Spatial light modulator

Abstract

A spatial light modulator according to the present disclosure comprises: a plurality of pixels having a light modulation layer that modulates the phase of incident light; and a measurement element that measures the amount of light phase modulation made by the light modulation layer.

Description

Spatial Light Modulator

[0001] The present disclosure relates to a phase modulation type spatial light modulator.

[0002] In spatial light modulators, there is a technique for recognizing degradation of liquid crystal by providing a light receiving element (see Patent Document 1).

[0003] Japanese Unexamined Patent Publication No. 2013-78999

[0004] The technique described in Patent Document 1 cannot measure the phase of light, making it difficult to perform high-precision phase modulation.

[0005] For this reason, it is desirable to provide a spatial light modulator capable of performing high-precision phase modulation.

[0006] A spatial light modulator according to an embodiment of the present disclosure includes a plurality of pixels each having a light modulation layer that modulates the phase of incident light, and a measurement element that measures the amount of phase modulation of light by the light modulation layer.

[0007] In the spatial light modulator according to an embodiment of the present disclosure, the amount of phase modulation of light by the light modulation layer is measured by the measurement element.

[0008] Figure 1 is an explanatory diagram showing an overview of the dielectric anisotropy of liquid crystal. Figure 2 is an explanatory diagram showing an overview of the refractive index anisotropy of liquid crystal. Figure 3 is a configuration diagram showing an overview of a phase-modulated spatial light modulator. Figure 4 is a schematic block diagram showing a first configuration example of a spatial light modulator according to one embodiment. Figure 5 is a schematic block diagram showing a second configuration example of a spatial light modulator according to one embodiment. Figure 6 is a schematic cross-sectional view showing an example of the pixel structure of a spatial light modulator according to one embodiment. Figure 7 is a schematic cross-sectional view showing a self-interference type configuration example 1 as an example of the configuration of a phase modulation amount measuring element. Figure 8 is an explanatory diagram showing an example of the relationship between the measured value of the phase modulation amount measuring element and the phase modulation amount by pixel B. Figure 9 is a schematic top view showing a first example of the size and arrangement position of the phase modulation amount measuring element in the configuration example of Figure 7. Figure 10 is a schematic top view showing a second example of the size and arrangement position of the phase modulation amount measuring element in the configuration example of Figure 7. Figure 11 is a schematic top view showing a third example of the size and placement of the phase modulation amount measuring element in the configuration example of Figure 7. Figure 12 is a schematic cross-sectional view showing an example of the size and placement of the phase modulation amount measuring element and pixel electrode in the configuration example of Figure 7. Figure 13 is a schematic cross-sectional view showing a self-interference type configuration example 2 as an example of the configuration of the phase modulation amount measuring element. Figure 14 is a schematic cross-sectional view showing a modified version of the self-interference type configuration example 2 of Figure 13. Figure 15 is a schematic cross-sectional view showing a self-interference type configuration example 3 as an example of the configuration of the phase modulation amount measuring element. Figure 16 is a schematic cross-sectional view showing an example of the size and placement of the aperture of the pixel electrode in the configuration example of Figure 15. Figure 17 is a schematic cross-sectional view showing a self-interference type configuration example 4 as an example of the configuration of the phase modulation amount measuring element. Figure 18 is a cross-sectional view showing an example of the wavefront state of the incident light L1 to the spatial light modulator of Figure 17. Figure 19 is a schematic cross-sectional view showing a self-interference type configuration example 5 as an example of the configuration of the phase modulation amount measuring element. Figure 20 is a schematic cross-sectional view showing an example of a self-interference configuration 6 as an example of the configuration of a phase modulation amount measurement element. Figure 21 is a schematic top view showing an example of the size and arrangement position of the phase modulation amount measurement element and light shielding layer in the configuration example of Figure 20. Figure 22 is a schematic cross-sectional view showing a modified example of the self-interference configuration 6 of Figure 20.Figure 23 is a schematic top view showing an example of the size and placement of the phase modulation amount measuring element 60 and the light-shielding layer 61 in the configuration example of Figure 22. Figure 24 is a schematic top view showing an example of the size and placement of the phase modulation amount measuring element 60 and the light-shielding layer 61 in the configuration example of Figure 22. Figure 25 is a schematic cross-sectional view showing a polarizing plate type configuration example 1 as an example of the configuration of the phase modulation amount measuring element. Figure 26 is an explanatory diagram showing an example of the relationship between the measured value of the phase modulation amount measuring element and the phase modulation amount by the optical modulation layer. Figure 27 is a schematic top view showing a first example of the size and placement of the phase modulation amount measuring element and polarizing plate in the configuration example of Figure 25. Figure 28 is a schematic top view showing a second example of the size and placement of the phase modulation amount measuring element and polarizing plate in the configuration example of Figure 25. Figure 29 is a schematic top view showing a third example of the size and placement of the phase modulation amount measuring element and polarizing plate in the configuration example of Figure 25. Figure 30 is a schematic cross-sectional view showing a polarizer-type configuration example 2 as an example of the configuration of a phase modulation amount measuring element. Figure 31 is a schematic cross-sectional view showing a polarizer-type configuration example 3 as an example of the configuration of a phase modulation amount measuring element. Figure 32 is a schematic plan view showing a first example of the arrangement location of the phase modulation amount measuring element. Figure 33 is a schematic plan view showing a second example of the arrangement location of the phase modulation amount measuring element. Figure 34 is a schematic plan view showing a third example of the arrangement location of the phase modulation amount measuring element. Figure 35 is a schematic plan view showing a fourth example of the arrangement location of the phase modulation amount measuring element. Figure 36 is a schematic plan view showing a fifth example of the arrangement location of the phase modulation amount measuring element. Figure 37 is a schematic plan view showing a sixth example of the arrangement location of the phase modulation amount measuring element. Figure 38 is a configuration diagram showing an example of a spatial light modulator according to a modified embodiment. Figure 39 is a plan view showing an example of the electrode structure of the opposing substrate in a spatial light modulator according to a modified embodiment. Figure 40 is a plan view showing an example of the electrode structure of a pixel substrate in a modified spatial light modulator.

[0009] The embodiments of this disclosure will be described in detail below with reference to the drawings. The description will be in the following order: 0. Comparative Examples 1. One Embodiment 1.1 Overview 1.2 Example Configuration of Phase Modulation Measurement Element 1.2.1 Self-Interference Method 1.2.2 Polarizing Plate Method 1.2.3 Placement of Phase Modulation Measurement Element 1.3 Modified Examples 1.4 Effects 2. Other Embodiments

[0010] <0. Comparative Example> (Overview of a Phase-Modulated Spatial Light Modulator (SLM)) Figure 1 shows an overview of the dielectric anisotropy of liquid crystals. Figure 2 shows an overview of the refractive index anisotropy of liquid crystals. Figure 3 shows an overview of a phase-modulated spatial light modulator.

