Light modulation device, light observation device and light irradiation device

Abstract

To provide a light modulation device, a light observation device and a light irradiation device which are able to achieve stable light modulation.SOLUTION: A light modulation device 21 comprises: an electro-optic crystal 22; a transparent electrode 23 provided on an input surface 22a of the electro-optic crystal 22 and transmitting input light; a gap buffer layer 24 provided between the transparent electrode 23 and the electro-optic crystal 22; and a reflection part 25 including a plurality of pixel electrodes 30 provided on a back surface 22b of the electro-optic crystal 22 and reflecting input light Lp toward the transparent electrode. A dielectric constant of the gap buffer layer 24 is a value between a dielectric constant of the transparent electrode 23 and that of the electro-optic crystal 22. The transparent electrode 23 includes a gap G sectioning the transparent electrode 23 into a plurality of electrode regions R facing at least one of the plurality of pixel electrodes 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a light modulation device, a light observation device, and a light irradiation device. [Background technology]

[0002] As an example of a technology related to an optical modulation device, there is a reflective spatial light modulator described in Patent Document 1. This reflective spatial light modulator includes an electro-optic crystal, an optical input / output unit having a first electrode arranged on one side of the electro-optic crystal and transmitting input light, a plurality of second electrodes arranged on the other side of the electro-optic crystal, a reflector that reflects the input light toward the optical input / output unit, a plurality of pixel electrodes corresponding to the plurality of second electrodes, and a drive circuit that inputs an electric signal to each of the plurality of pixel electrodes and applies an electric field between the first electrode and the second electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 213098 Summary of the Invention [Problem to be solved by the invention]

[0004] In the optical modulation device described above, since the relative dielectric constant of the electro-optic crystal is relatively high, it is important to efficiently apply an electric field in the thickness direction of the electro-optic crystal. If the electric field in the horizontal direction intersecting the thickness direction (hereinafter referred to as the "transverse electric field") spreads and the value of the transverse electric field becomes large, it is considered that it becomes difficult to obtain a stable optical modulation.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a light modulation device, a light observation device, and a light irradiation device that can realize stable light modulation. [Means for solving the problem]

[0006] An optical modulation device according to one aspect of the present disclosure is an optical modulation device that modulates input light and outputs it as modulated light, and includes an electro-optic crystal having an input surface to which the input light is input and a back surface opposite the input surface, a transparent electrode provided on the input surface side of the electro-optic crystal and transmitting the input light, a gap buffer layer provided between the transparent electrode and the electro-optic crystal, and a reflective section having a plurality of pixel electrodes arranged on the back surface side of the electro-optic crystal and reflecting the input light that reaches the back surface toward the transparent electrode, wherein the relative dielectric constant of the gap buffer layer is a value between the relative dielectric constant of the transparent electrode and the relative dielectric constant of the electro-optic crystal, and the transparent electrode has a gap that divides the transparent electrode into a plurality of electrode regions facing at least one of the plurality of pixel electrodes.

[0007] In this light modulation device, the transparent electrode is divided by gaps into a plurality of electrode regions facing at least one of the plurality of pixel electrodes. As a result, when an electric field is applied between the transparent electrode and the pixel electrode, the transverse electric field generated at the edge of the pixel electrode can be diffused in the transverse direction (arrangement direction of the pixel electrodes). In addition, in this light modulation device, the relative dielectric constant of the gap buffer layer is a value between the relative dielectric constant of the transparent electrode and the relative dielectric constant of the electro-optic crystal. By disposing the gap buffer layer in this way, the loss of the electric field between the transparent electrode and the electro-optic crystal can be suppressed, and the transverse electric field diffused by the formation of the gap can be smoothed, and the disturbance of the phase modulation pattern caused by the diffusion of the transverse electric field can be smoothed. Therefore, this light modulation device can realize stable light modulation.

[0008] The electrode regions may be rectangular, and the gaps may be provided to correspond to the sides of the electrode regions. With this configuration, the transverse electric field is further smoothed in a direction connecting the sides of the electrode regions.

[0009] The electrode regions may be rectangular, and the gaps may be provided to correspond to corners of the electrode regions, thereby further smoothing the transverse electric field in a direction connecting the corners of the electrode regions.

[0010] The electrode regions may be rectangular, and the gaps may be provided to correspond to both sides and corners of the electrode regions. With this configuration, the transverse electric field is further smoothed in both the direction connecting the sides of the electrode regions and the direction connecting the corners of the electrode regions.

[0011] The plurality of electrode regions may be connected to one another except for the gaps. By connecting the plurality of electrode regions to one another, a voltage can be applied uniformly between the plurality of pixel electrodes.

[0012] The relative dielectric constant of the electro-optic crystal is ε rc and the relative dielectric constant of the gap buffer layer is ε rf In this case, ε rc / 100<ε rf <ε rc / 5. By satisfying such a relationship of the relative dielectric constants, the loss of the electric field between the transparent electrode and the electro-optic crystal can be more effectively suppressed.

[0013] The gap may be an air gap, which allows the horizontal electric field generated at the edge of the pixel electrode to be diffused in the horizontal direction more reliably.

[0014] The gap may be made of an insulator. By making the gap an insulator, the horizontal electric field generated at the edge of the pixel electrode can be diffused in the horizontal direction more reliably. In addition, by surrounding a plurality of electrode regions with an insulator, a voltage can be applied uniformly between the plurality of pixel electrodes.

[0015] The light modulation device may include a drive substrate having a plurality of drive electrodes electrically connected to the plurality of pixel electrodes, a first power supply electrically connected to the transparent electrodes, and a second power supply electrically connected to the drive substrate. By using two power supplies on the transparent electrode side and the drive substrate side, it becomes possible to apply a voltage to the transparent electrodes that does not depend on the withstand voltage and control method of the drive substrate. This improves the degree of freedom of the modulation pattern for the input light.

[0016] An optical observation device according to one aspect of the present disclosure includes a light source that outputs input light, the optical modulation device, an optical system that guides the modulated light output from the optical modulation device to a sample, and a detector that detects light from the sample. Also, an optical irradiation device according to one aspect of the present disclosure includes a light source that outputs input light, the optical modulation device, and an optical system that guides the modulated light output from the optical modulation device to a sample.

