Optical element and lighting device including the same

Abstract

Provided are an optical element capable of arbitrarily processing light incident from a light source, and a lighting device including the optical element. An optical element (120) is provided with a liquid crystal cell (130), a [lambda] / 4 film (150) on the liquid crystal cell, and a reflective plate (160) on the [lambda] / 4 film. The liquid crystal cell includes a plurality of first electrodes (136), a first alignment film (142) on the first electrodes, a liquid crystal layer (140) on the first alignment film, a second alignment film (144) on the liquid crystal layer, and a plurality of second electrodes (138) on the second alignment film. The plurality of first electrodes extend in a first extension direction and are arranged in a stripe shape. The liquid crystal layer includes liquid crystal molecules. The plurality of second electrodes are arranged in a stripe shape and extend in a second extension direction intersecting with the first extension direction at an angle of 80 DEG to 90 DEG.

Description

Technical Field

[0001] One embodiment of the present invention relates to an optical element and a lighting device including the optical element. For example, one embodiment of the present invention relates to a lighting device including a light source and an optical element capable of arbitrarily controlling an illumination area of ​​light from the light source. Background Art

[0002] By applying an electric field to liquid crystals such as nematic liquid crystals to control the orientation of liquid crystal molecules, the refractive index of the liquid crystal can be changed. For example, patent documents 1 and 2 disclose liquid crystal lenses that utilize this characteristic. In these liquid crystal lenses, liquid crystal is arranged between a pair of electrodes, and at least one electrode is composed of a plurality of electrodes arranged in concentric circles. By controlling the AC voltage applied between the pair of electrodes, the shape of the irradiation area of ​​light passing through the liquid crystal lens or light reflected on the liquid crystal lens can be changed.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 62-170933

[0006] Patent Document 2: Japanese Patent Application Publication No. 2010-230887 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] One embodiment of the present invention provides an optical element capable of arbitrarily processing light incident from a light source, and a lighting device including the optical element as one of the technical problems. Alternatively, one embodiment of the present invention provides an optical element capable of arbitrarily processing light from a light source without causing uneven illumination or uneven chromaticity, and a lighting device including the optical element as one of the technical problems. Alternatively, one embodiment of the present invention provides the above optical element and lighting device at low cost as one of the technical problems.

[0009] Technical solutions for solving technical problems

[0010] One embodiment of the present invention is an optical element having a liquid crystal unit, a λ / 4 film on the liquid crystal unit, and a reflector on the λ / 4 film. The liquid crystal unit includes a plurality of first electrodes, a first orientation film on the first electrode, a liquid crystal layer on the first orientation film, a second orientation film on the liquid crystal layer, and a plurality of second electrodes on the second orientation film. The plurality of first electrodes extend in a first extension direction and are arranged in stripes. The liquid crystal layer includes liquid crystal molecules. The plurality of second electrodes are arranged in stripes and extend in a second extension direction that intersects the first extension direction at an angle of 80° or more and 90° or less.

[0011] One embodiment of the present invention is an optical element including a first liquid crystal unit, a second liquid crystal unit on the first liquid crystal unit, and a reflector on the second liquid crystal unit. The first liquid crystal unit and the second liquid crystal unit each include: a plurality of first electrodes arranged in stripes; a first orientation film on the plurality of first electrodes; a liquid crystal layer located on the first orientation film and including liquid crystal molecules; a second orientation film on the liquid crystal layer; and a plurality of second electrodes located on the second orientation film. In each of the first liquid crystal unit and the second liquid crystal unit, the plurality of second electrodes are arranged in stripes and intersect the plurality of first electrodes at an angle of not less than 80° and not more than 90°.

[0012] One of the embodiments of the present invention is a lighting device including a light source configured to irradiate light toward a reflector via the optical element and a liquid crystal cell or a first liquid crystal cell and a second liquid crystal cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic perspective view of a lighting device according to an embodiment of the present invention.

[0014] Figure 2 It is a schematic side view of a lighting device according to an embodiment of the present invention.

[0015] Figure 3 It is a schematic end view of a light source of the lighting device according to the embodiment of the present invention.

[0016] Figure 4 It is a schematic perspective view of a part of the optical element involved in the embodiment of the present invention.

[0017] Figure 5A It is a schematic end view of an optical element according to an embodiment of the present invention.

[0018] Figure 5B It is a schematic end view of an optical element according to an embodiment of the present invention.

[0019] Fig. 6A It is a schematic plan view of a first electrode of an optical element according to an embodiment of the present invention.

[0020] Figure 6B It is a schematic plan view of a first electrode of an optical element according to an embodiment of the present invention.

[0021] Figure 6C It is a schematic plan view of a first electrode of an optical element according to an embodiment of the present invention.

[0022] Fig. 7A This is a schematic end view of a portion of an optical element according to an embodiment of the present invention.

[0023] Figure 7B This is a schematic end view of a portion of an optical element according to an embodiment of the present invention.

[0024] Fig. 8A This is a schematic end view for explaining the operation of the optical element according to the embodiment of the present invention.

[0025] Figure 8B This is a schematic end view for explaining the operation of the optical element according to the embodiment of the present invention.

[0026] Fig. 9 This is a schematic diagram for explaining the operation of the optical element according to the embodiment of the present invention.

[0027] Fig. 10A This is a schematic end view for explaining the operation of the optical element according to the embodiment of the present invention.

[0028] Fig. 10B This is a schematic end view for explaining the operation of the optical element according to the embodiment of the present invention.

[0029] Fig.11 This is a schematic diagram for explaining the operation of the optical element according to the embodiment of the present invention.

[0030] Fig.12 It is a schematic perspective view for explaining the operation of the optical element according to the embodiment of the present invention.

[0031] Fig.13 It is a schematic perspective view of a part of the optical element involved in the embodiment of the present invention.

[0032] Fig.14A It is a timing chart showing a driving method of the lighting device according to the embodiment of the present invention, and a schematic diagram showing an illumination area obtained by the driving method.

[0033] Fig. 14B It is a timing chart showing a driving method of the lighting device according to the embodiment of the present invention, and a schematic diagram showing an illumination area obtained by the driving method.

[0034] Fig. 14C It is a timing chart showing a driving method of the lighting device according to the embodiment of the present invention, and a schematic diagram showing an illumination area obtained by the driving method.

[0035] Fig.15A It is a timing chart showing a driving method of the lighting device according to the embodiment of the present invention, and a schematic diagram showing an illumination area obtained by the driving method.

[0036] Fig. 15B It is a timing chart showing a driving method of the lighting device according to the embodiment of the present invention, and a schematic diagram showing an illumination area obtained by the driving method.

[0037] Fig.16 It is a schematic end view of an optical element according to an embodiment of the present invention.

[0038] Fig.17 It is a schematic end view of an optical element according to an embodiment of the present invention.

[0039] Fig.18 It is a schematic end view of an optical element according to an embodiment of the present invention.

[0040] Fig.19A It is a schematic perspective view of a part of the optical element involved in the embodiment of the present invention.

