WO2020235883A1 - Optical system using spatial light modulator, and physical property measurement method using same - Google Patents

Optical system using spatial light modulator, and physical property measurement method using same Download PDF

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Publication number
WO2020235883A1
WO2020235883A1 PCT/KR2020/006441 KR2020006441W WO2020235883A1 WO 2020235883 A1 WO2020235883 A1 WO 2020235883A1 KR 2020006441 W KR2020006441 W KR 2020006441W WO 2020235883 A1 WO2020235883 A1 WO 2020235883A1
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Prior art keywords
light
sample
optical system
spatial light
light modulator
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PCT/KR2020/006441
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French (fr)
Korean (ko)
Inventor
박희재
김진용
김민규
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서울대학교산학협력단
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Publication of WO2020235883A1 publication Critical patent/WO2020235883A1/en

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/21Polarisation-affecting properties
    • G01N21/211Ellipsometry
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/01Arrangements or apparatus for facilitating the optical investigation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/21Polarisation-affecting properties
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/02Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the intensity of light
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/08Mirrors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2201/00Features of devices classified in G01N21/00
    • G01N2201/06Illumination; Optics
    • G01N2201/063Illuminating optical parts
    • G01N2201/0638Refractive parts
    • G01N2201/0639Sphere lens

Definitions

  • the present invention relates to an optical system using a spatial light modulator and to measurement of physical properties of a sample using the same.
  • Ellipsometry is a method of measuring the physical properties of a sample by using the change in polarization characteristics of light.
  • the measuring equipment using the ellipsometry method is called an ellipsometer. After the incident light is polarized into a desired shape and incident on the sample, the polarization state of light reflected from the sample (reflective ellipsometer) or transmitted (transmitted ellipsometer) is measured. It measures physical properties such as complex refractive index, dielectric function, electrical conductivity, and crystal state such as lattice structure.
  • a reflective ellipsometer can be used to measure the thickness of a multilayer thin film. Compared to other thin film thickness measurement methods, it is a non-contact-non-destructive method, is applicable to transparent materials or dielectric thin films, and has excellent resolution. In the spotlight, it is widely used in the display and semiconductor industries.
  • the Ellipsometric Microscope introduced by KR Neumaier in 2000, introduced a vertical microscope structure to enable high-magnification imaging, but the optical component was physically (manually or at least) to adjust the polarization state. There was a limit in that it had to be adjusted mechanically.
  • a position of a polarizer must be adjusted or a mirror that moves finely within the microscope must be arranged, and the physical movement of such an optical element itself causes vibration to cause noise. This is problematic in that there is a risk of breaking the optical alignment between optical elements, which are kept extremely sensitive, as well as to generate ).
  • the operator After each measurement, the operator has to spend a considerable amount of time to remove noise and restore optical alignment after each measurement, and it is difficult to secure reliability for each measurement. For this reason, elliptical polarization microscopes are not widely used until now.
  • An object of the present invention is to provide an optical system using a spatial light modulator and a method for measuring physical properties using the same.
  • the above object can be achieved by a method of measuring an optical system and physical properties including the features of the claims to be described later.
  • the optical system using the spatial light modulator according to the present invention When the optical system using the spatial light modulator according to the present invention is used, it is possible to measure the physical properties of a sample without driving a motor, and since the possibility of interference of noise due to mechanical manipulation is reduced, more accurate and fast measurement is possible.
  • the advantages of the conventional elliptical polarization microscope that is, the advantages of high lateral resolution and high resolution imaging are maintained in the optical system according to the present invention.
  • FIG. 1 is a conceptual diagram showing the basic structure of an elliptic system according to the prior art.
  • FIG. 2 is a conceptual diagram illustrating a general structure of an optical system, that is, an arrangement of optical elements and an optical path according to an embodiment of the present invention.
  • FIG. 3 is a conceptual diagram showing the structure of an optical system when a digital light projector or an LCoS microdisplay is used as a spatial light modulator in the optical system according to an embodiment of the present invention.
  • FIG. 4 is a conceptual diagram showing a structure of an optical system when a transmission type liquid crystal display is used as a spatial light modulator in the optical system according to an embodiment of the present invention.
  • 5 and 6 are conceptual diagrams illustrating a digital light projector that is an example of a spatial light modulator of an optical system and a digital micromirror device that is an element constituting the digital light projector according to an embodiment of the present invention.
  • FIG. 7 is a conceptual diagram showing a single device of an LCoS type microdisplay that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
  • FIG. 8 is a conceptual diagram showing a single element of a transmission type liquid crystal display that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
  • FIG. 9 is a conceptual diagram showing that the color and polarization state of the liquid crystal transmits differently according to the voltage applied to the transmissive LC cell, which is a single element of a transmissive liquid crystal display, which is an example of a spatial light modulator of an optical system according to an embodiment of the present invention. .
  • FIGS. 10 and 11 are conceptual diagrams for explaining characteristics of a rear focal plane in an optical system according to an embodiment of the present invention.
  • 12 and 13 are conceptual diagrams for explaining a relationship between incident light and reflected light in an optical system of an optical system according to an embodiment of the present invention.
  • 14 to 17 are conceptual diagrams for explaining a method of measuring physical properties by adjusting a position to be illuminated on a rear focal plane by a spatial light modulator in an optical system according to an exemplary embodiment of the present invention.
  • FIG. 1 is a conceptual diagram showing the basic structure of an elliptic system according to the prior art.
  • the light source on the left serves to generate and emit incident light, and various light sources having an intensity and wavelength of an LED, laser or other known type may be used.
  • the emitted incident light passes through a polarization state generator (PSG) to have a desired polarization state.
  • the polarization state generator may consist of one or more various optical elements, such as a polarizer, a compensator, also called a retarder, and a phase modulator. These optical elements and their role are well known to those skilled in the art. Like electric devices, it is possible to adjust the incident light to have a desired polarization state (linear polarization, circular polarization, elliptical polarization) by combining these optical devices.
  • the incident light passing through the polarization state generator is incident on the surface of the sample with a certain angle ( ⁇ i ).
  • Incident light is divided into transmissive light that passes through the sample from the sample surface and reflected light that is reflected from the sample.
  • the plane perpendicular to the sample determined by incident light and reflected light is called a plane of incidence.
  • Reflected light is not only the light directly reflected from the sample surface, but also the light transmitted through the upper sample surface after the above-described transmitted light travels inside the sample and is reflected from the surface with another medium disposed at the bottom of the sample, or It is reflected downwards, proceeds to the bottom, and is reflected again from the surface of the other medium at the bottom to form an overlapping form of light transmitted through the upper sample surface.
  • a polarized state analyzer is placed on the path of the reflected light to analyze the state, for example, by extracting only light of a specific polarization component. By measuring the intensity or the like, the state of the reflected light can be determined.
  • a photodetector at the end of the path of reflected light measures the intensity of light and converts it into an electrical signal.
  • the photodetector may be a photodiode, a CCD, etc., and generally cannot measure the component or phase of light, but only measure the intensity, but by adjusting the polarization state analyzer, for example, rotating the polarizer included in the polarization state analyzer. By doing so, it is possible to calculate the polarization state of light by allowing only light of a specific polarization state to pass through and sensing the intensity of light according to each polarization state.
  • the polarization state of light may be calculated by adjusting the incident light incident on the sample by rotating the polarizer included in the polarization state generator instead of the polarization state analyzer.
  • the state vector of light has the form of a 1 ⁇ 2 matrix.
  • the first row component of the matrix is p-polarized, that is, a transverse magnetic mode in which the direction of vibration of the magnetic field is perpendicular to the incident plane.
  • the second row component means s polarization, that is, a transverse electric mode (TE mode) in which the vibration direction of the electric field is perpendicular to the incident surface.
  • the p-polarized and s-polarized components are perpendicular to each other.
  • p polarized light is
  • s polarized light is
  • the given light can be completely represented by the intensity and phase of this p-polarized and s-polarized light.
  • optical elements and specimens through which light passes on the optical path can be represented as a 2 ⁇ 2 matrix, and become an operator (2 ⁇ 2 matrix) acting on a given vector of light (1 ⁇ 2 matrix).
  • the polarizer The compensator is And the sample is (assuming isotropic material) Becomes.
  • the state of light that is deformed while passing through an optical element or sample is compared to the action of transforming the light vector by an operator.
  • the polarization state generator or the polarization state analyzer is a combination of optical elements represented by the above 2 ⁇ 2 matrix, the whole may be expressed as a single 2 ⁇ 2 matrix by obtaining the product of the 2 ⁇ 2 matrix corresponding to the elements included therein. have.
  • the result of light coming out of the light source and passing through the polarization state generator, the sample, and the polarization state analyzer can be expressed as follows.
  • the light source (the vector on the far right) has only p polarization for convenience of discussion.
  • the light source when light comes out of the light source, it can have both p-polarized and s-polarized components, but by placing a polarizing plate at the introduction part of the polarization state generator, it can be converted into a state vector having only a specific component as above.
  • the vector on the far right is the light from the light source
  • the matrix on the left is the transformation by the polarization state generator (PSG)
  • the matrix on the left is the sample
  • the two matrices on the left are the polarization state analyzer (PSA).
  • the leftmost matrix means that only light whose polarization direction matches the angle (A) of the polarization state analyzer is passed based on the incident surface of the polarization state analyzer.
  • the polarization state generator and the polarization state analyzer are composed of only a polarizer, and have a function of leaving only a linear polarization component corresponding to the axial angle of the polarizer, and P and A are variables representing the axial angle.
  • r p and r s contain information on various properties of a material, it is the goal of ellipsometry to find the values of r p and r s by adjusting the settings of the light source, polarization state generator, and polarization state analyzer.
  • the degree of matching may be based on, for example, a variance of an error between a numerical value according to a predicted value and an actual measured value, and those skilled in the art may set a standard for measuring the degree of matching in various ways.
  • FIG. 2 is a conceptual diagram illustrating a general structure of an optical system, that is, an arrangement of optical elements and an optical path according to an embodiment of the present invention.
  • a light source 110 and a spatial light modulator 120 are shown on the left side of the optical system 100.
  • the light source 110 and the spatial light modulator 120 can be combined in various forms, in FIG. 2 dealing with a general structure of an optical system, a diagram is replaced without showing an optical path.
  • FIGS. 3 and 4 dealing with a specific configuration of an optical system according to the type of spatial light modulator, the light source 110 and the spatial light modulator 120 will be shown in a separate form.
  • the light source 110 is a part that generates light that is a source of incident light of the optical system, and may generate and use light of a single wavelength or light having a spectrum of a certain range.
  • the spatial light modulator 120 is a device that modulates light in space to create a desired image. While the polarization state generator or the polarization state analyzer of FIG. 1 receives incident light and filters out only components of a specific polarization state or delays the phase by a predetermined amount, the spatial light modulator is a beam of a given light. With respect to the cross section, a specific portion passes light and a specific portion does not pass light, so that the input light is output in a state having a shape desired by the user.
  • a portion that becomes the smallest unit that allows or does not pass light is defined as a pixel, and the state in which each pixel passes light is on, and the state in which light does not pass is off. I will call it.
  • the spatial light modulator 120 may look like a surface light source or a display in which pixels are arranged in a certain array.
  • the pixels may have an arbitrary arrangement, for example, in the form of a two-dimensional rectangular array.
  • each pixel may correspond to a coordinate of a Cartesian coordinate system.
  • the pixels may be in the form of a two-dimensional circular array.
  • each pixel may correspond to the coordinates of the pole coordinate system.
  • the present invention is not limited to a specific arrangement method of each pixel of a spatial light modulator or a method of turning on/off the pixel, that is, a specific driving method.
  • the spatial light modulator 120 is not limited to a specific implementation method, and may be understood as referring to a device that creates and outputs an image desired by a user for input light.
  • the user can control the on/off of each pixel using a control module (not shown in the drawing) connected to the spatial light coordinate device, and accordingly, can draw a desired image as specified in advance.
  • a control module not shown in the drawing
  • An exemplary type of spatial light modulator 120 will be discussed in detail later.
  • the light modulated by the spatial light modulator 120 passes through the optional relay lenses 130a, 130b, which prevents the beam diameter on the optical path from becoming too wide and keeps the beam constant. It is intended to be limited within range.
  • a polarizer 130c and a compensator 130d are illustrated as examples. However, these are exemplary devices, and a person skilled in the art may construct other types of polarization state generators using other devices.
  • the light passing through the polarization state generator has a polarization state of a desired value, and in this state, the path is bent by the beam splitter 140 and goes to the bottom of the drawing.
  • the path of light passing through the objective lens is bent by the action of the lens, and is incident on the special point of the specimen 300. This completes the incident path.
  • the reflected light having a change in the polarization state by the sample at the point of incidence is emitted from the sample and passes through the objective lens 150 again, and then passes through the rear focal plane 200 and the beam splitter 140 and goes to the top of the drawing. And passes through elements corresponding to the polarization state analyzer.
  • a polarizer 160 is shown as an example.
  • the reflected light passing through the polarization state analyzer passes through the eyepiece 170 and reaches the light detector 180.
  • the light reaching the photodetector is converted into an electrical signal, and the optical device, for example, the polarizer 130c, is rotated to measure the change in intensity of the photodetector accordingly to analyze the physical properties of the above-described sample.
  • the paths of the incident light and the reflected light and the configuration of the above-described elements are exemplary, and those skilled in the art can design an optical system suitable for the purpose by varying the combination of optical elements while maintaining the essential configuration of the present invention. It is included.
  • FIG. 3 is an optical system in the case of using a digital light projector (DLP) or a liquid crystal on silicon (LCoS) microdisplay as the spatial light modulator 120 in the optical system according to an embodiment of the present invention. It is a conceptual diagram showing the structure of. The detailed structure and operation method of the digital light projector will be described in detail in FIGS. 5 and 6 and the related description, and the specific structure and operation method of the LCoS type microdisplay will be described in detail in FIG. 7 and the related description.
  • DLP digital light projector
  • LCDoS liquid crystal on silicon
  • the light source 110 is not arranged coaxially or in a straight line with the spatial light modulator 120 in the optical path.
  • the light source 110 is incident on the spatial light modulator 120 at an oblique angle and then reflected.
  • the digital light projector and the LCoS microdisplay are exemplified as the case where the light source 110 is not arranged coaxially or in a straight line with the spatial light modulator 120, but other spatial light modulators 120 are also similar. Alternatively, it may be used in other ways, and all such modifications are included in the scope of the present invention.
  • FIG. 4 is a conceptual diagram showing the structure of an optical system when a transmissive liquid crystal display is used as the spatial light modulator 120 in the optical system according to an embodiment of the present invention.
  • the specific structure and operation of the transmissive liquid crystal display will be dealt with in detail in Fig. 8 and the related description.
  • the light source 110 is disposed in front of the spatial light modulator 120 in a coaxial or straight line with the spatial light modulator 120 in an optical path. Accordingly, the light emitted from the light source 110 passes through the spatial light modulator 120.
  • the light source 110 is arranged coaxially or in a straight line with the spatial light modulator 120, and only a transmissive liquid crystal display is given as an example, but the spatial light modulator 120 of another method may be used in a similar manner or in a different manner. , All such modifications are included in the scope of the present invention.
  • FIGS. 2 to 4 only a specific combination of the light source 110 and the spatial light modulator 120 is shown in FIGS. 2 to 4, but the present invention is not limited to a specific combination method of both devices.
  • the present invention can be implemented for any spatial light modulator 120.
  • a structure and operation method of an exemplary spatial light modulator 120 usable in the present invention will be described.
  • FIG. 5 and 6 illustrate a digital optical projector that is an example of a spatial light modulator 120 of an optical system according to an embodiment of the present invention, and a digital micromirror device (DMD) that is an element constituting the digital light projector. It is a conceptual diagram.
  • the digital optical projector shown in FIG. 5 is a digital micromirror device arranged in an array, and the digital micromirror device is a micro-sized mirror made of a micro electro-mechanical system (MEMS). . That is, in a digital light projector, each digital micromirror device serves as a pixel.
  • the digital micromirror device constitutes an array of 1024 columns and 768 rows, but the number of columns and rows constituting the array is exemplary, and may have any other number of columns and rows.
  • the digital light projector according to an embodiment of the present invention may be implemented through an arbitrary device, for example, a digital light projector manufactured by Texas Instruments.
  • two digital micromirror devices 120 are shown. There is an electrode under the digital micromirror device 120 to receive an electrical signal from the outside, and a reflector is provided at the top to reflect light. When an electric signal is applied to the lower electrode, the hinge supporting the upper reflector is bent, and the angle of the reflector is adjusted.
  • Light 121 from the outside is reflected by the projection lens 122 and emitted to the outside according to the angle of the reflector 120 of the digital micrometer device, or is reflected by the light absorption plate 123 and is absorbed without being emitted to the outside. do.
  • the digital micromirror device shown on the right reflects the light 121 to the projection lens 122
  • the digital micromirror device shown on the left reflects the light 121 to the light absorbing plate 123.
  • the pixels corresponding to the digital micromirror device shown on the right appear to be in the on state to emit light
  • the pixels corresponding to the digital micromirror device shown on the left do not emit light. It appears to be in the off state.
  • an electric signal using an electric circuit connected to the lower electrode of each digital micromirror device, it is possible to turn on/off the light of the individual digital micromirror device.
  • the hinge angle when the signal is on, the hinge angle is adjusted to direct light to the projection lens 122, and when the signal is off, the hinge angle can be adjusted so that the light is reflected to the light absorbing plate 123. have. Turning on and off of the electric signal and light may be made to correspond to the opposite, and all such variations are within the scope of the present invention.
  • each pixel of the digital light projector can be turned on/off by a signal from the outside using, for example, a computer, so that a light source having a desired shape, such as a circle, a square, or even a text or picture, can be used. It can be generated, and by controlling this signal at a constant refresh rate based on predetermined data, a light source corresponding to a moving picture can be created.
  • the LCoS type microdisplay is similar to the digital optical projector shown in FIG. 5 in that individual elements are arranged in an array, but the individual elements are not a digital micromirror device but an LCoS element. That is, in the LCoS microdisplay, the LCoS device serves as a pixel.
  • FIG. 7 is a conceptual diagram showing a single device (hereinafter referred to as an “LCoS device”) of an LCoS type microdisplay that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
  • an LCoS device a single device of an LCoS type microdisplay that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
  • the LCoS device shown in FIG. 7 is substantially similar to a single device of a known liquid crystal display (LCD) in terms of its structure, but differs somewhat in that it is formed on a silicon substrate instead of a glass substrate.
  • a CMOS element 127 is disposed on the silicon substrate, a reflective film, a liquid crystal 126, an alignment film, a transparent electrode 125, and a glass plate to protect the liquid crystal from physical damage from the outside are disposed on the silicon substrate.
  • the polarizing plate 124 is disposed obliquely in consideration of the angle of incident light from.
  • FIG. 8 is a conceptual diagram showing a single element (hereinafter referred to as a'transmissive LC cell') of a transmissive liquid crystal display that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
  • the transmissive LC cell shown in FIG. 8 has a structure similar to a cell of a liquid crystal display known in the art, and is presented in a simplified form by omitting some structures such as transparent electrodes for description. Compared with the LCoS device of FIG. 7, it can be recognized that both sides are made of glass.
  • a liquid crystal 129 is disposed between both glass plates 128 (more generally, a material capable of transmitting light other than glass) And a voltage source V(t) is connected between the liquid crystals.
  • the liquid crystal 129 when no voltage is applied to the transmissive LC cell, the liquid crystal 129 is arranged in a disordered direction, whereas when a voltage is applied in Fig. 8(b), the liquid crystal 129 is in the same direction.
  • the liquid crystal 129 may or may not be aligned depending on whether a voltage is applied, and may or may not transmit light depending on the alignment state. Therefore, each transmissive LC cell can be turned on/off by applying or not applying a voltage to each transmissive LC cell.
  • the spatial light modulator 120 has been described as being a separate element separated from the polarization state generator.
  • the polarization state generator 120 is depicted as a separate device separated from the devices 130a to 130d corresponding to the polarization state generator.
