Optical forming device and optical modulation device

Abstract

An optical forming device and an optical modulation device are provided. The optical forming device includes a resin tank containing a photocurable resin, a light source that emits light for curing the photocurable resin, and an optical modulator. The optical modulator includes a liquid crystal, a first substrate and a second substrate sandwiching the liquid crystal, and a first electrode and a second electrode for applying a voltage to the liquid crystal. The optical modulator modulates light that cures the photocurable resin in a pattern based on the shape of a three-dimensionally formed object and irradiates the photocurable resin with the modulated light. The optical modulator includes a plurality of modulation regions, each comprising a first region and a second region having mutually different voltage transmission characteristics.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Japanese Patent Application No. 2020-170625, filed October 8, 2020, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application generally relates to an optical forming device and an optical modulating device. Background Art

[0004] Technologies for shaping a three-dimensional object by irradiating a photocurable resin with light based on the cross-sectional shape of the object are known. For example, Japanese Unexamined Patent Application Publication No. H07-232383 describes an apparatus for shaping a three-dimensional object by selectively irradiating a photocurable resin with light using a liquid crystal shutter, and a method for shaping the object.

[0005] In Japanese Unexamined Patent Application Publication No. H07-232383, a liquid crystal shutter is used to selectively illuminate a photocurable resin with light, curing a layer of the photocurable resin. The cured resin then moves away from the liquid crystal shutter. Then, the liquid crystal shutter is used to selectively illuminate a layer of photocurable resin poured onto the cured resin, curing the next layer of the resin. In Japanese Unexamined Patent Application Publication No. H07-232383, these steps are repeated to form a three-dimensional object.

[0006] When molding objects with wide cross-sectional areas at high resolution, the device disclosed in Japanese Unexamined Patent Application Publication No. H07-232383 must be equipped with a large, high-definition liquid crystal shutter. Many driver integrated circuits (ICs) are required to drive the large, high-definition liquid crystal shutter, and the circuitry for driving such a shutter is complex.

[0007] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide an optical forming device and an optical modulation device capable of forming a forming object having a wide cross-sectional area with high resolution and with a simple configuration. Summary of the Invention

[0008] In order to achieve the above-mentioned object, an optical forming device according to a first aspect of the present disclosure includes:

[0009] a resin tank containing a light-curable resin;

[0010] a light source that emits light for curing the photocurable resin; and

[0011] An optical modulator comprising a liquid crystal, a first substrate and a second substrate sandwiching the liquid crystal, and a first electrode and a second electrode applying a voltage to the liquid crystal; modulating light in a pattern based on the shape of a three-dimensionally formed object; and irradiating the modulated light onto a photocurable resin, wherein

[0012] The optical modulator includes a plurality of modulation regions including a first region and a second region having mutually different voltage transmission characteristics.

[0013] The liquid crystal is aligned in a direction parallel to a major surface of the first substrate, and the first electrode and the second electrode apply a voltage to the liquid crystal to rotate the liquid crystal in a plane parallel to the major surface of the first substrate, in a first state in which a predetermined first voltage is applied to the liquid crystal, the first region and the second region have a transmittance lower than a predetermined transmittance,

[0014] In a second state in which a predetermined second voltage is applied to the liquid crystal, the first region has a transmittance greater than or equal to a predetermined transmittance, and the second region has a transmittance lower than the predetermined transmittance, and in a third state in which a predetermined third voltage is applied to the liquid crystal, the first region and the second region have a transmittance greater than or equal to the predetermined transmittance,

[0015] In a fourth state in which a predetermined fourth voltage is applied to the liquid crystal, the first region has a transmittance less than a predetermined transmittance, and the second region has a transmittance greater than or equal to the predetermined transmittance, and when the transmittance of the first region or the second region is greater than or equal to the predetermined transmittance, the photocurable resin is cured.

[0016] An optical modulation device according to a second aspect of the present disclosure includes:

[0017] a plurality of modulation regions including a first region and a second region having mutually different voltage-transmittance characteristics and modulating incident light;

[0018] liquid crystal, a first substrate and a second substrate sandwiching the liquid crystal, and a first electrode and a second electrode applying a voltage to the liquid crystal, wherein

[0019] The liquid crystal is aligned in a direction parallel to the main surface of the first substrate, and the first electrode and the second electrode apply a voltage to the liquid crystal to rotate the liquid crystal in a plane parallel to the main surface of the first substrate,

[0020] In a first state where a predetermined first voltage is applied to the liquid crystal, the first region and the second region have a transmittance lower than a predetermined transmittance,

[0021] In a second state in which a predetermined second voltage is applied to the liquid crystal, the first region has a transmittance greater than or equal to a predetermined transmittance, and the second region has a transmittance lower than the predetermined transmittance,

[0022] In a third state in which a predetermined third voltage is applied to the liquid crystal, the first region and the second region have a transmittance greater than or equal to a predetermined transmittance, and

[0023] In a fourth state in which a predetermined fourth voltage is applied to the liquid crystal, the first region has a transmittance less than a predetermined transmittance, and the second region has a transmittance greater than or equal to the predetermined transmittance.

[0024] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the disclosure.

[0025] According to the present disclosure, the number of driver ICs required to drive an optical modulator can be reduced, and a shaped object having a wide cross-sectional area can be shaped at high resolution with a simple configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] A more complete understanding of the present application can be obtained when the following detailed description is considered in conjunction with the following drawings, in which:

[0027] Figure 1 is a diagram showing the configuration of an optical forming device according to Example 1;

[0028] Figure 2 is a schematic diagram showing an optical forming device according to Example 1;

[0029] Figure 3 is a top view showing an optical modulator according to Example 1;

[0030] Figure 4 yes Figure 3 A cross-sectional view of the optical modulator shown in FIG. 1 taken along line AA;

[0031] Figure 5 is a top view showing a modulation region according to Example 1;

[0032] Figure 6 is a diagram showing voltage transmission characteristics of the first region, the second region, and the third region according to Example 1;

[0033] Figure 7 is a plan view showing areas through which curing light is transmitted, showing the first area and the second area according to Example 1;

[0034] Figure 8 is a flowchart illustrating a method for forming a three-dimensional shaped object according to Embodiment 1;

[0035] Figure 9 is a plan view showing a modulation region, a polarization axis of a first polarizing plate, and a polarization axis of a second polarizing plate according to Example 2;

[0036] Figure 10 is a graph showing voltage transmission characteristics of the first region and the second region according to Example 2 when the tilt angle θ=10°;

[0037] Figure 11 is a graph showing voltage transmission characteristics of the first region and the second region according to Example 2 when the tilt angle θ=15°;

[0038] Figure 12 is a plan view showing a modulation area, a polarization axis of a first polarization plate, and a polarization axis of a second polarization plate according to a modified example; and

[0039] Figure 13 is a graph showing voltage transmission characteristics of the first region and the second region according to a modified example. DETAILED DESCRIPTION

[0040] Hereinafter, an optical forming device according to various embodiments is described while referring to the accompanying drawings.

