Lighting device

Abstract

To provide an illumination device capable of switching the intensity distribution of emitted light with a simple structure. The illumination device includes a light source, a polarization control mechanism that switches the light emitted from the light source into light of two or more different polarization states and causes it to be incident on a polarizing plate, and the polarizing plate, which is one or more of polarizing plates having two or more regions with different polarization states of transmitted light in the in-plane direction and periodically arranging the regions and functions as a diffraction grating, thereby solving the problem.

Description

Technical Field

[0001] This invention relates to an illumination device capable of switching the intensity distribution of emitted light. Background Technology

[0002] As a method for enabling automated vehicle operation, a ranging method using a technology called LiDAR (Light Detection and Ranging) is known.

[0003] This ranging method is called TOF (Time of Flight). For example, a laser beam is emitted in pulses from a laser source, and the laser beam reflected by an object is measured using a light-receiving element. The phase shift is detected based on the time from the emission of the laser beam from the laser source to the reception of light by the light-receiving element, thereby determining the distance to the object. Furthermore, the position of the object can also be detected by scanning the laser beam in two or three dimensions.

[0004] On the other hand, two-dimensional point light sources, known as structured light, which consist of multiple points of light emitted in a two-dimensional arrangement, are used for applications such as facial authentication and gesture recognition. For example, two-dimensional point light sources are used in mobile electronic devices such as smartphones for user facial authentication.

[0005] In authentication and other applications using two-dimensional point light sources, a two-dimensional array of point lights is projected onto the object being measured, and the reflected light from the object is received by a light-receiving element. Based on the changes in the spacing and dot pattern of the received point lights relative to the irradiated point lights, the distance to the object and the surface irregularities of the object are detected, enabling facial authentication and other applications.

[0006] Therefore, if a single light source emitting a beam of light and a two-dimensional point light source emitting a beam of light composed of multiple points arranged in two dimensions can be switched in order to perform TOF-based ranging, then the ranging of the object, position detection, and three-dimensional shape recognition of the object can be performed simultaneously and accurately.

[0007] Correspondingly, Patent Document 1 describes a liquid crystal diffraction grating comprising: a pair of substrates, each having electrodes; a liquid crystal layer disposed between the pair of substrates and containing liquid crystal material; a sealing material surrounding the liquid crystal layer; and an alignment control layer disposed in the area surrounded by the sealing material and configured to contact the liquid crystal layer between one or both of the pair of substrates and the liquid crystal layer. The alignment control layer aligns the liquid crystal molecules in the liquid crystal material in a horizontal direction relative to the pair of substrates and contains a polymer formed by polymerizing at least one monomer. When the liquid crystal layer is viewed from above in a horizontally aligned state with the liquid crystal molecules aligned in a horizontal direction relative to the pair of substrates, the alignment direction of the liquid crystal molecules rotates periodically in at least one direction. A diffraction state and a transparent state can be switched by applying a voltage to a pair of electrodes of the pair of substrates.

[0008] Previous technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-56825 Summary of the Invention

[0011] The technical problem to be solved by the invention

[0012] As described in Patent Document 1, according to this liquid crystal diffraction element, when light is incident on the liquid crystal diffraction element, the voltage applied to the counter electrode is switched to switch the liquid crystal layer to a transparent state and a diffraction state, thereby enabling the switching between a single light source and a two-dimensional point light source.

[0013] However, the liquid crystal diffraction element described in Patent Document 1 requires patterning the liquid crystal layer (liquid crystal cell) so that the orientation of the liquid crystal molecules changes at predetermined angles and rotates periodically. Therefore, the structure of this liquid crystal diffraction element is complex and its manufacturing is cumbersome.

[0014] The purpose of this invention is to solve the problems of the prior art and provide a simple lighting device, for example, capable of switching the intensity distribution of emitted light from a single light source and a two-dimensional point light source.

[0015] means for solving technical problems

[0016] To solve this problem, the lighting device of the present invention has the following structure.

[0017] [1] A lighting device comprising a light source, a polarization control mechanism, and a polarizer,

[0018] The polarization control mechanism switches the light emitted from the light source into at least two different polarization states and directs it onto the polarizer.

[0019] A polarizer is a polarizer that has two or more regions in the in-plane direction with different polarization states of transmitted light and one or more regions arranged periodically, and functions as a diffraction grating.

[0020] [2] According to the lighting device described in [1], wherein,

[0021] A polarizer has two or more regions with different absorption axes.

[0022] [3] The lighting device according to [1] or [2], wherein,

[0023] The polarization control mechanism is positioned closer to the light source than the polarizer, and from the light source side, there are a polarizer and a liquid crystal unit in sequence.

[0024] [4] The lighting device according to any one of [1] to [3], wherein,

[0025] One or more regions of the polarizer contain dichroic material.

[0026] [5] According to the lighting device described in [4], wherein,

[0027] One or more of the regions containing dichroic substances are regions in which the dichroic substances are horizontally oriented.

[0028] [6] The lighting device according to [4] or [5], wherein,

[0029] One or more of the regions containing dichroic substances are regions in which the dichroic substances are oriented vertically.

[0030] Invention Effects

[0031] According to the present invention, a simple lighting device (light irradiation device) capable of switching the intensity distribution of emitted light can be provided. Attached Figure Description

[0032] Figure 1 This is a diagram that conceptually illustrates an example of the lighting device of the present invention.

[0033] Figure 2 This is a diagram that conceptually represents an example of a liquid crystal cell.

[0034] Figure 3 This is a diagram that conceptually represents an example of a polarizer (diffraction grating).

[0035] Figure 4 It is used for explanation Figure 1 A conceptual diagram illustrating the function of the lighting device shown.

[0036] Figure 5 It is used for explanation Figure 1A conceptual diagram illustrating the function of the lighting device shown. Detailed Implementation

[0037] Hereinafter, the lighting device of the present invention will be described in detail with reference to the preferred embodiment shown in the accompanying drawings.

[0038] In this specification, the numerical range indicated by “~” refers to the range encompassed by the values ​​recorded before and after “~” as the lower and upper limits.

[0039] In this specification, "(meth)acrylate" is used to mean "one or both of acrylate and methacrylate".

[0040] In this specification, "same" includes the range of error generally permissible in the art. Furthermore, in this specification, "all," "uniform," and "the entire surface," except for the case of 100%, include the range of error generally permissible in the art, including, for example, 99% or more, 95% or more, or 90% or more.

[0041] Figure 1 The present invention is conceptually illustrated as an example of a lighting device.

[0042] Figure 1 The lighting device 10 shown includes a light source 12, a polarizer 14, a liquid crystal unit 16, and a polarizer 18. The polarizer 14 and the liquid crystal unit 16 constitute the polarization control mechanism of the present invention, and the polarizer 14 and the liquid crystal unit 16 are arranged sequentially from the light source 12.

[0043] The polarizer 14 and the liquid crystal unit 16, i.e., the polarization control mechanism, switch the light emitted from the light source 12 into at least two different polarization states and direct it onto the polarizer 18. In the example shown, the polarizer 14 and the liquid crystal unit 16 switch the light emitted from the light source 12 into either of two mutually orthogonal linearly polarized lights and direct it onto the polarizer 18.

[0044] Furthermore, the polarizer 18 is a polarizer that has two or more regions with different polarization states of transmitted light in the plane and periodically arranges one or more of these regions, and functions as a diffraction grating (diffraction element). In the example shown, the polarizer 18 has a periodic structure like a checkerboard pattern, wherein a first region 18a, in which the dichroic material is horizontally oriented in one direction, and a second region 18b, in which the dichroic material is vertically oriented, are alternately arranged in two dimensions in the plane (plane direction) along orthogonal directions.

[0045] In the following description, in order to distinguish between the polarizer 14 and the polarizer 18 that constitute the polarization control mechanism, the polarizer 18 will also be referred to as the diffraction grating polarizer 18.

[0046] In the lighting device 10 of the present invention, the polarization state of light incident on the diffraction grating polarizer 18 is switched by the liquid crystal unit 16. The lighting device 10 of the present invention switches the polarization state of the incident light to the diffraction grating polarizer 18, such as... Figure 1 As shown in the lower section, it can be switched between a single light source emitting a beam of light from the left and a two-dimensional point light source emitting multiple point-like lights arranged in two dimensions from the right.

[0047] This viewpoint will be discussed in detail later.

[0048] In the lighting device 10 of the present invention, there is no limitation on the light source 12, and various known light sources can be used.

[0049] As a light source 12, examples include light bulbs such as mercury lamps and halogen lamps, fluorescent lamps, and lasers such as LEDs (Light Emitting Diodes) and semiconductor lasers.

[0050] Among them, LEDs and semiconductor lasers are preferred.

