Optical modulation device, optical observation device and light irradiation device

Abstract

An optical modulation device 21 comprises: an electro-optic crystal 22; a transparent electrode 23, which is provided on the side of an input surface 22a of the electro-optic crystal 22 and transmits input light; a slit buffer layer 24, which is provided between the transparent electrode 23 and the electro-optic crystal 22; and a reflection unit 25 with a plurality of pixel electrodes 30, which are arranged on the side of a back surface 22b of the electro-optic crystal 22 and reflect the input light Lp towards the transparent electrode. The relative permittivity of the slit buffer layer 24 is a value between the relative permittivity of the transparent electrode 23 and the relative permittivity of the electro-optic crystal 22.The transparent electrode 23 has a gap G which divides the transparent electrode 23 into a plurality of electrode regions R which are oriented towards at least one of the plurality of pixel electrodes 30.

Description

Technical area

[0001] The present disclosure relates to an optical modulation device, an optical observation device and a light irradiation device. State of the art

[0002] As a technique relating to an optical modulation device, there is, for example, a reflective spatial light modulator described in patent literature 1. The reflective spatial light modulator comprises an electro-optic crystal, a light input / output unit arranged on one face of the electro-optic crystal and having a first electrode that transmits input light, a plurality of second electrodes arranged on the other face of the electro-optic crystal, a reflection unit that reflects the input light towards the light input / output unit, a plurality of pixel electrodes corresponding to the plurality of second electrodes, and a drive circuit that inputs an electrical signal into each of the plurality of pixel electrodes and applies an electric field between the first electrode and the second electrode. List of oppositions patent literature

[0003] Patent literature 1: WO 2017 / 213098 A Summary of the invention: Technical problem

[0004] In the optical modulation device described above, the relative permittivity of the electro-optic crystal is relatively high, which is why it is important to apply the electric field efficiently in the thickness direction of the electro-optic crystal. If an electric field propagates in a lateral direction that intersects the thickness direction (hereinafter referred to as the "lateral electric field") and the value of the lateral electric field increases, it is assumed that the stability of the light modulation will be difficult to achieve.

[0005] The present disclosure was made to solve the above-mentioned problems, and one objective of the present disclosure is to provide an optical modulation device, an optical observation device and a light irradiation device capable of achieving stable light modulation. Problem solving

[0006] An optical modulation device according to one aspect of the present disclosure is an optical modulation device that modulates input light and outputs the modulated input light as modulated light, the optical modulation device comprising: an electro-optic crystal with an input face at which the input light is introduced and a rear face opposite the input face; a transparent electrode provided on the side of an input face of the electro-optic crystal and transmitting input light; a gap buffer layer provided between the transparent electrode and the electro-optic crystal;and a reflection unit with a plurality of pixel electrodes arranged on one side of the back surface of the electro-optic crystal and reflecting the input light reaching the back surface towards the transparent electrode, wherein a relative permittivity of the slit buffer layer is a value between a relative permittivity of the transparent electrode and the relative permittivity of the electro-optic crystal, and the transparent electrode has a slit that divides the transparent electrode into a plurality of electrode regions facing at least one of the plurality of pixel electrodes.

[0007] In this optical modulation device, the transparent electrode is divided by the slit into a plurality of electrode regions, each facing at least one of the plurality of pixel electrodes. When an electric field is applied between the transparent electrode and the pixel electrode, a lateral electric field generated at the edge of the pixel electrode can undergo dispersion in the lateral direction (direction of arrangement of the pixel electrodes). In this optical modulation device, the relative permittivity of the slit buffer layer is a value that lies between the relative permittivity of the transparent electrode and the relative permittivity of the electro-optic crystal.By arranging the slit buffer layer, the loss of the electric field between the transparent electrode and the electro-optic crystal can be suppressed, the lateral electric field subjected to dispersion by the formation of the slit can be smoothed, and the disturbance of a phase modulation pattern caused by the dispersion of the lateral electric field can be smoothed. Therefore, stable light modulation can be achieved in this optical modulation device.

[0008] The plurality of electrode regions can have a rectangular shape, and the gap can be configured to correspond to a side segment of each of the plurality of electrode regions. According to such a configuration, the lateral electric field is further smoothed in the direction where the side segments of the plurality of electrode regions face each other.

[0009] The plurality of electrode regions can have a rectangular shape, and the gap can be positioned to correspond to a corner section of each of the plurality of electrode regions. According to such a configuration, the lateral electric field is further smoothed in the direction where the corner sections of the plurality of electrode regions face each other.

[0010] The plurality of electrode regions can have a rectangular shape, and the gap can be configured to correspond to both a side section and a corner section of each of the plurality of electrode regions. According to such a configuration, the lateral electric field is further smoothed both in the direction where the side sections of the plurality of electrode regions face each other and in the direction where the corner sections face each other.

[0011] The multitude of electrode regions can be interconnected at sections that eliminate the gap. Because the multitude of electrode regions are interconnected, a voltage can be applied uniformly across the multitude of pixel electrodes.

[0012] If the relative permittivity of the electro-optic crystal ε rc is and the relative permittivity of the gap buffer layer ε rf is, can ε rc / 100 < ε rf < ε rc / 5 must be satisfied. By satisfying such a relative permittivity relation, the loss of the electric field between the transparent electrode and the electro-optic crystal can be suppressed more effectively.

[0013] The gap can be formed by a cavity. By forming the gap as a cavity, the lateral electric field generated at the edge of the pixel electrode can undergo more reliable lateral dispersion.

[0014] The gap can be formed by an insulator. By forming the gap as an insulator, the lateral electric field generated at the edge of the pixel electrode can be more reliably dispersed laterally. Since the multitude of electrode areas are surrounded by the insulator, a voltage can be applied uniformly across the multitude of pixel electrodes.

[0015] The optical modulation device can further comprise: a drive substrate with a plurality of drive electrodes, each electrically connected to one 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. By using two power supply systems, one on the transparent electrode side and one on the drive substrate side, it is possible to apply a voltage to the transparent electrode that is independent of the dielectric strength of the drive substrate and the control method. This allows for an improvement in the degrees of freedom of the modulation pattern for the input light.

[0016] An optical observation device according to one aspect of the present disclosure comprises: a light source emitting the input light; the optical modulation device; an optical system directing the modulated light emitted by the optical modulation device to a sample; and a detector detecting light from the sample. A light irradiation device according to one aspect of the present disclosure comprises: a light source emitting the input light; the optical modulation device; and an optical system directing the modulated light emitted by the optical modulation device to a sample.