  • the spatial light modulator 120 may perform part or all of the function of changing the polarization state by itself according to its structure.
  • polarization state generator 120 may combine an element that plays the role of such a polarization state generator with a single element of the polarization state generator 120, or combines an element that plays the role of a polarization state generator integrally with the entire device of the polarization state generator 120. It can be envisioned, and all of these configurations are included in the scope of the present invention.
  • FIG. 9 is a conceptual diagram showing that the color and polarization state of the liquid crystal transmits differently according to the voltage applied to the transmissive LC cell, which is a single element of a transmissive liquid crystal display, which is an example of a spatial light modulator of an optical system according to an embodiment of the present invention. .
  • polarizing plates are added to the left and right (arrows indicate polarization directions).
  • the light incident from the left passes through the left polarizing plate, only the polarized light passes through, and the polarization state changes through the liquid crystal, and only the light of the polarization direction component determined by the right polarizing plate passes through the right polarizing plate and leaves the device. do.
  • Light incident from the left passes through the left polarizing plate and only the light of the polarized component passes. This light is incident on the liquid crystal, but because the liquid crystal is not aligned, it passes through the liquid crystal without changing the polarization direction.
  • the light passing through the liquid crystal reaches the right polarizing plate, and the right polarizing plate has a polarization direction perpendicular to the left polarizing plate. For example, when the polarization direction of the left polarizing plate is 45 degrees, the polarization direction of the right polarizing plate is 135 degrees.
  • the light reaching the right polarizing plate has a polarization direction perpendicular to the right polarizing plate, it cannot pass through the right polarizing plate. As a result, when viewed from the outside, this pixel does not emit light, so it appears black, and the pixel is turned off.
  • FIG. 9B to 9E illustrate a state in which a voltage is applied to the liquid crystal and the liquid crystal is aligned as the applied voltage increases.
  • the strength of the applied voltage may have a continuous value, and the liquid crystal may have not only completely aligned or completely aligned states, but also continuous intermediate states.
  • the degree to which the polarization state of the light passing through the left polarizing plate and incident on the liquid crystal is changed by the liquid crystal increases.
  • Fig. 9(e) in which the liquid crystals are completely aligned, the polarization direction rotates 90 degrees while the light incident from the left passes through the liquid crystal. As a result, the polarization direction coincides with the polarization direction of the right polarizing plate.
  • the liquid crystal is phase modulated.
  • the spatial light modulator 120 has an element that performs spatial light modulation in a different way instead of a liquid crystal, and a phase modulator exists at the beginning of the polarization state generator separated from the spatial light modulator 120. Will have. That is, due to the liquid crystal of the spatial light modulator 120, the spatial light modulator 120 plays a part of the polarization state generator.
  • the spatial light modulator 120 performs some or all of the functions of the polarization state generator. It should be understood as what can be done.
  • FIGS. 10 and 11 are conceptual diagrams for explaining characteristics of a rear focal plane 200 in an optical system according to an embodiment of the present invention.
  • FIG. 10 is for explaining that light incident on the rear focal plane 200 at the same point is incident on the sample 300 at the same angle.
  • the rear focal plane 200 of FIG. 2 the objective lens 150 (indicated by being simplified with lines for convenience of explanation), and the sample 300 are shown.
  • Three light paths are shown at points A and B on the optical path, respectively.
  • the solid lines from A and B indicate the left point of the rear focal plane 200, and the broken line indicates the center point of the rear focal plane 200.
  • the double-dashed line is passing through the right point of the rear focal plane 200.
  • the light rays (solid line) passing through the left side of the rear focal plane 200 at points A and B are incident at an angle of ⁇ from the left when entering the sample 300 through the objective lens 150, and the rear focus
  • the light ray (dashed line) passing through the center of the plane 200 is vertically incident on the sample 300 through the objective lens 150, and the light ray (double-dotted line) passing through the right side of the rear focal plane 200 is the objective.
  • the incident is incident at an angle of ⁇ from the right.
  • the light rays passing through the left side of the rear focal plane 200 (solid line) and the light rays passing through the right side of the rear focal plane 200 (dashed-dotted line) are from the central axis of the objective lens 150 at the rear focal plane 200. It passes through a point separated by an equidistant distance, and as a result, it can be seen that the incident angle to the sample 300 is the same.
  • the light rays passing through the same point of the rear focal plane 200 are incident on the specimen 300 at the same angle, and this angle is determined according to the distance from the central axis of the objective lens 150.
  • FIG. 11 is for explaining that even light from another point on the specimen 300 meets at a point on the rear focal plane 200. This principle can be seen by reversing the path of the light beam in FIG. 10.
  • FIG. 11 a sample 300, an objective lens 150 (simplified and indicated by lines for convenience of explanation), and a rear focal plane 200 are shown.
  • the light from different points A and B on the sample 300 rises to the left at the same angle (solid line), rises vertically (dashed line), or rises to the right (double-dotted line), and the starting point from sample 300 Despite this difference, since the angles were the same, they meet at the same points on the rear focal plane 200, that is, a, b, and c, respectively.
  • 12 and 13 are conceptual diagrams for explaining a relationship between incident light and reflected light in an optical system of an optical system according to an embodiment of the present invention.
  • the rear focal plane 200, the objective lens 150, and the sample 300 are shown.
  • the sample 300 is located at a point separated by the focal length f of the objective lens 150.
  • a light ray (solid line, broken line) passing through the rear focal plane 200 passes through the objective lens 150 and enters the sample 300. You can see the same point.
  • the light rays passing through the same point of the rear focal plane 200 are incident on the sample 300 at the same angle, and when the radial distance from the central axis of the objective lens 150 is the same, that is, the broken lines on the left and right sides in FIG. , Or in the case of the left and right solid lines, the value of the incident angle is the same.
  • FIG. 13 is a conceptual diagram illustrating a correlation between incident light incident on each point on the rear focal plane 200 in a polar coordinate system centered on the central axis of the objective lens 150 and reflected light accordingly.
  • Incident light by the optical system according to an embodiment of the present invention all have the same polarization before incidence of the objective lens 150 and the sample 300, for example, polarization in the x-axis direction in this example (solid line).
  • each incident light is an angle in the polar coordinate system centered on the central axis of the objective lens 150 ( ), the direction of the incident surface is different (dashed lines between 1 and 1', 2 and 2', 3 and 3', and 4 and 4', respectively), and the components of p polarization and s polarization As a result, the polarization component of the reflected light is also different.
  • the incident light 1 passes through the objective lens 150 and enters the specimen 300 in a path curved in the -x-axis direction, and as a result, the incident surface (broken line between 1 and 1') becomes parallel to the polarization direction.
  • the polarization of the reflected light comes out with the same polarization direction as the polarization direction of the incident light (1').
  • the incident light 3 passes through the objective lens 150 and enters the specimen 300 in a path curved in the -y axis direction, and as a result, the incident surface (broken line between 3 and 3') becomes completely perpendicular to the polarization direction. , it means that there is only s polarization, and the reflected light comes out without mixing the p polarization component (regardless of the phase change) (3').
  • the position on the rear focal plane 200 is the radius (r) and the angle (r) on the polar coordinate system with the central axis of the objective lens 150 as the origin.
  • angle ( ) it is possible to adjust the components of the p-polarized light and the s-polarized light incident on the sample 300, and by adjusting the radius r, the angle of incidence ( ⁇ ) incident on the sample 300 can be adjusted.
  • 14 to 17 are conceptual diagrams for explaining a method of measuring physical properties by adjusting a position to be illuminated on the rear focal plane 200 by the spatial light modulator 120 in an optical system according to an embodiment of the present invention. .
  • the coordinate plane of FIG. 14 represents a position on the rear focal plane 200.
  • the spatial light modulator 120 it is possible to enter the incident light only at a specific point on the rear focal plane 200 by using the spatial light modulator 120.
  • the size of a specific point may vary depending on the number of pixels and the area per pixel of the spatial light modulator 120, and the spatial light modulator 120 in which a larger number of pixels are integrated, that is, a higher resolution, is narrower.
  • the incident light can pass only at more precise points.
  • the radius is fixed to r 1 on the polar coordinate system of the rear focal plane 200, and the angle ( The incident light is irradiated while varying) from 0 to 360 degrees, and the reflected light accordingly is measured (path 1).
  • the incident angle of the incident light irradiated to the sample 300 is fixed accordingly, and a value at which the polarization component changes as the angle changes is incident on the sample 300.
  • the method of adjusting the angle can be measured continuously from 0 to 360 degrees, or discretely measured for specific angles such as 0, 45, and 90 degrees, and the measurement direction is also the direction in which the angle increases (counterclockwise ) (Fig. 14) or in a decreasing direction (clockwise) (Fig. 15).
  • the interval between the change value and the measured angle may vary depending on the resolution of the spatial light modulator 120.
  • the change value may be a value in which the radius increases or decreases, and the change value itself may vary according to the radius.
  • the radius can increase gradually, such as 1 -> 2 -> 3 -> 4, or it can decrease to 4 -> 3 -> 2 -> 1, and change like 10 -> 15 -> 18 -> 20 However, the increase may decrease or vice versa.
  • the measurement of the reflected light as described above may be exemplarily implemented through the following sequence: For a polar coordinate system whose origin is the lens center axis in the back focal plane of the objective lens, a radius value is set.
  • the primary variable and the angular (radian) value are set as secondary variables, the secondary variable is changed from 0 to 360 degrees, and the primary variable is changed at a predetermined value for each cycle of change of the secondary variable.
  • the angle ( ) Is fixed and the radius (r) is changed.
  • the measurement of the reflected light as described above can be implemented through the following sequence: For a polar coordinate system with the lens center axis as the origin at the rear focal plane of the objective lens, the angle value is the primary variable and the radius value is the secondary variable. And changing a secondary variable by a change value determined according to the resolution of the spatial light modulator at a predetermined value, and changing the primary variable from 0 degrees to 360 degrees for each change cycle of each secondary variable.
  • a measurement can be performed using another sequence. I can.
  • each pixel is arranged in a row-column order, that is, A sequence can be configured in a continuous manner, such as from column 1 to the last column of row 1, column 1 to last column of row 2, ... (FIG. 17).
  • the last column and the last row may be determined according to the horizontal and vertical resolution of the array of pixels constituting the spatial light modulator 120.
  • the direction of sweeping each row-column may be different.
  • a sequence may be formed in a form that continues from the last row to the first row and/or from the last column to the first column.
  • the measurement of reflected light according to the above method can be implemented through the following sequence: For a Cartesian coordinate system whose origin is the central axis of the objective lens at the rear focal plane of the objective lens, the row is the primary variable, With a column as a secondary variable, a secondary variable is changed between the number of columns of the array of one or more pixels in column 1, and the primary variable is an array of the one or more pixels in row 1 for each change cycle of the secondary variable A sequence that changes between the number of rows of.
  • This alternative sequence may be, for example, a sequence from the top left to the bottom right while drawing a horizontal line, similar to the scanning of an electron gun of a CRT TV, and the same sequence as the control signal of each pixel of the spatial light modulator 120 is input. Because it can, there is an advantage that the coding of the sequence is simpler. However, compared to the sequence according to the polar coordinate system, the order of each measurement value, the incident angle, and the polarization state are mixed without being correlated. Therefore, after the measurement, it is necessary to rearrange the data according to the incident angle and the polarization state.
  • the optical system in order to change the polarization component of incident light, at least one optical element on the polarization state generator or the polarization state analyzer has to be manually or mechanically moved. Compared with the conventional technology, it has an advantage that the optical system can be operated without generating physical vibration. Although there may be a mechanical movement of the pixels included in the spatial light modulator 120, the vibration caused by this is substantially small to a level that is difficult to detect. Therefore, noise due to vibration is reduced and the reliability of the measured value is improved.
  • Another advantage of the method for measuring physical properties by an optical system according to an embodiment of the present invention is that the on/off of a specific pixel in the spatial light modulator 120 described above is performed in a virtually automated sequence through an electronic device such as a computer connected to the outside. Because of this, faster and more convenient measurements are possible compared to previous manual or mechanical operation. That is, the movement of the position of light on the above-described rear focal plane 200 can be automated by a computer simply by coding a sequence specifying a pixel to be turned on by the spatial light modulator 120, and this sequence is preprogrammed. You can also use the old one. Therefore, the need for direct manipulation by the user is significantly reduced.
  • the optical system using the spatial light modulator according to the present invention When the optical system using the spatial light modulator according to the present invention is used, it is possible to measure the physical properties of a sample without driving a motor, and since the possibility of interference of noise due to mechanical manipulation is reduced, more accurate and fast measurement is possible.
  • the advantages of the conventional elliptical polarization microscope that is, the advantages of high lateral resolution and high resolution imaging are maintained in the optical system according to the present invention.

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Abstract

Provided is an optical system for measuring the physical properties of a sample, comprising: a spatial light modulator for modulating, into light in the predefined shape of a first image, a beam cross-section of light received from a light source; a polarization state generator, which receives the light modulated by the spatial light modulator so as to change same to a predefined first polarization state; an object lens which receives the light changed to the first polarization state so as to cause same to be incident on the sample, and which receives light reflected from the sample; a polarization state analyzer, which receives the light reflected from the sample so as to be received by the object lens, and thus pass through the object lens, so as to change same to a predefined second polarization state; and a photodetector, which receives the light changed to the second polarization state so as to convert same into an electrical signal.

Description

공간 광 변조기를 이용한 광학계 및 이를 이용한 물성 측정 방법 Optical system using spatial light modulator and method for measuring properties using the same
본 발명은 공간 광 변조기를 이용한 광학계 및 이를 이용한 시료의 물성 측정에 관한 것이다.The present invention relates to an optical system using a spatial light modulator and to measurement of physical properties of a sample using the same.
타원계측법(ellipsometry)은 빛의 편광 특성 변화를 이용하여 시료의 물성을 측정하는 방법이다. 타원계측법을 이용한 측정 장비를 타원계(ellipsometer)라고 하는데, 입사광을 원하는 형태로 편광시켜 시료에 입사시킨 후, 시료에서 반사(반사형 타원계) 또는 투과(투과형 타원계)되는 빛의 편광 상태를 측정하여 복소 굴절률, 유전함수, 전기 전도도, 격자 구조와 같은 결정상태와 같은 물성을 측정하는 것이다.Ellipsometry is a method of measuring the physical properties of a sample by using the change in polarization characteristics of light. The measuring equipment using the ellipsometry method is called an ellipsometer. After the incident light is polarized into a desired shape and incident on the sample, the polarization state of light reflected from the sample (reflective ellipsometer) or transmitted (transmitted ellipsometer) is measured. It measures physical properties such as complex refractive index, dielectric function, electrical conductivity, and crystal state such as lattice structure.
예컨대 반사형 타원계는 다중층 박막의 두께를 측정하는데 사용될 수 있는데, 다른 방식의 박막 두께 측정 방식에 비해 비접촉-비파괴 방식이라는 점, 투명한 재질이나 유전체 박막에도 적용가능하다는 점, 분해능이 뛰어나다는 점에서 각광받으며, 디스플레이 및 반도체 산업에서 널리 쓰이고 있다.For example, a reflective ellipsometer can be used to measure the thickness of a multilayer thin film. Compared to other thin film thickness measurement methods, it is a non-contact-non-destructive method, is applicable to transparent materials or dielectric thin films, and has excellent resolution. In the spotlight, it is widely used in the display and semiconductor industries.
그러나 일반적인 타원계는 일정한 경사를 가지고 한 지점에만 빛을 조사하기 때문에 측면 해상도(lateral resolution)가 떨어져 이미징(imaging)이 어렵고, 좁은 영역이나 미세 패턴에서 원하는 부위의 해석을 하기가 어렵다는 단점이 있었다. 이를 극복하기 위해 광감지기 단에 카메라에 사용되는 CCD 어레이(CCD array) 등을 배치하여 샘플을 이미징하는 방법이 시도되었으나, 타원계의 경사 구조로 인해 측면 해상도를 높이는 데에는 한계가 있었다.However, since a general ellipsometer irradiates light only at one point with a certain inclination, imaging is difficult due to low lateral resolution, and it is difficult to analyze a desired area in a narrow area or fine pattern. To overcome this, a method of imaging a sample by placing a CCD array used for a camera at the stage of a photodetector has been attempted, but there is a limit to increasing the lateral resolution due to the inclined structure of the ellipsometer.
한편, 2000년 K. R. Neumaier에 의해 소개된 타원편광 현미경(Ellipsometric Microscope)은 수직 현미경 구조를 도입하여 고배율의 이미징을 가능케 하였지만, 편광 상태 조절을 위해 광학 소자(optical component)를 물리적으로(수동으로 또는 적어도 기계적으로) 조절해 주어야 한다는 점에서 한계가 있었다. 다시 말해, 타원편광 현미경을 사용하기 위해서는 예컨대 편광자(polarizer)의 위치를 조절해주거나 현미경 내에서 미세하게 움직이는 거울을 배치하여야 하고, 이러한 광학 소자의 물리적 움직임은 그 자체로 진동을 유발하여 잡음(noise)을 발생시킬 뿐만 아니라, 극도로 민감하게 유지되는 광학 소자 간의 광학적 정렬(optical alignment)을 깨트릴 위험이 있다는 점에서 문제가 된다. 작업자는 각 측정 이후 다음 측정을 재개하기 전까지 잡음을 제거하고 광학적 정렬 상태를 회복하기 위하여 상당한 시간을 허비하여야 되며, 각 측정마다 신뢰성이 확보되기 어렵다. 이 때문에 타원편광 현미경은 현재까지도 널리 쓰이지 못하고 있다.Meanwhile, the Ellipsometric Microscope, introduced by KR Neumaier in 2000, introduced a vertical microscope structure to enable high-magnification imaging, but the optical component was physically (manually or at least) to adjust the polarization state. There was a limit in that it had to be adjusted mechanically. In other words, in order to use an elliptical polarization microscope, for example, a position of a polarizer must be adjusted or a mirror that moves finely within the microscope must be arranged, and the physical movement of such an optical element itself causes vibration to cause noise. This is problematic in that there is a risk of breaking the optical alignment between optical elements, which are kept extremely sensitive, as well as to generate ). After each measurement, the operator has to spend a considerable amount of time to remove noise and restore optical alignment after each measurement, and it is difficult to secure reliability for each measurement. For this reason, elliptical polarization microscopes are not widely used until now.
따라서 종래의 타원계 및 타원편광 현미경의 단점을 극복하는, 즉, 높은 측면 해상도를 확보하면서도 물리적 진동을 유발하지 않는 광학계의 개발이 요구된다.Therefore, it is required to develop an optical system that overcomes the disadvantages of the conventional ellipsometer and elliptical polarization microscope, that is, does not induce physical vibration while securing high lateral resolution.
본 발명은 공간 광 변조기를 이용한 광학계 및 이를 이용한 물성 측정 방법을 제공하는 것을 목적으로 한다.An object of the present invention is to provide an optical system using a spatial light modulator and a method for measuring physical properties using the same.
본 발명에 따르면 위와 같은 목적은 후술될 청구범위의 특징을 포함하는 광학계 및 물성을 측정하는 방법으로써 달성될 수 있다.According to the present invention, the above object can be achieved by a method of measuring an optical system and physical properties including the features of the claims to be described later.
본 명세서에 설명된 실시예들에 의해 제공되는 이들 및 추가적인 특징들은 도면들과 관련하여 이하의 상세한 설명의 관점에서 보다 완전히 이해될 것이다.These and additional features provided by the embodiments described herein will be more fully understood in view of the following detailed description in connection with the drawings.
본 발명에 따른 공간 광 변조기를 이용한 광학계를 사용하면 모터의 구동없이 자동화된 시료의 물성 측정을 할 수 있으며, 기계적 조작으로 인한 노이즈의 개입 가능성이 감소되기 때문에 더 정확하고 빠른 측정이 가능해진다. 또한 종래의 타원편광 현미경이 가졌던 장점, 즉 높은 측면 해상도와 고해상도 이미징이 가능하다는 장점은 본 발명에 따른 광학계에서도 그대로 유지된다.When the optical system using the spatial light modulator according to the present invention is used, it is possible to measure the physical properties of a sample without driving a motor, and since the possibility of interference of noise due to mechanical manipulation is reduced, more accurate and fast measurement is possible. In addition, the advantages of the conventional elliptical polarization microscope, that is, the advantages of high lateral resolution and high resolution imaging are maintained in the optical system according to the present invention.
