 90 with a continuous spectrum and a convergence angle θ, that is, the incident light 90 has a convergence angle, that is, the boundary of the incident light I is not a parallel or nearly parallel light field. In this embodiment, the optical module 20 is a Kohler illumination module. As shown in FIG. 2B, the figure is a schematic diagram of an embodiment of the optical module 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 to generate a plurality of lights 40. The first lens 201 is arranged on one side of the light source 200 to receive the plurality of lights 40 and focus the plurality of lights 40 at the focus 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 is equivalent to an aperture stop, and the focus position 203 is equivalent to a 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 an embodiment, the opening at the entrance of the first lens 201 can be used as an aperture bar, and there is no optical element in the field of view. In addition, in another embodiment, an aperture element capable of adjusting the size of the aperture can be placed in the area of the aperture bar and the field of view, so as to adjust the illumination size and intensity.

The second lens 202 has a focal length f and is arranged on one side of the first lens 201, so that the first lens 201 is located between the light source 200 and the second lens 202, and the second lens 202 is away from the focus position 203 At the distance of the focal length f, the second lens 202 is used to diverge the plurality of focused lights 41 to form incident light, and project to all or a part of the plurality of reflective elements 210, so that each reflective element 210 receives the focused light The focused light 41 at different positions at the position 203 is further reflected to form a reflected light with a divergent angle range.

The light modulation unit 21 has a plurality of light modulation elements. In this embodiment, each light modulation element is a reflective element 210, and each reflective element 210 can control the direction of light beam projection. In one embodiment, the light modulation unit 21 is a DMD element, and each reflective element 210 on it can change its rotation angle through the control of telecommunications, and then present an on or off state. When light is projected to a plurality of reflective elements 210, the light will determine the path of the reflected light according to the direction in which the light is deflected. Through the control of the control unit 24, such as a computer, a microprocessor, a notebook computer, or a workstation, and other components or devices with arithmetic processing capabilities, it is possible to control which reflective components 210 reflect incident light to the object to be measured to form a single point or multiple points. Point, single line or multi-line, single area or multi-area reflected light.

Please refer to FIG. 2B and FIG. 3, where FIG. 3 is a schematic diagram of the reflected light having a divergence angle range reflected by the reflector of the light modulation unit of the present invention. In this embodiment, the solid lines represent the incident light 41a~41c with different incident angles. Each incident light 41a~41c is generated by a different light-emitting position 40a~40c on the light source 200, or is caused by a different focus position 203. The location of the focused light is generated. For example, in one embodiment, the incident light 41a is the light emitted by the light-emitting position 40a, the incident light 41b is the light emitted by the light-emitting position 40b, and the incident light 41c is the light emitted by the light-emitting position 40c. For each reflective element 210, it receives light emitted from different positions on the light source 200, and each incident light 41a-41c has a different incident angle with respect to the reflective element 210. The reflective element 210 reflects the plurality of incident lights 41a to 41c to form a plurality of reflected lights 42a to 42c. The plurality of reflected lights 42a to 42c have a divergence angle range θe.

Returning to Figure 2A, since each reflected light reflected by the reflective elements 210~210a has a divergent angle, the overall diffraction effect produced by the reflective elements 210~210a will form a uniform spectrum of illumination in this angle range. , So as not to damage the integrity of the system's spectrum, so that the reflected light generated by each reflective element 210~210a is collected by the objective lens 22, and then analyzed by the spectral imaging device 23, the spectrum of the reflected light can be known, as shown in the figure As shown in 4, the continuous spectra of the multiple incident lights 90 generated by the optical module 20 are substantially the same, that is, the spectra of the modulated light are substantially the same (meaning the same or similar) to those of the optical module 20. The resulting spectral graph. It can be seen from the spectrum detection result shown in FIG. 4 that the problem of spectral discontinuity is resolved after each reflective element reflects the reflected light with a divergent angle range. It should be noted that although the foregoing description is based on continuous spectrum, in another embodiment, the incident light of continuous spectrum can also be incident light with quasi-single frequency spectrum, which can also be modulated by the light modulation structure of the present invention. It can ensure that the back-end optical system, such as the objective lens 22, is aligned with the receptivity of the single-frequency spectrum without causing the problem of spectrum loss. The aforementioned incident light of the quasi-single frequency spectrum may be laser light, for example, semiconductor laser light or solid-state laser light.