[0017] In the light observation device and the light irradiation device, in the light modulation device, the transparent electrode is divided into a plurality of electrode regions by gaps, which face at least one of the plurality of pixel electrodes. As a result, when an electric field is applied between the transparent electrode and the pixel electrode, the transverse electric field generated at the edge of the pixel electrode can be diffused in the transverse direction (arrangement direction of the pixel electrodes). In addition, in the light modulation device, the relative dielectric constant of the gap buffer layer is a value between the relative dielectric constant of the transparent electrode and the relative dielectric constant of the electro-optic crystal. By disposing the gap buffer layer in this way, the loss of the electric field between the transparent electrode and the electro-optic crystal can be suppressed, and the transverse electric field diffused by the formation of the gap can be smoothed, and the disturbance of the phase modulation pattern caused by the diffusion of the transverse electric field can be smoothed. Therefore, in the light observation device and the light irradiation device, stable light modulation can be realized. Effect of the Invention

[0018] According to the present disclosure, stable optical modulation can be achieved. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of an optical observation device according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a schematic diagram illustrating a configuration of a light irradiation device according to an embodiment of the present disclosure. [Diagram 3] 1 is a schematic cross-sectional view illustrating a configuration of an optical modulation device according to an embodiment of the present disclosure. [Figure 4] 1A is a diagram showing the relationship between the crystal axis, the light propagation direction, and the electric field in retardation modulation, and FIG. 1B is a diagram showing each axis in a plane. [Diagram 5]FIG. 2A is a plan view showing a pixel electrode, and FIG. 2B is a plan view showing a driving electrode. [Figure 6] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 7] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 8] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 9] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 10] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 11] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 12] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 13] FIG. 2 is a schematic plan view showing an example of patterning of a transparent electrode. [Figure 14] 5A to 5C are schematic diagrams illustrating the effects of a gap buffer layer and a gap. [Figure 15] 13 is a schematic cross-sectional view showing a configuration of an optical modulation device according to a modified example. FIG. [Figure 16] FIG. 11 is a schematic plan view showing an example of gap patterning. [Figure 17] FIG. 11 is a schematic plan view showing an example of gap patterning. [Figure 18] FIG. 11 is a schematic plan view showing an example of gap patterning. [Figure 19] FIG. 1A is a diagram showing a calculation model for a phase modulation simulation, and FIG. 1B is a diagram showing each parameter used in the phase modulation simulation. [Figure 20] FIG. 13 is a diagram showing simulation results of the total number versus the position in the in-plane direction, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the embodiment. [Figure 21]1 is a diagram showing the primary distribution of the total number in the range of 60≦X<100, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the Example. [Figure 22] FIG. 13 is a diagram showing the primary distribution of the total number in the range of 100≦X≦150, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the Example. [Figure 23] FIG. 1 shows the average value of the total number for 60≦X<100, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the Example. [Figure 24] FIG. 1 shows the average value of the total number in the range of 100≦X≦150, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the Example. [Diagram 25] 5A to 5C are diagrams showing simulation results of the amount of phase modulation, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the embodiment. [Figure 26] 1 is a graph showing calculation results of modulation figure of merit in Comparative Examples 1 and 2 and an example. [Figure 27] 10 is a graph showing the results of reducing power consumption in an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, preferred embodiments of a light modulation device, a light observation device, and a light irradiation device according to one aspect of the present disclosure will be described in detail with reference to the drawings.

[0021] Fig. 1 is a schematic diagram showing a configuration of an optical observation device according to an embodiment of the present disclosure. The optical observation device 1 shown in Fig. 1 is configured as, for example, a fluorescence microscope that captures a fluorescent image of a sample S. The optical observation device 1 acquires an image of the sample S by irradiating an inspection light Ld onto a surface of the sample S and capturing light (such as fluorescence or reflected light) from the sample S in response to the irradiation of the inspection light Ld as observation light Lf.

[0022] Examples of the sample S include cells and biological samples containing fluorescent substances such as fluorescent dyes and fluorescent proteins. The sample S may be a semiconductor device or a film. The sample S emits observation light Lf such as fluorescence when irradiated with light in a predetermined wavelength range (excitation light or illumination light). The sample S may be accommodated in a holder that is transparent to the inspection light Ld and the observation light Lf. In this case, the holder may be held on a movable stage.

[0023] As shown in FIG. 1, the optical observation device 1 includes a light source 2, a collimator lens 3, a polarizing element 4, a polarizing beam splitter 5, an optical modulator 21, a first optical system 6, a beam splitter 7, an objective lens 8, a second optical system 9, a detector 10, and a control unit C.

[0024] The light source 2 outputs light including a wavelength that excites the sample S as the inspection light Ld. The inspection light Ld may be either coherent light or incoherent light. Examples of the light source that outputs coherent light include a laser diode (LD). Examples of the light source that outputs incoherent light include a light emitting diode (LED), a super luminescent diode (SLD), and a lamp light source.

[0025] The collimator lens 3 collimates the inspection light Ld output from the light source 2. The polarizing element 4 selectively transmits the inspection light Ld depending on the polarization component. The polarizing element 4 is, for example, a polarizing filter. Here, the polarizing element 4 transmits the S-wave component of the inspection light Ld. The polarizing beam splitter 5 reflects the inspection light Ld that has transmitted through the polarizing element 4 toward the light modulation device 21.

[0026] The light modulation device 21 is a spatial light modulator that modulates the phase or phase difference (retardation) of the inspection light Ld. In this embodiment, the light modulation device 21 is configured as a reflective spatial light modulator. The light modulation device 21 modulates the inspection light Ld and outputs modulated light Lm. The modulated light Lm output from the light modulation device 21 passes through the polarizing beam splitter 5 and is guided to the first optical system 6.

[0027] The light modulation device 21 is electrically connected to the control unit C, and constitutes a spatial light modulation unit. The operation of the light modulation device 21 is controlled by the control unit C. The light modulation device 21 performs the following operations in the light observation device 1: limiting the position of the irradiation spot of the inspection light Ld (modulated light Lm) irradiated onto the sample S, moving the position, simultaneously forming a plurality of irradiation spots, and controlling the phase.

[0028] The first optical system 6 optically couples the light modulation device 21 and the objective lens 8. The first optical system 6 includes, for example, a condenser lens. The first optical system 6 condenses the modulated light Lm output from the light modulation device 21 at the pupil position of the objective lens 8.

[0029] The beam splitter 7 is an optical element that separates the modulated light Lm and the observation light Lf. The beam splitter 7 may be a polarizing beam splitter or a dichroic mirror. The beam splitter 7 is configured to transmit, for example, the modulated light Lm, which is an excitation wavelength, and reflect the observation light Lf, which is a fluorescence wavelength. Depending on the configuration of the optical systems before and after the beam splitter 7 (for example, the first optical system 6 and the second optical system 9), or the type of microscope to which the optical observation device 1 is applied, the beam splitter 7 may be configured to reflect the modulated light Lm and transmit the observation light Lf.