도면들에 개시된 실시예들은 본질적으로 설명적이고 예시적인 것이며 본 발명을 한정하려는 의도가 아니다. 이하의 설명적인 예시들의 상세한 설명은 이하의 도면들과 함께 읽혀질 때 이해될 수 있다.The embodiments disclosed in the drawings are illustrative and illustrative in nature and are not intended to limit the invention. The detailed description of the following illustrative examples may be understood when read in conjunction with the following drawings.
도 1은 종래 기술에 의한 타원계의 기본적인 구조를 도시한 개념도이다.1 is a conceptual diagram showing the basic structure of an elliptic system according to the prior art.
도 2는 본 발명의 일 실시예에 의한 광학계의 일반적인 구조, 즉 광학 소자의 배치 및 광 경로를 도시한 개념도이다.2 is a conceptual diagram illustrating a general structure of an optical system, that is, an arrangement of optical elements and an optical path according to an embodiment of the present invention.
도 3은 본 발명의 일 실시예에 따른 광학계에서 공간 광 변조기로 디지털 광 프로젝터 또는 LCoS 방식의 마이크로디스플레이를 사용한 경우의 광학계의 구조를 도시한 개념도이다.3 is a conceptual diagram showing the structure of an optical system when a digital light projector or an LCoS microdisplay is used as a spatial light modulator in the optical system according to an embodiment of the present invention.
도 4는 본 발명의 일 실시예에 따른 광학계에서 공간 광 변조기로 투과형 액정 디스플레이를 사용한 경우의 광학계의 구조를 도시한 개념도이다.4 is a conceptual diagram showing a structure of an optical system when a transmission type liquid crystal display is used as a spatial light modulator in the optical system according to an embodiment of the present invention.
도 5 및 도 6은 본 발명의 일 실시예에 의한 광학계의 공간 광 변조기의 예시인 디지털 광 프로젝터 및 디지털 광 프로젝터를 구성하는 소자인 디지털 마이크로미러 장치를 도시한 개념도이다.5 and 6 are conceptual diagrams illustrating a digital light projector that is an example of a spatial light modulator of an optical system and a digital micromirror device that is an element constituting the digital light projector according to an embodiment of the present invention.
도 7은 본 발명의 일실시예에 의한 광학계의 공간 광 변조기의 예시인 LCoS 방식의 마이크로디스플레이의 단일 소자를 도시한 개념도이다. 7 is a conceptual diagram showing a single device of an LCoS type microdisplay that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
도 8은 본 발명의 일 실시예에 의한 광학계의 공간 광 변조기의 예시인 투과형 액정 디스플레이의 단일 소자를 도시한 개념도이다.8 is a conceptual diagram showing a single element of a transmission type liquid crystal display that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
도 9는 본 발명의 일 실시예에 의한 광학계의 공간 광 변조기의 예시인 투과형 액정 디스플레이의 단일 소자인 투과형 LC 셀에 인가되는 전압에 따라 액정이 투과시키는 색상 및 편광 상태가 달라지는 것을 도시한 개념도이다.FIG. 9 is a conceptual diagram showing that the color and polarization state of the liquid crystal transmits differently according to the voltage applied to the transmissive LC cell, which is a single element of a transmissive liquid crystal display, which is an example of a spatial light modulator of an optical system according to an embodiment of the present invention. .
도 10과 도 11은 본 발명의 일 실시예에 의한 광학계에서 후방 초점 면의 특성을 설명하기 위한 개념도이다.10 and 11 are conceptual diagrams for explaining characteristics of a rear focal plane in an optical system according to an embodiment of the present invention.
도 12와 도 13은 본 발명의 일 실시예에 의한 광학계의 광학계에서 입사광과 반사광의 관계를 설명하기 위한 개념도이다.12 and 13 are conceptual diagrams for explaining a relationship between incident light and reflected light in an optical system of an optical system according to an embodiment of the present invention.
도 14 내지 도 17은 본 발명의 일 실시예에 따른 광학계에서, 공간 광 변조기에 의해 후방 초점 면 상에서 조광되는 위치를 조절하여 물성 측정을 수행하는 방법을 설명하기 위한 개념도이다.14 to 17 are conceptual diagrams for explaining a method of measuring physical properties by adjusting a position to be illuminated on a rear focal plane by a spatial light modulator in an optical system according to an exemplary embodiment of the present invention.
본 발명은 다양한 변경을 가질 수 있고 여러가지 형태를 가질 수 있는 바, 본 발명의 실시예들을 여기에서 상세하게 설명할 것이다. 그러나 이는 본 발명을 특정한 개시 형태로 한정하려는 것이 아니며, 본 발명의 사상 및 기술범위에 포함되는 모든 변경, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다.Since the present invention can have various modifications and various forms, embodiments of the present invention will be described in detail herein. However, this is not intended to limit the present invention to a specific form of disclosure, it should be understood to include all changes, equivalents, or substitutes included in the spirit and scope of the present invention.
상기 용어들은 하나의 구성요소들을 다른 구성요소로부터 구별하는 목적으로 사용된다. 본 출원에서 사용한 용어는 단지 특정한 실시예를 설명하기 위해 사용된 것이며, 본 발명을 한정하려는 의도가 아니다. 단수의 표현은 문맥상 명백하게 다른 뜻을 가진 것이 아닌 한, 복수의 표현을 포함한다.The terms are used for the purpose of distinguishing one component from another component. The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly has a different meaning.
본 발명에서 "포함한다", "가진다" 또는 "이루어진다" 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것이 존재함을 지칭하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부분품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.In the present invention, terms such as "comprise", "have" or "consist of" are intended to refer to the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification. It is to be understood that the above other features, or the possibility of the presence or addition of numbers, steps, actions, components, parts, or combinations thereof, are not excluded in advance.
다르게 정의되지 않는 한, 기술적이거나 과학적인 용어를 포함해서 여기서 사용되는 모든 용어들은 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에 의해 일반적으로 이해되는 것과 동일한 의미를 가지고 있다. 일반적으로 사용되는 사전에 정의되어 있는 것과 같은 용어들은 관련 기술의 문맥상 가지는 의미와 일치하는 의미를 가지는 것으로 해석되어야 하며, 본 출원에서 명백하게 정의하지 않는 한, 이상적이거나 과도하게 형식적인 의미로 해석되지 않는다.Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.
이하, 첨부한 도면들을 참조하여, 본 발명의 바람직한 실시예를 보다 상세하게 설명하고자 한다.Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.
1. 타원계의 원리 (도 1)1. Principle of the elliptic system (Fig. 1)
도 1은 종래 기술에 의한 타원계의 기본적인 구조를 도시한 개념도이다. 좌측의 광원(light source)은 입사광을 생성하여 방출하는 역할을 하며, LED나 레이저 기타 알려진 형태의 강도와 파장을 가진 다양한 광원이 사용될 수 있다.1 is a conceptual diagram showing the basic structure of an elliptic system according to the prior art. The light source on the left serves to generate and emit incident light, and various light sources having an intensity and wavelength of an LED, laser or other known type may be used.
방출된 입사광은 편광상태생성기(polarization state generator, PSG)를 통과하면서 원하는 형태의 편광 상태를 가지게 된다. 편광상태생성기는 하나 또는 그 이상의 다양한 광학 소자로 이루어질 수 있는데, 예컨대 편광자(polarizer), 보상기(compensator, 지연기(retarder)로도 불림), 위상변조기(phase modulator) 등이 그것이다. 이러한 광학 소자들 및 그들이 하는 역할은 당업자에게 잘 알려져 있다. 전기 소자와 마찬가지로, 이러한 광학 소자들을 조합하여 입사광이 원하는 편광상태(선형 편광, 원형 편광, 타원 편광)를 가지도록 조절 가능하다.The emitted incident light passes through a polarization state generator (PSG) to have a desired polarization state. The polarization state generator may consist of one or more various optical elements, such as a polarizer, a compensator, also called a retarder, and a phase modulator. These optical elements and their role are well known to those skilled in the art. Like electric devices, it is possible to adjust the incident light to have a desired polarization state (linear polarization, circular polarization, elliptical polarization) by combining these optical devices.
편광상태생성기를 통과한 입사광은 일정한 각도(θi)를 가지고 시료 표면에 입사된다. 입사광(incident light)은 시료 표면에서 시료를 투과하는 투과광(transmissive light)과 시료에서 반사되는 반사광(reflected light)으로 나뉘는데, 투과광은 입사광이 지나온 매질과 시료의 굴절률 등에 따라 특정한 각도로 휘게 되고, 반사광은 입사광과 동일한 각도(θr)로 반사된다. 즉, θi = θr이다. 여기서 입사광과 반사광에 의해 결정되는, 시료에 수직인 면을 입사면(plane of incidence)이라고 한다. 반사광은 시료 표면에서 바로 반사된 빛 뿐만 아니라, 전술한 투과광이 시료 내부로 진행하다가 시료 하단에 배치된 다른 매질과의 표면에서 반사된 후 상부의 시료 표면을 투과한 빛, 또는 시료 표면에서 다시 한 번 아래쪽으로 반사되어 하단으로 진행하다가 하단의 다른 매질과의 표면에서 재차 반사되어 상부의 시료 표면을 투과한 빛 등이 중첩된 형태가 된다.The incident light passing through the polarization state generator is incident on the surface of the sample with a certain angle (θ i ). Incident light is divided into transmissive light that passes through the sample from the sample surface and reflected light that is reflected from the sample. The transmitted light is bent at a specific angle depending on the medium through which the incident light passes and the refractive index of the sample. Is reflected at the same angle (θ r ) as the incident light. That is, θ i = θ r . Here, the plane perpendicular to the sample determined by incident light and reflected light is called a plane of incidence. Reflected light is not only the light directly reflected from the sample surface, but also the light transmitted through the upper sample surface after the above-described transmitted light travels inside the sample and is reflected from the surface with another medium disposed at the bottom of the sample, or It is reflected downwards, proceeds to the bottom, and is reflected again from the surface of the other medium at the bottom to form an overlapping form of light transmitted through the upper sample surface.
반사광은 편광상태생성기에서 조절된 입사광과는 다른 상태를 가지게 되므로, 그 상태를 분석하기 위하여 반사광의 경로 상에 편광상태분석기(polarized state analyzer, PSA)를 두어, 예컨대 특정 편광 성분의 빛만을 추출하여 그 강도 등을 측정함으로써 반사광의 상태를 알아낼 수 있다.Since the reflected light has a different state from the incident light controlled by the polarization state generator, a polarized state analyzer (PSA) is placed on the path of the reflected light to analyze the state, for example, by extracting only light of a specific polarization component. By measuring the intensity or the like, the state of the reflected light can be determined.
반사광의 경로의 마지막에 있는 광감지기(photodetector)는 빛의 세기를 측정하여 전기신호로 변환한다. 광감지기는 광다이오드, CCD 등일 수 있으며, 일반적으로 빛의 성분이나 위상 등을 측정하지는 못하고 세기(intensity)만 측정할 뿐이지만, 편광상태분석기를 조절하여, 예컨대 편광상태분석기 내에 포함된 편광기를 회전시킴으로써, 특정 편광 상태의 빛 만을 통과하도록 하고 각 편광 상태에 따른 빛의 세기를 감지함으로써 빛의 편광 상태까지 계산해 낼 수 있다. 또 이하에서 보듯이 편광상태분석기 대신 편광상태생성기에서 그 안에 포함된 편광기를 회전시킴으로써 시료에 입사하는 입사광을 조절하는 방식으로 빛의 편광 상태를 계산해 낼 수도 있다.A photodetector at the end of the path of reflected light measures the intensity of light and converts it into an electrical signal. The photodetector may be a photodiode, a CCD, etc., and generally cannot measure the component or phase of light, but only measure the intensity, but by adjusting the polarization state analyzer, for example, rotating the polarizer included in the polarization state analyzer. By doing so, it is possible to calculate the polarization state of light by allowing only light of a specific polarization state to pass through and sensing the intensity of light according to each polarization state. In addition, as shown below, the polarization state of light may be calculated by adjusting the incident light incident on the sample by rotating the polarizer included in the polarization state generator instead of the polarization state analyzer.
이하에서는 존스 행렬(Jones Matrix)을 이용하여 전술한 타원계에 의한 편광 상태의 변화를 설명할 것이다. 이 방법에서 빛의 상태 벡터는 1×2 행렬의 형태를 가지는데, 관행적으로 행렬의 제1행 성분은 p 편광, 즉 자기장의 진동방향이 입사면에 수직인 TM 모드(transverse magnetic mode)를, 제2행 성분은 s 편광, 즉 전기장의 진동방향이 입사면에 수직인 TE 모드(transverse electric mode)를 의미한다. p 편광과 s 편광 성분은 서로 수직이다. 존스 행렬의 표기에 따르면, p 편광된 빛은
Figure PCTKR2020006441-appb-I000001
, s 편광된 빛은
Figure PCTKR2020006441-appb-I000002
이 되며, 주어진 빛은 이 p 편광과 s 편광의 세기(intensity) 및 위상(phase)에 의해 완전하게 나타낼 수 있다.
Hereinafter, a change in the polarization state due to the above-described elliptic system will be described using a Jones matrix. In this method, the state vector of light has the form of a 1×2 matrix. Conventionally, the first row component of the matrix is p-polarized, that is, a transverse magnetic mode in which the direction of vibration of the magnetic field is perpendicular to the incident plane. , The second row component means s polarization, that is, a transverse electric mode (TE mode) in which the vibration direction of the electric field is perpendicular to the incident surface. The p-polarized and s-polarized components are perpendicular to each other. According to the Jones matrix notation, p polarized light is
Figure PCTKR2020006441-appb-I000001
, s polarized light is
Figure PCTKR2020006441-appb-I000002
And the given light can be completely represented by the intensity and phase of this p-polarized and s-polarized light.
한편 빛이 광경로 상에 지나가게 되는 광학 소자 그리고 시료는 2×2 행렬로 나타낼 수 있으며, 주어진 빛의 벡터(1×2 행렬)에 작용하는 연산자(operator)(2×2 행렬)가 된다. 예컨대, 편광기는
Figure PCTKR2020006441-appb-I000003
, 보상기는
Figure PCTKR2020006441-appb-I000004
가 되며, 시료는 (등방성 물질을 가정할 경우)
Figure PCTKR2020006441-appb-I000005
가 된다. 즉 광학 소자나 시료를 지나면서 변형된 빛의 상태는 연산자에 의해 빛의 벡터가 변형되는 작용에 비유된다. 편광상태생성기나 편광상태분석기는 위 2×2 행렬로 표현되는 광학 소자의 조합이므로, 내부에 포함된 소자에 대응하는 2×2 행렬의 곱을 구함으로서 전체가 하나의 2×2 행렬로 표현될 수도 있다.
On the other hand, optical elements and specimens through which light passes on the optical path can be represented as a 2×2 matrix, and become an operator (2×2 matrix) acting on a given vector of light (1×2 matrix). For example, the polarizer
Figure PCTKR2020006441-appb-I000003
, The compensator is
Figure PCTKR2020006441-appb-I000004
And the sample is (assuming isotropic material)
Figure PCTKR2020006441-appb-I000005
Becomes. In other words, the state of light that is deformed while passing through an optical element or sample is compared to the action of transforming the light vector by an operator. Since the polarization state generator or the polarization state analyzer is a combination of optical elements represented by the above 2×2 matrix, the whole may be expressed as a single 2×2 matrix by obtaining the product of the 2×2 matrix corresponding to the elements included therein. have.
따라서, 광원에서 나와 편광상태생성기, 시료, 편광상태분석기를 지나 감지기로 들어간 빛의 결과는 다음과 같이 표현될 수 있다.Therefore, the result of light coming out of the light source and passing through the polarization state generator, the sample, and the polarization state analyzer can be expressed as follows.
Figure PCTKR2020006441-appb-I000006
Figure PCTKR2020006441-appb-I000006
여기에서 광원(최우측의 벡터)은 논의의 편의상 p 편광만을 가진것으로 전제되었다. 실제로는 빛이 광원에서 나올 당시에는 p 편광과 s 편광 성분을 모두 가질 수 있지만, 편광상태생성기의 도입부에 편광판을 배치하여 위와 같이 특정 성분만을 지닌 상태 벡터로 변환을 할 수 있다.Here, it is assumed that the light source (the vector on the far right) has only p polarization for convenience of discussion. Actually, when light comes out of the light source, it can have both p-polarized and s-polarized components, but by placing a polarizing plate at the introduction part of the polarization state generator, it can be converted into a state vector having only a specific component as above.
이제 가장 단순한 형태의 편광상태생성기 및 편광상태분석기를 전제할 경우, 위 수식은 아래와 같이 된다.Now, assuming the simplest form of polarization state generator and polarization state analyzer, the above equation becomes as follows.
Figure PCTKR2020006441-appb-I000007
Figure PCTKR2020006441-appb-I000007
여기서, 최우측의 벡터는 광원에서 나온 빛을, 그 왼쪽의 행렬은 편광상태생성기(PSG)에 의한 변형을, 그 왼쪽의 행렬은 시료를, 그 왼쪽의 두 개의 행렬은 편광상태분석기(PSA)에 의한 변형을 나타내며, 특히 가장 왼쪽의 행렬은 편광상태분석기의 입사면을 기준으로 편광방향이 편광자의 각도(A)와 일치하는 빛 만을 통과시키는 것을 의미한다. 위 구성에서 편광상태생성기와 편광상태분석기는 편광자만으로 이루어져 있는 경우로서, 편광자의 축 각도에 해당하는 선형 편광 성분만을 남기는 기능을 하고 있으며, P와 A가 그 축 각도를 의미하는 변수이다.Here, the vector on the far right is the light from the light source, the matrix on the left is the transformation by the polarization state generator (PSG), the matrix on the left is the sample, and the two matrices on the left are the polarization state analyzer (PSA). In particular, the leftmost matrix means that only light whose polarization direction matches the angle (A) of the polarization state analyzer is passed based on the incident surface of the polarization state analyzer. In the above configuration, the polarization state generator and the polarization state analyzer are composed of only a polarizer, and have a function of leaving only a linear polarization component corresponding to the axial angle of the polarizer, and P and A are variables representing the axial angle.
rp와 rs는 물질의 다양한 물성에 대한 정보를 포함하므로, 광원, 편광상태생성기, 편광상태분석기의 설정을 조절하여 rp와 rs 값을 알아내는 것이 타원계측법의 목표가 된다.Since r p and r s contain information on various properties of a material, it is the goal of ellipsometry to find the values of r p and r s by adjusting the settings of the light source, polarization state generator, and polarization state analyzer.
한편, 전술한 바와 같이 광감지기에서는 강도(intensity)만을 얻어내므로, 얻어진 E값과 그 복소켤레값(E*)을 곱하여 강도(I(t))의 함수를 얻으면 아래와 같다.On the other hand, as described above, since the light detector obtains only the intensity, the obtained E value and the complex conjugate value (E * ) are multiplied to obtain a function of the intensity (I(t)) as follows.
Figure PCTKR2020006441-appb-I000008
Figure PCTKR2020006441-appb-I000008
Figure PCTKR2020006441-appb-I000009
Figure PCTKR2020006441-appb-I000009
즉, 광학계의 조절을 통해 강도 I(t)를 측정하면 α와 β 값을 알아낼 수 있고, α와 β 값을 알아내면 Ψ와 Δ 값을 알아낼 수 있고, Ψ와 Δ 값을 알아내면 rp와 rs의 값을 알아낼 수 있다. rp와 rs 값을 알아내면 미리 만들어진 시료의 물리 모델에 의한 예측값과 피팅하여 정합성을 판단하고, 그에 따라 모델 자체 혹은 모델의 변수값을 조절하는 재귀과정을 통해 적합한(미리 정해진 기준치 이상의 정합도를 가진) 물리 모델 및 그에 따른 시료의 물성과 특성을 계산할 수 있다.That is, if you measure the intensity I(t) through the control of the optical system, you can find out the values of α and β, find out the values of α and β, you can find out the values of Ψ and Δ, and find out the values of Ψ and Δ, you can find r p and You can find out the value of r s . When r p and r s values are found, it is fitted with the predicted values of the pre-made physical model of the sample to determine the consistency, and appropriate through the recursion process of adjusting the model itself or the variable values of the model accordingly ) And the physical model and the physical properties of the sample can be calculated accordingly.