Please refer to FIG. 5, which is a schematic diagram of an embodiment of the color confocal microscope system of the present invention. In this embodiment, the color confocal microscope system 3 includes an optical illuminating device 2, a dispersive objective lens 30 and a depth detection module 31. The optical illuminating device 2 has an optical module 20 and a light modulation unit 21. The optical module 20 is used to generate a plurality of incident lights. The light modulation unit 21 has a plurality of reflective elements 210, each of which reflects The element 210 is used to receive incident light with different incident angles, and reflect it to form a reflected light with a divergent angle range θe. The optical illuminating device 2 in this embodiment can be implemented using the optical architecture shown in FIGS. 2A and 2B. It should be noted that the size of the divergence angle range θe is not limited. In one embodiment, it can be determined according to the numerical aperture N.A of the dispersive objective lens 30, which can be determined by those skilled in the art according to requirements.

The dispersive objective lens 30 receives the reflected light 42 reflected by at least one reflective element 210 to modulate the reflected light 42 into a dispersive light 43. Each dispersive light 43 has a different depth of sub-modulated light 43a~43c, and each sub-modulated light 43a~43c have different wavelengths. The dispersive objective lens 30 projects the at least one dispersive light 43a~43c onto an object 6. Each dispersive light 43 corresponds to a detection position on the object 6, and each dispersive light 43 passes through the object 6. The corresponding detection position on 6 reflects at least one object light 44.

The object light 44 is controlled by the light modulation unit 21, moves along the original light path, 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 used to receive the at least one object light 44 and analyze the wavelength and corresponding light intensity of the object light 44 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. After collimating the object light, the collimating lens 310 enters the image capturing unit 311, and senses the corresponding light sensing signal through the lens 311a of the image capturing unit 311 and the light sensor 312a. . In one embodiment, the light sensor 312a has a plurality of filter arrays for receiving the reflected at least one object light, and each filter array has a plurality of filter elements to allow the object light of a specific wavelength to pass through. In one embodiment, the image capturing unit 311 may be an image capturing device developed by the Belgian Interuniversity Microelectronics Centre (IMEC) that integrates filter elements and CCD or CMOS optical sensors. The light wavelength and light intensity signal extracted by the image capturing unit 311 (as shown in FIG. 7) are processed by the arithmetic processing unit 33, such as a computer or a workstation with arithmetic processing devices, and then used to determine The depth of the detection position. For example: in Figure 7, it corresponds to the detection position corresponding to the dispersive light 43 in Figure 6. After measurement and analysis, it can be known that the position with the wavelength of 540nm has the maximum light intensity, so the focal depth corresponding to the wavelength of 540nm can be obtained. It is the depth of the detection position, and the corresponding relationship between the intensity of the light wavelength and the depth is a conventional technique, and will not be repeated here. It should be noted that since the light source provided by the optical illuminating 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.

Please refer to FIG. 6, which is a schematic diagram of another embodiment of the color confocal microscope system of the present invention. In this embodiment, it is basically similar to the optical architecture of FIG. 5, except that the depth detection module 31a of this embodiment is a combination of a filter 310b and a spectral imaging device 311b, and the filter 310b is a slit or It is composed of multiple pinholes. After the object light 44 passes through the filter 310b, it is sensed by the spectral imaging device 311b. The spectral imaging device 311b further includes a spectral beam splitting unit 3110 and an image sensor 3111. The spectrum splitting unit 3110 divides the object light 44 into light beams of different wavelengths. The image sensing element 3111 is coupled to the spectral beam splitting unit 3110 to sense the light intensity of the beams of different wavelengths to be split to form the spectral image. The arithmetic processing unit 33 is connected to the spectral image sensing unit 311b to receive the reflected light spectral image, and after performing calculation, it is used to determine the depth of the detection position.