[0030] The objective lens 8 collects the modulated light Lm and irradiates the sample S with it, and also guides the observation light Lf from the sample S in response to the irradiation of the modulated light Lm to the detector 10 in cooperation with the beam splitter 7. The objective lens 8 may be configured to be movable along the optical axes of the modulated light Lm and the observation light Lf by a driving element such as a piezoelectric actuator or a stepping motor. In this case, it becomes possible to arbitrarily adjust the collecting position of the modulated light Lm and the focal position of the observation light Lf.

[0031] The second optical system 9 optically couples the objective lens 8 and the detector 10. The second optical system 9 includes, for example, an imaging lens. The second optical system 9 forms an image of the observation light Lf from the objective lens 8 on the light receiving surface of the detector 10.

[0032] The detector 10 is a device that detects the observation light Lf. The detector 10 is configured with an image sensor such as a CCD image sensor or a CMOS image sensor. An image of the observation light Lf formed on the light receiving surface by the second optical system 9 is captured.

[0033] The control unit C is physically a computer system equipped with a storage device such as a RAM or a ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, etc. As the computer, for example, a personal computer, a cloud server, or a smart device (smartphone, tablet terminal, etc.) can be used. The control unit C causes the computer to execute a program for controlling the operation of the light source 2, the objective lens 8, the detector 10, etc. in the light observation device 1, or a program for controlling the phase modulation amount or the phase difference (retardation) modulation amount in the light modulation device 21, thereby performing the desired control.

[0034] Fig. 2 is a schematic diagram showing the configuration of a light irradiation device according to an embodiment of the present disclosure. The light irradiation device 11 is the same as the configuration of the light observation device 1 shown in Fig. 1 except for the beam splitter 7, the objective lens 8, the second optical system 9, and the detector 10. That is, the light irradiation device 11 is composed of a light source 2, a collimator lens 3, a polarizing element 4, a polarizing beam splitter 5, a light modulation device 21, a first optical system 6, and a control unit C.

[0035] In the light irradiation device 11, the modulated light Lm output from the light modulation device 21 passes through the polarizing beam splitter 5 and the first optical system 6, and is then irradiated onto the sample S. The light modulation device 21 performs operations such as limiting the position of the irradiation spot of the inspection light Ld (modulated light Lm) irradiated onto the sample S in the light irradiation device 11, moving the position, simultaneously forming a plurality of irradiation spots, and controlling the phase.

[0036] Next, the above-described optical modulation device 21 will be described in more detail.

[0037] FIG. 3 is a schematic cross-sectional view showing the configuration of an optical modulation device according to an embodiment of the present disclosure. The optical modulation device 21 shown in FIG. 3 is a device that modulates the input light Lp and outputs it as modulated light Lm. Here, a reflective spatial light modulator is exemplified. The input light Lp is the inspection light Ld in the above-described optical observation device 1 and optical irradiation device 11. As shown in FIG. 3, the optical modulation device 21 includes an electro-optic crystal 22, a transparent electrode 23, a gap buffer layer 24, a reflection portion 25, a drive substrate 26, a first power source 27, and a second power source 28.

[0038] The electro-optic crystal 22 has an input surface 22a into which the input light Lp is input and a back surface 22b opposite to the input surface 22a. The electro-optic crystal 22 has, for example, a perovskite-type crystal structure and changes the refractive index of the electro-optic crystal 22 based on an electro-optic effect such as the Pockels effect or the Kerr effect. The electro-optic crystal 22 having a perovskite-type crystal structure is an isotropic crystal belonging to the cubic point group m3m and has a relative permittivity of 1000 or more. The relative permittivity of the electro-optic crystal 22 can take a value of, for example, about 1000 to 20000.

[0039] Examples of such electro-optic crystals 22 include KTa 1-x Nb x O3 (0 ≦ x ≦ 1) crystal (KTN crystal), K 1-y Li y Ta 1-x Nb x O3 (0 ≦ x ≦ 1, 0 < y < 1) crystal, PLZT crystal, etc. Specifically, BaTiO3, or K3Pb3(Zn2Nb7)O 27 , K(Ta 0.65 Nb 0.35 )P3, Pb3MgNb2O9, Pb3NiNb2O9, etc. are exemplified.

[0040] In this embodiment, a KTN crystal is used as the electro-optic crystal 22. Since the KTN crystal is a cubic m3m point group, there is no Pockels effect, and phase modulation based on the Kerr effect is performed. Phase modulation can be performed by inputting light parallel or perpendicular to the crystal axis of the electro-optic crystal 22 and applying an electric field in the same direction. Retardation modulation can be performed by rotating the other two axes to any angle other than 0° and 90° around any crystal axis.

[0041] FIG. 4(a) is a diagram showing the relationship between the crystal axis, the light traveling direction, and the electric field in retardation modulation. FIG. 4(b) is a diagram showing each axis in a plane. Here, a case where the crystal is rotated at an angle of 45° is illustrated. When the axes X2 and X3 are rotated 45° around the axis X1 and new axes X1, X2', and X3' are defined, retardation modulation can be performed by inputting light into the electro-optic crystal 22 parallel or perpendicular to these axes X1, X2', and X3'. In the examples of FIG. 4(a) and FIG. 4(b), the electric field application direction 1102 is set parallel to the propagation direction 1101 of the input light in the crystal 1104. In this case, the Kerr coefficients used to modulate the input light Lp are g11, g12, and g44.

[0042] The dielectric constant of the KTN crystal is easily affected by temperature. For example, the dielectric constant is highest at about 20,000 around -5°C, and decreases to about 5,000 around 20°C, which is normal temperature. In this embodiment, as shown in FIG. 3, the optical modulator 21 has a temperature control element 29. The temperature control element 29 is formed of, for example, a Peltier element. The temperature control element 29 keeps the temperature of the electro-optic crystal 22 in operation at about -5°C.

[0043] The transparent electrode 23 is provided on the input surface 22a side of the electro-optic crystal 22. The transparent electrode 23 is made of, for example, ITO (indium tin oxide) and has transparency to the input light Lp and the modulated light Lm. The input light Lp passes through the transparent electrode 23 and is input to the electro-optic crystal 22, and the modulated light Lm modulated by the electro-optic crystal 22 is output to the outside of the light modulation device 21 via the transparent electrode 23.

[0044] The gap buffer layer 24 is a layer that suppresses the spread of the transverse electric field caused by the gap G. The gap buffer layer 24 is provided between the transparent electrode 23 and the electro-optic crystal 22. The gap buffer layer 24 is transparent to the input light Lp and the modulated light Lm. Examples of the material of the gap buffer layer 24 include KTN, KTaO3, and KNbO3. The polycrystalline or amorphous gap buffer layer 24 can be formed by various film formation methods such as vacuum deposition, sputtering, pulsed laser deposition, atomic layer deposition, and spin coating. The gap buffer layer 24 may also be formed by material modification using ion implantation or plasma. In this case, examples of ion species used in the gap buffer layer 24 include B, N, C, F, Al, P, Li, Na, K, and Mg.