정합도는 예컨대 예측치에 의한 수치와 실제 측정값 사이의 오차의 분산(variance) 등을 기준으로 할 수 있으며, 당업자는 다양한 방식으로 정합도를 측정하는 기준을 설정할 수 있다.The degree of matching may be based on, for example, a variance of an error between a numerical value according to a predicted value and an actual measured value, and those skilled in the art may set a standard for measuring the degree of matching in various ways.
2. 본 발명의 실시예들에 따른 광학계의 구조2. Structure of an optical system according to embodiments of the present invention
(1) 일반적인 구조 (도 2)(1) General structure (Fig. 2)
도 2는 본 발명의 일 실시예에 의한 광학계의 일반적인 구조, 즉 광학 소자의 배치 및 광 경로를 도시한 개념도이다.2 is a conceptual diagram illustrating a general structure of an optical system, that is, an arrangement of optical elements and an optical path according to an embodiment of the present invention.
광학계(100)의 좌측에는 광원(light source)(110)과 공간 광 변조기(spatial light modulator)(120)가 도시되어 있다. 본 발명에서 광원(110)과 공간 광 변조기(120)는 다양한 형태로 조합될 수 있기 때문에, 광학계의 일반적인 구조를 다루는 도 2에서는 광 경로의 도시없이 다이어그램으로 대체되어 있다. 공간 광 변조기의 종류에 따른 광학계의 구체적인 구성을 다루는 도 3 및 도 4에서는 광원(110)과 공간 광 변조기(120)가 분리된 형태로 도시될 것이다.A light source 110 and a spatial light modulator 120 are shown on the left side of the optical system 100. In the present invention, since the light source 110 and the spatial light modulator 120 can be combined in various forms, in FIG. 2 dealing with a general structure of an optical system, a diagram is replaced without showing an optical path. In FIGS. 3 and 4 dealing with a specific configuration of an optical system according to the type of spatial light modulator, the light source 110 and the spatial light modulator 120 will be shown in a separate form.
광원(110)은 광학계의 입사광의 원천이 되는 빛을 생성하는 부분이며, 단일 파장의 빛 혹은 일정 범위의 스펙트럼을 가진 빛이 생성되어 사용될 수 있다.The light source 110 is a part that generates light that is a source of incident light of the optical system, and may generate and use light of a single wavelength or light having a spectrum of a certain range.
공간 광 변조기(120)는 공간에서 빛을 변조하여 원하는 이미지(image)를 만들어 주는 장치이다. 전술한 도 1의 편광상태생성기나 편광상태분석기가 입사하는 빛을 받아들여 특정 편광 상태의 성분만을 걸러내거나, 위상을 정해진 만큼 지연시키는 등의 역할을 하는 반면, 공간 광 변조기는 주어진 빛의 빔-단면에 대하여 특정 부분은 빛을 통과시키고, 특정 부분은 빛을 통과시키지 않음으로써, 입력된 빛이 사용자가 원하는 모양을 가진 상태로 출력되도록 한다. The spatial light modulator 120 is a device that modulates light in space to create a desired image. While the polarization state generator or the polarization state analyzer of FIG. 1 receives incident light and filters out only components of a specific polarization state or delays the phase by a predetermined amount, the spatial light modulator is a beam of a given light. With respect to the cross section, a specific portion passes light and a specific portion does not pass light, so that the input light is output in a state having a shape desired by the user.
본 명세서에서는 빛을 통과시키거나 통과시키지 않는 최소 단위가 되는 부분을 화소(pixel)로 정의하고, 각 화소가 빛을 통과시키는 상태를 온(on), 빛을 통과시키지 않는 상태를 오프(off)라고 부르기로 한다. In this specification, a portion that becomes the smallest unit that allows or does not pass light is defined as a pixel, and the state in which each pixel passes light is on, and the state in which light does not pass is off. I will call it.
외부에서 보았을 때, 공간 광 변조기(120)는 화소들이 일정한 배열(array)로 배치된 면광원 또는 디스플레이처럼 보일 수 있다. 이 때 화소들은 임의의 배열을 가질 수 있는데, 예컨대 2차원 사각형 어레이(array)의 형태일 수 있다. 이 경우 각 화소는 카테시안 좌표계(Cartesian coordinate system)의 좌표에 대응될 수 있다. 또는 화소들은 2차원 원형 어레이의 형태일 수 있다. 이 경우 각 화소는 극점 좌표계의 좌표에 대응될 수 있다. 본 발명은 공간 광 변조기의 각 화소의 특정한 배열 방식이나 그 화소를 온/오프하는 방법, 즉 구체적인 구동 방식에 한정되지 않는다.When viewed from the outside, the spatial light modulator 120 may look like a surface light source or a display in which pixels are arranged in a certain array. In this case, the pixels may have an arbitrary arrangement, for example, in the form of a two-dimensional rectangular array. In this case, each pixel may correspond to a coordinate of a Cartesian coordinate system. Alternatively, the pixels may be in the form of a two-dimensional circular array. In this case, each pixel may correspond to the coordinates of the pole coordinate system. The present invention is not limited to a specific arrangement method of each pixel of a spatial light modulator or a method of turning on/off the pixel, that is, a specific driving method.
공간 광 변조기(120)는 그 구체적인 구현 방식에 한정되지 않고 입력된 빛에 대하여 사용자가 원하는 상(image)을 만들어 출력하는 기기를 일컫는 것으로 이해될 수 있다. 사용자는 공간 광 좌표기에 연결된 제어 모듈(도면에 도시되지 않음)을 사용하여 각 화소의 온/오프를 조절할 수 있으며, 그에 따라 미리 지정한 대로 원하는 이미지를 그려낼 수 있다. 공간 광 변조기(120)의 예시적인 유형은 뒤에서 자세히 다루어질 것이다.The spatial light modulator 120 is not limited to a specific implementation method, and may be understood as referring to a device that creates and outputs an image desired by a user for input light. The user can control the on/off of each pixel using a control module (not shown in the drawing) connected to the spatial light coordinate device, and accordingly, can draw a desired image as specified in advance. An exemplary type of spatial light modulator 120 will be discussed in detail later.
공간 광 변조기(120)에 의해 변조된 빛은 선택적 구성인 릴레이 렌즈(relay lens)(130a, 130b)를 지나치는데, 이것은 광 경로 상의 빔 직경(beam diameter)이 지나치게 넓어지는 것을 방지하고 빔을 일정한 범위 안으로 제한하려는 것이다.The light modulated by the spatial light modulator 120 passes through the optional relay lenses 130a, 130b, which prevents the beam diameter on the optical path from becoming too wide and keeps the beam constant. It is intended to be limited within range.
이후 편광상태생성기에 해당하는 소자들을 지나게 되는데, 도 2에서는 예시로서 편광자(130c), 보상기(130d)가 도시되어 있다. 다만, 이는 예시적인 소자들이며 당업자는 다른 소자들을 사용하여 다른 형태의 편광상태생성기를 구성할 수도 있다.After that, the elements corresponding to the polarization state generator are passed. In FIG. 2, a polarizer 130c and a compensator 130d are illustrated as examples. However, these are exemplary devices, and a person skilled in the art may construct other types of polarization state generators using other devices.
편광상태생성기를 통과한 빛은 원하는 값의 편광 상태를 가지게 되며, 이 상태에서 빔 스플리터(beam splitter)(140)에 의해 경로가 꺾이면서 도면 상의 하단으로 가게 된다. 하단에는 대물렌즈(150)가 있으며, 그 전에 후방 초점 면(back focal plane, 200)을 통과하게 되는데, 후방 초점 면에 대해서는 도 11, 도 12 및 그에 대한 설명에서 좀 더 자세히 다루어질 것이다.The light passing through the polarization state generator has a polarization state of a desired value, and in this state, the path is bent by the beam splitter 140 and goes to the bottom of the drawing. There is an objective lens 150 at the bottom, which passes through a back focal plane 200 before that, and the rear focal plane will be described in more detail in FIGS. 11 and 12 and the description thereof.
대물렌즈를 통과한 빛은 렌즈의 작용에 의해 경로가 휘게 되어, 시료(300)의 특점 지점에 입사된다. 이로서 입사 경로가 완성된다.The path of light passing through the objective lens is bent by the action of the lens, and is incident on the special point of the specimen 300. This completes the incident path.
이후, 입사 지점에서 시료에 의해 편광 상태에 변화가 생긴 반사광이 시료로부터 방출되어 대물렌즈(150)를 다시 통과한 뒤, 후방 초점 면(200)과 빔 스플리터(140)를 지나 도면 상의 상단으로 가게 되며, 편광상태분석기에 해당하는 소자들을 지나게 되는데, 도 2에서는 예시로서 편광자(160)가 도시되어 있다. Thereafter, the reflected light having a change in the polarization state by the sample at the point of incidence is emitted from the sample and passes through the objective lens 150 again, and then passes through the rear focal plane 200 and the beam splitter 140 and goes to the top of the drawing. And passes through elements corresponding to the polarization state analyzer. In FIG. 2, a polarizer 160 is shown as an example.
편광상태분석기를 통과한 반사광은 접안렌즈(170)를 지나 광감지기(180)에 도달한다. 광감지기에 도달된 빛은 전기 신호로 변환되며, 광학 소자, 예컨대 편광자(130c) 소자를 회전시켜 그에 따른 광감지기의 세기(intensity) 변화를 측정하여, 전술한 시료의 물성을 분석하게 된다.The reflected light passing through the polarization state analyzer passes through the eyepiece 170 and reaches the light detector 180. The light reaching the photodetector is converted into an electrical signal, and the optical device, for example, the polarizer 130c, is rotated to measure the change in intensity of the photodetector accordingly to analyze the physical properties of the above-described sample.
입사광과 반사광의 경로 및 전술한 소자의 구성은 예시적인 것이며, 당업자는 본 발명의 본질적인 구성을 유지하면서 광학 소자의 조합을 달리하여 목적에 맞는 광학계를 설계할 수 있으며, 이는 모두 본 발명의 범위에 포함되는 것이다.The paths of the incident light and the reflected light and the configuration of the above-described elements are exemplary, and those skilled in the art can design an optical system suitable for the purpose by varying the combination of optical elements while maintaining the essential configuration of the present invention. It is included.
(2) 공간 광 변조기의 종류에 따른 광학계의 구조 (도 3, 도 4)(2) Structure of optical system according to the type of spatial light modulator (Fig. 3, Fig. 4)
도 3은 본 발명의 일 실시예에 따른 광학계에서 공간 광 변조기(120)로 디지털 광 프로젝터(digital light projector, DLP) 또는 LCoS(Liquid Crystal on Silicon) 방식의 마이크로디스플레이(microdisplay)를 사용한 경우의 광학계의 구조를 도시한 개념도이다. 디지털 광 프로젝터의 구체적인 구조 및 작동방식은 도 5, 도 6 및 관련된 설명에서, LCoS 방식의 마이크로디스플레이의 구체적인 구조 및 작동방식은 도 7 및 관련된 설명에서 자세히 다루어질 것이다.3 is an optical system in the case of using a digital light projector (DLP) or a liquid crystal on silicon (LCoS) microdisplay as the spatial light modulator 120 in the optical system according to an embodiment of the present invention. It is a conceptual diagram showing the structure of. The detailed structure and operation method of the digital light projector will be described in detail in FIGS. 5 and 6 and the related description, and the specific structure and operation method of the LCoS type microdisplay will be described in detail in FIG. 7 and the related description.
도 3에서 광원(110)은 공간 광 변조기(120)와 광 경로 상 동축 혹은 일직선 상에 배열되지 않는다. 도면에서는 일 예시로서 광원(110)에서 나온 빛이 비스듬한 각도로 공간 광 변조기(120)에 입사된 뒤 반사되고 있음을 볼 수 있다.In FIG. 3, the light source 110 is not arranged coaxially or in a straight line with the spatial light modulator 120 in the optical path. In the drawing, as an example, it can be seen that light emitted from the light source 110 is incident on the spatial light modulator 120 at an oblique angle and then reflected.
위에서는 광원(110)이 공간 광 변조기(120)에 동축 혹은 일직선상에 배열되지 않은 경우로서 디지털 광 프로젝터와 LCoS 방식의 마이크로디스플레이만을 예로 들고 있으나, 다른 방식의 공간 광 변조기(120)도 유사한 방식 또는 다른 방식으로 사용될 수 있으며, 이러한 변용은 모두 본 발명의 범위에 포함되는 것이다.Above, only the digital light projector and the LCoS microdisplay are exemplified as the case where the light source 110 is not arranged coaxially or in a straight line with the spatial light modulator 120, but other spatial light modulators 120 are also similar. Alternatively, it may be used in other ways, and all such modifications are included in the scope of the present invention.
도 4는 본 발명의 일 실시예에 따른 광학계에서 공간 광 변조기(120)로 투과형 액정 디스플레이(transmissive liquid crystal display)를 사용한 경우의 광학계의 구조를 도시한 개념도이다. 투과형 액정 디스플레이의 구체적인 구조 및 작동방식은 도 8 및 관련된 설명에서 자세히 다루어질 것이다.4 is a conceptual diagram showing the structure of an optical system when a transmissive liquid crystal display is used as the spatial light modulator 120 in the optical system according to an embodiment of the present invention. The specific structure and operation of the transmissive liquid crystal display will be dealt with in detail in Fig. 8 and the related description.
도 4에서 광원(110)은 공간 광 변조기(120)와 광 경로상 동축 혹은 일직선으로, 공간 광 변조기(120)의 앞에 배치된다. 따라서 광원(110)에서 나온 빛은 공간 광 변조기(120)를 투과하여 지나게 된다.In FIG. 4, the light source 110 is disposed in front of the spatial light modulator 120 in a coaxial or straight line with the spatial light modulator 120 in an optical path. Accordingly, the light emitted from the light source 110 passes through the spatial light modulator 120.
위에서는 광원(110)이 공간 광 변조기(120)에 동축 혹은 일직선상에 배열되는 경우로서 투과형 액정 디스플레이만을 예로 들고 있으나, 다른 방식의 공간 광 변조기(120)도 유사한 방식 또는 다른 방식으로 사용될 수 있으며, 이러한 변용은 모두 본 발명의 범위에 포함되는 것이다.In the above, the light source 110 is arranged coaxially or in a straight line with the spatial light modulator 120, and only a transmissive liquid crystal display is given as an example, but the spatial light modulator 120 of another method may be used in a similar manner or in a different manner. , All such modifications are included in the scope of the present invention.
또한 도 2 내지 도 4에서는 광원(110) 및 공간 광 변조기(120)의 특정 조합만이 도시되고 있으나, 본 발명은 양 소자의 구체적인 결합 방식에 한정되지 않는다.In addition, only a specific combination of the light source 110 and the spatial light modulator 120 is shown in FIGS. 2 to 4, but the present invention is not limited to a specific combination method of both devices.
(3) 공간 광 변조기의 예시 (도 5 내지 도 8)(3) Examples of spatial light modulators (FIGS. 5 to 8)
본 발명은 임의의 공간 광 변조기(120)에 대해 구현될 수 있다. 이하에서는 본 발명에서 사용가능한 예시적인 공간 광 변조기(120)의 구조 및 작동방식에 대해 설명한다.The present invention can be implemented for any spatial light modulator 120. Hereinafter, a structure and operation method of an exemplary spatial light modulator 120 usable in the present invention will be described.
도 5 및 도 6은 본 발명의 일 실시예에 의한 광학계의 공간 광 변조기(120)의 예시인 디지털 광 프로젝터 및 디지털 광 프로젝터를 구성하는 소자인 디지털 마이크로미러 장치(digital micromirror device, DMD)를 도시한 개념도이다.5 and 6 illustrate a digital optical projector that is an example of a spatial light modulator 120 of an optical system according to an embodiment of the present invention, and a digital micromirror device (DMD) that is an element constituting the digital light projector. It is a conceptual diagram.
도 5에 도시된 디지털 광 프로젝터는 디지털 마이크로미러 장치가 어레이(array)를 이루어 배열된 것이며, 디지털 마이크로미러 장치는 미세전자기계시스템(micro electro-mechanical system, MEMS)으로 제작된 미소크기의 거울이다. 즉, 디지털 광 프로젝터에서 각 디지털 마이크로미러 장치는 화소(pixel)의 역할을 한다. 도 5의 디지털 광 프로젝터에서는 디지털 마이크로미러 장치가 1024열과 768행의 어레이를 이루고 있으나, 어레이를 구성하는 열과 행의 숫자는 예시적인 것이며, 임의의 다른 숫자의 열과 행을 가질 수 있다.The digital optical projector shown in FIG. 5 is a digital micromirror device arranged in an array, and the digital micromirror device is a micro-sized mirror made of a micro electro-mechanical system (MEMS). . That is, in a digital light projector, each digital micromirror device serves as a pixel. In the digital optical projector of FIG. 5, the digital micromirror device constitutes an array of 1024 columns and 768 rows, but the number of columns and rows constituting the array is exemplary, and may have any other number of columns and rows.
본 발명에 일 실시예에 의한 디지털 광 프로젝터는 임의의 장치를 통해 구현될 수 있는데, 예컨대 텍사스-인스트루먼츠(Texas Instruments)사의 디지털 광 프로젝터 등을 사용하여 구현될 수 있하다.The digital light projector according to an embodiment of the present invention may be implemented through an arbitrary device, for example, a digital light projector manufactured by Texas Instruments.
도 6에는 2개의 디지털 마이크로미러 장치(120)가 도시되어 있다. 디지털 마이크로미러 장치(120)의 하부에는 전극이 있어 외부로부터 전기 신호를 수신할 수 있고, 상부에는 반사경이 있어 빛을 반사시킨다. 하부의 전극에 전기 신호가 인가되면 상부의 반사경을 떠받치는 힌지(hinge)가 휘게 되면서, 반사경의 각도가 조절된다. In FIG. 6, two digital micromirror devices 120 are shown. There is an electrode under the digital micromirror device 120 to receive an electrical signal from the outside, and a reflector is provided at the top to reflect light. When an electric signal is applied to the lower electrode, the hinge supporting the upper reflector is bent, and the angle of the reflector is adjusted.
외부에서 들어온 빛(121)은 디지털 마이크로미터 장치의 반사경(120)의 각도에 따라, 투사 렌즈(122)로 반사되어 외부로 방출되거나, 흡광판(123)으로 반사되어 외부로 방출되지 않은 채 흡수된다. 도 6에서, 오른쪽에 도시된 디지털 마이크로미러 장치는 빛(121)을 투사 렌즈(122)로 반사하고 있는 반면, 왼쪽에 도시된 디지털 마이크로미러 장치는 빛(121)을 흡광판(123)으로 반사하고 있다. 디지털 광 프로젝터의 외부에서 볼 때, 오른쪽에 도시된 디지털 마이크로미러 장치에 대응하는 픽셀은 빛을 방출하는 on 상태인 것으로 보이고, 왼쪽에 도시된 디지털 마이크로미러 장치에 대응하는 픽셀은 빛을 방출하지 않는 off 상태인 것으로 보인다. 결과적으로, 각각의 디지털 마이크로미러 장치의 하부 전극과 연결된 전기 회로를 이용하여 전기 신호를 인가하거나 인가하지 않음으로써, 개별 디지털 마이크로미러 장치의 빛을 온/오프(on/off)할 수 있게 된다. Light 121 from the outside is reflected by the projection lens 122 and emitted to the outside according to the angle of the reflector 120 of the digital micrometer device, or is reflected by the light absorption plate 123 and is absorbed without being emitted to the outside. do. In FIG. 6, the digital micromirror device shown on the right reflects the light 121 to the projection lens 122, while the digital micromirror device shown on the left reflects the light 121 to the light absorbing plate 123. Are doing. When viewed from the outside of the digital light projector, the pixels corresponding to the digital micromirror device shown on the right appear to be in the on state to emit light, and the pixels corresponding to the digital micromirror device shown on the left do not emit light. It appears to be in the off state. As a result, by applying or not applying an electric signal using an electric circuit connected to the lower electrode of each digital micromirror device, it is possible to turn on/off the light of the individual digital micromirror device.