[0017] In the optical observation device and the light irradiation device, the transparent electrode is divided by the slit in the optical modulation device into a plurality of electrode regions, each facing at least one of the plurality of pixel electrodes. When an electric field is applied between the transparent electrode and the pixel electrode, a lateral electric field generated at the edge of the pixel electrode can undergo dispersion in a lateral direction (the orientation of the pixel electrodes). In this optical modulation device, the relative permittivity of the slit buffer layer is a value that lies between the relative permittivity of the transparent electrode and the relative permittivity of the electro-optic crystal.By arranging the slit buffer layer, the loss of the electric field between the transparent electrode and the electro-optic crystal can be suppressed, and the lateral electric field subjected to dispersion by the formation of the slit can be smoothed. This also smooths the disturbance of the phase modulation pattern caused by the lateral electric field dispersion. Therefore, stable light modulation can be achieved in the optical observation device and the light irradiation device. Advantageous effects of the invention

[0018] According to the present disclosure, stable light modulation can be achieved. Brief description of the drawings Fig. Figure 1 is a schematic view showing the configuration of an optical observation device according to an embodiment of the present disclosure. Fig. Figure 2 is a schematic view showing the configuration of a light irradiation device according to an embodiment of the present disclosure. Fig. Figure 3 is a schematic cross-sectional view showing the configuration of an optical modulation device according to an embodiment of the present disclosure. Fig. 4(a) is a view that represents a relationship between a crystal axis, a direction of light propagation and an electric field in a delay modulation, and Fig. 4(b) is a view that represents each axis in a planar manner. Fig. 5(a) is a top view showing a pixel electrode, and the Fig. 5(b) is a top view showing a control electrode. Fig. Figure 6 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 7 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 8 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 9 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 10 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 11 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 12 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 13 is a schematic top view showing an example of the structuring of a transparent electrode. Fig. Figure 14 is a schematic view illustrating the functions and effects of a gap buffer layer and a gap. Fig. Figure 15 is a schematic cross-sectional view showing the configuration of an optical modulation device according to a modification. Fig. Figure 16 is a schematic top view that provides an example of the structuring of a gap. Fig. Figure 17 is a schematic top view that provides an example of the structuring of a gap. Fig. Figure 18 is a schematic top view that provides an example of the structuring of a gap. Fig. 19(a) is a view that presents the computational model of the phase modulation simulation, and the Fig. Figure 19(b) is a view showing the individual parameters used for phase modulation simulation. Fig. Figures 20(a) to 20(c) are views showing the simulation results of the total numbers in relation to positions in the in-plane direction, where the Fig. 20(a) represents the result of comparison example 1, which Fig. 20(b) represents the result of comparison example 2 and the Fig. 20(c) represents the result of the example. Fig. Figures 21(a) to 21(c) are views representing the first-order dispersions of the totals in 60 ≤ X < 100, where the Fig. 21(a) represents the result of comparison example 1, which Fig. 21(b) represents the result of comparison example 2 and the Fig. 21(c) represents the result of the example. Fig. 22(a) to 22(c) are views representing the first-order dispersions of the totals in 100 ≤ X ≤ 150, where the Fig. 22(a) represents the result of comparison example 1, which Fig. 22(b) represents the result of comparison example 2 and the Fig. 22(c) represents the result of the example. Fig. Figures 23(a) to 23(c) are views representing the average values ​​of the totals in 60 ≤ X < 100, where the Fig. 23(a) represents the result of comparison example 1, which Fig. 23(b) represents the result of comparison example 2 and the Fig. 23(c) represents the result of the example. Fig. 24(a) to 24(c) are views representing the average values ​​of the totals in 100 ≤ X ≤ 150, where the Fig. 24(a) represents the result of comparison example 1, which Fig. 24(b) represents the result of comparison example 2 and the Fig. 24(c) represents the result of the example. Fig. Figures 25(a) to 25(c) are views that represent the simulation results of the phase modulation amounts, where the Fig. 25(a) represents the result of comparison example 1, which Fig. 25(b) represents the result of comparison example 2 and the Fig. 25(c) represents the result of the example. Fig. Figure 26 is a diagram that shows the calculation results of figures of modulation quality in comparison examples 1 and 2 and the example. Fig. Figure 27 is a diagram that illustrates the result of the reduction in electricity consumption in the example. Description of embodiments

[0019] In the following, suitable embodiments of an optical modulation device, an optical observation device and a light irradiation device according to one aspect of the present disclosure are described in detail with reference to the drawings.

[0020] The Fig. Figure 1 is a schematic view illustrating the configuration of the optical observation device according to one embodiment of the present disclosure. A Fig. The optical observation device 1 shown in Figure 1 is, for example, a fluorescence microscope that captures the fluorescence image of a sample S. The optical observation device 1 irradiates the surface of the sample S with inspection light Ld and captures as observation light Lf the light (fluorescence, reflected light, or the like) from the sample S that corresponds to the irradiation with the inspection light Ld, thereby obtaining the image of the sample S.

[0021] Examples of the sample S include cells containing fluorescent substances such as fluorescent dyes and fluorescent proteins, as well as biological samples. The sample S can be a semiconductor device, a film, or the like. The sample S emits the observation light Lf, for example, fluorescence, when irradiated with light (excitation light or illumination light) in a predetermined wavelength range. The sample S can be housed in a holder that is transparent to the inspection light Ld and the observation light Lf. In this case, the holder can be supported by a movable stage.

[0022] As in the Fig. As shown in Figure 1, the optical observation device 1 comprises a light source 2, a collimator lens 3, a polarization element 4, a polarization beam splitter 5, an optical modulation device 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.

[0023] Light source 2 emits light with a wavelength that serves as inspection light Ld to excite sample S. The inspection light Ld can be either coherent or incoherent. Examples of light sources that emit coherent light include laser diodes (LDs). Examples of light sources that emit incoherent light include light-emitting diodes (LEDs), superluminescent diodes (SLDs), and lamp light sources.

[0024] The collimating lens 3 collimates the inspection light Ld emitted by the light source 2. The polarizing element 4 transmits the inspection light Ld selectively according to a polarization component. The polarizing element 4 is, for example, a polarizing filter or the like. 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 transmitted by the polarizing element 4 towards the optical modulation device 21.

[0025] The optical modulation device 21 is a spatial light modulator that modulates the phase or phase difference (delay) of the inspection light Ld. In the present embodiment, the optical modulation device 21 is configured as a reflective spatial light modulator. The optical modulation device 21 modulates the inspection light Ld and outputs modulated light Lm. The modulated light Lm output by the optical modulation device 21 is transmitted through the polarization beam splitter 5 and directed to the first optical system 6.