[0041] Example 1

[0042] Reference Figures 1 to 8 The optical forming device 100 according to the present embodiment will be described while the optical forming device 100 is used to form a three-dimensional object Ob from a photocurable resin RL.

[0043] like Figure 1 and Figure 2 As shown, the optical forming device 100 includes a resin tank 10, a forming plate 20, a mover 30, a light source 40, an optical modulator 50 and a controller 90 in a housing 5. The resin tank 10 contains a photocurable resin RL. The three-dimensional object Ob is formed on the surface 20a of the forming plate 20. The mover 30 moves the forming plate 20. The light source 40 emits light that cures the photocurable resin RL. The optical modulator 50 modulates this light that cures the photocurable resin RL in a pattern based on the shape of the three-dimensional object Ob. The controller 90 controls the various components of the optical forming device 100. In this specification, for ease of understanding, Figure 2 In the optical forming device 100, the rightward direction (rightward direction on the paper) is referred to as the "+X direction," the upward direction (upward direction on the paper) is referred to as the "+Z direction," and the direction perpendicular to the +X and +Z directions (forward direction on the paper) is referred to as the "+Y direction." The light that causes the photocurable resin RL to cure is also referred to as "curing light."

[0044] like Figure 2 As shown, the resin tank 10 of the optical forming apparatus 100 contains a photocurable resin RL. The resin tank 10 is a box-shaped container. The +Z direction surface of the resin tank 10 is open. The resin tank 10 has a bottom 12 and a wall 14.

[0045] The bottom 12 of the resin tank 10 transmits the curing light emitted from the light source 40. In one example, the bottom 12 is implemented as a flat glass. The wall 14 of the resin tank 10 blocks the curing light. The wall 14 is formed of resin, metal, etc.

[0046] Next, the photocurable resin RL will be described. The photocurable resin RL is implemented as a liquid resin that cures by being irradiated with light of a predetermined wavelength. In the present embodiment, the photocurable resin RL cures by being irradiated with light (curing light) emitted from the light source 40. The photocurable resin RL includes monomers, oligomers, a polymerization initiator, and the like. The polymerization initiator absorbs the curing light emitted from the light source 40 to generate active substances such as free radicals and ions, and causes the monomers, oligomers, and the like to initiate a polymerization reaction. In the present embodiment, the photocurable resin RL is an ultraviolet (UV) curable resin.

[0047] The forming plate 20 of the optical forming device 100 is a flat plate made of resin or metal. Figure 2 As shown, the shaping plate 20 is positioned on the +Z side relative to the bottom 12 of the resin pot 10. In the initial state of the optical shaping device 100, the shaping plate 20 is positioned in the resin pot 10 (initial position of the shaping plate 20). The shaping plate 20 is moved in the +Z direction and the -Z direction by the mover 30. The three-dimensional object Ob is shaped on the surface 20a of the shaping plate 20. The surface 20a faces the bottom 12 of the resin pot 10.

[0048] The mover 30 of the optical forming device 100 moves the forming plate 20 in the +Z direction and the -Z direction. The mover 30 includes an arm 32 and a moving mechanism 34. The arm 32 of the mover 30 connects the forming plate 20 to the moving mechanism 34. The moving mechanism 34 of the mover 30 moves the forming plate 20 in the +Z direction and the -Z direction via the arm 32. The moving mechanism 34 includes a motor, a ball screw, a slide, etc. (not shown in the figure).

[0049] The light source 40 of the optical forming device 100 emits curing light (i.e., light that cures the light-curable resin RL) toward the light-curable resin RL (in the +Z direction). In the present embodiment, the light source 40 is arranged on the -Z side of the resin pot 10. The light source 40 emits UV light in the +Z direction from a top surface 40a positioned on the side of the resin pot 10. The light source 40 includes a reflective sheet, a light-emitting diode (LED) that emits UV light, a diffuser, and the like. In one example, the wavelength of the maximum intensity of the UV light emitted from the light source 40 is 405nm.

[0050] like Figure 2As shown, the optical modulator 50 of the optical forming device 100 is disposed between the resin tank 10 and the light source 40. The optical modulator 50 modulates the curing light emitted from the light source 40 in a pattern based on the shape of the three-dimensional object Ob, and irradiates the modulated curing light onto the photocurable resin RL through the bottom 12 of the resin tank 10. Figure 3 As shown, the optical modulator 50 includes modulation areas 52 arranged in a matrix and modulating the curing light. The optical modulator 50 is a lateral electric field driven liquid crystal panel driven by a thin film transistor (TFT). In this embodiment, the optical modulator 50 operates in an in-plane switching mode. Note that Figure 3 Only a portion of the plurality of modulation regions 52 is shown.

[0051] like Figure 3 As shown, the optical modulator 50 includes a TFT substrate 60, an opposing substrate 70, and a driver IC 85. Figure 4 As shown, the optical modulator 50 includes a liquid crystal 62 , a first electrode 64 , a second electrode 66 , a first polarizing plate 72 , and a second polarizing plate 74 .

[0052] First, the TFT substrate 60 , the counter substrate 70 , the first polarizing plate 72 , the second polarizing plate 74 , and the driver IC 85 are described.

[0053] like Figure 3 As shown, the TFT substrate 60 of the optical modulator 50 includes a first substrate 61 and a driver circuit 82. In one example, the first substrate 61 is implemented as a glass substrate. Figure 4 As shown, a first electrode 64 and a second electrode 66 for applying voltage to the liquid crystal 62 are provided on the first major surface 61a of the first substrate 61. A first polarizing plate 72 is provided on the second major surface 61b of the first substrate 61.

[0054] On the first main surface 61a of the first substrate 61, there are provided TFTs for selecting the modulation area 52, a light shielding film for protecting the TFTs from the influence of curing light, an alignment film for aligning the liquid crystal 62, etc. (not all shown in the figure). In addition, a plurality of common lines, a plurality of signal lines, and a plurality of scan lines (not all shown in the figure) are formed on the first main surface 61a of the first substrate 61. The common lines supply a common potential to the first electrode 64. The signal lines supply a voltage to the second electrode 66, and the scan lines supply a voltage for operating the TFTs. The modulation area 52 is surrounded by the signal lines and the scan lines. The TFTs are arranged at the intersection between the scan lines and the signal lines. The signal lines and the second electrode 66 are connected to each other via the TFTs.

[0055] like Figure 3As shown, the driver circuit 82 is provided at a position around the area in which the modulation area 52 is arranged. The driver circuit 82 supplies voltages to the scanning lines, the signal lines, and the common lines.