[0041] Fig.19B It is a schematic plan view of a part of the optical element involved in the embodiment of the present invention.

[0042] Fig. 20A It is a schematic perspective view of a part of the optical element involved in the embodiment of the present invention.

[0043] Fig. 20B It is a schematic plan view of a part of the optical element involved in the embodiment of the present invention.

[0044] Fig.21 It is a schematic perspective view for explaining the operation of the optical element according to the embodiment of the present invention.

[0045] Fig. 22 It is a schematic perspective view of a part of the optical element involved in the embodiment of the present invention.

[0046] Fig.23 It is a timing chart showing a driving method of the lighting device according to the embodiment of the present invention, and a schematic diagram showing an illumination area obtained by the driving method.

[0047] Fig.24 It is a schematic end view of an optical element according to an embodiment of the present invention.

[0048] Fig.25 It is a schematic perspective view for explaining the operation of the optical element according to the embodiment of the present invention. DETAILED DESCRIPTION

[0049] Hereinafter, various embodiments of the present invention will be described with reference to the drawings, etc. However, the present invention can be implemented in various forms without departing from the gist of the present invention, and the present invention is not limited to the description of the embodiments illustrated below.

[0050] The drawings sometimes schematically show the width, thickness, shape, etc. of each part compared with the actual method in order to make the description clearer, but this is only an example and is not used to limit the description of the present invention. In this specification and each figure, the same figure mark is sometimes used to mark the elements with the same function as the description related to the existing figure, and the repeated description is omitted. This symbol is used when multiple identical or similar structures are collectively expressed, and a hyphen and a natural number are added after the symbol when they are expressed separately.

[0051] In the present specification and claims, when expressing the manner of configuring another structure on a certain structure, when it is simply recorded as "on", unless otherwise specified, it includes both the situation where the other structure is configured directly on the certain structure in contact with the certain structure, and the situation where the other structure is further configured above the certain structure via another structure.

[0052] In the present specification and claims, the expression "a certain structure is exposed from another structure" means a mode in which a part of a certain structure is not covered by another structure, and the part not covered by another structure also includes a mode in which it is covered by another structure. In addition, the mode represented by this expression also includes a mode in which a certain structure does not contact with other structures.

[0053] First embodiment

[0054] In this embodiment, a lighting device 100 including an optical element 120 which is one embodiment of the present invention is described.

[0055] 1. Overall structure

[0056] Figure 1 and Figure 2A three-dimensional schematic diagram and a side schematic diagram of the lighting device 100 are respectively shown. As shown in these figures, the lighting device 100 has a light source 110 and an optical element 120 as basic structures, and the optical element 120 has a λ / 4 film 150 and a reflector 160 in addition to a liquid crystal unit 130. The total number of liquid crystal units 130 possessed by the optical element 120 is 1. As an arbitrary structure, the optical element 120 may also have a rotating mechanism 170 or the like for changing the angle of the liquid crystal unit 130 relative to the light source 110. As described later, the light source 110 and the optical element 120 are configured so that light with relatively high directivity (collimated light) is irradiated from the light source 110 to the liquid crystal unit 130 of the optical element 120, and the light from the light source 110 passes through the liquid crystal unit 130 and is reflected by the reflector 160, and the reflected light passes through the liquid crystal unit 130 again (refer to Figure 2 Thus, the light from the light source 110 is diffused and reflected by the optical element 120.

[0057] 2. Light source

[0058] exist Figure 3 , a schematic diagram of the end face of the light source 110 is shown in FIG. The light source 110 includes a main body 112, and a recess 112a is formed in the main body 112. The recess 112a is a bottomed hole, and one or more light-emitting elements 114 are disposed on the recess 112a. The recess 112a has a function of giving directionality to the light emitted from the light-emitting element 114 so that the light is irradiated to the optical element 120. The main body 112 can be constructed in a manner including, for example, metals such as aluminum and stainless steel, polymers such as polyimide, polycarbonate, and acrylic resin, or inorganic oxides such as glass. However, as Figure 3 As shown by the dotted arrow, in order to make the light from the light emitting element 114 reflect and focus in the recess 112a and direct it toward the optical element 120, when using a material that transmits visible light such as glass, polymer, or a material with low reflectivity to visible light to form the main body 112, it is preferable that the surface of the recess 112a is formed of a film with high reflectivity relative to visible light. Examples of such films include films of metals such as aluminum, silver, gold, chromium, and stainless steel, thin films of high-refractive materials such as titanium oxide and tantalum oxide, and laminates of thin films of low-refractive index materials such as silicon oxide and magnesium fluoride. The shape of the recess 112a is appropriately adjusted so that highly directional light can be obtained from the light emitting element 114 in the recess 112a. The optical element 120 is arranged to overlap with the recess 112a to irradiate the light from the light source 110 (see Figure 2 ), and the optical element 120 and the light source 110 are housed together in a housing not shown in the figure.

[0059] The light emitting element 114 is an element having a function of emitting light by supplying current, and its structure is not limited. As a typical example, a light emitting diode (LED) can be cited. The light emitting diode is constituted as an electroluminescent element having an inorganic light emitting body such as gallium nitride or gallium nitride containing indium and a protective film for protecting the electroluminescent element as a basic structure, and emits visible light by electroluminescence.

[0060] The light color of the light emitting element 114 can also be arbitrarily selected. For example, one or more light emitting elements 114 that provide white light to the recess 112a may be provided. Alternatively, a light emitting element 114 that emits red light, a light emitting element 114 that emits green light, and a light emitting element 114 that emits blue light may be provided in the recess 112a to form the light source 110 in such a manner that light of various colors is obtained from the recess 112a.

[0061] The size of the light emitting element 114 is not limited. For example, a light emitting element with an area of ​​1.0×10 4 μm 2 Above and 1.0×10 6 μm 2 Below, 4.0×10 4 μm 2 Above and 5.0×10 5 μm 2 Below, or 9.0×10 4 μm 2 Above and 2.5×10 5 μm 2 As an example, a so-called micro LED having a size of about 320 μm×300 μm can be used as the light emitting element 114 .

[0062] 3. Liquid crystal unit

[0063] exist Figure 4 FIG. 1 shows an expanded stereoscopic schematic diagram of the optical element 120. Figure 5A and Figure 5B The following table shows the Figure 4 Schematic diagram of the end surface of the dotted line A-A' and BB'. Figure 4In the figure, several structures are omitted for easy observation. As can be understood from these figures, the liquid crystal cell 130 includes a substrate 132, a plurality of first electrodes 136 on the substrate 132, a first alignment film 142 on the plurality of first electrodes 136, a liquid crystal layer 140 on the first alignment film 142, a second alignment film 144 on the liquid crystal layer 140, a plurality of second electrodes 138 on the second alignment film 144, and an opposing substrate 134 on the plurality of second electrodes 138. In the following description, the main surfaces of the substrate 132 and the opposing substrate 134 are xy planes, and the direction perpendicular to the xy plane is referred to as the z direction.