[0051] There are no restrictions on the wavelength of the light emitted by the light source 12; it can be visible light, or non-visible light such as infrared or ultraviolet light. When the light emitted by the light source 12 is visible light, the emitted light can be white light, red light, green light, or blue light. Infrared light is preferred for use as the light emitted by the light source 12.

[0052] Furthermore, the light emitted by the light source 12 can be either unpolarized or polarized. In the lighting device 10 illustrated in the figure, the light source 12, as an example, emits unpolarized light.

[0053] In the lighting device 10 of the present invention, the light source 12 preferably emits light with high directionality.

[0054] Specifically, the light source 12 preferably emits light with a beam divergence angle of 15° or less, more preferably light with a beam divergence angle of 5° or less, even more preferably light with a beam divergence angle of 3° or less, and especially preferably parallel light (collimated light).

[0055] Additionally, the beam divergence angle refers to the angle from the maximum radiation intensity of the light emitted from the light source to half the maximum radiation intensity (half-width at half maximum).

[0056] The lighting device 10 functions as both a single light source and a two-dimensional point light source by using a polarization control mechanism and a diffraction grating polarizer 18 that acts as a diffraction grating. In such a lighting device 10, the higher the directivity of the light emitted from the light source 12, the clearer the two-dimensional point light (dot pattern) is obtained.

[0057] In addition, when the directivity of the light emitted by the light source 12 is low, a lens element that collects the light emitted by the light source 12 to improve the directivity of the light can be arranged between the light source 12 and the polarization control mechanism.

[0058] There are no limitations on the lens element; various optical elements capable of collecting diffused light and bringing it close to parallel light can be used. Specifically, examples of lens elements include convex lenses, collimating lenses, and beam collimators.

[0059] The light emitted from the light source 12 first enters the polarizer 14 and becomes linearly polarized light in one direction.

[0060] In the example shown, polarizer 14 causes the light emitted from light source 12 to be linearly polarized in the same direction as the horizontal orientation of the dichroic material in the first region 18a of the diffraction grating polarizer 18, which will be described later.

[0061] As long as the polarizer 14 can make the light into a specific linearly polarized light, a known polarizer (linear polarizer) can be used. Therefore, the polarizer 14 can be either an absorption type or a reflection type.

[0062] Examples of polarizers 14 include iodine-based polarizers, pigment-based polarizers utilizing dichroic pigments, polyene-based polarizers, thin films formed by stretching dielectric multilayer films, wire grid polarizers, and prism-type polarizers. For example, examples of general absorption-type linear polarizers include the polarizer 02 (iodine-based polarizer) with a single-sided protective film described in International Publication No. 2015 / 166991, and the organic dichroic pigment-based polarizer described in Japanese Patent Application Publication No. 2019-120949.

[0063] The linearly polarized light from the transmission polarizer 14 is then incident on the liquid crystal cell 16.

[0064] The liquid crystal cell 16 is a known liquid crystal cell in which a liquid crystal layer is disposed between a substrate with electrodes (full-surface electrodes) having a uniform surface morphology, and a birefringence change is induced by applying a voltage to the electrodes. The liquid crystal cell 16 in the figure example is formed by uniformly aligning a liquid crystal compound without an alignment pattern of the liquid crystal compound in the liquid crystal layer, and a uniform birefringence change is induced across the entire surface of the cell by applying a voltage.

[0065] The liquid crystal cell 16 uses this birefringence change to change the polarization state of the linearly polarized light of the transmission polarizer 14 as needed, and switches the transmitted linearly polarized light into two polarization states with different polarization states.

[0066] In the lighting device 10 shown in the figure, the liquid crystal unit 16 switches between a state in which the linearly polarized light emitted from the polarizer 14 is directly transmitted and a state in which the linearly polarized light emitted from the polarizer 14 is rotated by 90° and transmitted as a λ / 2 waveplate.

[0067] That is, the liquid crystal cell 16 (polarization control mechanism) switches the transmitted light, i.e. the light incident on the diffraction grating polarizer 18, into linearly polarized light that is in the same direction as the horizontal orientation of the dichroic material in the first region 18a of the diffraction grating polarizer 18 and linearly polarized light that is orthogonal to the linearly polarized light.

[0068] As long as the liquid crystal cell 16 exhibits the above-described effects, it can utilize various known materials. As a preferred example, it can be illustrated as follows: Figure 2 The liquid crystal unit 100 shown.

[0069] Figure 2 The liquid crystal unit 100 shown is configured to have a pair of substrates, namely a first substrate 110 and a second substrate 120, and a liquid crystal layer 130 held between the pair of substrates. The liquid crystal unit 100 does not have a pixel structure.

[0070] More specifically, the first substrate 110 is formed using an insulating substrate 111 that is transparent, such as glass. The first substrate 110 has a first common electrode 113 and an alignment film 114, etc., on one main surface of the insulating substrate 111.

[0071] The first common electrode 113 is a so-called full-surface electrode uniformly disposed on the entire main surface of the insulating substrate 111. This first common electrode 113 is formed, for example, from a light-transmitting conductive component such as ITO (Indium Tin Oxide). The alignment film 114 is configured to cover the entire main surface of the insulating substrate 111 and is formed from a light-transmitting material.

[0072] In addition, the main surface is the largest surface of the sheet-like material (plate-like material, film, layer), that is, the two sides in the thickness direction.

[0073] On the other hand, the structure of the second substrate 120 is the same as that of the first substrate 110, and a second common electrode 122 and an alignment film 123 are provided on a main surface of an insulating substrate 121 that is transparent, such as glass.

[0074] Therefore, the second common electrode 122 is also uniformly disposed on the entire main surface of the insulating substrate 121, and is formed, for example, from a light-transmitting conductive component such as ITO. The alignment film 123 is also similarly configured to cover the entire main surface of the insulating substrate 121 and is formed from a light-transmitting material.

[0075] In this type of liquid crystal cell 100, the phase difference value of the liquid crystal cell when no voltage is applied can be controlled by adjusting the orientation of one alignment film and another alignment film. One alignment film is, for example, the alignment film 114 on the side of the first substrate 110, and the other alignment film is, for example, the alignment film 123 on the side of the second substrate 120.

[0076] As an example, by setting both alignment film 114 and alignment film 123 as horizontal alignment films and arranging their alignment directions in parallel, a liquid crystal cell with uniformly aligned liquid crystal molecules can be formed.

[0077] Furthermore, in the liquid crystal cell 100, when a low level of voltage Va (e.g., 0V) is applied to the liquid crystal layer 130, the liquid crystal molecules 131 are arranged in a bent configuration. Therefore, the liquid crystal layer 130 has a retardation amount Rea in the in-plane direction and a retardation amount Rtha in the thickness direction.

[0078] In contrast, when a higher voltage Vb (Va < Vb) is applied to the liquid crystal layer 130, the liquid crystal molecules 131 are aligned approximately perpendicularly to the substrate, except near the alignment film 123. Therefore, the effect of retardation of the liquid crystal layer 130 based on the liquid crystal molecules 131 in the in-plane direction is mitigated. As a result, the liquid crystal layer 130 has a retardation amount Reb (Rea > Reb), and the effect of retardation based on the liquid crystal molecules 131 in the thickness direction increases, resulting in a retardation amount Rthb (Rtha < Rthb).

[0079] Thus, by controlling the phase difference of the liquid crystal cell 100 (liquid crystal layer 130), the incident polarized light can be controlled and emitted.

[0080] In the lighting device of the present invention, the polarization control mechanism is not limited to the structure of the polarizer 14 and the liquid crystal cell 16 described above. That is, in the present invention, the polarization control mechanism can utilize various mechanisms as long as it can switch the light emitted from the light source 12 into two or more linearly polarized lights with different states and incident on the diffraction grating polarizer 18 (the polarizer in the present invention).

[0081] For example, if the light source 12 is a light source (light-emitting element) that emits linearly polarized light, the polarizer 14 is not required, and the polarization control mechanism can be formed solely by the liquid crystal unit 16.

[0082] Furthermore, as a polarization control mechanism, it is also possible to utilize the following structure: by using a polarizer (linear polarizer) and a polarizer rotation mechanism, the direction of the linearly polarized light transmitted by the polarizer is switched by rotating the polarizer around a rotation axis set at the center of the plane.

[0083] Furthermore, when linearly polarized light is emitted from the light source 12, the following structure can be used: by setting a rotation mechanism for the light source and rotating the light source around the optical axis, the direction of the linearly polarized light incident on the diffraction grating polarizer 18 can be switched.

[0084] The linearly polarized light from the transmissive liquid crystal cell 16, i.e. the polarization control mechanism, is then incident on the diffraction grating polarizer 18.

[0085] In this invention, a (diffraction grating) polarizer is a polarizer that has two or more regions in the plane with different polarization states of the transmitted light and periodically arranges one or more regions, and functions as a diffraction grating.