[0056] like Figure 4 As shown, the counter substrate 70 of the optical modulator 50 faces the TFT substrate 60 and is attached to the TFT substrate 60 via a sealing material (not shown). The counter substrate 70 includes a second substrate 71 and a black matrix BM. In one example, the second substrate 71 is implemented as a glass substrate. The black matrix BM and an alignment film for aligning the liquid crystals 62 are provided on the first major surface 71a of the second substrate 71. A second polarizing plate 74 is provided on the second major surface 71b of the second substrate 71.

[0057] Additionally, the second substrate 71 and the first substrate 61 of the TFT substrate 60 sandwich the liquid crystal 62 .

[0058] The black matrix BM is provided in a lattice shape on the first major surface 71a of the second substrate 71. The black matrix BM defines the modulation area 52. The black matrix BM is formed of a black resin, chrome, or the like.

[0059] The first polarizing plate 72 of the optical modulator 50 is provided on the second major surface 61b of the first substrate 61. The polarization axis of the first polarizing plate 72 is provided parallel to the alignment direction (+Y direction) of the liquid crystal 62.

[0060] The second polarizing plate 74 of the optical modulator 50 is provided on the second major surface 71b of the second substrate 71. The polarization axis of the second polarizing plate 74 is arranged in a cross-Nicol alignment relative to the polarization axis of the first polarizing plate 72. Therefore, the optical modulator 50 operates in a normally black mode.

[0061] A driver IC 85 of the optical modulator 50 is provided on the first substrate 61 of the TFT substrate 60. The driver IC 85 supplies power, timing signals, etc. to the driver circuit 82. The driver IC 85 is connected to the controller 90 via a flexible printed circuit (FPC) not shown.

[0062] Next, the liquid crystal 62 , the first electrode 64 , the second electrode 66 , and the modulation region 52 are described.

[0063] The liquid crystal 62 of the optical modulator 50 is sandwiched between the first substrate 61 of the TFT substrate 60 and the second substrate 71 of the counter substrate 70. When no voltage is applied, the liquid crystal 62 is aligned parallel to the first major surface 61a of the first substrate 61 by the alignment films provided on the first and second substrates 61, 71. Furthermore, due to the voltage applied by the first and second electrodes 64, 66, the liquid crystal 62 rotates within a plane parallel to the first major surface 61a of the first substrate 61. In this embodiment, the liquid crystal 62 is implemented as a positive nematic liquid crystal aligned in the +Y direction.

[0064] The first electrode 64 and the second electrode 66 of the optical modulator 50 apply a voltage to the liquid crystal 62. The first electrode 64 is connected to a common line and functions as a common electrode. The second electrode 66 is connected to a signal line via a TFT and functions as a drive electrode.

[0065] like Figure 5 As shown, the first electrode 64 and the second electrode 66 are formed on the first main surface 61a of the first substrate 61. The first electrode 64 and the second electrode 66 are formed in a comb shape by indium tin oxide (ITO). The first electrode 64 includes comb teeth 64a, 64b extending in the alignment direction (Y+ direction) of the liquid crystal 62. The comb teeth 64a, 64b are bent in a V shape. The second electrode 66 includes comb teeth 66a, 66b, 66c extending in the direction (-Y direction) opposite to the comb teeth 64a, 64b of the first electrode 64. The comb teeth 66a, 66b, 66c are bent in a V shape. The comb teeth 66a, 66b, 66c of the second electrode 66 and the comb teeth 64a, 64b of the first electrode 64 are alternately arranged parallel to each other in the X direction. Due to this configuration, a lateral electric field is generated between the comb teeth 66 a and the comb teeth 64 a, between the comb teeth 64 a and the comb teeth 66 b, between the comb teeth 66 b and the comb teeth 64 b, and between the comb teeth 64 b and the comb teeth 66 c in the X direction and parallel to the first major surface 61 a of the first substrate 61. The liquid crystal 62 rotates within a plane parallel to the first major surface 61 a of the first substrate 61 due to the lateral electric field in the X direction and parallel to the first major surface 61 a of the first substrate 61.

[0066] Details of the comb teeth 64 a , 64 b of the first electrode 64 and the comb teeth 66 a , 66 b , 66 c of the second electrode 66 are described later.

[0067] The modulation areas 52 of the optical modulator 50 are arranged in a matrix and modulate the curing light emitted from the light source 40. Figure 5 As shown, each modulation region 52 includes three regions. Figure 5 In the figure, for ease of understanding, the first polarizing plate 72 and the second polarizing plate 74 are not shown.

[0068] The first region 52a of the modulation region 52 is located on the root side (-Y direction side) of the comb teeth 64a and 64b of the first electrode 64. The second region 52b of the modulation region 52 is located on the root side (+Y direction side) of the comb teeth 66a, 66b, and 66c of the second electrode 66. The third region 52c of the modulation region 52 is located between the first region 52a and the second region 52b. The spacing between the comb teeth 64a and 64b and the comb teeth 66a to 66c is different in the first region 52a, the second region 52b, and the third region 52c. As a result, the first region 52a, the second region 52b, and the third region 52c have different voltage transmission characteristics.

[0069] By increasing the width of the comb teeth 66a, 66b, 66c, the pitch D1 of the comb teeth 66a, 64a, 66b, 64b, 66c in the first region 52a is set to be the narrowest, and the transmittance changes with the lowest voltage in the first region 52a (that is, the lowest driving voltage of the liquid crystal 62). The pitch D2 of the comb teeth 66a, 64a, 66b in the second region 52b is set to be wider than the pitch of the comb teeth 64a, 66b, 64b, 66c in the first region 52a, and the transmittance changes with a higher voltage in the second region 52b than in the first region (that is, the driving voltage of the liquid crystal 62 is higher than the driving voltage in the first region 52a). By reducing the width of the comb teeth 66a, 66b, 66c, the spacing D3 of the comb teeth 66a, 64a, 66b, 64b, 66c in the third region 52c is set to be the widest, and the transmittance changes with the highest voltage in the third region 52c (that is, the driving voltage of the liquid crystal 62 is the highest).

[0070] In the following, reference Figure 6 At the same time, a detailed description is given of the voltage transmission characteristics of the first region 52a, the second region 52b, and the third region 52c and the cured state of the photocurable resin RL. Note that the comb teeth 64b of the first electrode 64 are not provided in the second region 52b. The reason for this configuration will be described later.