[0026] The optical modulation device 21 is electrically connected to the control unit C and forms a spatial light modulation unit. The operation of the optical modulation device 21 is controlled by the control unit C. The optical modulation device 21 performs the following functions in the optical observation device 1: limiting the position of the irradiation point of the inspection light Ld (modulated light Lm) with which the sample S is irradiated, moving the position, simultaneously forming a plurality of irradiation points, controlling the phase, and the like.

[0027] The first optical system 6 optically couples the optical 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 emitted by the optical modulation device 21 at the pupil position of the objective lens 8.

[0028] The beam splitter 7 is an optical element that separates the modulated light Lm and the observation light Lf. The beam splitter 7 can be a polarizing beam splitter or a dichroic mirror. The beam splitter 7 is configured, for example, to transmit modulated light Lm with an excitation wavelength and to reflect observation light Lf with a fluorescence wavelength. Depending on the configurations of the optical systems (for example, the first optical system 6 and the second optical system 9) before and after the beam splitter 7, or the type of microscope on which the optical observation device 1 is used, the beam splitter 7 can be configured to reflect the modulated light Lm and transmit the observation light Lf.

[0029] The objective lens 8 condenses the modulated light Lm, irradiates the sample S with the modulated light Lm, and directs the observation light Lf from the sample S to the detector 10 according to the irradiation with the modulated light Lm in conjunction with the beam splitter 7. The objective lens 8 can be configured to be movable along the optical axes of the modulated light Lm and the observation light Lf by a control element, such as a piezo actuator or a stepper motor. In this case, it is possible to adjust the focusing position of the modulated light Lm and the focus position of the observation light Lf as desired.

[0030] 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 produces an image of the observation light Lf from the objective lens 8 onto the light-receiving surface of the detector 10.

[0031] The detector 10 is a device that detects the observation light Lf. The detector 10 includes, for example, an image sensor such as a CCD image sensor or a CMOS image sensor. The detector 10 images the observation light Lf generated by the second optical system 9 onto the light-receiving surface.

[0032] The control unit C is physically a computer system comprising a storage device such as RAM or ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, and the like. The computer can be, for example, a personal computer, a cloud server, or a smart device (smartphone, tablet, or the like). The control unit C causes a computer to execute a program to control the operation of the light source 2, the objective lens 8, the detector 10, and the like in the optical observation device 1, or a program to control a phase modulation amount or a phase difference modulation amount (retardation modulation amount) in the optical modulation device 21, and performs the desired control.

[0033] The Fig. Figure 2 is a schematic view illustrating the configuration of a light irradiation device according to an embodiment of the present disclosure. The light irradiation device 11 is obtained by combining the beam splitter 7, the objective lens 8, the second optical system 9, and the detector 10 from the [reference to be added] in the Fig. The configuration of the optical observation device 1 shown in Figure 1 is removed. That is, the light irradiation device 11 comprises the light source 2, the collimating lens 3, the polarizing element 4, the polarizing beam splitter 5, the optical modulation device 21, the first optical system 6, and the control unit C.

[0034] In the light irradiation device 11, the sample S is irradiated with the modulated light Lm, which is emitted by the optical modulation device 21 through the polarization beam splitter 5 and the first optical system 6. The optical modulation device 21 performs the following functions in the light irradiation device 11: limiting the position of the irradiation point of the inspection light Ld (modulated light Lm) with which the sample S is irradiated, moving the position, simultaneously forming a plurality of irradiation points, controlling the phase, and the like.

[0035] Next, the optical modulation device 21 described above will be described in more detail.

[0036] The Fig. Figure 3 is a schematic cross-sectional view illustrating the configuration of an optical modulation device according to one embodiment of the present disclosure. The Fig. The optical modulation device 21 shown in Figure 3 is a device that modulates the input light Lp and outputs it as modulated light Lm, using a reflective spatial light modulator as an example. The input light Lp is the inspection light Ld in the optical observation device 1 and the light irradiation device 11 described above. As shown in the Fig. As shown in Figure 3, the optical modulation device 21 comprises an electro-optic crystal 22, a transparent electrode 23, a slit buffer layer 24, a reflection unit 25, a drive substrate 26, a first power supply 27 and a second power supply 28.

[0037] The electro-optic crystal 22 has an input surface 22a, where the input light Lp is introduced, and a back surface 22b opposite the input surface 22a. The electro-optic crystal 22 has, for example, a perovskite crystal structure and changes its refractive index based on an electro-optic effect such as the Pockels effect or the Kerr effect. The electro-optic crystal 22 with a perovskite 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, for example, take on a value of approximately 1000 to 20000.

[0038] One such electro-optical crystal 22 is, for example, a KTa 1-x Note x O3 (0 ≤ x ≤ 1) -crystal (KTN crystal), a K 1-y Li y Ta 1-x Note xO3 (0 ≤ x ≤ 1, 0 < y < 1) crystal, a PLZT crystal or the like, and specific examples of this include BaTiO3, or K3Pb3(Zn2Nb7)O 27 , K(Ta 0.65 Note 0.35 )O3, Pb3MgNb2O9, and Pb3NiNb2O9.

[0039] In the present embodiment, the KTN crystal is used as the electro-optic crystal 22. Since the KTN crystal is a cubic m3m point group, it does not exhibit the Pockels effect and undergoes phase modulation based on the Kerr effect. Phase modulation can be achieved by introducing light parallel or perpendicular to the crystal axis of the electro-optic crystal 22 and applying an electric field in the same direction. Delay modulation can be achieved by rotating the other two axes about an arbitrary crystal axis at any angle other than 0° and 90°.

[0040] The Fig. 4(a) is a view that represents a relationship between a crystal axis, a direction of light propagation, and an electric field during delay modulation. Fig. Figure 4(b) is a view that represents each axis in a planar manner. An example is given here where the crystal is rotated by an angle of 45°. In a case where axes X2 and X3 are rotated by 45° about an axis X1 to define new axes X1, X2', and X3', delay modulation can be performed by introducing light parallel or perpendicular to axes X1, X2', and X3' into the electro-optic crystal 22. In the examples of Fig. 4(a) and Fig. 4(b) The application direction 1102 of the electric field is defined as parallel to the propagation direction 1101 of the input light in a crystal 1104. In this case, the Kerr coefficients used to modulate the input light Lp are g11, g12 and g44.

[0041] The relative permittivity of the KTN crystal can fluctuate due to temperature influence. For example, the relative permittivity increases to approximately 20,000 at about -5 °C, which corresponds to the highest value, and decreases to approximately 5,000 at about 20 °C, which corresponds to normal temperature. In the present embodiment, the optical modulation device 21 comprises, as shown in the Fig. Figure 3 shows a temperature control element 29. The temperature control element 29 is configured, for example, by a Peltier element. The temperature of the electro-optical crystal 22 during operation is maintained at approximately -5 °C by the temperature control element 29.