The foregoing embodiment is an implementation aspect applied to a dispersive objective lens. But in fact, 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 illuminating device 2 is applied to a differential confocal microscopy system to provide light source illumination. The objective lens 30a in this embodiment is a general objective lens and does not have the function of dispersion. In this embodiment, a beam splitter 313 is used to split the object light reflected by the object 6 into two measuring object lights 45a and 45b. Each object light 45a and 45b is sensed by the depth detection module 31a. The depth detection module 31a of this embodiment is a differential confocal detection module, which includes light intensity sensing modules 314 and 315 for receiving object light 45a and 45b to generate corresponding light intensity signals. In this embodiment, each light intensity sensing module 314 and 315 has a spatial filter element and a light intensity sensor (such as a camera), and the size (diameter or width) of each spatial filter element is different, that is, the light The size of the pinhole or slit of the spatial filter element of the 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 light 45a or 45b first passes through the corresponding spatial filter element, and then its light intensity is sensed by the light intensity sensor. Each light intensity sensing module 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 the differential intensity signal ratio, and determines the measurement position depth corresponding to the differential intensity signal ratio.

In addition, as shown in FIG. 8B, this figure is a schematic diagram of another embodiment of the confocal microscope system of the present invention. In this embodiment, it is basically similar to FIG. 8A. The difference is that the object light reflected from the surface of the object 6 in this embodiment is split by the light splitting element 32 and then guided to a depth detection module 31b. The depth detection module 31b in this embodiment is a spatial filter optical detection module, which has a spatial filter element 316, a lens 317, and a light intensity sensor 318. In this embodiment, the spatial filter element 316 is a Liquid Crystal on Silicon (LCOS) element. Through digital control, it can simulate filter elements, such as pinholes or slits, to filter the object light. . After the object light passes through the spatial filter element 316, it passes through the lens 317 and is sensed by the light intensity sensor 318 to obtain a corresponding light intensity sensing signal. Finally, after calculation by the arithmetic processing unit 33, the depth of the detected position is obtained.

As shown in FIG. 9, the figure is a schematic diagram of the surface-shaped color confocal system formed by the optical illumination device of the present invention. In this embodiment, the system 3d includes an optical illuminating device 2a, an objective lens 22a, and a depth detection module 31c. The optical illuminating device 2a has an optical module 20 and a first light modulation unit 21a. The optical module 20 is used to generate incident light 90 with a continuous spectrum and a convergent angle. In this embodiment, the optical module 20 is a Kohler lighting module, the characteristics of which are as described above, and will not be repeated here. The optical module 20 further has a polarizing element 204 for polarizing the plurality of incident lights to form incident light 90a having a first polarization state, and dichroically guiding it to the second beam through a first beam splitting element 205 A light modulation unit 21a. The first light modulation unit 21a has a plurality of light modulation elements 210b, and each light modulation element 210b is used to receive incident light with different incident angles and modulate it to form modulated light with a range of divergence angles. The modulation principle is as mentioned above, and will not be repeated here.

The first light modulation unit 21a in this embodiment is a liquid crystal on silicon (LCOS), and each light modulation element corresponds to an active control element, such as a CMOS, a reflective electrode, and a structure of a liquid crystal layer. LCOS is a well-known element to those skilled in the art and will not be described in detail here. The first light modulation unit 21a in this embodiment can be used to change the polarity of light, so when the incident light 90a has the first polarization state After being 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 And the second polarized state are orthogonal to each other. In this embodiment, the first polarized state is P-polarized light, and the second polarized state is S-polarized light. .