[0011] Liquid crystals exhibit dielectric anisotropy. As shown in Figure 1, when an electric field E is applied to liquid crystal molecules 100, the case where the major axis is parallel to the direction of the electric field is called positive dielectric anisotropy, and the case where the minor axis is parallel is called negative dielectric anisotropy. Furthermore, liquid crystals exhibit refractive index anisotropy, where the refractive index differs depending on the direction of the liquid crystal molecules 100. As shown in Figure 2, when the refractive index in the direction parallel to the major axis of the liquid crystal molecule 100 is denoted as ne and the refractive index in the direction parallel to the minor axis of the liquid crystal molecule 100 is denoted as no, then ne > no, and the difference between refractive index ne and refractive index no is called refractive index anisotropy Δn (= ne - no). This refractive index anisotropy causes a phase difference in light depending on the direction of incidence.

[0012] A phase-modulation type spatial light modulator is a device that modulates only the phase of light by utilizing the properties of liquid crystals described above. Figure 3 shows an example configuration of a reflective type spatial light modulator. Figure 3 also shows an example where the liquid crystal molecules 100 are composed of a liquid crystal material having negative dielectric anisotropy.

[0013] The spatial light modulator has a structure in which a liquid crystal layer containing liquid crystal molecules 100 is sandwiched between a common electrode 111 and a pixel electrode 121 that are positioned opposite each other. The common electrode 111 is a transparent electrode, and an alignment film is formed on the surface facing the liquid crystal layer. A reflective film and an alignment film are formed on the surface facing the liquid crystal layer of the pixel electrode 121.

[0014] The liquid crystal molecules 100 are given a pre-tilt angle. If the liquid crystal molecules 100 have negative dielectric anisotropy, when no voltage is applied between the common electrode 111 and the pixel electrode 121 (voltage OFF), the liquid crystal molecules 100 are in an upright position at the pre-tilt angle. When a voltage is applied between the common electrode 111 and the pixel electrode 121 (voltage ON), the liquid crystal molecules 100 tilt. Therefore, the reflected light L21 from the pixel electrode 121 when the voltage is OFF and the reflected light L22 from the pixel electrode 121 when the voltage is ON have different states of liquid crystal molecules 100 as the light passes through them, resulting in a phase difference between them. As a result, the spatial light modulator can control the phase of the incident light L1 analogously by controlling the voltage applied to the liquid crystal layer.

[0015] (Applications of SLM) Because it is possible to modulate the phase of light and realize various functions through light interference, SLM has a wide range of applications. Examples of display applications include holographic stereoscopic displays and high-efficiency projectors. In industrial equipment applications, for example, it is used for irradiation shape modulation and aberration correction in laser processing machines, and in laser markers. In communications applications, for example, it is used in wavelength selective switches (WSS).

[0016] (Performance required for SLM) It is desirable for SLMs to modulate the phase with high precision. For example, when used for aberration correction, a deviation in the phase modulation amount can cause new aberrations. Also, if there is an error in the modulation amount, the interference conditions will differ from the desired conditions, resulting in decreased efficiency or increased noise. However, SLMs have errors in the phase modulation amount due to various factors. Examples include changes in optical and electrical performance due to material degradation of the optical modulation material (liquid crystal, etc.), electrical drift caused by the drive circuit, and the difference between the design wavelength and the actual operating wavelength. In principle, it is possible to detect and correct for various factors, but this complicates the device structure and control. It is simpler and possible to reduce errors by directly observing the state of the light being modulated by the SLM.

[0017] (Challenges in observing phase modulation) Measuring the intensity of light is easy, but directly observing the phase of light is generally difficult. This is because the output of photodiodes, etc., does not change simply because the phase of light changes. Methods for observing the phase of light include observing the polarization state of light and using an interferometer to convert the phase of light into light intensity, but these require preparing a dedicated optical system outside the SLM, which is cumbersome.

[0018] Therefore, the development of a spatial light modulator capable of performing high-precision phase modulation is desired.

[0019] <1. One Embodiment> [1.1 Overview] Figure 4 is a schematic block diagram showing a first configuration example of a spatial light modulator 1 according to one embodiment.

[0020] The spatial light modulator 1 according to the first configuration example comprises a signal processing circuit 50, a phase modulation amount measuring element 60, and a pixel P. The pixel P has a common electrode 11 and a pixel electrode 21.

[0021] The phase modulation amount measuring element 60 may be, for example, a photodiode. The phase modulation amount measuring element 60 is a measuring element for measuring the amount of phase modulation by the optical modulation layer 30 (Figure 6), which will be described later, by measuring the light intensity of the light that has passed through the optical modulation layer 30.

[0022] The signal processing circuit 50 generates an output signal to the pixel P according to the input signal. The signal processing circuit 50 includes a correction circuit 51. The correction circuit 51 corrects the output value Vsig (voltage applied to the pixel electrode 21) of the output signal to the pixel P based on the measured value Da of the phase modulation amount measuring element 60. The correction circuit 51 may have a lookup table that shows the correspondence between the measured value Da and the correction amount of the output signal to the pixel P.

[0023] Figure 5 is a schematic block diagram showing a second configuration example of a spatial light modulator 1 according to one embodiment.

[0024] The spatial light modulator 1 according to the second configuration example comprises a signal processing circuit 50, a common voltage control circuit 52, a phase modulation amount measuring element 60, and a pixel P. The pixel P has a common electrode 11 and a pixel electrode 21.

[0025] The common voltage control circuit 52 controls the common voltage Vcom (voltage applied to the common electrode 11). The common voltage control circuit 52 has a correction circuit 53. The correction circuit 53 corrects the common voltage Vcom (voltage applied to the common electrode 11) based on the measured value Da of the phase modulation amount measuring element 60.

[0026] In addition, in the spatial light modulator 1 according to one embodiment, both the output value Vsig to the pixel P and the common voltage Vcom may be corrected based on the measured value Da of the phase modulation amount measuring element 60.

[0027] Other configurations and operations may be substantially the same as those of the spatial light modulator 1 according to one embodiment shown in Figure 4 above.

[0028] (Example of Pixel Structure Configuration) Figure 6 is a schematic cross-sectional view showing an example of the pixel structure of a spatial light modulator 1 according to one embodiment. Although Figure 6 shows an example of a pixel structure for two pixels (pixel A and pixel B), the spatial light modulator 1 according to one embodiment may have a plurality of pixels P arranged in a matrix in two dimensions. Figure 6 shows an example of incident light L1, which is incident light L1A to pixel A as the first pixel and incident light L1B to pixel B as the second pixel.

[0029] A spatial light modulator 1 according to one embodiment comprises a first substrate, which is an opposing substrate 10, and a second substrate, which is a pixel substrate 20, both located on the light incident side. The pixel substrate 20 is positioned opposite the opposing substrate 10 so as to sandwich the light modulation layer 30 between itself and the opposing substrate 10.