[0042] The transparent electrode 23 is provided on the side of the input surface 22a of the electro-optic crystal 22. The transparent electrode 23 consists, for example, of indium tin oxide (ITO) and is transparent to the input light Lp and the modulated light Lm. The input light Lp is transmitted through the transparent electrode 23 and introduced into the electro-optic crystal 22, and the light Lm modulated by the electro-optic crystal 22 is emitted to the outside from the optical modulation device 21 via the transparent electrode 23.

[0043] The gap buffer layer 24 is a layer that suppresses the propagation of the lateral electric field generated by the gap G. The gap buffer layer 24 is positioned 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 materials used for the gap buffer layer 24 include KTN, KTaO3, and KNbO3. Various film formation techniques, such as vacuum deposition, sputtering, pulsed laser deposition, atomic layer deposition, and spin coating, can be used to form the gap buffer layer 24 from, for example, polycrystalline or amorphous material. The gap buffer layer 24 can also be formed by material modification using ion implantation or plasma. In this case, examples of ion species used for the gap buffer layer 24 include B, N, C, F, Al, P, Li, Na, K, and Mg.

[0044] The relative permittivity of the slit buffer layer 24 is a value between the relative permittivity of the transparent electrode 23 and the relative permittivity of the electro-optic crystal 22. That is, if the relative permittivity of the transparent electrode 23 ε rtcо is the relative permittivity of the electro-optic crystal 22 ε rc is and the relative permittivity of the gap buffer layer 24 ε rf is, satisfies the relative permittivity ε rf the gap buffer layer 24 the condition ε rtcо < ε rf < ε rc .

[0045] If the relative permittivity of the electro-optic crystal is 22 ε rc and the relative permittivity of the gap buffer layer 24 ε rf is, satisfies the relative permittivity ε rf the gap buffer layer 24 in the present embodiment ε rc / 100 < ε rf < ε rc / 5. For example, the KTN crystal in the single-crystal state has a relative permittivity of approximately several tens of thousands, but in the thin-film state, the relative permittivity decreases to about 1 / 10 to 1 / 100 of that in the single-crystal state. Therefore, for example, by forming the electro-optic crystal 22 from the single-crystal body of the KTN crystal and by forming the slit buffer layer 24 from the thin film of the KTN crystal, the relative permittivity relationship can be easily satisfied.

[0046] The reflection unit 25 reflects the input light Lp, which reaches the back surface 22b of the electro-optic crystal 22, towards the transparent electrode 23. The reflection unit 25 comprises a plurality of pixel electrodes 30 arranged on the side of the back surface 22b of the electro-optic crystal 22. The pixel electrode 30 is a metal electrode, made, for example, of aluminum or a similar material. The pixel electrode 30 can be formed, for example, by metal vapor deposition using a mask pattern. For example, as shown in the Fig. 5(a) shows 25 pixel electrodes 30 in the reflection unit, which have a rectangular shape (square shape) in the top view, arranged in a matrix. In the example of the Fig. 5(a) the pixel electrodes 30 are arranged in a 4×4 arrangement for the sake of simplicity, but the number of arrangements of the pixel electrodes 30 is arbitrary.

[0047] The width (here the length of one side) of the pixel electrode 30 corresponds, for example, approximately to the thickness of the electro-optic crystal 22. If the width of the pixel electrode 30 is too large in relation to the thickness of the electro-optic crystal 22, it is assumed that the crosstalk of the electrical signals between the neighboring pixel electrodes 30 and 30 increases. Therefore, it is possible to suppress the crosstalk of the electrical signals between the neighboring pixel electrodes 30 and 30 by making the width of the pixel electrode 30 approximately equal to the thickness of the electro-optic crystal 22.

[0048] The driver substrate 26 applies an electric field between the transparent electrode 23 and the pixel electrode 30. The driver substrate 26 is a so-called CMOS substrate. The driver substrate 26 can be fixed, for example, to an organic substrate such as a glass-epoxy substrate (epoxy resin with a glass fiber sheet as the core material), a ceramic substrate, or the like. The driver substrate 26 comprises a plurality of driver electrodes 31, which are electrically connected to the plurality of pixel electrodes 30.

[0049] In the control substrate 26, for example, as in the Fig. Figure 5(b) shows the control electrodes 31, which have a rectangular (square) shape in plan view, arranged in a matrix with a spacing corresponding to that of the pixel electrodes 30. In the example of the Fig. 5(b) For the sake of simplicity, the control electrodes 31 are arranged in a 4×4 configuration, but the number of control electrodes 31 in each configuration corresponds to the number of pixel electrodes 30 in each configuration. Each control electrode 31 is equipped with a control switch 32. The application of a voltage to each pixel electrode 30 is controlled by actuating the switch 32.

[0050] As in the Fig. As shown in Figure 3, the control electrode 31 and the pixel electrode 30 are arranged such that they face each other in the thickness direction of the electro-optic crystal 22 and are individually electrically connected by a contact bump 33. The contact bump 33 consists, for example, of gold, solder, or the like. In a region between the electro-optic crystal 22 and the control substrate 26, a cavity can be formed between the adjacent pixel electrodes 30 and 30, as well as between the adjacent contact bumps 33 and 33, and an insulator can be arranged.

[0051] 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 the voltage to the transparent electrode 23. The second power supply 28 is electrically connected to the control substrate 26 and applies the voltage to the pixel electrode 30 via the control electrode 31. When the voltage of the transparent electrode 23 is V com and the voltage of the pixel electrode is 30 V px At the time of modulation, the voltage is applied to the transparent electrode 23 and the pixel electrode 30, such that, for example, V com ≥2×V px is fulfilled.

[0052] In the present embodiment, as described above, the plurality of control electrodes 31 and the plurality of pixel electrodes 30 are individually and electrically connected by contact bumps 33. Therefore, the electric field can be individually applied to each of the plurality of pixel electrodes 30 between the transparent electrode 23 and the pixel electrode 30. This suppresses crosstalk of the electrical signals between the pixel electrodes and contributes to improving modulation accuracy.

[0053] In the optical modulation device 21 described above, voltages are applied to the transparent electrode 23 and the pixel electrode 30 by the first power supply 27 and the second power supply 28, respectively. The refractive index of the electro-optic crystal 22 changes according to the electric field generated by the applied voltage. By applying a desired modulation pattern to the plurality of pixel electrodes 30, the input light Lp passing through the electro-optic crystal 22 is phase-modulated according to a change in the refractive index. The input light Lp is reflected by the pixel electrode 30, passes through the electro-optic crystal 22 to be phase-modulated again, and is emitted as modulated light Lm.

[0054] The configuration of the transparent electrode 23 described above is described in more detail below.