예컨대 신호가 온(on)이면, 힌지 각도를 조절하여 빛이 투사 렌즈(122)를 향하게 하고, 신호가 오프(off)이면, 힌지 각도를 조절하여 빛이 흡광판(123)으로 반사되도록 할 수 있다. 전기 신호와 빛의 켜지고 꺼짐은 반대로 대응되게 할 수도 있으며, 이러한 변용은 모두 본 발명의 범위에 속하는 것이다.For example, when the signal is on, the hinge angle is adjusted to direct light to the projection lens 122, and when the signal is off, the hinge angle can be adjusted so that the light is reflected to the light absorbing plate 123. have. Turning on and off of the electric signal and light may be made to correspond to the opposite, and all such variations are within the scope of the present invention.
다시 도 5로 돌아가면, 디지털 광 프로젝터의 각 화소는 예컨대 컴퓨터를 이용하여 외부로부터의 신호에 의해 온/오프 할 수 있으므로, 원하는 모양, 예컨대 원형, 사각형, 심지어 텍스트나 그림의 형태를 가진 광원을 생성 가능하며, 이 신호를 미리 정해진 데이터에 의하여 일정한 주사율(refresh rate)로 제어함으로써, 동영상에 대응하는 광원을 만들어 낼 수도 있다.Returning to Fig. 5, each pixel of the digital light projector can be turned on/off by a signal from the outside using, for example, a computer, so that a light source having a desired shape, such as a circle, a square, or even a text or picture, can be used. It can be generated, and by controlling this signal at a constant refresh rate based on predetermined data, a light source corresponding to a moving picture can be created.
도 2를 참조하면, 본 발명의 일 실시예에 의한 광학계에서는 광원으로부터 나온 빛을 편광상태생성기로 바로 주입하지 않고 공간 광 변조기(120), 위에서 설명된 실시예에서는 디지털 광 프로젝터에 먼저 입사시키기 때문에, 편광상태생성기(도 2에서는 그에 앞서 릴레이 렌즈(130a, 103b)를 통과함)에 입사되는 빛은 공간 광 변조기(120)에 의해 원하는 형태의 모양으로 편집된 형태가 된다.2, in the optical system according to an embodiment of the present invention, light from a light source is not directly injected into a polarization state generator, but a spatial light modulator 120 is first incident on the digital light projector. , Light incident on the polarization state generator (passing through the relay lenses 130a and 103b prior to that in FIG. 2) is edited into a desired shape by the spatial light modulator 120.
LCoS 방식의 마이크로디스플레이는 개별 소자가 어레이를 이루어 배열된 점에서는 도 5에 도시된 디지털 광 프로젝터와 유사하나, 그 개별 소자가 디지털 마이크로미러 장치가 아닌 LCoS 소자라는 점에서 차이가 있다. 즉, LCoS 방식의 마이크로디스플레이에서 LCoS 소자는 화소(pixel)의 역할을 한다.The LCoS type microdisplay is similar to the digital optical projector shown in FIG. 5 in that individual elements are arranged in an array, but the individual elements are not a digital micromirror device but an LCoS element. That is, in the LCoS microdisplay, the LCoS device serves as a pixel.
도 7은 본 발명의 일실시예에 의한 광학계의 공간 광 변조기의 예시인 LCoS 방식의 마이크로디스플레이의 단일 소자(이하, 'LCoS 소자'라 함)를 도시한 개념도이다. 7 is a conceptual diagram showing a single device (hereinafter referred to as an “LCoS device”) of an LCoS type microdisplay that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention.
도 7에 도시된 LCoS 소자는 그 구조면에서 공지된 액정 디스플레이(liquid crystal display, LCD)의 단일 소자와 대체로 유사하나, 유리 기판 대신 실리콘 기판 위에 형성되어 있다는 점 등에서 다소 차이가 있다. 실리콘 기판 위에는 CMOS 소자(127)가 배치되어 있으며, 그 위로 반사막, 액정(126), 배향막, 투명 전극(125), 액정을 외부로부터의 물리적 손상에서 보호하기 위한 유리판이 배치되어 있고, 유리판 위에는 광원으로부터 입사광의 각도를 고려하여 비스듬하게 배치된 편광판(124)이 배치된다.The LCoS device shown in FIG. 7 is substantially similar to a single device of a known liquid crystal display (LCD) in terms of its structure, but differs somewhat in that it is formed on a silicon substrate instead of a glass substrate. A CMOS element 127 is disposed on the silicon substrate, a reflective film, a liquid crystal 126, an alignment film, a transparent electrode 125, and a glass plate to protect the liquid crystal from physical damage from the outside are disposed on the silicon substrate. The polarizing plate 124 is disposed obliquely in consideration of the angle of incident light from.
도 7에서, 외부의 광원(121)으로부터 입사된 빛은 편광판(124)을 거쳐 액정(126)에 도달한다. 액정(126)의 하부에 배치된 CMOS 소자(127)와 액정(126)의 상부에 배치된 투명 전극(125) 사이에 전압을 인가하거나 인가하지 않으면, 그에 따라 액정(126)의 상태가 변화하며, 액정(126)의 상태에 따라 광원(121)으로부터 들어온 빛이 액정(126)에 입사된 후 반사되어 나갈 때 반사된 빛의 편광 상태가 변화하고, 그에 따라 액정(126)의 상부에 배치된 편광판(124)을 통과하거나 통과하지 않게 된다. 따라서 액정에 인가되는 전압을 조절함으로써 LCoS 소자가 빛을 반사하거나 반사하지 않게 만들 수 있으며, 이 방식으로 LCoS 방식의 마이크로디스플레이의 개별 화소의 온/오프가 구현될 수 있다. In FIG. 7, light incident from an external light source 121 passes through a polarizing plate 124 and reaches the liquid crystal 126. If a voltage is applied or not applied between the CMOS element 127 disposed below the liquid crystal 126 and the transparent electrode 125 disposed above the liquid crystal 126, the state of the liquid crystal 126 changes accordingly. , Depending on the state of the liquid crystal 126, when light from the light source 121 is incident on the liquid crystal 126 and then reflected, the polarization state of the reflected light changes, and accordingly, the polarization state of the reflected light changes. It passes through or does not pass through the polarizing plate 124. Accordingly, by adjusting the voltage applied to the liquid crystal, the LCoS element can reflect or not reflect light, and in this way, the individual pixels of the LCoS type microdisplay can be turned on/off.
도 8은 본 발명의 일 실시예에 의한 광학계의 공간 광 변조기의 예시인 투과형 액정 디스플레이의 단일 소자(이하, '투과형 LC 셀'이라 함)를 도시한 개념도이다. 도 8에 도시된 투과형 LC 셀은 업계에 공지된 액정 디스플레이의 셀과 유사한 구조이며, 설명을 위해 일부 구조, 예컨대 투명 전극이 생략되어 단순화된 형태로 제시되었다. 도 7의 LCoS 소자와 비교하면 양쪽 면이 유리로 되어 있다는 점을 인식할 수 있다.8 is a conceptual diagram showing a single element (hereinafter referred to as a'transmissive LC cell') of a transmissive liquid crystal display that is an example of a spatial light modulator of an optical system according to an embodiment of the present invention. The transmissive LC cell shown in FIG. 8 has a structure similar to a cell of a liquid crystal display known in the art, and is presented in a simplified form by omitting some structures such as transparent electrodes for description. Compared with the LCoS device of FIG. 7, it can be recognized that both sides are made of glass.
도 8의 (a)에 도시된 투과형 LC 셀을 보면, 양쪽 유리판(128)(좀 더 일반적으로는 유리 이외의 빛을 투과할 수 있는 재질이 될 수 있음) 사이에 액정(129)이 배치되어 있으며, 액정 사이에 전압원 V(t)이 연결되어 있다. 도 8의 (a)에서 투과형 LC 셀에 전압이 인가되지 않은 경우, 액정(129)은 무질서한 방향을 가지고 배열되는 반면, 도 8의 (b)에서 전압이 인가되면, 액정(129)이 같은 방향으로 정렬되고, 그에 따라 빛이 통과할 수 있게 된다. 즉 액정(129)은 전압의 인가여부에 따라 정렬되거나 정렬되지 않으며, 정렬 상태에 따라 빛을 투과시키거나 투과시키지 않을 수 있다. 따라서 각 투과형 LC 셀에 전압을 인가하거나 인가하지 않음으로써, 각 투과형 LC 셀을 온/오프할 수 있다.Looking at the transmissive LC cell shown in Fig. 8A, a liquid crystal 129 is disposed between both glass plates 128 (more generally, a material capable of transmitting light other than glass) And a voltage source V(t) is connected between the liquid crystals. In Fig. 8(a), when no voltage is applied to the transmissive LC cell, the liquid crystal 129 is arranged in a disordered direction, whereas when a voltage is applied in Fig. 8(b), the liquid crystal 129 is in the same direction. Are aligned, and light can pass through accordingly. That is, the liquid crystal 129 may or may not be aligned depending on whether a voltage is applied, and may or may not transmit light depending on the alignment state. Therefore, each transmissive LC cell can be turned on/off by applying or not applying a voltage to each transmissive LC cell.
다만 액정 디스플레이는 여러가지 방식이 있으며, 도 8 및 관련된 위 설명에서는 전압이 인가되어 액정이 정렬된 경우에 빛이 통과하는 것으로 설명되었으나, 반대로 전압을 인가하여 액정이 정렬된 경우에 빛이 통과하지 않도록 설계하는 것도 가능하다.However, there are various types of liquid crystal displays, and in Fig. 8 and related description above, it has been described that light passes when a voltage is applied and the liquid crystals are aligned. However, when the liquid crystals are aligned by applying a voltage, the light does not pass through. It is also possible to design.
(4) 공간 광 변조기(120)의 구조에 따른 편광상태생성기의 기능 수행 (도 9)(4) Performing the function of the polarization state generator according to the structure of the spatial light modulator 120 (Fig. 9)
본 발명의 일 실시예에 의한 광학계의 구성에서, 공간 광 변조기(120)는 편광상태생성기와 분리된 별개의 소자인 것으로 묘사되었다. 예컨대 도 2 내지 도 4에서 편광상태생성기(120)는 편광상태생성기에 대응하는 소자인 (130a) 내지 (130d) 등과 분리된 별개의 소자인 것으로 묘사되었다. 그러나 공간 광 변조기(120)는 그 구조에 따라 공간 광 변조기(120) 스스로가 편광상태를 변화시키는 기능을 일부 또는 전부 수행할 수 있다.In the configuration of the optical system according to an embodiment of the present invention, the spatial light modulator 120 has been described as being a separate element separated from the polarization state generator. For example, in FIGS. 2 to 4, the polarization state generator 120 is depicted as a separate device separated from the devices 130a to 130d corresponding to the polarization state generator. However, the spatial light modulator 120 may perform part or all of the function of changing the polarization state by itself according to its structure.
당업자라면 편광상태생성기(120)의 단일 소자에 이러한 편광상태생성기의 역할을 수행하는 소자를 결합시키거나, 편광상태생성기(120)의 전체 기기에 일체로 편광상태생성기의 역할을 수행하는 소자를 결합하는 것을 구상할 수 있으며, 이러한 구성은 모두 본 발명의 범위에 포함되는 것이다.Those skilled in the art may combine an element that plays the role of such a polarization state generator with a single element of the polarization state generator 120, or combines an element that plays the role of a polarization state generator integrally with the entire device of the polarization state generator 120. It can be envisioned, and all of these configurations are included in the scope of the present invention.
여기에서는 예시로서 투과형 액정 디스플레이의 투과형 LC 셀의 구조에서 편광상태생성기의 역할을 일부 수행하는 구조를 설명할 것이나, 본 발명은 이하에서 도시되는 방식에 한정되는 것이 아니다.Here, as an example, a structure that partially serves as a polarization state generator in the structure of a transmission type LC cell of a transmission type liquid crystal display will be described, but the present invention is not limited to the method shown below.
도 9는 본 발명의 일 실시예에 의한 광학계의 공간 광 변조기의 예시인 투과형 액정 디스플레이의 단일 소자인 투과형 LC 셀에 인가되는 전압에 따라 액정이 투과시키는 색상 및 편광 상태가 달라지는 것을 도시한 개념도이다. FIG. 9 is a conceptual diagram showing that the color and polarization state of the liquid crystal transmits differently according to the voltage applied to the transmissive LC cell, which is a single element of a transmissive liquid crystal display, which is an example of a spatial light modulator of an optical system according to an embodiment of the present invention. .
도 8의 투과형 LC 셀과 비교하여, 도 9의 (a) 내지 (e)의 구조에서는 좌측과 우측에 편광판(회색)이 부가되어 있다(화살표는 편광 방향을 나타냄). 좌측에서 입사된 빛은 좌측 편광판을 지나면서 편광된 성분의 빛만이 통과하며, 액정을 통과하여 편광 상태에 변화가 일어나고, 우측 편광판에 의해 정해진 편광 방향 성분의 빛만이 우측 편광판을 통과하여 기기를 벗어나게 된다.Compared with the transmissive LC cell of Fig. 8, in the structures of Figs. 9A to 9E, polarizing plates (gray) are added to the left and right (arrows indicate polarization directions). The light incident from the left passes through the left polarizing plate, only the polarized light passes through, and the polarization state changes through the liquid crystal, and only the light of the polarization direction component determined by the right polarizing plate passes through the right polarizing plate and leaves the device. do.
도 9의 (a)는 액정에 전압이 인가되지 않은 상태, 즉 V(t) = 0인 상태이다. 전압이 인가되지 않았기 때문에, 액정은 정렬되지 않은 상태이다. 좌측에서 입사된 빛은 좌측 편광판을 지나면서 편광된 성분의 빛만이 통과한다. 이 빛은 액정에 입사되는데, 액정이 정렬되지 않아 편광 방향의 변화없이 액정을 통과하게 된다. 액정을 통과한 빛은 우측 편광판에 도달하는데, 우측 편광판은 좌측 편광판과는 수직인 편광 방향을 가지고 있다. 예컨대, 좌측 편광판의 편광 방향이 45도인 경우 우측 편광판의 편광 방향은 135도가 된다. 우측 편광판에 도달한 빛은 우측 편광판과 수직인 편광 방향을 가지고 있으므로, 우측 편광판을 통과하지 못한다. 결과적으로 이 화소는 외부에서 볼 때 빛을 방출하지 않아 검은색으로 보이며, 화소가 오프(off) 상태가 된다.9A shows a state in which a voltage is not applied to the liquid crystal, that is, V(t) = 0. Since no voltage is applied, the liquid crystal is in an unaligned state. Light incident from the left passes through the left polarizing plate and only the light of the polarized component passes. This light is incident on the liquid crystal, but because the liquid crystal is not aligned, it passes through the liquid crystal without changing the polarization direction. The light passing through the liquid crystal reaches the right polarizing plate, and the right polarizing plate has a polarization direction perpendicular to the left polarizing plate. For example, when the polarization direction of the left polarizing plate is 45 degrees, the polarization direction of the right polarizing plate is 135 degrees. Since the light reaching the right polarizing plate has a polarization direction perpendicular to the right polarizing plate, it cannot pass through the right polarizing plate. As a result, when viewed from the outside, this pixel does not emit light, so it appears black, and the pixel is turned off.
도 9의 (b) 내지 (e)는 액정에 전압이 인가되고 인가되는 전압이 증가함에 따라 액정이 정렬되는 상태를 도시하고 있다. 인가되는 전압의 세기는 연속값을 가질 수 있으며, 액정은 완전히 정렬되지 않거나 완전히 정렬된 상태 뿐만이 아닌 연속적인 중간 상태들을 가질 수 있다. 액정이 점점 더 정렬됨에 따라, 좌측 편광판을 통과하여 액정에 입사하는 빛이 액정에 의해 편광 상태가 변화되는 정도가 점점 더 커진다. 액정이 완전히 정렬된 도 9의 (e)에서는 좌측으로부터 입사된 빛이 액정을 통과하면서 편광 방향이 90도 회전하게 되며, 그 결과 우측 편광판의 편광 방향과 일치하게 되어, 액정을 통과한 빛 전부가 우측 편광판을 통과할 수 있게 된다. 따라서 도 9의 (b) 내지 (e)에서 인가되는 전압이 증가할수록 우측 편광판을 통과하는 빛의 양이 증가하고, 이 화소는 외부에서 볼 때 검은색에서 어두운 회색, 어두운 회색에서 회색, 회색에서 밝은 회색, 밝은 회색에서 흰색으로 변화하게 되며, 도 9의 (e)의 흰색 화소는 온(on) 상태인 화소가 된다.9B to 9E illustrate a state in which a voltage is applied to the liquid crystal and the liquid crystal is aligned as the applied voltage increases. The strength of the applied voltage may have a continuous value, and the liquid crystal may have not only completely aligned or completely aligned states, but also continuous intermediate states. As the liquid crystal is more and more aligned, the degree to which the polarization state of the light passing through the left polarizing plate and incident on the liquid crystal is changed by the liquid crystal increases. In Fig. 9(e), in which the liquid crystals are completely aligned, the polarization direction rotates 90 degrees while the light incident from the left passes through the liquid crystal. As a result, the polarization direction coincides with the polarization direction of the right polarizing plate. It can pass through the right polarizer. Therefore, as the voltage applied in FIGS. 9B to 9E increases, the amount of light passing through the right polarizing plate increases, and this pixel is viewed from black to dark gray, dark gray to gray, and gray. It changes from light gray and light gray to white, and the white pixel in (e) of FIG. 9 becomes a pixel in an on state.
도 9의 (a) 내지 (e)에서, 우측 편광판의 존재로 인해 공간 광 변조기(120)에서 출력되는 빛은 선형 편광된 빛이 된다. 이것은 마치 공간 광 변조기(120)에 우측 편광판이 부재하고, 공간 광 변조기(120)와 분리된 편광상태생성기의 시작 부분에 편광판이 존재하는 것과 같은 효과를 가지게 된다. 즉, 공간 광 변조기(120)에 내장된 우측 편광판으로 인하여 공간 광 변조기(120)는 편광상태생성기의 일부 역할을 수행하게 된다.9A to 9E, light output from the spatial light modulator 120 becomes linearly polarized light due to the presence of the right polarizing plate. This has the same effect as if there is no right polarizing plate in the spatial light modulator 120 and a polarizing plate exists at the beginning of the polarization state generator separated from the spatial light modulator 120. That is, due to the right polarizing plate built in the spatial light modulator 120, the spatial light modulator 120 plays a part of the polarization state generator.
또한 도 9의 (a) 내지 (e)에서 액정에 인가되는 전압의 세기에 따라 액정의 정렬 정도가 변화하고 그에 따라 액정을 통과하는 빛의 편광 상태를 변화시키는 정도가 달라지므로, 액정은 위상 변조의 역할을 하게 된다. 이것은 마치 공간 광 변조기(120)에 액정 대신 다른 방식으로 공간 광 변조를 수행하는 소자가 내장되어 있고, 공간 광 변조기(120)와 분리된 편광상태생성기의 시작 부분에 위상변조기가 존재하는 것과 같은 효과를 가지게 된다. 즉, 공간 광 변조기(120)의 액정으로 인하여 공간 광 변조기(120)는 편광상태생성기의 일부 역할을 수행하게 된다.In addition, since the degree of alignment of the liquid crystal changes according to the intensity of the voltage applied to the liquid crystal in (a) to (e) of FIG. 9 and the degree to which the polarization state of light passing through the liquid crystal changes accordingly, the liquid crystal is phase modulated. Will play the role of. This is as if the spatial light modulator 120 has an element that performs spatial light modulation in a different way instead of a liquid crystal, and a phase modulator exists at the beginning of the polarization state generator separated from the spatial light modulator 120. Will have. That is, due to the liquid crystal of the spatial light modulator 120, the spatial light modulator 120 plays a part of the polarization state generator.