[0064] (1) Substrate and Counter Substrate

[0065] The substrate 132 and the opposing substrate 134 are bonded to each other via a sealing member 146 provided in a frame shape. The substrate 132 and the opposing substrate 134 respectively function as base materials for supporting the plurality of first electrodes 136 and the plurality of second electrodes 138, and seal the liquid crystal layer 140. The substrate 132 and the opposing substrate 134 preferably include a material showing a high transmittance to the light from the light emitting element 114 so that the light from the light source 110 can pass therethrough. Therefore, it is preferred that the substrate 132 and the opposing substrate 134 be constructed in a manner including a polymer material such as glass, quartz, or polyimide, polycarbonate, polyester, or acrylic resin. The substrate 132 and the opposing substrate 134 may be constructed to have a strength that does not deform due to a force from the outside, or may be constructed to deform elastically. As Figure 2 As shown, the substrate 132 and the counter substrate 134 may be bonded together in a manner such that a portion of the main surface of the substrate 132 is exposed from the counter substrate 134 .

[0066] (2) First electrode and second electrode

[0067] like Figures 4 to 5B As shown, a plurality of first electrodes 136 are connected to the substrate 132, or are arranged on the substrate 132 via an unillustrated primer layer. The primer layer can be formed by one or more films including silicon-containing inorganic compounds such as silicon nitride and silicon oxide. In order to give the liquid crystal unit 130 a higher light transmittance, the first electrode 136 is preferably formed by a conductive oxide having a higher transmittance to visible light, such as indium tin oxide (ITO) and indium lead oxide (IZO). A plurality of first electrodes 136 extend in the same direction with each other on the xy plane and are configured in a stripe shape. The length of each first electrode 136 (the length of the extension direction of the first electrode 136) also depends on the size of the optical element 120, for example, it can be selected from a range of more than 5 cm and less than 15 cm or more than 1 cm and less than 10 cm. The interval between two adjacent first electrodes 136 can be selected, for example, from a range of more than 1 μm to 30 μm or more than 3 μm to 20 μm.

[0068] Similarly, a plurality of second electrodes 138 are also formed on the counter substrate 134 ( Figure 5A , Figure 5B In order to impart high light transmittance to the liquid crystal unit 130, the second electrode 138 is preferably also formed of a conductive oxide such as ITO or IZO having a high transmittance to visible light. The plurality of second electrodes 138 also extend in the same direction relative to each other on the xy plane and are arranged in a stripe shape. The length of each second electrode 138 (the length in the extension direction of the second electrode 138) can also be selected from a range of greater than 5 cm and less than 15 cm or greater than 1 cm and less than 10 cm. In addition, the interval between two adjacent second electrodes 138 can also be selected, for example, from a range of greater than 1 μm to 30 μm or greater than 3 μm to 20 μm.

[0069] Here, the plurality of first electrodes 136 and second electrodes 138 are arranged to cross each other in the z direction (i.e., the direction observed from the opposing substrate 134 side of the liquid crystal unit 130, also referred to as "when viewed from above") in which they overlap. The extension direction of the first electrode 136 and the extension direction of the second electrode 138 may be perpendicular to each other in the z direction, but it is preferred that these directions are not completely perpendicular. For example, the angle formed by the extension direction of the first electrode 136 and the extension direction of the second electrode 138 in the z direction may be set within a range of 80° or more and less than 90°.

[0070] like Figure 4 As shown, every other first electrode 136 selected from a plurality of first electrodes 136 is connected to the first wiring 154-1, and the remaining first electrodes 136 are connected to other wirings (second wirings) 154-2 that are electrically independent from the first wiring 154-1. The first wiring 154-1 and the second wiring 154-2 form terminals 156 at their respective ends, and the terminals 156 are exposed from the opposing substrate 134. Similarly, although not shown in the figure, every other second electrode 138 selected from a plurality of second electrodes 138 is also connected to a wiring (third wiring) not shown in the figure, and the remaining second electrodes 138 are also connected to other wirings (fourth wiring). The third wiring and the fourth wiring also form terminals not shown in the figure. Voltage is supplied to the first electrode 136 and the second electrode 138 from an external circuit not shown in the figure through these terminals. With such a structure, every other selected first electrode 136, other first electrodes 136, every other selected second electrode 138, and other second electrodes 138 can be independently driven.

[0071] A pulsed AC voltage (AC rectangular wave) is applied to the plurality of first electrodes 136. However, the AC voltage is applied in a manner that the phase is reversed between two adjacent first electrodes 136. Similarly, a pulsed AC voltage is applied to the plurality of second electrodes 138 in a manner that the phase is reversed between two adjacent second electrodes 138. Therefore, an AC voltage may be applied only to the first electrode 136, and no voltage may be applied to the second electrode 138 or a constant voltage may be supplied, or vice versa.

[0072] (3) Liquid crystal layer, first alignment film, and second alignment film

[0073] The liquid crystal layer 140 includes liquid crystal molecules. The structure of the liquid crystal molecules is not limited. In this embodiment, positive nematic liquid crystal is used, but smectic liquid crystal, cholesteric liquid crystal, and chiral smectic liquid crystal may also be used. The liquid crystal layer 140 is sealed in a space formed by the substrate 132, the counter substrate 134, and the seal 146 in a manner sandwiched by the first alignment film 142 and the second alignment film 144.

[0074] The thickness of the liquid crystal layer 140, that is, the distance between the first orientation film 142 and the second orientation film 144, is also arbitrary, but is preferably larger than the spacing between the first electrode 136 and the second electrode 138. For example, the thickness of the liquid crystal layer 140 is preferably set to be greater than 1.2 times and less than 10 times, greater than 1.5 times and less than 5 times, or greater than 1.6 times and less than 3 times the spacing between the first electrode 136 or the second electrode 138. Specifically, the thickness of the liquid crystal layer 140 can be selected from a range of, for example, greater than 10 μm and less than 60 μm or greater than 10 μm and less than 50 μm. Although not shown in the figure, a spacer for maintaining the thickness in the entire liquid crystal unit 130 can also be provided in the liquid crystal layer 140. It should be noted that when the above-mentioned thickness of the liquid crystal layer 140 is adopted in a liquid crystal display device, the high responsiveness required for displaying dynamic images cannot be obtained, and it is difficult to perform the function as a liquid crystal display device.

[0075] The first orientation film 142 and the second orientation film 144 include polymers such as polyimide and polyester, and sandwich the liquid crystal layer 140. The first orientation film 142 is configured to align the liquid crystal molecules contained in the liquid crystal layer 140 in a certain direction when there is no electric field (lateral electric field) between the adjacent first electrodes 136 (that is, when no voltage is applied to the plurality of first electrodes 136 or when there is no potential difference between the adjacent first electrodes 136). Similarly, the second orientation film 144 is also configured to align the liquid crystal molecules contained in the liquid crystal layer 140 in a certain direction when there is no lateral electric field between the plurality of second electrodes 138 (that is, when no voltage is applied to the plurality of second electrodes 138 or when there is no potential difference between the adjacent second electrodes 138). Hereinafter, the direction in which the first orientation film 142 and the second orientation film 144 align the liquid crystal molecules in the absence of an electric field is referred to as an alignment direction. The alignment direction can be given, for example, by rubbing treatment. Alternatively, the alignment direction can be given to the first orientation film 142 and the second orientation film 144 by photo-alignment. Photo-alignment is an alignment process using light rubbing, for example, irradiating an alignment film that has not been rubbed with polarized light in the ultraviolet region from a predetermined direction, thereby causing a photoreaction in the alignment film, introducing anisotropy to the surface of the alignment film and imparting a liquid crystal alignment control function.