[0030] The optical modulation layer 30 may be a liquid crystal layer containing a plurality of liquid crystal molecules 100 having the same structure as those shown in Figures 1 to 3 above. However, the optical modulation layer 30 is not limited to a structure using liquid crystal molecules 100, but may also be a structure using a phase change material.

[0031] The opposing substrate 10 is made of an optically transparent material such as glass or transparent resin. A common electrode (opposing electrode) 11 made of transparent electrodes is formed over the entire surface of at least the effective pixel region of the opposing substrate 10. The common electrode 11 is made of a transparent conductive film such as an ITO (Indium Tin Oxide) film. An alignment film 12 is formed over the entire surface of at least the effective pixel region between the common electrode 11 and the optical modulation layer 30. The alignment film 12 is made of, for example, a vapor-deposited film of an inorganic material or an organic film obtained by rubbing an organic material such as polyimide.

[0032] The pixel substrate 20 is made of, for example, a TFT (Thin Film Transistor) substrate. Multiple pixel electrodes 21 are formed in the effective pixel region of the pixel substrate 20. The multiple pixel electrodes 21 are arranged, for example, in a matrix. In addition, an alignment film 22 is formed over the entire surface of at least the effective pixel region between the multiple pixel electrodes 21 and the optical modulation layer 30. The alignment film 22 is made of, for example, a vapor-deposited film of an inorganic material, or an organic film obtained by rubbing an organic material such as polyimide. The pixel substrate 20 has a pixel circuit. Each of the multiple pixel electrodes 21 is connected to the pixel circuit via 23.

[0033] The amount of phase modulation at pixel P changes according to the output value Vsig (voltage applied to the pixel electrode 21) and the common voltage Vcom (voltage applied to the common electrode 11) of the output signal to pixel P. Therefore, the correction circuit 51 (Figure 4) can correct the amount of phase modulation at pixel P by correcting the output value Vsig of the output signal to pixel P based on the measured value Da of the phase modulation amount measuring element 60. In addition, the correction circuit 53 (Figure 5) can correct the amount of phase modulation at pixel P by correcting the common voltage Vcom based on the measured value Da of the phase modulation amount measuring element 60.

[0034] In one embodiment, the spatial light modulator 1 may be of the reflective type or the transmissive type. In the case of a reflective configuration, the pixel electrode 21 is composed of a reflective electrode, and for example, a reflective film that reflects light is formed on the surface of the pixel electrode 21 facing the light modulation layer 30. In the case of a transmissive configuration, the pixel electrode 21 is composed of a transparent electrode that transmits light.

[0035] Furthermore, the spatial light modulator 1 according to one embodiment may have a lateral electric field drive configuration. In this case, the common electrode 11 may be placed on the pixel substrate 20 side.

[0036] [1.2 Example of Phase Modulation Amount Measurement Element Configuration] The phase modulation amount measurement element 60 may be a measurement element for measuring the amount of phase modulation by the optical modulation layer 30 by measuring the light intensity after causing the first light and the second light from two different pixels P that have passed through the optical modulation layer 30 to self-interfere. Hereinafter, a method of measuring the amount of phase modulation by the optical modulation layer 30 using such self-interference of light will be referred to as the self-interference method.

[0037] Furthermore, the phase modulation amount measuring element 60 may be a measuring element for measuring the amount of phase modulation by the optical modulation layer 30 by measuring the light intensity of the light that has passed through the optical modulation layer 30 via a polarizing plate 81 acting as an analyzer, as shown in Figure 25 and other figures described later. Hereinafter, a method for measuring the amount of phase modulation using such a polarizing plate 81 will be referred to as the polarizing plate method.

[0038] Below, we will describe, in order, an example configuration of the phase modulation amount measuring element 60, specifically a self-interference type configuration and a polarizing plate type configuration.

[0039] [1.2.1 Self-Interference Method] (Example 1 of Self-Interference Method Configuration) Figure 7 is a schematic cross-sectional view showing Example 1 of the Self-Interference Method Configuration as an example of the configuration of the phase modulation amount measuring element 60.

[0040] In the configuration example shown in Figure 7, a phase modulation amount measuring element 60 is arranged within the pixel substrate 20. In the configuration example shown in Figure 7, the phase modulation amount measuring element 60 measures the amount of phase modulation by the optical modulation layer 30 by measuring the light intensity after causing self-interference between a first light and a second light from two adjacent pixels P (corresponding to pixels A and B). The phase modulation amount measuring element 60 is positioned to receive the first light and the second light from two adjacent pixels P (corresponding to pixels A and B). The arrangement area of ​​the phase modulation amount measuring element 60 includes, for example, the area corresponding to the area between the two pixel electrodes 21 that constitute the two adjacent pixels A and B. The pixel electrodes 21 used for measuring the amount of phase modulation may be electrodes of the same size as the pixel electrodes 21 that constitute a normal pixel P, or electrodes of a different size from the pixel electrodes 21 that constitute a normal pixel P may be used.

[0041] Furthermore, if the spatial light modulator 1 according to one embodiment is configured as a reflective type (where the pixel electrodes 21 are composed of reflective electrodes), then only the portion of the pixel electrodes 21 corresponding to the area where the phase modulation amount measuring element 60 is located should be transmissive or semi-transmissive.

[0042] Figure 8 is an explanatory diagram showing an example of the relationship between the measured value Da of the phase modulation amount measuring element 60 and the phase modulation amount by pixel B. In Figure 8, the vertical axis represents the measured value Da (normalized detection intensity), and the horizontal axis represents the difference (phase difference) (pi rad) between the phase modulation amount by pixel A and the phase modulation amount by pixel B.

[0043] For example, by using the light emitted from pixel A as the reference light and the light emitted from pixel B, which is the pixel to be measured, as the modulated light, and reading the measured value Da of the phase modulation amount measuring element 60 while changing the output value Vsig to pixel B, it becomes possible to obtain the relationship between the output value Vsig to pixel B and the phase modulation amount by pixel B.

[0044] When performing measurement with the phase modulation amount measuring element 60, the output value Vsig of pixel B, which is the measurement target pixel, may be fixed to a specific value. For example, assume that the phase modulation amount of pixel A, which is the reference pixel, is 0 rad, and the phase modulation amount of pixel B, which is the measurement target pixel, is pi rad. In this case, for example, a method is also possible in which the output value Vsig to pixel B and the common voltage Vcom are corrected such that the measured value Da of the phase modulation amount measuring element 60 is minimized, and grayscales other than pi rad are interpolated with an appropriate curve. Especially when correcting only the common voltage Vcom, control becomes simpler compared to the case of correcting the voltage applied to the pixel electrode 21.