[0071] The spacing between comb teeth 64a, 64b, and 66a to 66c is adjusted to set the transmittance of the first, second, and third regions 52a, 52b, and 52c to be greater than, equal to, or less than a predetermined transmittance Ts when each of the predetermined first to fourth voltages V1 to V4 is applied to the liquid crystal 62. The voltage values ​​of the various voltages increase in the order of first voltage V1, second voltage V2, third voltage V3, and fourth voltage V4. The predetermined transmittance Ts is the transmittance at which the energy per unit area of ​​the curing light irradiated on the photocurable resin RL reaches the critical exposure level of the photocurable resin RL. The phrase "critical exposure level of the photocurable resin RL" refers to the minimum energy per unit area required for the photocurable resin RL to cure. For example, the critical exposure level of urethane-acrylate photocurable resin is approximately 0.8 mJ / cm2. Therefore, when the transmittance of any region of the modulation area 52 is greater than or equal to the predetermined transmittance Ts, the photocurable resin RL corresponding to that region is cured. Additionally, when the transmittance of any region of the modulation area 52 is less than the predetermined transmittance Ts, the photocurable resin RL of the region corresponding to this region is not cured. Note that the predetermined first voltage V1 to fourth voltage V4 are referred to as "first voltage V1," "second voltage V2," "third voltage V3," and "fourth voltage V4," respectively. Additionally, the predetermined transmittance Ts is referred to as "critical transmittance Ts."

[0072] First, the first region 52a is described. Figure 6 As shown, in a first state where a minimum first voltage V1 is applied to the liquid crystal 62, the transmittance of the first region 52a is less than the critical transmittance Ts. In a second state where a second voltage V2 greater than the first voltage V1 is applied to the liquid crystal 62, the transmittance of the first region 52a is greater than or equal to the critical transmittance Ts. In a third state where a third voltage V3 greater than the second voltage V2 is applied to the liquid crystal 62, the transmittance of the first region 52a is less than the maximum transmittance but greater than or equal to the critical transmittance Ts. In a fourth state where a maximum fourth voltage V4 is applied to the liquid crystal 62, the transmittance of the first region 52a is less than the critical transmittance Ts.

[0073] Therefore, in the first state where the first voltage V1 is applied to the liquid crystal 62 and in the fourth state where the fourth voltage V4 is applied to the liquid crystal 62, the photocurable resin RL in the region corresponding to the first region 52a is not cured. However, in the second state where the second voltage V2 is applied to the liquid crystal 62 and in the third state where the third voltage V3 is applied to the liquid crystal 62, the photocurable resin RL in the region corresponding to the first region 52a is cured.

[0074] Next, the second region 52b is described. In the first state where the first voltage V1 is applied to the liquid crystal 62, the transmittance of the second region 52b is less than the critical transmittance Ts, as in the first region 52a. Figure 6As shown, in the second state where the second voltage V2 is applied to the liquid crystal 62, the transmittance of the second region 52b where the driving voltage is higher than the driving voltage in the first region 52a remains less than the critical transmittance Ts. In the third state where the third voltage V3 is applied to the liquid crystal 62, the transmittance of the second region 52b is greater than or equal to the critical transmittance Ts. In the fourth state where the fourth voltage V4 is applied to the liquid crystal 62, the transmittance of the second region 52b is less than the maximum transmittance but greater than or equal to the critical transmittance Ts.

[0075] Therefore, in the first state where the first voltage V1 is applied to the liquid crystal 62 and the second state where the second voltage V2 is applied to the liquid crystal 62, the photocurable resin RL in the region corresponding to the second region 52b is not cured. However, in the third state where the third voltage V3 is applied to the liquid crystal 62 and the fourth state where the fourth voltage V4 is applied to the liquid crystal 62, the photocurable resin RL in the region corresponding to the second region 52b is cured.

[0076] like Figure 6 As shown, when any one of the first to fourth voltages V1 to V4 is applied, the transmittance of the third region 52c where the driving voltage is the highest is less than the critical transmittance Ts. Note that the photocurable resin RL located directly above the third region 52c is included in the photocurable resin RL of the region corresponding to the first region 52a or the photocurable resin RL of the region corresponding to the second region 52b.

[0077] In summary, in a first state where the first voltage V1 is applied to the liquid crystal 62, the transmittances of the first, second, and third regions 52a, 52b, and 52c are less than the critical transmittance Ts, and thus, the photocurable resin RL corresponding to all regions is not cured. In a second state where the second voltage V2 is applied to the liquid crystal 62, the transmittance of the first region 52a is greater than or equal to the critical transmittance Ts, and the transmittances of the second and third regions 52b, 52c are less than the critical transmittance Ts, and thus, the photocurable resin RL corresponding to the first region 52a is cured. In a third state where the third voltage V3 is applied to the liquid crystal 62, the transmittances of the first and second regions 52a, 52b are greater than or equal to the critical transmittance Ts, and the transmittance of the third region 52c is less than the critical transmittance Ts, and thus, the photocurable resin RL corresponding to the first and second regions 52a, 52b is cured. In the fourth state in which the fourth voltage V4 is applied to the liquid crystal 62, the transmittances of the first region 52a and the third region 52c are less than the critical transmittance Ts, and the transmittance of the second region 52b is greater than or equal to the critical transmittance Ts, and thus, the photocurable resin RL of the region corresponding to the second region 52b is cured.

[0078] Therefore, in this embodiment, by controlling the voltage applied to the liquid crystal 62 in one modulation region 52, thereby controlling the transmittance of the two regions (first region 52a and second region 52b) within the modulation region 52, it is possible to control whether the photocurable resin RL corresponding to each region is cured. Since it is possible to control whether the photocurable resin RL corresponding to the two regions within the modulation region 52 is cured by one modulation region 52, the number of driver ICs 85 of the optical modulator 50 can be reduced. In addition, the driver circuit 82 of the optical modulator 50 can be simplified.

[0079] The transmittance of the first region 52a in the second state, the transmittance of the first region 52a in the third state, the transmittance of the second region 52b in the third state, and the transmittance of the second region 52b in the fourth state (hereinafter collectively referred to as "exposure transmittance Te") depend on the thickness of the photocurable resin RL to be cured. Specifically, the thickness of the photocurable resin RL to be cured depends on the energy per unit area of ​​the emitted curing light (hereinafter referred to as "curing exposure"), and thus, the exposure transmittance Te is set to the transmittance of the curing light having the curing exposure corresponding to the thickness of the photocurable resin RL to be cured. In one example, when the curing exposure for curing the urethane-acrylate photocurable resin at a thickness of 100 μm is 2 mJ / cm 2 When the exposure transmittance Te is set to the exposure dose of the transmitted curing light of 2mJ / cm 2 transmittance.

[0080] In this embodiment, it is preferred that the sum of the areas of the first region 52a through which the curing light is transmitted S1 and the sum of the areas of the second region 52b through which the curing light is transmitted S2 be equal. Figure 6 As shown, the exposure transmittance Te at the second voltage V2 (second state), the third voltage V3 (third state), and the fourth voltage V4 (fourth state) are set to be equal. This configuration makes it easy to control the curing exposure amount of the curing light irradiated on the photocurable resin RL and makes it possible to uniformly cure the photocurable resin RL.