[0076] like Figure 5A and Figure 5B As shown, the liquid crystal unit 130 is configured such that the orientation directions of the first orientation film 142 and the second orientation film 144 are orthogonal to each other in the z direction, or the angle formed by each other in the z direction is greater than 80° and less than 90°. Fig. 6A As shown, the plurality of first electrodes 136 and the first alignment film 142 may be arranged in a manner such that the extension direction of the plurality of first electrodes 136 and the alignment direction of the first alignment film 142 (see white arrows) are perpendicular to each other in the z direction, or may be arranged as shown in FIG. Figure 6B As shown, the plurality of first electrodes 136 are arranged in a manner that the extension direction of the plurality of first electrodes 136 and the orientation direction of the first orientation film 142 are not completely perpendicular in the z direction. In the latter case, the angle formed by the extension direction of the plurality of first electrodes 136 and the orientation direction of the first orientation film 142 in the z direction can be selected from the range of 80° or more and less than 90° or 85° or more and less than 90°. Although not shown in the figure, the relationship between the plurality of second electrodes 138 and the second orientation film 144 is the same. That is, the plurality of second electrodes 138 and the second orientation film 144 can be arranged so that the extension direction of the plurality of second electrodes 138 is perpendicular to the orientation direction of the second orientation film 144 in the z direction, or can be arranged so that the angle formed by the extension direction of the plurality of second electrodes 138 and the orientation direction of the second orientation film 144 in the z direction is 80° or more and less than 90° or 85° or more and less than 90°.

[0077] Here, the extending direction of each first electrode 136 refers to: Fig. 6A When the line shape is shown in FIG. 1 , the direction from the intersection with the first wiring 154-1 or the second wiring 154-2 to the front end of the first electrode 136 is the same as that shown in FIG. Figure 6C As shown, each first electrode 136 can have a curved structure including a plurality of straight line portions. For example, each first electrode 136 can be configured to have a pair of straight line portions 136b sandwiching a bending point 136a. In this case, the plurality of first electrodes 136 are configured in such a manner that the angle formed by the extension direction of at least one straight line portion 136b and the orientation direction of the first orientation film 142 in the z direction is 80° or more and 90° or 85° or more and 90° or less. The same is true for the second electrode 138. That is, the extension direction of each second electrode 138 is the direction from the intersection with the third wiring or the fourth wiring to the front end of the second electrode 138 when the second electrode 138 as a whole has a straight line shape. Each second electrode 138 can also have a curved structure including a plurality of straight line portions. In this case, the plurality of second electrodes 138 are configured in such a manner that the angle formed by the extension direction of at least one straight line portion and the orientation direction of the second orientation film 144 in the z direction is 80° or more and 90° or more and 85° or less.

[0078] 4.λ / 4 film

[0079] The λ / 4 film 150 is one of the phase difference films, and is a film that gives a phase difference of λ / 4 (π / 2) between two perpendicular polarized components of incident light and emits the light. The λ / 4 film 150 can be made of a polymer having high visible light transmittance such as polycarbonate or cycloolefin polymer, polymethacrylate, etc., which has been subjected to stretching and orientation treatment, or a liquid crystal polymer subjected to orientation treatment. The λ / 4 film 150 can be directly provided on the counter substrate 134, or it can be provided on the counter substrate 134 (opposite to the liquid crystal layer 140) via an adhesive layer not shown (see FIG. 1 ). Figures 4 to 5B ).

[0080] 5. Reflector

[0081] like Figures 4 to 5B As shown, the reflector 160 is provided on the λ / 4 film 150 and is configured to not transmit visible light but to reflect visible light. Therefore, the reflector 160 is made of a metal having a high reflectivity in a wide wavelength range of the visible light region, such as silver or aluminum, and is formed to have a thickness (e.g., 20 nm or more or 50 nm or more) that does not transmit visible light. Figures 4 to 5B As shown in FIG. 1 , the reflector 160 may be formed by bonding the above-mentioned metal film (foil) or metal plate to the λ / 4 film 150. Alternatively, as shown in FIG. Fig. 7AAs shown in FIG. 1 , a laminated body including a support substrate 164 made of a polymer such as glass, quartz, polycarbonate, polyester, or polyimide, and a reflective film 162 formed on the support substrate 164 may be bonded to the λ / 4 film 150 as the reflector 160. Alternatively, as Figure 7B As shown, a λ / 4 film 150 and a reflector 160 may be disposed between the counter substrate 134 and the second electrode 138 .

[0082] 6. Other structures

[0083] As an optional structure, the optical element 120 may include a rotation mechanism 170 ( Figure 2 The structure of the rotating mechanism 170 is arbitrary as long as it can rotate the optical element 120 around a rotation axis perpendicular to the direction of light emitted from the light source 110 (or the direction in which the recess 112a extends) (see Figure 2 In addition, the rotating mechanism 170 may be configured to rotate the optical element 120 around a rotation axis parallel to the direction of the light emitted from the light source 110 (see Figure 2 By providing the rotating mechanism 170, the light from the light source 110 can be emitted in any direction.

[0084] like Figures 4 to 5B As shown, the optical element 120 may further include an anti-reflection film 166 as a structure for suppressing the light from the light source 110 from being reflected on the substrate 132 and allowing the light to efficiently reach the reflector 160. The anti-reflection film 166 is provided on the bottom surface of the substrate 132 (the surface on the opposite side of the opposing substrate 134). As the anti-reflection film 166, a known anti-reflection film (AR film) may be used. For example, a laminate of a base film and an anti-reflection film having different refractive indices may be used as the anti-reflection film 166. As an example, a laminate formed by depositing a thin film of a fluorine-containing resin or silicon dioxide or titanium dioxide on a polymer filler exemplified by polyester such as polyethylene terephthalate or cellulose such as triacetyl cellulose may be used as the anti-reflection film 166. By providing the anti-reflection film 166, it is possible to prevent the light reflected on the substrate 132 from reaching the irradiation area, so that the shape and size of the irradiation area can be controlled more precisely.

