JP2017067982A - Modulator evaluation method and modulator evaluation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire distributions of reflection rate and the like of a spatial light modulator with high accuracy and in a short time.SOLUTION: A modulator evaluation device 1 comprises a first detection unit 41 in which a plurality of light receiving elements are arranged and which receives light passing through a plurality of modulation elements of a spatial light modulator 9, and collectively acquires a first light intensity distribution. A second detection unit 42 arranged in a position optically equivalent to a first detection unit 41 and including a plurality of light receiving elements arranged therein, receives light not passing through the spatial light modulator 9 to collectively acquire a second light intensity distribution. A calculation unit relatively matches the position of the first light intensity distribution with respect to arrangement direction to the second light intensity distribution on the basis of the shapes of the first and second light intensity distributions. A light intensity ratio in each position of the arrangement direction is acquired in the first and second light intensity distributions the relative positions of which are matched to each other. This allows distributions of reflection rate and the like of the plurality of modulation elements of the spatial light modulator to be acquired with high accuracy and in a short time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for evaluating a spatial light modulator.

  Conventionally, a spatial light modulator that spatially modulates irradiated light has been used in a drawing apparatus or the like. For example, in the exposure apparatus of Patent Document 1, a pupil intensity distribution measurement unit having a CCD imaging unit is provided adjacent to the wafer stage, and the spatial light modulation unit is controlled based on the measurement result of the pupil intensity distribution measurement unit. .

International Publication No. WO2011 / 077800

  By the way, since the spatial light modulator greatly affects the performance of the drawing apparatus and the like, it is important to evaluate the characteristics of the spatial light modulator. For example, in a reflective spatial light modulator, the reflectance distribution in a plurality of modulation elements is evaluated. In this case, the spatial light modulator and the reference mirror are arranged side by side on the stage, the stage is moved with respect to the irradiation position of the light beam from the illumination system, and a plurality of modulations of the reference mirror and the spatial light modulator are performed. It is conceivable to use a device that sequentially passes the irradiation position through the element. In such an apparatus, the reflected light from the irradiation position is detected by the observation system, and the reflectance of the plurality of modulation elements is obtained. However, since the above method involves moving the stage, it is difficult to obtain the reflectance distribution in the spatial light modulator in a short time. The above-mentioned problem is the same when obtaining the transmittance distribution in a plurality of modulation elements in a transmissive spatial light modulator.

  The present invention has been made in view of the above problems, and an object thereof is to obtain a distribution of reflectance and the like in a plurality of modulation elements of a spatial light modulator with high accuracy and in a short time.

  The invention according to claim 1 is a modulator evaluation method for evaluating a spatial light modulator, wherein the emitted light emitted from the light source unit is first detected via the spatial light modulator arranged at a predetermined position. In the optical system that guides the light, the first state in which the light that has passed through the spatial light modulator is incident on the first detection unit, and the light before being incident on the spatial light modulator is included. A deflecting unit that realizes the second state of being incident on the second detecting unit disposed at a position optically equivalent to the first detecting unit without passing through the spatial light modulator, simultaneously or separately. Provided in the first detection unit, the second arrangement direction in which the plurality of light receiving elements are arranged in the second detection unit, and the predetermined position. The direction in which a plurality of modulation elements are arranged in the spatial light modulator Correspondingly, the modulator evaluation method includes: a) a step of placing a spatial light modulator to be evaluated at the predetermined position; and b) the first detector in the first arrangement direction in the first state. Obtaining a first light intensity distribution; c) obtaining a second light intensity distribution in the second arrangement direction by the second detector in the second state; and d) the first arrangement direction. While aligning the second arrangement direction as the arrangement direction, overlapping the first light intensity distribution and the second light intensity distribution, and based on the shape of the first light intensity distribution and the second light intensity distribution, A step of relatively aligning the position of the first light intensity distribution with respect to the arrangement direction with respect to the second light intensity distribution; and e) the first light intensity distribution and the second light whose relative positions are aligned. In the intensity distribution, the array And a step of determining the ratio of the light intensity at each position of the direction.

  A second aspect of the present invention is the modulator evaluation method according to the first aspect, wherein the step d) includes d1) one light intensity distribution of the first light intensity distribution and the second light intensity distribution. A step of extracting a portion having a predetermined width in the arrangement direction as a target partial distribution in d2) while shifting a position of the predetermined width portion to be extracted as a corresponding partial distribution in the other light intensity distribution in the arrangement direction, A step of obtaining an evaluation value indicating a difference between the shape of the target partial distribution and the shape of the corresponding partial distribution; and d3) based on the evaluation value, the shape of the target partial distribution and the shape of the corresponding partial distribution are the most. A position in the arrangement direction of the corresponding partial distribution at the time of approximation is obtained, and a specific shift amount that is a distance between the position of the corresponding partial distribution and the position of the target partial distribution is used to calculate the position in the arrangement direction. First light And a step of bringing relatively position in degrees distribution with respect to the second light intensity distribution.

  The invention according to claim 3 is the modulator evaluation method according to claim 2, wherein a plurality of attention partial distributions are extracted in the step d1), and the step d2) includes the plurality of attention partial distributions. In the step d3), the position of the first light intensity distribution with respect to the arrangement direction is set to the second position using a plurality of specific shift amounts obtained for the plurality of target partial distributions. Relative to the light intensity distribution.

  A fourth aspect of the present invention is the modulator evaluation method according to any one of the first to third aspects, wherein the optical system is arranged in a path from the deflection unit to the first detection unit. The configuration of the first partial optical system is the same as the configuration of the second partial optical system disposed on the path from the deflection unit to the second detection unit, except for the spatial light modulator disposed at the predetermined position. It is.

  The invention according to claim 5 is the modulator evaluation method according to any one of claims 1 to 4, wherein the deflecting unit is a beam splitter, and the deflecting unit causes the first state and the first state to be changed. The two states are realized at the same time, and the steps b) and c) are performed simultaneously.

  The invention according to claim 6 is a modulator evaluation method for evaluating a spatial light modulator, and the emitted light emitted from the light source unit is sent to the detection unit via the spatial light modulator arranged at a predetermined position. An arrangement direction in which a plurality of light receiving elements are arranged in the detection unit and a direction in which the plurality of modulation elements are arranged in the spatial light modulator arranged at the predetermined position correspond to each other, The modulator evaluation method includes: a) a step of arranging a spatial light modulator to be evaluated at the predetermined position; b) a step of acquiring a first light intensity distribution in the arrangement direction by the detector; and c) Disposing a reflecting portion at the predetermined position or removing the spatial light modulator; d) obtaining a second light intensity distribution in the arrangement direction by the detecting section; and e) the first light intensity. Distribution and the second light intensity distribution Overlapping and aligning the position of the first light intensity distribution with respect to the arrangement direction relative to the second light intensity distribution based on the shapes of the first light intensity distribution and the second light intensity distribution; F) obtaining a ratio of light intensity at each position in the arrangement direction in the first light intensity distribution and the second light intensity distribution in which the relative positions are matched.

  The invention according to claim 7 is a modulator evaluation device that evaluates a spatial light modulator, a light source unit that emits emitted light, a first detection unit in which a plurality of light receiving elements are arranged in a first arrangement direction, A second detection unit in which a plurality of light receiving elements are arranged in a second arrangement direction, and a first state in which light out of the emitted light that has passed through a spatial light modulator disposed at a predetermined position is incident on the first detection unit And second light that is incident on the second detection unit disposed at an optically equivalent position to the first detection unit without passing through the spatial light modulator without passing through the spatial light modulator. The space arranged at the predetermined position, the first arrangement direction, the second arrangement direction, and an optical system having a deflecting unit that realizes the above state simultaneously or separately. The direction in which the plurality of modulation elements are arranged in the optical modulator corresponds to each other, and the first state In the second state, the first light intensity distribution in the first arrangement direction is acquired by the first detection unit, and the second light intensity distribution in the second arrangement direction is acquired by the second detection unit in the second state, The arithmetic unit overlaps the first light intensity distribution and the second light intensity distribution while aligning the first arrangement direction and the second arrangement direction as the arrangement direction, and the first light intensity distribution and the second light intensity distribution. Based on the shape of the two light intensity distributions, the alignment unit that aligns the position of the first light intensity distribution with respect to the arrangement direction relative to the second light intensity distribution, and the relative position of the alignment unit An intensity ratio calculation unit that obtains a ratio of light intensity at each position in the arrangement direction in the first light intensity distribution and the second light intensity distribution.