[0081] like Figure 7As shown, the "area S1 of the first region 52a that transmits the curing light" refers to the region in the first region 52a where the transverse electric field is generated between the electrodes (comb teeth 64a to 64c and 66a, 66b). Additionally, the "area S2 of the second region 52b that transmits the curing light" refers to the region in the second region 52b where the transverse electric field is generated between the electrodes (comb teeth 64a, 66a, 66b). In this embodiment, the comb teeth 64b of the first electrode 64 are not provided in the second region 52b. Therefore, the sum of the areas of the regions S1 is equal to the sum of the areas of the regions S2. Figure 7 , for ease of understanding, the first polarizing plate 72, the second polarizing plate 74, etc. are not shown, and the first electrode 64 and the second electrode 66 are indicated by dotted lines.

[0082] Back to Figure 1 The controller 90 of the optical forming device 100 controls the mover 30, the light source 40, and the optical modulator 50. Furthermore, the controller 90 generates cross-sectional shape data representing the shape of a cross section of the three-dimensional object Ob perpendicular to the +Z direction based on the three-dimensional shape data representing the three-dimensional shape of the three-dimensional object Ob. The cross-sectional shape data is generated at predetermined intervals.

[0083] The controller 90 includes a central processing unit (CPU) 92 that performs various processes, a read-only memory (ROM) 94 that stores programs and data, a random access memory (RAM) 96 that stores data, and an input / output interface 98 that inputs and outputs signals to and from various components. The CPU 92 executes the programs stored in the ROM 94 to implement the functions of the controller 90. The input / output interface 98 inputs and outputs signals to and from the CPU 92, the mover 30, the light source 40, the driver IC 85 of the optical modulator 50, and external devices (not shown).

[0084] Next, refer to Figure 8 1. The method for forming the three-dimensional object Ob will be described while the method for forming the three-dimensional object Ob will be described. In this embodiment, the three-dimensional object Ob is formed by laminating n layers of cocoa light-curable resin RS that have been cured by the optical forming apparatus 100.

[0085] Figure 8is a flowchart illustrating a method for forming a three-dimensional object Ob. The method includes preparing a photocurable resin RL and cross-sectional shape data (step S10), setting the forming plate 20 in an initial position (step S20), curing the photocurable resin RL by modulating curing light and irradiating the photocurable resin RL with the modulated curing light (step S30), moving the cured photocurable resin RS (step S40), and determining whether n layers of cured photocurable resin RS have been laminated (step S50). In this embodiment, steps S30 and S40 are repeated.

[0086] In step S10, a photocurable resin RL and cross-sectional shape data of the three-dimensional object Ob are prepared for forming the three-dimensional object Ob. In this embodiment, the photocurable resin RL is implemented as a UV-curable resin. The cross-sectional shape data is generated by the controller 90 of the optical forming device 100 based on the three-dimensional shape data of the three-dimensional object Ob input from an external device. N layers of cross-sectional shape data are generated. In one example, the three-dimensional shape data is three-dimensional computer-aided design (CAD) data of the three-dimensional object Ob.

[0087] In step S20, the forming plate 20 is moved by the mover 30 to be placed in the initial position. Specifically, the forming plate 20 is placed in a position where the distance between the surface 20a on which the three-dimensional object Ob is formed and the bottom 12 of the resin tank 10 is the thickness of one layer of cured photocurable resin RS.

[0088] In step S30, UV light is emitted from light source 40. Based on the cross-sectional shape data of the first layer, the emitted UV light is modulated by optical modulator 50. The modulated UV light irradiates the photocurable resin RL through bottom 12 of resin tank 10. As a result, the photocurable resin RL is cured to form a first layer of cured photocurable resin RS.

[0089] In the optical modulator 50, by controlling the voltage applied to the liquid crystal 62 of the selected modulation area 52, it is possible to control whether the photocurable resin RL corresponding to the two regions (the first region 52a and the second region 52b) in one modulation area 52 is cured. Thus, the photocurable resin RS can be formed with a simple structure.

[0090] In step S40 , the mover 30 moves the cured photocurable resin RS (forming plate 20 ) in the +Z direction by an amount corresponding to the thickness of the layer of cured photocurable resin RS.

[0091] In step S50, if step S30 has been executed less than n times, it is determined that n layers of cured photocurable resin RS have not been laminated (step S50: No). If it is determined that n layers have not been laminated, step S30 of the forming process is executed, and a second or subsequent layer of cured photocurable resin RS is formed. If step S30 has been executed n times, it is determined that n layers of cured photocurable resin rRS have been laminated (step S50: Yes), and the forming process ends. Thus, the optical forming apparatus 100 can form the three-dimensional object Ob.

[0092] As described above, because the comb teeth 64a, 64b of the first electrode 64 and the comb teeth 66a, 66b, 66c of the second electrode 66 have different pitches, the first region 52a and the second region 52b of the modulation region 52 of the optical modulator 50 have different voltage-transmittance characteristics. Specifically, in a first state in which a first voltage V1 is applied to the liquid crystal 62, the first region 52a and the second region 52b have a transmittance less than the critical transmittance Ts. In a second state in which a second voltage V2 is applied to the liquid crystal 62, the first region 52a has a transmittance greater than or equal to the critical transmittance Ts, and the second region 52b has a transmittance less than the critical transmittance Ts. In a third state in which a third voltage V3 is applied to the liquid crystal 62, the first region 52a and the second region 52b have a transmittance greater than or equal to the critical transmittance Ts. In a fourth state in which a fourth voltage V4 is applied to the liquid crystal 62, the transmittance of the first region 52a is less than the critical transmittance Ts, and the transmittance of the second region 52b is greater than or equal to the critical transmittance Ts.

[0093] The transmittance of the first region 52a and the second region 52b of the modulation region 52 is controlled by a voltage applied to the liquid crystal 62, thereby making it possible to control whether the photocurable resin RL corresponding to each of the regions is cured. This reduces the number of driver ICs 85 in the optical modulator 50. Furthermore, the driver circuit 82 of the optical modulator 50 can be simplified. Consequently, the optical forming device 100 can form a wide cross-sectional area with high resolution using a simple configuration.

[0094] Example 2

[0095] In the optical forming device 100 of Example 1, the first region 52a and the second region 52b of the modulation region 52 have different voltage-transmittance characteristics due to the different pitches between the comb teeth 64a, 64b and 66a to 66c. The first region 52a and the second region 52b of the modulation region 52 may have different voltage-transmittance characteristics by other configurations.