The modulated light 90b is guided to the cylindrical lens group 206 via the light splitting element guide 205, and the cylindrical lens group 206 then guides the modulated light 90b to the objective lens 30a. In this embodiment, the objective lens further includes a quarter-wave plate 300 and a dispersive objective lens 301. The quarter-wave plate 300 is used to modulate the modulated light 90b into a third polarization state. Modulated light 90c. In this embodiment, the third polar state is a circular polar state. The dispersive objective lens 301 receives the modulated light 90c with the third polarization state to disperse the modulated light 90c into a dispersive light 43. Each dispersive light 43 has sub-light fields 43a-43c with different depths, and each sub-light field 43a~ 43c has different wavelengths. In this embodiment, only three sub-light fields 43a-43c are used to represent the RGB three colors, but this number is not limited. The dispersive objective lens 301 projects the at least one dispersive light 43 onto an object 6. Each dispersive light 43 corresponds to a detection position on the object, and each dispersive light 43 is formed by reflection from a corresponding detection position on the object 6. The at least one object light 42a and the at least one object light 42a have the third polarization state, and after passing through the dispersive objective lens 301, pass through the quarter wave plate 300 to form a first polarization State of the object light 42b.

The depth detection module 34 further has a second light modulation unit 340, a spectral imaging device 341, and a beam splitting element 342. The second light modulation unit 340 is used to adjust the object light 42b having the first polarization state. The object light 42c having the second polarization state is produced. In this embodiment, the second light modulation unit 340 is a liquid crystal on silicon (LCOS), and its structure is the same as that of the first light modulation unit 21a described above, and will not be repeated here. The object light 42c with the second polarization state further passes through the light splitting element 342, and then enters the spectral imaging device 341. The spectral imaging device 341 is used to analyze the spectrum of the object light to generate corresponding spectral images. After calculation by the arithmetic processing unit 33, the depth of each detection position is determined. The method of analyzing the depth from the spectrum is a conventional technique, so I won’t repeat it here.

Please refer to FIG. 10A and FIG. 10B, which are schematic diagrams illustrating the comparison of optical effects between an embodiment of the optical lighting device of the present invention and the conventional optical device. The optical device in FIG. 10A is a structure with a combination of a collimated incident light source and an array of DMD light modulation units 21 (hereinafter referred to as DMD). For the convenience of description, the relevant optical elements through which the reflected light after reflection from the DMD passes are omitted, and only an objective lens 22 is used as a representative for illustration. In this embodiment, the objective lens 22 is a dispersive objective lens. According to the conventional architecture shown in FIG. 10A, the incident light I incident on the DMD is a broadband light field, that is, includes light with different color spectra. For the convenience of description, only RGB three-color light is used for illustration. The light field in FIG. 10A is collimated incident light I, that is, the incident light does not have a convergence angle, that is, the boundary of the light field is parallel or almost parallel. When the incident light is projected onto the DMD, after proper reflection angle control, the DMD will reflect the incident light to the objective lens 22 and project it onto the object to be measured. By detecting the spectrum passing through the object environment 22 on the other side of the objective lens 22, the problem of the discontinuous spectrum will be found. This is because some spectra, in Figure 10A, for example, the red light and blue light are reflected and diverged due to the angle , It cannot be reflected on the objective lens 22 smoothly.

Of course, users can increase the numerical aperture (NA) of the objective lens, or move the objective lens to a position quite close to the DMD to solve this problem. However, increasing the numerical aperture of the objective lens will increase the volume and cost of the optical system. Moving the objective lens to a position close to the DMD will affect the setting of other optical elements of the optical system, that is, the space between the reflected light and the objective lens is compressed, so that some optical elements cannot be set between the DMD and the objective lens. In addition, under the architecture of FIG. 10A, if it is monochromatic light, although there will be no continuous lifting of the spectral part, after DMD reflection, 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.