따라서 본 발명의 일 실시예에 의한 광학계에서 공간 광 변조기(120)와 편광상태생성기가 별도의 구성요소로 기술된 경우라 하더라도, 공간 광 변조기(120)는 편광상태생성기의 일부 또는 전부 기능을 수행할 수 있는 것으로 이해되어야 한다.Therefore, even if the spatial light modulator 120 and the polarization state generator are described as separate components in the optical system according to an embodiment of the present invention, the spatial light modulator 120 performs some or all of the functions of the polarization state generator. It should be understood as what can be done.
3. 본 발명의 실시예들에 따른 광학계의 작동 원리3. Operating principle of the optical system according to the embodiments of the present invention
(1) 후방 초점 면에서 빛의 거동 (도 10, 도 11)(1) Light behavior in the rear focal plane (Figs. 10 and 11)
도 10과 도 11은 본 발명의 일 실시예에 의한 광학계에서 후방 초점 면(200)의 특성을 설명하기 위한 개념도이다.10 and 11 are conceptual diagrams for explaining characteristics of a rear focal plane 200 in an optical system according to an embodiment of the present invention.
도 10은 후방 초점 면(200) 상의 같은 점으로 입사한 빛은 시료(300)에 동일한 각도로 입사하게 됨을 설명하기 위한 것이다. 도 10에는 도 2의 후방 초점 면(200), 대물렌즈(150)(설명의 편의를 위해 선으로 단순화되어 표시됨), 시료(300)가 도시되어 있다. 광 경로 상의 A 지점과 B 지점에서 각각 3가지 빛의 경로가 도시되어 있는데, A와 B에서 나온 실선은 후방 초점 면(200)의 좌측 지점을, 파선은 후방 초점 면(200)의 가운데 지점을, 이점쇄선은 후방 초점 면(200)의 우측 지점을 통과하고 있다. 비록 광선의 출발점이 A와 B로 다르지만, 후방 초점 면(200)의 동일한 지점을 통과한 각 광선들은 대물렌즈(150)를 거쳐 시료(300)에 입사할 때 동일한 각도로 입사하게 된다. 즉, A 지점과 B 지점에서 후방 초점 면(200)의 좌측을 통과한 광선(실선)은 대물렌즈(150)를 거쳐 시료(300)에 입사할 때 좌측에서 θ의 각도로 입사하고, 후방 초점 면(200)의 가운데를 통과한 광선(파선)은 대물렌즈(150)를 거쳐 시료(300)에 수직으로 입사하고 있으며, 후방 초점 면(200)의 우측을 통과한 광선(이점쇄선)은 대물렌즈(150)를 거쳐 시료(300)에 입사할 때 우측에서 θ의 각도로 입사하는 것을 볼 수 있다. 10 is for explaining that light incident on the rear focal plane 200 at the same point is incident on the sample 300 at the same angle. In FIG. 10, the rear focal plane 200 of FIG. 2, the objective lens 150 (indicated by being simplified with lines for convenience of explanation), and the sample 300 are shown. Three light paths are shown at points A and B on the optical path, respectively. The solid lines from A and B indicate the left point of the rear focal plane 200, and the broken line indicates the center point of the rear focal plane 200. , The double-dashed line is passing through the right point of the rear focal plane 200. Although the starting points of the light rays are different from A and B, each light rays passing through the same point of the rear focal plane 200 are incident at the same angle when entering the specimen 300 through the objective lens 150. That is, the light rays (solid line) passing through the left side of the rear focal plane 200 at points A and B are incident at an angle of θ from the left when entering the sample 300 through the objective lens 150, and the rear focus The light ray (dashed line) passing through the center of the plane 200 is vertically incident on the sample 300 through the objective lens 150, and the light ray (double-dotted line) passing through the right side of the rear focal plane 200 is the objective. When entering the sample 300 through the lens 150, it can be seen that the incident is incident at an angle of θ from the right.
또한 후방 초점 면(200)의 좌측을 통과하는 광선(실선)과 후방 초점 면(200)의 우측을 통과하는 광선(이점쇄선)은 후방 초점 면(200)에서 대물 렌즈(150)의 중심축으로부터 등거리만큼 떨어진 지점을 통과하는데, 그 결과 시료(300)에 입사하는 각도가 동일함을 알 수 있다.In addition, the light rays passing through the left side of the rear focal plane 200 (solid line) and the light rays passing through the right side of the rear focal plane 200 (dashed-dotted line) are from the central axis of the objective lens 150 at the rear focal plane 200. It passes through a point separated by an equidistant distance, and as a result, it can be seen that the incident angle to the sample 300 is the same.
즉, 후방 초점 면(200)의 동일한 지점을 통과한 광선은 시료(300)에 동일한 각도로 입사하며, 이 각도는 대물렌즈(150)의 중심축으로부터의 거리에 따라 정해진다는 것이다.That is, the light rays passing through the same point of the rear focal plane 200 are incident on the specimen 300 at the same angle, and this angle is determined according to the distance from the central axis of the objective lens 150.
한편 도 11는 시료(300) 상의 다른 점으로부터 나온 빛이라도 같은 각도로 출발한 빛은 후방 초점 면(200) 상의 한 점에서 만나게 됨을 설명하기 위한 것이다. 이러한 원리는 도 10에서 광선의 경로를 역으로 추적해 보면 알 수 있다.Meanwhile, FIG. 11 is for explaining that even light from another point on the specimen 300 meets at a point on the rear focal plane 200. This principle can be seen by reversing the path of the light beam in FIG. 10.
도 11에는 시료(300), 대물렌즈(150)(설명의 편의를 위해 선으로 단순화되어 표시됨), 후방 초점 면(200)이 도시되어 있다. 시료(300) 상의 다른 점 A와 B에서 출발한 빛은 동일한 각도로 좌측으로 올라가거나(실선), 수직으로 올라가거나(파선), 우측으로 올라가는데(이점쇄선), 시료(300)에서의 출발점이 다름에도 불구하고 각도가 동일하였기 때문에 후방 초점 면(200) 상의 동일한 지점, 즉 각각 a, b, c에서 만나게 된다.In FIG. 11, a sample 300, an objective lens 150 (simplified and indicated by lines for convenience of explanation), and a rear focal plane 200 are shown. The light from different points A and B on the sample 300 rises to the left at the same angle (solid line), rises vertically (dashed line), or rises to the right (double-dotted line), and the starting point from sample 300 Despite this difference, since the angles were the same, they meet at the same points on the rear focal plane 200, that is, a, b, and c, respectively.
(2) 본 발명의 일 실시예에 의한 입사광의 후방 초점 면에서의 위치에 따른 조절가능성 (도 12, 도 13)(2) Controllability according to the position of the incident light in the rear focal plane according to an embodiment of the present invention (Figs. 12 and 13)
도 12와 도 13은 본 발명의 일 실시예에 의한 광학계의 광학계에서 입사광과 반사광의 관계를 설명하기 위한 개념도이다.12 and 13 are conceptual diagrams for explaining a relationship between incident light and reflected light in an optical system of an optical system according to an embodiment of the present invention.
먼저 도 12에서는 후방 초점 면(200), 대물렌즈(150), 시료(300)가 도시되어 있다. 시료(300)는 대물 렌즈(150)의 초점거리(f) 만큼 떨어진 지점에 위치되어 있다. 후방 초점 면(200)을 통과한 광선(실선, 파선)(편의상 후방 초점 면(200)을 수직으로 통과하는 광선만 도시됨)은 대물렌즈(150)를 지나 시료(300)에 입사되는데, 다음과 같은 점을 알 수 있다.First, in FIG. 12, the rear focal plane 200, the objective lens 150, and the sample 300 are shown. The sample 300 is located at a point separated by the focal length f of the objective lens 150. A light ray (solid line, broken line) passing through the rear focal plane 200 (for convenience, only a light ray passing vertically through the rear focal plane 200 is shown) passes through the objective lens 150 and enters the sample 300. You can see the same point.
첫째, 한 광선이 입사 후 반사될 때, 입사되는 각도와 반사되는 각도는 동일하다. (광학의 원리상 자명함)First, when one ray is incident and reflected, the incident angle and the reflected angle are the same. (Self-evident in the principle of optics)
둘째, 후방 초점 면(200)의 동일한 점을 통과한 광선은 시료(300)에 동일한 각도로 입사되며, 대물렌즈(150)의 중심축으로부터의 반경거리가 동일한 경우, 즉 도 6에서 좌우측의 파선, 또는 좌우측의 실선의 경우와 같은 때에는, 입사각의 값이 동일하다.Second, the light rays passing through the same point of the rear focal plane 200 are incident on the sample 300 at the same angle, and when the radial distance from the central axis of the objective lens 150 is the same, that is, the broken lines on the left and right sides in FIG. , Or in the case of the left and right solid lines, the value of the incident angle is the same.
다음으로 도 13은 대물렌즈(150)의 중심축을 중심으로 하는 극좌표계에서 후방 초점 면(200) 상의 각 지점에 입사한 입사광과 그에 따른 반사광의 상관관계를 표현한 개념도이다.Next, FIG. 13 is a conceptual diagram illustrating a correlation between incident light incident on each point on the rear focal plane 200 in a polar coordinate system centered on the central axis of the objective lens 150 and reflected light accordingly.
본 발명의 일 실시예에 의한 광학계에 의한 입사광은 대물렌즈(150) 및 시료(300)의 입사 전에는 모두 동일한 편광, 예컨대 이 예시에서는 x축 방향의 편광을 가지고 있다(실선).Incident light by the optical system according to an embodiment of the present invention all have the same polarization before incidence of the objective lens 150 and the sample 300, for example, polarization in the x-axis direction in this example (solid line).
그러나 각 입사광은 대물렌즈(150)의 중심축을 중심으로 하는 극좌표계에서의 각도(
Figure PCTKR2020006441-appb-I000010
)에 따라 휘는 방향이 다르므로, 그에 따라 입사면의 방향이 달라지고(각각 ①과 ①', ②와 ②', ③과 ③', ④와 ④' 사이의 파선) p 편광과 s 편광의 성분이 달라지며, 그 결과 반사광의 편광 성분도 달라지게 된다.
However, each incident light is an angle in the polar coordinate system centered on the central axis of the objective lens 150 (
Figure PCTKR2020006441-appb-I000010
), the direction of the incident surface is different (dashed lines between ① and ①', ② and ②', ③ and ③', and ④ and ④', respectively), and the components of p polarization and s polarization As a result, the polarization component of the reflected light is also different.
예컨대, 입사광 ①는 대물렌즈(150)를 통과하면서 -x축 방향으로 꺾인 경로로 시료(300)에 입사하게 되고, 그 결과 입사면(①과 ①' 사이의 파선)이 편광방향과 평행하게 되므로, 반사광의 편광이 입사광의 편광방향과 같은 편광 방향을 가진채 나오게 된다(①'). 또한 입사광 ③은 대물렌즈(150)를 통과하면서 -y축 방향으로 꺾인 경로로 시료(300)에 입사하게 되고, 그 결과 입사면(③과 ③' 사이의 파선)이 편광방향과 완전한 수직이 되며, s 편광만 있는 셈이 되어 반사광은 (위상 변화를 불문) p 편광 성분이 섞이지 않은 채로 나오게 된다(③').For example, the incident light ① passes through the objective lens 150 and enters the specimen 300 in a path curved in the -x-axis direction, and as a result, the incident surface (broken line between ① and ①') becomes parallel to the polarization direction. , The polarization of the reflected light comes out with the same polarization direction as the polarization direction of the incident light (①'). In addition, the incident light ③ passes through the objective lens 150 and enters the specimen 300 in a path curved in the -y axis direction, and as a result, the incident surface (broken line between ③ and ③') becomes completely perpendicular to the polarization direction. , it means that there is only s polarization, and the reflected light comes out without mixing the p polarization component (regardless of the phase change) (③').
반면 입사광 ②와 ④의 경우 대물렌즈(150)를 지나 꺾이게 되는 방향(중심축을 향한 방향)이 편광 방향과 완전한 평행도 완전한 수직도 아니므로, p 편광과 s 편광 성분을 모두 갖게 되며, 그 결과 각각의 반사광(②'와 ④')은 타원 편광이 된다.On the other hand, in the case of incident light ② and ④, since the direction to be bent past the objective lens 150 (direction toward the center axis) is neither completely parallel nor perfectly perpendicular to the polarization direction, it has both p polarization and s polarization components. The reflected light (②' and ④') becomes elliptically polarized light.
즉, 도 13에 의하면, 동일한 편광을 가진 입사광이라도, 후방 초점 면(200) 상의 위치, 정확히는 각도(
Figure PCTKR2020006441-appb-I000011
)에 따라 반사광의 p 편광과 s 편광의 성분이 변화하게 된다.
That is, according to FIG. 13, even if incident light having the same polarization, the position on the rear focal plane 200, precisely the angle (
Figure PCTKR2020006441-appb-I000011
), the p-polarized and s-polarized components of the reflected light change.
정리하면, 후방 초점 면(200)에서의 위치가, 대물렌즈(150)의 중심축을 원점으로 하는 극좌표계 상의 반지름(r)과 각도(
Figure PCTKR2020006441-appb-I000012
)에 대하여, 각도(
Figure PCTKR2020006441-appb-I000013
)을 조절함으로써 시료(300)에 입사하는 p 편광과 s 편광의 성분을 조절할 수 있게 되고, 반지름(r)을 조절함에 따라, 시료(300)에 입사하는 입사각(θ)을 조절할 수 있게 된다.
In summary, the position on the rear focal plane 200 is the radius (r) and the angle (r) on the polar coordinate system with the central axis of the objective lens 150 as the origin.
Figure PCTKR2020006441-appb-I000012
For ), angle (
Figure PCTKR2020006441-appb-I000013
), it is possible to adjust the components of the p-polarized light and the s-polarized light incident on the sample 300, and by adjusting the radius r, the angle of incidence (θ) incident on the sample 300 can be adjusted.
(3) 본 발명의 일 실시예에 따른 공간 광 변조기의 화소의 온/오프 조작을 통한 후방 초점 면에서의 위치 조절 (도 14 내지 도 17)(3) Position adjustment at the rear focal plane through on/off operation of pixels of the spatial light modulator according to an embodiment of the present invention (FIGS. 14 to 17)
이제 앞에서 설명한 공간 광 변조기(120)의 화소의 온/오프 조작을 이용하여 입사광의 후방 초점 면에서의 위치를 변화시키고, 그에 따라 물성을 측정하는 방법을 개시한다.Now, a method of changing the position of the incident light on the rear focal plane by using the on/off operation of the pixels of the spatial light modulator 120 described above and measuring physical properties accordingly is disclosed.
도 14 내지 도 17은 본 발명의 일 실시예에 따른 광학계에서, 공간 광 변조기(120)에 의해 후방 초점 면(200) 상에서 조광되는 위치를 조절하여 물성 측정을 수행하는 방법을 설명하기 위한 개념도이다.14 to 17 are conceptual diagrams for explaining a method of measuring physical properties by adjusting a position to be illuminated on the rear focal plane 200 by the spatial light modulator 120 in an optical system according to an embodiment of the present invention. .
도 14의 좌표평면은 후방 초점 면(200)상의 위치를 나타낸다. 앞서 설명한 바와 같이, 공간 광 변조기(120)를 사용하여 이 후방 초점 면(200) 상에서 어느 특정 지점에만 입사광이 들어가도록 하는 것이 가능하다. 특정 지점의 크기는 공간 광 변조기(120)의 화소 수와 화소당 면적에 따라 달라질 수 있으며, 더 많은 숫자의 화소가 집적된, 즉 더 고해상도(high resolution)의 공간 광 변조기(120)는 더 좁은 또는 더 정확한 지점에만 입사광을 지나가도록 할 수 있다.The coordinate plane of FIG. 14 represents a position on the rear focal plane 200. As described above, it is possible to enter the incident light only at a specific point on the rear focal plane 200 by using the spatial light modulator 120. The size of a specific point may vary depending on the number of pixels and the area per pixel of the spatial light modulator 120, and the spatial light modulator 120 in which a larger number of pixels are integrated, that is, a higher resolution, is narrower. Alternatively, the incident light can pass only at more precise points.
우선 후방 초점 면(200)의 극좌표계 상에서 반경을 r1으로 고정하고, 같은 반지름에 대하여 각도(
Figure PCTKR2020006441-appb-I000014
)를 0도 내지 360도로 달리해 가면서 입사광을 조사하고, 그에 따른 반사광을 측정한다(경로 ①). 이 경우 반경이 고정되었기 때문에 그에 따라 시료(300)에 조사되는 입사광의 입사각이 고정되며, 각도가 변화하면서 편광 성분이 변화되는 값이 시료(300)에 입사된다. 각도를 조절하는 방식은 0도에서 360도까지 연속적으로 측정하거나, 예컨대 0도, 45도, 90도와 같은 특정 각도에 대해 이산적으로 측정할 수 있으며, 측정 방향도 각도가 커지는 방향(반시계 방향)(도 14) 또는 감소하는 방향(시계 방향)(도 15)으로 측정할 수 있다.
First, the radius is fixed to r 1 on the polar coordinate system of the rear focal plane 200, and the angle (
Figure PCTKR2020006441-appb-I000014
The incident light is irradiated while varying) from 0 to 360 degrees, and the reflected light accordingly is measured (path ①). In this case, since the radius is fixed, the incident angle of the incident light irradiated to the sample 300 is fixed accordingly, and a value at which the polarization component changes as the angle changes is incident on the sample 300. The method of adjusting the angle can be measured continuously from 0 to 360 degrees, or discretely measured for specific angles such as 0, 45, and 90 degrees, and the measurement direction is also the direction in which the angle increases (counterclockwise ) (Fig. 14) or in a decreasing direction (clockwise) (Fig. 15).
정해진 반경에 대하여 각도 변화에 따른 측정을 완료하면, 반경을 다소 변화시킨 뒤(r1에서 r2로)(이하에서 이 반경의 차이를 변화값이라 한다), 다시 각도(
Figure PCTKR2020006441-appb-I000015
)를 0도에서 360도로 달리해 가면서 입사광을 조사하고, 그에 따른 반사광을 측정한다(경로 ②).
After completing the measurement according to the angle change for the specified radius, change the radius slightly (from r 1 to r 2 ) (hereinafter, the difference between this radius is called the change value), and then again the angle (
Figure PCTKR2020006441-appb-I000015
The incident light is irradiated while changing) from 0° to 360°, and the reflected light is measured (path ②).
앞서 말한 것과 같이 변화값과 측정하는 각도의 간격은 공간 광 변조기(120)의 해상도에 따라 달라질 수 있다. 변화값은 반경이 증가하는 값일 수도 있고, 감소하는 값일 수도 있으며, 반경에 따라 변화값 자체가 달라질 수도 있다. 즉, 반경이 1 -> 2 -> 3 -> 4와 같이 점증할 수도 있고, 4 -> 3 -> 2 -> 1로 감소할 수도 있으며, 10 -> 15 -> 18 -> 20과 같이 변화하되 증가폭이 감소하거나, 그 반대일 수도 있다.As described above, the interval between the change value and the measured angle may vary depending on the resolution of the spatial light modulator 120. The change value may be a value in which the radius increases or decreases, and the change value itself may vary according to the radius. In other words, the radius can increase gradually, such as 1 -> 2 -> 3 -> 4, or it can decrease to 4 -> 3 -> 2 -> 1, and change like 10 -> 15 -> 18 -> 20 However, the increase may decrease or vice versa.