[0045] The relative dielectric constant of the gap buffer layer 24 is a value between the relative dielectric constant of the transparent electrode 23 and the relative dielectric constant of the electro-optic crystal 22. That is, when the relative dielectric constant of the transparent electrode 23 is ε rtcо and the relative dielectric constant of the electro-optic crystal 22 is ε rc and the relative dielectric constant of the gap buffer layer 24 is ε rf In this case, the relative dielectric constant ε rf is ε rtcо <ε rf <ε rc Meet the following.

[0046] In this embodiment, the relative dielectric constant of the electro-optic crystal 22 is ε rc and the relative dielectric constant of the gap buffer layer 24 is ε rf In this case, the relative dielectric constant ε rf is ε rc / 100<ε rf <ε rc / 5. As an example, KTN crystal has a relative dielectric constant of about several tens of thousands in the state of single crystal bulk, but in the state of a thin film, the relative dielectric constant is reduced by about 1 / 10 to 1 / 100 compared to the state of the single crystal bulk. Therefore, for example, by forming electro-optic crystal 22 from a single crystal bulk of KTN crystal and forming gap buffer layer 24 from a thin film of KTN crystal, it is possible to easily satisfy the above relationship of relative dielectric constants.

[0047] The reflecting section 25 reflects the input light Lp that has reached the rear surface 22b of the electro-optic crystal 22 toward the transparent electrode 23. The reflecting section 25 has a plurality of pixel electrodes 30 arranged on the rear surface 22b side of the electro-optic crystal 22. The pixel electrodes 30 are metal electrodes made of, for example, aluminum. The pixel electrodes 30 can be formed by, for example, metal deposition using a mask pattern. In the reflecting section 25, as shown in, for example, FIG. 5(a), the pixel electrodes 30, which are rectangular (square) in plan view, are arranged in a matrix. In the example of FIG. 5(a), for convenience of explanation, the pixel electrodes 30 are arranged in a 4×4 pattern, but the number of pixel electrodes 30 arranged is arbitrary.

[0048] The width dimension of the pixel electrode 30 (here, the length of one side) is, for example, approximately the same as the thickness of the electro-optic crystal 22. If the width dimension of the pixel electrode 30 is excessive relative to the thickness of the electro-optic crystal 22, it is considered that crosstalk of electrical signals between adjacent pixel electrodes 30, 30 will increase. Therefore, by making the width dimension of the pixel electrode 30 approximately the same as the thickness of the electro-optic crystal 22, crosstalk of electrical signals between adjacent pixel electrodes 30, 30 can be suppressed.

[0049] The driving substrate 26 applies an electric field between the transparent electrode 23 and the pixel electrodes 30. The driving substrate 26 is a so-called CMOS substrate. The driving substrate 26 may be fixed to an organic substrate such as a glass epoxy (epoxy resin with a glass fiber sheet as a core material) substrate, or a ceramic substrate. The driving substrate 26 has a plurality of driving electrodes 31 electrically connected to the plurality of pixel electrodes 30, respectively.

[0050] On the drive substrate 26, as shown in Fig. 5(b), for example, the drive electrodes 31, which are rectangular (square) in plan view, are arranged in a matrix at the same arrangement pitch as the pixel electrodes 30. In the example of Fig. 5(b), for convenience of explanation, the drive electrodes 31 are arranged in a 4 x 4 pattern, but the number of drive electrodes 31 is set according to the number of pixel electrodes 30. Each drive electrode 31 is provided with a drive switch 32. The application of a voltage to each pixel electrode 30 is controlled by the operation of the switch 32.

[0051] 3, the drive electrodes 31 and the pixel electrodes 30 are disposed opposite each other in the thickness direction of the electro-optic crystal 22, and are individually electrically connected by bumps 33. The bumps 33 are made of, for example, gold or solder. In the region between the electro-optic crystal 22 and the drive substrate 26, there may be a gap between the adjacent pixel electrodes 30, 30 and between the adjacent bumps 33, 33, or an insulator may be disposed therebetween.

[0052] The first power supply 27 and the second power supply 28 are power supplies for applying an electric field between the transparent electrode 23 and the pixel electrode 30. The first power supply 27 is electrically connected to the transparent electrode 23 and applies a voltage to the transparent electrode 23. The second power supply 28 is electrically connected to the drive substrate 26 and applies a voltage to the pixel electrode 30 via the drive electrode 31. The voltage of the transparent electrode 23 is V com and the voltage of the pixel electrode 30 is V px For example, when modulating, V com ≧2×V px A voltage is applied to the transparent electrode 23 and the pixel electrode 30 so as to satisfy the following:

[0053] In this embodiment, as described above, the multiple drive electrodes 31 and the multiple pixel electrodes 30 are individually electrically connected by the bumps 33. Therefore, an electric field can be applied to each of the multiple pixel electrodes 30 individually between the transparent electrode 23 and the pixel electrodes 30. This suppresses crosstalk of electrical signals between the pixel electrodes, and contributes to improving modulation accuracy.

[0054] In the light modulation device 21 as described above, a voltage is applied to the transparent electrode 23 and the pixel electrode 30 by the first power supply 27 and the second power supply 28, respectively, and the refractive index of the electro-optic crystal 22 changes in response to the electric field generated by the application of the voltage. By presenting a desired modulation pattern to the multiple pixel electrodes 30, the input light Lp passing through the electro-optic crystal 22 is phase-modulated in response to the change in the refractive index. The input light Lp is reflected by the pixel electrode 30, passes through the electro-optic crystal 22, and is again phase-modulated, and is output to the outside as modulated light Lm.

[0055] Next, the configuration of the transparent electrode 23 will be described in more detail.

[0056] In the light modulation device 21, the transparent electrode 23 has gaps G that divide the transparent electrode 23 into a plurality of electrode regions R facing at least one of the plurality of pixel electrodes 30. In this embodiment, the gaps G are formed by voids 34, and at the positions of the gaps G, the gap buffer layer 24 is exposed from the transparent electrode 23.

[0057] The gaps G are formed in positions between the pixel electrodes 30 arranged in a matrix and at positions that are the outer edges of the areas where the pixel electrodes 30 are arranged in a plan view. A part of the gaps G may overlap an edge of the pixel electrodes 30 in a plan view. The multiple electrode regions R are rectangular. The multiple electrode regions R are separated from each other at the gaps G and connected to each other in areas other than the gaps G.