  The invention according to claim 8 is the modulator evaluation device according to claim 7, wherein the alignment unit is configured to have the light intensity distribution in one of the first light intensity distribution and the second light intensity distribution. A portion having a predetermined width in the arrangement direction is extracted as a target partial distribution, and the position of the predetermined width portion extracted as a corresponding partial distribution in the other light intensity distribution is shifted in the arrangement direction, and the shape of the target partial distribution is An evaluation value acquisition unit that acquires an evaluation value indicating a difference from the shape of the corresponding partial distribution, and based on the evaluation value, the shape of the target partial distribution and the shape of the corresponding partial distribution are most approximated The position of the corresponding partial distribution in the arrangement direction is obtained, and the first light intensity distribution with respect to the arrangement direction is obtained using a specific shift amount that is a distance between the position of the corresponding partial distribution and the position of the target partial distribution. Position of And a intensity distribution arrangement unit to match relative to the second light intensity distribution.

  The invention according to claim 9 is the modulator evaluation device according to claim 8, wherein the evaluation value acquisition unit extracts a plurality of attention partial distributions, and each of the plurality of attention partial distributions. The position of the first light intensity distribution with respect to the arrangement direction is performed using the plurality of specific shift amounts obtained by the intensity distribution arrangement unit with respect to the plurality of target partial distributions. Is adjusted relative to the second light intensity distribution.

  A tenth aspect of the present invention is the modulator evaluation device according to any one of the seventh to ninth aspects, wherein the optical system is disposed on a path from the deflection unit to the first detection unit. The configuration of the first partial optical system is the same as the configuration of the second partial optical system disposed on the path from the deflection unit to the second detection unit, except for the spatial light modulator disposed at the predetermined position. It is.

  An eleventh aspect of the present invention is the modulator evaluation device according to any one of the seventh to tenth aspects, wherein the deflecting unit is a beam splitter, and the deflecting unit causes the first state and the first state to be changed. 2 is realized simultaneously, and the acquisition of the first light intensity distribution and the acquisition of the second light intensity distribution are performed simultaneously.

  The invention according to claim 12 is a modulator evaluation device for evaluating a spatial light modulator, wherein a light source unit that emits emitted light, a detection unit in which a plurality of light receiving elements are arranged in an arrangement direction, and the emitted light An optical system that leads to the detection unit via a spatial light modulator disposed at a predetermined position, and an arithmetic unit, and a plurality of the spatial light modulators disposed at the predetermined position in the array direction The first light intensity distribution in the arrangement direction is acquired by the detection unit in a state where the direction in which the modulation elements are arranged corresponds to each other and the spatial light modulator to be evaluated is disposed at the predetermined position. Or a second light intensity distribution in the arrangement direction is acquired by the detection unit in a state where the spatial light modulator is removed, and the calculation unit is configured to obtain the first light intensity distribution and the second light intensity. Overlay with distribution Both of the alignment units align the position of the first light intensity distribution with respect to the arrangement direction relative to the second light intensity distribution based on the shapes of the first light intensity distribution and the second light intensity distribution. And an intensity ratio calculation unit for obtaining a ratio of light intensity at each position in the arrangement direction in the first light intensity distribution and the second light intensity distribution in which the relative positions are matched.

  According to the present invention, the distribution of reflectance, diffraction efficiency, or transmittance in a plurality of modulation elements of a spatial light modulator can be obtained accurately and in a short time.

It is a figure which shows the structure of the modulator evaluation apparatus which concerns on 1st Embodiment. It is a figure which shows the structure of the modulator evaluation apparatus which concerns on 1st Embodiment. It is a block diagram which shows the structure of a calculating part. It is a figure which shows the flow of the process which evaluates a spatial light modulator. It is a figure which overlaps and shows the 1st light intensity distribution and the 2nd light intensity distribution. It is a figure which superimposes a corresponding partial distribution on an attention partial distribution. It is a figure which shows the relationship between an evaluation value and shift amount. It is a figure which superimposes a corresponding partial distribution on an attention partial distribution. It is a figure which overlaps and shows the 1st light intensity distribution and the 2nd light intensity distribution. It is a figure which shows the other example of a modulator evaluation apparatus. It is a figure which shows the structure of the main body of the modulator evaluation apparatus which concerns on 2nd Embodiment. It is a figure which shows a part of flow of a process which evaluates a spatial light modulator. It is a figure which shows the other example of a modulator evaluation apparatus.

  FIG. 1 and FIG. 2 are diagrams showing the configuration of the modulator evaluation device 1 according to the first embodiment of the present invention. 1 and 2, the X direction, the Y direction, and the Z direction orthogonal to each other are indicated by arrows, and FIG. 1 illustrates the modulator evaluation device 1 viewed from the (+ Y) side toward the (−Y) direction. The main body 10 is shown, and FIG. 2 shows the main body 10 viewed from the (−X) side in the (+ X) direction. The modulator evaluation device 1 is provided, for example, in a drawing device manufacturing factory, and is used to evaluate the spatial light modulator 9 before being incorporated into the drawing device.

  The modulator evaluation device 1 includes a main body 10 and a computer 50 (see FIG. 1). The computer 50 is responsible for overall control of the modulator evaluation device 1. The main body 10 includes a light source unit 2, an optical system 3, a first detection unit 41, and a second detection unit 42. The light source unit 2 is a semiconductor laser, for example, and emits outgoing light along an optical axis J1 parallel to the Z direction. Light emitted from the light source unit 2 is guided to the first detection unit 41 and the second detection unit 42 by the optical system 3.

  Specifically, the light emitted from the light source unit 2 is collimated by the collimator lens 311 to become parallel light and passes through the two cylindrical lenses 312 and 313. The two cylindrical lenses 312 and 313 both have power only in the Y direction. When viewed along the Y direction as shown in FIG. 1, the light collimated by the collimator lens 311 passes through the cylindrical lenses 312 and 313 as parallel light and enters the beam splitter 32.

  The beam splitter 32 as a deflecting unit divides incident light into two at a predetermined branching ratio (division ratio), transmits one toward the (+ Z) side, and the other toward the (+ X) side. Reflect. The light traveling from the beam splitter 32 toward the (+ Z) side is incident on the cylindrical lens 331 as parallel light. The cylindrical lens 331 has power only in the X direction, and the light is collected with respect to the X direction at a position P1 that is away from the cylindrical lens 331 by the focal length to the (+ Z) side. The spatial light modulator 9 to be evaluated is arranged at the position P1. Hereinafter, the position P1 is referred to as “measurement position P1”.

  Here, the spatial light modulator 9 will be described. The spatial light modulator 9 is, for example, a diffraction grating type and a reflection type, and is a diffraction grating capable of changing the depth of the grating. The spatial light modulator 9 is manufactured using a semiconductor device manufacturing technique. The diffraction grating type optical modulator used in the present embodiment is, for example, GLV (Grating Light Valve) (registered trademark of Silicon Light Machines (Sunnyvale, Calif.)). The spatial light modulator 9 has a plurality of grating elements arranged in a line, and each grating element (ribbon pair) emits first-order diffracted light and zero-order diffracted light (0th-order light). Transition between. With such a structure, the spatially modulated light can be emitted from the spatial light modulator 9. In the following description, one grating element is referred to as a “modulation element”. Several lattice elements adjacent to each other may be regarded as one modulation element.