[0055] In the optical modulation device 21, the transparent electrode 23 has a gap G that divides the transparent electrode 23 into a plurality of electrode regions R, which face at least one of the plurality of pixel electrodes 30. In the present embodiment, the gap G is formed by a cavity 34, and the gap buffer layer 24 is exposed at the position of the gap G of the transparent electrode 23.

[0056] The gap G is formed at a position between the pixel electrodes 30 and 30 arranged in a matrix and at a position that, in plan view, corresponds to the outer edge of the arrangement area of ​​the pixel electrodes 30. A portion of the gap G may overlap the edge of the pixel electrode 30 in plan view. The plurality of electrode areas R has a rectangular shape. The plurality of electrode areas R are separated from each other in the region of the gap G and connected to each other in a region that excludes the gap G.

[0057] For structuring the transparent electrode 23, including the gap G, methods such as etching, peeling, mask film deposition, or the like can be used. Examples of etching include dry etching such as plasma etching or reactive ion etching, and wet etching using an immersion or centrifugal etching process. Examples of peeling include liquid immersion peeling and laser lift-off. Examples of mask film deposition include a process using a metal mask.

[0058] The Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12 to Fig. Figure 13 are schematic top views that illustrate an example of the structuring of a transparent electrode. In the examples of Fig. 6 and Fig. In Figure 7, the multitude of electrode regions R is subdivided into rectangular shapes (square shapes) so that they correspond on a one-to-one basis to the pixel electrodes 30 arranged in a matrix. In the example of the Fig. 6. The gap G is provided such that it corresponds to the side section of each of the plurality of electrode regions R. In the adjacent electrode regions R and R', the side sections are separated from each other by the gap G, and the corner sections are connected to each other. The gap G is provided such that it also corresponds to the side section of each of the plurality of electrode regions R in a section corresponding to the outer edge of the transparent electrode 23. In the section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the side section can extend to the corner section, and the gaps G and G of the adjacent electrode regions R and R' can be connected to each other.

[0059] In the example of the Fig. In section 7, the gap G is provided such that it corresponds to the corner section of each of the plurality of electrode regions R. In the adjacent electrode regions R and R', the corner sections are separated from each other by the gap G, and the side sections are connected to each other. The gap G is provided such that it also corresponds to the corner section of each of the plurality of electrode regions R in a section corresponding to the outer edge of the transparent electrode 23. In the section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the corner section can extend to the side section, and the gaps G and G' of the adjacent electrode regions R and R' can be connected to each other.

[0060] In the examples of Fig. 8 and Fig. 13 The multitude of electrode regions R is divided into rectangular shapes (square shapes or elongated shapes) so that they correspond to the multitude of pixel electrodes 30. In the example of the Fig. In Figure 8, the plurality of electrode regions R is subdivided into elongated shapes corresponding to the 1×2 pixel electrodes 30. In adjacent electrode regions R and R', the side sections are separated from each other by the gap G, and the corner sections are connected. In the central section of the side section, which forms the longitudinal side of electrode region R, the gap G is divided in the direction of extension of the side section. The gap G is designed to correspond to the side section of each of the plurality of electrode regions R, even in a section corresponding to the outer edge of the transparent electrode 23. In the section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the side section can extend to the corner section, and the gaps G and G of the adjacent electrode regions R and R' can be connected.

[0061] In the example of the Fig. In Figure 9, the plurality of electrode regions R is subdivided into square shapes corresponding to the 2×2 pixel electrodes 30. In adjacent electrode regions R and R', the side sections are separated by the gap G, and the corner sections are connected. In the middle section of the side section, the gap G is divided in the direction of extension of the side section. The gap G is designed to correspond to the side section of each of the plurality of electrode regions R, even in a section corresponding to the outer edge of the transparent electrode 23. In the section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the side section can extend to the corner section, and the gaps G and G of the adjacent electrode regions R and R' can be connected.

[0062] In the example of the Fig. In Figure 10, the plurality of electrode regions R is subdivided into elongated shapes corresponding to the 1×2 pixel electrodes 30. In adjacent electrode regions R and R', the corner sections are separated from each other by the gap G, and the side sections are connected. The gap G is designed to correspond to the corner section of each of the plurality of electrode regions R, even in a section corresponding to the outer edge of the transparent electrode 23. In the section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the corner section can extend to the side section, and the gaps G and G' of adjacent electrode regions R and R' can be connected.

[0063] In the example of the Fig. In Figure 11, the plurality of electrode regions R is subdivided into square shapes corresponding to the 2×2 pixel electrodes 30. In adjacent electrode regions R and R', the corner sections are separated by the gap G, and the side sections are connected. The gap G is designed to correspond to the corner section of each of the plurality of electrode regions R, even in a section corresponding to the outer edge of the transparent electrode 23. In the section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the corner section can extend to the side section, and the gaps G and G of the adjacent electrode regions R and R' can be connected.

[0064] In the examples of Fig. 12 and Fig. 13 The gap G is designed such that it corresponds to both the side section and the corner section of each of the plurality of electrode regions R. In the example of the Fig. In 12, the multitude of electrode regions R is subdivided into elongated shapes corresponding to the 1×2-pixel electrodes 30. In adjacent electrode regions R and R', the corner sections are separated from each other by the gap G, and the side sections are separated from each other by the gap G. Between the gap G at the corner section and the gap G at the side section, the gaps G and G are separated from each other, and the adjacent electrode regions R and R' are connected at the separated section. In a section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the corner section and the gap G corresponding to the side section can be connected.

[0065] In the example of the Fig. In 13, the multitude of electrode regions R is subdivided into square shapes, corresponding to the 2×2 pixel electrodes 30. In the adjacent electrode regions R and R', the corner sections are separated from each other by the gap G, and the side sections are separated from each other by the gap G'. Between the gap G at the corner section and the gap G at the side section, the gaps G and G' are separated from each other, and the adjacent electrode regions R and R' are connected at the separated section. In a section corresponding to the outer edge of the transparent electrode 23, the gap G corresponding to the corner section and the gap G corresponding to the side section can be connected.

[0066] The Fig. Figure 14 is a schematic view illustrating the functions and effects of a slit buffer layer and a slit. In the optical modulation device described above, the relative permittivity of the electro-optic crystal is relatively high (in the present embodiment, about 1000 to 20000), and therefore it is important to effectively apply an electric field in the thickness direction of the electro-optic crystal. If an electric field propagates in a lateral direction intersecting the thickness direction (hereinafter referred to as the "lateral electric field") and the value of the lateral electric field increases, it is assumed that the stability of the light modulation will be difficult to achieve.