[0045] FIG. 9 is a top view schematically illustrating a first example of the size and arrangement position of the phase modulation amount measuring element 60 in the configuration example of FIG. 7. FIG. 10 is a top view schematically illustrating a second example of the size and arrangement position of the phase modulation amount measuring element 60 in the configuration example of FIG. 7. FIG. 11 is a top view schematically illustrating a third example of the size and arrangement position of the phase modulation amount measuring element 60 in the configuration example of FIG. 7. FIGS. 9 to 11 show an example in which the planar shapes of the pixel electrode 21 and the phase modulation amount measuring element 60 are quadrangular. However, the planar shapes of the pixel electrode 21 and the phase modulation amount measuring element 60 are not limited to being quadrangular.

[0046] The phase modulation amount measuring element 60 is arranged in a region that partially overlaps two adjacent pixel electrodes 21 (corresponding to pixel A and pixel B) in a plan view. FIG. 9 shows a configuration example in which the planar shapes of the pixel electrode 21 and the phase modulation amount measuring element 60 are substantially square, and the width of one side of the phase modulation amount measuring element 60 is smaller than the width of one side of the pixel electrode 21. FIG. 10 shows a configuration example in which the planar shapes of the pixel electrode 21 and the phase modulation amount measuring element 60 are substantially square, and the width of one side of the pixel electrode 21 is substantially equal to the width of one side of the phase modulation amount measuring element 60. FIG. 11 shows a configuration example in which the planar shapes of the pixel electrode 21 and the phase modulation amount measuring element 60 are substantially rectangular, and the width of one side of the phase modulation amount measuring element 60 is smaller than the width of one side of the pixel electrode 21.

[0047] FIG. 12 is a cross-sectional view schematically showing an example of the sizes and installation positions of a phase modulation amount measurement element 60 and pixel electrodes 21 in the configuration example of FIG. 7.

[0048] The inter-electrode distance between two adjacent pixel electrodes 21 (corresponding to a pixel A and a pixel B) is preferably, for example, 0.15 µm or more and 10 µm or less. When the installation position of the phase modulation amount measurement element 60 (the distance from the lower surface of the pixel electrode 21) is assumed to be 10 µm, the upper limit of the inter-electrode distance is preferably 10 µm or less in order to make the angle of light during interference approximately 45° or less. The lower limit of the inter-electrode distance is preferably 0.15 µm or more from the range that can be manufactured by semiconductor process technology. Regarding the installation position of the phase modulation amount measurement element 60, as the distance from the lower surface of the pixel electrode 21 to the upper surface of the phase modulation amount measurement element 60, in consideration of the distance that can be installed by semiconductor process technology, the distance is preferably 2 µm or more and 10 µm or less.

[0049] Other configurations and operations may be substantially the same as the configuration and operation of the spatial light modulator 1 according to the embodiment shown in FIG. 6 above.

[0050] (Configuration Example 2 of Self-Interference Method) FIG. 13 is a cross-sectional view schematically showing Configuration Example 2 of the self-interference method as a configuration example of a phase modulation amount measurement element 60.

[0051] In the configuration example of FIG. 13, a light condensing element 71 is further provided compared to the configuration example of FIG. 7 described above. The light condensing element 71 is disposed between the pixel electrode 21 and the phase modulation amount measurement element 60 in a pixel substrate 20, and is an optical member that condenses first light and second light from two pixels P (corresponding to a pixel A and a pixel B) used for measuring a phase modulation amount toward the phase modulation amount measurement element 60. The light condensing element 71 is, for example, a microlens having a convex lens shape. The light condensing element 71 is made of a material (e.g., SiN) having a higher refractive index than the material of the pixel substrate 20 (e.g., SiO). By disposing the light condensing element 71, the light from the pixel A and the pixel B can be efficiently condensed onto the light condensing element 71.

[0052] FIG. 14 is a cross-sectional view schematically showing a modified example of Configuration Example 2 of the self-interference method of FIG. 13.

[0053] In the configuration example shown in Figure 14, a light-collecting member 72 is provided as an optical element instead of the light-collecting element 71 in the configuration example shown in Figure 13. If it is difficult to form a lens-shaped light-collecting element 71 within the pixel substrate 20 for manufacturing purposes, a rectangular light-collecting member 72 made of a material with a higher refractive index (e.g., SiN) than the material of the pixel substrate 20 (e.g., SiO) may be stacked and arranged as shown in the configuration example in Figure 14.

[0054] Other configurations and operations may be substantially the same as those of the self-interference method configuration example 1 shown in Figures 7 to 11 above.

[0055] (Example 3 of the self-interference method configuration) Figure 15 is a schematic cross-sectional view showing Example 3 of the self-interference method configuration as an example of the configuration of the phase modulation amount measuring element 60.

[0056] In the configuration example shown in Figure 15, compared to the configuration example in Figure 7, an opening (hole) 24 is provided in a part (for example, approximately in the center) of the pixel electrode 21 used for measuring the phase modulation amount. In the configuration example in Figure 15, the pixel electrode 21 corresponding to pixel A is provided with an opening 24 (first opening) through which the first light from pixel A can pass, and the pixel electrode 21 corresponding to pixel B is provided with an opening 24 (second opening) through which the second light from pixel B can pass. In the configuration example in Figure 15, the first and second light from the two pixels P (corresponding to pixels A and B) used for measuring the phase modulation amount are diffracted by the opening 24 and focused toward the phase modulation amount measuring element 60. In the configuration example in Figure 15, for example, by measuring the phase modulation amount using light passing through approximately in the center of the pixel electrode 21, the measurement accuracy can be improved. In particular, even if the spatial light modulator 1 according to one embodiment is a reflective type and the pixel electrode 21 is composed of a reflective electrode, the phase modulation amount can be easily measured in the phase modulation amount measuring element 60.

[0057] Figure 16 is a schematic cross-sectional view showing an example of the size and placement of the aperture 24 of the pixel electrode 21 in the configuration example shown in Figure 15.

[0058] In the configuration example shown in Figure 15, the distance between the apertures 24 of two adjacent pixel electrodes 21 used for measuring the phase modulation amount is preferably between the centers of the apertures 24, for example, 0.3 μm or more and 10 μm or less. In this case, the upper limit is preferably 10 μm or less in relation to the installation position of the phase modulation amount measuring element 60 (distance from the lower surface of the electrode of the pixel electrode 21) in order to keep the angle between the two interfering lights approximately 45 degrees or less. The lower limit is preferably 0.3 μm or more, within the range that can be manufactured using semiconductor process technology.

[0059] Furthermore, the diameter of the aperture 24 of the pixel electrode 21 should be, for example, 150 nm or more and 2 μm or less. In this case, the upper limit is 2 μm or less, which is the diameter that has little effect on the electric field distribution when the thickness of the optical modulation layer 30 is at most about 20 μm. The lower limit is 150 nm or more, which is within the range that can be fabricated using semiconductor process technology.

[0060] Other configurations and operations may be substantially the same as those of the self-interference method configuration example 1 shown in Figures 7 to 11 above.