[0085] 7. Configuration of optical components relative to the light source

[0086] As described later, in the lighting device 100, the light from the light source 110 passes through the liquid crystal cell 130 of the optical element 120 twice and is diffused, thereby making it possible to process the light from the light source 110 into light that provides an irradiation area of ​​various shapes. Therefore, the optical element 120 is configured so that the liquid crystal cell 130 overlaps with the concave portion 112a of the light source 110, and the light from the light source 110 passes through the liquid crystal cell 130 and the λ / 4 film 150 and is reflected by the reflector 160, and the reflected light passes through the λ / 4 film 150 and the liquid crystal cell 130 again (see Figure 2 , Figure 5A and Figure 5B More specifically, the light source 110 and the optical element 120 are arranged so that the light of the light source 110 is irradiated with the liquid crystal unit 130 at an incident angle of 15° or more and 75° or less. That is, the light of the light source 110 is irradiated with the liquid crystal unit 130 in a direction parallel to the normal line NL of the surfaces of the substrate 132, the counter substrate 134, and the reflector 160 (see Figure 5A The light source 110 and the optical element 120 are arranged so that the angle θ formed by the direction of light propagation of the light source 110 (or the extension direction of the recess 112a) is greater than 15° and less than 75°. The rotating mechanism 170 only needs to be configured so as to rotate the liquid crystal unit 130 within this angle.

[0087] 8. Light distribution control of optical components

[0088] The optical element 120 diffuses the light irradiated from the light source 110 in a certain direction. Therefore, by appropriately driving the optical element 120, the light from the light source 110 can be processed into an arbitrary shape, and as a result, the shape of the area where the lighting device 100 irradiates the object, that is, the irradiation area, can be arbitrarily controlled. Hereinafter, the diffusion of light in the liquid crystal unit 130 will be described using a method in which the first electrode 136 and the second electrode 138 extend in the x direction and the y direction, respectively. It should be noted that in the following description, in order to facilitate understanding, the light from the light source 110 is used to be irradiated perpendicularly to the liquid crystal unit 130, that is, in the z direction, but it is hoped that attention will be paid to the fact that the light also behaves in the same manner when the light is incident on the optical element 120 in a direction deviating from the z direction.

[0089] (1) When not driving

[0090] Fig. 8A and Figure 8B An end view schematically showing a state of the liquid crystal cell 130 when not driven is shown. Fig. 8A and Figure 8B The end view diagrams are respectively viewed from the x direction and the y direction. In the following figures, the liquid crystal molecules are schematically represented by white ovals or circles.

[0091] The case where the liquid crystal unit 130 is not driven refers to the case where no voltage is applied or a certain voltage is applied to the plurality of first electrodes 136 and the plurality of second electrodes 138. In this case, since no lateral electric field is generated between the plurality of first electrodes 136 and between the plurality of second electrodes 138, the liquid crystal molecules are oriented along the orientation direction of the first orientation film 142 and the second orientation film 144. The liquid crystal molecules are oriented along the orientation direction of the first orientation film 142 near the substrate 132 (here, the direction at an angle of 80° or more and 90° or less relative to the y direction or the x direction), and rotate around the z direction as the center axis and twist by 90° as they approach the opposing substrate 134.

[0092] Therefore, the light emitted from the light source 110 does not diffuse but stays on the optical rotation when it travels from the liquid crystal unit 130 to the reflector 160. Fig. 9 As shown, light having a polarization component in the x direction starting from the light source 110 (polarization component x) becomes light having a polarization component in the y direction (polarization component y) with 90° rotation when passing through the liquid crystal layer 140. Similarly, the polarization component y perpendicular to the polarization component x also produces 90° polarization and becomes the polarization component x.

[0093] Then, the light passes through the λ / 4 film 150, is reflected by the reflector 160, and passes through the λ / 4 film 150 again. Therefore, the light that passes through the liquid crystal layer 140 and is optically rotated to become the polarization component y is secondarily phase-shifted by λ / 4 by the λ / 4 film 150, and thus becomes the polarization component x with a phase shift of λ / 2 (i.e., 90°), and enters the liquid crystal layer 140 again and is optically rotated. As a result, the light that originally entered the optical element 120 as the polarization component x is emitted from the optical element 120 as reflected light of the polarization component y. Similarly, the light that passes through the liquid crystal layer 140 and is optically rotated to become the polarization component x is secondarily phase-shifted by λ / 4 by the λ / 4 film 150, and enters the liquid crystal layer 140 again and is optically rotated. As a result, the light that originally entered the optical element 120 as the polarization component y is emitted from the optical element 120 as reflected light of the polarization component x. However, since there is no electric field in the liquid crystal layer 140, the orientation of the liquid crystal molecules does not change. Therefore, the liquid crystal layer 140 does not have a refractive index distribution and does not diffuse light. Therefore, when the liquid crystal cell 130 is not driven, the collimated light from the light source 110 is emitted from the optical element 120 without being diffused, so that light having a small irradiation area can be provided.

[0094] (2) When driving

[0095] Fig. 10A and Fig. 10B FIG. 1 is a schematic end view of the liquid crystal unit 130 when being driven. Fig. 10A and Fig. 10B Corresponding to Fig. 8A and Figure 8BOne way to drive the liquid crystal unit 130 is to apply a pulsed AC voltage to the plurality of first electrodes 136 and the plurality of second electrodes 138 so as to reverse the phase between the adjacent first electrodes 136 and the second electrodes 138. The frequencies of the AC voltages applied to the first electrodes 136 and the second electrodes 138 are the same. The AC voltage can be selected, for example, from a range of 3V to 50V or from 3V to 30V. Since the directions in which the first electrodes 136 and the second electrodes 138 extend are orthogonal or intersect at an angle of 80° to less than 90°, a lateral electric field is generated between adjacent first electrodes 136 and between adjacent second electrodes 138 by applying an AC voltage, which is orthogonal or intersects at an angle of 80° to less than 90° (see Fig. 10A and Fig. 10B An electric field (vertical electric field) is also generated between the first electrode 136 and the second electrode 138, but the thickness of the liquid crystal layer 140 is larger than the interval between the adjacent first electrodes 136 and the second electrode 138. Therefore, the longitudinal electric field is very small relative to the transverse electric field and can be ignored, so each liquid crystal molecule is aligned according to the transverse electric field.

[0096] When a lateral electric field is generated in the liquid crystal layer 140, the liquid crystal molecules on the first electrode 136 side are oriented in the direction of the lateral electric field, while being oriented in an upward convex arc shape between adjacent first electrodes 136 ( Fig. 10A ). Similarly, on the second electrode 138 side, the liquid crystal molecules are oriented in the direction of the lateral electric field, and are oriented in a downwardly convex arc shape between adjacent second electrodes 138 ( Fig. 10B ). Such a change in the orientation of the liquid crystal molecules generates a refractive index distribution in the liquid crystal layer 140. As a result, Fig.11 As shown, the component parallel to the transverse electric field formed by the first electrode 136, i.e., the polarized component y, of the light incident on the liquid crystal layer 140 from the substrate 132 of the liquid crystal cell 130 is refracted by the refractive index distribution formed on the substrate 132 of the liquid crystal layer 140 and diffused in the y direction. When the light is optically rotated in the liquid crystal layer 140, it becomes the polarized component x, i.e., the component parallel to the transverse electric field formed by the second electrode 138, and therefore diffuses in the x direction by the refractive index distribution formed on the opposite substrate 134 side of the liquid crystal layer 140. Thus, the polarized component y diffuses in the x direction and the y direction when passing through the liquid crystal layer 140 once.