Please refer to FIG. 10B. Basically, the optical architecture is the same as that of FIG. 10A. The difference is that the incident light 90 in FIG. 10B is a broadband incident light with a convergence angle. In this embodiment, the convergence angle is 10 degrees, but this is not the case. As a limit. The incident light 90 is projected onto the DMD and then reflected on the objective lens 22. It can be seen that in addition to the green light G, part of the blue light B and red light R will enter the objective lens 22, increasing the continuous range of the spectrum. The less the range loss of the spectrum, the wider the dispersion position of each color light after the objective lens is split. Therefore, the more accurate the depth range of the surface topography can be detected.

Please refer to FIGS. 11A and 11B, which are schematic diagrams illustrating the comparison of optical effects between another embodiment of the optical lighting device of the present invention and the conventional optical device. FIG. 11A shows a conventional optical architecture, and its light modulation unit 21a is an LCOS modulation device (hereinafter referred to as LCOS). Because of the use of LCOS, a light splitting element 342 is provided on the optical path. The incident light I shown in FIG. 11A is the same as that shown in FIG. 10A. It belongs to the collimated broadband incident light I. Therefore, it passes through the light splitting element 342 and is guided to the LCOS, and then passes through the light splitting element 342 to enter the spectrum of the objective lens. Characteristic, it will also produce the problem of spectral discontinuity caused by spectral loss as shown in Figure 10A. Similarly, if it is monochromatic light, as shown in Figure 10A, 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 portion of the light enters. The objective lens 22 affects the efficiency of light use.

Therefore, as shown in FIG. 11B, under the optical modulation of the LCOS, the broadband incident light 90 with a convergence angle of the present invention is used. The convergence angle in this embodiment is 10 degrees, but this is not a limitation. After the incident light 90 is projected to the LCOS, it passes through the beam splitter 342 and is reflected on the objective lens 22. It can be seen that almost all of the original incident light spectrum will enter the objective lens 22, maintaining the original spectrum range. The less the range loss of the spectrum, the wider the dispersion position of each color light after the objective lens is split. Therefore, the more accurate the depth range of the surface topography can be detected.

Through the optical illuminating device provided by the present invention, the incident light with different incident angles is received through the digital light modulation element, and reflected to form the modulated light with a divergence angle range, so that the total generated between the plurality of light modulation elements The diffraction effect does not destroy the continuity of the spectrum, making the spectrum pattern of the modulated light close to the spectrum pattern of the continuous light source, avoiding spectral distortion and maintaining the effect of spectral integrity, thereby improving the accuracy of surface topography detection.

The above description only describes the preferred implementations or examples of the technical means adopted by the present invention in order to solve the problems, and is not used to limit the scope of implementation of the patent of the present invention. That is to say, all the equivalent changes and modifications made in accordance with the scope of the patent application of the present invention or made in accordance with the scope of the patent of the present invention are all covered by the scope of the patent application of the present invention.

10: Reflective element 2: Optical lighting device 20: Optical module 21: Light modulation unit 21a: First light modulation unit 200: Light source 201: First lens 202: Second lens 203: Focus position 210, 210a: Reflective element 210b : Light modulation element 22: Objective lens 23: Spectral imaging device 3: Color confocal microscope system 30: Dispersive objective lens 31, 31a: Depth detection module 310: Collimating lens 311: Image capture unit 311a: Lens 312a: Light sensing Filter 310b: Filter 311b: Spectral imaging device 3110: Spectroscopy unit 3111: Image sensing element 313: Spectroscope 314, 315: Light intensity sensing module 316: Spatial filter element 317: Lens 318: Light intensity sensor 32: Spectroscopic element 33: Operation processing unit 34: Depth detection module 340: Second light modulation unit 341: Spectral imaging device 342: Spectroscopic element 40: Light 40a~40c: Light emitting position 41: Focused light 41a~41c: Incident Light 42: Reflected light 42a~42c: Reflected light 43: Dispersive light 43a~43c: Sub-modulated light 44: Measuring object light 45a, 45b: Object light 6: Object 90, 90a: Incident light 90b, 90c: Modulated light 900: Wavefront 800: Reference plane I: Incident light θ: Convergence angle