[0058] For patterning the transparent electrode 23 including the gap G, for example, etching, lift-off, mask deposition, etc. can be used. Examples of etching include dry etching such as plasma etching or reactive ion etching, and wet etching such as dip etching or spin etching. Examples of lift-off include a peeling liquid immersion method or laser lift-off. Examples of mask deposition include a method using a metal mask.

[0059] 6 to 13 are schematic plan views showing an example of patterning of a transparent electrode. In the examples of FIGS. 6 and 7, the electrode regions R are divided into rectangular (square) shapes so as to correspond one-to-one to the pixel electrodes 30 arranged in a matrix. In the example of FIG. 6, the gaps G are provided so as to correspond to the respective sides of the electrode regions R. In the adjacent electrode regions R, R, the sides are separated by the gaps G, and the corners are connected to each other. The gaps G are also provided in the portion corresponding to the outer edge of the transparent electrode 23 so as to correspond to the respective sides of the electrode regions R. In the portion corresponding to the outer edge of the transparent electrode 23, the gaps G corresponding to the sides may extend to the corners, and the gaps G, G of the adjacent electrode regions R, R may be connected to each other.

[0060] 7, the gaps G are provided so as to correspond to the respective corners of the multiple electrode regions R. In adjacent electrode regions R, R, the corners are separated by the gaps G, and the sides are connected to each other. The gaps G are also provided in the portion corresponding to the outer edge of the transparent electrode 23 so as to correspond to the respective corners of the multiple electrode regions R. In the portion corresponding to the outer edge of the transparent electrode 23, the gaps G corresponding to the corners may extend to the sides, and the gaps G, G of adjacent electrode regions R, R may be connected to each other.

[0061] In the examples of Figs. 8 to 13, the electrode regions R are divided into rectangular shapes (square or rectangular shapes) to correspond to the pixel electrodes 30. In the example of Fig. 8, the electrode regions R are divided into rectangular shapes to correspond to 1 x 2 pixel electrodes 30. In adjacent electrode regions R, R, the sides are separated by a gap G, and the corners are connected to each other. In the center of the side that is the long side of the electrode region R, the gap G is separated in the extension direction of the side. The gap G is also provided in the part corresponding to the outer edge of the transparent electrode 23 so as to correspond to each side of the electrode regions R. In the part corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the side may extend to the corner, and the gaps G, G of adjacent electrode regions R, R may be connected to each other.

[0062] In the example of FIG. 9, the multiple electrode regions R are divided into squares corresponding to the 2×2 pixel electrodes 30. In adjacent electrode regions R, R, the sides are separated by gaps G, and the corners are connected to each other. In the center of the sides, the gaps G are separated in the extension direction of the sides. The gaps G are also provided in the parts corresponding to the outer edges of the transparent electrode 23 so as to correspond to each side of the multiple electrode regions R. In the parts corresponding to the outer edges of the transparent electrode 23, the gaps G corresponding to the sides may extend to the corners, and the gaps G of adjacent electrode regions R may be connected to each other.

[0063] 10, the multiple electrode regions R are divided into rectangular shapes corresponding to the 1×2 pixel electrodes 30. In adjacent electrode regions R, R, the corners are separated by gaps G, and the sides are connected to each other. Gaps G are also provided in the portion corresponding to the outer edge of the transparent electrode 23 so as to correspond to each corner of the multiple electrode regions R. In the portion corresponding to the outer edge of the transparent electrode 23, the gaps G corresponding to the corners may extend to the sides, and the gaps G of adjacent electrode regions R, R may be connected to each other.

[0064] 11, the multiple electrode regions R are divided into squares corresponding to the 2×2 pixel electrodes 30. In adjacent electrode regions R, R, the corners are separated by gaps G, and the sides are connected to each other. Gaps G are also provided in the portion corresponding to the outer edge of the transparent electrode 23 so as to correspond to each corner of the multiple electrode regions R. In the portion corresponding to the outer edge of the transparent electrode 23, the gaps G corresponding to the corners may extend to the sides, and the gaps G of adjacent electrode regions R may be connected to each other.

[0065] 12 and 13, the gaps G are provided to correspond to both the sides and corners of the electrode regions R. In the example of FIG. 12, the electrode regions R are divided into rectangular shapes to correspond to the 1×2 pixel electrodes 30. In adjacent electrode regions R, R, the corners and sides are separated by gaps G. Between the gaps G at the corners and the gaps G at the sides, the gaps G are spaced apart, and the adjacent electrode regions R, R are connected at the spaced apart portions. In the portion corresponding to the outer edge of the transparent electrode 23, the gaps G corresponding to the corners and the gaps G corresponding to the sides may be connected.

[0066] 13, the multiple electrode regions R are divided into squares to correspond to the 2×2 pixel electrodes 30. In adjacent electrode regions R, R, the corners and sides are separated by gaps G. Between the gaps G at the corners and the gaps G at the sides, the gaps G are spaced apart, and the adjacent electrode regions R, R are connected at the spaced apart portions. In the portion corresponding to the outer edge of the transparent electrode 23, the gaps G corresponding to the corners and the gaps G corresponding to the sides may be connected.

[0067] 14 is a schematic diagram for explaining the action and effect of the gap buffer layer and the gap. In the optical modulation device as described above, since the relative dielectric constant of the electro-optic crystal is relatively high (in this embodiment, it is about 1000 to 20000), it is important to efficiently apply an electric field in the thickness direction of the electro-optic crystal. If the electric field in the horizontal direction intersecting the thickness direction (hereinafter referred to as the "transverse electric field") spreads and the value of the transverse electric field becomes large, it is considered that it becomes difficult to obtain stability of the optical modulation.

[0068] As shown in FIG. 14, in the comparative example without the gap buffer layer and the gap, a voltage V px When a potential difference occurs between adjacent pixel electrodes, the amount of phase modulation may be disturbed in a region R1 corresponding to the edge of the pixel electrode. pxHowever, it is difficult to actually control the voltage applied to the electro-optic crystal, making it difficult to obtain stable optical modulation.

[0069] In the comparative example, even in region R2 corresponding to the center of the pixel electrode, the phase modulation amount is not flat, and a portion having a curvature may occur. Also, in region R3, which is outside the edge of the pixel electrode, the value of the lateral electric field becomes relatively high, and it is considered that the contrast between the phase modulation amount in region R2 and the phase modulation amount in region R3 decreases.