[0097] Furthermore, the light passes through the λ / 4 film 150, is reflected by the reflector 160, and passes through the λ / 4 film 150 again, becoming a polarized component y, and enters the liquid crystal layer 140 again. The polarization direction of the polarized component y is orthogonal to the orientation direction of the liquid crystal molecules formed by the second electrode 138 of the liquid crystal layer 140, or crosses at an angle of 80° or more and less than 90°, so it is almost unaffected by the refractive index distribution and does not diffuse substantially. In addition, when the light changes into the polarized component x through the liquid crystal layer 140, the polarization direction of the polarized component x is orthogonal to the orientation direction of the liquid crystal molecules formed on the first electrode 136 side of the liquid crystal layer 140, or crosses at an angle of 80° or more and less than 90°, so it does not diffuse substantially. Through the above mechanism, one polarized component y becomes a polarized component y that diffuses once in the x direction and the y direction respectively, and is emitted from the optical element 120. The same mechanism also acts on the polarization component x irradiated to the optical element 120 , and as a result, the polarization component x becomes the polarization component x diffused once in the x direction and once in the y direction, and is emitted from the optical element 120 .

[0098] As described above, the first electrode 136 and the second electrode 138 can be driven independently. Therefore, a refractive index distribution can be formed only on the first electrode 136 or the second electrode 138 side of the liquid crystal layer 140, and the diffusion direction and the number of diffusions can be appropriately controlled.

[0099] (3) Light processing

[0100] By using this mechanism, Fig.12 As shown in FIG. 1 , assuming that the optical element 120 does not exist, the light source 110 can form an irradiation area 174 that is greatly expanded compared to the virtual irradiation area 172 formed on the irradiation object. In addition, by appropriately controlling the voltage supplied to the first electrode 136 and the second electrode 138, the irradiation area can be arbitrarily controlled. For example, Fig.13 As shown, voltages V1 and V2 are alternately provided to the plurality of first electrodes 136 through the first wiring 154-1 and the second wiring 154-2, and voltages V3 and V4 are alternately provided to the plurality of second electrodes 138 through the third wiring 154-3 and the fourth wiring 154-4. When the voltages V1, V2, V3, and V4 are set to 0 or fixed, the liquid crystal unit 130 becomes non-driven, and thus light is provided to the relatively narrow irradiation area 174-1 ( Fig.14A ). In contrast, by synchronizing the voltages V1 and V3, setting the voltages V2 and V4 to have opposite phases to the voltages V1 and V3, and making the voltages V1, V2, V3, and V4 the same, the light from the light source 110 can be processed to provide light that irradiates the area 174-2 equally in the x-direction and the y-direction ( Fig. 14B). Therefore, although the irradiation area 174-2 is substantially the same shape as the virtual irradiation area 172, it is larger than the virtual irradiation area 172. Alternatively, by synchronizing the voltages V1 and V3, setting the voltages V2 and V4 to have opposite phases to the voltages V1 or V3, and making the voltages V1 and V2 smaller than the voltages V3 and V4, the light from the light source 110 can be processed to provide the light of the irradiation area 174-3 that spreads more in the x direction than in the y direction ( Fig. 14C ). If the virtual irradiation area 172 is circular, the irradiation area 174-3 becomes an ellipse. Alternatively, by reversing the voltages V1 and V2 and setting the voltages V3 and V4 to 0 or fixed, the light from the light source 110 can be processed to provide the light of the irradiation area 174-4 that is diffused in the y direction and grows ( Fig.15A ). On the contrary, by reversing the voltages V3 and V4 and making the voltages V1 and V2 0 or fixed, the light from the light source 110 can be processed into light that provides a horizontally long irradiation area 174-5 that diffuses in the x direction ( Fig. 15B ).

[0101] As described above, in the lighting device 100 involved in this embodiment, by using the optical element 120 including the single liquid crystal unit 130, the two polarized components of the light from the light source 110 can be diffused one by one, so that various shapes of irradiation areas can be provided. In the existing lighting device, if it is considered that a plurality of liquid crystal units are required to diffuse the two polarized components of the light from the light source, by implementing this embodiment, not only the miniaturization of the optical element can be achieved, but also a lighting device with a variable irradiation area can be provided at a low cost.

[0102] Second embodiment

[0103] In this embodiment, an optical element 122 having a different structure from the optical element 120 described in the first embodiment is described. The description of the same or similar structure as that described in the first embodiment may be omitted.

[0104] 1. Structure

[0105] One of the differences between the optical element 122 and the optical element 120 is that Fig.16As shown, the optical element 122 includes two liquid crystal cells (a first liquid crystal cell 130-1 and a second liquid crystal cell 130-2) that overlap each other in the z direction. In other words, the total number of liquid crystal cells 130 included in the optical element 122 is two. The structures of the first liquid crystal cell 130-1 and the second liquid crystal cell 130-2 are the same as the structure of the liquid crystal cell 130 of the optical element 120. By using the first liquid crystal cell 130-1 and the second liquid crystal cell 130-2 having the same structure, the productivity of the optical element 122 can be improved, and the optical element 122 and the lighting device 100 including the same can be provided at a lower cost. The first liquid crystal cell 130-1 and the second liquid crystal cell 130-2 are fixed to each other by a light-transmitting bonding layer 152. The light from the light source 110 passes through the first liquid crystal cell 130-1 and the second liquid crystal cell 130-2 in sequence, is reflected on the reflective plate 160, passes through the second liquid crystal cell 130-2 and the first liquid crystal cell 130-1 in sequence again, and is emitted from the optical element 122. Although not shown, the optical element 122 may include an anti-reflection film 166 on the bottom surface side of the substrate 132 of the first liquid crystal cell 130 - 1 .

[0106] As described later, in the optical element 122, the extension direction of the first electrode 136-1 of the first liquid crystal unit 130-1 can be parallel to the extension direction of the first electrode 136-2 of the second liquid crystal unit 130-2 or form an angle of 0° to 10°. Therefore, the extension direction of the second electrode 138-1 of the first liquid crystal unit 130-1 is also parallel to the extension direction of the second electrode 138-2 of the second liquid crystal unit 130-2 or form an angle of 0° to 10°. In addition, as Fig.16 As shown, the optical element 122 does not need the λ / 4 film 150, and the reflector 160 can be provided directly on the counter substrate 134 or via a bonding layer not shown. Fig.17 As shown, the reflector 160 as a reflective layer can be disposed between the second electrode 138-2 of the second liquid crystal unit 130-2 and the opposing substrate 134-2. In this case, an insulating layer 168 is disposed between the reflector 160 and the second electrode 138-2 to electrically insulate the reflector 160 and the second electrode 138-2 from each other. The insulating layer 168 can be formed, for example, using a polymer such as acrylic resin, epoxy resin, or one or more films containing silicon-containing inorganic compounds such as silicon oxide and silicon nitride. Alternatively, as Fig.18 As shown, the counter substrate 134-2 may be replaced with a reflector 160. In this case, an insulating layer 168 may be provided to electrically insulate the reflector 160 and the second electrode 138-2 from each other.