[0086] In the lighting fixture illustrated in the figure, such as Figure 3 As shown in the conceptual diagram, the diffraction grating polarizer 18 has a periodic structure like a checkerboard pattern (grid pattern), wherein a first region 18a in which the dichroic material is horizontally oriented in one direction and a second region 18b in which the dichroic material is vertically oriented are alternately arranged in two dimensions along orthogonal directions.

[0087] The diffraction grating polarizer 18 functions as a diffraction grating by having a periodic structure having a first region 18a and a second region 18b arranged in such a periodic manner.

[0088] Furthermore, in this invention, horizontal orientation refers to the state in which the dichroic material (the absorption axis of the dichroic material) is aligned parallel to the surface of the dichroic grating polarizer 18. However, horizontal orientation includes not only the case where it is completely parallel to the surface of the dichroic grating polarizer 18, but also an angle range of ±5° relative to the direction horizontal to the surface of the dichroic grating polarizer 18.

[0089] On the other hand, in this invention, vertical orientation refers to the state in which the dichroic material (the absorption axis of the dichroic material) is oriented in a vertical direction, i.e., orthogonal, relative to the surface of the dichroic grating polarizer 18. However, vertical orientation includes not only the case where it is completely perpendicular to the surface of the dichroic grating polarizer 18, but also an angle range of ±5° relative to the direction perpendicular to the surface of the dichroic grating polarizer 18 (the perpendicular line of the surface).

[0090] Furthermore, in this invention, the description of horizontal and vertical is not limited to dichroic materials and diffraction grating polarizers; the same applies to the positional relationship of other two materials (components).

[0091] In the following description, for ease of explanation, the orientation direction (horizontal orientation direction) of the dichroic material in the first region 18a of the diffraction grating polarizer 18 is defined as the x-direction, and the direction orthogonal to the x-direction is defined as the y-direction. Furthermore, the direction orthogonal to the xy-direction, that is, the direction perpendicular to the surface of the diffraction grating polarizer 18, is defined as the z-direction.

[0092] In the diffraction grating polarizer 18, the first region 18a is a region where the dichroic material is horizontally oriented along the x-direction. That is, the first region 18a is a region with an absorption axis in the x-direction. Therefore, when linearly polarized light in the x-direction is incident, the first region 18a absorbs and does not transmit, while when linearly polarized light in the orthogonal y-direction is incident, the first region 18a transmits.

[0093] In contrast, the second region 18b of the diffraction grating polarizer 18 is a region where the dichroic material is oriented perpendicularly. That is, the second region 18b is a region that does not have an absorption axis in the in-plane direction of the diffraction grating polarizer 18 but has an absorption axis in the perpendicular direction (z direction). Therefore, whether linearly polarized light in the x-direction is incident or linearly polarized light in the orthogonal y-direction is incident, the second region 18b does not absorb but transmits.

[0094] As described above, the diffraction grating polarizer 18 has two regions: a first region 18a that transmits linearly polarized light in the y direction and a second region 18b that transmits linearly polarized light in both the x and y directions. The polarization state of the transmitted light differs between the two regions depending on the polarization state of the incident light.

[0095] Specifically, the absorption axis refers to the direction in which transmittance is highest at a wavelength of 550 nm when the transmittance of a thin film (thin-film or sheet-like optical element) is measured by varying its tilt angle (polar angle) and tilt direction (azimuth angle) relative to the normal direction. For example, it refers to the average value along the long axis of an oriented dichroic material. The transmittance obtained by varying the tilt angle and tilt direction of the thin film relative to the normal direction can be measured, for example, using an AxoScan OPMF-1 (manufactured by Opto Science, Inc.).

[0096] As described above, in the lighting device 10, the liquid crystal unit 16, i.e. the polarization control mechanism, switches the light incident on the diffraction grating polarizer 18 into linearly polarized light in the x-direction and linearly polarized light in the y-direction.

[0097] Linearly polarized light in the x-direction is linearly polarized in the same direction as the horizontal orientation of the dichroic material in the first region 18a of the diffraction grating polarizer 18. Linearly polarized light in the y-direction is linearly polarized in a direction orthogonal to the x-direction.

[0098] When the liquid crystal cell 16 causes the light incident on the diffraction grating polarizer 18 to become linearly polarized light in the y-direction, such as Figure 4 As conceptually shown on the left, either region 18a or region 18b transmits the linearly polarized light. That is, when linearly polarized light Ly in the y-direction is incident, the diffraction grating polarizer 18 functions as a transparent plate.

[0099] The result, such as Figure 1 The left side of the lower section and Figure 5 As shown conceptually on the left, the light emitted from the diffraction grating polarizer 18, i.e. the light emitted from the illumination device 10, becomes the same beam of light emitted from the light source 12, which is a point light source.

[0100] Therefore, when the liquid crystal cell 16 makes the light incident on the diffraction grating polarizer 18 into linearly polarized light Ly in the y direction, the illumination device 10 becomes a single light source that emits a beam of light.

[0101] In contrast, when the liquid crystal cell 16 causes the light incident on the diffraction grating polarizer 18 to become linearly polarized light Lx in the x-direction, such as Figure 4 As shown conceptually on the right, the linearly polarized light is blocked in region 18a and only transmits through region 2 18b.

[0102] As described above, in the diffraction grating polarizer 18, the first region 18a and the second region 18b are arranged in an orthogonal two-dimensional direction like a checkerboard pattern.

[0103] Therefore, when linearly polarized light in the x-direction is incident, the diffraction grating polarizer 18 becomes a state having a periodic structure in which the light-blocking part and the transmission part are periodically arranged in two dimensions. As a result, when linearly polarized light Lx in the x-direction is incident, the diffraction grating polarizer 18 functions as a diffraction grating.

[0104] Specifically, linearly polarized light Lx in the x-direction is transmitted through the second region 18b, which is the transmission section. Here, when linearly polarized light in the x-direction is incident, the diffraction grating polarizer 18 has a periodic structure with alternating light-blocking sections (first region 18a) and transmission sections. Therefore, the linearly polarized light in the x-direction is diffracted when it is transmitted through the transmission section, i.e., the second region 18b.

[0105] The diffraction grating polarizer 18 is in the following state: in the linearly polarized light (diffracted light) diffracted by the transmission section, the linearly polarized light transmitted through adjacent transmission sections interferes with each other to become interference light, and then the adjacent interference light interferes with each other to form a dot pattern based on the interference light.

[0106] As a result, the light emitted from the diffraction grating polarizer 18, i.e., the light emitted from the illumination device 10, is as follows: Figure 5As shown conceptually on the right, it becomes multiple points of light arranged in a two-dimensional pattern.

[0107] Therefore, when the liquid crystal cell 16 makes the light incident on the diffraction grating polarizer 18 into linearly polarized light Lx in the x direction, the illumination device 10 becomes a two-dimensional point light source that emits point light composed of multiple points arranged in two dimensions.

[0108] Furthermore, the point light is caused by diffraction and interference. Therefore, the arrangement (point pattern) of the point light becomes a different pattern from the arrangement patterns of the light-shielding part and the light-transmitting part, namely the first region 18a and the second region 18b.

[0109] Furthermore, the arrangement of the emitted point lights can be regular or irregular. The arrangement of the first region 18a and the second region 18b corresponding to the desired arrangement of point lights can be obtained, for example, using a computer hologram.

[0110] As described above, the lighting device of the present invention comprises: a (diffraction grating) polarizer having multiple regions with different polarization states of transmitted light, with one or more regions arranged periodically, and functioning as a diffraction grating; and a polarization control mechanism that switches the light emitted from the light source into multiple different polarization states and directs it onto the polarizer. This lighting device of the present invention switches the polarization state of the light incident on the polarizer via the polarization control mechanism, thereby, as shown in the example figure, enabling switching of the intensity distribution of the emitted light, such as the emission of a beam of light and the emission of a point beam.

[0111] That is, according to the present invention, an illumination device is provided that does not require patterning of the orientation of the liquid crystal compound in the liquid crystal cell and is capable of switching the intensity distribution of emitted light with a simple structure.

[0112] As described above, the diffraction grating polarizer 18 has a structure in which a first region 18a, which aligns the dichroic material horizontally in one direction, and a second region 18b, which aligns the dichroic material vertically, are arranged in a checkerboard pattern.

[0113] As an example, this diffraction grating polarizer 18 can be fabricated by forming an alignment film on a support and then forming a light-absorbing anisotropic film using a dichroic material on that alignment film.

[0114] That is, in this example, the diffraction grating polarizer 18 is a laminate of a support, an alignment film, and an anisotropic light absorption film. Additionally, depending on the requirements, the laminate may also have a polymer film, such as a polyvinyl alcohol (PVA) film, on the surface of the support, which functions as an oxygen barrier layer and / or an anti-pigment diffusion layer.

[0115] Furthermore, in this invention, the diffraction grating polarizer 18 is not limited to this structure.