위와 같은 반사광의 측정은 예시적으로 다음과 같은 시퀀스를 통해 구현될 수 있다: 상기 대물렌즈의 후방 초점 면(back focal plane)에서 렌즈 중심축을 원점으로 하는 극좌표계에 대하여, 반경(radius) 값을 1차 변수, 각도(radian) 값을 2차 변수로 두고, 2차 변수를 0도 내지 360도에서 변화시키고, 각 2차 변수의 변화 사이클마다 1차 변수를 미리 정해진 값에서 상기 공간 광 변조기의 해상도에 따라 정해지는 변화값(incremental value) 만큼 변화시키는 시퀀스.The measurement of the reflected light as described above may be exemplarily implemented through the following sequence: For a polar coordinate system whose origin is the lens center axis in the back focal plane of the objective lens, a radius value is set. The primary variable and the angular (radian) value are set as secondary variables, the secondary variable is changed from 0 to 360 degrees, and the primary variable is changed at a predetermined value for each cycle of change of the secondary variable. A sequence that changes as much as an incremental value determined according to the resolution.
또는 본 발명의 일 실시예에 의하면, 각도(
Figure PCTKR2020006441-appb-I000016
)를 고정하고 반경(r)을 변화시킨 뒤, 반경에 따른 반사광 측정이 끝나면, 각도(
Figure PCTKR2020006441-appb-I000017
)를 변화시키고 반경(r)을 변화시키면서 반사광 측정을 수행할 수도 있다(도 16). 즉, 극좌표계에 따른 측정은 동일하되, 변수를 측정하는 순서가 바뀔 수 있다.
Or according to an embodiment of the present invention, the angle (
Figure PCTKR2020006441-appb-I000016
) Is fixed and the radius (r) is changed. After measuring the reflected light according to the radius, the angle (
Figure PCTKR2020006441-appb-I000017
It is also possible to perform reflected light measurement while changing) and changing the radius r (FIG. 16). That is, the measurement according to the polar coordinate system is the same, but the order of measuring the variable may be changed.
위와 같은 반사광의 측정은 다음과 같은 시퀀스를 통해 구현될 수 있다: 상기 대물렌즈의 후방 초점 면에서 렌즈 중심축을 원점으로 하는 극좌표계에 대하여, 각도 값을 1차 변수, 반경 값을 2차 변수로 두고, 2차 변수를 미리 정해진 값에서 상기 공간 광 변조기의 해상도에 따라 정해지는 변화값 만큼 변화시키고, 각 2차 변수의 변화 사이클마다 1차 변수를 0도 내지 360도에서 변화시키는 시퀀스.The measurement of the reflected light as described above can be implemented through the following sequence: For a polar coordinate system with the lens center axis as the origin at the rear focal plane of the objective lens, the angle value is the primary variable and the radius value is the secondary variable. And changing a secondary variable by a change value determined according to the resolution of the spatial light modulator at a predetermined value, and changing the primary variable from 0 degrees to 360 degrees for each change cycle of each secondary variable.
이와 같은 과정을 반복하면, 광학계가 허용하는 한도 내에서 다양한 입사각(θ)에 대하여 다양한 편광 성분에 대한 시료(300)의 반응, 즉 rp, rs 값을 구할 수 있으며, 이로부터 전술한 과정을 거쳐 다양한 물성을 측정할 수 있다.By repeating this process, the reaction of the sample 300 to various polarization components for various angles of incidence (θ) within the limit allowed by the optical system, that is, r p and r s values can be obtained, from which the above-described process Various physical properties can be measured through
본 발명의 또다른 실시예에 따르면, 공간 광 변조기(120)에 대하여, 전술한 극좌표계에 따른 각도를 1차 변수, 반경을 2차 변수로 하는 시퀀스 대신, 다른 시퀀스를 사용하여 측정을 수행할 수 있다. According to another embodiment of the present invention, for the spatial light modulator 120, instead of a sequence in which an angle according to the polar coordinate system is a primary variable and a radius is a secondary variable, a measurement can be performed using another sequence. I can.
예컨대 공간 광 변조기(120)의 화소는 극좌표계가 아닌 카테시안 좌표계로 구성될 수 있으므로, 광선이 대물 렌즈(150)의 중심축에 대하여 일정한 반경을 그리기보다는 각 화소를 행-렬 순서대로, 즉, 1행의 1열부터 마지막 열까지, 2행의 1열부터 마지막 열까지, ...와 같이 이어지는 형태로 시퀀스를 구성할 수 있다(도 17). 이 때 마지막 열과 마지막 행은 공간 광 변조기(120)를 구성하는 화소의 어레이의 가로 및 세로 해상도에 따라 결정될 수 있다. 전술한 극좌표계에서와 마찬가지로 각 행-렬을 스윕(sweep)하는 방향은 달라질 수 있다. 예컨대 마지막 행부터 1행까지 및/또는 마지막 열부터 1열까지 이어지는 형태로 시퀀스를 구성할 수도 있다.For example, since the pixels of the spatial light modulator 120 may be composed of a Cartesian coordinate system instead of a polar coordinate system, rather than drawing a constant radius with respect to the central axis of the objective lens 150, each pixel is arranged in a row-column order, that is, A sequence can be configured in a continuous manner, such as from column 1 to the last column of row 1, column 1 to last column of row 2, ... (FIG. 17). At this time, the last column and the last row may be determined according to the horizontal and vertical resolution of the array of pixels constituting the spatial light modulator 120. As in the above-described polar coordinate system, the direction of sweeping each row-column may be different. For example, a sequence may be formed in a form that continues from the last row to the first row and/or from the last column to the first column.
구체적으로는 위 방식에 따른 반사광의 측정은 다음과 같은 시퀀스를 통해 구현될 수 있다: 상기 대물렌즈의 후방 초점 면에서 대물 렌즈의 중심축을 원점으로 하는 카테시안 좌표계에 대하여, 행을 1차 변수, 열을 2차 변수로 두고, 2차 변수를 1열에서 상기 하나 이상의 화소의 어레이의 열 수 사이에서 변화시키고, 각 2차 변수의 변화 사이클마다 1차 변수를 1행에서 상기 하나 이상의 화소의 어레이의 행 수 사이에서 변화시키는 시퀀스.Specifically, the measurement of reflected light according to the above method can be implemented through the following sequence: For a Cartesian coordinate system whose origin is the central axis of the objective lens at the rear focal plane of the objective lens, the row is the primary variable, With a column as a secondary variable, a secondary variable is changed between the number of columns of the array of one or more pixels in column 1, and the primary variable is an array of the one or more pixels in row 1 for each change cycle of the secondary variable A sequence that changes between the number of rows of.
이 대안적인 시퀀스는 예컨대 브라운관 TV의 전자총이 주사되는 것과 유사하게 좌상단부터 가로줄을 그리면서 우하단으로 이어지는 시퀀스일 수 있으며, 공간 광 변조기(120)의 각 화소의 제어 신호가 입력되는 것과 동일한 순서일 수 있기 때문에, 시퀀스의 코딩이 더 간단하다는 장점이 있다. 다만 극좌표계에 따른 시퀀스에 비하면 각 측정값의 순서와 입사각, 편광 상태와의 연관성이 없이 섞여 있기 때문에, 측정 후에 이를 재정렬하여 입사각과 편광 상태에 따른 데이터로 정리해 주어야 한다.This alternative sequence may be, for example, a sequence from the top left to the bottom right while drawing a horizontal line, similar to the scanning of an electron gun of a CRT TV, and the same sequence as the control signal of each pixel of the spatial light modulator 120 is input. Because it can, there is an advantage that the coding of the sequence is simpler. However, compared to the sequence according to the polar coordinate system, the order of each measurement value, the incident angle, and the polarization state are mixed without being correlated. Therefore, after the measurement, it is necessary to rearrange the data according to the incident angle and the polarization state.
이상에서 설명한 시퀀스는 어디까지나 예시적인 것이며, 당업자는 사용하려는 광학계의 광학적 구성, 측정하려는 시료의 특성, 광학계의 구성에 사용된 장비의 특성, 조사광에 의한 시료의 특정 부위의 과열, 측정되는 데이터의 계산을 위한 최적화 등을 고려하여 다양한 좌표계와 순서에 따른 시퀀스를 고안할 수 있으며, 이러한 변형가능성은 본 발명의 범위에 포함되는 것이다.The sequence described above is only illustrative, and those skilled in the art are concerned with the optical configuration of the optical system to be used, the characteristics of the sample to be measured, the characteristics of the equipment used for the configuration of the optical system, overheating of a specific part of the sample by irradiation light, and the measured data. It is possible to devise a sequence according to various coordinate systems and sequences in consideration of optimization for calculation of, and such variations are included within the scope of the present invention.
위에서 설명한, 본 발명의 일 실시예에 의한 광학계에 의한 물성 측정 방법은, 입사광의 편광 성분을 변화시켜 주기 위하여 편광상태생성기 혹은 편광상태분석기 상의 적어도 하나의 광학 소자를 수동으로 또는 기계적으로 움직여 주어야 했던 종래의 기술에 비해, 물리 진동을 발생시키지 않으면서 광학계의 운용이 가능해진다는 장점을 가진다. 공간 광 변조기(120) 내에 포함된 화소의 기계적 움직임은 있을 수 있으나, 이것으로 인한 진동은 실질적으로 감지하기 어려운 수준으로 작다. 때문에, 진동으로 인한 잡음이 감소하며 측정값의 신뢰성이 향상된다.As described above, in the method of measuring physical properties by an optical system according to an embodiment of the present invention, in order to change the polarization component of incident light, at least one optical element on the polarization state generator or the polarization state analyzer has to be manually or mechanically moved. Compared with the conventional technology, it has an advantage that the optical system can be operated without generating physical vibration. Although there may be a mechanical movement of the pixels included in the spatial light modulator 120, the vibration caused by this is substantially small to a level that is difficult to detect. Therefore, noise due to vibration is reduced and the reliability of the measured value is improved.
본 발명의 일 실시예에 의한 광학계에 의한 물성 측정 방법의 또다른 장점은 전술한 공간 광 변조기(120)에서 특정 화소의 온/오프는 외부에 연결된 컴퓨터 등의 전자기기를 통하여 사실상 자동화된 시퀀스로 가능하기 때문에, 이전의 수동 조작 또는 기계적 조작에 비해 더 빠르고 편리한 측정이 가능하다는 점이다. 즉 전술한 후방 초점 면(200) 상의 빛의 위치 이동은 공간 광 변조기(120)에서 온(on)될 픽셀을 지정하는 시퀀스를 코딩하는 것만으로 컴퓨터에 의해 자동화 될 수 있으며, 이 시퀀스는 미리 프로그래밍된 것을 사용할 수도 있다. 따라서 사용자의 직접 조작 필요성이 현저히 줄어든다.Another advantage of the method for measuring physical properties by an optical system according to an embodiment of the present invention is that the on/off of a specific pixel in the spatial light modulator 120 described above is performed in a virtually automated sequence through an electronic device such as a computer connected to the outside. Because of this, faster and more convenient measurements are possible compared to previous manual or mechanical operation. That is, the movement of the position of light on the above-described rear focal plane 200 can be automated by a computer simply by coding a sequence specifying a pixel to be turned on by the spatial light modulator 120, and this sequence is preprogrammed. You can also use the old one. Therefore, the need for direct manipulation by the user is significantly reduced.
또한 기존의 타원편광 현미경의 장점, 즉, 높은 측면 해상도와 고해상도 이미징이 가능한 장점은 본 발명에서 그대로 유지된다.In addition, the advantages of the existing elliptic polarization microscope, that is, the advantages of high lateral resolution and high resolution imaging are maintained in the present invention.
여기서는 본 발명의 실시예들에 의한 광학계 및 이를 이용한 물성 측정 방법만을 설명하였지만, 당업자라면 본 발명을 사용하여 다양한 응용방법을 구현할 수 있으며, 이는 모두 본 발명의 범위에 포함되는 것이다.Herein, only the optical system according to the embodiments of the present invention and a method for measuring physical properties using the same have been described, but those skilled in the art can implement various application methods using the present invention, all of which are included in the scope of the present invention.
상기에서는 본 발명의 바람직한 실시예를 참조하여 설명하였지만, 해당 기술분야의 숙련된 당업자는 하기의 특허 청구 범위에 기재된 본 발명의 사상 및 영역으로부터 벗어나지 않는 범위 내에서 본 발명을 다양하게 수정 및 변경시킬 수 있음을 이해할 수 있을 것이다.Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the present invention described in the following claims. You will understand that you can.
본 발명에 따른 공간 광 변조기를 이용한 광학계를 사용하면 모터의 구동없이 자동화된 시료의 물성 측정을 할 수 있으며, 기계적 조작으로 인한 노이즈의 개입 가능성이 감소되기 때문에 더 정확하고 빠른 측정이 가능해진다. 또한 종래의 타원편광 현미경이 가졌던 장점, 즉 높은 측면 해상도와 고해상도 이미징이 가능하다는 장점은 본 발명에 따른 광학계에서도 그대로 유지된다.When the optical system using the spatial light modulator according to the present invention is used, it is possible to measure the physical properties of a sample without driving a motor, and since the possibility of interference of noise due to mechanical manipulation is reduced, more accurate and fast measurement is possible. In addition, the advantages of the conventional elliptical polarization microscope, that is, the advantages of high lateral resolution and high resolution imaging are maintained in the optical system according to the present invention.

Claims (27)

  1. 시료의 물성을 측정하기 위한 광학계로서, 상기 광학계는,As an optical system for measuring the physical properties of a sample, the optical system,
    광원으로부터 수신된 빛에 대하여 빛의 빔-단면을 미리 정해진 제1 이미지(image)의 모양으로 변조하는 공간 광 변조기(spatial light modulator, SLM);A spatial light modulator (SLM) for modulating a beam-section of light into a shape of a first predetermined image with respect to the light received from the light source;
    상기 공간 광 변조기에 의해 변조된 빛을 수신하여, 미리 정해진 제1 편광 상태로 변환하는, 편광상태생성기(polarization state generator, PSG);A polarization state generator (PSG) for receiving the light modulated by the spatial light modulator and converting it into a first predetermined polarization state;
    상기 제1 편광 상태로 변환된 빛을 수신하여 시료에 입사시키고, 상기 시료로부터 반사되어 나온 빛을 수신하는, 대물렌즈(object lens);An object lens for receiving the light converted into the first polarization state, making it incident on a sample, and receiving light reflected from the sample;
    상기 시료로부터 반사되어 상기 대물렌즈에 수신되어 상기 대물렌즈를 통과한 빛을 수신하여, 미리 정해진 제2 편광 상태로 변환하는, 편광상태분석기(polarization state analyzer, PSA);A polarization state analyzer (PSA) that is reflected from the sample and received by the objective lens to receive light that has passed through the objective lens and converts it into a second predetermined polarization state;
    상기 제2 편광 상태로 변환된 빛을 수신하여 전기 신호로 변환하는, 광감지기(photodetector);A photodetector for receiving the light converted into the second polarization state and converting it into an electric signal;
    를 포함하는, 시료의 물성을 측정하기 위한 광학계.Containing, an optical system for measuring the physical properties of the sample.
  2. 제1항에 있어서,The method of claim 1,
    상기 광학계는 상기 대물렌즈의 후방 초점 면(back focal plane)에 미리 정해진 제2 이미지가 맺히게 하는 것을 특징으로 하는, 시료의 물성을 측정하기 위한 광학계.The optical system for measuring physical properties of a sample, characterized in that the second image is formed on a back focal plane of the objective lens.
  3. 제2항에 있어서,The method of claim 2,
    상기 편광상태생성기와 상기 편광상태분석기 각각은, 편광자(polarizer), 보상기(compensator), 위상 변조기(phase modulator), 파장변조필터(wavelength modulation filter) 중 어느 하나 또는 그 이상을 포함하고,Each of the polarization state generator and the polarization state analyzer includes one or more of a polarizer, a compensator, a phase modulator, and a wavelength modulation filter,
    상기 광학계는, 릴레이 렌즈(relay lens), 접안 렌즈(eyepiece), 빔 스플리터(beam splitter) 중 어느 하나 또는 그 이상을 포함하는,The optical system includes any one or more of a relay lens, an eyepiece, and a beam splitter,
    시료의 물성을 측정하기 위한 광학계.Optical system for measuring the physical properties of samples.
  4. 제3항에 있어서,The method of claim 3,
    상기 공간 광 변조기는 하나 이상의 디지털 마이크로미러 장치(digital micromirror device, DMD)의 어레이(array)이고, 상기 디지털 마이크로미러 장치는 상부에 빛을 반사하는 금속, 비금속, 유리 어느 하나 또는 그 이상의 재질로 구성된 반사경(reflective mirro)과 상기 반사경의 하부에 연결된 힌지(hinge)를 포함하고, 상기 디지털 마이크로미러 장치는 외부에서 주어진 신호에 따라 힌지에 전압을 인가하여 상기 반사경을 휘게 함으로써 상기 공간 광 변조기에 입사된 빛 중 상기 디지털 마이크로미러 장치에 입사된 빛의 변조를 조절하는, 시료의 물성을 측정하기 위한 광학계.The spatial light modulator is an array of one or more digital micromirror devices (DMD), and the digital micromirror device is made of any one or more materials of metal, non-metal, and glass that reflect light on the top. It includes a reflective mirro and a hinge connected to a lower portion of the reflective mirror, and the digital micromirror device applies a voltage to the hinge according to a signal given from the outside to bend the reflector to be incident on the spatial light modulator. An optical system for measuring physical properties of a sample, controlling modulation of light incident on the digital micromirror device among light.
  5. 제3항에 있어서,The method of claim 3,
    상기 공간 광 변조기는 하나 이상의 LCoS(Liquid Cell on Silicon) 소자의 어레이이고, 상기 LCoS 소자는 액정, 전극, 수신측 편광판, 반사측 편광판을 포함하고, 상기 LCoS 소자는 외부에서 주어진 신호에 따라 상기 전극을 통해 상기 액정에 전압을 인가하여 상기 액정의 구조를 변화시킴으로써 상기 공간 광 변조기에 입사된 빛 중 상기 LCoS 소자에 입사된 빛의 변조를 조절하는, 시료의 물성을 측정하기 위한 광학계.The spatial light modulator is an array of one or more LCoS (Liquid Cell on Silicon) devices, the LCoS device includes a liquid crystal, an electrode, a receiving-side polarizing plate, and a reflecting-side polarizing plate, and the LCoS device is the electrode according to an externally given signal. An optical system for measuring physical properties of a sample for controlling modulation of light incident on the LCoS element among the light incident on the spatial light modulator by applying a voltage to the liquid crystal by changing the structure of the liquid crystal.
  6. 제3항에 있어서,The method of claim 3,
    상기 공간 광 변조기는 하나 이상의 투과형 LC(Liquid Crystal) 소자의 어레이이고, 상기 투과형 LC 소자는 액정, 전극 및 액정의 양면 쪽에 형성된 투과판을 포함하고, 상기 투과형 LC 소자는 외부에서 주어진 신호에 따라 상기 전극을 통해 상기 액정에 전압을 인가하여 상기 액정의 투과도(transmittivity)를 변화시킴으로써 상기 공간 광 변조기에 입사된 빛 중 상기 투과형 LC 소자에 입사된 빛의 변조를 조절하는, 시료의 물성을 측정하기 위한 광학계.The spatial light modulator is an array of one or more transmissive LC (Liquid Crystal) elements, the transmissive LC element includes a liquid crystal, an electrode, and a transmissive plate formed on both sides of the liquid crystal, and the transmissive LC element includes the transmissive LC element according to an externally given signal. By applying a voltage to the liquid crystal through an electrode to change the transmittance of the liquid crystal to adjust the modulation of the light incident on the transmissive LC element among the light incident on the spatial light modulator, Optical system.
  7. 제4항 내지 제6항 중 어느 한 항에 있어서,The method according to any one of claims 4 to 6,
    상기 어레이는 2차원 사각형 어레이(2-dimensional rectangular array) 또는 2차원 원형 어레이(2-dimensional circular array)의 형태인, 시료의 물성을 측정하기 위한 광학계.The array is in the form of a 2-dimensional rectangular array or a 2-dimensional circular array, an optical system for measuring physical properties of a sample.