[0067] As in the Fig. As shown in 14, in the comparative example where the gap buffer layer and the gap are not provided, if a voltage V pxWhen a potential difference is applied to the pixel electrode and a potential difference is generated between the adjacent pixel electrodes, the phase modulation magnitude is disturbed in a region R1 corresponding to the edge of the pixel electrode. In region R1, it is difficult to distinguish the voltage applied to the electro-optical crystal from the actual voltage V applied to the pixel electrode. px to control, and it is difficult to achieve stability in light modulation.

[0068] In the comparative example, the phase modulation magnitude is not flat even in region R2, which corresponds to the central section of the pixel electrode, and a curved section may occur. It is assumed that the value of the lateral electric field in region R3 outside the edge of the pixel electrode becomes relatively high, and the contrast between the phase modulation magnitude in region R2 and the phase modulation magnitude in region R3 decreases.

[0069] Meanwhile, in the optical modulation device 21, the transparent electrode 23 is divided by the slit G into a plurality of electrode regions R, each 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 is generated that is smaller than the electric field generated by the pixel electrode 30 between the transparent electrode 23 and the slit G. Therefore, the electric field in region R1, corresponding to the edge of the pixel electrode 30, can be amplified, and the lateral electric field generated at the edge of the pixel electrode 30 can undergo dispersion in the lateral direction (direction of arrangement of the pixel electrodes 30). Therefore, as shown in the Fig. 14 shows that the disturbance of the phase modulation amount in the area R1, which corresponds to the edge of the pixel electrode, is eliminated, and the phase modulation amount is also flattened in the area R2, which corresponds to the middle section of the pixel electrode 30.

[0070] In this optical modulation device 21, the relative permittivity of the slit buffer layer 24 is a value that lies between the relative permittivity of the transparent electrode 23 and the relative permittivity of the electro-optic crystal 22. By arranging the slit buffer layer 24, the loss of the electric field between the transparent electrode 23 and the electro-optic crystal 22 can be suppressed, and the lateral electric field subjected to dispersion by the formation of the slit G can be smoothed. This also helps to eliminate the disturbance of the phase modulation magnitude in region R1, which corresponds to the edge of the pixel electrode, and reduces the value of the lateral electric field in region R3 outside the edge of the pixel electrode, thus improving the contrast between the phase modulation magnitude in region R2 and the phase modulation magnitude in region R3.Therefore, stable light modulation can be achieved in the optical modulation device 21.

[0071] Since the gap buffer layer 24 is arranged 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, and an effect to suppress unexpected charge movements is also achieved. This allows for more stable light modulation and can also be expected to suppress charge injection.

[0072] The present embodiment includes an aspect in which the plurality of electrode regions R have a rectangular shape and the gap G is provided such that it corresponds to the side section of each of the plurality of electrode regions R. According to such a configuration, the lateral electric field is further smoothed in the direction in which the side sections of the plurality of electrode regions R are connected to each other.

[0073] The present embodiment includes an aspect in which the plurality of electrode regions R has a rectangular shape and the gap G is provided such that it corresponds to the corner section of each of the plurality of electrode regions R. According to such a configuration, the lateral electric field is further smoothed in the direction in which the side sections of the plurality of electrode regions R are connected to each other.

[0074] The present embodiment includes an aspect in which the plurality of electrode regions R has a rectangular shape and the gap G is provided such that it corresponds to both the side section and the corner section of each of the plurality of electrode regions R. According to such a configuration, the lateral electric field is further smoothed both in the direction in which the side sections of the plurality of electrode regions face each other and in the direction in which the corner sections face each other.

[0075] In the present embodiment, the plurality of electrode regions R are interconnected at sections that exclude the gap G. Since the plurality of electrode regions R are interconnected, a voltage can be applied uniformly across the plurality of pixel electrodes 30.

[0076] If the relative permittivity of the electro-optic crystal is 22 ε rcand the relative permittivity of the gap buffer layer 24 ε rf is, is in the present embodiment ε rf , ε rc / 100 < ε rf < ε rc / 5 is satisfied. By satisfying such a relative permittivity relation, the loss of the electric field between the transparent electrode 23 and the electro-optic crystal 22 can be suppressed more effectively.

[0077] In the present embodiment, the gap G is formed by the cavity 34. By forming the gap G as a cavity, the lateral electric field generated at the edge of the pixel electrode 30 can undergo more reliable lateral dispersion.

[0078] In the present embodiment, the optical modulation device 21 comprises the control substrate 26 with the plurality of control electrodes 31, which are electrically connected to the plurality of pixel electrodes 30, the first power supply 27, which is electrically connected to the transparent electrode 23, and the second power supply 28, which is electrically connected to the control substrate 26. By using two power supply systems, one on the side of the transparent electrode and one on the side of the control substrate, it is possible to apply a voltage to the transparent electrode that is independent of the dielectric strength of the control substrate and the control method. This allows the degrees of freedom of the modulation pattern for the input light Lp to be improved.

[0079] The Fig. Figure 15 is a schematic cross-sectional view showing the configuration of an optical modulation device according to a modification. As shown in the Fig. As shown in Figure 15, an optical modulation device 41 according to the modification differs from the optical modulation device 21 described above in that the slit G is formed by a

[0080] The insulator 44 is preferably transparent to the input light Lp and the modulated light Lm. Examples of materials for forming the insulator 44 are SiO2, SiN, and hydrogensilsesquioxane (HSQ). By forming the gap G as the insulator 44, the lateral electric field generated at the edge of the pixel electrode 30 can undergo more reliable lateral dispersion. Since the plurality of electrode regions R are surrounded by the insulator 44, a voltage can be applied uniformly across the plurality of pixel electrodes 30.

[0081] In the present embodiment, the insulator 44 is structured on the gap buffer layer 24, and the transparent electrode 23 is provided on the entire surface of the gap buffer layer 24 to cover the insulator 44. That is, in the present embodiment, the transparent electrode 23 is divided by the gap G, which is the insulator 44, into the plurality of electrode regions R, and the plurality of electrode regions R are connected to each other by the electrode section of the transparent electrode 23, which is provided such that it covers the gap G.

[0082] The Fig. Figure 16 is a schematic top view that illustrates the structuring of a column. In the Fig. 16, Fig. 17 to Fig. Figure 18 shows the electrode section of the transparent electrode 23, which is designed to cover the gap G; this figure has been omitted for the sake of simplicity. In the example of the Fig. The plurality of electrode regions R are subdivided into rectangular shapes (square shapes) so that they correspond to the pixel electrodes 30, which are arranged in a matrix on a one-to-one basis. The gap G, which is the insulator 44, is provided in a grid shape between the plurality of electrode regions R and in a section corresponding to the outer edge of the transparent electrode 23.