[0116] As an example, the diffraction grating polarizer 18 can also be formed by peeling off the support and alignment film from the laminate, consisting only of anisotropic light absorption film. Alternatively, the diffraction grating polarizer 18 can also be formed by peeling off the support from the laminate, consisting of an alignment film and anisotropic light absorption film. Furthermore, other support substrates can be attached to the anisotropic light absorption film after the support and alignment film have been peeled off to serve as the diffraction grating polarizer 18.

[0117] As a support, as long as it has sufficient light transmittance, it can utilize various known materials.

[0118] As an example, the support can be made of polymer films (e.g., polarizer protective films) and glass substrates. In applications requiring flexibility, polymer films and glass substrates with a thickness of 100 μm or less are preferred.

[0119] Specifically, examples of polymers constituting polymer films include, for instance, cellulose-based polymers; acrylic polymers containing acrylate polymers such as polymethyl methacrylate and polymers containing lactone rings; thermoplastic norbornene-based polymers; polycarbonate-based polymers; polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate; styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers (AS resins); polyolefin-based polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; vinyl chloride-based polymers; amide-based polymers such as nylon and aromatic polyamides; imide-based polymers; sulfone-based polymers; polyethersulfone-based polymers; polyetheretherketone-based polymers; polyphenylene sulfide-based polymers; vinylidene chloride-based polymers; vinyl alcohol-based polymers; vinyl butyral-based polymers; aromatic ester-based polymers; polyoxymethylene-based polymers; epoxy-based polymers; and polymers formed by mixing these polymers.

[0120] Among these, cellulose-based polymers, represented by triacetylcellulose, are preferred as supports. In the following description, cellulose-based polymers will also be referred to as "cellulose acylates".

[0121] Furthermore, from the viewpoint of processability and optical performance, acrylic polymers are preferred as supports.

[0122] Examples of acrylic polymers include polymethyl methacrylate or polymers containing lactone rings as described in paragraphs

[0017] to

[0107] of Japanese Patent Application Publication No. 2009-98605.

[0123] In this invention, from the viewpoint of thinning, it is also preferable to peel the transparent support off from the optical film. When using a peelable polymer film, cellulose-based polymers or polyester-based polymers are preferred.

[0124] The support is preferably transparent to the corresponding light.

[0125] Here, "transparent" as used in this invention means that the corresponding light transmittance is 60% or more. Preferably, the corresponding light transmittance is 80% or more, and more preferably 90% or more.

[0126] There are no particular limitations on the thickness of the support, but considering reasons such as enabling thinner optical laminates, it is preferably 40 μm or less. There are no particular limitations on the lower limit, but it is typically 5 μm or more.

[0127] Examples of alignment films include photoalignment films and tribological alignment films.

[0128] The preferred material is a photoalignment film. As a photoalignment film, the examples described in paragraphs

[0018] to

[0078] of International Publication No. 2020 / 179864 can be used.

[0129] More specifically, photo-alignment films include photo-alignment compounds.

[0130] Photooriented compounds are compounds that have photooriented groups.

[0131] "Photooriented group" refers to a group that has the function of photoorientation by irradiation with anisotropic light (e.g., plane-polarized light) to induce recombination or anisotropic chemical reaction. From the viewpoint of excellent orientation uniformity and good thermal or chemical stability, it is preferred to be a photoorientation group that produces at least one of dimerization and isomerization by the action of light.

[0132] As a photo-oriented group that dimers through the action of light, examples include groups having a skeleton of at least one derivative selected from the group consisting of cinnamic acid derivatives (M.Schadt et al., J.Appl.Phys., vol.31, No.7, 2155 (1992)), coumarin derivatives (M.Schadt et al., Nature., vol.381, 212 (1996)), chalcone derivatives (Ogawa Toshihiro et al., Proceedings of the Liquid Crystal Symposium, 2AB03 (1997)), maleimide derivatives, and benzophenone derivatives (YKJang et al., SID Int. Symposium Digest, P-53 (1997)).

[0133] On the other hand, as photo-oriented groups that are isomerized by the action of light, examples include those having azobenzene compounds (K. Ichimura et al., Mol. Cryst. Liq. Cryst., 298, 221 (1997)), oxenyl compounds (JG Victor and JMTorkelson, Macromolecules, 20, 2241 (1987)), spiropyran compounds (K. Ichimura et al., Chemistry Letters, p. 1063 (1992); K. Ichimura et al., ThinSolid Films, vol. 235, p. 101 (1993)), cinnamic acid compounds (K. Ichimura et al., Macromolecules, 30, 903 (1997)), and hydrazine-β-keto ester compounds (S. Yamamura et al.). The group comprising the skeleton of at least one compound in the group (al., LiquidCrystals, vol.13, No.2, 189 (1993)).

[0134] As a method for manufacturing a photoalignment film, the following method can be cited: coating a photoalignment film coating liquid containing the above-mentioned photoalignment compound, and irradiating the formed coating film with polarized light or irradiating it with unpolarized light from a direction inclined relative to the surface of the coating film.

[0135] There are no particular limitations on the polarized light used for illumination. For example, linearly polarized light, circularly polarized light, and elliptically polarized light can be mentioned, with linearly polarized light being preferred.

[0136] Furthermore, the "tilt direction" of irradiating unpolarized light is not particularly limited as long as it is tilted at a polar angle θ (0 < θ < 90°) relative to the normal direction of the coated film surface. It can be appropriately selected according to the purpose, but θ is preferably 20 to 80°.

[0137] As for the wavelength of polarized or unpolarized light, there is no particular limitation as long as it is light that is photosensitive to photooriented groups. Examples include ultraviolet light, near-ultraviolet light, and visible light, with near-ultraviolet light of 250 to 450 nm being preferred.

[0138] By adjusting the exposure pattern of the coating film formed relative to the coating liquid for coating the alignment film, it is possible to form an alignment film having a region in which the dichroic material disposed on the alignment film is horizontally aligned in one direction and a region in which the dichroic material disposed on the alignment film is vertically aligned.

[0139] Specifically, firstly, a photo-aligned film formed by coating a photo-aligned film with a coating liquid is irradiated with polarized light or with unpolarized light from a direction tilted relative to the surface of the coating film, thereby obtaining a photo-aligned film with orientation constraint force in the horizontal direction.

[0140] Next, through a mask with a predetermined pattern, unpolarized light is irradiated onto the light-aligning film, which has orientation-restricting force in the horizontal direction, from any direction. In the regions of the alignment film irradiated with unpolarized light, the orientation-restricting force disappears. As a result, an alignment film is formed having regions with orientation-restricting force in the horizontal direction and regions without orientation-restricting force. As described later, when a composition for forming anisotropic light-absorbing films, comprising a dichroic substance and a vertical alignment agent, is coated onto such an alignment film, in the regions of the alignment film with orientation-restricting force in the horizontal direction, the dichroic substance is horizontally aligned in one direction; in the regions without orientation-restricting force of the alignment film, the dichroic substance is vertically aligned due to the function of the vertical alignment agent.

[0141] Anisotropic light-absorbing films contain dichroic substances.

[0142] There are no particular limitations on dichroic substances. Examples include visible light absorbing substances (dichroic pigments, dichroic azo compounds), light-emitting substances (fluorescent substances, phosphorescent substances), ultraviolet light absorbing substances, infrared light absorbing substances, nonlinear optical substances, carbon nanotubes, and inorganic substances (such as quantum rods). Previously known dichroic substances (dichroic pigments) can be used.

[0143] The preferred dichroic substance is a dichroic azo dye compound.

[0144] There are no particular limitations on the dichroic azo dye compounds; conventionally known dichroic azo dyes can be used, but compounds described later are preferred.

[0145] In this invention, dichroic azo pigment compounds refer to pigments whose absorbance varies depending on the direction.

[0146] Dichroic azo dye compounds may or may not exhibit liquid crystal properties.

[0147] When a dichroic azo dye compound exhibits liquid crystal properties, it can exhibit either nematic or smectic properties. The preferred temperature range for exhibiting the liquid crystal phase is room temperature (approximately 20°C to 28°C) to 300°C, and more preferably 50°C to 200°C from the viewpoint of processability and manufacturing suitability.

[0148] In this invention, from the viewpoint of hue adjustment, the light absorption anisotropic film preferably includes at least one pigment compound having a maximum absorption wavelength in the range of 560 nm to 700 nm and at least one pigment compound having a maximum absorption wavelength in the range of 455 nm to 560 nm. In the following description, for ease of explanation, the pigment compound having a maximum absorption wavelength in the range of 560 nm to 700 nm will also be referred to as a "first dichroic azo pigment compound." Furthermore, in the following description, for ease of explanation, the pigment compound having a maximum absorption wavelength in the range of 455 nm to 560 nm will also be referred to as a "second dichroic azo pigment compound."