  8. 제4항 내지 제6항 중 어느 한 항에 있어서,The method according to any one of claims 4 to 6,
    상기 공간 광 변조기는 상기 어레이를 구성하는 각 개체에 대하여 빛을 반사하거나 반사하지 않는 상태를 지정하는 미리 정해진 시퀀스(sequence)에 따라 각 개체의 빛을 반사하거나 반사하지 않는, 시료의 물성을 측정하기 위한 광학계.The spatial light modulator measures the physical properties of the sample, reflecting or not reflecting light of each object according to a predetermined sequence that specifies a state of reflecting or not reflecting light for each object constituting the array. Optical system.
  9. 제8항에 있어서,The method of claim 8,
    상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 렌즈 중심축을 원점으로 하는 극좌표계에 대하여, 반경(radius) 값을 1차 변수, 각도(radian) 값을 2차 변수로 두고, 2차 변수를 0도 내지 360도 범위에서 변화시키고, 각 2차 변수의 주기마다 1차 변수의 값을 미리 정해진 시작값에서 상기 공간 광 변조기의 상기 어레이의 해상도에 따라 정해지는 변화값 만큼 변화시키는 것에 대응하는, 시료의 물성을 측정하기 위한 광학계.In the above sequence, for a polar coordinate system with a lens center axis as the origin at the rear focal plane of the objective lens, a radius value is set as a primary variable, an angle value is set as a secondary variable, and a secondary variable is 0 degrees. To 360 degrees, and corresponding to changing the value of the primary variable for each period of the secondary variable by a change value determined according to the resolution of the array of the spatial light modulator at a predetermined starting value. Optical system for measuring physical properties.
  10. 제8항에 있어서,The method of claim 8,
    상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 렌즈 중심축을 원점으로 하는 극좌표계에 대하여, 각도 값을 1차 변수, 반경 값을 2차 변수로 두고, 2차 변수를 미리 정해진 시작값에서 상기 공간 광 변조기의 상기 어레이의 해상도에 따라 정해지는 변화값만큼 변화시키고, 각 2차 변수의 주기마다 1차 변수를 0도 내지 360도 범위에서 변화시키는 것에 대응하는, 시료의 물성을 측정하기 위한 광학계.The sequence includes an angle value as a primary variable and a radius value as a secondary variable for a polar coordinate system with a lens center axis as an origin at a rear focal plane of the objective lens, and a secondary variable is the spatial light at a predetermined starting value. An optical system for measuring physical properties of a sample, corresponding to varying by a change value determined according to the resolution of the array of the modulator, and changing the primary variable in the range of 0 degrees to 360 degrees for each period of the secondary variable.
  11. 제8항에 있어서,The method of claim 8,
    상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 대물 렌즈의 중심축을 원점으로 하는 카테시안 좌표계(Cartesian coordinate system)에 대하여, 행(row)을 1차 변수, 열(column)을 2차 변수로 두고, 2차 변수를 미리 정해진 제2 시작값에서 상기 공간 광 변조기의 상기 어레이의 가로 해상도에 따라 정해지는 변화값만큼 변화시키고, 각 2차 변수의 주기마다 1차 변수를 미리 정해진 제1 시작값에서 상기 공간 광 변조기의 상기 어레이의 세로 해상도에 따라 정해지는 변화값만큼 변화시키는 것에 대응하는, 시료의 물성을 측정하기 위한 광학계.In the sequence, for a Cartesian coordinate system in which the central axis of the objective lens is the origin at the rear focal plane of the objective lens, a row is a primary variable and a column is a secondary variable, The secondary variable is changed from a second predetermined start value by a change value determined according to the horizontal resolution of the array of the spatial light modulator, and the primary variable is changed from the first predetermined start value to the cycle of each secondary variable. An optical system for measuring physical properties of a sample, corresponding to changing by a change value determined according to the vertical resolution of the array of the spatial light modulator.
  12. 제8항에 있어서,The method of claim 8,
    상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 대물 렌즈의 중심축을 원점으로 하는 카테시안 좌표계(Cartesian coordinate system)에 대하여, 열(column)을 1차 변수, 행(row)을 2차 변수로 두고, 2차 변수를 미리 정해진 제2 시작값에서 상기 공간 광 변조기의 상기 어레이의 세로 해상도에 따라 정해지는 변화값만큼 변화시키고, 각 2차 변수의 주기마다 1차 변수를 미리 정해진 제1 시작값에서 상기 공간 광 변조기의 상기 어레이의 가로 해상도에 따라 정해지는 변화값만큼 변화시키는 것에 대응하는, 시료의 물성을 측정하기 위한 광학계.The sequence has a column as a primary variable and a row as a secondary variable for a Cartesian coordinate system in which the central axis of the objective lens is an origin at the rear focal plane of the objective lens, The secondary variable is changed by a change value determined according to the vertical resolution of the array of the spatial light modulator from the second predetermined start value, and the primary variable is changed from the predetermined first start value for each period of each secondary variable. An optical system for measuring physical properties of a sample, corresponding to changing by a change value determined according to the horizontal resolution of the array of the spatial light modulator.
  13. 광학계를 사용하여 시료의 물성을 측정하는 방법으로서, 상기 방법은,As a method of measuring the physical properties of a sample using an optical system, the method,
    공간 광 변조기가 광원으로부터 수신된 빛의 빔-단면을 미리 정해진 제1 이미지의 모양으로 변조하는 단계(S10);Modulating, by the spatial light modulator, the beam-section of light received from the light source into a shape of a first predetermined image (S10);
    편광상태생성기가 상기 공간 광 변조기에 의해 변조된 빛을 수신하여, 미리 정해진 제1 편광 상태로 변환하는 단계(S20);Receiving, by a polarization state generator, the light modulated by the spatial light modulator and converting the light into a first predetermined polarization state (S20);
    대물렌즈가 상기 제1 편광 상태로 변환된 빛을 수신하여 시료에 입사시키는 단계(S30);Receiving, by the objective lens, the light converted to the first polarization state and causing it to enter the sample (S30);
    대물렌즈가 상기 시료로부터 반사되어 나온 빛을 수신하는 단계(S40);Receiving the light reflected from the sample by the objective lens (S40);
    편광상태분석기가 상기 시료로부터 반사되어 상기 대물렌즈에 수신되어 상기 대물렌즈를 통과한 빛을 수신하여, 미리 정해진 제2 편광 상태로 변환하는 단계(S50);A step (S50) of a polarization state analyzer receiving light reflected from the sample and received by the objective lens and passing through the objective lens, and converting the light into a second predetermined polarization state (S50);
    광감지기가 상기 제2 편광 상태로 변환된 빛을 수신하여 전기 신호로 변환하는 단계(S60);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하는 방법.A method for measuring physical properties of a sample using an optical system, comprising; receiving the light converted into the second polarization state and converting it into an electrical signal (S60).
  14. 제13항에 있어서,The method of claim 13,
    상기 단계 (S30)은 상기 대물렌즈의 후방 초점 면에 미리 정해진 제2 이미지가 맺히게 하는 단계(S31);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하는 방법.The step (S30) includes a step (S31) of causing a second predetermined image to be formed on the rear focal plane of the objective lens. Including, a method of measuring physical properties of a sample using an optical system.
  15. 제14항에 있어서,The method of claim 14,
    상기 공간 광 변조기는 하나 이상의 디지털 마이크로미러 장치의 어레이이고, 상기 디지털 마이크로미러 장치는 상부에 빛을 반사하는 금속, 비금속, 유리 어느 하나 또는 그 이상의 재질로 구성된 반사경과 상기 반사경의 하부에 연결된 힌지를 포함하고,The spatial light modulator is an array of one or more digital micromirror devices, and the digital micromirror device includes a reflector made of one or more materials of metal, non-metal, and glass that reflects light on the top and a hinge connected to the bottom of the reflector. Including,
    상기 단계 (S10)은 상기 디지털 마이크로미러 장치가 외부에서 주어진 신호에 따라 힌지에 전압을 인가하여 상기 반사경을 휘게 함으로써 상기 공간 광 변조기에 입사된 빛 중 상기 디지털 마이크로미러 장치에 입사된 빛의 변조를 조절하는 단계(S11);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하는 방법.In the step (S10), the digital micromirror device applies a voltage to the hinge according to an externally given signal to bend the reflector, thereby modulating the light incident on the digital micromirror device among the light incident on the spatial light modulator. A method for measuring physical properties of a sample using an optical system, including; adjusting (S11).
  16. 제14항에 있어서,The method of claim 14,
    상기 공간 광 변조기는 하나 이상의 LCoS 소자의 어레이이고, 상기 LCoS 소자는 액정, 전극, 수신측 편광판, 반사측 편광판을 포함하고, The spatial light modulator is an array of one or more LCoS elements, and the LCoS element includes a liquid crystal, an electrode, a receiving side polarizing plate, and a reflecting side polarizing plate,
    상기 단계 (S10)은 상기 LCoS 소자가 외부에서 주어진 신호에 따라 상기 전극을 통해 상기 액정에 전압을 인가하여 상기 액정의 구조를 변화시킴으로써 상기 공간 광 변조기에 입사된 빛 중 상기 LCoS 소자에 입사된 빛의 변조를 조절하는 단계(S12);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하는 방법.In the step (S10), the LCoS element changes the structure of the liquid crystal by applying a voltage to the liquid crystal through the electrode according to an externally given signal, so that the light incident on the LCoS element among the light incident on the spatial light modulator. Adjusting the modulation of (S12); comprising, a method of measuring the physical properties of the sample using an optical system.
  17. 제14항에 있어서,The method of claim 14,
    상기 공간 광 변조기는 하나 이상의 투과형 LC 소자의 어레이이고, 상기 투과형 LC 소자는 액정, 전극 및 액정의 양면 쪽에 형성된 투과판을 포함하고, The spatial light modulator is an array of one or more transmissive LC elements, and the transmissive LC element includes a liquid crystal, an electrode, and a transmissive plate formed on both sides of the liquid crystal,
    상기 단계 (S10)은 상기 투과형 LC 소자는 외부에서 주어진 신호에 따라 상기 전극을 통해 상기 액정에 전압을 인가하여 상기 액정의 투과도를 변화시킴으로써 상기 공간 광 변조기에 입사된 빛 중 상기 투과형 LC 소자에 입사된 빛의 변조를 조절하는 단계(S13);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.In the step (S10), the transmissive LC element is incident on the transmissive LC element among the light incident on the spatial light modulator by changing the transmittance of the liquid crystal by applying a voltage to the liquid crystal through the electrode according to an externally given signal. A method for measuring physical properties of a sample using an optical system comprising; controlling the modulation of the light (S13).
  18. 제15항 내지 제17항 중 어느 한 항에 있어서,The method according to any one of claims 15 to 17,
    상기 단계 (S10)은 상기 공간 광 변조기가 2차원 사각형 어레이 또는 2차원 원형 어레이의 형태로 상기 수신된 빛의 빔-단면을 미리 정해진 제1 이미지의 모양으로 변조하는 단계(S14);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.In the step (S10), the spatial light modulator modulates the beam-section of the received light in the form of a two-dimensional rectangular array or a two-dimensional circular array (S14) into a shape of a predetermined first image; including , Method for measuring the physical properties of a sample using an optical system.
  19. 제15항 내지 제17항 중 어느 한 항에 있어서,The method according to any one of claims 15 to 17,
    상기 단계 (S10)은 상기 공간 광 변조기가 상기 어레이를 구성하는 각 개체에 대하여 빛을 반사하거나 반사하지 않는 상태를 지정하는 미리 정해진 시퀀스에 따라 각 개체의 빛을 반사하거나 반사하지 않는 단계(S15);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.The step (S10) is a step of reflecting or not reflecting light of each object according to a predetermined sequence in which the spatial light modulator reflects or does not reflect light for each object constituting the array (S15) A method for measuring physical properties of a sample using an optical system including;
  20. 제19항에 있어서,The method of claim 19,
    상기 단계 (S15)에서 상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 렌즈 중심축을 원점으로 하는 극좌표계에 대하여, 반경 값을 1차 변수, 각도 값을 2차 변수로 두고, 2차 변수를 0도 내지 360도 범위에서 변화시키고, 각 2차 변수의 주기마다 1차 변수의 값을 미리 정해진 시작값에서 상기 공간 광 변조기의 상기 어레이의 해상도에 따라 정해지는 변화값 만큼 변화시키는 것에 대응하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.In the step (S15), the sequence is a polar coordinate system with a lens center axis as an origin at the rear focal plane of the objective lens, with a radius value as a primary variable, an angle value as a secondary variable, and a secondary variable at 0 degrees. To 360 degrees, and corresponding to changing the value of the primary variable for each period of the secondary variable by a change value determined according to the resolution of the array of the spatial light modulator at a predetermined starting value. Method for measuring the physical properties of a sample by using.
  21. 제19항에 있어서,The method of claim 19,
    상기 단계 (S15)에서 상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 렌즈 중심축을 원점으로 하는 극좌표계에 대하여, 각도 값을 1차 변수, 반경 값을 2차 변수로 두고, 2차 변수를 미리 정해진 시작값에서 상기 공간 광 변조기의 상기 어레이의 해상도에 따라 정해지는 변화값만큼 변화시키고, 각 2차 변수의 주기마다 1차 변수를 0도 내지 360도 범위에서 변화시키는 것에 대응하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.In the step (S15), the sequence is a polar coordinate system having a lens center axis as an origin at the rear focal plane of the objective lens, with an angle value as a primary variable and a radius value as a secondary variable, and a secondary variable is predetermined. Using an optical system, corresponding to changing the starting value by a change value determined according to the resolution of the array of the spatial light modulator, and changing the primary variable in the range of 0 degrees to 360 degrees for each secondary variable period. A method for measuring the physical properties of a sample.
  22. 제19항에 있어서,The method of claim 19,
    상기 단계 (S15)에서 상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 대물 렌즈의 중심축을 원점으로 하는 카테시안 좌표계(Cartesian coordinate system)에 대하여, 행(row)을 1차 변수, 열(column)을 2차 변수로 두고, 2차 변수를 미리 정해진 제2 시작값에서 상기 공간 광 변조기의 상기 어레이의 가로 해상도에 따라 정해지는 변화값만큼 변화시키고, 각 2차 변수의 주기마다 1차 변수를 미리 정해진 제1 시작값에서 상기 공간 광 변조기의 상기 어레이의 세로 해상도에 따라 정해지는 변화값만큼 변화시키는 것에 대응하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.In the step (S15), the sequence is a Cartesian coordinate system whose origin is the central axis of the objective lens at the rear focal plane of the objective lens, with a row as a primary variable and a column. As a secondary variable, the secondary variable is changed by a change value determined according to the horizontal resolution of the array of the spatial light modulator at a predetermined second starting value, and the primary variable is predetermined for each secondary variable period. A method for measuring physical properties of a sample using an optical system, corresponding to changing a first starting value by a change value determined according to the vertical resolution of the array of the spatial light modulator.
  23. 제19항에 있어서,The method of claim 19,
    상기 단계 (S15)에서 상기 시퀀스는 상기 대물렌즈의 후방 초점 면에서 대물 렌즈의 중심축을 원점으로 하는 카테시안 좌표계(Cartesian coordinate system)에 대하여, 열(column)을 1차 변수, 행(row)을 2차 변수로 두고, 2차 변수를 미리 정해진 제2 시작값에서 상기 공간 광 변조기의 상기 어레이의 세로 해상도에 따라 정해지는 변화값만큼 변화시키고, 각 2차 변수의 주기마다 1차 변수를 미리 정해진 제1 시작값에서 상기 공간 광 변조기의 상기 어레이의 가로 해상도에 따라 정해지는 변화값만큼 변화시키는 것에 대응하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.In the step (S15), the sequence is a Cartesian coordinate system whose origin is the central axis of the objective lens at the rear focal plane of the objective lens, with a column as a primary variable and a row. As a secondary variable, the secondary variable is changed by a change value determined according to the vertical resolution of the array of the spatial light modulator at a predetermined second starting value, and the primary variable is predetermined for each secondary variable period. A method for measuring physical properties of a sample using an optical system, corresponding to changing a first starting value by a change value determined according to a horizontal resolution of the array of the spatial light modulator.
  24. 제14항에 있어서,The method of claim 14,
    상기 방법은, 상기 변환된 전기 신호의 측정값을 기초로 시료의 물성을 계산하는 단계(S70);를 더 포함하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.The method further comprises calculating physical properties of the sample based on the measured value of the converted electrical signal (S70). A method for measuring physical properties of the sample using an optical system.
  25. 제24항에 있어서,The method of claim 24,
    상기 단계(S70)는:The step (S70) is:
    상기 변환된 전기 신호의 측정값을 상기 미리 정해진 물리 모델에서 계산된 추정값과 비교하여, 상기 물리 모델의 정합도를 계산하는 단계(S71);Comparing the measured value of the converted electrical signal with an estimated value calculated in the predetermined physical model, and calculating a degree of matching of the physical model (S71);
    상기 정합도의 계산 결과에 따라, 상기 물리 모델을 변경하거나 상기 물리 모델의 변수를 조절하는 단계(S72);Changing the physical model or adjusting variables of the physical model according to the calculation result of the degree of matching (S72);
    상기 단계 (S10) 내지 상기 단계 (S72)를 반복하여, 미리 정해진 기준치 이상의 정합도를 가진 물리 모델 및 물리 모델의 변수값을 계산하고, 계산된 물리 모델 및 물리 모델의 변수값에 따라 시료의 물성을 계산하는 단계(S73);를 포함하는, 광학계를 사용하여 시료의 물성을 측정하기 위한 방법.By repeating the steps (S10) to (S72), a physical model having a degree of matching equal to or greater than a predetermined reference value and a variable value of the physical model are calculated, and the physical properties of the sample according to the calculated physical model and the variable values of the physical model A method for measuring physical properties of a sample using an optical system comprising; calculating (S73).
  26. 제14항에 있어서,The method of claim 14,
    상기 방법은:The method is:
    단계 (S10) 이전에, 광원에서 빛이 생성되어 상기 공간 광 변조기로 입사하는 단계(S09);Before step (S10), light is generated from a light source and incident on the spatial light modulator (S09);
    단계 (S20)과 단계 (S30) 사이에, 빔 스플리터가 상기 제1 편광 상태로 변환된 빛을 수신하여 상기 대물렌즈에 입사시키는 단계(S25);Between steps (S20) and (S30), a beam splitter receives the light converted to the first polarization state and makes it incident on the objective lens (S25);
    단계 (S40)과 단계 (S50) 사이에, 빔 스플리터가 상기 대물렌즈에 수신되고 상기 대물렌즈를 통과한 상기 시료로부터 반사된 빛을 수신하여, 상기 편광상태분석기로 입사시키는 단계(S45);를 더 포함하는, 타원편광 현미경을 사용하여 시료의 물성을 측정하는 방법.Between step (S40) and step (S50), a beam splitter is received by the objective lens and the reflected light from the sample that has passed through the objective lens is received and incident to the polarization state analyzer (S45). A method of measuring the physical properties of the sample using an elliptic polarization microscope, further comprising.
  27. 제14항에 있어서, The method of claim 14,
    상기 방법은:The method is:
    단계 (S10)과 단계 (S20) 사이에, 둘 또는 그 이상의 릴레이 렌즈가 상기 공간 광 변조기로부터 반사된 빛을 수신하여, 상기 편광상태생성기로 입사시키는 단계(S15);Between steps (S10) and (S20), two or more relay lenses receive the light reflected from the spatial light modulator and enter the polarization state generator (S15);
    단계 (S50)과 단계 (S60) 사이에, 접안렌즈가 상기 제2 편광 상태로 변환된 빛을 수신하여, 상기 광감지기로 입사시키는 단계(S55);를 더 포함하는, 타원편광 현미경을 사용하여 시료의 물성을 측정하는 방법.Between the step (S50) and step (S60), the eyepiece receives the light converted to the second polarization state, the step (S55) to enter the light detector; using an elliptical polarization microscope A method of measuring the physical properties of a sample.
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