  In the spatial light modulator 9 arranged at the measurement position P1, all modulation elements arranged in the Y direction are set to emit 0th-order diffracted light. Light from the spatial light modulator 9 is guided to the detection surface of the first detection unit 41 (a set of light receiving surfaces of a plurality of light receiving elements described later) by lenses 332 and 333. In practice, an image of the surface of the spatial light modulator 9 is formed on the detection surface of the first detector 41 by the lenses 332 and 333, that is, the surface of the spatial light modulator 9 and the detection of the first detector 41. The surface is disposed at an optically conjugate position. Thus, the first partial optical system 33 including the cylindrical lens 331 and the lenses 332 and 333 guides the light transmitted through the beam splitter 32 to the first detection unit 41 via the spatial light modulator 9. The lenses 332 and 333 and the first detection unit 41 are accommodated in the case C1.

  The light traveling from the beam splitter 32 toward the (+ X) side is incident on the cylindrical lens 341 as parallel light. The cylindrical lens 341 has power only in the Z direction, and the light is condensed with respect to the Z direction at a position away from the cylindrical lens 341 by the focal distance to the (+ X) side. A reference mirror 8 is disposed at this position. The light reflected by the reference mirror 8 is guided to the detection surface of the second detection unit 42 by the lenses 342 and 343. Actually, an image of the surface of the reference mirror 8 is formed on the detection surface of the second detection unit 42 by the lenses 342 and 343, that is, the surface of the reference mirror 8 and the detection surface of the second detection unit 42 are optical. Are arranged at conjugate positions. As described above, the second partial optical system 34 including the cylindrical lens 341 and the lenses 342 and 343 guides the light reflected from the beam splitter 32 to the second detection unit 42 via the reference mirror 8. The lenses 342 and 343 and the second detection unit 42 are accommodated in the case C2.

  On the other hand, when viewed along the X direction as shown in FIG. 2, the two cylindrical lenses 312 and 313 between the collimator lens 311 and the beam splitter 32 have both focal lengths (Y direction) along the optical axis J1. Are separated from each other by the sum of the focal lengths). Therefore, the outgoing light incident on the cylindrical lens 312 is emitted as parallel light from the cylindrical lens 313. In the example of FIG. 2, the focal length of the cylindrical lens 313 arranged on the (+ Z) side is larger than the focal length of the cylindrical lens 312 arranged on the (−Z) side, and the light emitted from the cylindrical lens 313 is The width in the Y direction is larger than the width of the light incident on the cylindrical lens 312. Thus, the two cylindrical lenses 312 and 313 function as an expander.

  As described above, the light emitted from the cylindrical lens 313 as parallel light is divided by the beam splitter 32, a part thereof is guided to the spatial light modulator 9 at the measurement position P 1, and the rest is directed to the reference mirror 8. It is guided. In the path from the beam splitter 32 to the spatial light modulator 9, the light is collected in the X direction without receiving a lens action in the Y direction. Therefore, an irradiation region of light long in the Y direction is formed on the surface of the spatial light modulator 9. That is, the surface of the spatial light modulator 9 is irradiated with a line beam (light having a linear cross section). An irradiation region of light that is long in the Y direction is also formed on the detection surface of the first detection unit 41 on which an image of the surface of the spatial light modulator 9 is formed.

  In the spatial light modulator 9, a plurality of modulation elements are arranged in the Y direction, and also in the first detector 41, the plurality of light receiving elements are parallel to the Y direction (hereinafter referred to as “first arrangement direction”). Arranged. Thereby, in the 1st detection part 41, the distribution in the 1st arrangement direction (Y direction) of the intensity | strength (light quantity per unit time) of the 0th-order diffracted light radiate | emitted from the some modulation element of the spatial light modulator 9 is acquirable. It is. In the preferable modulator evaluation device 1, the line beam is irradiated to all the modulation elements of the spatial light modulator 9, and the light reflected by these modulation elements is irradiated to the first detection unit 41.

  In the path from the beam splitter 32 to the reference mirror 8, the light is collected in the Z direction without receiving a lens action in the Y direction. Therefore, an irradiation region of light long in the Y direction is formed on the surface of the reference mirror 8. As will be described later, the surface of the reference mirror 8 is irradiated with a line beam having an intensity distribution (profile) having the same shape as the line beam irradiated on the surface of the spatial light modulator 9. The reference mirror 8 has as its surface a reflecting surface that is long in the Y direction (for example, longer than the width of the line beam in the Y direction). An irradiation region of light that is long in the Y direction is also formed on the detection surface of the second detection unit 42 on which an image of the surface of the reference mirror 8 is formed. In the second detection unit 42, the plurality of light receiving elements are arranged in a direction parallel to the Y direction (hereinafter referred to as “second arrangement direction”). Thereby, in the 2nd detection part 42, distribution in the 2nd arrangement direction (Y direction) of the intensity | strength of the reflected light in the reference mirror 8 is acquirable.

  In the optical system 3, the optical characteristics of the cylindrical lens 331 and the lenses 332 and 333 in the first partial optical system 33 coincide with the optical characteristics of the cylindrical lens 341 and the lenses 342 and 343 in the second partial optical system 34, respectively. Further, the relative positional relationship between the beam splitter 32, the lenses 331 to 333 of the first partial optical system 33 and the first detector 41 is such that the lenses 341 to 343 of the beam splitter 32 and the second partial optical system 34 and the second detector 42. It matches the relative positional relationship of. Thus, the configuration of the first partial optical system 33 arranged on the path from the beam splitter 32 to the first detection unit 41 is different from that of the beam splitter 32 except for the spatial light modulator 9 arranged at the measurement position P1. The configuration is the same as that of the second partial optical system 34 disposed on the path leading to the second detection unit 42. If a mirror is disposed at the measurement position P1 instead of the spatial light modulator 9, the first detection unit 41 and the second detection unit 42 obtain light intensity distributions having the same shape. That is, the first detection unit 41 and the second detection unit 42 are disposed at positions that are optically equivalent to each other.

  FIG. 3 is a block diagram illustrating a configuration of the calculation unit 5 of the modulator evaluation device 1. The computing unit 5 is realized by the computer 50. The calculation unit 5 includes an alignment unit 51 and an intensity ratio calculation unit 52. The alignment unit 51 includes an evaluation value acquisition unit 511 and an intensity distribution arrangement unit 512. Details of the functions of these configurations will be described later. In addition, these structures may be constructed | assembled by a dedicated electrical circuit, and a dedicated electrical circuit may be utilized partially.

  FIG. 4 is a diagram illustrating a process flow in which the modulator evaluation device 1 evaluates the spatial light modulator 9. In the present processing example, the reflectance distribution in the plurality of modulation elements of the spatial light modulator 9 is acquired. In the evaluation process of the spatial light modulator 9, first, the spatial light modulator 9 to be evaluated is arranged at the measurement position P1 (step S11). Subsequently, emission of emitted light from the light source unit 2 is started, and light intensity distributions in the first arrangement direction are collectively acquired by the plurality of light receiving elements of the first detection unit 41 (step S12). As described above, the light intensity distribution acquired by the first detection unit 41 is the intensity distribution of the 0th-order diffracted light emitted from the plurality of modulation elements of the spatial light modulator 9.

  At almost the same time as step S12, the light intensity distribution in the second arrangement direction is collectively acquired by the plurality of light receiving elements of the second detection unit 42 (step S13). As described above, the light intensity distribution acquired by the second detection unit 42 is the intensity distribution of the reflected light at the reference mirror 8. In the description of the modulator evaluation device 1, the light intensity distribution acquired by the first detection unit 41 is referred to as “first light intensity distribution”, and the light intensity distribution acquired by the second detection unit 42 is referred to as “second light intensity”. Called “distribution”. The first light intensity distribution and the second light intensity distribution are output to the alignment unit 51 of the calculation unit 5.