[0070] In contrast, in the light modulation device 21, the transparent electrode 23 is divided by the gap G into a plurality of electrode regions R facing at least one of the plurality of pixel electrodes 30. In this case, when a voltage is applied between the transparent electrode 23 and the pixel electrode 30, a lateral electric field smaller than the electric field generated in the pixel electrode 30 is generated between the transparent electrode 23 and the gap G. Therefore, it is possible to perform electric field emphasis in the region R1 corresponding to the edge of the pixel electrode 30, and the lateral electric field generated at the edge of the pixel electrode 30 can be diffused in the lateral direction (arrangement direction of the pixel electrodes 30). Therefore, as shown in FIG. 14, it is possible to eliminate the disturbance of the phase modulation amount in the region R1 corresponding to the edge of the pixel electrode, and the phase modulation amount is also flat in the region R2 corresponding to the center of the pixel electrode 30.

[0071] In addition, in the light modulation device 21, the relative dielectric constant of the gap buffer layer 24 is a value between the relative dielectric constant of the transparent electrode 23 and the relative dielectric constant of the electro-optic crystal 22. By disposing the gap buffer layer 24 in this manner, it is possible to suppress the loss of the electric field between the transparent electrode 23 and the electro-optic crystal 22, and to smooth the lateral electric field diffused by the formation of the gap G. This also contributes to the elimination of the disturbance of the phase modulation amount in the region R1 corresponding to the edge of the pixel electrode, and by reducing the value of the lateral electric field in the region R3 that is outside the edge of the pixel electrode, the contrast between the phase modulation amount in the region R2 and the phase modulation amount in the region R3 is improved. Therefore, the light modulation device 21 can realize stable light modulation.

[0072] In addition, by disposing the gap buffer layer 24 between the transparent electrode 23 and the electro-optic crystal 22, charges from the transparent electrode 23 are trapped in the gap buffer layer 24, which also has the effect of suppressing unexpected charge movement. This makes it possible to realize more stable light modulation, and is also expected to have the effect of suppressing charge injection.

[0073] In the present embodiment, the plurality of electrode regions R are rectangular, and the gaps G are provided to correspond to the sides of the plurality of electrode regions R. According to such a configuration, the transverse electric field is further smoothed in the direction connecting the sides of the plurality of electrode regions R.

[0074] In the present embodiment, the plurality of electrode regions R are rectangular, and the gaps G are provided to correspond to corners of the plurality of electrode regions R. According to such a configuration, the transverse electric field is further smoothed in the direction connecting the corners of the plurality of electrode regions R.

[0075] In this embodiment, the plurality of electrode regions R are rectangular, and the gaps G are provided to correspond to both the sides and the corners of the plurality of electrode regions R. According to this configuration, the transverse electric field is further smoothed in both the direction connecting the sides of the plurality of electrode regions R and the direction connecting the corners.

[0076] In this embodiment, the multiple electrode regions R are connected to one another except for the gaps G. By connecting the multiple electrode regions R to one another, a voltage can be applied between the multiple pixel electrodes 30 uniformly.

[0077] In this embodiment, the relative dielectric constant of the electro-optic crystal 22 is ε rc and the relative dielectric constant of the gap buffer layer 24 is ε rf In this case, ε rc / 100<ε rf <ε rc / 5. By satisfying such a relationship of the relative dielectric constants, the loss of the electric field between transparent electrode 23 and electro-optic crystal 22 can be suppressed more effectively.

[0078] In this embodiment, the gap G is formed by an air gap 34. By forming the gap G as an air gap, the lateral electric field generated at the edge of the pixel electrode 30 can be diffused in the lateral direction more reliably.

[0079] In this embodiment, the light modulation device 21 includes a drive substrate 26 having a plurality of drive electrodes 31 electrically connected to the plurality of pixel electrodes 30, a first power supply 27 electrically connected to the transparent electrode 23, and a second power supply 28 electrically connected to the drive substrate 26. By using two power supplies on the transparent electrode 23 side and the drive substrate 26 side, it becomes possible to apply a voltage to the transparent electrode 23 that does not depend on the withstand voltage and control method of the drive substrate 26. This improves the degree of freedom of the modulation pattern for the input light Lp.

[0080] Fig. 15 is a schematic cross-sectional view showing the configuration of an optical modulation device according to a modified example. As shown in Fig. 15, an optical modulation device 41 according to the modified example differs from the above-described optical modulation device 21 in that the gap G is formed of an insulator 44.

[0081] The insulator 44 is preferably transparent to the input light Lp and the modulated light Lm. Examples of materials for forming the insulator 44 include SiO2, SiN, and hydrogen silsesquioxane (HSQ). By forming the gap G as the insulator 44, the horizontal electric field generated at the edge of the pixel electrode 30 can be diffused in the horizontal direction more reliably. In addition, by surrounding the multiple electrode regions R with the insulator 44, a voltage can be applied uniformly between the multiple pixel electrodes 30.

[0082] In this embodiment, an insulator 44 is patterned on the gap buffer layer 24, and the transparent electrode 23 is provided on the entire surface of the gap buffer layer 24 so as to cover the insulator 44. That is, in this embodiment, the transparent electrode 23 is divided into a plurality of electrode regions R by the gaps G, which are the insulator 44, and the plurality of electrode regions R are connected to each other by the electrode portions of the transparent electrode 23 provided so as to cover the gaps G.

[0083] 16 to 18 are schematic plan views showing an example of gap patterning. For ease of explanation, the electrode portion of the transparent electrode 23 provided to cover the gap G is omitted in Figs. 16 to 18. In the example of Fig. 16, the multiple electrode regions R are divided into rectangular (square) shapes so as to correspond one-to-one to the pixel electrodes 30 arranged in a matrix. The gaps G, which are insulators 44, are provided in a lattice pattern between the multiple electrode regions R and in the portions corresponding to the outer edges of the transparent electrode 23.

[0084] In the example of Fig. 17, the multiple electrode regions R are divided into rectangular shapes to correspond to the 1 × 2 pixel electrodes 30. Gaps G, which are insulators 44, are provided in a lattice pattern between the multiple electrode regions R and in the portions corresponding to the outer edges of the transparent electrode 23. In the example of Fig. 18, the multiple electrode regions R are divided into square shapes to correspond to the 2 × 2 pixel electrodes 30. Gaps G, which are insulators 44, are provided in a lattice pattern between the multiple electrode regions R and in the portions corresponding to the outer edges of the transparent electrode 23.

[0085] When the gap G is formed by the insulator 44, it is not necessary to connect the plurality of electrode regions R to each other by the electrode portion of the transparent electrode 23 provided so as to cover the gap G, as in the above-described light modulation device 41. For example, in the patterning of the transparent electrode 23 shown in Figs. 6 to 13, the gap G formed by the void 34 may be replaced with the gap G formed by the insulator 44.