1A and FIG. 1B are schematic diagrams of receiving incident light and reflected light by the reflective element on the DMD in the conventional technology; 1C is a schematic diagram of the discontinuous spectrum of the incident light and the reflected light received by the reflective element on the DMD in the conventional technology; 2A is a schematic diagram of an embodiment of an optical lighting device of the present invention; 2B is a schematic diagram of an embodiment of the optical module; FIG. 3 is a schematic diagram of the reflected light having a divergence angle range reflected by the reflector of the light modulation unit of the present invention; 4 is a schematic diagram of the spectrum of the reflected light formed by the light source generated by the optical lighting device of the present invention after being reflected by the reflective elements of the DMD; 5 is a schematic diagram of another embodiment of the color confocal microscope system of the present invention; Fig. 6 is a schematic diagram of another embodiment of the color confocal microscopy system of the present invention; 7 is a schematic diagram of a curve of wavelength and light intensity of a detection position of the present invention; 8A and 8B are schematic diagrams of different embodiments of the confocal microscopy system formed by the optical illumination device of the present invention; 9 is a schematic diagram of a surface-shaped color confocal system formed by the optical lighting device of the present invention; 10A and 10B are schematic diagrams illustrating the comparison of optical effects between an embodiment of the optical illuminating device application of the present invention and a conventional optical device; and 11A and 11B are schematic diagrams illustrating the comparison of optical effects between another embodiment of the optical lighting device application of the present invention and the conventional optical device.

2: Optical lighting device

20: Optical module

21: light modulation unit

200: light source

201: The first lens

202: second lens

203: focus position

210: reflective element

40: light

40a~40c: light-emitting position

41: focus light

Claims (18)