  In the alignment unit 51, the first light intensity distribution and the second light intensity distribution are overlapped while aligning the first array direction and the second array direction as the array direction. FIG. 5 is a diagram showing the first light intensity distribution and the second light intensity distribution in an overlapping manner. The vertical axis in FIG. 5 indicates the light intensity, and the horizontal axis indicates the position in the arrangement direction. In FIG. 5, in each of the first detection unit 41 and the second detection unit 42, the position of the center light receiving element in the arrangement direction is set to 0 [μm]. The same applies to other diagrams showing the light intensity distribution. The first light intensity distribution indicated by the solid line denoted by reference numeral L1 in FIG. 5 and the second light intensity distribution indicated by the broken line denoted by reference numeral L2 are approximately approximate shapes, but are slightly shifted in the arrangement direction. Yes.

  Subsequently, in the alignment unit 51, a process of aligning the positions of the first and second light intensity distributions L1 and L2 is performed. In the process of aligning the positions of the first and second light intensity distributions L1 and L2, considering that the spatial light modulator 9 and the reference mirror 8 are irradiated with a line beam having the same intensity distribution, The first and second light intensity distributions L1, L1 and L2 so that the light intensity of the first light intensity distribution L1 and the light intensity of the second light intensity distribution L2 derived from the light at the same position are the same position in the arrangement direction. L2 is arranged.

  Here, the intensity distribution of the line beam irradiated on the surface of the spatial light modulator 9 (and the surface of the reference mirror 8) has a variation of several percent to several tens percent. On the other hand, the reflectance in the spatial light modulator 9 differs depending on the position in the direction in which the modulation elements are arranged. However, since the change in reflectance is relatively gentle, the reflectance is almost constant in a narrow range in the direction. Can be considered. Therefore, when the second light intensity distribution L2 is shifted (moved) in the arrangement direction with respect to the first light intensity distribution L1, the light intensity of the first light intensity distribution L1 over a certain narrow range in the arrangement direction. The shift amount at which the ratio of the light intensity of the second light intensity distribution L2 is constant (that is, a substantially constant reflectivity is obtained) is shifted so that the positions of the first and second light intensity distributions L1 and L2 are aligned. It can be said that it is a distance. In the processing of the alignment unit 51 described below, such a shift amount (specific shift amount) is obtained.

  In the evaluation value acquisition unit 511 of the alignment unit 51, first, the portion of the first light intensity distribution L1 included in the range of a predetermined setting width in the arrangement direction (the range indicated by the arrow denoted by the symbol R1 in FIG. 5). Are extracted as the attention partial distribution (step S14). In FIG. 5, the range R1 is set wide for convenience of explanation, but actually, a width narrower than the range R1 shown in FIG. 5 is determined as the set width (the same applies to ranges R2 and R3 described later). In the present embodiment, the partial distribution of interest in each of the other ranges R2 and R3 shown in FIG. 5 is also extracted. That is, a plurality of distributions of interest are extracted from the first light intensity distribution L1.

  Subsequently, in the second light intensity distribution L2, a part having the same setting width as each target part distribution is extracted as a corresponding part distribution for the target part distribution. At this time, the position where the corresponding partial distribution is extracted is near the position of the target partial distribution. Then, the corresponding partial distribution is superimposed on the target partial distribution so that the positions of both ends of the corresponding partial distribution in the arrangement direction coincide with the positions of both ends of the target partial distribution.

FIG. 6 is a diagram showing the corresponding partial distribution superimposed on the target partial distribution. In FIG. 6, symbols Lp1 and Lp2 are assigned to the target partial distribution and the corresponding partial distribution, respectively. Subsequently, at each position i in the arrangement direction of each target partial distribution Lp1, the ratio between the light intensity I _GP (i) of the target partial distribution Lp1 and the light intensity I _MP (i) of the corresponding partial distribution Lp2 (ie, (I _GP (i) / I _MP (i)), hereinafter referred to as “light intensity ratio”). Then, for the target partial distribution Lp1, a value indicating the variation in the light intensity ratio at a plurality of positions in the arrangement direction is obtained as an evaluation value. For example, three times the standard deviation is used as a value indicating the variation (evaluation value). The value indicating the variation may be the standard deviation itself, the variance, or the difference (range) between the maximum value and the minimum value.

  Here, when the corresponding partial distribution Lp2 has a shape following the target partial distribution Lp1, the light intensity ratios at a plurality of positions are approximately constant (see FIG. 8 described later). On the other hand, when the shape of the corresponding partial distribution Lp2 is significantly different from the shape of the target partial distribution Lp1, the light intensity ratios at a plurality of positions vary greatly. Therefore, it can be said that the evaluation value indicating the variation in the light intensity ratio is an index indicating the difference between the shape of the target partial distribution Lp1 and the shape of the corresponding partial distribution Lp2.

  Subsequently, in the second light intensity distribution L2, a position shifted by a minute distance in the arrangement direction from the current position of the corresponding partial distribution Lp2 is extracted as a new corresponding partial distribution Lp2. Then, an evaluation value is obtained using the new corresponding partial distribution Lp2 by the same processing as described above. In the evaluation value acquisition unit 511, extraction of a new corresponding partial distribution Lp2 and calculation of an evaluation value are repeated a predetermined number of times. In this way, the evaluation value is acquired while shifting the position of the set width portion extracted as the corresponding partial distribution Lp2 in the second light intensity distribution L2 in the arrangement direction (step S15). In other words, with respect to the arrangement direction, an evaluation value is obtained for a plurality of shift amounts, with the distance between the central position of the target partial distribution Lp1 and the central position of the corresponding partial distribution Lp2 in the second light intensity distribution L2 as a shift amount. To be acquired. Acquisition of evaluation values for a plurality of shift amounts is performed for each of the plurality of target partial distributions Lp1. Note that the position extracted as the corresponding partial distribution Lp2 is shifted to both sides of the arrangement direction (both in the (+ Y) direction and the (−Y) direction).

  The evaluation value acquisition unit 511 may extract a target partial distribution in the second light intensity distribution L2 and extract a corresponding partial distribution in the first light intensity distribution L1. That is, in step S14, a portion having a predetermined width in the arrangement direction in one of the first light intensity distribution L1 and the second light intensity distribution L2 is extracted as the attention partial distribution, and in step S15, the other light intensity distribution is extracted. The evaluation value is acquired while shifting the position of the portion of the predetermined width extracted as the corresponding partial distribution in the arrangement direction.

  FIG. 7 is a diagram illustrating a relationship between an evaluation value acquired for one target partial distribution Lp1 and a shift amount. In the intensity distribution arrangement unit 512, the shift amount that is the smallest evaluation value among the plurality of evaluation values acquired for the target partial distribution Lp1 is specified as the specific shift amount. In the example of FIG. 7, as indicated by the broken-line arrow denoted by reference numeral A1, when the shift amount is (+200) μm, the evaluation value is minimized, so (+200) μm is specified as the specific shift amount. The

  FIG. 8 is a diagram showing the corresponding partial distribution Lp2 when the minimum evaluation value is acquired, superimposed on the target partial distribution Lp1. As described above, the evaluation value is a value indicating variation in the light intensity ratio at a plurality of positions in the arrangement direction. As shown in FIG. 8, the ratio between the light intensity of the target partial distribution Lp1 and the light intensity of the corresponding partial distribution Lp2 is substantially constant, and the corresponding partial distribution Lp2 is The shape follows the target partial distribution Lp1. By acquiring the specific shift amount, the position of the corresponding partial distribution Lp2 when the shape of the target partial distribution Lp1 and the shape of the corresponding partial distribution Lp2 are most approximate is obtained.