[0086] Next, a test for verifying the effect of the present disclosure will be described.

[0087] This test assumes a calculation model 101 shown in FIG. 19(a) and assumes a voltage V px In the calculation model 101 of the embodiment, the electro-optic crystal 122 is a KTN crystal, a gap buffer layer 124 and a transparent electrode 123 are set on the input surface of the electro-optic crystal 122, and a plurality of pixel electrodes 130 are set on the back surface of the electro-optic crystal. pxA gap G was set in the transparent electrode 123 corresponding to the position of the boundary with the pixel electrode 130 .

[0088] The parameters used in the phase modulation simulation are summarized in Fig. 19(b). Here, the wavelength of the input light is 632.8 nm, the thickness of the electro-optic crystal is 50 μm, the relative dielectric constant of the electro-optic crystal is 20000, the refractive index of the electro-optic crystal is 2.318, the Kerr coefficient g12 is -0.038, the thickness of the gap buffer layer is 0.5 μm, and the relative dielectric constant of the gap buffer layer is 2000.

[0089] A calculation model in which the gap buffer layer 124 and the gap G of the transparent electrode 123 were omitted from the calculation model 101 was used as a calculation model of Comparative Example 1. A calculation model in which the gap G was set in the transparent electrode 123 and the gap buffer layer 124 was omitted from the calculation model 101 was used as a calculation model of Comparative Example 2.

[0090] Fig. 20(a) is a diagram showing the simulation results of Comparative Example 1, and Fig. 20(b) is a diagram showing the simulation results of Comparative Example 2. Fig. 20(c) is a diagram showing the simulation results of the Example. In these figures, the horizontal axis represents the in-plane position X, and the vertical axis represents the total number. The total number is the total number of amplitudes of the electric field components of the input light input to the in-plane position X. As shown in Figs. 20(a) and 20(b), in Comparative Examples 1 and 2, the total number is not flat in the region corresponding to the center of the pixel electrode, and there is also a disturbance in the total number in the region corresponding to the edge of the pixel electrode.

[0091] On the other hand, as shown in Fig. 20(c), in the embodiment, the total number in the region corresponding to the center of the pixel electrode is flat, and the fluctuation in the total number in the region corresponding to the edge of the pixel electrode is also suppressed. It can also be seen that the contrast between the total number in the pixel electrode region and the total number in the region outside the edge of the pixel electrode is improved compared to Comparative Examples 1 and 2.

[0092] Based on the results of FIG. 20, in the range of 60≦X<100 (applied voltage V px21(a) to 21(c) are diagrams showing the first-order variance of the total number in the range of 60≦X<100, with (a) showing the results of Comparative Example 1, (b) showing the results of Comparative Example 2, and (c) showing the results of the Example. As shown in FIG. 21(a) to FIG. 21(c), it was confirmed that in the range of 60≦X<100, the first-order variance of the total number in the Example was smaller than in Comparative Examples 1 and 2. In Comparative Examples 1 and 2, when the applied voltage V px As the applied voltage V px Even when V becomes large, the first-order variance of the total number hardly changes, and px It is also kept below 0.002.

[0093] 22(a) to 22(c) are diagrams showing the primary dispersion of the total number in the range of 100≦X≦150, with (a) showing the results of Comparative Example 1, (b) showing the results of Comparative Example 2, and (c) showing the results of the Example. As shown in FIG. 22(a) to FIG. 22(c), it was confirmed that even in the range of 100≦X≦150, the primary dispersion of the total number in the Example was smaller than that in Comparative Examples 1 and 2. In Comparative Examples 1 and 2, the applied voltage V px As the applied voltage V px Even when V becomes large, the first-order variance of the total number hardly changes, and px is also kept to almost zero.

[0094] 23(a) to 23(c) are diagrams showing the average value of the total number when 60≦X<100, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the Example. As shown in FIG. 23(a) to FIG. 23(c), when 60≦X<100, in all of Comparative Examples 1 and 2 and the Example, the applied voltage V px As the value of V increases, the average number of electrons tends to decrease. px It can be seen that the average value of the total number is smaller in the embodiment than in the comparative examples 1 and 2.

[0095] 24(a) to 24(c) are diagrams showing the average value of the total number in the range of 100≦X≦150, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the Example. As shown in FIG. 24(a) and FIG. 24(b), in Comparative Examples 1 and 2, even though the applied voltage was 0V, V px The average value of the total number shows a similar tendency to that in the range of 60≦X<100 due to the influence of the part where the applied voltage V px , the average value of the total number is almost constant even when the number of pixels increases. Therefore, it was confirmed that the influence of the horizontal electric field of the adjacent pixels is reduced in the embodiment.

[0096] 25(a) to 25(c) are diagrams showing the results of a simulation of the amount of phase modulation, where (a) shows the results of Comparative Example 1, (b) shows the results of Comparative Example 2, and (c) shows the results of the Example. Here, the amount of phase modulation θ was determined as the difference between the average value of the total number when 100≦X≦150 and the average value of the total number when 60≦X<100. As shown in FIG. 25(a) to FIG. 25(c), in all of Comparative Examples 1 and 2 and the Example, the applied voltage V px As the applied voltage V increases, the phase modulation amount θ tends to increase. px It can be seen that the phase modulation amount θ is larger in the embodiment than in the first and second comparative examples.

[0097] From the above results, it has been confirmed that the configuration disclosed herein, in which gaps are provided in the transparent electrode to divide it into multiple electrode regions, and further, a gap buffer layer having a relative dielectric constant between that of the transparent electrode and the electro-optic crystal, contributes to realizing stable optical modulation in an optical modulation device.

[0098] 26 is a graph showing the calculation results of the modulation figure of merit in Comparative Examples 1 and 2 and the Example. This graph shows the modulation figure of merit when the voltage V com When V is fixed at 30V, the bias ratio V brIt shows the relationship with the phase modulation amount. The phase modulation amount is a value calculated as the difference between the average value of the total number in the range of 100 < X < 150 for the in-plane position X and the average value of the total number in the range of 60 ≤ X < 100 for the in-plane position X. Also, the bias ratio V br is a parameter calculated by ΔV px / V com . The modulation performance index α is a parameter calculated by θ / V Br when the phase modulation amount is θ, and it quantifies the efficiency of the phase modulation amount with respect to the applied voltage. In the calculation, V px is set to 0 V in the range of 100 < X < 150, and in other ranges, V br is set so that V pr is 0.5 or less. The phase modulation amount is calculated based on the difference in the average value between the range where V px is 0 V and other ranges respectively.