A confocal microscope system, including: An optical lighting device, which has an optical module and a first light modulation unit, the optical module is used to generate a plurality of incident light having a spectrum and a convergence angle, the first light modulation unit has A plurality of light modulating elements, each light modulating element is used to receive incident light with different incident angles, and modulate it to form modulated light with a divergence angle range and substantially the same or similar to the spectrum, wherein the spectrum can be It is continuous spectrum or quasi-single frequency spectrum; An objective lens that receives the at least one modulated light and projects the at least one modulated light onto an object. Each modulated light corresponds to a detection position on the object, and each modulated light system is detected correspondingly on the object The position is reflected to form at least one object light; and A depth detection module is used to receive the at least object light, analyze the object light, and restore the depth corresponding to each detection position. The confocal microscopy system described in item 1 of the scope of patent application, wherein the optical illuminating device further includes: A light source generates a plurality of lights, and each light has the spectrum; A first lens arranged on one side of the light source, the first lens being used for receiving the plurality of lights and focusing the plurality of lights on the first area to form a plurality of focused lights; and A second lens having a focal length, arranged on one side of the first lens so that the first lens is located between the light source and the second lens, the second lens is separated from the focal position by the focal length, the second lens The lens is used to diverge each focused light to form multiple incident lights and project them to all or a part of the modulating element, so that each modulating element receives incident light from a plurality of different positions, and then modulates the incoming light to form Modulated light having this divergence angle range. According to the confocal microscopy system described in item 2 of the scope of patent application, the first and second lenses are plano-convex or double-convex lenses, respectively. For the confocal microscopy system described in item 1 of the scope of patent application, the depth detection module further includes: A light splitting element arranged on an optical path of the at least one object light for guiding the at least one object light; A collimating lens group arranged on one side of the light splitting element for collimating and modulating the at least one object light passing through the light splitting element; and An image capturing unit is arranged on one side of the collimating lens group to receive the at least one object light to generate a corresponding light intensity sensing signal. According to the confocal microscopy system described in claim 1, wherein the depth detection module further includes a filter element and a spectral imaging device. According to the confocal microscopy system described in claim 1, wherein the depth detection module is a differential confocal detection module or a spatial filter detection module. The confocal microscopy system described in item 1 of the scope of patent application, wherein the objective lens is a dispersive objective lens that receives modulated light modulated by at least one modulating element to disperse the modulated light into a dispersive light, and each dispersive light has a different depth. Light field, each sub-light field has a different wavelength, the dispersive objective lens projects the at least one piece of dispersive light onto an object, and each dispersive light corresponds to a detection position on the object, and each dispersive light system passes through the corresponding corresponding on the object The detecting position reflects to form the at least one object light. According to the confocal microscopy system described in claim 1, wherein the optical module further includes a polarizing element for polarizing the plurality of incident lights so that the plurality of incident lights have a first polarization state , And projected to the first light modulation unit. The confocal microscopy system described in item 8 of the scope of patent application, wherein the first light modulation unit is used to modulate the incident light so that the modulated light has a second polarization state, the first polarization state and the The second polar states are orthogonal to each other. The confocal microscopy system described in item 9 of the scope of patent application, wherein the objective lens further includes a quarter wave plate and a dispersive objective lens, and the quarter wave plate is used to modulate the modulated light to have a The modulated light in the third polarization state. The dispersive objective lens receives the modulated light in the third polarization state to disperse the modulated light into a dispersed light. Each dispersed light has sub-fields of different depths, and each sub-field has With different wavelengths, the dispersive objective lens projects the at least one dispersive light onto an object, and each dispersive light corresponds to a detection position on the object, and each dispersive light is reflected by a corresponding detection position on the object to form the at least one The measuring object light, the at least one measuring object light, after passing through the dispersive objective lens, then passes through the quarter wave plate to form the measuring object light having the first polarization state. For the confocal microscopy system described in claim 10, the depth detection module further has a second light modulation unit and a spectral imaging device, and the second light modulation unit is used to have the first polarizer The object light in the second polarized state is modulated into the object light with the second polarization state, and the spectral imaging device is used for analyzing the spectrum of the object light. According to the confocal microscopy system described in claim 11, the first light modulation unit and the second light modulation unit are each a liquid crystal on silicon. An optical lighting device, including: An optical module for generating a plurality of incident lights having a convergence angle, and having a spectrum; and A light modulation unit has a plurality of light modulation elements, and each light modulation element is used to receive incident light with different incident angles, and modulate it to form modulated light with a range of divergence angles, so that the plurality of modulation elements The resulting overall diffraction effect does not destroy the continuity of the spectrum, so that 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. For the optical illuminating device described in item 13 of the scope of patent application, the optical module further includes: A light source, which produces multiple beams of light at different emission positions; A first lens arranged on one side of the light source, the first lens is used to receive the plurality of lights and focus the plurality of lights at a focus position to form a plurality of focused lights; and A second lens having a focal length, arranged on one side of the first lens so that the first lens is located between the light source and the second lens, the second lens is separated from the focal position by the focal length, the second lens The lens is used to diverge each focused light to form multiple incident lights and project them to all or a part of the reflective element, so that each reflective element receives the incident light from a plurality of different positions, and then reflects to form a range of the divergence angle Reflected light. In the optical lighting device described in item 14 of the scope of patent application, the first and second lenses are respectively plano-convex or double-convex lenses. The optical illuminating device as described in item 13 of the scope of patent application, wherein the optical module further includes a polarizing element for polarizing the plurality of channels of incident light so that the plurality of channels of incident light has a first polarization state , And projected to the light modulation unit. As described in the 16th patent application, the light modulation unit is used to modulate the incident light so that the modulated light has a second polarized state, the first polarized state and the second polarized state The partial polarities are orthogonal to each other. The confocal microscopy system described in item 17 of the scope of patent application, wherein the light modulation unit is a liquid crystal on silicon.

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