  Actually, a specific shift amount is acquired for each of the plurality of target partial distributions Lp1, and a representative value such as an average value of the plurality of specific shift amounts is obtained. The representative value may be a median value or the like. Then, the second light intensity distribution L2 shown in FIG. 5 is moved in the arrangement direction by a representative value of the specific shift amount with respect to the first light intensity distribution L1. As a result, as shown in FIG. 9, the position of the first light intensity distribution L1 with respect to the arrangement direction is relatively matched to the second light intensity distribution L2 (step S16). In step S16, the first light intensity distribution L1 may be moved in the arrangement direction with respect to the second light intensity distribution L2.

The intensity ratio calculation unit 52 calculates the light intensity of the first light intensity distribution L1 at each position i in the arrangement direction as I _G (i) in the first and second light intensity distributions L1 and L2 whose relative positions are matched. R _G (i) is obtained from Equation 1, where I _M (i) is the light intensity of the second light intensity distribution L2, R _{M is} the reflectance of the reference mirror 8, and α is the branching ratio of the beam splitter 32. Incidentally, the intensity of light P _G to be irradiated on the spatial light modulator _9, the intensity of light applied to the reference mirror 8 as P _M, the α branching ratio of the beam splitter 32 at (P M _{/ P G)} expressed.

(Equation 1)
R _G (i) = (I _G (i) / I _M (i)) · R _M · α

R _G (i) in Equation 1 represents the reflectance of the modulation element of the spatial light modulator 9 conjugate with the position i on the first detection unit 41. In this way, in the first light intensity distribution L1 and the second light intensity distribution L2 in which the relative positions are matched, the ratio of light intensity at each position i in the arrangement direction (I _G (i) / I _M (i) ) Is obtained, the reflectance of the modulation element of the spatial light modulator 9 corresponding to the position i is obtained (step S17). Thereby, the reflectance distribution in the plurality of modulation elements of the spatial light modulator 9 is acquired.

  Actually, steps S11 to S17 are repeated for the plurality of spatial light modulators 9. At this time, every time the evaluation target spatial light modulator 9 is replaced, the overall inclination of the spatial light modulator 9 disposed at the measurement position P1 (a minute inclination with respect to the Y direction in the direction in which the modulation elements are arranged) or the like changes. . Therefore, the modulator evaluation apparatus 1 requires a process for aligning the positions of the first and second light intensity distributions L1 and L2 when each spatial light modulator 9 is evaluated.

  Here, the stage in which the spatial light modulator and the reference mirror are arranged side by side is moved at a constant speed with respect to the irradiation position of the light emitted from the light source unit (the position where the dotted irradiation area is formed). Thus, a device of a comparative example in which the irradiation position is sequentially passed through the reference mirror and the plurality of modulation elements of the spatial light modulator is assumed. In the apparatus of the comparative example, the reflectance of the plurality of modulation elements is obtained by receiving the reflected light from the irradiation position by a detection unit having a single light receiving element. However, since the apparatus of the comparative example accompanies movement of the stage at a constant speed, it is difficult to obtain the reflectance distribution in the spatial light modulator in a short time.

  On the other hand, in the modulator evaluation device 1, the first detection unit 41 in which a plurality of light receiving elements are arranged receives light that has passed through the plurality of modulation elements of the spatial light modulator 9, and the first light intensity distribution L1 is collectively displayed. And get it. In addition, light that does not pass through the spatial light modulator 9 is received by the second detection unit 42 that is disposed at a position that is optically equivalent to the first detection unit 41 and in which a plurality of light receiving elements are arranged. Distribution L2 is acquired collectively. The computing unit 5 superimposes the first light intensity distribution L1 and the second light intensity distribution L2, and based on the shapes of the first light intensity distribution L1 and the second light intensity distribution L2, the first light intensity distribution related to the arrangement direction. The position of L1 is relatively aligned with the second light intensity distribution L2. Then, in the first light intensity distribution L1 and the second light intensity distribution L2 in which the relative positions are matched, the ratio of the light intensity at each position in the arrangement direction is obtained. Thereby, the distribution of the reflectance in the plurality of modulation elements of the spatial light modulator 9 can be obtained with high accuracy while taking the intensity distribution of the light emitted from the light source unit 2 into consideration. Further, since there is no movement of the stage unlike the apparatus of the comparative example, the reflectance distribution can be obtained in a short time.

  Further, in the alignment of the first light intensity distribution L1 and the second light intensity distribution L2, the part of interest distribution Lp1 is extracted in one light intensity distribution, and the part extracted as the corresponding part distribution Lp2 in the other light intensity distribution An evaluation value indicating the difference between the shape of the target partial distribution Lp1 and the shape of the corresponding partial distribution Lp2 is acquired while shifting the position of. Based on the evaluation value, a specific shift amount that is a distance between the position of the corresponding partial distribution Lp2 and the position of the target partial distribution Lp1 when the shapes of the partial distributions Lp1 and Lp2 are most approximated is obtained. Using the specific shift amount, the position of the first light intensity distribution L1 with respect to the arrangement direction is relatively aligned with the second light intensity distribution L2. As a result, in consideration of the overall shape of the first light intensity distribution L1 and the second light intensity distribution L2, the amount of calculation can be reduced compared to the case where both are aligned, and the reflectance distribution can be further increased. It can be obtained in a short time. The evaluation value may be a value indicating a variation in the difference between the two light intensities other than a value indicating a variation in the ratio between the light intensity of the target partial distribution Lp1 and the light intensity of the corresponding partial distribution Lp2.

  In the preferred modulator evaluation apparatus 1, a plurality of target partial distributions Lp1 are extracted, and the positions of the first light intensity distributions L1 in the arrangement direction using a plurality of specific shift amounts obtained for the plurality of target partial distributions Lp1. Is relatively adjusted with respect to the second light intensity distribution L2. Thereby, it is possible to perform the alignment of the first and second light intensity distributions L1 and L2 with higher accuracy while reducing the amount of calculation to some extent and suppressing the influence of calculation errors and the like. The first and second light intensity distributions L1 and L2 are aligned in consideration of the overall shape of the first and second light intensity distributions L1 and L2, depending on the processing capability of the calculation unit 5 and the like. Also good.

  Here, in the optical system 3, a state in which light that has passed through the spatial light modulator 9 out of the emitted light emitted from the light source unit 2 is incident on the first detection unit 41 is referred to as a “first state”, and the space A state in which the light before entering the light modulator 9 is incident on the second detection unit 42 without passing through the spatial light modulator 9 is referred to as a “second state”. In this case, in the modulator evaluation device 1 of FIG. 1, it can be said that the first state and the second state are realized at the same time by the beam splitter 32 which is a deflection unit. Thereby, step S12 which acquires the 1st light intensity distribution L1 by the 1st detection part 41 in the 1st state, and step S13 which acquires the 2nd light intensity distribution L2 by the 2nd detection part 42 in the 2nd state, Can be performed simultaneously. As a result, it is possible to obtain the reflectance distribution in the plurality of modulation elements of the spatial light modulator 9 in a shorter time. Moreover, even if the intensity distribution of the emitted light from the light source unit 2 varies with time, the reflectance distribution can be obtained with high accuracy.

  Next, the modulator evaluation device 1 that realizes the first state and the second state separately will be described. FIG. 10 is a diagram illustrating another example of the modulator evaluation device 1 and shows only the main body 10. The modulator evaluation apparatus 1 in FIG. 10 is different from the modulator evaluation apparatus 1 in FIG. 1 in that a deflecting unit 32 a is provided instead of the beam splitter 32. Other configurations are the same as those in FIG. 1, and the same reference numerals are given to the same configurations.