[0061] (Example of Self-Interference Configuration 4) Figure 17 is a schematic cross-sectional view showing Example of Self-Interference Configuration 4 as an example of the configuration of the phase modulation amount measuring element 60. Figure 18 is a cross-sectional view showing an example of the wavefront state of the incident light L1 to the spatial light modulator 1 in Figure 17. Figure 18 also shows an example of the wavefront state when the optical modulation state in the optical modulation layer 30 is a low refractive index state for pixel A and a high refractive index state for pixel B.

[0062] The position of the phase modulation amount measuring element 60 is not limited to a position corresponding to the space between two adjacent pixel electrodes 21 used for measuring the phase modulation amount, but may also be a position corresponding to either one of the two adjacent pixel electrodes 21. In the configuration example shown in Figure 17, the phase modulation amount measuring element 60 is positioned at a location corresponding to the pixel electrode 21 of pixel B. As shown in Figure 18, light behaves to concentrate on the side with a higher refractive index. Therefore, by positioning the phase modulation amount measuring element 60 at a location corresponding to the pixel electrode 21 of pixel B, and by setting pixel A to a low refractive index state and pixel B to a high refractive index state, a portion of the incident light L1A to pixel A and a portion of the incident light L1A to pixel B can be received by the phase modulation amount measuring element 60.

[0063] Other configurations and operations may be substantially the same as those of the self-interference method configuration example 1 shown in Figures 7 to 11 above.

[0064] (Example 5 of the self-interference method configuration) Figure 19 is a schematic cross-sectional view showing Example 5 of the self-interference method configuration as an example of the configuration of the phase modulation amount measuring element 60.

[0065] The number of phase modulation amount measuring elements 60 may be multiple. By installing multiple phase modulation amount measuring elements 60, the amount of phase modulation by the optical modulation layer 30 may be measured from the ratio of multiple measured values ​​Da obtained by multiple phase modulation amount measuring elements 60. In the configuration example of Figure 19, compared to the configuration example of Figure 17, an example is shown in which the phase modulation amount measuring elements 60 include a first measuring element positioned at a location corresponding to the pixel electrode 21 of pixel A and a second measuring element positioned at a location corresponding to the pixel electrode 21 of pixel B. In this case, the amount of light phase modulation by the optical modulation layer 30 can be measured based on a first measured value obtained by the first measuring element and a second measured value obtained by the second measuring element.

[0066] Other configurations and operations may be substantially the same as those of the self-interference configuration example 4 shown in Figure 17 above.

[0067] (Example 6 of the self-interference method configuration) Figure 20 is a schematic cross-sectional view showing Example 6 of the self-interference method configuration as an example of the configuration of the phase modulation amount measuring element 60.

[0068] In the configuration example shown in Figure 20, compared to the configuration example in Figure 7, a light-shielding layer 61 is provided between the phase modulation amount measuring element 60 and two adjacent pixels P (pixel A and pixel B) used for measuring the phase modulation amount, at a position corresponding to the space between the two pixel electrodes 21 of the two adjacent pixels P. In the configuration example shown in Figure 20, by shielding the light passing between the two adjacent pixels used for measuring the phase modulation amount with the light-shielding layer 61, optical noise during the measurement of the phase modulation amount can be reduced.

[0069] Figure 21 is a schematic top view showing an example of the size and arrangement of the phase modulation amount measuring element 60 and the light-shielding layer 61 in the configuration example shown in Figure 20. Figure 21 shows an example where the planar shape of the light-shielding layer 61, the pixel electrode 21, and the phase modulation amount measuring element 60 is rectangular. However, the planar shape of the light-shielding layer 61, the pixel electrode 21, and the phase modulation amount measuring element 60 is not limited to a rectangular shape.

[0070] The light-shielding layer 61 and the phase modulation amount measuring element 60 are arranged in a region that partially overlaps two adjacent pixel electrodes 21 (corresponding to pixels A and B) when viewed from above. Figure 21 shows an example configuration where the planar shape of the pixel electrodes 21 and the phase modulation amount measuring element 60 is approximately square, and the width of one side of the phase modulation amount measuring element 60 is smaller than the width of one side of the pixel electrodes 21. Figure 21 also shows an example configuration where, when viewed from above, the width of one side of the pixel electrodes 21 and the width of one side of the light-shielding layer 61 are approximately equal, and the overall size of the light-shielding layer 61 is larger than the size of the phase modulation amount measuring element 60.

[0071] Other configurations and operations may be substantially the same as those of the self-interference method configuration example 1 shown in Figures 7 to 11 above.

[0072] Figure 22 is a schematic cross-sectional view showing a modified example of the self-interference method configuration 6 in Figure 20.

[0073] In the configuration example shown in Figure 22, a light-shielding layer 61 is provided at a position corresponding to the space between two adjacent pixel electrodes 21 used for measuring the phase modulation amount, compared to the configuration example shown in Figure 15. In the configuration example shown in Figure 22, by shielding the light passing between two adjacent pixels used for measuring the phase modulation amount with the light-shielding layer 61, optical noise during the measurement of the phase modulation amount can be reduced.

[0074] Figures 23 and 24 are schematic top views showing an example of the size and arrangement of the phase modulation amount measuring element 60 and the light-shielding layer 61 in the configuration example shown in Figure 22. Figures 23 and 24 show an example where the planar shape of the light-shielding layer 61, the pixel electrode 21, and the phase modulation amount measuring element 60 is rectangular. However, the planar shape of the light-shielding layer 61, the pixel electrode 21, and the phase modulation amount measuring element 60 is not limited to a rectangular shape.

[0075] The light-shielding layer 61 and the phase modulation amount measuring element 60 are positioned in a region that partially overlaps two adjacent pixel electrodes 21 (corresponding to pixels A and B) when viewed from above. Figures 23 and 24 show an example configuration where the planar shape of the pixel electrodes 21 and the phase modulation amount measuring element 60 is approximately square, and the width of one side of the phase modulation amount measuring element 60 is smaller than the width of one side of the pixel electrodes 21. Figures 23 and 24 also show an example configuration where, when viewed from above, the width of one side of the pixel electrodes 21 and the width of one side of the light-shielding layer 61 are approximately equal, and the overall size of the light-shielding layer 61 is larger than the size of the phase modulation amount measuring element 60.

[0076] Furthermore, in a plan view, the shape of the opening 24 provided in a part of the pixel electrode 21 is not limited to a circular shape (Figure 23), but may also be a rectangular shape (Figure 24).

[0077] Other configurations and operations may be substantially the same as those of the self-interference configuration example 3 shown in Figure 15 above.

[0078] [1.2.2 Polarizing Plate Method] (Example 1 of Polarizing Plate Method Configuration) Figure 25 is a schematic cross-sectional view showing Example 1 of the polarizing plate method configuration as an example of the configuration of the phase modulation amount measuring element 60. Figure 25 shows an example in which the light intensity of the light after modulation of the incident light L1A to pixel A is measured by the phase modulation amount measuring element 60 via a polarizing plate 81 acting as an analyzer.