[0096] Reference Figures 9 to 11The optical forming device 100 of this embodiment will be described while also being described. Like the optical forming device 100 of Example 1, the optical forming device 100 of this embodiment includes a resin pot 10, a forming plate 20, a mover 30, a light source 40, an optical modulator 50, and a controller 90. In this embodiment, the configurations of the first electrode 64, the second electrode 66, the first polarizing plate 72, and the second polarizing plate 74 of the optical modulator 50 differ from those of Example 1. Thus, these components and the modulation region 52 are described.

[0097] As in Example 1, the first electrode 64 and the second electrode 66 of this embodiment are formed in a comb-teeth shape on the first main surface 61a of the first substrate 61 by ITO. Figure 9 As shown, the first electrode 64 extends in the orientation direction 62a (+Y direction) of the liquid crystal 62. Additionally, the first electrode 64 includes comb teeth 64a, 64b bent in a V shape. The second electrode 66 extends in the direction (-Y direction) opposite to the comb teeth 64a, 64b of the first electrode 64. The second electrode 66 includes comb teeth 66a, 66b, 66c bent in a V shape. The comb teeth 66a, 66b, 66c of the second electrode 66 and the comb teeth 64a, 64b of the first electrode 64 are alternately arranged, equidistantly spaced and parallel to each other in the X direction. Due to this configuration, as in Example 1, a lateral electric field in the X direction and parallel to the first major surface 61a is generated between the comb teeth 66a and the comb teeth 64a, between the comb teeth 64a and the comb teeth 66b, between the comb teeth 66b and the comb teeth 64b, and between the comb teeth 64b and the comb teeth 66c. The liquid crystal 62 rotates within a plane parallel to the first major surface 61 a of the first substrate 61 due to a lateral electric field in the X direction and parallel to the first major surface 61 a .

[0098] As in Embodiment 1, the first polarizing plate 72 of this embodiment is provided on the second major surface 61b of the first substrate 61. In this embodiment, as Figure 9 As shown, the polarization axis 72 a of the first polarizing plate 72 is tilted at a tilt angle θ relative to the alignment direction 62 a (+Y direction) of the liquid crystal 62 .

[0099] As in Embodiment 1, the second polarizing plate 74 of this embodiment is provided on the second major surface 71b of the second substrate 71. As in Embodiment 1, the polarization axis 74a of the second polarizing plate 74 is arranged in a crossed Nicol alignment relative to the polarization axis 72a of the first polarizing plate 72.

[0100] In this embodiment, the comb teeth 64a, 64b of the first electrode 64 and the comb teeth 66a to 66c of the second electrode 66 are bent in a V-shape, and the polarization axis 72a of the first polarizing plate 72 is tilted relative to the alignment direction of the liquid crystal 62. As a result, a first region 52a and a second region 52b having mutually different voltage transmission characteristics are generated in each of the modulation regions 52. The first region 52a and the second region 52b are separated at the bent portion of the comb teeth 64a, 64b and 66a to 66c. The first region 52a is located on the root side (-Y direction side) of the comb teeth 64a, 64b, and the second region 52b is located on the root side (+Y direction side) of the comb teeth 66a to 66c of the second electrode 66.

[0101] Next, the voltage transmission characteristics of the first region 52 a and the second region 52 b of the present embodiment are described. Figure 10 The voltage transmission characteristics of the first region 52 a and the second region 52 b when the tilt angle θ=10° are shown.

[0102] When θ=10, Figure 10 As shown, the first region 52a of this embodiment has the same voltage-transmittance characteristics as the first region 52a of Example 1. Specifically, in a first state in which a first voltage V1 is applied to the liquid crystal 62, the transmittance of the first region 52a is less than the critical transmittance Ts. In a second state in which a second voltage V2 is applied to the liquid crystal 62, the transmittance of the first region 52a is greater than or equal to the critical transmittance Ts. In a third state in which a third voltage V3 is applied to the liquid crystal 62, the transmittance of the first region 52a is greater than or equal to the critical transmittance Ts. In a fourth state in which a fourth voltage V4 is applied to the liquid crystal 62, the transmittance of the first region 52a is less than the critical transmittance Ts.

[0103] When θ = 10, the second region 52b of this embodiment also has the same voltage-transmittance characteristics as the second region 52b of Example 1. Specifically, in a first state in which a first voltage V1 is applied to the liquid crystal 62, the transmittance of the second region 52b is less than the critical transmittance Ts. In a second state in which a second voltage V2 is applied to the liquid crystal 62, the transmittance of the second region 52b is less than the critical transmittance Ts. In a third state in which a third voltage V3 is applied to the liquid crystal 62, the transmittance of the second region 52b is greater than or equal to the critical transmittance Ts. In a fourth state in which a fourth voltage V4 is applied to the liquid crystal 62, the transmittance of the second region 52b is greater than or equal to the critical transmittance Ts.

[0104] Thus, as in Example 1, in this embodiment, by controlling the voltage applied to the liquid crystal 62 of one modulation region 52, the transmittance of the first region 52a and the second region 52b within the modulation region 52 can be controlled, and thus whether the photocurable resin RL corresponding to each region is cured can be controlled. Since whether the photocurable resin RL corresponding to the first region 52a and the second region 52b within the modulation region 52 is cured can be controlled by the voltage applied to the liquid crystal 62, the number of driver ICs 85 of the optical modulator 50 can be reduced. In addition, the driver circuit 82 of the optical modulator 50 can be simplified.

[0105] Figure 11 The voltage transmission characteristics of the first region 52a and the second region 52b when the tilt angle θ=15° are shown. Figure 11 As shown, the first region 52a of this embodiment has the same voltage transmission characteristics as the first region 52a of Example 1. The second region 52b of this embodiment also has the same voltage transmission characteristics as the second region 52b of Example 1. However, as Figure 11 As shown, it is difficult to increase the ratio of exposure transmittance Te to critical transmittance Ts (Te / Ts). When the ratio of exposure transmittance Te to critical transmittance Ts is small, it is impossible to increase the thickness of the cured photocurable resin RL. Therefore, it is preferable that the tilt angle θ is greater than 0° and less than 15°.

[0106] As described above, in this embodiment, the number of driver ICs 85 of the optical modulator 50 can be reduced and the driver circuit 82 of the optical modulator 50 can be simplified. Therefore, the optical forming apparatus 100 of this embodiment can form a forming object having a wide cross-sectional area with high resolution using a simple configuration.

[0107] Modified example

[0108] The embodiments have been described, but various modifications can be made to the present disclosure without departing from the spirit and scope of the present disclosure.