  The deflecting unit 32a includes a mirror 321 and a mirror advance / retreat mechanism 322 that moves the mirror 321 in the X direction. The mirror advance / retreat mechanism 322 includes a first position (the position of the mirror 321 indicated by a solid line in FIG. 10) that separates the mirror 321 from the optical axis J1, and a second position on the optical axis J1 (in FIG. 10). And the position of the mirror 321 indicated by a two-dot chain line). The deflecting unit 32a arranges the mirror 321 at the first position, so that all of the emitted light emitted from the light source unit 2 enters the first detection unit 41 via the spatial light modulator 9. It becomes. The deflecting unit 32a arranges the mirror 321 at the second position, so that all the outgoing light emitted from the light source unit 2 is reflected (deflected) by the mirror 321 before entering the spatial light modulator 9, A second state of entering the second detector 42 via the reference mirror 8 is obtained.

  In the evaluation process of the spatial light modulator 9 by the modulator evaluation device 1 of FIG. 10, when the emission of the emitted light from the light source unit 2 is started, the first state is obtained in the first state where the mirror 321 is separated from the optical axis J1. The first light intensity distribution is acquired by the detector 41 (FIG. 4: step S12). Subsequently, the deflecting unit 32a places the mirror 321 on the optical axis J1, and the second light intensity distribution is acquired by the second detecting unit 42 in the second state (step S13). The processing after the acquisition of the first light intensity distribution and the second light intensity distribution is the same as that of the modulator evaluation device 1 of FIG.

  The movement (advance and retreat) of the mirror 321 in the deflecting unit 32a can be completed in a shorter time than the movement of the stage at a constant speed in the apparatus of the comparative example. Therefore, it can be said that the modulator evaluation apparatus 1 having the deflecting unit 32a can also obtain the reflectance distribution in the plurality of modulation elements of the spatial light modulator 9 in a short time. In the modulator evaluation device 1 of FIG. 10, the intensity of light incident on the first and second detectors 41 and 42 can be increased, and the influence of noise can be suppressed. On the other hand, from the viewpoint of obtaining the reflectance distribution in a shorter time and more stably without providing a movable part such as the mirror advance / retreat mechanism 322, a beam splitter like the modulator evaluation apparatus 1 in FIG. 32 is preferably provided as a deflection unit.

  FIG. 11 is a diagram showing a configuration of the main body 10 of the modulator evaluation device 1a according to the second embodiment of the present invention. In the modulator evaluation device 1a of FIG. 11, the beam splitter 32, the second partial optical system 34, and the second detection unit 42 in the modulator evaluation device 1 of FIG. 1 are omitted, and a replacement unit 81 is added to the measurement position P1. . Other configurations are the same as those in FIG. 1, and the same reference numerals are given to the same configurations.

  The replacement unit 81 includes a support base 811 and a rotation mechanism 812. The support base 811 supports the reference mirror 8 that is long in the Y direction and the spatial light modulator 9 in which a plurality of modulation elements are arranged in the Y direction. That is, the reference mirror 8 and the spatial light modulator 9 are supported in an upright state on the support base 811. The rotation mechanism 812 selectively rotates the surface of the spatial light modulator 9 and the surface of the reference mirror 8 to the measurement position P1 by rotating the support base 811 around the rotation axis K1 parallel to the Y direction. Deploy.

  FIG. 12 is a diagram showing a part of the process flow in which the modulator evaluation device 1a evaluates the spatial light modulator 9, and shows the process performed between step S12 and step S13 in FIG. In the evaluation process of the spatial light modulator 9, first, the spatial light modulator 9 to be evaluated is arranged at the measurement position P1 by the rotation mechanism 812 (FIG. 4: step S11). Note that the spatial light modulator 9 is attached to the support base 811 in advance. In a state where the spatial light modulator 9 is arranged at the measurement position P1, emission of the emitted light from the light source unit 2 is started, and the light intensity distribution in the first arrangement direction is collectively collected by the plurality of light receiving elements of the first detection unit 41. (Step S12). At this time, the light intensity distribution acquired by the first detection unit 41 is the intensity distribution of the 0th-order diffracted light emitted from the plurality of modulation elements of the spatial light modulator 9.

  Subsequently, when the rotation mechanism 812 rotates the support base 811, the reference mirror 8 that is a reflection portion is arranged at the measurement position P <b> 1 (FIG. 12: step S <b> 12 a). Then, in a state in which the reference mirror 8 is arranged at the measurement position P1, the light intensity distribution in the first arrangement direction is collectively acquired by the plurality of light receiving elements of the first detection unit 41 (FIG. 4: step S13). At this time, the light intensity distribution acquired by the first detection unit 41 is the intensity distribution of the reflected light in the reference mirror 8. In the modulator evaluation device 1a provided with only one detection unit (first detection unit 41), the intensity distribution of the light that has passed through the spatial light modulator 9 and is acquired by the first detection unit 41 is expressed as “first light intensity”. The intensity distribution of light that has passed through the reference mirror 8 is referred to as “second light intensity distribution”. The processing after the acquisition of the first light intensity distribution and the second light intensity distribution is the same as that of the modulator evaluation device 1 of FIG.

  The rotation of the support base 811 in the replacement unit 81 (replacement of the spatial light modulator 9 and the reference mirror 8 at the measurement position P1) is shorter than the movement of the stage at a constant speed in the above-described comparative apparatus. It can be completed in time. Therefore, it can be said that the modulator evaluation apparatus 1a of FIG. 11 can also obtain the reflectance distribution in the plurality of modulation elements of the spatial light modulator 9 in a short time. Further, in the first light intensity distribution and the second light intensity distribution in which the relative positions are matched, the ratio of the light intensity at each position in the arrangement direction is obtained, so that the reflectance distribution of the spatial light modulator 9 can be reduced. Thus, it can be accurately obtained in consideration of the intensity distribution of the emitted light from the light source unit 2.

  Also in the modulator evaluation device 1a of FIG. 11, the above evaluation process is repeated for a plurality of spatial light modulators 9. At this time, every time the spatial light modulator 9 to be evaluated is replaced, the overall inclination of the spatial light modulator 9 attached to the support base 811 (a minute inclination with respect to the Y direction in the direction in which the modulation elements are arranged) or the like changes. Therefore, as with the modulator evaluation device 1, the first light intensity distribution and the second light intensity distribution need to be aligned when each spatial light modulator 9 is evaluated. In other words, by performing alignment between the first light intensity distribution and the second light intensity distribution, the reflectance distribution of the spatial light modulator 9 can be obtained stably and accurately.

  Various modifications can be made in the modulator evaluation devices 1 and 1a.

  In the modulator evaluation apparatus 1 of FIGS. 1 and 10, the configuration of the first partial optical system 33 is the same as the configuration of the second partial optical system 34 except for the spatial light modulator 9 disposed at the measurement position P1. Thus, the second detector 42 can be easily arranged at a position optically equivalent to the first detector 41. Depending on the design of the modulator evaluation device 1, the first and second portions can be realized. The configuration of the optical system may be different. For example, in the second partial optical system 34 of FIG. 1, the lenses 342 and 343 and the reference mirror 8 may be omitted, and the second detection unit 42 may be disposed at the position of the reference mirror 8. Also in this case, it can be said that the second detection unit 42 is disposed at a position optically equivalent to the first detection unit 41. Further, the magnification of the image of the spatial light modulator 9 formed on the detection surface of the first detection unit 41 may be different from the magnification of the image of the reference mirror 8 formed on the detection surface of the second detection unit 42. . In this case, the calculation unit 5 adds processing for changing the size of the first light intensity distribution or the second light intensity distribution according to the difference in magnification between the two.

  In the modulator evaluation devices 1 and 1a according to the first and second embodiments, the direction in which the plurality of modulation elements are arranged in the image of the spatial light modulator 9 formed on the detection surface of the first detection unit 41 is the first. If the detection unit 41 substantially coincides with the first arrangement direction in which the plurality of light receiving elements are arranged, the direction in which the modulation elements are arranged in the spatial light modulator 9 arranged at the measurement position P1 and the first arrangement direction are It may be different. As a configuration for making the two directions different, for example, a mirror or the like that bends the optical axis in the X direction may be provided between the measurement position P1 and the first detection unit 41 (the first arrangement direction is different from the second arrangement direction). The same applies to

  In the modulator evaluation device 1 according to the first embodiment, when a mirror is disposed at the measurement position P1 instead of the spatial light modulator 9, the first detector 41 and the second detector 42 have the same shape. If the intensity distribution is acquired (that is, the arrangement direction of the light receiving elements corresponds to each other), the first arrangement direction is different from the second arrangement direction in which the plurality of light receiving elements are arranged in the second detection unit 42. May be.