[0083] In the example of the Fig. In 17, the plurality of electrode regions R is subdivided into elongated shapes, corresponding to the 1×2 pixel electrodes 30. The gap G, which is the insulator 44, is provided in a grid shape between the plurality of electrode regions R and in a section corresponding to the outer edge of the transparent electrode 23. In the example of the Fig. In Figure 18, the plurality of electrode regions R is subdivided into square shapes, corresponding to the 2×2 pixel electrodes 30. The gap G, which is the insulator 44, is provided in a grid shape between the plurality of electrode regions R and in a section corresponding to the outer edge of the transparent electrode 23.

[0084] It should be noted that in a case where the gap G is formed by the insulator 44, it is not always necessary to provide a configuration in which the plurality of electrode regions R are interconnected by the electrode section of the transparent electrode 23, which is designed to cover the gap G as in the optical modulation device 41 described above. For example, in the Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12 to Fig. In the structure of the transparent electrode 23 shown in Figure 13, the gap G caused by the cavity 34 is replaced by the gap G caused by the insulator 44.

[0085] Next, the efficacy test of the present disclosure will be described.

[0086] This test will be conducted in the Fig. 19(a) the calculation model 101 shown is assumed and a phase modulation set is simulated in a case in which the voltage V pxthe pixel electrode 30 is modified. In the computational model 101 of the example, an electro-optic crystal 122 is a KTN crystal, a gap buffer layer 124 and a transparent electrode 123 are arranged on the input face of the electro-optic crystal 122, and a plurality of pixel electrodes 130 are arranged on the back face of the electro-optic crystal. A gap G caused by a cavity was arranged in the transparent electrode 123 such that it corresponds to a position that is defined as the boundary between the pixel electrode 130 with an applied voltage of 0 V and the pixel electrode 130 with an applied voltage of V. px serves.

[0087] The parameters used in the phase modulation simulation are listed in the Fig. 19 summarized. Here, the wavelength of the input light was 632.8 nm, the thickness of the electro-optic crystal was 50 µm, the relative permittivity of the electro-optic crystal was 20000, the refractive index of the electro-optic crystal was 2.318, the Kerr coefficient g12 was -0.038, the thickness of the slit buffer layer was 0.5 µm and the relative permittivity of the slit buffer layer was 2000.

[0088] In calculation model 101, a calculation model in which the gap buffer layer 124 and the gap G in the transparent electrode 123 were omitted was used as the calculation model for comparison example 1. In calculation model 101, a calculation model in which the gap G in the transparent electrode 123 was defined and the gap buffer layer 124 was omitted was used as the calculation model for comparison example 2.

[0089] The Fig. Figure 20(a) is a view that represents the simulation result of comparison example 1, and the Fig. Figure 20(b) is a view that presents the simulation result of comparison example 2. Fig. Figure 20(c) is a view showing the simulation result of the example. In these drawings, the horizontal axis represents position X in an in-plane direction, and the vertical axis represents the total. The total is the total number of amplitudes of the electric field component of the input light introduced at position X in the in-plane direction. As shown in the Fig. 20(a) and Fig. As shown in Figure 20(b), in comparison examples 1 and 2, the total number in the area corresponding to the middle part of the pixel electrode is not flat, and the total number in the area corresponding to the edge of the pixel electrode is also perturbed.

[0090] As in the Fig. In contrast to example 20(c), in example 3 the total number in the area corresponding to the central part of the pixel electrode is flat, and the disturbance of the total number in the area corresponding to the edge of the pixel electrode is also suppressed. It is evident that the contrast between the total number in the area of ​​the pixel electrode and the total number in the area outside the edge of the pixel electrode is also improved compared to examples 1 and 2.

[0091] The Fig. 21, Fig. 22, Fig. 23, Fig. 24 to Fig. 25 are views representing the results of the quantitative evaluation, divided into a range of 60 ≤ X < 100 (a range in which the applied voltage V px is) and a range of 100 ≤ X ≤ 150 (a range in which the applied voltage is 0 V), based on the results of the Fig. 20. The Fig. Figures 21(a) to 21(c) are views representing the first-order dispersions of the totals in 60 ≤ X < 100, where the Fig. 21(a) represents the result of comparison example 1, which Fig. 21(b) represents the result of comparison example 2 and the Fig. 21(c) represents the result of the example. As in the Fig. As shown in Figures 21(a) to 21(c), it was confirmed that the first-order dispersion of the total number of particles in the example is smaller than that of comparison examples 1 and 2 in 60 ≤ X < 100. In comparison examples 1 and 2, the first-order dispersion of the total number of particles decreases with increasing applied voltage V. px generally, but in this example the first-order dispersion of the total number fluctuates even with increasing applied voltage V. px hardly and is applied in relation to each of the applied voltages V px suppressed to less than 0.002.

[0092] The Fig. 22(a) to 22(c) are views representing the first-order dispersions of the totals in 100 ≤ X ≤ 150, where the Fig. 22(a) represents the result of comparison example 1, which Fig. 22 (b) represents the result of comparison example 2 and the Fig. 22(c) represents the result of the example. As in the Fig. As shown in Figures 22(a) to 22(c), it was confirmed that the first-order dispersion of the total number of particles in the example is smaller than even that of comparison examples 1 and 2 in 100 ≤ X ≤ 150. In comparison examples 1 and 2, the first-order dispersion of the total number of particles decreases with increasing applied voltage V. px generally, but in this example the first-order dispersion of the total number fluctuates even with increasing applied voltage V. px hardly and is applied in relation to each of the applied voltages V px Suppressed to almost 0.

[0093] The Fig. Figures 23(a) to 23(c) are views representing the average values ​​of the totals in 60 ≤ X < 100, where the Fig. 23(a) represents the result of comparison example 1, which Fig. 23(b) represents the result of comparison example 2 and the Fig. 23(c) represents the result of the example. In 60 ≤ X < 100, as in the Fig. As shown in 23(a) to 23(c), the average value of the totals in each of the comparative examples 1 and 2 and the example tends to increase with increasing applied voltage V. px to decrease. With the same applied voltage V px It can be seen that the average value of the total numbers in the examples is smaller than in comparison examples 1 and 2.

[0094] The Fig. 24(a) to 24(c) are views representing the average values ​​of the totals in 100 ≤ X ≤ 150, where the Fig. 24(a) represents the result of comparison example 1, which Fig. 24(b) represents the result of comparison example 2 and the Fig. 24(c) represents the result of the example. As in the Fig. 24(a) and Fig. Figure 24(b) shows in comparative examples 1 and 2 that, despite an applied voltage of 0 V, under the influence of a section on which V px When applied (a range of 60 ≤ X < 100), the average of the totals shows the same trend as that of the range 60 ≤ X < 100. As in the Fig. As shown in 24(c), the average value of the total numbers in the example is also the same when the applied voltage V is increased. px essentially constant. Therefore, the example confirmed that the influence of the lateral electric field of the neighboring pixel is reduced.