[0079] In the configuration example shown in Figure 25, a phase modulation amount measuring element 60 is arranged within the pixel substrate 20. Furthermore, at a position corresponding to pixel A, a λ / 2 plate 82 is positioned on the light incident side of the optical modulation layer 30 as a waveplate. Also at a position corresponding to pixel A, a polarizing plate 81 is positioned on the light exit side of the optical modulation layer 30 as a first polarizing plate. In order from the light incident side, the polarizing plate 81, the λ / 2 plate 82, and the phase modulation amount measuring element 60 are arranged in at least a portion of the region corresponding to the pixel electrode 21 of pixel A used for measuring the phase modulation amount. The phase modulation amount measuring element 60 is positioned to receive light from pixel A used for measuring the phase modulation amount.

[0080] The λ / 2 plate 82 rotates the polarization direction of the incident light so that it is linearly polarized at 45° with respect to the orientation of the optical modulation layer 30. The polarization angle of the polarizer 81 may be, for example, 135°. If the optical modulation layer 30 is a liquid crystal layer, the lagging axis of the λ / 2 plate 82 can be any angle as long as it does not coincide with the lagging or leading axis of the liquid crystal molecules, but a value of 22.5° with respect to the lagging or leading axis of the liquid crystal molecules is preferable from the viewpoint of signal-to-noise ratio because it provides the best contrast. The λ / 2 plate 82 does not require high precision. If the output value of the phase modulation amount measuring element 60 at the time of shipment is saved, the phase modulation amount can be corrected by taking into account the error from the ideal waveplate.

[0081] Figure 26 is an explanatory diagram showing an example of the relationship between the measured value Da of the phase modulation amount measuring element 60 and the phase modulation amount by the optical modulation layer 30. In Figure 26, the vertical axis represents the measured value Da (normalized detection intensity), and the horizontal axis represents the phase modulation amount (phase difference) (pi rad).

[0082] For example, by using the light emitted from pixel A as modulated light and reading the measured value Da of the phase modulation amount measuring element 60 while changing the output value Vsig to pixel A (voltage applied to the pixel electrode 21), it becomes possible to obtain the relationship between the output value Vsig to pixel A and the amount of phase modulation by pixel A. In this case, for example, the output value Vsig to pixel A and the common voltage Vcom are corrected so that the measured value Da of the phase modulation amount measuring element 60 becomes a desired value.

[0083] Figure 27 is a schematic top view showing a first example of the size and arrangement of the phase modulation amount measuring element 60 and polarizer 81 in the configuration example of Figure 25. Figure 28 is a schematic top view showing a second example of the size and arrangement of the phase modulation amount measuring element 60 and polarizer 81 in the configuration example of Figure 25. Figure 29 is a schematic top view showing a third example of the size and arrangement of the phase modulation amount measuring element 60 and polarizer 81 in the configuration example of Figure 25. Figures 27 to 29 show examples where the planar shape of the polarizer 81, pixel electrode 21 and phase modulation amount measuring element 60 is rectangular. However, the planar shape of the polarizer 81, pixel electrode 21 and phase modulation amount measuring element 60 is not limited to a rectangular shape.

[0084] The phase modulation amount measuring element 60 is positioned in a region that overlaps with at least a portion of the pixel electrode 21 (corresponding to pixel A) used for measuring the phase modulation amount when viewed from above. Figures 27 and 28 show an example configuration when the planar shapes of the polarizer 81, pixel electrode 21, and phase modulation amount measuring element 60 are approximately square when viewed from above. Figure 27 also shows an example configuration when the size of the planar shape of the polarizer 81 is smaller than that of the pixel electrode 21 when viewed from above, and the size of the phase modulation amount measuring element 60 is even smaller than that of the polarizer 81. Figure 28 shows an example configuration when the size of the planar shapes of the polarizer 81 and phase modulation amount measuring element 60 are approximately the same as that of the pixel electrode 21 when viewed from above. Figure 29 shows an example configuration when the planar shapes of the polarizer 81, pixel electrode 21, and phase modulation amount measuring element 60 are approximately rectangular when viewed from above. Furthermore, Figure 29 shows an example configuration in which, when viewed from above, the size of the planar shape of the polarizing plate 81 is smaller than that of the pixel electrode 21, and the size of the phase modulation amount measuring element 60 is even smaller than that of the polarizing plate 81.

[0085] Other configurations and operations may be substantially the same as those of the spatial light modulator 1 according to one embodiment shown in Figure 6 above.

[0086] (Polarizing plate configuration example 2) Figure 30 is a schematic cross-sectional view showing polarizing plate configuration example 2 as an example of the configuration of the phase modulation amount measuring element 60.

[0087] In the configuration example shown in Figure 30, a polarizing plate 83 is installed on the light incident side of the optical modulation layer 30 in place of the λ / 2 plate 82, acting as a second polarizing plate, compared to the configuration example shown in Figure 25. The polarization angles of the polarizing plate 81 on the light emission side and the polarizing plate 83 on the light incident side are arbitrary. However, from the viewpoint of the signal-to-noise ratio, a crossed nicol configuration is desirable. For example, the polarization angle of the polarizing plate 81 on the light emission side may be 135°, and the polarization angle of the polarizing plate 83 on the light incident side may be 45°.

[0088] Other configurations and operations may be substantially the same as those of the polarizing plate configuration example 1 shown in Figures 25 to 29 above.

[0089] (Polarizing plate configuration example 3) Figure 31 is a schematic cross-sectional view showing polarizing plate configuration example 3 as an example of the configuration of the phase modulation amount measuring element 60.

[0090] In the configuration example shown in Figure 31, the λ / 2 plate 82 is omitted compared to the configuration example in Figure 25. For example, if the optical modulation layer 30 is a liquid crystal layer, the orientation of the liquid crystal may be partially changed only for the pixel P (pixel A in the configuration example of Figure 31) used to measure the amount of phase modulation (for example, 45°). This makes it possible to modulate the polarization state of the incident light and measure the amount of phase modulation with the phase modulation amount measuring element 60 without placing the λ / 2 plate 82 (Figure 25) or polarizer 83 (Figure 30) on the light incident side of the optical modulation layer 30.

[0091] Other configurations and operations may be substantially the same as those of the polarizing plate configuration example 1 shown in Figures 25 to 29 above.

[0092] [1.2.3 Placement of Phase Modulation Amount Measurement Element] Figure 32 is a schematic plan view showing a first example of the placement of the phase modulation amount measurement element 60. Figure 33 is a schematic plan view showing a second example of the placement of the phase modulation amount measurement element 60.