  As described above, in the modulator evaluation device 1 in which the first and second detection units 41 and 42 are provided, the spatial light modulator 9 disposed in the first arrangement direction, the second arrangement direction, and the measurement position P1. The direction in which the modulation elements are arranged may correspond to each other. Further, in the modulator evaluation device 1a in which only one first detection unit 41 is provided, the first arrangement direction and the direction in which the modulation elements of the spatial light modulator 9 arranged at the measurement position P1 correspond to each other. Good.

  All the modulation elements in the diffraction grating type spatial light modulator 9 are in a state of emitting the first-order diffracted light. In the first detection unit 41, the intensity distribution of the first-order diffracted light emitted from the plurality of modulation elements is It may be acquired as a single light intensity distribution. In this case, the intensity ratio calculation unit 52 obtains the distribution of diffraction efficiency in the plurality of modulation elements based on the ratio of the light intensity in the first light intensity distribution and the second light intensity distribution.

  Further, in the modulator evaluation devices 1 and 1a, evaluation of a transmissive spatial light modulator (for example, a liquid crystal light modulator) may be performed. In this case, for example, as illustrated in FIG. 13, the cylindrical lens 331 and the lenses 332 and 333 and the first detection unit 41 in the first partial optical system 33 are arranged in a line along the Z direction. The transmissive spatial light modulator 9 a is disposed between the cylindrical lens 331 and the lens 332. In the transmissive spatial light modulator 9a, a plurality of modulation elements are arranged in the Y direction. Further, the cylindrical lens 341 and the lenses 342 and 343 and the second detection unit 42 in the second partial optical system 34 are arranged in a line along the X direction. The reference mirror 8 is not provided in the second partial optical system 34. In the modulator evaluation device 1 of FIG. 13, the transmitted light intensity distribution in the plurality of modulation elements of the spatial light modulator 9 a is acquired as the first light intensity distribution by the plurality of light receiving elements of the first detection unit 41. The second light intensity distribution is acquired by the second detection unit 42. Then, in the first light intensity distribution and the second light intensity distribution in which the relative positions are matched, the ratio of the light intensity at each position in the arrangement direction is obtained, thereby obtaining the transmittance distribution in the plurality of modulation elements. Is done.

  Similarly, in the modulator evaluation device 1a of FIG. 11, the cylindrical lens 331 and the lenses 332 and 333 and the first detection unit 41 in the first partial optical system 33 and the first detection unit 41 are arranged in a line along the Z direction, and the support base 811 is arranged. The transmittance distribution of the transmissive spatial light modulator provided above may be acquired. In this case, in step S12a of FIG. 12, the spatial light modulator between the cylindrical lens 331 and the lens 332 is removed. In step S13 of FIG. 4, the intensity distribution of light received by the plurality of light receiving elements of the first detection unit 41 in a state where the spatial light modulator is removed is acquired as the second light intensity distribution.

  As described above, the modulator evaluation devices 1 and 1a can be used for evaluation of the reflective spatial light modulator 9 and the equivalent spatial light modulator 9a, and a plurality of modulations of the spatial light modulators 9 and 9a can be used. It is possible to obtain the reflectance, diffraction efficiency, or transmittance distribution in the element accurately and in a short time.

  Also in the modulator evaluation apparatus 1 of FIGS. 1 and 10 that measures the reflective spatial light modulator 9, the reference mirror 8 may be omitted as in the second partial optical system 34 of FIG. However, from the viewpoint of matching the relative positional relationship of the optical elements in the first partial optical system 33 with the relative positional relationship of the optical elements in the second partial optical system 34, the reference mirror 8 is preferably provided. Further, the size of the main body 10 in the X direction can be reduced by providing the reference mirror 8.

  In the embodiment described above, the one-dimensional spatial light modulators 9 and 9a in which a plurality of modulation elements are arranged in only one direction are targeted for evaluation. However, in the above technique, the plurality of modulation elements are arranged in two directions. It may be extended to the evaluation of an arrayed two-dimensional spatial light modulator. For example, in a two-dimensional spatial light modulator, when a plurality of modulation elements are arranged in two directions orthogonal to each other, the surface of the spatial light modulator spreads in the two directions by the light source unit 2 and the optical system 3. A light irradiation region is formed. In the first detection unit 41, a plurality of light receiving elements are arranged in two directions orthogonal to each other (the same applies to the second detection unit 42), and an image of the surface of the spatial light modulator is formed on the detection surface of the first detection unit 41. It is formed. Two-dimensional first light intensity distribution acquired by the first detector 41 and two-dimensional second light intensity acquired by the second detector 42 (or the first detector 41 in the modulator evaluation device 1a). In the distribution, the positions in the directions are aligned based on the shape of the intensity distribution in the directions corresponding to each other. The same applies to the direction orthogonal to the direction. Then, in the first and second light intensity distributions in which the relative positions are matched, the ratio of the light intensity at each position is obtained. As a result, the reflectance, diffraction efficiency, or transmittance distribution in the plurality of modulation elements of the two-dimensional spatial light modulator can be obtained accurately and in a short time.

  The modulator evaluation devices 1 and 1a for evaluating the spatial light modulators 9 and 9a may be provided in the manufacturing factory of the spatial light modulators 9 and 9a and used for evaluation of the spatial light modulators 9 and 9a after manufacture. . Further, some or all of the modulator evaluation devices 1 and 1a may be incorporated in the drawing device and used for evaluation of the spatial light modulators 9 and 9a attached to the drawing device.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1,1a Modulator evaluation apparatus 2 Light source part 3 Optical system 5 Calculation part 8 Reference mirror 9, 9a Spatial light modulator 32 Beam splitter 32a Deflection part 33 1st partial optical system 34 2nd partial optical system 41 1st detection part 42 2nd detection part 51 Positioning part 52 Intensity ratio calculation part 511 Evaluation value acquisition part 512 Intensity distribution arrangement part L1 1st light intensity distribution L2 2nd light intensity distribution Lp1 attention partial distribution Lp2 corresponding partial distribution P1 measurement position S11-S17, Step S12a

Claims (12)