[0109] For example, in Example 1, the polarization axis 72a of the first polarizing plate 72 is arranged parallel to the alignment direction 62a (+Y direction) of the liquid crystal 62, and the polarization axis 74a of the second polarizing plate 74 is arranged in a cross Nicol alignment with respect to the polarization axis 72a of the first polarizing plate 72. However, similar to the polarization axis 72a of Example 2, a configuration is possible in which the polarization axis 72a of the first polarizing plate 72 of Example 1 is tilted at an inclination angle θ with respect to the alignment direction 62a of the liquid crystal 62. For example, as Figure 12As shown, such a configuration is possible, in which the comb teeth 64a, 64b of the first electrode 64 are tilted 5° (tilt angle 20) in the clockwise direction relative to the alignment direction 62a of the liquid crystal 62. ), the comb teeth 66a to 66c of the second electrode 66 are tilted 5° in the counterclockwise direction (tilt angle ), and the polarization axis 72a of the first polarizing plate 72 is tilted 5° in the clockwise direction (tilt angle θ=5°). In this case, as Figure 13 As shown, the ratio of the exposure transmittance Te to the critical transmittance Ts can be increased.

[0110] A configuration is possible in which the comb teeth 64a, 64b, and 66a to 66c of Embodiment 1 are not bent. Additionally, a configuration is possible in which the third region 52c of Embodiment 1 is covered with the black matrix BM of the counter substrate 70.

[0111] The bottom 12 of the resin tank 10 of Example 1 is formed of flat glass, but a configuration is possible in which the bottom 12 of the resin tank 10 can be formed of a resin that transmits curing light, a polymer film that transmits curing light, or the like. Alternatively, a configuration is possible in which the bottom 12 formed of glass, resin, or the like is subjected to a release treatment (e.g., a silicon coating treatment). With this configuration, it is possible to prevent the cured light-curable resin RS from adhering to the bottom 12.

[0112] The photocurable resin RL is not limited to UV curable resins. For example, a configuration in which the photocurable resin RL is a resin that cures by irradiation with visible light is possible. Additionally, a configuration in which the photocurable resin RL includes a polymerization inhibitor, metal particles, a pigment, etc. is possible.

[0113] The light emitted from the light source 40 is not limited to UV light. The light source 40 emits light (curing light) that cures the photocurable resin RL. A configuration is possible in which the light source 40 emits visible light according to the wavelength at which a polymerization inhibitor included in the photocurable resin RL generates an active substance. Alternatively, a configuration is possible in which the light source 40 includes a lamp instead of an LED. Furthermore, a configuration is possible in which the light source 40 includes a collimator that converts the curing light into parallel light.

[0114] In Examples 1 and 2, the first polarizing plate 72 and the second polarizing plate 74 are arranged in a cross-Nicol alignment, and the optical modulator 50 is operated in a normally black mode. However, a configuration in which the first polarizing plate 72 and the second polarizing plate 74 are arranged in a parallel Nicol alignment and the optical modulator 50 is operated in a normally white mode is possible. Additionally, the optical modulator 50 of Examples 1 and 2 operates in an in-plane switching mode, but a configuration in which the optical modulator 50 operates in other transverse electric field modes is possible. For example, a configuration in which the optical modulator 50 operates in a fringe field switching mode is possible.

[0115] In Example 1, the optical forming device 100 sequentially stacks layers of cured photocurable resin RS to form the three-dimensional object Ob. However, a configuration is possible in which the optical forming device 100 continuously irradiates the photocurable resin RL with curing light through the optical modulator 50 while continuously moving the forming plate 20 to continuously form the three-dimensional object Ob.

[0116] The optical modulator 50 of Examples 1 and 2 and the modified examples can be configured as an optical modulation device that modulates incident light and emits the modulated light. For example, a configuration in which the optical modulator 50 is used as an optical modulation device (display device) that displays characters, images, etc. is possible.

[0117] For purposes of illustration, some exemplary embodiments have been described above. Although the foregoing discussion has presented specific embodiments, those skilled in the art will recognize that changes in form and detail may be made without departing from the broader spirit and scope of the present invention. Accordingly, the specification and drawings are to be viewed in an illustrative rather than a restrictive sense. This detailed description is therefore not to be construed in a limiting sense, and the scope of the present invention is to be limited only by the claims included therein and the full scope of equivalents to which such claims are entitled.

Claims

1. An optical forming device comprising: a resin tank containing a light-curable resin; a light source emitting light for curing the photocurable resin; An optical modulator including a liquid crystal, a first substrate and a second substrate sandwiching the liquid crystal, and a first electrode and a second electrode applying a voltage to the liquid crystal; modulating light in a pattern based on the shape of the three-dimensional shaped object; and irradiating the modulated light onto the photocurable resin; a first polarizing plate provided on the first substrate, and A second polarizing plate is provided on the second substrate and is arranged in a crossed Nicol alignment relative to the first polarizing plate, wherein The optical modulator includes a plurality of modulation regions including a first region and a second region having mutually different voltage transmission characteristics. The liquid crystal is aligned in a direction parallel to the main surface of the first substrate, and the first electrode and the second electrode apply a voltage to the liquid crystal to rotate the liquid crystal in a plane parallel to the main surface of the first substrate, In a first state where a predetermined first voltage is applied to the liquid crystal, the first region and the second region have a transmittance lower than a predetermined transmittance, In a second state in which a predetermined second voltage is applied to the liquid crystal, the first region has a transmittance greater than or equal to the predetermined transmittance, and the second region has a transmittance lower than the predetermined transmittance, In a third state in which a predetermined third voltage is applied to the liquid crystal, the first region and the second region have a transmittance greater than or equal to the predetermined transmittance, In a fourth state in which a predetermined fourth voltage is applied to the liquid crystal, the first region has a transmittance less than the predetermined transmittance, and the second region has a transmittance greater than or equal to the predetermined transmittance, When the transmittance of the first region or the second region is greater than or equal to the predetermined transmittance, the photocurable resin is cured. The first electrode and the second electrode have a comb-teeth shape, When the optical modulator is viewed from above, the comb teeth of the first electrode and the comb teeth of the second electrode are alternately arranged parallel to each other. When the optical modulator is viewed from above, a distance between the comb teeth of the first electrode and the comb teeth of the second electrode in the first region is narrower than a distance between the comb teeth of the first electrode and the comb teeth of the second electrode in the second region. The comb teeth of the first electrode extend in the alignment direction of the liquid crystal and are bent in a V shape. The comb teeth of the second electrode extend in a direction opposite to the comb teeth of the first electrode and are bent in a V-shape, The comb teeth of the first electrode and the comb teeth of the second electrode in the first region are tilted 5° relative to the alignment direction of the liquid crystal. The comb teeth of the first electrode and the comb teeth of the second electrode in the second region are tilted 5° opposite to the comb teeth of the first electrode and the comb teeth of the second electrode in the first region, and One of the polarization axes of the first polarizing plate and the second polarizing plate is tilted 5° with respect to the alignment direction of the liquid crystal in the same direction as the comb teeth of the first electrode and the second electrode in the first region.