[0093] As shown in Figure 32, in the spatial light modulator 1 according to one embodiment, the phase modulation amount measuring element 60 may be arranged in a region outside the effective pixel region 200. Also, as shown in Figure 33, multiple phase modulation amount measuring elements 60 may be arranged in the region outside the effective pixel region 200. When multiple phase modulation amount measuring elements 60 are arranged, the correction amount of the output value Vsig to the pixel P or the common voltage Vcom may be determined based on multiple measurement values ​​Da obtained from the multiple phase modulation amount measuring elements 60. When the phase modulation amount measuring elements 60 are arranged in a region outside the effective pixel region 200, pixels for measuring the phase modulation amount are arranged in the region outside the effective pixel region 200.

[0094] Figure 34 is a schematic plan view showing a third example of the arrangement of the phase modulation amount measuring element 60. Figure 35 is a schematic plan view showing a fourth example of the arrangement of the phase modulation amount measuring element 60.

[0095] As shown in Figure 34, in the spatial light modulator 1 according to one embodiment, the phase modulation amount measuring element 60 may be arranged in the region inside the effective pixel area 200. Also, as shown in Figure 34, multiple phase modulation amount measuring elements 60 may be arranged in the region inside the effective pixel area 200. When multiple phase modulation amount measuring elements 60 are arranged, the correction amount of the output value Vsig to the pixel P or the common voltage Vcom may be determined based on multiple measurement values ​​Da obtained from the multiple phase modulation amount measuring elements 60. In particular, as shown in Figure 34, by arranging the phase modulation amount measuring element 60 near the center inside the effective pixel area 200, the measurement accuracy of the phase modulation amount can be improved. Also, as shown in Figure 35, by arranging multiple phase modulation amount measuring elements 60 and measuring the phase modulation amount at multiple points in the region inside the effective pixel area 200, the correction amount of the output value Vsig to the pixel P can be optimized according to the position. This makes it possible to correct unevenness throughout the entire effective pixel area 200. Furthermore, the measurement accuracy of the phase modulation amount can be further improved.

[0096] Furthermore, when controlling light interference by displaying a hologram (interference fringes) using the spatial light modulator 1 according to one embodiment, there is no practical problem even if a part of the pixel P is missing. For this reason, there is no practical problem even if the phase modulation amount measuring element 60 is placed in the area inside the effective pixel area 200.

[0097] Figure 36 is a schematic plan view showing a fifth example of the arrangement of the phase modulation amount measuring element 60. Figure 37 is a schematic plan view showing a sixth example of the arrangement of the phase modulation amount measuring element 60.

[0098] In one embodiment of the spatial light modulator 1, the effective pixel region 200 may have a slit portion 201, as shown in Figures 36 and 37. In this case, as shown in Figure 36, a phase modulation amount measuring element 60 may be placed in the slit portion 201. Alternatively, as shown in Figure 37, multiple phase modulation amount measuring elements 60 may be placed in the region outside the slit portion 201 and the effective pixel region 200. When multiple phase modulation amount measuring elements 60 are placed, the correction amount of the output value Vsig to the pixel P or the common voltage Vcom may be determined based on multiple measured values ​​Da obtained from the multiple phase modulation amount measuring elements 60. When the phase modulation amount measuring elements 60 are placed in the region outside the slit portion 201 and the effective pixel region 200, pixels for measuring the phase modulation amount are placed in the region outside the slit portion 201 and the effective pixel region 200.

[0099] [1.3 Modified Examples] Figure 38 is a configuration diagram showing an example of a spatial light modulator 1 according to a modified example of one embodiment. Figure 39 is a plan view showing an example of the electrode structure of the opposing substrate 10 in the spatial light modulator 1 according to a modified example. Figure 40 is a plan view showing an example of the electrode structure of the pixel substrate 20 in the spatial light modulator 1 according to a modified example.

[0100] In a spatial light modulator 1 according to one embodiment, the common electrode (counter electrode) 11 may have an electrode structure divided into multiple regions, and control may be performed so that a common voltage Vcom is applied independently to each of the multiple regions. Figures 38 to 40 show an example in which the common electrode (counter electrode) 11 has an electrode structure divided into divided electrode 11A, divided electrode 11B, divided electrode 11C, and divided electrode 11D. In the case of such an electrode structure, a phase modulation amount measuring element 60 may be placed in each region, and the correction amount of the output value Vsig to the pixel P or the common voltage Vcom may be determined based on the measured value Da obtained from the phase modulation amount measuring element 60 for each region. This makes it possible to perform high-precision phase modulation for each region.

[0101] [1.4 Effects] As described above, according to the spatial light modulator 1 of one embodiment, the phase modulation amount measuring element 60 measures the amount of phase modulation of light by the light modulation layer 30, making it possible to provide a spatial light modulator 1 that can perform highly accurate phase modulation.

[0102] According to one embodiment of the spatial light modulator 1, high-precision phase modulation is possible by feeding back the measured value Da of the phase modulation amount to the output signal to each pixel P. This enables high-precision phase modulation (automatic calibration). According to one embodiment of the spatial light modulator 1, errors in the modulation amount due to changes over time such as electrical drift and material degradation can be corrected. Furthermore, errors in the modulation amount caused by wavelength shifts of the light used can be corrected. In addition, malfunctions of the spatial light modulator 1 can be sensed.

[0103] The effects described herein are merely illustrative and not limiting, and other effects may also exist. The same applies to the effects of other embodiments described later.

[0104] <2. Other Embodiments> The technology described herein is not limited to the above-described embodiment and can be implemented in various modified forms.

[0105] For example, this technology can also take the following configuration. According to this configuration, the amount of phase modulation of light by the optical modulation layer is measured by a measuring element. This makes it possible to provide a spatial light modulator capable of high-precision phase modulation.