[0107] exist Fig.19A and Fig.19B1 and 2 respectively show a perspective view and a top view of a configuration of a first electrode 136-1 and a second electrode 138-1 selected from the first liquid crystal unit 130-1, and a first electrode 136-2 and a second electrode 138-2 selected from the second liquid crystal unit 130-2. Fig.19A As shown, the first electrode 136-1 and the first electrode 136-2 may be parallel to each other, and / or the second electrode 138-1 and the second electrode 138-2 may also be parallel to each other. Fig.19B As shown, the directions in which the first electrode 136-1 and the first electrode 136-2 extend deviate in the z direction, and similarly, the directions in which the second electrode 138-1 and the second electrode 138-2 extend also deviate in the z direction. Fig.19B In the case of the configuration relationship shown, if the first electrode 136-1, the second electrode 138-1, the first electrode 136-2 and the second electrode 138-2 are virtually moved in parallel in the xy plane in a manner that overlaps in the z direction, the first liquid crystal unit 130-1 and the second liquid crystal unit 130-2 can be formed in a manner that the extension directions of these electrodes are different from each other in the z direction.

[0108] The same is true for the case where the first electrode 136-1, the second electrode 138-1, the first electrode 136-2 or the second electrode 138-2 has a bent structure. Fig. 20A As shown, the first electrode 136-1 and the first electrode 136-2 may completely overlap in the z direction, and / or the second electrode 138-1 and the second electrode 138-2 may completely overlap in the z direction. Fig. 20B As shown, the first liquid crystal unit 130-1 and the second liquid crystal unit 130-2 may be configured and arranged in such a manner that two adjacent straight line portions of the first electrode 136-1, two adjacent straight line portions of the second electrode 138-1, two adjacent straight line portions of the first electrode 136-2, and two adjacent straight line portions of the second electrode 138-2 extend in different directions. In this case, the straight line portions of the first electrode 136-1, the second electrode 138-1, the first electrode 136-2, and the second electrode 138-2 extend in different directions on the xy plane. In other words, when the first electrode 136-1, the second electrode 138-1, the first electrode 136-2, and the second electrode 138-2 are virtually moved in parallel in such a manner that the bending points overlap in the z direction, the respective straight line portions extend in different directions on the xy plane.

[0109] Thus, by configuring the optical element 122 so that the first electrodes 136 do not completely overlap in the z direction and the second electrodes 138 do not completely overlap between the two liquid crystal cells 130, interference of light caused by these electrodes is suppressed, and as a result, it is possible to prevent uneven illumination or uneven color from occurring in the light emitted from the optical element 122. Therefore, the color of the light from the light source 110 can be faithfully reproduced in the irradiated area.

[0110] 2. Light distribution control of optical components

[0111] By using the optical element 122 having two liquid crystal cells 130, light can be diffused more effectively. Fig.21 As shown, if all the first electrodes 136 and the second electrodes 138 of the first liquid crystal cell 130-1 and the second liquid crystal cell 130-2 are driven, a refractive index distribution is generated in the liquid crystal layer 140-1 of the first liquid crystal cell 130-1 and the liquid crystal layer 140-2 of the second liquid crystal cell 130-2, as in the first embodiment. Therefore, one polarization component (here, polarization component x) of the light from the light source 110 does not diffuse in the liquid crystal layer 140-1 and remains at 90° optical rotation, but diffuses in the x-direction and y-direction while being optically rotated 90° on the liquid crystal layer 140-2. After the light is further reflected by the reflector 160, it is diffused in the x-direction and y-direction while being optically rotated 90° again on the liquid crystal layer 140-2, and is not diffused in the liquid crystal layer 140-1 but is optically rotated 90°. As a result, the optical element 122 converts the incident polarization component x into the polarization component x diffused twice in the x-direction and the y-direction. The other polarization component (here, polarization component y) of the light from light source 110 also becomes polarization component y diffused twice in the x direction and twice in the y direction.

[0112] Thus, since the light from the light source 110 can be diffused multiple times in the x-direction and the y-direction (for example, three times or more), coloration of the light caused by insufficient diffusion can be suppressed. In addition, an irradiation area having various shapes such as a circle, an ellipse, and a line can be obtained. For example, Fig. 22 As shown, the voltages V1 and V2 are alternately provided to the plurality of first electrodes 136-1 of the first liquid crystal unit 130-1, the voltages V3 and V4 are alternately provided to the plurality of second electrodes 138-1 of the first liquid crystal unit 130-1, the voltages V5 and V6 are alternately provided to the plurality of first electrodes 136-2 of the second liquid crystal unit 130-2, and the voltages V7 and V8 are alternately provided to the plurality of second electrodes 138-2 of the second liquid crystal unit 130-2. Fig.23As shown, by synchronizing voltages V1 and V7, setting voltages V2 and V8 to opposite phases to voltage V1 or V7, and setting voltages V3, V4, V5, and V6 to 0 or fixed, the light provided in a circular irradiation area 174-1 from the light source 110 can be processed into light provided in a cross-shaped irradiation area 174-6. The length of the cross-shaped branches can be controlled by appropriately changing the magnitudes of voltages V1, V2, V7, and V8.

[0113] 3. Modifications

[0114] The structure of the optical element involved in the embodiment of the present invention is not limited to the above-mentioned structure. Fig.24 As in the optical element 124 according to the present modification shown in the figure, the first liquid crystal cell 130-1 and the second liquid crystal cell 130-2 are arranged in such a manner that the extension direction of the first electrode 136-1 of the first liquid crystal cell 130-1 is perpendicular to the extension direction of the first electrode 136-2 of the second liquid crystal cell 130-2 or intersects at an angle of 80° or more and 90° or less. In this structure, the extension direction of the second electrode 138-1 of the first liquid crystal cell 130-1 is also perpendicular to the extension direction of the second electrode 138-2 of the second liquid crystal cell 130-2 or intersects at an angle of 80° or more and 90° or less. In addition, the λ / 4 film 150 is arranged in the same manner as the optical element 120. Although not shown in the figure, the optical element 124 may also include an anti-reflection film 166 on the bottom surface side of the substrate 132 of the first liquid crystal cell 130-1.

[0115] like Fig.25As shown, in the optical element 124, when the first electrode 136 and the second electrode 138 of the first liquid crystal unit 130-1 and the second liquid crystal unit 130-2 are both driven, the polarization component x of the light incident from the light source 110 stays after passing through the liquid crystal layer 140-1 and the liquid crystal layer 140-2, respectively, and rotates by 90°. However, if the light passes through the λ / 4 film 150, it is reflected on the reflection plate 160 and then passes through the λ / 4 film 150 again, and then becomes the polarization component y. When the polarization component y passes through the liquid crystal layer 140-2 and the liquid crystal layer 140-1 again in sequence, it diffuses in the x direction and the y direction in each of the liquid crystal layer 140-2 and the liquid crystal layer 140-1, and provides the diffused polarization component x. Similarly, when the polarization component y of the light from the light source 110 is incident on the optical element 122, it is diffused in the y direction and the x direction by the liquid crystal layer 140-1 and the liquid crystal layer 140-2, respectively, and after being reflected by the reflector 160, it is optically rotated by 90° by the liquid crystal layer 140-1 and the liquid crystal layer 140-2 to provide the polarization component y. Thus, in the optical element 124, each polarization component is diffused by both the first liquid crystal unit 130-1 and the second liquid crystal unit 130-2. Therefore, as described above, the optical element 124 is configured in such a manner that the first electrode 136 does not completely overlap between the two liquid crystal units 130 and the second electrode 138 does not completely overlap in the z direction (see Fig.19B , Fig. 20B ) can provide a lighting device that effectively suppresses the occurrence of uneven illumination and uneven color.