[0149] In this invention, three or more dichroic azo dye compounds may be used together. For example, from the viewpoint of making the light absorption anisotropic film close to black, it is preferable to use a first dichroic azo dye compound, a second dichroic azo dye compound, and at least one dye compound having a maximum absorption wavelength in the range of 380 nm or more and less than 455 nm.

[0150] In this invention, dichroic substances may have polymerizable groups, particularly dichroic azo dye compounds may have polymerizable groups.

[0151] As polymerizable groups, examples include (meth)acryloyl, epoxy, oxetyl, and styryl, with (meth)acryloyl being preferred.

[0152] As described later, an anisotropic light absorption film can be formed using a composition for forming an anisotropic light absorption film containing a dichroic substance having polymerizable groups. In such an anisotropic light absorption film, the polymerizable groups of the dichroic substance react and the dichroic substance is fixed.

[0153] Specifically, examples include paragraphs

[0067] to

[0071] of Japanese Patent Application Publication No. 2013-228706, paragraphs

[0008] to

[0026] of Japanese Patent Application Publication No. 2013-227532, paragraphs

[0008] to

[0015] of Japanese Patent Application Publication No. 2013-209367, paragraphs

[0045] to

[0058] of Japanese Patent Application Publication No. 2013-14883, paragraphs

[0012] to

[0029] of Japanese Patent Application Publication No. 2013-109090, and Japanese Patent Application Publication No. 2013-101328. The following are excerpts from Japanese Patent Application Publication No. 2013-37353, Japanese Patent Application Publication No. 2012-63387, Japanese Patent Application Publication No. 2016-305036, Japanese Patent Application Publication No. 2001-133630, Japanese Patent Application Publication No. 2011-215337, Japanese Patent Application Publication No. 2010-106242, and Japanese Patent Application Publication No. 2010-106242. Paragraphs

[0021] to

[0075] of Japanese Patent Application Publication No. 2010-215846, paragraphs

[0011] to

[0025] of Japanese Patent Application Publication No. 2011-048311, paragraphs

[0017] to

[0069] of Japanese Patent Application Publication No. 2011-213610, paragraphs

[0013] to

[0133] of Japanese Patent Application Publication No. 2011-237513, paragraphs

[0074] to

[0246] of Japanese Patent Application Publication No. 2016-006502, paragraphs

[0005] to

[0051] of International Publication No. 2016 / The dichroic substances described in paragraphs

[0005] to

[0041] of No. 060173, paragraphs

[0008] to

[0062] of International Publication No. 2016 / 136561, paragraphs

[0014] to

[0033] of International Publication No. 2017 / 154835, paragraphs

[0014] to

[0033] of International Publication No. 2017 / 154695, paragraphs

[0013] to

[0037] of International Publication No. 2017 / 195833, and paragraphs

[0014] to

[0034] of International Publication No. 2018 / 164252.

[0154] In addition to dichroic materials, light-absorbing anisotropic films can also contain liquid crystal compounds. By including liquid crystal compounds, dichroic materials can be oriented with a high degree of orientation.

[0155] As a liquid crystal compound, either low-molecular-weight liquid crystal compounds or high-molecular-weight liquid crystal compounds can be used, and a combination of both is preferred. Here, "low-molecular-weight liquid crystal compound" refers to a liquid crystal compound that does not have repeating units in its chemical structure. Here, "high-molecular-weight liquid crystal compound" refers to a liquid crystal compound that has repeating units in its chemical structure.

[0156] From the viewpoint of superior orientation, the liquid crystal compound is preferably a polymeric liquid crystal compound containing repeating units (hereinafter also referred to as "repeating units (1L)") represented by the following formula (1L).

[0157] [Chemical Formula 1]

[0158]

[0159] In the above formula (1L), P1 represents the main chain of the repeating unit, L1 represents a single bond or a divalent linking group, SP1 represents a spacer group, M1 represents a mesocrystalline group, and T1 represents a terminal group.

[0160] As the main chain of the repeating unit represented by P1, specifically, for example, the groups represented by the following formulas (P1-A) to (P1-D) can be cited, of which, from the viewpoint of the diversity of monomers as raw materials and ease of processing, the group represented by the following formula (P1-A) is preferred.

[0161] [Chemical Formula 2]

[0162]

[0163] In equations (P1-A) to (P1-D), "*" indicates the bonding position with L1 in equation (1L). In equations (P1-A) to (P1-D), R... 1 R 2 R 3 and R 4 Each of the above-mentioned alkyl groups independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. The alkyl group can be a straight-chain or branched alkyl group, or an alkyl group having a cyclic structure (cycloalkyl). Furthermore, the number of carbon atoms in the alkyl group is preferably 1 to 5.

[0164] The group represented by formula (P1-A) is preferably a unit of a partial structure of poly(meth)acrylate obtained by polymerization of (meth)acrylate.

[0165] The group represented by formula (P1-B) is preferably an ethylene glycol unit formed by ring-opening polymerization of the epoxy group of a compound having an epoxy group.

[0166] The group represented by formula (P1-C) is preferably a propylene glycol unit formed by ring-opening polymerization of an oxetane compound having an oxetane.

[0167] The group represented by formula (P1-D) is preferably a siloxane unit of a polysiloxane obtained by polycondensation of a compound having at least one of alkoxysilyl and silanol groups. Here, as a compound having at least one of alkoxysilyl and silanol groups, an example is a compound having the formula SiR 4 (OR 5 Compounds containing a group represented by )2-. In the formula, R 4 The meaning of R in equation (P1-D) 4 The meanings are the same, multiple R 5 Alkyl groups, which can be independently represented by 1 to 10 hydrogen or carbon atoms respectively.

[0168] L1 is a single bond or a divalent linker group.

[0169] Examples of divalent linking groups represented by L1 include -C(O)O-, -O-, -S-, and -C(O)NR. 3 -, -SO2- and -NR 3 R 4 - etc. In the formula, R 3 and R 4 Each of the following can be independently represented: a hydrogen atom and an alkyl group having 1 to 6 carbon atoms that may have substituents.

[0170] When P1 is a group represented by formula (P1-A), from the viewpoint of having a better degree of orientation, L1 is preferably a group represented by -C(O)O-.

[0171] When P1 is a group represented by formulas (P1-B) to (P1-D), from the viewpoint of superior orientation, L1 is preferably a single bond.

[0172] From the viewpoint of easy liquid crystal properties or availability of raw materials, the spacer group represented by SP1 preferably includes at least one structure selected from the group consisting of ethylene oxide structure, propylene oxide structure, polysiloxane structure and fluorinated alkylene structure.

[0173] Here, the ethylene oxide structure represented by SP1 is preferably *-(CH2-CH2O). n1 -* represents the group. In the formula, n1 represents an integer from 1 to 20, and * represents the bonding position with L1 or M1 in the above formula (1L). From the viewpoint of better orientation, n1 is preferably an integer from 2 to 10, more preferably an integer from 2 to 4, and even more preferably 3.

[0174] Furthermore, from the viewpoint of superior orientation, the oxypropylene structure represented by SP1 is preferably *-(CH(CH3)-CH2O). n2 -* represents the group. In the formula, n2 represents an integer from 1 to 3, and * represents the bonding position with L1 or M1.

[0175] Furthermore, from the viewpoint of superior orientation, the polysiloxane structure represented by SP1 is preferably *-(Si(CH3)2-O). n3 -* represents the group. In the formula, n3 represents an integer from 6 to 10, and * represents the bonding position with L1 or M1.

[0176] Furthermore, from the viewpoint of superior orientation, the fluorinated alkylene structure represented by SP1 is preferably *-(CF2-CF2). n4 -* represents the group. In the formula, n4 represents an integer from 6 to 10, and * represents the bonding position with L1 or M1.

[0177] The mesocrystalline group represented by M1 is a group that represents the main framework of liquid crystal molecules that contribute to the formation of liquid crystals. Liquid crystal molecules exhibit liquid crystal properties, exhibiting an intermediate state (intermediate phase) between the crystalline state and the isotropic liquid state. There are no particular limitations regarding the mesocrystalline group; for example, one can refer to the description in "Flussige Kristalle in Tabellen II" (VEB Deutsche Verlag fur Grundstoff Industrie, Leipzig, 1984), especially pages 7-16, and the description in "Liquid Crystal Handbook Editorial Committee, Liquid Crystal Handbook" (Maruzen, 2000), especially Chapter 3.

[0178] As a mesocrystalline group, it is preferably at least one group having a cyclic structure selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups and alicyclic groups.

[0179] From the viewpoint of higher orientation, the mesocrystalline group preferably has aromatic hydrocarbon groups, more preferably has 2 to 4 aromatic hydrocarbon groups, and even more preferably has 3 aromatic hydrocarbon groups.