[0099] As shown in FIG. 26, in Comparative Example 1, the modulation performance index α was 0.733, and in Comparative Example 2, the modulation performance index α was 0.681. In contrast, in the example, the modulation performance index α was 1.255, and it was confirmed that the modulation performance index α was improved by the configuration of the present disclosure, and the efficiency of the phase modulation amount was achieved.

[0100] FIG. 27 is a graph showing the result of reducing the power consumption in the example. This graph shows the relationship between the phase modulation amount θ with respect to the applied voltage V com when the voltage V com of the transparent electrode is 30 V and when the voltage V px of the transparent electrode is 60 V in the example. As shown in FIG. 27, compared with the case where V com is 60 V, the phase modulation amount is larger when V com is 30 V for the same applied V px .

[0101] This result is the voltage V of the transparent electrode comIt is presumed that the reason is that when the voltage V of the transparent electrode becomes high, the phase modulation becomes more disturbed and the amount of phase modulation is dispersed in the horizontal direction. com It was suggested that by lowering , the disturbance of the phase modulation is reduced and the lateral dispersion of the phase modulation amount is suppressed, and as a result, the phase modulation amount can be secured more effectively.

[0102] The gist of the present disclosure is as follows: [1] to

[11] . [1] An optical modulation device that modulates input light and outputs it as modulated light, comprising: an electro-optic crystal having an input surface to which the input light is input and a back surface opposite the input surface; a transparent electrode provided on the input surface side of the electro-optic crystal and transmitting the input light; a gap buffer layer provided between the transparent electrode and the electro-optic crystal; and a reflective section having a plurality of pixel electrodes arranged on the back surface side of the electro-optic crystal and reflecting the input light that has reached the back surface toward the transparent electrode, wherein the relative dielectric constant of the gap buffer layer is a value between the relative dielectric constant of the transparent electrode and the relative dielectric constant of the electro-optic crystal, and the transparent electrode has a gap that divides the transparent electrode into a plurality of electrode regions facing at least one of the plurality of pixel electrodes. [2] The optical modulation device according to [1], wherein the plurality of electrode regions are rectangular, and the gap is provided to correspond to a side of the plurality of electrode regions. [3] The optical modulation device according to [1], wherein the plurality of electrode regions are rectangular, and the gaps are provided to correspond to corners of the plurality of electrode regions. [4] The optical modulation device according to [1], wherein the plurality of electrode regions are rectangular, and the gap is provided to correspond to both the sides and corners of the plurality of electrode regions. [5] The optical modulation device according to any one of [1] to [4], wherein the plurality of electrode regions are connected to each other except for the gap. [6] The relative dielectric constant of the electro-optic crystal is ε rc and the relative dielectric constant of the gap buffer layer is ε rf In this case, ε rc / 100<εrf <ε rc The optical modulation device according to any one of [1] to [5], which satisfies / 5. [7] The optical modulation device according to any one of [1] to [6], wherein the gap is constituted by an air gap. [8] The optical modulation device according to any one of [1] to [6], wherein the gap is made of an insulator. [9] An optical modulation device according to any one of [1] to [8], comprising: a drive substrate having a plurality of drive electrodes electrically connected to each of the plurality of pixel electrodes; a first power supply electrically connected to the transparent electrode; and a second power supply electrically connected to the drive substrate.

[10] An optical observation device comprising: a light source that outputs the input light; an optical modulation device according to any one of claims 1 to 9; an optical system that guides the modulated light output from the optical modulation device to a sample; and a detector that detects light from the sample.

[11] A light irradiation device comprising: a light source that outputs the input light; an optical modulator according to any one of claims 1 to 9; and an optical system that guides the modulated light output from the optical modulator to a sample. [Explanation of symbols]

[0103] 1...light observation device, 2...light source, 6...first optical system (optical system), 10...detector, 11...light irradiation device, 21, 41...light modulation device, 22...electro-optical crystal, 22a...input surface, 22b...rear surface, 23...transparent electrode, 24...gap buffer layer, 25...reflective portion, 26...driving substrate, 27...first power supply, 28...second power supply, 30...pixel electrode, 31...driving electrode, 34...gap, 44...insulator, Lp...input light, Lm...modulated light, G...gap, R...electrode region, S...sample.

Claims

1. An optical modulation device that modulates input light and outputs it as modulated light, an electro-optic crystal having an input surface to which the input light is input and a back surface opposite to the input surface; a transparent electrode provided on the input surface side of the electro-optic crystal and transmitting the input light; a gap buffer layer provided between the transparent electrode and the electro-optic crystal; a reflecting section having a plurality of pixel electrodes arranged on the back surface side of the electro-optic crystal, the reflecting section reflecting the input light that has reached the back surface toward the transparent electrode, the dielectric constant of the gap buffer layer is a value between the dielectric constant of the transparent electrode and the dielectric constant of the electro-optic crystal, The transparent electrode has gaps that divide the transparent electrode into a plurality of electrode regions facing at least one of the plurality of pixel electrodes.

2. The plurality of electrode regions are rectangular in shape, The optical modulation device according to claim 1 , wherein the gaps are provided to correspond to sides of the plurality of electrode regions.

3. The plurality of electrode regions are rectangular in shape, The optical modulation device according to claim 1 , wherein the gaps are provided so as to correspond to corners of the plurality of electrode regions.

4. The plurality of electrode regions are rectangular in shape, 2. The optical modulation device according to claim 1, wherein the gaps are provided so as to correspond to both sides and corners of the plurality of electrode regions.

5. The optical modulation device according to claim 1 , wherein the plurality of electrode regions are connected to each other except for the gap.

6. The relative dielectric constant of the electro-optic crystal is ε ｒｃ and the relative dielectric constant of the gap buffer layer is ε ｒｆ In this case, ε ｒｃ / 100<ε ｒｆ <ε ｒｃ 2. The optical modulation device according to claim 1, wherein the optical modulation device satisfies .DELTA..times ...

7. The optical modulation device according to claim 1 , wherein the gap is constituted by an air gap.

8. The optical modulation device according to claim 1 , wherein the gap is formed of an insulator.

9. a driving substrate having a plurality of driving electrodes electrically connected to the plurality of pixel electrodes, respectively; a first power source electrically connected to the transparent electrode; The light modulation device of claim 1 , further comprising: a second power supply electrically connected to the drive substrate.

10. a light source for outputting the input light; An optical modulator according to any one of claims 1 to 9; an optical system that guides modulated light output from the optical modulator to a sample; and a detector for detecting light from the sample.

11. a light source for outputting the input light; An optical modulator according to any one of claims 1 to 9; an optical system that guides the modulated light output from the optical modulator to a sample.

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