A modulator evaluation method for evaluating a spatial light modulator,
In the optical system that guides the emitted light emitted from the light source unit to the first detection unit via the spatial light modulator arranged at a predetermined position, the light that has passed through the spatial light modulator among the emitted light The first state to be incident on the first detection unit and the light before being incident on the spatial light modulator are arranged at a position optically equivalent to the first detection unit without passing through the spatial light modulator. A deflecting unit that realizes the second state incident on the second detecting unit simultaneously or separately is provided,
A first arrangement direction in which a plurality of light receiving elements are arranged in the first detection unit, a second arrangement direction in which a plurality of light receiving elements are arranged in the second detection unit, and a plurality in the spatial light modulator arranged at the predetermined position. The direction in which the modulation elements are aligned corresponds to each other,
The modulator evaluation method comprises:
a) disposing a spatial light modulator to be evaluated at the predetermined position;
b) obtaining a first light intensity distribution in the first arrangement direction by the first detector in the first state;
c) obtaining a second light intensity distribution in the second arrangement direction by the second detector in the second state;
d) Overlapping the first light intensity distribution and the second light intensity distribution while aligning the first arrangement direction and the second arrangement direction as the arrangement direction, and the first light intensity distribution and the second light Matching the position of the first light intensity distribution with respect to the arrangement direction relative to the second light intensity distribution based on the shape of the intensity distribution;
e) obtaining a ratio of light intensity at each position in the arrangement direction in the first light intensity distribution and the second light intensity distribution in which the relative positions are matched;
A modulator evaluation method comprising: A modulator evaluation method according to claim 1, comprising:
Step d)
d1) extracting a portion having a predetermined width in the arrangement direction in one light intensity distribution of the first light intensity distribution and the second light intensity distribution as an attention partial distribution;
d2) An evaluation value indicating the difference between the shape of the target partial distribution and the shape of the corresponding partial distribution while shifting the position of the predetermined width portion extracted as the corresponding partial distribution in the other light intensity distribution in the arrangement direction. A process of obtaining
d3) obtaining a position in the arrangement direction of the corresponding partial distribution when the shape of the target partial distribution and the shape of the corresponding partial distribution are most approximated based on the evaluation value, and the position of the corresponding partial distribution Aligning the position of the first light intensity distribution relative to the arrangement direction relative to the second light intensity distribution using a specific shift amount that is a distance between the position of the target partial distribution;
A modulator evaluation method comprising: A modulator evaluation method according to claim 2, comprising:
In the step d1), a plurality of partial distributions of interest are extracted,
Step d2) is performed for each of the plurality of attention partial distributions,
In the step d3), the position of the first light intensity distribution with respect to the arrangement direction is relative to the second light intensity distribution using a plurality of specific shift amounts obtained for the plurality of target partial distributions. Modulator evaluation method characterized by being adapted to. A modulator evaluation method according to any one of claims 1 to 3,
In the optical system, the configuration of the first partial optical system arranged on the path from the deflection unit to the first detection unit is different from the deflection unit except for the spatial light modulator arranged at the predetermined position. A modulator evaluation method characterized by having the same configuration as that of a second partial optical system arranged in a path leading to the second detection unit. A modulator evaluation method according to any one of claims 1 to 4,
The deflection unit is a beam splitter;
The deflecting unit realizes the first state and the second state at the same time,
A modulator evaluation method, wherein the steps b) and c) are performed simultaneously. A modulator evaluation method for evaluating a spatial light modulator,
An optical system that guides the emitted light emitted from the light source unit to the detection unit via a spatial light modulator disposed at a predetermined position is provided.
The arrangement direction in which the plurality of light receiving elements are arranged in the detection unit and the direction in which the plurality of modulation elements are arranged in the spatial light modulator arranged at the predetermined position correspond to each other,
The modulator evaluation method comprises:
a) disposing a spatial light modulator to be evaluated at the predetermined position;
b) obtaining a first light intensity distribution in the arrangement direction by the detection unit;
c) disposing a reflector at the predetermined position or removing the spatial light modulator;
d) obtaining a second light intensity distribution in the arrangement direction by the detection unit;
e) Overlapping the first light intensity distribution and the second light intensity distribution and, based on the shapes of the first light intensity distribution and the second light intensity distribution, the first light intensity distribution in the arrangement direction. Aligning the position relative to the second light intensity distribution;
f) obtaining a ratio of light intensity at each position in the arrangement direction in the first light intensity distribution and the second light intensity distribution in which the relative positions are matched;
A modulator evaluation method comprising: A modulator evaluation device for evaluating a spatial light modulator,
A light source for emitting the emitted light;
A first detector in which a plurality of light receiving elements are arranged in the first arrangement direction;
A second detector in which a plurality of light receiving elements are arranged in the second arrangement direction;
Of the emitted light, a first state in which light that has passed through a spatial light modulator arranged at a predetermined position is incident on the first detection unit, and light before being incident on the spatial light modulator is the spatial light. A deflecting unit that realizes the second state of being incident on the second detection unit disposed at an optically equivalent position to the first detection unit without passing through a modulator, simultaneously or separately. Optical system,
An arithmetic unit;
With
The first arrangement direction, the second arrangement direction, and the direction in which a plurality of modulation elements are arranged in the spatial light modulator arranged at the predetermined position correspond to each other,
In the first state, a first light intensity distribution in the first arrangement direction is acquired by the first detection unit,
In the second state, the second light intensity distribution in the second arrangement direction is acquired by the second detection unit,
The computing unit is
While aligning the first arrangement direction and the second arrangement direction as the arrangement direction, the first light intensity distribution and the second light intensity distribution are overlapped, and the first light intensity distribution and the second light intensity distribution are overlapped. An alignment unit that aligns the position of the first light intensity distribution with respect to the arrangement direction relative to the second light intensity distribution based on the shape of
In the first light intensity distribution and the second light intensity distribution in which the relative positions are matched, an intensity ratio calculation unit for obtaining a ratio of light intensity at each position in the arrangement direction;
A modulator evaluation device comprising: The modulator evaluation device according to claim 7,
The alignment portion is
The predetermined width portion of the first light intensity distribution and the second light intensity distribution having a predetermined width in the arrangement direction is extracted as a target partial distribution and the other light intensity distribution is extracted as a corresponding partial distribution. An evaluation value acquisition unit that acquires an evaluation value indicating a difference between the shape of the target partial distribution and the shape of the corresponding partial distribution while shifting the position of the width portion in the arrangement direction;
Based on the evaluation value, the position of the corresponding partial distribution in the arrangement direction when the shape of the target partial distribution and the shape of the corresponding partial distribution are most approximated is obtained, and the position of the corresponding partial distribution and the target An intensity distribution placement unit that aligns the position of the first light intensity distribution with respect to the arrangement direction relative to the second light intensity distribution using a specific shift amount that is a distance between the positions of the partial distributions;
A modulator evaluation device comprising: The modulator evaluation device according to claim 8, comprising:
The evaluation value acquisition unit extracts a plurality of attention partial distributions, performs a process related to acquisition of the evaluation value for each of the plurality of attention partial distributions,
The intensity distribution arrangement unit uses a plurality of specific shift amounts obtained for the plurality of target partial distributions to position the first light intensity distribution relative to the arrangement direction relative to the second light intensity distribution. Modulator evaluation device characterized by matching. The modulator evaluation device according to any one of claims 7 to 9,
In the optical system, the configuration of the first partial optical system arranged on the path from the deflection unit to the first detection unit is different from the deflection unit except for the spatial light modulator arranged at the predetermined position. A modulator evaluation device having the same configuration as that of the second partial optical system arranged in a path leading to the second detection unit. The modulator evaluation device according to any one of claims 7 to 10, comprising:
The deflection unit is a beam splitter;
The deflecting unit realizes the first state and the second state at the same time,
The modulator evaluation device characterized in that the acquisition of the first light intensity distribution and the acquisition of the second light intensity distribution are performed simultaneously. A modulator evaluation device for evaluating a spatial light modulator,
A light source for emitting the emitted light;
A detection unit in which a plurality of light receiving elements are arranged in the arrangement direction;
An optical system for guiding the emitted light to the detection unit via a spatial light modulator disposed at a predetermined position;
An arithmetic unit;
With
The arrangement direction and the direction in which a plurality of modulation elements are arranged in the spatial light modulator arranged at the predetermined position correspond to each other,
The first light intensity distribution in the array direction is acquired by the detection unit in a state where the spatial light modulator to be evaluated is arranged at the predetermined position,
A second light intensity distribution in the arrangement direction is acquired by the detection unit in a state where the reflection unit is disposed at the predetermined position or the spatial light modulator is removed,
The computing unit is
The first light intensity distribution and the second light intensity distribution are overlapped, and the position of the first light intensity distribution with respect to the arrangement direction is determined based on the shapes of the first light intensity distribution and the second light intensity distribution. An alignment unit that adjusts relative to the second light intensity distribution;
In the first light intensity distribution and the second light intensity distribution in which the relative positions are matched, an intensity ratio calculation unit for obtaining a ratio of light intensity at each position in the arrangement direction;
A modulator evaluation device comprising:

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