[0180] From the viewpoints of liquid crystal properties, liquid crystal phase transition temperature adjustment, raw material availability and synthetic applicability, and superior orientation, the group represented by the following formula (M1-A) or the following formula (M1-B) is preferred, and the group represented by formula (M1-B) is more preferred.

[0181] [Chemical Formula 3]

[0182]

[0183] In formula (M1-A), A1 is a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups. These groups may be substituted with alkyl, fluorinated alkyl, or alkoxy groups.

[0184] The divalent group represented by A1 is preferably a 4- to 6-membered ring. Furthermore, the divalent group represented by A1 can be a monocyclic ring or a fused ring.

[0185] * indicates the bonding position with SP1 or T1.

[0186] Examples of divalent aromatic hydrocarbon groups represented by A1 include phenylene, naphthylene, fluorene-diyl, anthracene-diyl, and tetraphenyl-diyl. From the viewpoint of the diversity of mesocrystalline framework design or the availability of raw materials, phenylene or naphthylene is preferred, and phenylene is more preferred.

[0187] The divalent heterocyclic group represented by A1 can be either aromatic or non-aromatic, but from the viewpoint of further improving the degree of orientation, a divalent aromatic heterocyclic group is preferred.

[0188] Examples of atoms other than carbon that constitute a divalent aromatic heterocyclic group include nitrogen, sulfur, and oxygen atoms. When an aromatic heterocyclic group has multiple atoms constituting the ring (excluding carbon), these atoms may be the same or different.

[0189] In formula (M1-A), a1 represents an integer from 1 to 10. When a1 is 2 or higher, multiple A1 values ​​can be the same or different.

[0190] In formula (M1-B), A2 and A3 are each independently a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups and alicyclic groups.

[0191] In formula (M1-B), a2 represents an integer from 1 to 10. When a2 is 2 or more, multiple A2s can be the same or different, multiple A3s can be the same or different, and multiple LA1s can be the same or different. From the viewpoint of superior orientation, a2 is preferably an integer of 1 or more, and more preferably 2.

[0192] In formula (M1-B), when a2 is 1, LA1 is a divalent linking group. When a2 is 2 or more, each of the plurality of LA1s is independently a single bond or a divalent linking group, and at least one of the plurality of LA1s is a divalent linking group. When a2 is 2, from the viewpoint of better orientation, it is preferable that one of the two LA1s is a divalent linking group and the other is a single bond.

[0193] In formula (M1-B), examples of divalent linking groups represented by LA1 include -O- and -(CH2). g-、-(CF2) g -、-Si(CH3)2-、-(Si(CH3)2O) g -、-(OSi(CH3)2) g -(g represents an integer from 1 to 10.), -N(Z)-, -C(Z)=C(Z')-, -C(Z)=N-, -N=C(Z)-, -C(Z)2-C(Z')2-, -C(O)-, -OC(O)-, -C(O)O-, -OC(O)O-, -N(Z)C(O)-, - C(O)N(Z)-, -C(Z)=C(Z')-C(O)O-, -OC(O)-C(Z)=C(Z')-, -C(Z)=N-, -N=C(Z)-, -C(Z)=C(Z')-C(O)N(Z”)-, -N(Z”)-C(O)-C(Z)=C(Z’)-, -C(Z)=C(Z')-C(O)-S-, -SC(O)-C(Z)=C(Z')-, -C(Z)=NN=C(Z')- (Z, Z', Z” independently represent hydrogen atoms, alkyl, cycloalkyl, aryl, cyano, or halogen atoms with 1 to 4 carbon atoms, respectively.), -C≡C-, -N=N-, -S-, -S(O)-, -S(O)(O)-, -(O)S(O)O-, -O(O)S(O)O-, -SC(O-), and -C(O)S-, etc. Among these, -C(O)O- is preferred from the viewpoint of superior orientation. LA1 can also be a group composed of two or more of these groups.

[0194] Examples of terminal groups represented by T1 include hydrogen atoms, halogen atoms, cyano groups, nitro groups, hydroxyl groups, alkyl groups with 1 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, alkylthio groups with 1 to 10 carbon atoms, alkoxycarbonyloxy groups with 1 to 10 carbon atoms, alkoxycarbonyl groups with 1 to 10 carbon atoms (ROC(O)-: R is alkyl), acyloxy groups with 1 to 10 carbon atoms, acylamino groups with 1 to 10 carbon atoms, alkoxycarbonylamino groups with 1 to 10 carbon atoms, sulfonylamino groups with 1 to 10 carbon atoms, aminosulfonyl groups with 1 to 10 carbon atoms, carbamoyl groups with 1 to 10 carbon atoms, sulfinyl groups with 1 to 10 carbon atoms, urea groups with 1 to 10 carbon atoms, and groups containing (meth)acryloyloxy groups. As an example of the group containing (meth)acryloyloxy, one can cite the group represented by -LA (L represents a single bond or a linking group. Specific examples of linking groups are the same as L1 and SP1 above. A represents (meth)acryloyloxy).

[0195] From the viewpoint of superior orientation, the content of repeating units (1L) is preferably 20 to 100% by mass relative to the total repeating units of the polymer liquid crystal compound.

[0196] In the case where the polymeric liquid crystal compound contains two repeating units (1L), from the viewpoint of better orientation, it is preferable that in one of the repeating units (A), the terminal group represented by T1 is an alkoxy group, and in the other (B), the terminal group represented by T1 is a group other than an alkoxy group.

[0197] From the viewpoint of superior orientation, in the repeating unit B mentioned above, the terminal group represented by T1 is preferably alkoxycarbonyl, cyano, or a group containing (meth)acryloyloxy, more preferably alkoxycarbonyl or cyano.

[0198] From the viewpoint of superior orientation, the ratio (A / B) of the content of the repeating unit A in the total mass of the polymer liquid crystal compound to the content of the repeating unit B in the total mass of the polymer liquid crystal compound is preferably 50 / 50 to 95 / 5, more preferably 60 / 40 to 93 / 7, and even more preferably 70 / 30 to 90 / 10.

[0199] Furthermore, the polymeric liquid crystal compound can have repeating units (1L) and repeating units that do not contain mesocrystalline groups. As a repeating unit that does not contain mesocrystalline groups, an example is a repeating unit in formula (1L) where M1 is a single bond.

[0200] When a polymeric liquid crystal compound has repeating units that do not contain mesocrystalline groups, from the viewpoint of having better orientation, the percentage of repeating units is preferably more than 0% and less than 30% by mass relative to 100% by mass of the total repeating units in the polymeric liquid crystal compound, and more preferably more than 10% and less than 20% by mass.

[0201] From the viewpoint of achieving better orientation, the weight-average molecular weight (Mw) of the polymeric liquid crystal compound is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. If the Mw of the polymeric liquid crystal compound is within the above range, the processing of the polymeric liquid crystal compound becomes easier.

[0202] In particular, from the viewpoint of suppressing cracks during coating, the weight-average molecular weight (Mw) of the polymer liquid crystal compound is preferably 10,000 or more, and more preferably 10,000 to 300,000.

[0203] Furthermore, from the viewpoint of temperature tolerance of orientation, the weight-average molecular weight (Mw) of the polymer liquid crystal compound is preferably less than 10,000, and preferably more than 2,000 and less than 10,000.

[0204] In this invention, the weight-average molecular weight and number-average molecular weight are values ​​determined by gel permeation chromatography (GPC).

[0205] • Solvent (eluent): N-methylpyrrolidone

[0206] • Device Name: TOSOH HLC-8220GPC

[0207] • String: Connect 3 TOSOH TSKgelSuperAWM-H (6mm×15cm) tubes for use.

[0208] • Column temperature: 25℃

[0209] • Sample concentration: 0.1% by mass

[0210] • Flow rate: 0.35 mL / min

[0211] • Calibration curve: The calibration curve was obtained using seven samples of TSK standard polystyrene prepared by TOSOH CORPORATION with Mw = 2,800,000 to 1,050 (Mw / Mn = 1.03 to 1.06).

[0212] The light-absorbing anisotropic film preferably contains a surfactant.

[0213] By including surfactants, it is expected that the smoothness of the coated surface will be improved and the orientation degree will be further improved, or the in-plane uniformity will be improved by suppressing depressions and unevenness.

[0214] As surfactants, surfactants that make the dichroic pigment compound and the liquid crystal compound horizontal on the coating surface side can be used (horizontal alignment agent), or surfactants that make them vertical can be used (vertical alignment agent). For example, compounds described in paragraphs

[0155] to

[0170] of International Publication No. 2016 / 009648, compounds described in paragraphs

[0253] to

[0293] of Japanese Patent Application Publication No. 2011-237513 (horizontal alignment agent), and compounds described in paragraphs

[0071] to

[0097] of International Publication No. 2019 / 235355 (vertical alignment agent) can be used.