[0106] (1) A spatial light modulator comprising a plurality of pixels having an optical modulation layer that modulates the phase of incident light, and a measuring element that measures the amount of phase modulation of light by the optical modulation layer. (2) The spatial light modulator according to (1), further comprising a correction circuit that corrects the amount of phase modulation in each pixel based on a measurement value of the measuring element. (3) The spatial light modulator according to (2), wherein the plurality of pixels have a common electrode provided in common to the plurality of pixels and a pixel electrode provided for each of the plurality of pixels, and the correction circuit corrects the amount of phase modulation in each pixel by correcting at least one of the voltage applied to the pixel electrode and the voltage applied to the common electrode. (4) The spatial light modulator according to any one of (1) to (3), further comprising a counter substrate disposed on the light incident side, and a pixel substrate disposed opposite to the counter substrate so as to sandwich the optical modulation layer, and the measuring element disposed in the pixel substrate and measuring the light intensity of light that has passed through the optical modulation layer. (5) The spatial light modulator according to (4), wherein the plurality of pixels include a first pixel and a second pixel, and the measuring element measures the amount of phase modulation by the optical modulation layer by measuring the light intensity after interference between a first light from the first pixel that has passed through the optical modulation layer and a second light from the second pixel that has passed through the optical modulation layer. (6) The spatial light modulator according to (5), further comprising an optical member disposed in the pixel substrate for focusing the first light and the second light toward the measuring element. (7) The spatial light modulator according to (5), wherein each of the plurality of pixels has a pixel electrode, the pixel electrode corresponding to the first pixel is provided with a first aperture through which the first light can pass, the pixel electrode corresponding to the second pixel is provided with a second aperture through which the second light can pass, and the measuring element focuses the first light that has passed through the first aperture and the second light that has passed through the second aperture.(8) The spatial light modulator according to (5), wherein the measuring element is positioned at a location corresponding to the second pixel, and the optical modulation state in the first pixel is set to a low refractive index state and the optical modulation state in the second pixel is set to a high refractive index state, thereby receiving a portion of the incident light to the first pixel and a portion of the incident light to the second pixel at the measuring element. (9) The spatial light modulator according to (5), wherein the measuring element comprises a first measuring element positioned at a location corresponding to the first pixel and a second measuring element positioned at a location corresponding to the second pixel, and measures the amount of phase modulation of light by the optical modulation layer based on a first measurement value obtained by the first measuring element and a second measurement value obtained by the second measuring element. (10) The spatial light modulator according to (5), further comprising a light-shielding layer provided between the measuring element and the first and second pixels, at a position corresponding to the space between the first and second pixels, which shields light passing between the two pixels, the first and the second. (11) The spatial light modulator according to (4) above, further comprising a first polarizer plate as an analyzer disposed between one of the plurality of pixels and the measuring element, wherein the measuring element measures the amount of phase modulation by the optical modulation layer by measuring the light intensity of the light after modulation of the incident light to one of the plurality of pixels via the first polarizer plate. (12) The spatial light modulator according to (11) above, further comprising a wave plate disposed on the incident side of the optical modulation layer at a position corresponding to one of the plurality of pixels. (13) The spatial light modulator according to (11) above, further comprising a second polarizer plate disposed on the incident side of the optical modulation layer at a position corresponding to one of the plurality of pixels. (14) The spatial light modulator according to any one of (1) to (13) above, wherein the measuring element is disposed in one or more locations inside the effective pixel region. (15) The spatial light modulator according to any one of (1) to (13) above, wherein the measuring element is arranged in one or more regions outside the effective pixel region.(16) The spatial light modulator according to any one of (1) to (13) above, wherein the measuring element is arranged in one or more places in the slit portion of an effective pixel region having a slit portion. (17) The spatial light modulator according to any one of (1) to (16) above, wherein a common electrode having a structure divided into multiple regions is formed on the opposing substrate, and the measuring element is arranged in each of the regions, and the amount of phase modulation of light by the light modulation layer is measured in each of the regions.

[0107] This application claims priority based on Japanese Patent Application No. 2025-050203, filed with the Japan Patent Office on 25 March 2025, and all contents of that application are incorporated herein by reference.

[0108] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

1. A spatial light modulator comprising a plurality of pixels having an optical modulation layer that modulates the phase of incident light, and a measuring element that measures the amount of phase modulation of light by the optical modulation layer.

2. The spatial light modulator according to claim 1, further comprising a correction circuit for correcting the amount of phase modulation in each pixel based on the measured value of the measuring element.

3. The spatial light modulator according to claim 2, wherein the plurality of pixels have a common electrode provided in common to the plurality of pixels and a pixel electrode provided for each of the plurality of pixels, and the correction circuit corrects the amount of phase modulation in each of the pixels by correcting at least one of the voltage applied to the pixel electrode and the voltage applied to the common electrode.

4. The spatial light modulator according to claim 1, further comprising a counter substrate disposed on the light incident side and a pixel substrate disposed opposite to the counter substrate so as to sandwich the light modulation layer, wherein the measuring element is disposed within the pixel substrate and measures the light intensity of light that has passed through the light modulation layer.

5. The spatial light modulator according to claim 4, wherein the plurality of pixels include a first pixel and a second pixel, and the measuring element measures the amount of phase modulation by the optical modulation layer by measuring the light intensity after interfering a first light from the first pixel that has passed through the optical modulation layer with a second light from the second pixel that has passed through the optical modulation layer.

6. The spatial light modulator according to claim 5, further comprising an optical member disposed within the pixel substrate for focusing the first light and the second light toward the measuring element.

7. The spatial light modulator according to claim 5, wherein each of the plurality of pixels has a pixel electrode, the pixel electrode corresponding to the first pixel is provided with a first aperture through which the first light can pass, the pixel electrode corresponding to the second pixel is provided with a second aperture through which the second light can pass, and the measuring element collects the first light that has passed through the first aperture and the second light that has passed through the second aperture.

8. The spatial light modulator according to claim 5, wherein the measuring element is positioned at a location corresponding to the second pixel, and the optical modulation state in the first pixel is set to a low refractive index state, and the optical modulation state in the second pixel is set to a high refractive index state, thereby receiving a portion of the incident light to the first pixel and a portion of the incident light to the second pixel at the measuring element.

9. The spatial light modulator according to claim 5, wherein the measuring elements include a first measuring element positioned at a location corresponding to the first pixel and a second measuring element positioned at a location corresponding to the second pixel, and the amount of phase modulation of light by the light modulation layer is measured based on a first measurement value obtained by the first measuring element and a second measurement value obtained by the second measuring element.

10. The spatial light modulator according to claim 5, further comprising a light-shielding layer provided between the measuring element and the first pixel and the second pixel, at a position corresponding to the position between the first pixel and the second pixel, which blocks light passing between the two pixels, the first pixel and the second pixel.

11. The spatial light modulator according to claim 4, further comprising a first polarizer disposed between one of the plurality of pixels and the measuring element, wherein the measuring element measures the amount of phase modulation by the light modulation layer by measuring the light intensity of the light after modulation of the incident light to one of the plurality of pixels via the first polarizer.

12. The spatial light modulator according to claim 11, further comprising a waveplate positioned on the light incident side with respect to the light modulation layer at a position corresponding to one of the plurality of pixels.

13. The spatial light modulator according to claim 11, further comprising a second polarizing plate positioned on the light incident side with respect to the light modulation layer at a position corresponding to one of the plurality of pixels.

14. The spatial light modulator according to claim 1, wherein one or more measuring elements are arranged in a region inside the effective pixel region.

15. The spatial light modulator according to claim 1, wherein one or more measuring elements are arranged in a region outside the effective pixel region.

16. The spatial light modulator according to claim 1, wherein one or more measuring elements are arranged in the slit portion of an effective pixel region having a slit portion.

17. The spatial light modulator according to claim 4, wherein a common electrode having a structure divided into multiple regions is formed on the opposing substrate, the measuring element is arranged in each of the regions, and the amount of phase modulation of light by the light modulation layer is measured in each of the regions.

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