[0095] The Fig. Figures 25(a) to 25(c) are views that represent the simulation results of the phase modulation amounts, where the Fig. 25(a) represents the result of comparison example 1, which Fig. 25(b) represents the result of comparison example 2 and the Fig. 25(c) represents the result of the example. Here, the difference between the average value of the total numbers in 100 ≤ X ≤ 150 and the average value of the total numbers in 60 ≤ X < 100 was defined as the phase modulation amount θ. As in the Fig. As shown in Figures 25(a) to 25(c), the phase modulation magnitude θ in each of the comparison examples 1 and 2 and the example tends to increase with increasing applied voltage V. px to increase, but it is evident that the phase modulation amount θ in the example is larger than in comparison examples 1 and 2 at the same applied voltage V. px .

[0096] The above results confirmed that the configuration in which the gap is provided in the transparent electrode to divide the transparent electrode into the plurality of electrode regions, and the gap buffer layer in which the relative permittivity assumes a value between that of the transparent electrode and the electro-optic crystal, as provided in the present disclosure, contributes to the realization of the stable light modulation of the optical modulation device.

[0097] The Fig. Figure 26 is a diagram that presents the calculation results of modulation quality figures in comparison examples 1 and 2 and the example. This diagram illustrates the relationship between a bias ratio V br and a phase modulation amount when the voltage V comThe transparent electrode is set to 30 V. The phase modulation amount is a value calculated as the difference between the average of the total values ​​in the range where position X in the in-plane direction satisfies 100 < X ​​< 150 and the average of the total values ​​in the range where position X in the in-plane direction satisfies 60 ≤ X < 100. The bias ratio V br is a parameter that is represented by ΔV px / V com is calculated. A modulation quality α is a parameter that is expressed by θ / V br is calculated when the phase modulation magnitude θ is, and is a value obtained by quantifying the efficiency of the phase modulation magnitude with respect to the applied voltage. In the calculation, V was used. px in the range of 100 < X ​​< 150 set to 0 V, and V px was set so that V brin the other areas it was 0.5 or less. The phase modulation amount was calculated based on the difference between the average values ​​in the area where V px 0 V, and calculated for the other areas.

[0098] As in the Fig. As shown in Figure 26, the modulation quality α in Comparative Example 1 was 0.733 and the modulation quality α in Comparative Example 2 was 0. In the example, however, the modulation quality α was 1.255, and it was confirmed that the modulation quality α is improved by the configuration of the present disclosure and the efficiency of the phase modulation amount is improved.

[0099] The Fig. Figure 27 is a diagram illustrating the result of the power consumption reduction in the example. This diagram shows the relationship between the phase modulation magnitude θ and the applied voltage V. px between a case in which, in example 1, the voltage Vcom the transparent electrode is 30 V, and in a case where the voltage V com The transparent electrode is 60 V. As in the Fig. As shown in 27, the phase modulation amount in the case of applying the same V px in the case of V com of 30 V greater than in the case of V com of 60 V.

[0100] This result is probably due to the fact that with increasing voltage V com With the transparent electrode, the disturbance of the phase modulation increases, and the phase modulation magnitude undergoes dispersion in the lateral direction. It was suggested that reducing the voltage V com The transparent electrode reduces disturbances in phase modulation and suppresses the dispersion of the phase modulation amount in the lateral direction, thus enabling more effective stabilization of the phase modulation amount. Reference symbol list 1 optical observation device 2 light sources 6. First optical system (optical system) 10 Detector 11 Light irradiation device 21, 41 optical modulation device 22 electro-optical crystal 22a Entrance area 22b Back surface 23 transparent electrode 24 Gap buffer layer 25 reflection units 26 Control substrate 27 first power supply 28 second power supply 30-pixel electrode 31 Control electrode 34 Cavity 44 Insulator LP entrance light lm modulated light G gap R electrode area S Sample QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2017 / 213098 A

[0003]

Claims

[1] An optical modulation device that modulates input light and outputs the modulated input light as modulated light, the optical modulation device comprising: an electro-optical crystal with an input surface at which the input light is introduced, and a back surface opposite the input surface; a transparent electrode that is provided on the side of an input surface of the electro-optical crystal and transmits input light; a gap buffer layer provided between the transparent electrode and the electro-optic crystal; and a reflection unit with a plurality of pixel electrodes arranged on one side of the back surface of the electro-optic crystal, reflecting the input light reaching the back surface towards the transparent electrode, where a relative permittivity of the slit buffer layer is a value between a relative permittivity of the transparent electrode and a relative permittivity of the electro-optic crystal and the transparent electrode has a gap that divides the transparent electrode into a plurality of electrode regions, which face at least one of the plurality of pixel electrodes. [2] The optical modulation device according to claim 1, where the multitude of electrode areas have a rectangular shape and The gap is designed to correspond to the side section of each of the multiple electrode areas. [3] The optical modulation device according to claim 1, where the multitude of electrode areas have a rectangular shape and The gap is designed so that it corresponds to the corner section of each of the multiple electrode areas. [4] The optical modulation device according to claim 1, where the multitude of electrode areas have a rectangular shape and The gap is designed to correspond to both a side section and a corner section of each of the multitude of electrode areas. [5] The optical modulation device according to any one of claims 1 to 4, wherein the plurality of electrode regions are connected to each other at sections that exclude the gap. [6] The optical modulation device according to any one of claims 1 to 5, wherein, when the relative permittivity of the electro-optic crystal ε rc is and the relative permittivity of the gap buffer layer ε rf is, ε rc / 100 < ε rf < ε rc / 5 is fulfilled. [7] The optical modulation device according to any one of claims 1 to 6, wherein the slit is formed by a cavity. [8] The optical modulation device according to any one of claims 1 to 6, wherein the gap is formed by an insulator. [9] The optical modulation device according to any one of claims 1 to 8, further comprising: a control substrate with a plurality of control electrodes that are electrically connected to the respective plurality of pixel electrodes; a first power supply that is electrically connected to the transparent electrode; and a second power supply that is electrically connected to the control substrate. [10] An optical observation device comprising: a light source that emits the entrance light; the optical modulation device according to any one of claims 1 to 9, an optical system that directs the modulated light emitted by the optical modulation device to a sample; and a detector that captures light from the sample. [11] A light irradiation device comprising: a light source that emits the entrance light; the optical modulation device according to any one of claims 1 to 9, and an optical system that directs the modulated light emitted by the optical modulation device to a sample.

Images