[0116] Therefore, similar to the optical element 122, the light from the light source 110 can be diffused multiple times in the x-direction and the y-direction (for example, diffused three times or more), so that an irradiation area having a variety of shapes such as a circle, an ellipse, and a line can be obtained, and a larger irradiation area can be obtained. In addition, the coloring of light caused by insufficient diffusion can also be suppressed.

[0117] As described above, by using the optical elements 120, 122, and 124 according to the embodiments of the present invention, it is possible to process the light from the light source 110 into light that provides an arbitrary irradiation area using fewer liquid crystal cells than before. In addition, by using the optical elements 122 and 124, in particular, it is possible to diffuse the light multiple times using two liquid crystal cells 130, so that the coloring of the processed light can be suppressed. Therefore, the lighting device 100 including the optical elements 120, 122, or 124 according to the embodiments of the present invention can function as a lighting device that can provide various irradiation areas.

[0118] As embodiments of the present invention, the above-mentioned embodiments can be appropriately combined and implemented as long as they are not contradictory. In addition, based on the display device of each embodiment, the addition, deletion or design change of the constituent elements, or the addition, omission or condition change of the process appropriately performed by those skilled in the art are all included in the scope of the present invention as long as they have the gist of the present invention.

[0119] Any other effects different from the effects brought about by the above-described embodiments, which are clearly described in this specification or easily predicted by a person skilled in the art, are understood to be related to the present invention.

[0120] Description of Reference Numerals

[0121] 100: lighting device; 110: light source; 112: subject; 112a: recess; 114: light emitting element; 120: optical element; 122: optical element; 124: optical element; 130: liquid crystal unit; 130-1: first liquid crystal unit; 130-2: second liquid crystal unit; 132: substrate; 134: opposing substrate; 134-2: opposing substrate; 136: first electrode; 136-1: first electrode; 136-2: first electrode; 136a: bending point; 136b: straight line portion; 138: second electrode; 138-1: second electrode; 138-2: second electrode; 140: liquid crystal layer; 140-1: liquid crystal layer; 140-2: liquid crystal layer; 142: first orientation film; 144: second orientation film; 146: sealing member; 150: λ / 4 film; 152: bonding layer; 154-1: first wiring; 154-2: second wiring; 154-3: third wiring; 154-4: fourth wiring; 156: terminal; 160: reflection plate; 162: reflection film; 164: supporting substrate; 166: anti-reflection film; 168: insulating layer; 170: rotating mechanism; 172: virtual irradiation area; 174: irradiation area; 174-1: irradiation area; 174-2: irradiation area; 174-3: irradiation area; 174-4: irradiation area; 174-5: irradiation area; 174-6: irradiation area.

Claims

1. An optical element, comprising: Liquid crystal cell; λ / 4 film on the liquid crystal cell; as well as The reflector on the λ / 4 film, The liquid crystal unit comprises: A plurality of first electrodes extending in a first extension direction and arranged in a stripe shape; a first alignment film on the first electrode; a liquid crystal layer, located on the first alignment film, comprising liquid crystal molecules; A second alignment film on the liquid crystal layer; and A plurality of second electrodes are located on the second alignment film and arranged in a stripe shape, and the plurality of second electrodes extend in a second extension direction intersecting the first extension direction at an angle of not less than 80° and not more than 90°.

2. The optical element according to claim 1, wherein The first alignment film and the second alignment film are configured to respectively align the liquid crystal molecules in a first alignment direction and a second alignment direction intersecting with each other in the absence of an electric field. The first orientation direction intersects the first extension direction at an angle of not less than 80° and not more than 90°, The second alignment direction intersects the second stretching direction at an angle of not less than 80° and not more than 90°.

3. The optical element according to claim 1, wherein The plurality of first electrodes are configured to be applied with first alternating voltages having opposite phases between adjacent first electrodes. The plurality of second electrodes are configured such that a second AC voltage having opposite phases is applied between adjacent second electrodes.

4. A lighting device comprising: The optical element according to claim 1; and The light source is configured to irradiate light to the reflection plate via the liquid crystal unit.

5. An optical element comprising: a first liquid crystal unit; a second liquid crystal cell on the first liquid crystal cell; and The reflective plate on the second liquid crystal unit, The first liquid crystal unit and the second liquid crystal unit respectively include: A plurality of first electrodes arranged in a stripe shape; a first alignment film on the plurality of first electrodes; a liquid crystal layer, located on the first alignment film, comprising liquid crystal molecules; A second alignment film on the liquid crystal layer; and A plurality of second electrodes are located on the second alignment film and arranged in a stripe shape, and the plurality of second electrodes intersect the plurality of first electrodes at an angle of not less than 80° and not more than 90°.

6. The optical element according to claim 5, wherein: In each of the first liquid crystal cell and the second liquid crystal cell, The first alignment film and the second alignment film are configured to align the liquid crystal molecules in directions intersecting each other at an angle of 80° or more and 90° or less in the absence of an electric field. In the absence of an electric field, the direction in which the first alignment film aligns the liquid crystal molecules intersects the direction in which the plurality of first electrodes extend at an angle of not less than 80° and not more than 90°. The direction in which the second alignment film aligns the liquid crystal molecules in the absence of an electric field intersects the direction in which the plurality of second electrodes extend at an angle of not less than 80° and not more than 90°.

7. The optical element according to claim 5, wherein: An angle formed by a direction in which the plurality of first electrodes of the first liquid crystal cell extend and a direction in which the plurality of first electrodes of the second liquid crystal cell extend is greater than or equal to 0° and less than or equal to 10°.

8. The optical element according to claim 5, wherein: A λ / 4 film is further provided between the second liquid crystal unit and the reflector. An angle formed by a direction in which the plurality of first electrodes of the first liquid crystal cell extend and a direction in which the plurality of first electrodes of the second liquid crystal cell extend is greater than or equal to 80° and less than or equal to 90°.

9. The optical element according to claim 5, wherein: In each of the first liquid crystal cell and the second liquid crystal cell, The plurality of first electrodes are configured to be applied with first alternating voltages having opposite phases between adjacent first electrodes. The plurality of second electrodes are configured such that a second AC voltage having opposite phases is applied between adjacent second electrodes.

10. A lighting device comprising: The optical element according to claim 5; and The light source is configured to irradiate light toward the reflection plate via the first liquid crystal cell and the second liquid crystal cell.

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