2. An optical forming device comprising: a resin tank containing a light-curable resin; a light source emitting light for curing the photocurable resin; An optical modulator including a liquid crystal, a first substrate and a second substrate sandwiching the liquid crystal, and a first electrode and a second electrode applying a voltage to the liquid crystal; modulating light in a pattern based on the shape of the three-dimensional shaped object; and irradiating the modulated light onto the photocurable resin; a first polarizing plate provided on the first substrate, and A second polarizing plate is provided on the second substrate, wherein The optical modulator includes a plurality of modulation regions including a first region and a second region having mutually different voltage transmission characteristics. The liquid crystal is aligned in a direction parallel to the main surface of the first substrate, and the first electrode and the second electrode apply a voltage to the liquid crystal to rotate the liquid crystal in a plane parallel to the main surface of the first substrate, In a first state where a predetermined first voltage is applied to the liquid crystal, the first region and the second region have a transmittance lower than a predetermined transmittance, In a second state in which a predetermined second voltage is applied to the liquid crystal, the first region has a transmittance greater than or equal to the predetermined transmittance, and the second region has a transmittance lower than the predetermined transmittance, In a third state in which a predetermined third voltage is applied to the liquid crystal, the first region and the second region have a transmittance greater than or equal to the predetermined transmittance, In a fourth state in which a predetermined fourth voltage is applied to the liquid crystal, the first region has a transmittance less than the predetermined transmittance, and the second region has a transmittance greater than or equal to the predetermined transmittance, When the transmittance of the first region or the second region is greater than or equal to the predetermined transmittance, the photocurable resin is cured. The first electrode and the second electrode have a comb-teeth shape, When the optical modulator is viewed from above, the comb teeth of the first electrode and the comb teeth of the second electrode are alternately arranged parallel to each other. The comb teeth of the first electrode and the comb teeth of the second electrode are bent in a V shape, and One of the polarization axis of the first polarizing plate and the polarization axis of the second polarizing plate is tilted by more than 0° and less than 15° relative to the alignment direction of the liquid crystal. 3 . The optical forming device according to claim 1 , wherein an area of ​​the first region through which the light is transmitted is equal to an area of ​​the second region through which the light is transmitted.

4. The optical forming device according to claim 1 or 2, wherein the transmittance of the first area in the second state, the transmittances of the first area and the second area in the third state, and the transmittance of the second area in the fourth state are equal.

5. An optical forming device according to claim 2, wherein when the optical modulator is observed from above, the spacing between the comb teeth of the first electrode and the comb teeth of the second electrode in the first area is narrower than the spacing between the comb teeth of the first electrode and the comb teeth of the second electrode in the second area.

6. An optical modulation device, comprising: a plurality of modulation regions including a first region and a second region having mutually different voltage-transmission characteristics and modulating incident light; liquid crystal, a first substrate and a second substrate sandwiching the liquid crystal, and a first electrode and a second electrode applying a voltage to the liquid crystal; a first polarizing plate provided on the first substrate, and A second polarizing plate is provided on the second substrate and is arranged in a crossed Nicol alignment relative to the first polarizing plate, wherein The liquid crystal is aligned in a direction parallel to the main surface of the first substrate, and the first electrode and the second electrode apply a voltage to the liquid crystal to rotate the liquid crystal in a plane parallel to the main surface of the first substrate, In a first state where a predetermined first voltage is applied to the liquid crystal, the first region and the second region have a transmittance lower than a predetermined transmittance, In a second state in which a predetermined second voltage is applied to the liquid crystal, the first region has a transmittance greater than or equal to the predetermined transmittance, and the second region has a transmittance lower than the predetermined transmittance, In a third state in which a predetermined third voltage is applied to the liquid crystal, the first region and the second region have a transmittance greater than or equal to the predetermined transmittance, In a fourth state in which a predetermined fourth voltage is applied to the liquid crystal, the first region has a transmittance less than the predetermined transmittance, and the second region has a transmittance greater than or equal to the predetermined transmittance, The first electrode and the second electrode have a comb-teeth shape, When the optical modulator is viewed from above, the comb teeth of the first electrode and the comb teeth of the second electrode are alternately arranged parallel to each other. When the optical modulator is viewed from above, a distance between the comb teeth of the first electrode and the comb teeth of the second electrode in the first region is narrower than a distance between the comb teeth of the first electrode and the comb teeth of the second electrode in the second region. The comb teeth of the first electrode extend in the alignment direction of the liquid crystal and are bent in a V shape. The comb teeth of the second electrode extend in a direction opposite to the comb teeth of the first electrode and are bent in a V-shape, The comb teeth of the first electrode and the comb teeth of the second electrode in the first region are tilted 5° relative to the alignment direction of the liquid crystal. The comb teeth of the first electrode and the comb teeth of the second electrode in the second region are tilted 5° opposite to the comb teeth of the first electrode and the comb teeth of the second electrode in the first region, and One of the polarization axes of the first polarizing plate and the second polarizing plate is tilted 5° with respect to the alignment direction of the liquid crystal in the same direction as the comb teeth of the first electrode and the second electrode in the first region.

7. An optical modulation device, comprising: a plurality of modulation regions including a first region and a second region having mutually different voltage-transmission characteristics and modulating incident light; liquid crystal, a first substrate and a second substrate sandwiching the liquid crystal, and a first electrode and a second electrode applying a voltage to the liquid crystal; a first polarizing plate provided on the first substrate, and A second polarizing plate is provided on the second substrate, wherein The liquid crystal is aligned in a direction parallel to the main surface of the first substrate, and the first electrode and the second electrode apply a voltage to the liquid crystal to rotate the liquid crystal in a plane parallel to the main surface of the first substrate, In a first state where a predetermined first voltage is applied to the liquid crystal, the first region and the second region have a transmittance lower than a predetermined transmittance, In a second state in which a predetermined second voltage is applied to the liquid crystal, the first region has a transmittance greater than or equal to the predetermined transmittance, and the second region has a transmittance lower than the predetermined transmittance, In a third state in which a predetermined third voltage is applied to the liquid crystal, the first region and the second region have a transmittance greater than or equal to the predetermined transmittance, In a fourth state in which a predetermined fourth voltage is applied to the liquid crystal, the first region has a transmittance less than the predetermined transmittance, and the second region has a transmittance greater than or equal to the predetermined transmittance, The first electrode and the second electrode have a comb-teeth shape, When the optical modulator is viewed from above, the comb teeth of the first electrode and the comb teeth of the second electrode are alternately arranged parallel to each other. The comb teeth of the first electrode and the comb teeth of the second electrode are bent in a V shape, and One of the polarization axis of the first polarizing plate and the polarization axis of the second polarizing plate is tilted by more than 0° and less than 15° relative to the alignment direction of the liquid crystal.

Images