[0215] As a method for manufacturing the above-mentioned light absorption anisotropic film, a method comprising the following steps in sequence is described: a step of coating an alignment film with a composition for forming a light absorption anisotropic film containing a dichroic substance and a liquid crystal compound (hereinafter also referred to as the "coating film forming step"); and a step of aligning the liquid crystal components contained in the coating film (hereinafter also referred to as the "alignment step").

[0216] In addition, liquid crystal components refer to components that not only include the aforementioned liquid crystal compounds, but also, in the case where the aforementioned dichroic substances possess liquid crystal properties, include dichroic substances that also possess liquid crystal properties.

[0217] The composition for forming anisotropic light-absorbing films contains the aforementioned dichroic substance and liquid crystal compound.

[0218] Compositions for forming anisotropic light-absorbing films may include surfactants, polymerization initiators, and solvents.

[0219] In the coating film forming process, the coating method for the composition used to form anisotropic light absorption film can specifically include, for example, known methods such as roller coating, gravure printing, spin coating, wire rod coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0220] The alignment process is the process of orienting the liquid crystal components contained in the coated film. As a result, anisotropic light absorption films can be obtained.

[0221] The orientation process may include a drying process. This drying process removes components such as solvents from the coated film. The drying process can be performed by placing the coated film at room temperature for a specified time (e.g., natural drying), or by heating and / or air supply.

[0222] Here, the liquid crystal components contained in the composition for forming anisotropic light absorption films are sometimes oriented through the above-described coating film forming process or drying process. For example, in the case where the composition for forming anisotropic light absorption films is prepared as a coating liquid containing a solvent, by drying the coating film and removing the solvent from the coating film, a coating film with anisotropic light absorption, i.e., an anisotropic light absorption film, can be obtained.

[0223] From the perspective of manufacturing applicability, the transition temperature of the liquid crystal components contained in the coating film into the liquid crystal phase is preferably 10 to 250°C, more preferably 25 to 190°C.

[0224] The alignment process preferably includes a heat treatment. This allows the liquid crystal components contained in the coated film to be aligned, thus enabling the heat-treated coated film to be preferably used as a light-absorbing anisotropic film.

[0225] From a manufacturing suitability perspective, the heat treatment is preferably performed at 10–250°C, more preferably at 25–190°C. Furthermore, the heating time is preferably 1–300 seconds, more preferably 1–60 seconds.

[0226] Additionally, if necessary, a process for curing the light-absorbing anisotropic film can be performed after the above-mentioned orientation process. This process will be referred to as the "curing process" below.

[0227] For example, when the light-absorbing anisotropic film has crosslinking groups (polymeric groups), the curing process is carried out by heating and / or light irradiation (exposure). Preferably, the curing process is carried out by light irradiation.

[0228] As described above, the diffraction grating polarizer 18 has a structure in which a first region 18a, in which the dichroic material is horizontally oriented in one direction, and a second region 18b, in which the dichroic material is vertically oriented, are alternately arranged in a two-dimensional checkerboard pattern.

[0229] In this invention, the arrangement patterns of the first region 18a and the second region 18b can be any other arrangement patterns, as long as they have a periodic arrangement pattern that functions as a diffraction grating.

[0230] As an example, the arrangement patterns of the first region 18a and the second region 18b, other than the checkerboard pattern, include a striped arrangement pattern, etc.

[0231] Alternatively, it is possible to utilize a structure where only the first region 18a is arranged periodically in a one-dimensional or two-dimensional manner, while all other regions form a so-called island-like structure similar to the second region 18b. As an example, a water droplet pattern formed periodically by multiple circular (roughly circular) first regions 18a and a grid pattern formed periodically by multiple quadrilateral (roughly quadrilateral) first regions 18a can be illustrated.

[0232] Furthermore, there is no limitation on the arrangement interval of the first region 18a and the second region 18b in the diffraction grating polarizer 18, that is, the period of the periodic structure. The interval (period) at which the diffraction grating polarizer 18 can function as a diffraction grating can be appropriately set according to the arrangement pattern, etc.

[0233] The spacing between the first region 18a and the second region 18b is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

[0234] In the lighting device 10 shown in the figure, the diffraction grating polarizer 18 has a first region 18a that aligns the dichroic material horizontally and a second region 18b that aligns the dichroic material vertically. However, in this invention, the (diffraction grating) polarizer is not limited to this.

[0235] That is, in this invention, as long as the polarizer is a polarizer that has two or more regions with different polarization states of transmitted light in the in-plane direction and periodically arranges one or more regions, and functions as a diffraction grating, various structures can be used.

[0236] As described above, the lighting device of the present invention switches the blocking and transmission of incident polarized light in multiple regions arranged on the polarizer by switching the polarized light incident on the polarizer (diffraction grating polarizer). The lighting device of the present invention uses this switching to switch the polarizer between a state where it functions as a diffraction grating and a state where it does not function, or further to switch it between states where it functions as a different diffraction grating.

[0237] Thus, the lighting device of the present invention switches the intensity distribution of the emitted light.

[0238] Therefore, in the lighting device of the present invention, various structures can be used as long as the polarizer (diffraction grating polarizer) has a region that transmits polarized light depending on the polarization state of the light when the light is incident and a region that blocks the polarized light, and one or more regions are arranged periodically.

[0239] As an example, an example is shown in a diffraction grating polarizer 18 having a first region 18a in which the dichroic material is horizontally oriented and a second region 18b in which the dichroic material is vertically oriented, wherein the dichroic material in the second region 18b is dissolved and the region becomes an isotropic region, that is, a polarizer in the same state as optical transmission.

[0240] The dissolution method for the dichroic substance in Region 2, 18b can utilize various known methods, such as thermal exposure using a heat-insulating mask and ultraviolet (UV) exposure using a light-shielding mask to create a difference in solvent solubility between the exposed and unexposed areas. As a method for creating solvent solubility between the exposed and unexposed areas, for example, a method can be illustrated by stereocrosslinking double bond groups (acryloyl and methacrylic acid, etc.) using a photoradical polymerization initiator, thereby reducing solvent solubility.

[0241] Furthermore, as a polarizer, it is also possible to utilize a structure in which the same region as the first region 18a that aligns the dichroic material horizontally is formed on the entire surface, and an opening is made in the region corresponding to the second region 18b.

[0242] As another type of polarizer, an example is shown that utilizes a structure formed by fixing a cholesterol-type liquid crystal layer. Specifically, an example is shown that has regions composed of a cholesterol-type liquid crystal layer and isotropic regions, and the regions composed of the cholesterol-type liquid crystal layer are arranged at least periodically.

[0243] As is well known, cholesterol-type liquid crystal phases selectively reflect circularly polarized light in a specified wavelength range and a specified direction of rotation, while transmitting other light. Therefore, by using a polarization control mechanism to switch the light incident on the polarizer to circularly polarized light and linearly polarized light selectively reflected by the cholesterol-type liquid crystal layer, the intensity distribution of emitted light from point sources and two-dimensional point sources can be switched in the same way as before.

[0244] Furthermore, known methods can be used as polarization control mechanisms to switch light incident on a polarizer into circularly polarized and linearly polarized light. As an example, a liquid crystal cell using a linear polarizer and an IPS (In-Plane-Switching) method is shown. Within the plane of the liquid crystal cell, the direction of the slow axis is switched to a direction with a phase difference of λ / 4 and a direction without λ / 4, thereby switching light incident on the polarizer into circularly polarized and linearly polarized light.

[0245] Furthermore, as a polarizer, a polarizer with a grid pattern can be used to make the polarization state of the transmitted light different in different regions.

[0246] Furthermore, polarizers can block light by reflecting it rather than by absorbing it.

[0247] In the above example, the polarization control mechanism causes light with two different polarization states to be incident on the diffraction grating polarizer 18, thereby the diffraction grating polarizer 18 has two regions, a first region 18a and a second region 18b, with different transmission states of transmitted light. However, the present invention is not limited to this.

[0248] That is, in the lighting device of the present invention, a polarization control mechanism may be used to cause light with three or more different polarization states to be incident on a polarizer, and / or the polarizer may have three or more regions with different transmission states of transmitted light.

[0249] For example, the lighting device of the present invention employs a polarization control mechanism to incident light with three different polarization states onto a polarizer, and the polarizer has a structure with three regions having different transmission states of transmitted light. It can also switch between the following states: a single light source state that emits a beam of light the same as that emitted by the light source 12; a first two-dimensional point light source state that emits point light composed of multiple points arranged in two dimensions; and a second two-dimensional point light source state that emits point light arranged differently from the first two-dimensional point light source.

[0250] The lighting device of the present invention has been described in detail above, but the present invention is not limited to the above examples. Various modifications or changes can be made without departing from the spirit of the present invention.

[0251] Example

[0252] The following examples further illustrate the features of the present invention. The materials, reagents, dosages, quantities, ratios, processing methods, and processing order shown in the following examples can be appropriately modified without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limited by the specific examples shown below.

[0253] [Example]

[0254] <<The Making of Polarizing Sheets>>

[0255] <Construction of the Support>

[0256] A 40 μm thick TAC substrate (manufactured by FUJIFILM Corporation, TG40) was prepared as a support. A polymer coating liquid with the following composition was continuously coated onto this TAC substrate using a #8 winding bar. Then, it was dried with warm air at 100°C for 2 minutes to obtain a support with a 0.8 μm thick polyvinyl alcohol film formed on the TAC substrate.

[0257] In addition, the following polymer coating liquid was prepared by modifying polyvinyl alcohol with a solid content concentration of 4% by mass.

[0258]

[0259] Modified polyvinyl alcohol

[0260] [Chemical Formula 4]

[0261]

[0262] <Formation of Orientation Film>

[0263] To 1 part by mass of photo-alignment material E-1 with the following structure, 41.6 parts by mass of butoxyethanol, 41.6 parts by mass of dipropylene glycol monomethyl ester and 15.8 parts by mass of pure water were added, and the resulting solution was pressure filtered using a 0.45 μm membrane filter to prepare a coating solution for photo-alignment film.

[0264] Next, the obtained photo-aligned film was coated onto the fabricated support using a coating solution and dried at 60°C for 1 minute. Then, the coated film was irradiated with linearly polarized ultraviolet light (illuminance 4.5 mW / cm²) using a polarized ultraviolet exposure device. 2 Cumulative radiation dose 300 mJ / cm 2 (Irradiation with first light) to prepare a photo-aligned film with orientation constraint force in the horizontal direction.

[0265] Next, the obtained photo-aligned film is irradiated with unpolarized ultraviolet light (illuminance 4.5 mW / cm²) from a direction perpendicular to the film surface, through a photomask.2 Cumulative radiation dose 2000 mJ / cm 2 (Second light irradiation) thereby preparing a photo-aligned film thin film with a patterned photo-aligned film.

[0266] In addition, the photomask pattern is set as a checkerboard pattern with a grid size of 20μm on one side.

[0267] [Chemical Formula 5]

[0268]

[0269] <Fabrication of anisotropic light-absorbing films>

[0270] On the obtained patterned photo-aligned film, a light-absorbing anisotropic film forming composition F1 with the following composition is continuously coated by a winding bar, thereby forming a coating layer F.

[0271] Next, the coating layer F is heated at 140°C for 15 seconds and then cooled to room temperature (23°C).

[0272] Next, heat at 75°C for 60 seconds and then cool to room temperature again.

[0273] Then, using an LED light (center wavelength 365nm) at an illuminance of 200mW / cm² 2 By irradiating the film with ultraviolet light for 2 seconds under certain irradiation conditions, an anisotropic light-absorbing film was formed. Thus, a laminate consisting of a TAC substrate (transparent support), a PVA polymer film, a photo-aligned film, and an anisotropic light-absorbing film arranged sequentially adjacent to each other was fabricated.

[0274] In addition, the thickness of the light-absorbing anisotropic film is 2.0 μm.

[0275] Composition of composition F1 for forming anisotropic light-absorbing films

[0276]

[0277]

[0278] Dichroic substance C-1 (maximum absorption wavelength: 570nm)

[0279] [Chemical Formula 6]

[0280]

[0281] Dichroic substance M-1 (maximum absorption wavelength: 466nm)

[0282] [Chemical Formula 7]

[0283]

[0284] Dichroic substance Y-1 (maximum absorption wavelength: 417nm)

[0285] [Chemical Formula 8]

[0286]

[0287] Liquid crystal compound L-1

[0288] [Chemical Formula 9]

[0289]

[0290] Liquid crystal compound L-2 (in the following formulas, the numerical values ​​represent the mass ratio)

[0291] [Chemical Formula 10]

[0292]

[0293] Surfactant S-1

[0294] [Chemical Formula 11]

[0295]

[0296] Surfactant S-2

[0297] [Chemical Formula 12]

[0298]

[0299] The direction of the absorption axis was detected for the fabricated laminate.

[0300] As mentioned above, the absorption axis refers to the direction with the highest transmittance at a wavelength of 550 nm when the transmittance is measured by changing the tilt angle and tilt direction of the thin film relative to the normal direction. For example, it is the average value of the long axis direction of the molecules of the oriented dichroic material.

[0301] In this example, the AxoScan OPMF-1 (manufactured by Opto Science, Inc.) was used to measure the transmittance by changing the tilt angle and tilt direction, and the direction of the absorption axis was detected.

[0302] As a result, it can be confirmed that on the light-absorbing anisotropic film, region A, where the absorption axis is parallel to the surface of the alignment film, and region B, where the absorption axis is perpendicular to the surface of the alignment film, are formed according to the mask pattern (chessboard pattern) of the photomask exposing the light-aligning film.

[0303] That is, it was confirmed that the laminate is a (diffraction grating) polarizer of the present invention, which periodically has regions where the dichroic material is vertically oriented and regions where the dichroic material is horizontally oriented.

[0304] <<Fabrication of the Liquid Crystal Cells Constituting the Polarization Control Mechanism>>

[0305] Two glass substrates were used as insulating substrates, and a common electrode and an alignment film were sequentially formed on the surfaces of the two glass substrates. The common electrode was made of ITO, and a uniformly arranged electrode was formed on the entire main surface of the glass substrate. The alignment film was a horizontal alignment film made of polyimide-based transparent resin.

[0306] A spacer with a specified height of light transmittance is provided on an orientation film.

[0307] Glass substrates with a common electrode and an alignment film are aligned so that their alignment film sides face each other, and the alignment films are held together with a constant gap by spacers. Furthermore, the edges of an insulating substrate are sealed with a sealing material, thus securing the pair of glass substrates.

[0308] After filling the gaps between the alignment films with liquid crystal material, the gaps are hermetically sealed to obtain a liquid crystal cell. A terminal is provided on the common electrode of the fabricated liquid crystal cell, and a specified voltage can be applied by connecting it to a driving circuit.

[0309] Inside the obtained liquid crystal cell, when no voltage is applied, the liquid crystal material in the cell within the gap has a predetermined orientation state due to the orientation limiting force of the alignment film. When a voltage is applied, the liquid crystal molecules are oriented in the thickness direction of the liquid crystal cell due to the action of the electric field.

[0310] The in-plane delay Re(550) without voltage is 279 nm, and the in-plane delay with voltage is 0 nm.

[0311] <<The Making of Lighting Fixtures>>

[0312] A polarization control mechanism is formed by stacking a polyvinyl alcohol linear polarizer (a polarizer made by adsorbing iodine onto polyvinyl alcohol and stretching it) and a liquid crystal cell.

[0313] Furthermore, a green laser pointer (λ = 532 nm) was used as the light source.

[0314] Furthermore, an illumination device was fabricated by sequentially arranging a light source, a polarization control mechanism, and a polarizer (diffraction grating). The polarization control mechanism places a linear polarizer on the light source side. The polarizer places a TAC substrate on the polarization control mechanism side.

[0315] By turning on and off the voltage applied to the liquid crystal cell by the polarization control mechanism, the state of a single light source emitting the same beam of light as the light emitted by the light source can be switched between a two-dimensional point light source emitting point light composed of multiple points arranged in two dimensions.

[0316] Based on the above results, the effectiveness of the present invention can be clearly demonstrated.

[0317] Industrial availability

[0318] Devices capable of switching between ranging and authentication devices are preferred for various applications.

[0319] Symbol Explanation

[0320] 10 - Illumination device, 12 - Light source, 14 - Polarizer, 16 - Liquid crystal cell, 18 - (Diffraction grating) polarizer, 18a - First region, 18b - Second region, 100 - Liquid crystal cell, 110 - First substrate, 111 - Insulating substrate, 113 - First common electrode, 114 - Alignment film, 120 - Second substrate, 121 - Insulating substrate, 122 - Second common electrode, 123 - Alignment film, 130 - Liquid crystal layer.

Claims

1. A lighting device, characterized in that, Includes a light source, a polarization control mechanism, and polarizers. The polarization control mechanism switches the light emitted from the light source into at least two different polarization states and directs it onto the polarizer. The polarizer is a polarizer that has two or more regions with different polarization states of transmitted light in the in-plane direction, and one or more of the regions are periodically arranged, and functions as a diffraction grating. One or more of the regions of the polarizer contain a dichroic material. One or more of the regions containing the dichroic material are regions in which the dichroic material is oriented vertically.

2. The lighting device according to claim 1, wherein, The polarizer has two or more regions with different absorption axes.

3. The lighting device according to claim 1 or 2, wherein, The polarization control mechanism is positioned closer to the light source than the polarizer, and includes a polarizer and a liquid crystal unit sequentially from the light source side.

4. The lighting device according to claim 1, wherein, One or more of the regions containing the dichroic material are regions in which the dichroic material is horizontally oriented.

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